TY  - JOUR
AU  - Andreev, Vladimir A.
AU  - Davidović, Milena D.
AU  - Davidović, Ljubica D.
AU  - Davidović, Miloš D.
AU  - Davidović, Dragomir M.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9164
AB  - We consider the system of N two-level atoms, of which N0 atoms are unexcited and N1 are excited. This system of N two-level atoms, which forms a linear quantum amplifier, interacts with a single-mode electromagnetic field. The problem of amplification of the L-photon states using such an amplifier is studied. The evolution of the electromagnetic field density matrix is described by the master equation for the field under amplification. The dynamics of this process is such that it can be described as the transformation of the scale of the phase space. The exact solution of the master equation is expressed using the transformed Husimi function of the L-quantum state of the harmonic oscillator. The properties of this function are studied and using it the average photon number and its fluctuations in the amplified state are found. © 2021, Editura Academiei Romane. All rights reserved.
T2  - Romanian Reports in Physics
T1  - Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier
VL  - 73
IS  - 1
SP  - 102
UR  - https://hdl.handle.net/21.15107/rcub_vinar_9164
ER  - 

@article{
author = "Andreev, Vladimir A. and Davidović, Milena D. and Davidović, Ljubica D. and Davidović, Miloš D. and Davidović, Dragomir M.",
year = "2021",
abstract = "We consider the system of N two-level atoms, of which N0 atoms are unexcited and N1 are excited. This system of N two-level atoms, which forms a linear quantum amplifier, interacts with a single-mode electromagnetic field. The problem of amplification of the L-photon states using such an amplifier is studied. The evolution of the electromagnetic field density matrix is described by the master equation for the field under amplification. The dynamics of this process is such that it can be described as the transformation of the scale of the phase space. The exact solution of the master equation is expressed using the transformed Husimi function of the L-quantum state of the harmonic oscillator. The properties of this function are studied and using it the average photon number and its fluctuations in the amplified state are found. © 2021, Editura Academiei Romane. All rights reserved.",
journal = "Romanian Reports in Physics",
title = "Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier",
volume = "73",
number = "1",
pages = "102",
url = "https://hdl.handle.net/21.15107/rcub_vinar_9164"
}

Andreev, V. A., Davidović, M. D., Davidović, L. D., Davidović, M. D.,& Davidović, D. M.. (2021). Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier. in Romanian Reports in Physics, 73(1), 102.
https://hdl.handle.net/21.15107/rcub_vinar_9164

Andreev VA, Davidović MD, Davidović LD, Davidović MD, Davidović DM. Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier. in Romanian Reports in Physics. 2021;73(1):102.
https://hdl.handle.net/21.15107/rcub_vinar_9164 .

Andreev, Vladimir A., Davidović, Milena D., Davidović, Ljubica D., Davidović, Miloš D., Davidović, Dragomir M., "Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier" in Romanian Reports in Physics, 73, no. 1 (2021):102,
https://hdl.handle.net/21.15107/rcub_vinar_9164 .

TY  - JOUR
AU  - Andreev, Vladimir A.
AU  - Davidović, Milena D.
AU  - Davidović, Ljubica D.
AU  - Davidović, Miloš D.
AU  - Davidović, Dragomir M.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8628
AB  - We consider a linear quantum amplifier consisting of NA two-level atoms and study the problem of amplification of N-photon states. The N-photon states are associated with N-quantum states of the harmonic oscillator. We show that the process of interaction of the electromagnetic field with atoms can be associated with some transformation of the phase space and functions defined on this phase space. We consider the Husimi functions QN(q, p) of N-quantum states of the harmonic oscillator, which are defined on the phase space, investigate transformation of these functions, and find an explicit form of the density matrix of the amplified N-photon state. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
T2  - Journal of Russian Laser Research
T1  - Linear Light Amplifier and Amplification of N-Photon States
VL  - 40
IS  - 4
SP  - 321
EP  - 327
DO  - 10.1007/s10946-019-09807-2
ER  - 

