The backscattering enhancement effect

Vinogradov, A. G.; Gurvich, A. S.; Kashkarov, S. S.; Kravtsov, Yu. A.; Tatarskiǐ, V. I.

doi:10.1070/pu1987v030n08abeh002951

Cited by 10 publications

(15 citation statements)

References 1 publication

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“…Although the findings of Ref.[6] are certainly reasonable, a direct real-time simulation which avoids the possibly troublesome analytic continuation is desirable. Furthermore, a real-time simulation needs not rely on the Kubo formula and allows for direct computations of nonequilibrium transport and noise properties beyond the reach of previous methods.Common to all real-time QMC simulations is the ubiquitous and fundamental dynamical sign problem [10][11][12][13][14][15]. It arises in the stochastic summation over the system paths when the real-time propagators are oscillatory.…”

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confidence: 99%

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Dynamical Simulation of Transport in One-Dimensional Quantum Wires

1995

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Transport of single-channel spinless interacting fermions (Luttinger liquid) through a barrier has been studied by numerically exact quantum Monte Carlo methods. A novel stochastic integration over the real-time paths allows for direct computation of nonequilibrium conductance and noise properties. We have examined the low-temperature scaling of the conductance in the crossover region between a very weak and an almost insulating barrier.PACS numbers: 72.10. 73.40.Gk Studies of transport in one-dimensional (1D) interacting Fermi systems have gathered novel physical insights and led to the development of several new techniques over the past few years. Instead of the usual Fermi liquid theory, the low-temperature properties of an idealized 1D quantum wire are described by the Luttinger liquid model [1,2]. Remarkable transport behaviors are expected for a Luttinger liquid in the presence of impurities or barriers, and several interesting theoretical [3][4][5][6][7] and experimental [8,9] studies have emerged recently. In this Letter, we describe a real-time quantum Monte Carlo (QMC) method that enables us to directly address the dynamics of a Luttinger liquid, and use it to investigate the low-temperature transport properties of a 1D quantum wire.So far the only numerical approach to this problem has been the one given by Moon et al. [6]. These workers examined transport in a Luttinger liquid using Euclideantime QMC simulations by analytically continuing numerical data to real time with Padé approximants. Mathematically, this analytic continuation is ill-posed and small statistical errors in the imaginary-time data could be magnified immensely [10]. Physically, imaginarytime data collected at low temperatures contain predominantly ground-state information whereas real-time dynamics is controlled by the excitation spectrum. Although the findings of Ref.[6] are certainly reasonable, a direct real-time simulation which avoids the possibly troublesome analytic continuation is desirable. Furthermore, a real-time simulation needs not rely on the Kubo formula and allows for direct computations of nonequilibrium transport and noise properties beyond the reach of previous methods.Common to all real-time QMC simulations is the ubiquitous and fundamental dynamical sign problem [10][11][12][13][14][15]. It arises in the stochastic summation over the system paths when the real-time propagators are oscillatory. The quantum-mechanical interference between different paths leads to a vanishing signal-to-noise ratio at very long real times and the simulation becomes effectively unstable. However, it is generally possible to treat intermediate-to-long times by employing a partial summation scheme [14] which reduces the effective number of variables subject to the Monte Carlo sampling. If guided by physical intuition, such a partial summation scheme can largely circumvent the dynamical sign problem. Previous applications to dissipative tight-binding models in the quantum-chemical context [14,15] have demonstrated the practical usefu...

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confidence: 99%

“…Common to all real-time QMC simulations is the ubiquitous and fundamental dynamical sign problem [10][11][12][13][14][15]. It arises in the stochastic summation over the system paths when the real-time propagators are oscillatory.…”

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confidence: 99%

Dynamical Simulation of Transport in One-Dimensional Quantum Wires

1995

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“…This phenomenon, valid for reflection from a flat surface, takes place just in the vicinity of the surface. Similar phenomena could be observed at radiation reflection from a curved surface (so called 'whispering modes') [69]. Strong radiation redistribution also takes place behind capillary systems (which is actually a simple example of the curved surface system); some structural features in the distribution are due to the geometry of the system (typically, hexagon type in the transverse cross section).…”

Section: X-ray and Neutron Channeling In Micro-and Nanoguidesmentioning

confidence: 81%

Advanced Channeling Technologies in Plasma and Laser Fields

Dabagov

2018

EPJ Web of Conferences

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Abstract. Channeling is the phenomenon well known in the world mostly related to the motion of the beams of charged particles in aligned crystals. However, recent studies have shown the feasibility of channeling phenomenology application for description of other various mechanisms of interaction of charged as well as neutral particle beams in solids, plasmas and electromagnetic fields covering the research fields from crystal based undulators, collimators and accelerators to capillary based X-ray and neutron optical elements. This brief review is devoted to the status of channeling-based researches at different centers within international and national collaborations. Present and future possible developments in channeling tools applied to electron interactions in strong plasma and laser fields will be analyzed.

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“…The x-ray optical guiding effect can be obtained by employing a simple curved (and concave) mirror geometry. This type of x-ray waveguide using the whispering gallery (WG) effect was suggested by Vinogradov et al (1982) to realize the transportation and deflection of x-ray beams. Fig.…”

Section: Whispering-gallery Waveguidementioning

confidence: 99%

Enhancement of the Refl-EXAFS sensitivity using the whispering gallery effect

Sv²,

Lee³

1999

J Synchrotron Radiat

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A new approach to enhancing the sensitivity for the reflection EXAFS signal is described. A method that uses the whispering gallery effect was realized in principle, implementing the optical guiding effect by a simple curved-mirror geometry. The multiple total reflection (MTR) phenomenon highly increases x-ray interaction with the waveguide surface and hence offers higher sensitivity compared to conventional (single reflection) REFL-EXAFS. The Ge K-edge REFL-EXAFS measurements were performed using both the MTR and conventional (single reflection) techniques for a GeO2 3 ,~, thick film grown on a silica mirror. The MTR technique allows one to achieve about 20-fold gain in the signal-to-background ratio compared to the conventional technique.

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The backscattering enhancement effect

Cited by 10 publications

References 1 publication

Dynamical Simulation of Transport in One-Dimensional Quantum Wires

Dynamical Simulation of Transport in One-Dimensional Quantum Wires

Advanced Channeling Technologies in Plasma and Laser Fields

Enhancement of the Refl-EXAFS sensitivity using the whispering gallery effect

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