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  • 1.
    Banerjee, Saikat
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Interacting Dirac Matter2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The discovery of graphene in 2004 has led to a surge of activities focused on the theoretical and experimental studies of materials hosting linearly dispersive quasiparticles during the last decade. Rapid expansion in the list of materials having similar properties to graphene has led to the emergence of a new class of materials known as the Dirac materials. The low energy quasiparticles in this class of materials are described by a Dirac-like equation in contrast to the Schrödinger equation which governs the low energy dynamics in any conventional materials such as metals. The Dirac fermions, as we call these low-energy quasiparticles, in a wide range of materials ranging from the d-wave superconductors, graphene to the surface states of topological insulators share the common property. The particles move around as if they have lost their mass. This feature results in a completely new set of physical effects consisting of various transport and thermodynamic quantities, that are absent in conventional metals.

    This thesis is devoted to studying the properties of bosonic analogs of the commonly known Dirac materials where the quasiparticle are fermionic. In chapter one, we discuss the microscopic origin of the Dirac equation in several fermionic and bosonic systems. We observe identical features of the Dirac materials with quasiparticles of either statistics when the interparticle interaction is absent. Dirac materials with both types of quasiparticles possess the nodal excitations that are described by an effective Dirac-like equation. The possible physical effects due to the linear dispersions in fermionic and bosonic Dirac materials are also outlined.

    In chapter two, we propose a system of superconducting grains arranged in honeycomb lattice as a realization for Bosonic Dirac Materials (BDM). The underlying microscopic dynamics, which give rise to the emergence of Dirac structure in the spectrum of the collective phase oscillations, is discussed in detail. Similarities and differences of BDM systems to the conventional Dirac materials with fermionic quasiparticles are also mentioned. Chapter three is dedicated to the detailed analysis of the interaction effects on the stability and renormalization of the conical Dirac band structure. We find that the type of interaction dictates the possible fate of renormalized Dirac cone in both fermionic and bosonic Dirac materials. We study interaction effects in four different individual systems : (a) Dirac fermions in graphene interacting via Coulomb interactions, (b) Dirac fermions subjected to an onsite Hubbard repulsion, (c) Coulomb repulsion in charged Cooper pairs in honeycomb lattice and (d) Dirac magnons interacting via Heisenberg exchange interaction. The possibility of interaction induced gap opening at the Dirac nodal point described is also discussed in these cases.

    Chapter four mainly concerns the study of a related topic of the synthetic gauge fields. We discuss the possibility of Landau quantization in neutral particles. Possible experimental evidence in toroidal cold atomic traps is also mentioned. A connection to Landau levels in case of magnons is also described. We finally conclude our thesis in chapter five and discuss the possible future directions that can be taken as an extension for our works in interacting Dirac materials.

  • 2.
    Barkman, Mats
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Zyuzin, Alexander A.
    Aalto Univ, Dept Appl Phys, POB 15100, FI-00076 Aalto, Finland.;Ioffe Phys Tech Inst, St Petersburg 194021, Russia..
    Babaev, Egor
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Antichiral and nematicity-wave superconductivity2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 22, artikkel-id 220508Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Larkin-Ovchinnikov superconducting state has spontaneous modulation of Cooper pair density, while Fulde-Ferrell state has a spontaneous modulation in the phase of the order parameter. We report that a quasi-two-dimensional Dirac metal, under certain conditions has principally different inhomogeneous superconducting states that by contrast have spontaneous modulation in a submanifold of a multiple-symmetries-breaking order parameter. The first state we find can be viewed as a nematic superconductor where the nematicity vector spontaneously breaks rotational and translational symmetries due to spatial modulation. The other demonstrated state is a chiral superconductor with spontaneously broken time-reversal and translational symmetries. It is characterized by an order parameter, which forms a lattice pattern of alternating chiralities.

  • 3. Behrends, Jan
    et al.
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Max Planck Institute, Germany.
    Strongly angle-dependent magnetoresistance in Weyl semimetals with long-range disorder2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 6, artikkel-id 060201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The chiral anomaly in Weyl semimetals states that the left- and right-handed Weyl fermions, constituting the low energy description, are not individually conserved, resulting, for example, in a negative magnetoresistance in such materials. Recent experiments see strong indications of such an anomalous resistance response; however, with a response that at strong fields is more sharply peaked for parallel magnetic and electric fields than expected from simple theoretical considerations. Here, we uncover a mechanism, arising from the interplay between the angle-dependent Landau-level structure and long-range scalar disorder, that has the same phenomenology. In particular, we analytically show, and numerically confirm, that the internode scattering time decreases exponentially with the angle between the magnetic field and the Weyl node separation in the large field limit, while it is insensitive to this angle at weak magnetic fields. Since, in the simplest approximation, the internode scattering time is proportional to the anomaly-related conductivity, this feature may be related to the experimental observations of a sharply peaked magnetoresistance.