@article{
author = "Andreev, Vladimir A. and Davidović, Milena D. and Davidović, Ljubica D. and Davidović, Miloš D. and Davidović, Dragomir M.",
year = "2019",
abstract = "We consider a linear quantum amplifier consisting of NA two-level atoms and study the problem of amplification of N-photon states. The N-photon states are associated with N-quantum states of the harmonic oscillator. We show that the process of interaction of the electromagnetic field with atoms can be associated with some transformation of the phase space and functions defined on this phase space. We consider the Husimi functions QN(q, p) of N-quantum states of the harmonic oscillator, which are defined on the phase space, investigate transformation of these functions, and find an explicit form of the density matrix of the amplified N-photon state. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.",
journal = "Journal of Russian Laser Research",
title = "Linear Light Amplifier and Amplification of N-Photon States",
volume = "40",
number = "4",
pages = "321-327",
doi = "10.1007/s10946-019-09807-2"
}

Andreev, V. A., Davidović, M. D., Davidović, L. D., Davidović, M. D.,& Davidović, D. M.. (2019). Linear Light Amplifier and Amplification of N-Photon States. in Journal of Russian Laser Research, 40(4), 321-327.
https://doi.org/10.1007/s10946-019-09807-2

Andreev VA, Davidović MD, Davidović LD, Davidović MD, Davidović DM. Linear Light Amplifier and Amplification of N-Photon States. in Journal of Russian Laser Research. 2019;40(4):321-327.
doi:10.1007/s10946-019-09807-2 .

Andreev, Vladimir A., Davidović, Milena D., Davidović, Ljubica D., Davidović, Miloš D., Davidović, Dragomir M., "Linear Light Amplifier and Amplification of N-Photon States" in Journal of Russian Laser Research, 40, no. 4 (2019):321-327,
https://doi.org/10.1007/s10946-019-09807-2 . .

TY  - CONF
AU  - Davidović, Milena D.
AU  - Davidović, Miloš D.
AU  - Davidović, Ljubica D.
AU  - Andreev, Vladimir A.
AU  - Davidović, Dragomir M.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10941
AB  - Many real-world signals, occurring in everyday engineering practice are non-stationary, and as a result, their frequency components may change gradually or abruptly over time. Such signals are typically analyzed using Fourier transform, however, this type of analysis is often not sufficient to reveal the true nature of localized (in time) frequency content. This is where time-frequency analysis (TFA) can be of great help. Several approaches of TFA exist, and in this paper we use Husimi function (Gaussian smoothed Wigner function) for this purpose [1,2,3]. Both the Wigner and Husimi functions are the phase space quasidistributions in quantum mechanics [4,5]. In quantum mechanics, Husimi function of a quantum mechanical state arises when simultaneous measurement of quantum conjugated observables - coordinate and momentum, is performed. Similarly, in signal analysis, conjugated variables are time and frequency. If the measurement has the highest physically possible accuracy (as dictated by the Heisenberg uncertainty relations), then the product of standard deviations of conjugated observables equals  2 and Gaussian smoothed Wigner function for in such a way chosen parameters is known as a Husimi function (HF) [2,5]. In this paper, characteristic signals which describe behavior of several devices used in optics, microwave engineering and plasmonics were obtained via 3D electromagnetic numerical simulations. These signals, and their time and frequency evolution, were then analyzed using specifically tailored HF.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
T1  - Husimi function for time-frequency analysis in optical, microwave and plasmonics aplications
SP  - 59
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10941
ER  - 

@conference{
author = "Davidović, Milena D. and Davidović, Miloš D. and Davidović, Ljubica D. and Andreev, Vladimir A. and Davidović, Dragomir M.",
year = "2017",
abstract = "Many real-world signals, occurring in everyday engineering practice are non-stationary, and as a result, their frequency components may change gradually or abruptly over time. Such signals are typically analyzed using Fourier transform, however, this type of analysis is often not sufficient to reveal the true nature of localized (in time) frequency content. This is where time-frequency analysis (TFA) can be of great help. Several approaches of TFA exist, and in this paper we use Husimi function (Gaussian smoothed Wigner function) for this purpose [1,2,3]. Both the Wigner and Husimi functions are the phase space quasidistributions in quantum mechanics [4,5]. In quantum mechanics, Husimi function of a quantum mechanical state arises when simultaneous measurement of quantum conjugated observables - coordinate and momentum, is performed. Similarly, in signal analysis, conjugated variables are time and frequency. If the measurement has the highest physically possible accuracy (as dictated by the Heisenberg uncertainty relations), then the product of standard deviations of conjugated observables equals  2 and Gaussian smoothed Wigner function for in such a way chosen parameters is known as a Husimi function (HF) [2,5]. In this paper, characteristic signals which describe behavior of several devices used in optics, microwave engineering and plasmonics were obtained via 3D electromagnetic numerical simulations. These signals, and their time and frequency evolution, were then analyzed using specifically tailored HF.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts",
title = "Husimi function for time-frequency analysis in optical, microwave and plasmonics aplications",
pages = "59",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10941"
}

