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  • 301.
    Carralero, D.
    et al.
    Max Planck Inst Plasma Phys, Boltzmannstr 2, D-85748 Garching, Germany.;Max Planck Inst Plasma Phys, D-85748 Garching, Germany..
    Bergsåker, Henric
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Bykov, Igor
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Elevant, Thomas
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Frassinetti, Lorenzo
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Garcia-Carrasco, Alvaro
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Hellsten, Torbjörn
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Ivanova, Darya
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Johnson, Thomas
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Menmuir, Sheena
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Petersson, Per
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Rachlew, Elisabeth
    KTH, School of Engineering Sciences (SCI), Physics.
    Rubel, Marek
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Ström, Petter
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Tholerus, Emmi
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Weckmann, Armin
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Zychor, I.
    Inst Plasma Phys & Laser Microfus, PL-01497 Warsaw, Poland..
    et al.,
    Experimental Validation of a Filament Transport Model in Turbulent Magnetized Plasmas2015In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 115, no 21, article id 215002Article in journal (Refereed)
    Abstract [en]

    In a wide variety of natural and laboratory magnetized plasmas, filaments appear as a result of interchange instability. These convective structures substantially enhance transport in the direction perpendicular to the magnetic field. According to filament models, their propagation may follow different regimes depending on the parallel closure of charge conservation. This is of paramount importance in magnetic fusion plasmas, as high collisionality in the scrape-off layer may trigger a regime transition leading to strongly enhanced perpendicular particle fluxes. This work reports for the first time on an experimental verification of this process, linking enhanced transport with a regime transition as predicted by models. Based on these results, a novel scaling for global perpendicular particle transport in reactor relevant tokamaks such as ASDEX-Upgrade and JET is found, leading to important implications for next generation fusion devices.

  • 302. Carroll, R. J.
    et al.
    Page, R. D.
    Joss, D. T.
    Uusitalo, J.
    Darby, I. G.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Eeckhaudt, S.
    Grahn, T.
    Gray-Jones, C.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppänen, A. -P
    Nyman, M.
    O'Donnell, D.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Blurring the Boundaries: Decays of Multiparticle Isomers at the Proton Drip Line2014In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 112, no 9, p. 092501-Article in journal (Refereed)
    Abstract [en]

    A multiparticle spin-trap isomer has been discovered in the proton-unbound nucleus 158 73 Ta 85. The isomer mainly decays by (h) over bar -ray emission with a half-life of 6.1d(1) mu s. Analysis of the gamma-ray data shows that the isomer lies 2668 keV above the known 9(+) state and has a spin 10h higher and negative parity. This 19(-) isomer also has an 8644(11) keV, 1.4(2)% alpha-decay branch that populates the 9(+) state in Lu-154. No proton-decay branch from the isomer was identified, despite the isomer being unbound to proton emission by 3261(14) keV. This remarkable stability against proton emission is compared with theoretical predictions, and the implications for the extent of observable nuclides are considered.

  • 303.
    Castro-Alvaredo, Olalla A.
    et al.
    City Univ London, Dept Math, 10 Northampton Sq, London EC1V 0HB, England..
    Lencses, Mate
    BME Dept Theoret Phys, Budafoki Ut 8, H-1111 Budapest, Hungary.;BME Momentum Stat Field Theory Res Grp, Budafoki Ut 8, H-1111 Budapest, Hungary..
    Szecsenyi, Istvan
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Viti, Jacopo
    Univ Fed Rio Grande do Norte, Int Inst Phys, BR-59078970 Natal, RN, Brazil.;Univ Fed Rio Grande do Norte, ECT, BR-59078970 Natal, RN, Brazil.;INFN, Sez Firenze, Via G Sansone 1, I-50019 Florence, Italy..
    Entanglement Oscillations near a Quantum Critical Point2020In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 124, no 23, article id 230601Article in journal (Refereed)
    Abstract [en]

    We study the dynamics of entanglement in the scaling limit of the Ising spin chain in the presence of both a longitudinal and a transverse field. We present analytical results for the quench of the longitudinal field in the critical transverse field which go beyond current lattice integrability techniques. We test these results against a numerical simulation on the corresponding lattice model finding extremely good agreement. We show that the presence of bound states in the spectrum of the field theory leads to oscillations in the entanglement entropy and suppresses its linear growth on the time scales accessible to numerical simulations. For small quenches, we exactly determine these oscillatory contributions and demonstrate that their presence follows from symmetry arguments. For the quench of the transverse field at zero longitudinal field, we prove that the Renyi entropies are exactly proportional to the logarithm of the exponential of a time-dependent function, whose leading large-time behavior is linear, hence, entanglement grows linearly. We conclude that, in the scaling limit, linear growth and oscillations in the entanglement entropies can not be simply seen as consequences of integrability and its breaking, respectively.

  • 304.
    Cederwall, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, M.
    Univ Liverpool, Oliver Lodge Lab, Dept Phys, Liverpool L69 7ZE, Merseyside, England..
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ertoprak, Aysegul
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Grahn, T.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Cullen, D. M.
    Univ Manchester, Sch Phys & Astron, Schuster Bldg, Manchester M13 9PL, Lancs, England..
    Hodge, D.
    Univ Manchester, Sch Phys & Astron, Schuster Bldg, Manchester M13 9PL, Lancs, England..
    Giles, M.
    Univ Manchester, Sch Phys & Astron, Schuster Bldg, Manchester M13 9PL, Lancs, England..
    Stolze, S.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Badran, H.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Braunroth, T.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Calverley, T.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Cox, D. M.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland.;Lund Univ, Dept Phys, S-22100 Lund, Sweden..
    Fang, Y. D.
    Osaka Univ, Res Ctr Nucl Phys, JP-5670047 Osaka, Japan..
    Greenlees, P. T.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Hilton, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Ideguchi, E.
    Osaka Univ, Res Ctr Nucl Phys, JP-5670047 Osaka, Japan..
    Julin, R.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Juutinen, S.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Raju, M. Kumar
    Osaka Univ, Res Ctr Nucl Phys, JP-5670047 Osaka, Japan..
    Li, H.
    CEA, GANIL, DSMa, CNRS,IN2P3, F-14076 Caen 5, France..
    Liu, H.
    KTH.
    Matta, Sanya
    KTH, School of Engineering Sciences (SCI), Physics.
    Modamio, V.
    Univ Oslo, Dept Phys, NO-0316 Oslo, Norway..
    Pakarinen, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Papadakis, P.
    Univ Liverpool, Oliver Lodge Lab, Dept Phys, Liverpool L69 7ZE, Merseyside, England.;Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Partanen, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Petrache, C. M.
    Univ Paris Saclay, Ctr Sci Nucl & Sci Mat, CNRS, IN2P3, F-91405 Orsay, France..
    Rahkila, P.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Ruotsalainen, P.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Sandzelius, M.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Saren, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Scholey, C.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Sorri, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland.;Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy.;Sodankyla Geophys Observ, FI-99600 Sodankyla, Finland..
    Subramaniam, Pranav
    KTH.
    Taylor, M. J.
    Univ Manchester, Sch Med Sci, Div Canc Sci, Manchester M13 9PL, Lancs, England..
    Uusitalo, J.
    Univ Jyvaskyla, Epartment Phys, POB 35, FI-40014 Jyvaskyla, Finland..
    Valiente-Dobon, J. J.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Lifetime Measurements of Excited States in Pt-172 and the Variation of Quadrupole Transition Strength with Angular Momentum2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 121, no 2, article id 022502Article in journal (Refereed)
    Abstract [en]

    Lifetimes of the first excited 2(+) and 4(+) states in the extremely neutron -deficient nuclide Pt-172 have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) = 0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segre chart. The observation adds to a cluster of a few extremely neutron -deficient nuclides of the heavy transition metals with neutron numbers N approximate to 90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N approximate to 90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