  • 4. Behrends, Jan
    et al.
    Rhim, Jun-Won
    Liu, Shang
    Grushin, Adolfo G.
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Max-Planck-Institut für Physik Komplexer Systeme, Germany.
    Nodal-line semimetals from Weyl superlattices2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 24, artikkel-id 245101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The existence and topological classification of lower-dimensional Fermi surfaces is often tied to the crystal symmetries of the underlying lattice systems. Artificially engineered lattices, such as heterostructures and other superlattices, provide promising avenues to realize desired crystal symmetries that protect lower-dimensional Fermi surfaces, such as nodal lines. In this work, we investigate a Weyl semimetal subjected to spatially periodic onsite potential, giving rise to several phases, including a nodal-line semimetal phase. In contrast to proposals that purely focus on lattice symmetries, the emergence of the nodal line in this setup does not require small spin-orbit coupling, but rather relies on its presence. We show that the stability of the nodal line is understood from reflection symmetry and a combination of a fractional lattice translation and charge-conjugation symmetry. Depending on the choice of parameters, this model exhibits drumhead surface states that are exponentially localized at the surface, or weakly localized surface states that decay into the bulk at all energies.

  • 5.
    Behrends, Jan
    et al.
    Max Planck Inst Phys Komplexer Systeme, D-01187 Dresden, Germany..
    Roy, Sthitadhi
    Max Planck Inst Phys Komplexer Systeme, D-01187 Dresden, Germany.;Univ Oxford, Phys & Theoret Chem, South Parks Rd, Oxford OX1 3QZ, England.;Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England..
    Kolodrubetz, Michael H.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;Lawrence Berkeley Natl Lab, Mat Sci Div, Berkeley, CA 94720 USA.;Univ Texas Dallas, Dept Phys, Richardson, TX 75080 USA..
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Max Planck Inst Phys Komplexer Systeme, D-01187 Dresden, Germany.
    Grushin, Adolfo G.
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA.;CNRS, Inst Neel, F-38042 Grenoble, France.;Univ Grenoble Alpes, F-38042 Grenoble, France..
    Landau levels, Bardeen polynomials, and Fermi arcs in Weyl semimetals: Lattice-based approach to the chiral anomaly2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 14, artikkel-id 140201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Condensed matter systems realizing Weyl fermions exhibit striking phenomenology derived from their topologically protected surface states as well as chiral anomalies induced by electromagnetic fields. More recently, inhomogeneous strain or magnetization were predicted to result in chiral electric E-5 and magnetic B-5 fields, which modify and enrich the chiral anomaly with additional terms. In this Rapid Communication, we develop a lattice-based approach to describe the chiral anomaly, which involves Landau and pseudo-Landau levels and treats all anomalous terms on equal footing, while naturally incorporating Fermi arcs. We exemplify its potential by physically interpreting the largely overlooked role of Fermi arcs in the covariant (Fermi level) contribution to the anomaly and revisiting the factor of 1/3 difference between the covariant and consistent (complete band) contributions to the E-5 . B-5 term in the anomaly. Our framework provides a versatile tool for the analysis of anomalies in realistic lattice models as well as a source of simple physical intuition for understanding strained and magnetized inhomogeneous Weyl semimetals.

  • 6.
    Belonoshko, Anatoly B.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Lukinov, Timofei
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Fu, Jie
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Zhao, Jijun
    Davis, Sergio
    Simak, Sergei I.
    Stabilization of body-centred cubic iron under inner-core conditions2017Inngår i: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 10, nr 4, s. 312-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Earth's solid core is mostly composed of iron. However, despite being central to our understanding of core properties, the stable phase of iron under inner-core conditions remains uncertain. The two leading candidates are hexagonal close-packed and body-centred cubic (bcc) crystal structures, but the dynamic and thermodynamic stability of bcc iron under inner-core conditions has been challenged. Here we demonstrate the stability of the bcc phase of iron under conditions consistent with the centre of the core using ab initio molecular dynamics simulations. We find that the bcc phase is stabilized at high temperatures by a diffusion mechanism that arises due to the dynamical instability of the phase at lower temperatures. On the basis of our simulations, we reinterpret experimental data as support for the stability of bcc iron under inner-core conditions. We suggest that the diffusion of iron atoms in solid state may explain both the anisotropy and the low shear modulus of the inner core.

  • 7.
    Belonoshko, Anatoly
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Fu, Jie
    Ningbo Univ, Dept Phys, Fac Sci, Ningbo 315211, Zhejiang, Peoples R China..
    Bryk, Taras
    Natl Acad Sci Ukraine, Inst Condensed Matter Phys, UA-79011 Lvov, Ukraine..
    Simak, Sergei, I
    Linkoping Univ, Dept Phys Chem & Biol IFM, SE-58183 Linkoping, Sweden..
    Mattesini, Maurizio
    Univ Complutense Madrid, Dept Earths Phys & Astrophys, E-28040 Madrid, Spain.;UCM, CSIC, Fac Ciencias Fis, Inst Geociencias, Plaza Ciencias 1, Madrid 28040, Spain..
    Low viscosity of the Earth's inner core2019Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikkel-id 2483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Earth's solid inner core is a highly attenuating medium. It consists mainly of iron. The high attenuation of sound wave propagation in the inner core is at odds with the widely accepted paradigm of hexagonal close-packed phase stability under inner core conditions, because sound waves propagate through the hexagonal iron without energy dissipation. Here we show by first-principles molecular dynamics that the body-centered cubic phase of iron, recently demonstrated to be thermodynamically stable under the inner core conditions, is considerably less elastic than the hexagonal phase. Being a crystalline phase, the body-centered cubic phase of iron possesses the viscosity close to that of a liquid iron. The high attenuation of sound in the inner core is due to the unique diffusion characteristic of the body-centered cubic phase. The low viscosity of iron in the inner core enables the convection and resolves a number of controversies.

  • 8. Bera, Soumya
    et al.
    Martynec, Thomas
    Schomerus, Henning
    Heidrich-Meisner, Fabian
    Hjörleifur Bardarson, Jens
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Max-Planck-Institut für Physik komplexer Systeme, Germany.
    One-particle density matrix characterization of many-body localization2017Inngår i: Annalen der Physik, ISSN 0003-3804, E-ISSN 1521-3889, Vol. 529, nr 7, artikkel-id 1600356Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study interacting fermions in one dimension subject to random, uncorrelated onsite disorder, a paradigmatic model of many-body localization (MBL). This model realizes an interaction-driven quantum phase transition between an ergodic and a many-body localized phase, with the transition occurring in the many-body eigenstates. We propose a single-particle framework to characterize these phases by the eigenstates (the natural orbitals) and the eigenvalues (the occupation spectrum) of the one-particle density matrix (OPDM) in individual many-body eigenstates. As a main result, we find that the natural orbitals are localized in the MBL phase, but delocalized in the ergodic phase. This qualitative change in these single-particle states is a many-body effect, since without interactions the single-particle energy eigenstates are all localized. The occupation spectrum in the ergodic phase is thermal in agreement with the eigenstate thermalization hypothesis, while in the MBL phase the occupations preserve a discontinuity at an emergent Fermi edge. This suggests that the MBL eigenstates are weakly dressed Slater determinants, with the eigenstates of the underlying Anderson problem as reference states. We discuss the statistical properties of the natural orbitals and of the occupation spectrum in the two phases and as the transition is approached. Our results are consistent with the existing picture of emergent integrability and localized integrals of motion, or quasiparticles, in the MBL phase. We emphasize the close analogy of the MBL phase to a zero-temperature Fermi liquid: in the studied model, the MBL phase is adiabatically connected to the Anderson insulator and the occupation-spectrum discontinuity directly indicates the presence of quasiparticles localized in real space. Finally, we show that the same picture emerges for interacting fermions in the presence of an experimentally-relevant bichromatic lattice and thereby demonstrate that our findings are not limited to a specific model.

  • 9.
    Bergqvist, Lars
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Eriksson, Olle
    Bergman, Anders
    Hellsvik, Johan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Atomistic Spin Dynamics: Foundations and Applications2017Bok (Annet vitenskapelig)
  • 10.
    Bommer, Jouri D. S.
    et al.
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands..
    Zhang, Hao
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands.;Tsinghua Univ, State Key Lab Low Dimens Quantum Phys, Dept Phys, Beijing 100084, Peoples R China..
    Gul, Onder
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands..
    Nijholt, Bas
    Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands..
    Wimmer, Michael
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands..
    Rybakov, Filipp N.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Statistisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Garaud, Julien
    Univ Tours, Lab Math & Phys Theor CNRS UMR 7350, Inst Denis Poisson FR2964, Parc Grandmt, F-37200 Tours, France..
    Rodic, Donjan
    Swiss Fed Inst Technol, Inst Theoret Phys, CH-8093 Zurich, Switzerland..
    Babaev, Egor
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Statistisk fysik. KTH Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden..
    Troyer, Matthias
    Swiss Fed Inst Technol, Inst Theoret Phys, CH-8093 Zurich, Switzerland.;Microsoft Quantum, Redmond, WA 98052 USA..
    Car, Diana
    Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands..
    Plissard, Sebastien R.
    Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands..
    Bakkers, Erik P. A. M.
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands.;Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands..
    Watanabe, Kenji
    Natl Inst Mat Sci, Adv Mat Lab, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan..
    Taniguchi, Takashi
    Natl Inst Mat Sci, Adv Mat Lab, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan..
    Kouwenhoven, Leo P.
    Delft Univ Technol, QuTech, NL-2600 GA Delft, Netherlands.;Delft Univ Technol, Kavli Inst Nanosci, NL-2600 GA Delft, Netherlands.;Microsoft Stn Q Delft, NL-2600 GA Delft, Netherlands..
    Spin-Orbit Protection of Induced Superconductivity in Majorana Nanowires2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, nr 18, artikkel-id 187702Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spin-orbit interaction (SOI) plays a key role in creating Majorana zero modes in semiconductor nanowires proximity coupled to a superconductor. We track the evolution of the induced superconducting gap in InSb nanowires coupled to a NbTiN superconductor in a large range of magnetic field strengths and orientations. Based on realistic simulations of our devices, we reveal SOI with a strength of 0.15-0.35 eV angstrom. Our approach identifies the direction of the spin-orbit field, which is strongly affected by the superconductor geometry and electrostatic gates.

