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1. Quadrature coherence scale driven fast decoherence of bosonic quantum field states

Author

Anaelle Hertz, Stephan De Bièvre, Laboratoire Paul Painlevé - UMR 8524 (LPP), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Paradyse, Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Inria Lille - Nord Europe, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), This work was supported in part by the Labex CEMPI (ANR-11-LABX-0007-01) and by the Nord-Pas de Calais Regional Council and FEDER through the Contrat de Projets Etat-R´egion (CPER). SDB thanks Prof. H. Spohn and J.C. Garreau for illuminating discussions on the subject matter of the paper. SDB thanks the CRM, where this work was initiated, for its hospitality in October-November 2018., ANR-11-LABX-0007,CEMPI,Centre Européen pour les Mathématiques, la Physique et leurs Interactions(2011), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Laboratoire Paul Painlevé (LPP), Systèmes de particules et systèmes dynamiques (Paradyse), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM], and Laboratoire Paul Painlevé [LPP]

Subjects
Coupling, Physics, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Quantum decoherence, etc, General Physics: Statistical and Quantum Mechanics, General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Measure (mathematics), [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Quadrature (mathematics), Quantum Information, Quantum mechanics, 0103 physical sciences, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Wigner distribution function, Quantum field theory, Quantum information, 010306 general physics, Quantum Physics (quant-ph), Coherence (physics)
Abstract

We introduce, for each state of a bosonic quantum field, its quadrature coherence scale (QCS), a measure of the range of its quadrature coherences. Under coupling to a thermal bath, the purity and QCS are shown to decrease on a time scale inversely proportional to the QCS squared. The states most fragile to decoherence are therefore those with quadrature coherences far from the diagonal. We further show a large QCS is difficult to measure since it induces small scale variations in the state's Wigner function. These two observations imply a large QCS constitutes a mark of "macroscopic coherence". Finally, we link the QCS to optical classicality: optical classical states have a small QCS and a large QCS implies strong optical nonclassicality., 12 pages, 5 figures. New version to match the published version. Minor errors were corrected

Published
2020
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2. Autodyne effect application for stability analysis of the steady-state mode of UHF oscillating systems

Author

Sergey M. Smolskiy, A. P. Chupahin, V. Ya. Noskov, A. S. Vasiliev, K. A. Ignatkov, G. P. Ermak, and The present paper is prepared in accordance with an Agreement on scientific-technological cooperation between IRE NASU, UrFU and NRU 'MPEI', as well as at financial support of Russian Federation Government, order No. 211, contract # 02.A03.21.0006.

Subjects
010302 applied physics, Physics, Coupling, Steady state, Autodyne, Mode (statistics), autodyne, autodyne characteristics, autodyne response, double-diode autodyne, mutual locking, stability, partial oscillator, 020206 networking & telecommunications, 02 engineering and technology, Mechanics, 01 natural sciences, Stability (probability), Ultra high frequency, Uhf oscillators, Control theory, Q factor, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering
Abstract

The autodyne characteristics are oifered to use for steady-state stability analysis of the UHF oscillators. Theoretical substantiation of the proposed method is performed on an example of the oscillating system's mathematical model presented in the form of two mutually-locked partial oscillators under a condition of strong coupling between them. Peculiarities of stable functioning zones for oscillating systems are described at different partial oscillator parameters and for various conditions of their mutual coupling. Experimental investigations are performed based on the 8mm-wavelength range double-diode oscillator.

Published
2017

3. Signal analysis of a double-diode autodyne

Author

A. P. Chupahin, G. P. Ermak, V. Ya. Noskov, K. A. Ignatkov, Sergey M. Smolskiy, A. S. Vasiliev, and The present paper is prepared in accordance with an Agreement on scientific-technological cooperation between IRE NASU, UrFU and NRU 'MPEI', as well as at financial support of Russian Federation Government, order No. 211, contract # 02.A03.21.0006.

Subjects
010302 applied physics, Coupling, Physics, Signal processing, Autodyne, business.industry, Acoustics, Electrical engineering, 020206 networking & telecommunications, 02 engineering and technology, Flange, 01 natural sciences, Signal, law.invention, autodyne, autodyne signal, autodyne response, double-diode autodyne, mutual locking, partial oscillator, law, Q factor, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Radar, business, Diode
Abstract

Analysis results of autodyne signals of the double-diode oscillator, which is under influence of the proper reflected emission from the moving object, are presented. The analysis is performed on the base of the autodyne mathematical model presented in the form of a system of two mutually-locked partial oscillators under condition of strong mutual coupling. Peculiarities of signal formation are considered for various parameters of partial oscillators and coupling conditions. Experimental data are obtained for the 8mm-range Gunn double-diode oscillator of the flange type.

Published
2017

4. Influence of the autodyne oscillator coupling degree with antenna upon its transfer and noise characteristics

Author

V. Ya. Noskov, A. P. Chupahin, G. P. Ermak, K. A. Ignatkov, Sergey M. Smolskiy, A. S. Vasiliev, and The present paper is prepared in accordance with an Agreement on scientific-technological cooperation between IRE NASU, UrFU and NRU 'MPEI', as well as at financial support of Russian Federation Government, order No. 211, contract # 02.A03.21.0006.

Subjects
010302 applied physics, Coupling, Physics, Autodyne, business.industry, Acoustics, autodyne, autodyne response, impedance characteristic, autodyne amplification factor, autodyne frequency deviation, UHF oscillator, Electrical engineering, 020206 networking & telecommunications, 02 engineering and technology, Frequency deviation, 01 natural sciences, Noise (electronics), 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Antenna (radio), Driven element, business, Electrical impedance, Gunn diode
Abstract

Analysis results of coupling degree influence of the autodyne oscillator with an antenna are presented together with influence of the impedance characteristic type (soft or rigid) of the active element on the coefficients of autodyne amplification, autodyne frequency deviation and power transfer as well as on the noise parameters and characteristics. Analytical and numerical calculations of above-mentioned parameters and characteristics are performed, and results of experimental investigations of the 8mm-range Gunn diode autodyne are given.

Published
2017