  • 305. Cederwall, Bo
    et al.
    JANSSENS, RVF
    BRINKMAN, MJ
    LEE, IY
    AHMAD, I
    BECKER, JA
    CARPENTER, MP
    CROWELL, B
    DELEPLANQUE, MA
    DIAMOND, RM
    DRAPER, JE
    DUYAR, C
    FALLON, P
    FARRIS, LP
    HENRY, EA
    HENRY, RG
    HUGHES, JR
    KHOO, TL
    LAURITSEN, T
    MACCHIAVELLI, AO
    RUBEL, E
    STEPHENS, FS
    STOYER, MA
    SATULA, W
    WIEDENHOEVER, I
    WYSS, R
    NEW FEATURES OF SUPERDEFORMED BANDS IN HG-1941994In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 72, no 20, p. 3150-3153Article in journal (Refereed)
    Abstract [en]

    Two new features of superdeformed (SD) bands in the A almost-equal-to 190 region emerge from a study of Hg-194 with the Gammasphere detector array. A decrease of the dynamic moment of inertia is observed for rotational frequencies HBARomega greater-than-or-equal-to 0.4 MeV, confirming long standing expectations based on mean field calculations with pairing. Evidence for a small staggering in the SD transition energies is also observed, suggesting the presence of terms with fourfold symmetry in the SD Hamiltonian.

  • 306.
    Cederwall, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liu, Xiaoyu
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ertoprak, Aysegul
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhang, Wei
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Clement, E.
    de France, G.
    Ralet, D.
    Gadea, A.
    Goasduff, A.
    Jaworski, G.
    Kuti, I.
    Nyako, B. M.
    Nyberg, J.
    Palacz, M.
    Wadsworth, R.
    Valiente-Dobon, J. J.
    Al-Azri, H.
    Nyberg, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    de Angelis, G.
    Doncel, M.
    Dudouet, J.
    Gottardo, A.
    Jurado, M.
    Ljungvall, J.
    Mengoni, D.
    Napoli, D. R.
    Petrache, C. M.
    Sohler, D.
    Timar, J.
    Barrientos, D.
    Bednarczyk, P.
    Benzoni, G.
    Birkenbach, B.
    Boston, A. J.
    Boston, H. C.
    Burrows, I.
    Charles, L.
    Ciemala, M.
    Crespi, F. C. L.
    Cullen, D. M.
    Desesquelles, P.
    Domingo-Pardo, D.
    Eberth, J.
    Erduran, N.
    Erturk, S.
    Gonzalez, V.
    Goupil, J.
    Hess, H.
    Huyuk, T.
    Jungclaus, A.
    Korten, W.
    Lemasson, A.
    Leoni, S.
    Maj, A.
    Menegazzo, R.
    Million, B.
    Perez-Vidal, R. M.
    Podolyak, Zs.
    Pullia, A.
    Recchia, F.
    Reiter, P.
    Saillant, F.
    Salsac, M. D.
    Sanchis, E.
    Simpson, J.
    Stezowski, O.
    Theisen, C.
    Zielinska, M.
    Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus Ru 882020In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 124, no 6Article in journal (Refereed)
    Abstract [en]

    The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide 88Ru has been measured using the combination of the Advanced Gamma Tracking Array (AGATA)spectrometer, the NEDA, and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in 88 Ru were populated via the 54 Feð 36 Ar; 2nγÞ 88 Ru fusion-evaporationreaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex. The observed γ-ray cascade is assigned to 88 Ru using clean prompt γ-γ-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N > Z nuclides. The direct observation of such a “delayed” rotational alignment in a deformed N 1⁄4 Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.

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  • 307. Celani, A.
    et al.
    Bo, Stefano
    KTH, School of Computer Science and Communication (CSC), Computational Biology, CB. KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Eichhorn, Ralf
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Aurell, Erik
    KTH, School of Computer Science and Communication (CSC), Computational Biology, CB. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Anomalous thermodynamics at the microscale2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 26, p. 260603-Article in journal (Refereed)
    Abstract [en]

    Particle motion at the microscale is an incessant tug-of-war between thermal fluctuations and applied forces on one side and the strong resistance exerted by fluid viscosity on the other. Friction is so strong that completely neglecting inertia - the overdamped approximation - gives an excellent effective description of the actual particle mechanics. In sharp contrast to this result, here we show that the overdamped approximation dramatically fails when thermodynamic quantities such as the entropy production in the environment are considered, in the presence of temperature gradients. In the limit of vanishingly small, yet finite, inertia, we find that the entropy production is dominated by a contribution that is anomalous, i.e., has no counterpart in the overdamped approximation. This phenomenon, which we call an entropic anomaly, is due to a symmetry breaking that occurs when moving to the small, finite inertia limit. Anomalous entropy production is traced back to futile phase-space cyclic trajectories displaying a fast downgradient sweep followed by a slow upgradient return to the original position.

  • 308. Cerf, N. J.
    et al.
    Bourennane, M.
    Karlsson, Anders
    KTH, Superseded Departments (pre-2005), Microelectronics and Information Technology, IMIT.
    Gisin, N.
    Security of quantum key distribution using d-level systems2002In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 88, no 12Article in journal (Refereed)
    Abstract [en]

    We consider two quantum cryptographic schemes relying on encoding the key into qudits, i.e., quantum states in a d-dimensional Hilbert space. The first cryptosystem uses two mutually unbiased bases (thereby extending the BB84 scheme), while the second exploits all d + 1 available such bases (extending the six-state protocol for qubits). We derive the information gained by a potential eavesdropper applying a cloning-based individual attack, along with an upper bound on the error rate that ensures unconditional security against coherent attacks.

  • 309.
    Champenois, Elio G.
    et al.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    H. List, Nanna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Ware, Matthew
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Britton, Mathew
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Bucksbaum, Philip H.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Cheng, Xinxin
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Centurion, Martin
    Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA.
    Cryan, James P.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Forbes, Ruaridh
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Gabalski, Ian
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
    Hegazy, Kareem
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Physics, Stanford University, Stanford, California 94305, USA.
    Hoffmann, Matthias C.
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Howard, Andrew J.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
    Ji, Fuhao
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Lin, Ming Fu
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Nunes, J. Pedro F.
    Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA.
    Shen, Xiaozhe
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Yang, Jie
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Chemistry, Tsinghua University, Beijing 100084, China.
    Wang, Xijie
    SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Martinez, Todd J.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Department of Chemistry, Stanford University, Stanford, California 94305, USA.
    Wolf, Thomas J.A.
    Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
    Femtosecond Electronic and Hydrogen Structural Dynamics in Ammonia Imaged with Ultrafast Electron Diffraction2023In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 131, no 14, article id 143001Article in journal (Refereed)
    Abstract [en]

    Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction. Both assignments are confirmed by ab initio simulations of the photochemical dynamics and the resulting diffraction observable. While the temporal resolution of the experiment is insufficient to resolve the dissociation in time, our results represent an important step towards the observation of proton dynamics in real space and time.

  • 310. Chang, Guoqing
    et al.
    Xu, Su-Yang
    Wieder, Benjamin J.
    Nordita SU.
    Sanchez, Daniel S.
    Huang, Shin-Ming
    Belopolski, Ilya
    Chang, Tay-Rong
    Zhang, Songtian
    Bansil, Arun
    Lin, Hsin
    Hasan, M. Zahid
    Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi2017In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 119, no 20, article id 206401Article in journal (Refereed)
    Abstract [en]

    The theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. In particular, the Fermi surfaces of chiral semimetals carry quantized Chern numbers, making them an attractive platform for the observation of exotic transport and optical phenomena. While the simplest example of a chiral fermion in condensed matter is a conventional vertical bar C vertical bar = 1 Weyl fermion, recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. In this Letter, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a filling-enforced semimetal that features near its Fermi surface a chiral double sixfold-degenerate spin-1 Weyl node at R and a previously uncharacterized fourfold-degenerate chiral fermion at Gamma. Each unconventional fermion displays Chern number +/- 4 at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.

  • 311. Chen, L. -J
    et al.
    Wang, S.
    Wilson, L. B. , I I I
    Schwartz, S.
    Bessho, N.
    Moore, T.
    Gershman, D.
    Giles, B.
    Malaspina, D.
    Wilder, F. D.
    Ergun, R. E.
    Hesse, M.
    Lai, H.
    Russell, C.
    Strangeway, R.
    Torbert, R. B.
    Vinas, F. -A
    Burch, J.
    Lee, S.
    Pollock, C.
    Dorelli, J.
    Paterson, W.
    Ahmadi, N.
    Goodrich, K.
    Lavraud, B.
    Le Contel, O.
    Khotyaintsev, Yu.V.
    Lindqvist, Per-Arne
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Space and Plasma Physics.
    Boardsen, S.
    Wei, H.
    Le, A.
    Avanov, L.
    Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 22, article id 225101Article in journal (Refereed)
    Abstract [en]

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating. 

  • 312. Chen, Lan
    et al.
    Hu, Zhenpeng
    Zhao, Aidi
    Wang, Bing
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Yang, Jinlong
    Hou, J. G.
    Mechanism for negative differential resistance in molecular electronic devices: Local orbital symmetry matching2007In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, no 14Article in journal (Refereed)
    Abstract [en]

    A new mechanism for negative differential resistance (NDR) originating from local orbital symmetry matching between an electrode and a molecule in a single molecular electronic device is proposed and demonstrated by a joint experimental and theoretical scanning tunneling microscope study of a cobalt phthalocyanines (CoPc) molecule on a gold substrate. For two different metal tips used, Ni and W, NDR occurs only with Ni tips and shows no dependence on the geometrical shape of the tip. Calculations reveal that such a behavior is a result of local orbital symmetry matching between the Ni tip and Co atom.

  • 313.
    Chen, L-J
    et al.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Wang, S.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Le Contel, O.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, CNRS,Ecole Polytech, F-91128 Paris, France..
    Rager, A.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Hesse, M.
    Univ Bergen, N-5020 Bergen, Norway..
    Drake, J.
    Univ Maryland, College Pk, MD 20747 USA..
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Ng, J.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Bessho, N.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Graham, D.
    Swedish Inst Space Phys, SE-75121 Uppsala, Sweden..
    Wilson, Lynn B., III
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Moore, T.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Giles, B.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Lavraud, B.
    Univ Toulouse UPS, CNRS, CNES, Inst Rech Astrophys & Planetol, F-31027 Toulouse 4, France..
    Genestreti, K.
    Univ New Hampshire, Durham, NH 03824 USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Khotyaintsev, Yu, V
    Swedish Inst Space Phys, SE-75121 Uppsala, Sweden..
    Ergun, R. E.
    Univ Colorado, Boulder, CO 80305 USA..
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA..
    Burch, J.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Pollock, C.
    Denali Sci, Healy, AK 99743 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Lindqvist, Per-Arne
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Space and Plasma Physics.
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Lower-Hybrid Drift Waves Driving Electron Nongyrotropic Heating and Vortical Flows in a Magnetic Reconnection Layer2020In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 125, no 2, article id 025103Article in journal (Refereed)
    Abstract [en]

    We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer.

  • 314. Chen, Long
    et al.
    He, Sailing
    KTH, Superseded Departments (pre-2005), Electromagnetic Theory.
    Shen, Linfang
    Finite-size effects of a left-handed material slab on the image quality2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 10Article in journal (Refereed)
    Abstract [en]

    The characteristics of an imaging system formed by a left-handed material (LHM) slab of finite length are studied, and the influence of the finite length of the slab on the image quality is analyzed. Unusual phenomena such as surface bright spots and negative energy stream at the image side are observed and explained as the cavity effects of surface plasmons excited by the evanescent components of the incident field. For a thin LHM slab, the cavity effects are found rather sensitive to the length of the slab; the bright spots on the bottom surface of the slab may stretch to the image plane and degrade the image quality.

  • 315. Chen, P.
    et al.
    Ong, Yen Chin
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Page, D. N.
    Sasaki, M.
    Yeom, D. -H
    Naked Black Hole Firewalls2016In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 116, no 16, article id 161304Article in journal (Refereed)
    Abstract [en]

    In the firewall proposal, it is assumed that the firewall lies near the event horizon and should not be observable except by infalling observers, who are presumably terminated at the firewall. However, if the firewall is located near where the horizon would have been, based on the spacetime evolution up to that time, later quantum fluctuations of the Hawking emission rate can cause the "teleological" event horizon to have migrated to the inside of the firewall location, rendering the firewall naked. In principle, the firewall can be arbitrarily far outside the horizon. This casts doubt about the notion that firewalls are the "most conservative" solution to the information loss paradox.

  • 316.
    Chen, S.
    et al.
    Univ Hong Kong, Dept Phys, Pokfulam, Hong Kong 999077, Peoples R China.;RIKEN Nishina Ctr, Wako, Saitama 3510198, Japan.;Peking Univ, Sch Phys, Beijing 100871, Peoples R China.;Peking Univ, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China..
    Liu, H. N.
    KTH, School of Engineering Sciences (SCI), Physics. Univ Paris Saclay, CEA, IRFU, F-91191 Gif Sur Yvette, France.;Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zanetti, L.
    RIKEN Nishina Ctr, Wako, Saitama 3510198, Japan.;Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Quasifree Neutron Knockout from Ca-54 Corroborates Arising N=34 Neutron Magic Number2019In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 14, article id 142501Article in journal (Refereed)
    Abstract [en]

    Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a Ca-54 beam striking on a liquid hydrogen target at similar to 200 MeV/u. A significantly larger cross section to the p(3/2), state compared to the f(5/2) state observed in the excitation of Ca-53 provides direct evidence for the nature of the N = 34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

  • 317. Cherepov, S. S.
    et al.
    Koop, B. C.
    Galkin, A. Yu.
    Khymyn, R. S.
    Ivanov, B. A.
    Worledge, D. C.
    Korenivski, Vladislav
    Core-Core Dynamics in Spin Vortex Pairs (Vol 109, 097204, 2012)2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 13, article id 139902Article in journal (Refereed)
  • 318.
    Cherepov, Sergiy
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Dzhezherya, Yu. I.
    Worledge, D. C.
    Korenivski, Vladislav
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Resonant Activation of a Synthetic Antiferromagnet2011In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 107, no 7, p. 077202-Article in journal (Refereed)
    Abstract [en]

    The magnetic decay time of a synthetic antiferromagnet comprised of two closely spaced magnetic dipoles is measured in the presence of microwave excitation. The system is known to be highly stable with respect to switching between its two antiparallel ground states under quasistatic magnetic fields. We show that an order of magnitude lower field can switch the pair, provided the field is applied in resonance with the optical eigenmode of the collective spin dynamics in the system. We furthermore show that thermal agitation can play an essential role in spin-flop switching for resonant excitations of near-or subcritical amplitude.

  • 319.
    Cherepov, Sergiy
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Koop, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Galkin, A. Yu.
    Khymyn, R.S.
    Institute of Magnetism, Ukrainian Academy of Science.
    Ivanov, B. A.
    Institute of Magnetism, Ukrainian Academy of Science.
    Worledge, D. C.
    IBM T.J. Watson Researh Center.
    Korenivski, Vladislav
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Core-Core Dynamics in Spin Vortex Pairs2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 9, p. 097204-Article in journal (Refereed)
    Abstract [en]

    We investigate nanopillars in which two thin ferromagnetic particles are separated by a nanometer thin nonmagnetic spacer and can be set into stable spin vortex-pair configurations. We find that the previously unexplored limit of strong vortex core-core coupling can dominate the spin dynamics in the system. We observe experimentally and explain analytically and numerically how the 0.2 GHz gyrational resonance modes of the individual vortices are transformed into a 2 GHz collective rotational resonance mode in the configurations where the two cores form a bound pair.

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  • 320. Chia, Han-Jong
    et al.
    Guo, Feng
    Belova, Liubov M.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    McMichael, R. D.
    Nanoscale Spin Wave Localization Using Ferromagnetic Resonance Force Microscopy2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 108, no 8, p. 087206-Article in journal (Refereed)
    Abstract [en]

    We use the dipolar fields from a magnetic cantilever tip to generate localized spin wave precession modes in an in-plane magnetized, thin ferromagnetic film. Multiple resonances from a series of localized modes are detected by ferromagnetic resonance force microscopy and reproduced by micromagnetic models that also reveal highly anisotropic mode profiles. Modeled scans of line defects using the lowest-frequency mode provide resolution predictions of (94.5 +/- 1.5) nm in the field direction, and (390 +/- 2) nm perpendicular to the field.

  • 321. Chimata, Raghuveer
    et al.
    Bergman, Anders
    Bergqvist, Lars
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Sanyal, Biplab
    Eriksson, Olle
    Microscopic Model for Ultrafast Remagnetization Dynamics2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 15, p. 157201-Article in journal (Refereed)
    Abstract [en]

    In this Letter, we provide a microscopic model for the ultrafast remagnetization of atomic moments already quenched above the Stoner-Curie temperature by a strong laser fluence. Combining first-principles density functional theory, atomistic spin dynamics utilizing the Landau-Lifshitz-Gilbert equation, and a three-temperature model, we analyze the temporal evolution of atomic moments as well as the macroscopic magnetization of bcc Fe and hcp Co covering a broad time scale, ranging from femtoseconds to picoseconds. Our simulations show a variety of complex temporal behavior of the magnetic properties resulting from an interplay between electron, spin, and lattice subsystems, which causes an intricate time evolution of the atomic moment, where longitudinal and transversal fluctuations result in a macrospin moment that evolves highly nonmonotonically.

  • 322. Chiodaroli, M.
    et al.
    Guenaydin, M.
    Johansson, Henrik
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA. Department of Physics and Astronomy, Uppsala University, 75108 Uppsala, Sweden.
    Roiban, R.
    Complete Construction of Magical, Symmetric, and Homogeneous N=2 Supergravities as Double Copies of Gauge Theories2016In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 117, no 1, article id 011603Article in journal (Refereed)
    Abstract [en]

    We show that scattering amplitudes in magical, symmetric or homogeneous N = 2 Maxwell-Einstein supergravities can be obtained as double copies of two gauge theories, using the framework of color-kinematics duality. The left-hand copy is N = 2 super-Yang-Mills theory coupled to a hypermultiplet, whereas the right-hand copy is a nonsupersymmetric theory that can be identified as the dimensional reduction of a D-dimensional Yang-Mills theory coupled to P fermions. For generic D and P, the double copy gives homogeneous supergravities. For P = 1 and D = 7, 8, 10, 14, it gives the magical supergravities. We compute explicit amplitudes, discuss their soft limits, and study the UV behavior at one loop.

  • 323.
    Chiodaroli, M.
    et al.
    Uppsala Univ, Dept Phys & Astron, S-75108 Uppsala, Sweden.;Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA..
    Gunaydin, M.
    Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA.;Penn State Univ, Inst Gravitat & Cosmos, University Pk, PA 16802 USA..
    Johansson, Henrik
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA. Uppsala Univ, Dept Phys & Astron, S-75108 Uppsala, Sweden.;Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA..
    Roiban, R.
    Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA.;Penn State Univ, Inst Gravitat & Cosmos, University Pk, PA 16802 USA..
    Gauged Supergravities and Spontaneous Supersymmetry Breaking from the Double Copy Construction2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 17, article id 171601Article in journal (Refereed)
    Abstract [en]

    Supergravities with gauged R symmetry and Minkowski vacua allow for spontaneous supersymmetry breaking and, as such, provide a framework for building supergravity models of phenomenological relevance. In this Letter, we initiate the study of double copy constructions for these supergravities. We argue that, on general grounds, we expect their scattering amplitudes to be described by a double copy of the type (spontaneously broken gauge theory)circle times (gauge theory with broken supersymmetry). We present a simple realization in which the resulting supergravity has U(1)(R) gauge symmetry, spontaneously broken N = 2 supersymmetry, and massive gravitini. This is the first instance of a double copy construction of a gauged supergravity and of a theory with spontaneously broken supersymmetry. The construction extends in a straightforward manner to a large family of gauged Yang-Mills-Einstein supergravity theories with or without spontaneous gauge-symmetry breaking.

  • 324. Chung, J. -H
    et al.
    Chung, S. J.
    Lee, S.
    Kirby, B. J.
    Borchers, J. A.
    Cho, Y. J.
    Liu, X.
    Furdyna, J. K.
    Carrier-mediated antiferromagnetic interlayer exchange coupling in diluted magnetic semiconductor multilayers Ga1-xMnxAs/GaAs:Be2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 23Article in journal (Refereed)
    Abstract [en]

    We report the antiferromagnetic (AFM) interlayer exchange coupling between Ga0.97Mn0.03As ferromagnetic semiconductor layers separated by Be-doped GaAs spacers. Polarized neutron reflectivity reveals a characteristic splitting at the wave vector corresponding to twice the multilayer period, indicating that the coupling between the ferromagnetic layers is AFM. When the applied field is increased to above the saturation field, this AFM coupling is suppressed. This behavior is not observed when the spacers are undoped, suggesting that the observed AFM coupling is mediated by doped charge carriers. © 2008 The American Physical Society.

  • 325.
    Chung, Sunjae
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Uppsala Univ, Dept Phys & Astron, S-75120 Uppsala, Sweden..
    Le, Quang Tuan
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Ahlberg, Martina
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;NanOsc AB, S-16440 Kista, Sweden..
    Awad, Ahmad A.
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;NanOsc AB, S-16440 Kista, Sweden..
    Weigand, Markus
    Max Planck Inst Intelligent Syst, D-70569 Stuttgart, Germany..
    Bykova, Iuliia
    Max Planck Inst Intelligent Syst, D-70569 Stuttgart, Germany..
    Khymyn, Roman
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Dvornik, Mykola
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Mazraati, Hamid
    KTH, School of Engineering Sciences (SCI), Applied Physics. NanOsc AB, S-16440 Kista, Sweden..
    Houshang, Afshin
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;NanOsc AB, S-16440 Kista, Sweden..
    Jiang, Sheng
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Anh Nguyen, T. N.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.; Vietnam Acad Sci & Technol, Inst Mat Sci, Lab Magnetism & Superconduct, 18 Hoang Quoc Viet, Hanoi 122300, Vietnam..
    Goering, Eberhard
    Max Planck Inst Intelligent Syst, D-70569 Stuttgart, Germany..
    Schuetz, Gisela
    Max Planck Inst Intelligent Syst, D-70569 Stuttgart, Germany..
    Graefe, Joachim
    Max Planck Inst Intelligent Syst, D-70569 Stuttgart, Germany..
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;NanOsc AB, S-16440 Kista, Sweden..
    Direct Observation of Zhang-Li Torque Expansion of Magnetic Droplet Solitons2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 21, article id 217204Article in journal (Refereed)
    Abstract [en]

    Magnetic droplets are nontopological dynamical soli tons that can be nucleated in nanocontact based spin torque nano-oscillators (STNOs) with perpendicular magnetic anisotropy free layers. While theory predicts that the droplet should be of the same size as the nanocontact, its inherent drift instability has thwarted attempts at observing it directly using microscopy techniques. Here, we demonstrate highly stable magnetic droplets in all-perpendicular STNOs and present the first detailed droplet images using scanning transmission X-ray microscopy. In contrast to theoretical predictions, we find that the droplet diameter is about twice as large as the nanocontact. By extending the original droplet theory to properly account for the lateral current spread underneath the nanocontact, we show that the large discrepancy primarily arises from current-in-plane Zhang-Li torque adding an outward pressure on the droplet perimeter. Electrical measurements on droplets nucleated using a reversed current in the antiparallel state corroborate this picture.