  • 11. Bovo, L.
    et al.
    Twengström, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Petrenko, O. A.
    Fennell, T.
    Gingras, M. J. P.
    Bramwell, S. T.
    Henelius, P.
    Special temperatures in frustrated ferromagnets,Manuskript (preprint) (Annet vitenskapelig)
  • 12. Dufouleur, J.
    et al.
    Xypakis, E.
    Buechner, B.
    Giraud, R.
    Bardarson, Jens Hjörleifur
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Max Planck Institute for Physics - Max-Planck-Gesellschaft, Germany.
    Suppression of scattering in quantum confined 2D helical Dirac systems2018Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, nr 7, artikkel-id 075401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transport properties of helical Dirac fermions in disordered quantum wires are investigated in the large energy limit. In the quasiballistic regime, the conductance and the Fano factor are sensitive to disorder only when the Fermi energy is close to an opening of a transverse mode. In the limit of a large number of transverse modes, transport properties are insensitive to the geometry of the nanowire or the nature and strength of the disorder but, instead, are dominated by the properties of the interface between the ohmic contact and the nanowire. In the case of a heavily doped Dirac metallic contact, the conductance is proportional to the energy with an average transmission T = pi/4 and a Fano factor of F similar or equal to 0.13. Those results can be generalized to a much broader class of contacts, the exact values of T and F depending on the model used for the contacts. The energy dependence of Aharonov-Bohm oscillations is determined, revealing a damped oscillatory behavior and phase shifts due to the one-dimensional subband quantization and which are not the signature of the nontrivial topology.

  • 13.
    Edberg, Richard
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Sandberg, L. Orduk
    Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, Univ Pk 5, DK-2100 Copenhagen O, Denmark..
    Bakke, I. M. Bergh
    Univ Oslo, Ctr Mat Sci & Nanotechnol, N-0315 Oslo, Norway..
    Haubro, M. L.
    Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, Univ Pk 5, DK-2100 Copenhagen O, Denmark..
    Folkers, L. C.
    Lund Univ, Dept Chem, Lund, Sweden..
    Mangin-Thro, L.
    Inst Laue Langevin, F-38042 Grenoble, France..
    Wildes, A.
    Inst Laue Langevin, F-38042 Grenoble, France..
    Zaharko, O.
    Paul Scherrer Inst, Lab Neutron Scattering, CH-5232 Villigen, Switzerland..
    Guthrie, M.
    European Spallat Source ERIC, S-22363 Lund, Sweden.;Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland.;Univ Edinburgh, Ctr Sci Extreme Condit, Edinburgh, Midlothian, Scotland..
    Holmes, A. T.
    European Spallat Source ERIC, S-22363 Lund, Sweden..
    Sorby, M. H.
    Inst Energy Technol, Dept Neutron Mat Characterizat, POB 40, N-2027 Kjeller, Norway..
    Lefmann, K.
    Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, Univ Pk 5, DK-2100 Copenhagen O, Denmark..
    Deen, P. P.
    Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, Univ Pk 5, DK-2100 Copenhagen O, Denmark.;European Spallat Source ERIC, S-22363 Lund, Sweden..
    Henelius, Patrik
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Abo Akad Univ, Fac Sci & Engn, Turku, Finland..
    Dipolar spin ice under uniaxial pressure2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 100, nr 14, artikkel-id 144436Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The magnetically frustrated spin ice family of materials is host to numerous exotic phenomena such as magnetic monopole excitations and macroscopic residual entropy extending to low temperature. A finite-temperature ordering transition in the absence of applied fields has not been experimentally observed in the classical spin ice materials Dy2Ti2O7 and Ho2Ti2O7. Such a transition could be induced by the application of pressure, and in this work we consider the effects of uniaxial pressure on classical spin ice systems. Theoretically, we find that the pressure-induced ordering transition in Dy2Ti2O7 is strongly affected by the dipolar interaction. We also report measurements of the neutron structure factor of Ho2Ti2O7 under pressure and compare the experimental results to the predictions of our theoretical model.

  • 14. Erlingsson, Sigurdur I.
    et al.
    Manolescu, Andrei
    Nemnes, George Alexandru
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Sanchez, David
    Reversal of Thermoelectric Current in Tubular Nanowires2017Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 119, nr 3, artikkel-id 036804Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We calculate the charge current generated by a temperature bias between the two ends of a tubular nanowire. We show that in the presence of a transversal magnetic field the current can change sign; i.e., electrons can either flow from the hot to the cold reservoir, or in the opposite direction, when the temperature bias increases. This behavior occurs when the magnetic field is sufficiently strong, such that Landau and snaking states are created, and the energy dispersion is nonmonotonic with respect to the longitudinal wave vector. The sign reversal can survive in the presence of impurities. We predict this result for core-shell nanowires, for uniform nanowires with surface states due to the Fermi level pinning, and for topological insulator nanowires.

  • 15. Farrokh, Atai
    et al.
    Hallnas, Martin
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Orthogonality of super‐Jack polynomials and a Hilbert space interpretation of deformed Calogero–Moser–Sutherland operators2019Inngår i: Bulletin of the London Mathematical Society, ISSN 0024-6093, E-ISSN 1469-2120, Vol. 51, nr 2, s. 353-370Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We prove orthogonality and compute explicitly the (quadratic) norms for super-Jack polynomials SP lambda((z1, horizontal ellipsis ,zn),(w1, horizontal ellipsis ,wm);theta) with respect to a natural positive semi-definite, but degenerate, Hermitian product ⟨center dot,center dot⟩n,m,theta '. In case m=0 (or n=0), our product reduces to Macdonald's well-known inner product ⟨center dot,center dot⟩n,theta ', and we recover his corresponding orthogonality results for the Jack polynomials P lambda((z1, horizontal ellipsis ,zn);theta). From our main results, we readily infer that the kernel of ⟨center dot,center dot⟩n,m,theta ' is spanned by the super-Jack polynomials indexed by a partition lambda not containing the mxn rectangle (mn). As an application, we provide a Hilbert space interpretation of the deformed trigonometric Calogero-Moser-Sutherland operators of type A(n-1,m-1).