Davidović, M. D., Davidović, M. D., Davidović, L. D., Andreev, V. A.,& Davidović, D. M.. (2017). Husimi function for time-frequency analysis in optical, microwave and plasmonics aplications. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
Belgrade : Institute of Physics Belgrade., 59.
https://hdl.handle.net/21.15107/rcub_vinar_10941

Davidović MD, Davidović MD, Davidović LD, Andreev VA, Davidović DM. Husimi function for time-frequency analysis in optical, microwave and plasmonics aplications. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts. 2017;:59.
https://hdl.handle.net/21.15107/rcub_vinar_10941 .

Davidović, Milena D., Davidović, Miloš D., Davidović, Ljubica D., Andreev, Vladimir A., Davidović, Dragomir M., "Husimi function for time-frequency analysis in optical, microwave and plasmonics aplications" in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts (2017):59,
https://hdl.handle.net/21.15107/rcub_vinar_10941 .

TY  - JOUR
AU  - Andreev, Vladimir A.
AU  - Davidović, Dragomir M.
AU  - Davidović, Ljubica D.
AU  - Davidović, Milena D.
AU  - Davidović, Miloš D.
AU  - Zotov, Sergey D.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1310
AB  - We consider the Husimi Q(q, p)-functions which are quantum quasiprobability distributions on the phase space. It is known that, under a scaling transform (q; p) - GT (aiiq; aiip), the Husimi function of any physical state is converted into a function which is also the Husimi function of some physical state. More precisely, it has been proved that, if Q(q, p) is the Husimi function, the function aii(2) Q(aiiq; aiip) is also the Husimi function. We call a state with the Husimi function aii(2) Q(aiiq; aiip) the stretched state and investigate the properties of the stretched Fock states. These states can be obtained as a result of applying the scaling transform to the Fock states of the harmonic oscillator. The harmonic-oscillator Fock states are pure states, but the stretched Fock states are mixed states. We find the density matrices of stretched Fock states in an explicit form. Their structure can be described with the help of negative binomial distributions. We present the graphs of distributions of negative binomial coefficients for different stretched Fock states and show the von Neumann entropy of the simplest stretched Fock state.
T2  - Journal of Russian Laser Research
T1  - Scaling Transform and Stretched States in Quantum Mechanics
VL  - 37
IS  - 5
SP  - 434
EP  - 439
DO  - 10.1007/s10946-016-9594-4
ER  - 

@article{
author = "Andreev, Vladimir A. and Davidović, Dragomir M. and Davidović, Ljubica D. and Davidović, Milena D. and Davidović, Miloš D. and Zotov, Sergey D.",
year = "2016",
abstract = "We consider the Husimi Q(q, p)-functions which are quantum quasiprobability distributions on the phase space. It is known that, under a scaling transform (q; p) - GT (aiiq; aiip), the Husimi function of any physical state is converted into a function which is also the Husimi function of some physical state. More precisely, it has been proved that, if Q(q, p) is the Husimi function, the function aii(2) Q(aiiq; aiip) is also the Husimi function. We call a state with the Husimi function aii(2) Q(aiiq; aiip) the stretched state and investigate the properties of the stretched Fock states. These states can be obtained as a result of applying the scaling transform to the Fock states of the harmonic oscillator. The harmonic-oscillator Fock states are pure states, but the stretched Fock states are mixed states. We find the density matrices of stretched Fock states in an explicit form. Their structure can be described with the help of negative binomial distributions. We present the graphs of distributions of negative binomial coefficients for different stretched Fock states and show the von Neumann entropy of the simplest stretched Fock state.",
journal = "Journal of Russian Laser Research",
title = "Scaling Transform and Stretched States in Quantum Mechanics",
volume = "37",
number = "5",
pages = "434-439",
doi = "10.1007/s10946-016-9594-4"
}