  • 326. Citrin, J.
    et al.
    Jenko, F.
    Mantica, P.
    Told, D.
    Bourdelle, C.
    Garcia, J.
    Haverkort, J. W.
    Hogeweij, G. M. D.
    Johnson, Thomas
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Pueschel, M. J.
    Nonlinear stabilization of tokamak microturbulence by fast ions2013In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 111, no 15, p. 155001-Article in journal (Refereed)
    Abstract [en]

    Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting significantly the thermal pressure electromagnetic stabilization. Based on nonlinear gyrokinetic simulations investigating a set of ion heat transport experiments on the JET tokamak, described by Mantica et al., this result explains the experimentally observed ion heat flux and stiffness reduction. These findings are expected to improve the extrapolation of advanced tokamak scenarios to reactor relevant regimes.

  • 327.
    Claesson, Thomas
    et al.
    KTH, Superseded Departments (pre-2005), Microelectronics and Information Technology, IMIT.
    Månsson, Martin
    KTH, Superseded Departments (pre-2005), Microelectronics and Information Technology, IMIT.
    Dallera, Claudia
    INFM-Dipartimento di Fisica, Politecnico di Milano, Italy.
    Venturini, Federica
    Europ. Synchrt. Radiation Facility, Grenoble, France.
    De Nadaï, Celine
    Europ. Synchrt. Radiation Facility, Grenoble, France.
    Brookes, Nicholas B.
    Europ. Synchrt. Radiation Facility, Grenoble, France.
    Tjernberg, Oscar
    KTH, Superseded Departments (pre-2005), Microelectronics and Information Technology, IMIT.
    Angle Resolved Photoemission from Nd(1.85)Ce(0.15)CuO(4) using High Energy Photons: A Fermi Surface Investigation2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 13, p. 136402-1-136402-4Article in journal (Refereed)
    Abstract [en]

    We have performed an angle resolved photoemission study on a single crystal of the optimally electron doped (n-type) cuprate superconductor Nd2-xCexCuO4 (x=0.15) at a photon energy of 400 eV. The Fermi surface is mapped out and is, in agreement with earlier measurements, of hole-type with the expected Luttinger volume. However, comparing with previous low energy measurements, we observe a different Fermi surface shape and a different distribution of spectral intensity around the Fermi surface contour. The observed Fermi surface shape indicates a stronger electron correlation in the bulk as compared to the surface.

  • 328. Clark, R M
    et al.
    Lee, I Y
    Fallon, P
    Joss, D T
    Asztalos, S J
    Becker, J A
    Bernstein, L
    Cederwall, Bo
    Deleplanque, M A
    Diamond, R M
    Farris, L P
    Hauschild, K
    Kelly, W H
    Macchiavelli, A O
    Nolan, P J
    OBrien, N
    Semple, A T
    Stephens, F S
    Wadsworth, R
    Relative deformations of superdeformed bands in Ce-131,Ce-1321996In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 76, no 19, p. 3510-3513Article in journal (Refereed)
    Abstract [en]

    The quadrupole moments Q(0) of five superdeformed bands in Ce-131,Ce-132 have been established using the Doppler-shift attenuation method; for the first time, we can compare relative deformations of yrast and excited bands in different nuclei to an accuracy of similar or equal to(5-7)%. Four of the five bands have very similar deformations, while the excited band in Ce-131 has a somewhat larger quadrupole moment. Important new information is presented on the shape-driving force of the vi(13/2) orbital, the stability of the second minimum with respect to particle excitations, the relative deformations of identical bands, the nature of the sidefeeding, and the time scale of the decay process.

  • 329. Cocolios, T. E.
    et al.
    Dexters, W.
    Seliverstov, M. D.
    Andreyev, A. N.
    Antalic, S.
    Barzakh, A. E.
    Bastin, B.
    Buescher, J.
    Darby, I. G.
    Fedorov, D. V.
    Fedosseyev, V. N.
    Flanagan, K. T.
    Franchoo, S.
    Fritzsche, S.
    Huber, G.
    Huyse, M.
    Keupers, M.
    Koester, U.
    Kudryavtsev, Yu.
    Mane, E.
    Marsh, B. A.
    Molkanov, P. L.
    Page, R. D.
    Sjödin, Anna Marica
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Stefan, I.
    Van de Walle, J.
    Van Duppen, P.
    Venhart, M.
    Zemlyanoy, S. G.
    Bender, M.
    Heenen, P. -H
    Early Onset of Ground State Deformation in Neutron Deficient Polonium Isotopes2011In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, no 5, p. 052503-Article in journal (Refereed)
    Abstract [en]

    In-source resonant ionization laser spectroscopy of the even-A polonium isotopes Po-192-210,Po-216,Po-218 has been performed using the 6p(3)7s S-5(2) to (6)p(3)7p P-5(2) (lambda = 843.38 nm) transition in the polonium atom (Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope shifts in Po200-210 with a previous data set allows us to test for the first time recent large-scale atomic calculations that are essential to extract the changes in the mean-square charge radius of the atomic nucleus. When going to lighter masses, a surprisingly large and early departure from sphericity is observed, which is only partly reproduced by beyond mean field calculations.

  • 330.
    Colarieti-Tosti, Massimiliano
    et al.
    Department of Physics, Uppsala University.
    Katsnelson, M. I.
    Department of Physics, Uppsala University.
    Mattesini, M.
    Department of Physics, Uppsala University.
    Simak, S. I.
    Department of Physics, Uppsala University.
    Ahuja, Rajeev
    Department of Physics, Uppsala University.
    Johansson, Börje
    Department of Physics, Uppsala University.
    Dallera, C.
    INFM, Dipartimento di Fisica, Politecnico di Milano.
    Eriksson, O.
    Department of Physics, Uppsala University.
    First-principles theory of intermediate-valence f-electron systems2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 9, p. 096403-Article in journal (Refereed)
    Abstract [en]

    We propose a first-principles based method for calculating the electronic structure and total energy of solids in an intermediate-valence configuration. The method takes into account correlation effects (d-f Coulomb interaction) and many-body renormalization of the effective hybridization parameter of the f system. As an example, the formation of a pressure-induced intermediate-valence state in Yb is considered and its electronic structure and equation of state are calculated and compared to experimental data. The agreement is found to be excellent for both properties, and we argue that the developed method, which applies to any element or compound, provides for the first time a quantitative theoretical treatment of intermediate-valence materials.

  • 331.
    Cordero-Edwards, Kumara
    et al.
    CSIC, Catalan Inst Nanosci & Nanotechnol, Campus UAB, Barcelona 08193, Spain.;BIST, Campus UAB, Barcelona 08193, Spain.;Univ Geneva, DPMC MaNEP, Quai Ernest Ansermet 24, CH-1211 Geneva, Switzerland..
    Kianirad, Hoda
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Sort, Jordi
    UAB, Dept Fis, Edifici Cc, E-08193 Bellaterra, Spain.;ICREA, Pg Lluis Co 23, E-08010 Barcelona, Catalonia, Spain..
    Catalan, Gustau
    CSIC, Catalan Inst Nanosci & Nanotechnol, Campus UAB, Barcelona 08193, Spain.;BIST, Campus UAB, Barcelona 08193, Spain.;ICREA, Pg Lluis Co 23, E-08010 Barcelona, Catalonia, Spain..
    Flexoelectric Fracture-Ratchet Effect in Ferroelectrics2019In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, no 13, article id 135502Article in journal (Refereed)
    Abstract [en]

    The propagation front of a crack generates large strain gradients and it is therefore a strong source of gradient-induced polarization (flexoelectricity). Herein, we demonstrate that, in piezoelectric materials, a consequence of flexoelectricity is that crack propagation is helped or hindered depending on whether it is parallel or antiparallel to the piezoelectric polar axis. The discovery of crack propagation asymmetry proves that fracture physics cannot be assumed to be symmetric in polar materials, and indicates that flexoelectricity should be incorporated in any realistic model.