  • 16.
    Ferreiros, Yago
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Vozmediano, Maria A. H.
    Elastic gauge fields and Hall viscosity of Dirac magnons2018Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, nr 5, artikkel-id 054404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze the coupling of elastic lattice deformations to the magnon degrees of freedom of magnon Dirac materials. For a honeycomb ferromagnet we find that, as happens in the case of graphene, elastic gauge fields appear coupled to the magnon pseudospinors. For deformations that induce constant pseudomagnetic fields, the spectrum around the Dirac nodes splits into pseudo-Landau levels. We show that when a Dzyaloshinskii-Moriya interaction is considered, a topological gap opens in the system and a Chern-Simons effective action for the elastic degrees of freedom is generated. Such a term encodes a phonon Hall viscosity response, entirely generated by quantum fluctuations of magnons living in the vicinity of the Dirac points. The magnon Hall viscosity vanishes at zero temperature, and grows as temperature is raised and the states around the Dirac points are increasingly populated.

  • 17.
    Ferreiros, Yago
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Zyuzin, A. A.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Bardarson, Jens H
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Anomalous Nernst and thermal Hall effects in tilted Weyl semimetals2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 11, artikkel-id 115202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the anomalous Nernst and thermal Hall effects in a linearized low-energy model of a tilted Weyl semimetal, with two Weyl nodes separated in momentum space. For inversion symmetric tilt, we give analytic expressions in two opposite limits: For a small tilt, corresponding to a type-I Weyl semimetal, the Nernst conductivity is finite and independent of the Fermi level; for a large tilt, corresponding to a type-II Weyl semimetal, it acquires a contribution depending logarithmically on the Fermi energy. This result is in a sharp contrast to the nontilted case, where the Nernst response is known to be zero in the linear model. The thermal Hall conductivity similarly acquires Fermi surface contributions, which add to the Fermi level-independent, zero-tilt result, and is suppressed as one over the tilt parameter at half filling in the type-II phase. In the case of inversion-breaking tilt, with the tilting vector of equal modulus in the two Weyl cones, all Fermi surface contributions to both anomalous responses cancel out, resulting in zero Nernst conductivity. We discuss two possible experimental setups, representing open and closed thermoelectric circuits.

  • 18. Frank, Rupert L.
    et al.
    Hainzl, Christian
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    The BCS critical temperature in a weak homogeneous magnetic field2019Inngår i: Journal of Spectral Theory, ISSN 1664-039X, E-ISSN 1664-0403Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that, within a linear approximation of BCS theory, a weak homogeneous magnetic field lowers the critical temperature by an explicit constant times the field strength, up to higher order terms. This provides a rigorous derivation and generalization of results obtained in the physics literature fromWHH theory of the upper critical magnetic field. A new ingredient in our proof is a rigorous phase approximation to control the effects of the magnetic field.

  • 19. Fransson, J.
    et al.
    Thonig, D.
    Bessarab, P. F.
    Bhattacharjee, S.
    Hellsvik, Johan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Nordström, L.
    Microscopic theory for coupled atomistic magnetization and lattice dynamics2017Inngår i: Physical Review Materials, ISSN 2475-9953, Vol. 1, nr 7, artikkel-id 074404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A coupled atomistic spin and lattice dynamics approach is developed which merges the dynamics of these two degrees of freedom into a single set of coupled equations of motion. The underlying microscopic model comprises local exchange interactions between the electron spin and magnetic moment and the local couplings between the electronic charge and lattice displacements. An effective action for the spin and lattice variables is constructed in which the interactions among the spin and lattice components are determined by the underlying electronic structure. In this way, expressions are obtained for the electronically mediated couplings between the spin and lattice degrees of freedom, besides the well known interatomic force constants and spin-spin interactions. These former susceptibilities provide an atomistic ab initio description for the coupled spin and lattice dynamics. It is important to notice that this theory is strictly bilinear in the spin and lattice variables and provides a minimal model for the coupled dynamics of these subsystems and that the two subsystems are treated on the same footing. Questions concerning time-reversal and inversion symmetry are rigorously addressed and it is shown how these aspects are absorbed in the tensor structure of the interaction fields. By means of these results regarding the spin-lattice coupling, simple explanations of ionic dimerization in double-antiferromagnetic materials, as well as charge density waves induced by a nonuniform spin structure, are given. In the final parts, coupled equations of motion for the combined spin and lattice dynamics are constructed, which subsequently can be reduced to a form which is analogous to the Landau-Lifshitz-Gilbert equations for spin dynamics and a damped driven mechanical oscillator for the ionic motion. It is important to notice, however, that these equations comprise contributions that couple these descriptions into one unified formulation. Finally, Kubo-like expressions for the discussed exchanges in terms of integrals over the electronic structure and, moreover, analogous expressions for the damping within and between the subsystems are provided. The proposed formalism and types of couplings enable a step forward in the microscopic first principles modeling of coupled spin and lattice quantities in a consistent format.