Andreev, V. A., Davidović, D. M., Davidović, L. D., Davidović, M. D., Davidović, M. D.,& Zotov, S. D.. (2016). Scaling Transform and Stretched States in Quantum Mechanics. in Journal of Russian Laser Research, 37(5), 434-439.
https://doi.org/10.1007/s10946-016-9594-4

Andreev VA, Davidović DM, Davidović LD, Davidović MD, Davidović MD, Zotov SD. Scaling Transform and Stretched States in Quantum Mechanics. in Journal of Russian Laser Research. 2016;37(5):434-439.
doi:10.1007/s10946-016-9594-4 .

Andreev, Vladimir A., Davidović, Dragomir M., Davidović, Ljubica D., Davidović, Milena D., Davidović, Miloš D., Zotov, Sergey D., "Scaling Transform and Stretched States in Quantum Mechanics" in Journal of Russian Laser Research, 37, no. 5 (2016):434-439,
https://doi.org/10.1007/s10946-016-9594-4 . .

TY  - JOUR
AU  - Andreev, Vladimir A.
AU  - Davidović, Milena D.
AU  - Davidovic, Ljubica D.
AU  - Davidović, Miloš D.
AU  - Davidović, Dragomir M.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/643
AB  - We propose a new method for the derivation of Husimi symbols, for operators that are given in the form of products of an arbitrary number of coordinates, and momentum operators, in an arbitrary order. For such an operator, in the standard approach, one expresses coordinate and momentum operators as a linear combination of the creation and annihilation operators, and then uses the antinormal ordering to obtain the final form of the symbol. In our method, one obtains the Husimi symbol in a much more straightforward fashion, departing directly from operator explicit form without transforming it through creation and annihilation operators. With this method the mean values of some operators are found. It is shown how the Heisenberg and the Schrodinger-Robertson uncertainty relations, for position and momentum, are transformed under scale transformation (q; p) - GT (lambda q; lambda p). The physical sense of some states which can be constructed with this transformation is also discussed.
T2  - Physica Scripta
T1  - Derivation of the Husimi symbols without antinormal ordering, scale transformation and uncertainty relations
VL  - 90
IS  - 7
DO  - 10.1088/0031-8949/90/7/074023
ER  - 

@article{
author = "Andreev, Vladimir A. and Davidović, Milena D. and Davidovic, Ljubica D. and Davidović, Miloš D. and Davidović, Dragomir M.",
year = "2015",
abstract = "We propose a new method for the derivation of Husimi symbols, for operators that are given in the form of products of an arbitrary number of coordinates, and momentum operators, in an arbitrary order. For such an operator, in the standard approach, one expresses coordinate and momentum operators as a linear combination of the creation and annihilation operators, and then uses the antinormal ordering to obtain the final form of the symbol. In our method, one obtains the Husimi symbol in a much more straightforward fashion, departing directly from operator explicit form without transforming it through creation and annihilation operators. With this method the mean values of some operators are found. It is shown how the Heisenberg and the Schrodinger-Robertson uncertainty relations, for position and momentum, are transformed under scale transformation (q; p) - GT (lambda q; lambda p). The physical sense of some states which can be constructed with this transformation is also discussed.",
journal = "Physica Scripta",
title = "Derivation of the Husimi symbols without antinormal ordering, scale transformation and uncertainty relations",
volume = "90",
number = "7",
doi = "10.1088/0031-8949/90/7/074023"
}

Andreev, V. A., Davidović, M. D., Davidovic, L. D., Davidović, M. D.,& Davidović, D. M.. (2015). Derivation of the Husimi symbols without antinormal ordering, scale transformation and uncertainty relations. in Physica Scripta, 90(7).
https://doi.org/10.1088/0031-8949/90/7/074023

Andreev VA, Davidović MD, Davidovic LD, Davidović MD, Davidović DM. Derivation of the Husimi symbols without antinormal ordering, scale transformation and uncertainty relations. in Physica Scripta. 2015;90(7).
doi:10.1088/0031-8949/90/7/074023 .

Andreev, Vladimir A., Davidović, Milena D., Davidovic, Ljubica D., Davidović, Miloš D., