Endre søk
Begrens søket
1234 151 - 189 of 189
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 151. Sehat, A.
    et al.
    Soderholm, J.
    Björk, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Espinoza, P.
    Klimov, A. B.
    Sanchez-Soto, L. L.
    Quantum polarization properties of two-mode energy eigenstates2005Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 71, nr 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that any pure, two-mode, N-photon state with N odd or equal to two can be transformed into an orthogonal state using only linear optics. According to a recently suggested definition of polarization degree, this implies that all such states are fully polarized. This is also found to be true for any pure, two-mode, energy eigenstate belonging to a two-dimensional SU(2) orbit. Complete two- and three-photon bases whose basis states are related by only phase shifts or geometrical rotations are also derived.

  • 152. Setala, Tero
    et al.
    Shevchenko, Andriy
    Kaivola, Matti
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Polarization time and length for random optical beams2008Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 78, nr 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the dynamics of the instantaneous polarization state of stationary, partially polarized random electromagnetic beamlike fields. An intensity-normalized correlation function of the instantaneous Poincare vector is introduced for the characterization of the time evolution of the polarization state. This polarization correlation function enables us to define a polarization time and a polarization length over which the polarization state remains substantially unchanged. In the case of Gaussian statistics, the polarization correlation function is shown to assume a simple form in terms of the parameters employed to characterize partial coherence and partial polarization of electromagnetic fields. The formalism is demonstrated for a partially polarized, temporally Gaussian-correlated beam, and black-body radiation. The results are expected to find a range of applications in investigations of phenomena where polarization fluctuations of light play an important role.

  • 153. Setala, Tero
    et al.
    Shirai, Tomohiro
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Fractional Fourier transform in temporal ghost imaging with classical light2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 4, s. 043813-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate temporal, second-order classical ghost imaging with long, incoherent, scalar plane-wave pulses. We prove that in rather general conditions, the intensity correlation function at the output of the setup is given by the fractional Fourier transform of the temporal object. In special cases, the correlation function is shown to reduce to the ordinary Fourier transform and the temporal image of the object. Effects influencing the visibility and the resolution are considered. This work extends certain known results on spatial ghost imaging into the time domain and could find applications in temporal tomography of pulses.

  • 154. Setälä, Tero
    et al.
    Hakkarainen, Timo
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Hoenders, Bernhard J.
    Object-dependent cloaking in the first-order Born approximation2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 1, s. 013814-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We consider the cloaking of a slab object in scalar wave theory within the first-order Born approximation. We show that in the forward direction cloaking is achieved for any transversally invariant, positively refracting, and absorbing object by using a lossy, negative-index metamaterial cloak. Cloaking is perfect and occurs for incident fields having any spatial structure and bandwidth. In the backward direction cloaking is found to be possible for self-imaging fields. In both cases the refractive-index distribution and dispersive properties of the cloak slab resemble those of the object slab. The method of object-dependent cloaking with weak scatterers may find useful applications.

  • 155.
    Shabbir, Saroosh
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Swillo, Marcin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Björk, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Synthesis of arbitrary, two-mode, high-visibility N-photon interference patterns2013Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, nr 5, s. 053821-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using coherent states, linear optics, and N-photon detection we demonstrate the synthesis of arbitrary interference patterns and establish that neither the shape nor the visibility of N-photon interference patterns can be used as a quantum signature in general. Specific examples include saw-curve and rectangle-curve interference patterns and phase super-resolution with period shortening of up to 60 times compared to ordinary interference. The former two have visibility close to 100% and the latter has visibility in excess of 57%.

  • 156.
    Shen, Jian Qi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang Univ, Peoples R China.
    Electromagnetically-induced-transparency plasmonics: Quantum-interference-assisted tunable surface-plasmon-polariton resonance and excitation2014Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 90, nr 2, s. 023814-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimentally feasible configuration of a prism coupler with an electromagnetically-induced-transparency (EIT) medium layer, e.g., a semiconductor-quantum-dot (SQD) medium, deposited upon its prism base is suggested for generating tunable surface-plasmon-polariton resonance. Such surface-plasmon-polariton resonance and optical excitation of a surface plasmon wave can be manipulated by switchable quantum interference among SQD multilevel transitions driven by two external control fields. When an incident probe field is coupled into a surface plasmon wave excitation mode, the surface-plasmon-polariton (SPP) resonance at the interface between the SQD medium layer and the substrate will arise, and the quantum-coherently controllable reflection spectrum of the probe field on the prism base can be achieved. In this process, destructive and constructive quantum interference (determined by the intensity ratio of the two external control fields) in the SQD multilevel system plays a key role for achieving the tunable reflection spectrum. The EIT-based surface-plasmon-polariton resonance presented here will have three characteristics (some of them would be attractive): (i) switchable quantum interference exhibited by surface plasmon wave excitation, (ii) quantum-coherently controllable surface plasmon polaritons by external optical fields, (iii) surface wave sensitive to dispersion of the SQD quantum coherent medium. Such an effect of controllable optical response based on the quantum-interference switchable surface-plasmon-polariton resonance in the EIT-prism coupler may find some potential applications in design of new photonic and quantum optical devices.