  • 20.
    Fu, Jie
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. Ningbo Univ, Peoples R China; Dalian Univ Technol, Peoples R China.
    Zhao, Jijun
    Plyasunov, Andrey V.
    Belonoshko, Anatoly
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Ab initio molecular dynamics study of fluid H2O-CO2 mixture in broad pressure-temperature range2017Inngår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 7, nr 11, artikkel-id 115217Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Properties of H2O and CO2 fluid and their mixtures under extreme pressures and temperatures are poorly known yet critically important in a number of applications. Several hundreds of first-principles molecular dynamics (FPMD) runs have been performed to obtain the pressure-volume-temperature (P-V-T) data on supercritical H2O, CO2, and H2O-CO2 mixtures. The pressure-temperature (P-T) range are from 0.5 GPa to 104 GPa (48.5 GPa for CO2) and from 600 K to 4000 K. Based on these data, we evaluate several existing equations of state (EOS) for the fluid H2O, CO2, and H2O-CO2 mixture. The results show that the EOS for H2O from Belonoshko et al. [Geochim. Cosmochim. Acta 55, 381-387; Geochim. Cosmochim. Acta 55, 3191-3208; Geochim. Cosmochim. Acta 56, 3611-3626; Comput. Geosci. 18, 1267-1269] not only can be used in the studied P-T range but also is accurate enough to be used for prediction of P-V-T data. In addition, IAPWS-95 EOS for H2O shows excellent extrapolation behavior beyond 1.0 GPa and 1273 K. However, for the case of CO2, none of the existing EOS produces data in agreement with the FPMD results. We created new EOS for CO2. The precision of the new EOS is tested by comparison to the calculated P-V-T data, fugacity coefficient of the CO2 fluid derived from high P-T experimental data as well as to the (very scarce) experimental volumetric data in the high P-T range. On the basis of our FPMD data we created a new EOS for H2O-CO2 mixture. The new EOS for the mixture is in reasonable agreement with experimental data.

  • 21. Giblin, S. R.
    et al.
    Twengström, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    et al.,
    Pauling entropy, metastability and equilibrium in Dy2Ti2O7spin iceManuskript (preprint) (Annet vitenskapelig)
  • 22. Grinenko, Vadim
    et al.
    Weston, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Kihou, Kunihiro
    Sarkar, Rajib
    Dengre, Shanu
    Huhne, Ruben
    Nielsch, Kornelius
    Lee, Chul-Ho
    Babaev, Egor
    Klauss, Hans-Henning
    Bosonic Z2 metal: Spontaneous breaking of time-reversal symmetry due to Cooper pairing in the resistive state of Ba1−xKxFe2As2Manuskript (preprint) (Annet vitenskapelig)
  • 23.
    Hauschild, Johannes
    et al.
    Tech Univ Munich, Dept Phys, T42,James Franck Str 1, D-85748 Garching, Germany..
    Leviatan, Eyal
    Weizmann Inst Sci, Dept Condensed Matter Phys, IL-7610001 Rehovot, Israel..
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Altman, Ehud
    Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA..
    Zaletel, Michael P.
    Princeton Univ, Dept Phys, Princeton, NJ 08540 USA..
    Pollmann, Frank
    Tech Univ Munich, Dept Phys, T42,James Franck Str 1, D-85748 Garching, Germany..
    Finding purifications with minimal entanglement2018Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, nr 23, artikkel-id 235163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purification is a tool that allows to represent mixed quantum states as pure states on enlarged Hilbert spaces. A purification of a given state is not unique and its entanglement strongly depends on the particular choice made. Moreover, in one-dimensional systems, the amount of entanglement is linked to how efficiently the purified state can be represented using matrix-product states (MPS). We introduce an MPS based method that allows to find the minimally entangled representation by iteratively minimizing the second Renyi entropy. First, we consider the thermofield double purification and show that its entanglement can be strongly reduced especially at low temperatures. Second, we show that a slowdown of the entanglement growth following a quench of an infinite temperature state is possible.

  • 24.
    Hellsvik, Johan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Thonig, Danny
    Modin, Klas
    Iusan, Diana
    Bergman, Anders
    Eriksson, Olle
    Bergqvist, Lars
    Delin, Anna
    General method for atomistic spin-lattice dynamics with first-principles accuracy2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 10, artikkel-id 104302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a computationally efficient and general first-principles based method for spin-lattice simulations for solids and clusters. The method is based on a coupling of atomistic spin dynamics and molecular dynamics simulations, expressed through a spin-lattice Hamiltonian, where the bilinear magnetic term is expanded up to second order in displacement. The effect of first-order spin-lattice coupling on the magnon and phonon dispersion in bcc Fe is reported as an example, and we observe good agreement with previous simulations. We also illustrate the coupled spin-lattice dynamics method on a more conceptual level, by exploring dissipation-free spin and lattice motion of small magnetic clusters (a dimer, trimer, and tetramer). The method discussed here opens the door for a quantitative description and understanding of the microscopic origin of many fundamental phenomena of contemporary interest, such as ultrafast demagnetization, magnetocalorics, and spincaloritronics.

  • 25.
    Herviou, Loic
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori. KTH Royal Inst Technol, Dept Phys, S-10691 Stockholm, Sweden..
    Regnault, Nicolas
    Univ Paris Diderot, Sorbonne Paris Cite, Sorbonne Univ, ENS,Univ PSL,CNRS,Lab Phys Ecole Normale Super, Paris, France..
    Defining a bulk-edge correspondence for non-Hermitian Hamiltonians via singular-value decomposition2019Inngår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 99, nr 5, artikkel-id 052118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We address the breakdown of the bulk-boundary correspondence observed in non-Hermitian systems, where open and periodic systems can have distinct phase diagrams. The correspondence can be completely restored by considering the Hamiltonian's singular-value decomposition instead of its eigendecomposition. This leads to a natural topological description in terms of a flattened singular decomposition. This description is equivalent to the usual approach for Hermitian systems and coincides with a recent proposal for the classification of non-Hermitian systems. We generalize the notion of the entanglement spectrum to non-Hermitian systems, and show that the edge physics is indeed completely captured by the periodic bulk Hamiltonian. We exemplify our approach by considering the chiral non-Hermitian Su-Schrieffer-Heger and Chern insulator models. Our work advocates a different perspective on topological non-Hermitian Hamiltonians, paving the way to a better understanding of their entanglement structure.