  • 332.
    Corlevi, Silvia
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Guichard, Wiebke
    KTH, School of Engineering Sciences (SCI), Physics.
    Hekking, Frank W. J.
    KTH, School of Engineering Sciences (SCI), Physics.
    Haviland, David B.
    KTH, School of Engineering Sciences (SCI), Physics.
    Phase-Charge duality of a Josephson junction in a fluctuating electromagnetic environment2006In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 97, no 9Article in journal (Refereed)
    Abstract [en]

    We have measured the current-voltage characteristics of a single Josephson junction placed in a high impedance environment. The transfer of Cooper pairs through the junction is governed by overdamped quasicharge dynamics, leading to Coulomb blockade and Bloch oscillations. Exact duality exists to the standard overdamped phase dynamics of a Josephson junction, resulting in a dual shape of the current-voltage characteristic, with current and voltage changing roles. We demonstrate this duality with experiments which allow for a quantitative comparison with a theory that includes the effect of fluctuations due to the finite temperature of the electromagnetic environment.

  • 333. Costa, Pedro
    et al.
    Picano, Francesco
    Brandt, Luca
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, Centres, SeRC - Swedish e-Science Research Centre. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Breugem, Wim-Paul
    Universal Scaling Laws for Dense Particle Suspensions in Turbulent Wall-Bounded Flows2016In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 117, no 13, article id 134501Article in journal (Refereed)
    Abstract [en]

    The macroscopic behavior of dense suspensions of neutrally buoyant spheres in turbulent plane channel flow is examined. We show that particles larger than the smallest turbulence scales cause the suspension to deviate from the continuum limit in which its dynamics is well described by an effective suspension viscosity. This deviation is caused by the formation of a particle layer close to the wall with significant slip velocity. By assuming two distinct transport mechanisms in the near-wall layer and the turbulence in the bulk, we define an effective wall location such that the flow in the bulk can still be accurately described by an effective suspension viscosity. We thus propose scaling laws for the mean velocity profile of the suspension flow, together with a master equation able to predict the increase in drag as a function of the particle size and volume fraction.

  • 334. Costi, T. A.
    et al.
    Bergqvist, Lars
    Institut für Festkörperforschung, Forschungszentrum Jülich.
    Weichselbaum, A.
    von Delft, J.
    Micklitz, T.
    Rosch, A.
    Mavropoulos, P.
    Dederichs, Peter. H.
    Mallet, F.
    Saminadayar, L.
    Bäuerle, C.
    Kondo Decoherence: Finding the Right Spin Model for Iron Impurities in Gold and Silver2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, no 5, p. 056802-Article in journal (Refereed)
    Abstract [en]

    We exploit the decoherence of electrons due to magnetic impurities, studied via weak localization, to resolve a long-standing question concerning the classic Kondo systems of Fe impurities in the noble metals gold and silver: which Kondo-type model yields a realistic description of the relevant multiple bands, spin, and orbital degrees of freedom? Previous studies suggest a fully screened spin S Kondo model, but the value of S remained ambiguous. We perform density functional theory calculations that suggest S=3/2. We also compare previous and new measurements of both the resistivity and decoherence rate in quasi-one-dimensional wires to numerical renormalization group predictions for S=1/2, 1, and 3/2, finding excellent agreement forS=3/2.

  • 335.
    Cozzani, G.
    et al.
    Swedish Inst Space Phys, S-75121 Uppsala, Sweden..
    Khotyaintsev, Yu., V
    Swedish Inst Space Phys, S-75121 Uppsala, Sweden..
    Graham, D. B.
    Swedish Inst Space Phys, S-75121 Uppsala, Sweden..
    Egedal, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA..
    Andre, M.
    Swedish Inst Space Phys, S-75121 Uppsala, Sweden..
    Vaivads, Andris
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Space and Plasma Physics.
    Alexandrova, A.
    Univ Paris Saclay, Sorbonne Univ, Lab Phys Plasmas, CNRS,Observ Paris,Ecole Polytech,Inst Polytech Pa, F-91128 Palaiseau, France..
    Le Contel, O.
    Univ Paris Saclay, Sorbonne Univ, Lab Phys Plasmas, CNRS,Observ Paris,Ecole Polytech,Inst Polytech Pa, F-91128 Palaiseau, France..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX 78238 USA.;Univ Texas San Antonio, San Antonio, TX 78249 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Structure of a Perturbed Magnetic Reconnection Electron Diffusion Region in the Earth's Magnetotail2021In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 127, no 21, article id 215101Article in journal (Refereed)
    Abstract [en]

    We report in situ observations of an electron diffusion region (EDR) and adjacent separatrix region in the Earth's magnetotail. We observe significant magnetic field oscillations near the lower hybrid frequency which propagate perpendicularly to the reconnection plane. We also find that the strong electron-scale gradients close to the EDR exhibit significant oscillations at a similar frequency. Such oscillations are not expected for a crossing of a steady 2D EDR, and can be explained by a complex motion of the reconnection plane induced by current sheet kinking propagating in the out-of-reconnection-plane direction. Thus, all three spatial dimensions have to be taken into account to explain the observed perturbed EDR crossing. These results shed light on the interplay between magnetic reconnection and current sheet drift instabilities in electron-scale current sheets and highlight the need for adopting a 3D description of the EDR, going beyond the two-dimensional and steady-state conception of reconnection.

  • 336. Crespi, F. C. L.
    et al.
    Bracco, A.
    Nicolini, R.
    Mengoni, D.
    Pellegri, L.
    Lanza, E. G.
    Leoni, S.
    Maj, A.
    Kmiecik, M.
    Avigo, R.
    Benzoni, G.
    Blasi, N.
    Boiano, C.
    Bottoni, S.
    Brambilla, S.
    Camera, F.
    Ceruti, S.
    Giaz, A.
    Million, B.
    Morales, A. I.
    Vandone, V.
    Wieland, O.
    Bednarczyk, P.
    Ciemala, M.
    Grebosz, J.
    Krzysiek, M.
    Mazurek, K.
    Zieblinski, M.
    Bazzacco, D.
    Bellato, M.
    Birkenbach, B.
    Bortolato, D.
    Calore, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Charles, L.
    de Angelis, G.
    Desesquelles, P.
    Eberth, J.
    Farnea, E.
    Gadea, A.
    Gorgen, A.
    Gottardo, A.
    Isocrate, R.
    Jolie, J.
    Jungclaus, A.
    Karkour, N.
    Korten, W.
    Menegazzo, R.
    Michelagnoli, C.
    Molini, P.
    Napoli, D. R.
    Pullia, A.
    Recchia, F.
    Reiter, P.
    Rosso, D.
    Sahin, E.
    Salsac, M. D.
    Siebeck, B.
    Siem, S.
    Simpson, J.
    Söderström, P. -A
    Stezowski, O.
    Theisen, Ch.
    Ur, C.
    Valiente-Dobon, J. J.
    Isospin Character of Low-Lying Pygmy Dipole States in Pb-208 via Inelastic Scattering of O-17 Ions2014In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 113, no 1, p. 012501-Article in journal (Refereed)
    Abstract [en]

    The properties of pygmy dipole states in Pb-208 were investigated using the Pb-208(O-17, O-17'gamma) reaction at 340 MeV and measuring the gamma decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted gamma rays and of the scattered particles were measured. The results are compared with (gamma, gamma') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2(+) and 3(-) states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1(-) excited states from 4 to 8 MeV.