  • 157.
    Shen, Jianqi
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Centra, Alfvénlaboratoriet.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Centra, Alfvénlaboratoriet.
    Dimension-sensitive optical responses of electromagnetically induced transparency vapor in a waveguide2006Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 74, nr 063831Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A three-level EIT (electromagnetically induced transparency) vapor is used to manipulate the transparency and absorption properties of the probe light in a waveguide. The most remarkable feature of the present scheme is such that the optical responses resulting from both electromagnetically induced transparency and large spontaneous emission enhancement are very sensitive to the frequency detunings of the probe light as well as to the small changes of the waveguide dimension. The potential applications of the dimension- and dispersion-sensitive EIT responses are discussed, and the sensitivity limits of some waveguide-based sensors, including electric absorption modulator, optical switch, wavelength sensor, and sensitive magnetometer, are analyzed.

  • 158. Shirai, Tomohiro
    et al.
    Setala, Tero
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ghost imaging of phase objects with classical incoherent light2011Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 84, nr 4, s. 041801-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe an optical setup for performing spatial Fourier filtering in ghost imaging with classical incoherent light. This is achieved by a modification of the conventional geometry for lensless ghost imaging. It is shown on the basis of classical coherence theory that with this technique one can realize what we call phase-contrast ghost imaging to visualize pure phase objects.

  • 159. Simon, M.
    et al.
    Journel, L.
    Guillemin, R.
    Stolte, W.C.
    Minkov, Ivaylo
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Gelmukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Salek, Pawel
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Carniato, S.
    Taïeb, R.
    Hudson, A.C.
    Lindle, D.W.
    Femtosecond nuclear motion of HCl probed by resonant x-ray Raman scattering in the Cl 1s region2006Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 73, nr 2, s. 020706(R)-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Femtosecond dynamics are observed by resonant x-ray Raman scattering (RXS) after excitation along the dissociative Cl 1s -> 6 sigma(*) resonance of gas-phase HCl. The short core-hole lifetime results in a complete breakdown of the common nondispersive behavior of soft-x-ray transitions between parallel potentials. We evidence a general phenomenon of RXS in the hard-x-ray region: a complete quenching of vibrational broadening. This opens up a unique opportunity for superhigh resolution x-ray spectroscopy beyond vibrational and lifetime limitations.

  • 160. Soderholm, J.
    et al.
    Björk, Gunnar
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Hessmo, B.
    Inoue, S.
    Quantum limits on phase-shift detection using multimode interferometers2003Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 67, nr 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fundamental phase-shift detection properties of optical multimode interferometers are analyzed. Limits on perfectly distinguishable phase shifts are derived for general quantum states of a given average energy. These bounds are found to be independent of the number of interfering modes, and are consistent with the Heisenberg limit. A short discussion on the concept of well-defined relative phase is also included.

  • 161. Sorensen, S. L.
    et al.
    Kitajima, M.
    Tanaka, T.
    Hoshino, M.
    Tanaka, H.
    Tamenori, Y.
    Sankari, R.
    Piancastelli, M. N.
    Ueda, K.
    Velkov, Yasen
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Minkov, Ivaylo
    KTH, Skolan för bioteknologi (BIO).
    Carravetta, V.
    Gelmukhanov, Faris
    KTH, Skolan för bioteknologi (BIO).
    Electronic Doppler effect in resonant Auger decay of CO molecules upon excitation near a shake-up Pi resonance2007Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 76, nr 062704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wepresent an experimental observation of the electronic Doppler effect inresonant Auger spectra upon core excitation slightly above the carbonK edge of the CO molecule. Thus the electronic Dopplereffect has been identified in above-threshold excitation, and in atransition of symmetry. Ab initio calculations of the potentialenergy curves of the relevant states of CO and thewave packet technique have been employed to provide a theoreticalbackground to the experimental studies. The weak feature around 299.4  eVin the photoabsorption spectrum, whose decay has been investigated bythe present experiment, is assigned to double (core-valence) excitations toC 1s shake-up states |1s1−1*2 with a strong dissociative character,and the Doppler splitting of the atomic peak has beenreproduced by the simulation.