  • 26.
    Herviou, Loic
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Bera, Soumya
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Multiscale entanglement clusters at the many-body localization phase transition2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 13, artikkel-id 134205Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We numerically study the formation of entanglement clusters across the many-body localization transition. We observe a crossover from strong many-body entanglement in the ergodic phase to weak local correlations in the localized phase, with continuous clusters throughout the phase diagram. Critical states close to the transition have a structure compatible with fractal or multiscale-entangled states, characterized by entanglement at multiple levels: small strongly entangled clusters are weakly entangled together to form larger clusters. The critical point therefore features subthermal entanglement and a power-law distributed cluster size. Upon entering the localized phase, the power-law distribution seems to persist with a varying power that crosses over into a stretched exponent before eventually becoming exponential deep in the localized phase. These results are in agreement with some of the recently proposed phenomenological renormalization-group schemes characterizing the many-body localized critical point, and serve to constrain other such schemes.

  • 27.
    Herviou, Loic
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Le Hur, Karyn
    Univ Paris Saclay, Ctr Phys Theor, CNRS, Ecole Polytech, F-91128 Palaiseau, France..
    Mora, Christophe
    Univ Paris Diderot, Univ Pierre & Marie Curie, Ecole Normale Super,PSL Res Univ, Lab Pierre Aigrain,Sorbonne Paris Cite,Sorbonne U, 24 Rue Lhomond, F-75231 Paris 05, France..
    Bipartite fluctuations and topology of Dirac and Weyl systems2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 7, artikkel-id 075133Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bipartite fluctuations can provide interesting information about entanglement properties and correlations in many-body quantum systems. We address such fluctuations in relation with the topology of Dirac and Weyl quantum systems, in situations where the relevant particle number is not conserved, leading to additional volume laws scaling with the quantum Fisher information. In the case of the p + ip superconductor, we build a relation between charge fluctuations and the associated winding numbers of Dirac cones in the low-energy sector. Topological aspects of the Hamiltonian in the vicinity of these points induce long-range entanglement in real space. We specifically extract analytical expressions for the corner contributions to bipartite fluctuations. We highlight their differences and similarities with the corner functions of the entanglement entropy which characterize the underlying conformal field theory. We provide a detailed analysis of such fluctuation properties, including the role of gap anisotropy, and discuss higher-dimensional Weyl analogs.

  • 28.
    Javanmard, Younes
    et al.
    Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany..
    Trapin, Daniele
    Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany..
    Bera, Soumya
    Indian Inst Technol, Dept Phys, Bombay 400076, Maharashtra, India..
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Heyl, Markus
    Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany..
    Sharp entanglement thresholds in the logarithmic negativity of disjoint blocks in the transverse-field Ising chain2018Inngår i: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 20, artikkel-id 083032Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Entanglement has developed into an essential concept for the characterization of phases and phase transitions in ground states of quantum many-body systems. In this work we use the logarithmic negativity to study the spatial entanglement structure in the transverse-field Ising chain both in the ground state and at nonzero temperatures. Specifically, we investigate the entanglement between two disjoint blocks as a function of their separation, which can be viewed as the entanglement analog of a spatial correlation function. We find sharp entanglement thresholds at a critical distance beyond which the logarithmic negativity vanishes exactly and thus the two blocks become unentangled, which holds even in the presence of long-ranged quantum correlations, i.e., at the system's quantum critical point. Using time-evolving block decimation, we explore this feature as a function of temperature and size of the two blocks and present a simple model to describe our numerical observations.

  • 29.
    Kaladzhyan, Vardan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Bardarson, Jens H.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Quantized Fermi arc mediated transport in Weyl semimetal nanowires2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 100, nr 8, artikkel-id 085424Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study longitudinal transport in Weyl semimetal nanowires, both in the absence and in the presence of a magnetic flux threading the nanowires. We identify two qualitatively different regimes of transport with respect to the chemical potential in the nanowires. In the "surface regime," for low doping, most of the conductance occurs through the Fermi arc surface states, and it rises in steps of one quantum of conductance as a function of the chemical potential; furthermore, with varying flux the conductance changes in steps of one quantum of conductance with characteristic Fabry-Perot interference oscillations. In the "bulk-surface regime," for highly doped samples, the dominant contribution to the conductance is quadratic in the chemical potential, and mostly conditioned by the bulk states; the flux dependence shows clearly that both the surface and the bulk states contribute. The two aforementioned regimes prove that the contribution of Fermi arc surface states is salient and, therefore, crucial for understanding transport properties of finite-size Weyl semimetal systems. Last but not least, we demonstrate that both regimes are robust to disorder.