  • 337.
    Cui, Jun Jie
    et al.
    School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China.
    Cheng, Yongjun
    School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China.
    Wang, Xin
    School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China.
    Li, Zheng
    State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China, Shanxi; Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China.
    Rohringer, Nina
    Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany.
    Kimberg, Victor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Theoretical Chemistry and Biology.
    Zhang, Song Bin
    School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China.
    Proposal for Observing XUV-Induced Rabi Oscillation Using Superfluorescent Emission2023In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 131, no 4, article id 043201Article in journal (Refereed)
    Abstract [en]

    Intense x-ray and extreme ultraviolet (XUV) light sources have been available for decades, however, due to weak nonlinear interaction in the XUV photon energy range, observation of Rabi oscillation induced by XUV pulse remains a very challenging experimental task. Here we suggest a scheme where photoionization of a He medium by an intense XUV pump pulse is followed by a strong population inversion and Rabi oscillation at the He+(1s-3p) transition and is accompanied by superfluorescence (SF) of the 7.56 eV pulse at the He+(3p-2s) transition. Our numerical simulations show that the Rabi oscillation at the He+(1s-3p) transition induced by an XUV pulse with photon energy 48.36 eV results in significant signatures in the SF spectra, allowing us to identify and characterize the XUV induced Rabi-oscillatory regime. The proposed scheme provides a sensitive tool to monitor and control ultrafast nonlinear dynamics in atoms and molecules triggered by intense XUV.

  • 338. Dahl, E. K.
    et al.
    Babaev, Egor
    Sudbo, A.
    Unusual States of Vortex Matter in Mixtures of Bose-Einstein Condensates on Rotating Optical Lattices2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 25Article in journal (Refereed)
    Abstract [en]

    In a single-component superfluid under rotation a broken symmetry in the order parameter space results in a broken translational symmetry in real space: a vortex lattice. If translational symmetry is restored, the phase of the order parameter disorders and thus the broken symmetry in the order parameter space is also restored. We show that for Bose-Einstein condensate mixtures in optical lattices with negative dissipationless drag, a new situation arises. This state is a modulated vortex liquid which breaks translational symmetry in the direction transverse to the rotation vector.

  • 339.
    Das, Adway Kumar
    et al.
    Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 India.
    Ghosh, Anandamohan
    Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 India.
    Khaymovich, Ivan M.
    Nordita SU; Institute for Physics of Microstructures, Russian Academy of Sciences, 603950 Nizhny Novgorod, GSP-105, Russia.
    Absence of Mobility Edge in Short-Range Uncorrelated Disordered Model: Coexistence of Localized and Extended States2023In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 131, no 16, article id 166401Article in journal (Refereed)
    Abstract [en]

    Unlike the well-known Mott's argument that extended and localized states should not coexist at the same energy in a generic random potential, we formulate the main principles and provide an example of a nearest-neighbor tight-binding disordered model which carries both localized and extended states without forming the mobility edge. Unexpectedly, this example appears to be given by a well-studied β ensemble with independently distributed random diagonal potential and inhomogeneous kinetic hopping terms. In order to analytically tackle the problem, we locally map the above model to the 1D Anderson model with matrix-size- and position-dependent hopping and confirm the coexistence of localized and extended states, which is shown to be robust to the perturbations of both potential and kinetic terms due to the separation of the above states in space. In addition, the mapping shows that the extended states are nonergodic and allows one to analytically estimate their fractal dimensions.

  • 340.
    Davison, Richard A.
    et al.
    Harvard Univ, Dept Phys, Cambridge, MA 02138 USA.;Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 0WA, England..
    Gentle, Simon A.
    Univ Utrecht, Inst Theoret Phys, NL-3508 TD Utrecht, Netherlands.;Leiden Univ, Inst Lorentz Theoret Phys, NL-2333 CA Leiden, Netherlands..
    Goutéraux, Blaise
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA. Stockholm Univ, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden..
    Slow Relaxation and Diffusion in Holographic Quantum Critical Phases2019In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 14, article id 141601Article in journal (Refereed)
    Abstract [en]

    The dissipative dynamics of strongly interacting systems are often characterized by the timescale set by the inverse temperature tau(p) similar to h/(k(B)T). We show that near a class of strongly interacting quantum critical points that arise in the infrared limit of translationally invariant holographic theories, there is a collective excitation (a quasinormal mode of the dual black hole spacetime) whose lifetime tau(eq) is parametrically longer than tau(p): tau(eq) >> T-1. The lifetime is enhanced due to its dependence on a dangerously irrelevant coupling that breaks the particle-hole symmetry and the invariance under Lorentz boosts of the quantum critical point. The thermal diffusivity (in units of the butterfly velocity) is anomalously large near the quantum critical point and is governed by tau(eq) rather than tau(p). We conjecture that there exists a long-lived, propagating collective mode with velocity v(s), and in this case the relation D = v(s)(2)tau(eq) holds exactly in the limit T tau(eq) >> 1. While scale invariance is broken, a generalized scaling theory still holds provided that the dependence of observables on the dangerously irrelevant coupling is incorporated. Our work further underlines the connection between dangerously irrelevant deformations and slow equilibration.

  • 341. Deca, J.
    et al.
    Divin, A.
    Lapenta, G.
    Lembège, B.
    Markidis, Stefano
    KTH, School of Computer Science and Communication (CSC), High Performance Computing and Visualization (HPCViz).
    Horányi, M.
    Electromagnetic Particle-in-Cell Simulations of the Solar Wind Interaction with Lunar Magnetic Anomalies2014In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 112, no 15, p. 151102-Article in journal (Refereed)
    Abstract [en]

    We present the first three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal magnetic anomalies (LMAs). Using the implicit particle-in-cell code IPIC3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier magnetohydrodynamics and hybrid simulations, the fully kinetic nature of IPIC3D allows us to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe for the first time the interaction of a dipole model centered just below the lunar surface under plasma conditions such that only the electron population is magnetized. The fully kinetic treatment identifies electromagnetic modes that alter the magnetic field at scales determined by the electron physics. Driven by strong pressure anisotropies, the mini-magnetosphere is unstable over time, leading to only temporal shielding of the surface underneath. Future human exploration as well as lunar science in general therefore hinges on a better understanding of LMAs.

  • 342. Deca, Jan
    et al.
    Divin, Andrey
    Henri, Pierre
    Eriksson, Anders
    Markidis, Stefano
    KTH, School of Computer Science and Communication (CSC), Computational Science and Technology (CST).
    Olshevsky, Vyacheslav
    Horanyi, Mihaly
    Electron and Ion Dynamics of the Solar Wind Interaction with a Weakly Outgassing Comet2017In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 118, no 20, article id 205101Article in journal (Refereed)
    Abstract [en]

    Using a 3D fully kinetic approach, we disentangle and explain the ion and electron dynamics of the solar wind interaction with a weakly outgassing comet. We show that, to first order, the dynamical interaction is representative of a four-fluid coupled system. We self-consistently simulate and identify the origin of the warm and suprathermal electron distributions observed by ESA's Rosetta mission to comet 67P/Churyumov-Gerasimenko and conclude that a detailed kinetic treatment of the electron dynamics is critical to fully capture the complex physics of mass-loading plasmas.

  • 343.
    Delafosse, C.
    et al.
    Univ Paris Saclay, Univ Paris Sud, CNRS IN2P3, Inst Phys Nucl, F-91406 Orsay, France..
    Verney, D.
    Univ Paris Saclay, Univ Paris Sud, CNRS IN2P3, Inst Phys Nucl, F-91406 Orsay, France..
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dobon, J. J. Valiente
    Inst Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the Ni-78 Region: A Hint from Lifetime Measurements2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 121, no 19, article id 192502Article in journal (Refereed)
    Abstract [en]

    Lifetime measurements of excited states of the light N = 52 isotones Kr-88, Se-86, and Ge-84 have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2; 2(+)-> 0(+)) and B(E2; 4(+)-> 2(+)) were obtained for the first time for the hard-to-reach 84Ge. While the B(E2; 2(+)-> 0(+) ) values of Kr-88, Se-86 saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g(7/2), 1h(11/2)) space of an inert Ni-78 core, the value obtained for Ge-84 largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N less than or similar to 49, extend beyond N = 50. The onset of collectivity at Z = 32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector rho field in shell-structure evolution.

  • 344.
    Delin, Anna
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Tosatti, E.
    Weht, R.
    Delin, Tosatti, and Weht Reply2006In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, no 7Article in journal (Refereed)
  • 345.
    Delin, Anna
    et al.
    ICTP, Trieste, Italy.
    Tosatti, Erio
    ICTP, Trieste, Italy.
    Weht, Ruben
    Comis Nacl Energia Atom, Dept Fis, RA-1650 San Martin, Argentina.
    Magnetism in atomic-size palladium contacts and nanowires2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 5, p. 057201-572014Article in journal (Refereed)
    Abstract [en]

    Palladium (Pd) nanowires, that exhibit Hund's rule magnetism are investigated. A spin moment of 0.7μB per atom is found in long, monostrand nanowires. The predicted moment is about 0.3μB per nanowire atom for short, monostrand nanowires between bulk leads. Results show that a coaxial (6,1) nanowire was nonmagnetic in nature.

  • 346. Delion, D. S.
    et al.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Systematics of proton emission2006In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, no 7, p. 072501-Article in journal (Refereed)
    Abstract [en]

    A very simple formula is presented that relates the logarithm of the half-life, corrected by the centrifugal barrier, with the Coulomb parameter in proton decay processes. The corresponding experimental data lie on two straight lines which appear as a result of a sudden change in the nuclear shape marking two regions of deformation independently of the angular momentum of the outgoing proton. This feature provides a powerful tool to assign experimentally quantum numbers in proton emitters.

  • 347.
    Dendzik, Maciej
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Xian, R. Patrick
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Perfetto, Enrico
    CNR ISM, Div Ultrafast Proc Mat FLASHit, Area Ric Roma 1,Via Solaria Km 29-3, I-00016 Monterotondo, Italy.;Tor Vergata Univ Rome, Dept Phys, Via Ric Sci 1, I-00133 Rome, Italy..
    Sangalli, Davide
    CNR ISM, Div Ultrafast Proc Mat FLASHit, Area Ric Roma 1,Via Solaria Km 29-3, I-00016 Monterotondo, Italy.;Univ Milan, Dept Phys, Via Celoria 16, I-20133 Milan, Italy..
    Kutnyakhov, Dmytro
    DESY Photon Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Dong, Shuo
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Beaulieu, Samuel
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Pincelli, Tommaso
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Pressacco, Federico
    Hamburg Univ, Ctr Free Electron Laser Sci CFEL, Luruper Chausee 149, D-22761 Hamburg, Germany..
    Curcio, Davide
    Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Dept Phys & Astron, Ny Munkegade 120, DK-8000 Aarhus C, Denmark..
    Agustsson, Steinn Ymir
    Johannes Gutenberg Univ Mainz, Inst Phys, D-55128 Mainz, Germany..
    Heber, Michael
    DESY Photon Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Hauer, Jasper
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Wurth, Wilfried
    DESY Photon Sci, Notkestr 85, D-22607 Hamburg, Germany.;Hamburg Univ, Ctr Free Electron Laser Sci CFEL, Luruper Chausee 149, D-22761 Hamburg, Germany..
    Brenner, Guenter
    DESY Photon Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Acremann, Yves
    Swiss Fed Inst Technol, Dept Phys, Lab Solid State Phys, Otto Stern Weg 1, CH-8093 Zurich, Switzerland..
    Hofmann, Philip
    Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Dept Phys & Astron, Ny Munkegade 120, DK-8000 Aarhus C, Denmark..
    Wolf, Martin
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Marini, Andrea
    CNR ISM, Div Ultrafast Proc Mat FLASHit, Area Ric Roma 1,Via Solaria Km 29-3, I-00016 Monterotondo, Italy..
    Stefanucci, Gianluca
    Tor Vergata Univ Rome, Dept Phys, Via Ric Sci 1, I-00133 Rome, Italy.;Ist Nazl Fis Nucl, Sez Roma Tor Vergata, Via Ric Sci 1, I-00133 Rome, Italy..
    Rettig, Laurenz
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Ernstorfer, Ralph
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14915 Berlin, Germany..
    Observation of an Excitonic Mott Transition Through Ultrafast Core-cum-Conduction Photoemission Spectroscopy2020In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 125, no 9, article id 096401Article in journal (Refereed)
    Abstract [en]

    Time-resolved soft-x-ray photoemission spectroscopy is used to simultaneously measure the ultrafast dynamics of core-level spectral functions and excited states upon excitation of excitons in WSe2. We present a many-body approximation for the Green's function, which excellently describes the transient core-hole spectral function. The relative dynamics of excited-state signal and core levels clearly show a delayed core-hole renormalization due to screening by excited quasifree carriers resulting from an excitonic Mott transition. These findings establish time-resolved core-level photoelectron spectroscopy as a sensitive probe of subtle electronic many-body interactions and ultrafast electronic phase transitions.

  • 348.
    Deng, Jian
    et al.
    Zhejiang Univ, Dept Mech, State Key Lab Fluid Power & Mechatron Syst, Hangzhou 310027, Peoples R China..
    Mao, Xuerui
    Univ Nottingham, Fac Engn, Univ Pk, Nottingham NG7 2RD, England..
    Brandt, Luca
    KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Symmetry Breaking of Tail-Clamped Filaments in Stokes Flow2021In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 126, no 12, article id 124501Article in journal (Refereed)
    Abstract [en]

    Symmetry breaking (SB) of fluid-structure interaction problems plays an important role in our understanding of animals' locomotive and sensing behaviors. In this Letter, we study the SB of flexible filaments clamped at one end and placed in a spanwise periodic array in Stokes flow. The equilibrium state of the filament along the streamwise direction loses stability and experiences two-dimensional and then three-dimensional SBs as the spanwise distance increases, or as the filament rigidity reduces. For slightly deformed filaments, the viscous and pressure forces are commensurate, while for extremely deformed filaments the viscous force becomes dominant.

  • 349. Dewhurst, J. K.
    et al.
    Ahuja, Rajeev
    Li, S.
    Johansson, Börje
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Lattice dynamics of solid xenon under pressure2002In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 88, no 7Article in journal (Refereed)
    Abstract [en]

    We use density-functional perturbation theory to obtain the phonon spectrum of fcc xenon under pressure. Thermodynamic properties obtained within the quasiharmonic approximation are in fair to good agreement with experiment at zero pressure. The transition pressure from the fcc to hcp phase is predicted to occur at 5 GPa. The fcc structure is found to be dynamically stable up to a pressure of 100 GPa, beyond which the phonon modes at the X and L symmetry points soften. We attribute the observed sluggish kinetics of the fcc-hcp transition to the small energy difference between the phases as well as to the high dynamical stability of the fcc phase.

  • 350. Diaz, C
    et al.
    Vincent, Jonathan
    Krishnamohan, G.P.
    Olsen, R.A.
    Kroes, G.J.
    Honkala, K
    Nørskov, J
    Multidimensional effects on dissociation of N2 on Ru(0001)2006In: Physical Review Letters, ISSN 0031-9007, Vol. 96, no 9, p. 096102-Article in journal (Refereed)
    Abstract [en]

    The applicability of the Born-Oppenheimer approximation to molecule-metal surface reactions is presently a topic of intense debate. We have performed classical trajectory calculations on a prototype activated dissociation reaction, of N2 on Ru(0001), using a potential energy surface based on density functional theory. The computed reaction probabilities are in good agreement with molecular beam experiments. Comparison to previous calculations shows that the rotation of N2 and its motion along the surface affect the reactivity of N2 much more than nonadiabatic effects.

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