  • 162.
    Stenrup, Michael
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Larson, Åsa
    Department of Physics, Stockholm University.
    Elander, Nils
    Department of Physics, Stockholm University.
    Mutual neutralization in low-energy H++H- collisions: A quantum ab initio study2009Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 79, nr 1, s. 012713-1-012713-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mutual neutralization of H+ and H- at low collision energies is studied by means of a molecular close-coupling approach. All degrees of freedom are treated at the full quantum level also taking into account the identity of the nuclei. The relevant (1)Sigma(+)(g) and (1)Sigma(+)(u) electronic states as well as the associated nonadiabatic radial couplings are calculated for internuclear distances between 0.5 and 50a(0). Following a transformation into a strictly diabatic basis, these quantities enter into a set of coupled equations for the motion of the nuclei. Numerical solution of these equations allows the cross sections for neutralization into the H(1)+H(n), n=1,2,3 final states to be calculated. In the present paper, results are reported for the collision energy region 0.001-100 eV, with special emphasis on the important energy region below 10 eV. The low temperature rate coefficient is obtained from a parametrization of the calculated cross section and is estimated to be valid over the range 10-10 000 K.

  • 163.
    Strömqvist, Gustav
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Montes, C.
    Coherent phase-modulation transfer in counterpropagating parametric down-conversion2011Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 84, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Distributed positive feedback established by a counterpropagating three-wave mixing process in a submicrometer structured second-order nonlinear medium leads to mirrorless parametric oscillation with unusual spectral properties. In this work, we demonstrate experimentally and theoretically that the phase modulation of the pump is coherently transferred to the co-propagating parametric wave, while the counterpropagating wave retains a narrow bandwidth and high coherence. The main mechanisms responsible for these properties are the maximized convective separation between the counterpropagating waves and the associated phase-locking between the pump and the co-propagating parametric wave. This suggests that mirrorless optical parametric oscillators can be pumped with incoherent light and still generate highly coherent backward-propagating radiation.

  • 164.
    Sun, Yu-Ping
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Liu, Ji-Cai
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Wang, Chuan-Kui
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Gel'mukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Propagation of a strong x-ray pulse: Pulse compression, stimulated Raman scattering, amplified spontaneous emission, lasing without inversion, and four-wave mixing2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 81, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the compression of strong x-ray pulses from x-ray free-electron lasers (XFELs) propagating through the resonant medium of atomic argon. The simulations are based on the three-level model with the frequency of the incident x-ray pulse tuned in the 2p(3/2)-4s resonance. The pulse propagation is accompanied by the self-seeded stimulated resonant Raman scattering (SRRS). The SRRS starts from two channels of amplified spontaneous emission (ASE), 4s-2p(3/2) and 3s-2p(3/2), which form the extensive ringing pattern and widen the power spectrum. The produced seed field triggers the Stokes ASE channel 3s-2p(3/2). The population inversion is quenched for longer propagation distances where the ASE is followed by the lasing without inversion (LWI), which amplifies the Stokes component. Both ASE and LWI reshape the input pulse: The compressed front part of the pulse (up to 100 as) is followed by the long tail of the ringing and beating between the pump and Stokes frequencies. The pump pulse also generates weaker Stokes and anti-Stokes fields caused by four-wave mixing. These four spectral bands have fine structures caused by the dynamical Stark effect. A slowdown of the XFEL pulse up to 78% of the speed of light in vacuum is found because of a large nonlinear refractive index.

  • 165.
    Sun, Yu-Ping
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Rinkevicius, Zilvinas
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Wang, Chuan-Kui
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Carniato, Stephane
    Simon, Marc
    Taieb, Richard
    Gel'mukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Two-photon-induced x-ray emission in neon atoms2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 4, s. 043430-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the resonant x-ray emission from a neon atom induced by the two-photon population of a double-core-hole excited state. Two qualitatively different schemes of this process are studied: The first one involves an off-resonant intermediate single-core-hole state; the second scheme passes through a resonant core-ionized intermediate state. The numerical simulations of the resonant x-ray emission performed for different peak intensities and pulse durations show significant population of the double-core-hole final states. Therefore, rather strong two-photon absorption-induced x-ray emission is predicted for both studied schemes. Thus, high counting rates in experimental measurements are expected.