  • 30.
    Kevrekidis, P. G.
    et al.
    Univ Massachusetts, Dept Math & Stat, Amherst, MA 01003 USA..
    Wang, Wenlong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Theocharis, G.
    Univ Maine, UMR CNRS 6613, Lab Acoust, Ave Olivier Messiaen, F-72000 Le Mans, France..
    Frantzeskakis, D. J.
    Univ Athens, Dept Phys, Athens 15784, Greece..
    Carretero-Gonzalez, R.
    San Diego State Univ, Nonlinear Dynam Syst Grp, Computat Sci Res Ctr, San Diego, CA 92182 USA.;San Diego State Univ, Dept Math & Stat, San Diego, CA 92182 USA..
    Anderson, B. P.
    Univ Arizona, Coll Opt Sci, Tucson, AZ 85721 USA..
    Dynamics of interacting dark soliton stripes2019Inngår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 100, nr 3, artikkel-id 033607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work we examine the statics and dynamics of multiple parallel dark soliton stripes in a two-dimensional Bose-Einstein condensate. Our principal goal is to study the effect of the interaction between the stripes on the transverse instability of the individual stripes. The cases of two-, three-, and four-stripe states are studied in detail. We use a recently developed adiabatic invariant formulation to derive a quasianalytical prediction for the stripe equilibrium position and for the Bogoliubov-de Gennes spectrum of excitations of stationary stripes. We subsequently test our predictions against numerical simulations of the full two-dimensional Gross-Pitaevskii equation. We find that the number of unstable eigenmodes increases as the number of stripes increases due to (unstable) relative motions between the stripes. Their corresponding growth rates do not significantly change, although for large chemical potentials, the larger the stripe number, the larger the maximal instability growth rate. The instability induced dynamics of multiple stripe states and their decay into vortices are also investigated.

  • 31.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    (3+1)-Dimensional Schwinger Terms and Non-commutative Geometry1994Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 338, s. 241-248Artikkel i tidsskrift (Fagfellevurdert)
  • 32.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    A superversion of quasifree second quantization. I. Charged particles1992Inngår i: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 3, nr 3, s. 1032-1046Artikkel i tidsskrift (Fagfellevurdert)
  • 33.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Bc2(T) of anisotropic systems: some explicit results1990Inngår i: Physica B: Physics of Condensed Matter, Vol. 65, s. 1061-1062Artikkel i tidsskrift (Fagfellevurdert)
  • 34.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Cocycles for Boson and Fermion Bogoliubov Transformations1994Inngår i: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 35, s. 96-112Artikkel i tidsskrift (Fagfellevurdert)
  • 35.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Consistent axial-like gauge fixing on hypertori1994Inngår i: Modern Physics Letters A, ISSN 0217-7323, E-ISSN 1793-6632, Vol. 9, s. 2913-2926Artikkel i tidsskrift (Fagfellevurdert)
  • 36.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Descent equations of Yang-Mills anomalies in noncommutative geometry1997Inngår i: Journal of Geometry and Physics, ISSN 0393-0440, E-ISSN 1879-1662, s. 259-279Artikkel i tidsskrift (Fagfellevurdert)
  • 37.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Elementary Derivation of the Chiral Anomaly1996Inngår i: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 6, s. 45-54Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Fermion Current Algebras and Schwinger Terms in 3+1 Dimensions1994Inngår i: Communications in Mathematical Physics, ISSN 0010-3616, E-ISSN 1432-0916, Vol. 162, s. 1-32Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Fermi-surface harmonics in the theory of the upper critical field1992Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 46, nr 14, s. 9104-Artikkel i tidsskrift (Fagfellevurdert)
  • 40.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Finding and solving Calogero-Moser type systems using Yang-Mills gauge theories1999Inngår i: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 563, s. 506-532Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Gauge Theories on a Cylinder1992Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 296, s. 117-120Artikkel i tidsskrift (Fagfellevurdert)
  • 42.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Gribov ambiguity and non-trivial vacuum structure of gauge theories on a cylinder1993Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 303, s. 303-307Artikkel i tidsskrift (Fagfellevurdert)
  • 43.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Loop groups, anyons and the Calogero-Sutherland model1999Inngår i: Communications in Mathematical Physics, ISSN 0010-3616, E-ISSN 1432-0916, Vol. 201, s. 1-34Artikkel i tidsskrift (Fagfellevurdert)
  • 44.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Mean field approach to antiferromagnetic domains in the doped Hubbard model1997Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, s. 9439-9451Artikkel i tidsskrift (Fagfellevurdert)
  • 45.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Non-commutative Integration Calculus1995Inngår i: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 36, s. 3822-3835Artikkel i tidsskrift (Fagfellevurdert)
  • 46.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Novel integrable spin-particle models from gauge theories on a cylinder1998Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 429, s. 336-342Artikkel i tidsskrift (Fagfellevurdert)
  • 47.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    On current superalgebras and super-Schwinger terms1991Inngår i: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, nr 1, s. 69-76Artikkel i tidsskrift (Fagfellevurdert)
  • 48.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    On the upper critical field of anisotropic superconductors1991Inngår i: Physica. C, Superconductivity, ISSN 0921-4534, E-ISSN 1873-2143, Vol. 73, s. 347-356Artikkel i tidsskrift (Fagfellevurdert)
  • 49.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    QCD(1+1) with massless quarks and gauge covariant Sugawara construction1994Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 341, s. 195-204Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Quantum Gauge Theories and Noncommutative Geometry1996Inngår i: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 27, s. 2477-2496Artikkel i tidsskrift (Fagfellevurdert)
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