arXiv subjects

M. V. Lebedev

Publications and source records attributed to M. V. Lebedev.

9 recordsLinked to original sources

arXiv2020

Phase estimation algorithm for the multibeam optical metrology

Unitary Fourier transform lies at the core of the multitudinous computational and metrological algorithms. Here we show experimentally how the unitary Fourier transform-based phase estimation protocol, used namely in quantum metrology, can be translated into the classical linear optical framework. The developed setup made of beam splitters, mirrors and phase shifters demonstrates how the classical coherence, similarly to the quantum coherence, poses a resource for obtaining information about the measurable physical quantities. Our study opens route to the reliable implementation of the small-scale unitary algorithms on path-encoded qudits, thus establishing an easily accessible platform for unitary computation.

quant-ph↗

arXiv2019

Antibunching as a manifestation of light detection back action

We show that the commonly accepted treatment of the photon antibunching effect as a natural consequence of a probability distribution of particles in a particle flow contradicts the high visibility of the experimentally observed intensity correlation function.

quant-ph↗

arXiv2015

Phenomenological theory of photodetection

There are some reasons to consider the existing theory of photodetection as not complete. An attempt to improve it on the basis of the well known considerations of black body radiation given by Bose and Einstein is presented below.

quant-ph↗

arXiv2015

Fano Interference at the Excitation of Coherent Phonons: Relation between the Asymmetry Parameter and the Initial Phase of Coherent Oscillations

The theoretical assertion that the Fano asymmetry parameter and the asymptotic initial phase of a harmonic oscillator interacting with a continuum are interrelated is experimentally verified. By an example of coherent fully symmetric A1g phonons in bismuth that are excited by ultrashort laser pulses at liquid helium temperature, it is demonstrated that, for negative values of the asymmetry parameter, the asymptotic phase increases as the modulus of the parameter decreases.

cond-mat.mes-hall↗

arXiv2013

About transmission of thermal light through the surface of a body into the vacuum

The problem of the change of photon distribution of thermal light passing through the body surface into the vacuum is discussed. It is shown that the usual assumption that each photon passes through the boundary totally independent of others contradicts the expression for the fluctuation of thermal light found by A. Einstein.

quant-ph↗

arXiv2013

Multiple photon detection and the localization of light energy

It is shown that probabilities of photon detection can be found on the basis of consideration of the phase space sells filling for an ideal photon gas, which led Bose to the derivation of the Planks law. These probabilities are directly connected to photon localization properties consistent with the entropy of a dilute photon gas found by Einstein.

quant-ph↗

arXiv2012

The analogy between optical pulse compression and optical coherence transformation

A new type of an optical interferometer is discussed the phase difference between the interfering beams in which is substantially wavelength dependent. It is shown that the function measured with this device is an integral transform of the field correlation function. Possible applications for data encoding and spectral linewidth measurements are considered.

physics.optics↗

arXiv2011

Power law decay and phase rigidity for large-amplitude coherent phonons in bismuth at helium temperature: Possible evidence for transient supersolid state

Intense ultrafast laser excitation can produce transient states of condensed matter that would otherwise be inaccessible. At high excitation level, the interatomic forces can be altered resulting in an unusual lattice dynamics. Here we report the study of coherent lattice dynamics in Bi made for various excitation levels at helium temperature. We demonstrate that under certain conditions the fully symmetric phonons of large amplitude exhibit anomalous decay and phase rigidity, both of which possibly signaling the attainment of transient supersolid state.

cond-mat.mtrl-sci↗

arXiv2008

Wave-packet Formalism of Full Counting Statistics

We make use of the first-quantized wave-packet formulation of the full counting statistics to describe charge transport of noninteracting electrons in a mesoscopic device. We derive various expressions for the characteristic function generating the full counting statistics, accounting for both energy and time dependence in the scattering process and including exchange effects due to finite overlap of the incoming wave packets. We apply our results to describe the generic statistical properties of a two-fermion scattering event and find, among other features, sub-binomial statistics for nonentangled incoming states (Slater rank 1), while entangled states (Slater rank 2) may generate super-binomial (and even super-Poissonian) noise, a feature that can be used as a spin singlet-triplet detector. Another application is concerned with the constant-voltage case, where we generalize the original result of Levitov-Lesovik to account for energy-dependent scattering and finite measurement time, including short time measurements, where Pauli blocking becomes important.

cond-mat.mes-hall↗