  • 166.
    Sun, Yuping
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Wang, Chuankui
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Gel'mukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Rotational Doppler effect in x-ray photoionization2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 5, s. 052506-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The energy of the photoelectron experiences a red or blue Doppler shift when the molecule recedes from the detector or approaches him. This results in a broadening of the photoelectron line due to the translational thermal motion. However, the molecules also have rotational degrees of freedom and we show that the translational Doppler effect has its rotational counterpart. This rotational Doppler effect leads to an additional broadening of the spectral line of the same magnitude as the Doppler broadening caused by translational thermal motion. The rotational Doppler broadening as well as the rotational recoil broadening is sensitive to the molecular orbital from which the photoelectron is ejected. This broadening should be taken into account in analysis of x-ray photoemission spectra of super-high resolution and it can be directly observed using x-ray pump-probe spectroscopy.

  • 167. Tashenov, S.
    et al.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Barday, R.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Enders, J.
    Khaplanov, Anton
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Fritzsche, Yu
    Schässburger, Kai-Uwe
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Surzhykov, A.
    Yerokhin, V. A.
    Jakubassa-Amundsen, D.
    Bremsstrahlung polarization correlations and their application for polarimetry of electron beams2013Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, nr 2, s. 022707-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Linear polarization of hard x rays emitted in the process of atomic-field electron bremsstrahlung has been measured with a polarized electron beam. The correlation between the initial orientation of the electron spin and the angle of photon polarization has been systematically studied by means of Compton and Rayleigh polarimetry techniques applied to a segmented germanium detector. The results are in good agreement with those of fully relativistic calculations. The observed correlations are also explained classically and in a unique way manifest that due to the spin-orbit interaction the electron scattering trajectory is not confined to a single scattering plane. The developed photon polarimetry technique with a passive scatterer is very efficient and accurate and thus allows for additional applications. Bremsstrahlung polarization correlations lead to an alternative method of polarimetry of electron beams. Such a method is sensitive to all three components of the electron spin. It can be applied in a broad range of the electron beam energies from approximate to 100 keV up to a few tens of MeV. The results of a measurement at 100 keV are shown. The optimum scheme for electron polarimetry is analyzed and the relevant theoretical predictions are presented.

  • 168.
    Thiyam, Priyadarshini
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Parashar, Prachi
    Shajesh, K. V.
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM). University of Oslo, Norway.
    Schaden, Martin
    Brevik, Iver
    Parsons, Drew F.
    Milton, Kimball A.
    Malyi, Oleksandr I.
    Bostrom, Mathias
    Anisotropic contribution to the van der Waals and the Casimir-Polder energies for CO2 and CH4 molecules near surfaces and thin films2015Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 92, nr 5, artikkel-id 052704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to understand why carbon dioxide (CO2) and methane (CH4) molecules interact differently with surfaces, we investigate the Casimir-Polder energy of a linearly polarizable CO2 molecule and an isotropically polarizable CH4 molecule in front of an atomically thin gold film and an amorphous silica slab. We quantitatively analyze how the anisotropy in the polarizability of the molecule influences the van der Waals contribution to the binding energy of the molecule.

  • 169.
    Thiyam, Priyadarshini
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM).
    Brevik, I.
    Sernelius, Bo E.
    Boström, Mathias
    Nonperturbative theory for the dispersion self-energy of atoms2014Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 90, nr 5, s. 054502-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We go beyond the approximate series expansions used in the dispersion theory of finite-size atoms. We demonstrate that a correct, and nonperturbative, theory dramatically alters the dispersion self-energies of atoms. The nonperturbed theory gives as much as 100% corrections compared to the traditional series-expanded theory for the smaller noble gas atoms.

  • 170. Thomas, T.D.
    et al.
    Kukk, E.
    Fukuzawa, H.
    Ueda, K.
    Puettner, R.
    Tamenori, Y.
    Asahina, T.
    Kuze, N.
    Kato, H.
    Hoshino, M.
    Tanaka, H.
    Meyer, M.
    Plenge, J.
    Wirsing, A.
    Serdaroglu, E.
    Flesch, R.
    Ruehl, E.
    Gavrilyuk, S.
    Gelmukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Lindblad, A.
    Saethre, L. J.
    Photoelectron-recoil-induced rotational excitation of the B 2 state in N2+2009Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 79, nr 022506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the photoelectron spectrum of N-2 the apparent ionization energy to form the B (2)Sigma(+)(u) state increases linearly with the photon energy. Rotationally resolved measurements of the fluorescent decay of this state show a linear increase of rotational heating with increasing photon energy. These results are in quantitative agreement with the prediction of the theory of recoil-induced rotational excitation, indicating that the rotational heating that has been observed previously arises primarily from such recoil-induced excitation. Together with other results that have been reported they show that recoil-induced internal excitation is significant in many situations, including near threshold.

  • 171. Tian, Shan Xi
    et al.
    Luo, Yi
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. University of Science and Technology of China, China .
    Reply to "Comment on 'Coherent interference in the resonant dissociative electron attachment to carbon monoxide'"2015Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 91, nr 5, artikkel-id 056702Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We respond to Nag and Nandi's Comment on our paper [Phys. Rev. A 88, 012708 ( 2013)], in which the arguments arise from the data analyses of the angular distributions of O- produced in the dissociative electron attachments to CO at 10.5 or 10.6 eV although the same technique, anion-velocity time-sliced map imaging, was used. The forward distribution in the O- image observed by Nag and Nandi arises from the low momentum resolution and distortion in their ion velocity imaging measurements. These artifacts are due to their arbitrary elongation of the ion flight tube and the uncertainty in the size control of the reaction volume.

  • 172. Tian, Shan Xi
    et al.
    Wu, Bin
    Xia, Lei
    Wang, Yong-Feng
    Li, Hong-Kai
    Zeng, Xian-Jin
    Luo, Yi
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Yang, Jinglong
    Coherent interference in the resonant dissociative electron attachment to carbon monoxide2013Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 88, nr 1, s. 012708-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dissociative electron attachment to carbon monoxide, e(-) + CO -> C + O-, at 9.5, 10.0, and 10.6 eV is investigated by using the anion velocity time-sliced map imaging technique. The completely backward scattering distributions of the fast O- fragment are observed at 10.0 and 10.6 eV. The single electron-molecule resonance model fails in interpretation to these unusual angular distributions, while a quantum interference model including two (at 10.0 eV) or three (at 10.6 eV) dissociative outgoing waves is consequently proposed and provides the satisfying results about the experimental data fittings. Moreover, coherent interference among the (2)Pi, (2)Delta, and (2)Phi resonant states of CO- at 10.6 eV could be further established, based on the fact that the sum of the phase-shift fitting values equals pi rad.

  • 173.
    Tidström, Jonas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Andersson, Mauritz
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Overtone generation in driven coherent media2009Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 79, nr 6, s. 063832-1-063832-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We observe overtone signal generation of a near-resonant bichromatic light field interacting with 85Rb on the Zeeman split F=2F=1,2,3 hyperfine transitions of the D2 line at 780 nm. A nonperturbative theoretical model for electromagnetically induced transparency is developed in order to explain this phenomenon. Assuming a  system, an explicit and convenient expression for the atomic coherence is derived from the Lindblad equation assuming a phase-damping channel. The light field state is parametrically varied through one beat note of the bichromatic field and the spatial properties are studied by numerically solving the coupled-wave equation. The polarization characteristics is analyzed on the Poincaré sphere, which together with field intensity analysis offers a simple explanation of the harmonic beating signal due to Stokes vector rotation around the Poincaré sphere and decoherence effects. The experimental data and theoretical analysis focus on the first and second harmonics, although many higher harmonics are present. A distinct and narrow minimum of the second-harmonic generation is measured on two-photon resonance.

  • 174.
    Tidström, Jonas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Andersson, L. Mauritz
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Delay bandwidth product of electromagnetically induced transparency media2007Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 75, nr 5, s. 053803-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The limitations on the delay-bandwidth product (DBP) in an electromagnetically induced transparency medium are investigated analytically by studying the susceptibility of the system, derived through Lindblad's master equation, including dephasing. The effect of inhomogeneous broadening is treated. It is shown that the DBP for a given material is fundamentally limited by the frequency-dependent absorption, while the residual absorption limits the penetration length of a pulse. Simple expression for the optimal choice of parameters to maximize the DBP are derived. Also, the length of a device is presented as a function of DBP and control-field Rabi frequency. Supporting these results, numerical calculations are carried out through the Maxwell-Bloch equations in the slowly varying envelope approximation. The results are scalable, hence they apply to the case of atoms or molecules in a gas as well as quantum dots and wells.

  • 175. Torres-Company, Victor
    et al.
    Lajunen, Hanna
    Lancis, Jesus
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Ghost interference with classical partially coherent light pulses2008Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 77, nr 4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The two-photon temporal coincidence detection amplitude obeys a pair of equations identical to those of classical partially coherent plane-wave pulses propagating in linearly dispersive media. These equations are also the same as the paraxial Wolf equations, for both the two-photon spatial probability amplitude and the cross-spectral density function. Therefore, a fourfold analogy between space and time, as well as between quantum entanglement and partial coherence, arises. In accordance to this, we predict nonlocal interference structures in a fourth-order interferometric configuration with classical partially coherent pulses under the assumption of Gaussian statistics. As an example, we present the classical temporal counterpart of the ghost diffraction phenomenon. Our work suggests that some time-domain entanglement phenomena that hitherto were considered as uniquely quantum can be mimicked by conventional partially coherent light pulses.

  • 176. Torres-Company, Victor
    et al.
    Lancis, Jesus
    Lajunen, Hanna
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Coherence revivals in two-photon frequency combs2011Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 84, nr 3, s. 033830-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe and theoretically analyze the self-imaging Talbot effect of entangled photon pairs in the time domain. Rich phenomena are observed in coherence propagation along dispersive media of mode-locked two-photon states with frequency entanglement exhibiting a comblike correlation function. Our results can be used to remotely transfer frequency standards through optical fiber networks with two-photon light, avoiding the requirement of dispersion compensation.

  • 177. Tsegaye, T.
    et al.
    Björk, Gunnar
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Atature, M.
    Sergienko, A. V.
    Saleh, B. E. A.
    Teich, M. C.
    Complementarity and quantum erasure with entangled-photon states2000Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 62, nr 3, s. art. no.-32106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A quantum-erasure experiment was performed on superposition states of two photons in either of two spatiotemporal modes. Symmetrical tapping of energy from the two-mode state creates a four-mode entangled state. A direct measurement of one photon in two of the modes reveals the path of the second one, thereby eliminating the possibility of observing interference between the two remaining modes. It is shown that a unitary rotation of one of the two-mode states erases the path information; as a consequence, the visibility of the other two-mode state can be resurrected.

  • 178.
    Tu, Guangde
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Rinkevicius, Zilvinas
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Vahtras, Olav
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Ekström, Ulf
    Department of Physics, Chemistry and Biology, Linköping University.
    Norman, Patrick
    Department of Physics, Chemistry and Biology, Linköping University.
    Carravetta, Vincenzo
    Institute of Chemical-Physical Processes, C.N.R..
    Self-interaction-corrected time-dependent density-functional-theory calculations of x-ray-absorption spectra2007Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 76, nr 2, s. 022506-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We outline an approach within time-dependent density functional theory that predicts x-ray spectra on an absolute scale. The approach rests on a recent formulation of the resonant-convergent first-order polarization propagator [P. Norman , J. Chem. Phys. 123, 194103 (2005)] and corrects for the self-interaction energy of the core orbital. This polarization propagator approach makes it possible to directly calculate the x-ray absorption cross section at a particular frequency without explicitly addressing the excited-state spectrum. The self-interaction correction for the employed density functional accounts for an energy shift of the spectrum, and fully correlated absolute-scale x-ray spectra are thereby obtained based solely on optimization of the electronic ground state. The procedure is benchmarked against experimental spectra of a set of small organic molecules at the carbon, nitrogen, and oxygen K edges.

  • 179. Urpelainen, S.
    et al.
    Calo, A.
    Partanen, L.
    Huttula, M.
    Niskanen, Johannes
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Kukk, E.
    Aksela, S.
    Aksela, H.
    Valence photoionization and the following fragmentation pathways in Sb-4 clusters2009Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 80, nr 4, s. 043201-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The valence photoelectron spectrum of Sb-4 clusters and the following fragmentation patterns have been studied using synchrotron radiation and electron-ion coincidence technique. An experimental photoelectron spectrum of the 5t(2) ionization of Sb-4 is presented. Theoretical molecular calculations, together with the existing data on the noble gas xenon, were used to describe the experimental results. The bonding properties of the molecular orbitals involved are used to qualitatively describe the dissociation process.

  • 180.
    Velkov, Yasen
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Hikosaka, Yasumasa
    Shigemasa, Eiji
    Kaneyasu, Tatsuo
    Tamenori, Yusuke
    Liu, Ji-Cai
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Gel'mukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    X-ray-absorption spectroscopy beyond the natural width measured in partial Auger yield mode2009Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 79, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report both experimental and theoretical studies on x-ray absorption measured using partial Auger yields of gas phase nitrogen, carbon monoxide, and oxygen molecules near the N 1s ->pi(*), O 1s ->pi(*), and O 1s ->pi(*) regions, respectively. The main tool of our study is a two-dimensional map in which resonant Auger yields are plotted as a function of photon and kinetic energy. The partial yields of the three molecules are analyzed in detail by extracting profiles along various directions in the map. Narrowing of the absorption resonances is observed along the direction of constant kinetic energy. It is shown that such profiles are similar to the conventional x-ray-absorption spectrum for a broad class of molecules whose potential energy surfaces of the final and core-excited states are almost parallel. However, substantial differences with the conventional x-ray-absorption profiles are observed in the general case of nonparallel surfaces due to the lifetime vibrational interference. Here, we suggest a systematic way to eliminate the lifetime vibrational interference.

  • 181. Vitos, L.
    et al.
    Johansson, Börje
    Kollar, J.
    Skriver, H. L.
    Local kinetic-energy density of the Airy gas2000Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 61, nr 5, s. art. no.-52511Artikkel i tidsskrift (Fagfellevurdert)
  • 182. Voipio, Timo
    et al.
    Setala, Tero
    Shevchenko, Andriy
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Polarization dynamics and polarization time of random three-dimensional electromagnetic fields2010Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 6, s. 063807-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the polarization dynamics of random, stationary three-dimensional (3D) electromagnetic fields. For analyzing the time evolution of the instantaneous polarization state, two intensity-normalized polarization autocorrelation functions are introduced, one based on a geometric approach with the Poincare vectors and the other on energy considerations with the Jones vectors. Both approaches lead to the same conclusions on the rate and strength of the polarization dynamics and enable the definition of a polarization time over which the state of polarization remains essentially unchanged. For fields obeying Gaussian statistics, the two correlation functions are shown to be expressible in terms of quantities characterizing partial 3D polarization and electromagnetic coherence. The 3D degree of polarization is found to have the same meaning in the 3D polarization dynamics as the usual two-dimensional (2D) degree of polarization does with planar fields. The formalism is demonstrated with several examples, and it is expected to be useful in applications dealing with polarization fluctuations of 3D light.

  • 183. Wang, Qin
    et al.
    Karlsson, Anders
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Performance enhancement of a decoy-state quantum key distribution using a conditionally prepared down-conversion source in the Poisson distribution2007Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 76, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the behavior of decoy-state quantum key distribution systems using a conditionally prepared down-conversion source, analyzing such a source running in a mode of operation with either a thermal photon number distribution or a Poisson photon number distribution. By comparing both modes of operations to the three-intensity proposal of Wang , to the one-intensity proposal of Adachi , and to the currently demonstrated faint-laser pulse system, we demonstrate that a down-conversion source in a Poissonian mode of operation can largely enhance the performance of decoy-state quantum key distribution systems. This makes the down-conversion-based decoy-state system an interesting alternative to current technological implementations based on faint-laser pulses.

  • 184. Yu, Huakang
    et al.
    Fang, Wei
    Gu, Fuxing
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Yang, Zongyin
    Tong, Limin
    Longitudinal Lorentz force on a subwavelength-diameter optical fiber2011Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 83, nr 5, s. 053830-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze the longitudinal Lorentz forces that a propagating continuous-wave light exerts on a subwavelength-diameter optical fiber. Our theoretical results show that, during the propagating process, the guided light exerts no net time-averaged force on the fiber. Via numerical simulation, we find a significant overall pull force of 0.4 pN/mW acting on a 450-nm-diam fiber tip at a wavelength of 980 nm due to the scattering of the end face and a calculated force distribution reveals the feature of a near-field accumulation. Our results may be helpful to the configuration of optomechanical components or devices based on these fibers.

  • 185.
    Yu, Zhenhua
    et al.
    Niels Bohr Inst, Copenhagen O, Denmark ; Ohio State Univ, Columbus, OH USA ; Tsinghua Univ, Beijing, Peoples R China .
    Pethick, Christopher J.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Induced interactions in dilute atomic gases and liquid helium mixtures2012Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 85, nr 6, s. 063616-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In dilute mixtures of two atomic gases, interactions between two minority atoms acquire a contribution due to interaction with the majority component. Using thermodynamic arguments, we derive expressions for this induced interaction for both fermions and bosons for arbitrary strength of the interaction between the two components. Implications of the work for the theory of dilute solutions of He-3 in liquid He-4 are discussed.

  • 186. Zhang, H. Q.
    et al.
    Akram, N.
    Soroka, Inna L.
    Physics Department, Stockholm University, Sweden.
    Trautmann, C.
    Schuch, R.
    Transmission of highly charged ions through mica nanocapillaries of rhombic cross section2012Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, nr 2, s. 022901-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The angular distributions of Ne7 + ions transmitted at various kinetic energies of 7-70 keV through muscovite mica nanocapillaries of rhombic cross section are measured. It is found that the transmitted ion beams form a rectangular shape at tilt angles that are small compared to those given by the aspect ratio, i.e., the capillary geometrical opening angle. This shape is retained for all ion energies, but its size changes. The time evolution of the transmitted angular distributions shows that the characteristic profile occurs instantaneously and remains in the stationary state of the transmission, whereas it shifts with the increase of the accumulated incident charge. At tilt angles of the capillaries larger than their aspect ratio, the shape in the transmission profile gets distorted from the rectangle by the deposited charge. Combined with trajectory simulations we show the observed shaping effect is due to the image force seen by the ions, interplaying with a deflection by the deposited charge on the capillary walls.

  • 187. Zhang, Song Bin
    et al.
    Kimberg, Victor
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. Siberian Federal University, Russian Federation.
    Rohringer, Nina
    Nonlinear resonant Auger spectroscopy in CO using an x-ray pump-control scheme2016Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 94, nr 6, artikkel-id 06413Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present paper we propose nonlinear femtosecond x-ray pump-probe spectroscopy to study the vibrational dynamics of a core-excited molecular state and discuss numerical results in CO. A femtosecond pump resonantly excites the carbon core-excited 1s-1π∗ state of the CO molecule. A second strong probe (control) pulse is applied at variable delay and is resonantly coupled to a valence excited state of the molecule. The strong nonlinear coupling of the control pulse induces Rabi flopping between the two electronic states. During this process, a vibrational wave packet in the core-excited state is created, which can be effectively manipulated by changing the time delay between pump and control pulses. We present an analysis of the resonant Auger electron spectrum and the transient absorption or emission spectrum on the pump transition and discuss their information content for reconstruction of the vibrational wave packet.

  • 188. Zhou, Z. -Q
    et al.
    Liu, X.
    Kedem, Yaron
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Cui, J. -M
    Li, Z. -F
    Hua, Y. -L
    Li, C. -F
    Guo, G. -C
    Experimental observation of anomalous trajectories of single photons2017Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 95, nr 4, artikkel-id 042121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A century after its conception, quantum mechanics still hold surprises that contradict many "common sense" notions. The contradiction is especially sharp in case one consider trajectories of truly quantum objects such as single photons. From a classical point of view, trajectories are well defined for particles, but not for waves. The wave-particle duality forces a breakdown of this dichotomy and quantum mechanics resolves this in a remarkable way: Trajectories can be well defined, but they are utterly different from classical trajectories. Here, we give an operational definition to the trajectory of a single photon by introducing a technique to mark its path using its spectral composition. The method demonstrates that the frequency degree of freedom can be used as a bona fide quantum measurement device (meter). The analysis of a number of setups, using our operational definition, leads to anomalous trajectories which are noncontinuous and in some cases do not even connect the source of the photon to where it is detected. We carried out an experimental demonstration of these anomalous trajectories using a nested interferometer. We show that the two-state vector formalism provides a simple explanation for the results. © 2017 American Physical Society.

  • 189. Zwiller, Valéry
    et al.
    Jonsson, Per
    Blom, Hans
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Jeppesen, Sören
    Pistol, Mats-Erik
    Samuelson, Lars
    Katznelson, A. A.
    Kotelnikov, E. Yu.
    Evtikhiev, Vadim
    Björk, Gunnar
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Correlation spectroscopy of excitons and biexcitons on a single quantum dot2002Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 66, nr 2, s. 053814-053814-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the observation of antibunched emission from single self-assembled InAs quantum dots under various conditions. We have measured the correlation function of the photon emission pertaining to single emission lines from single quantum dots under continuous and pulsed laser excitation, as well as under continuous white light excitation. The measurements were performed under different excitation intensities at liquid helium temperatures on two samples with distinct structures. At higher temperatures ~30 K!, an antibunching dip was still observed. We have also observed antibunching on a second emission line in the quantum dot spectrum, attributed to the biexciton, demonstrating the possibility of generating photon pairs with a single quantum dot. Polarization correlations on the biexciton and exciton line were also measured in an attempt to generate entangled photon pairs.

1234 151 - 189 of 189
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf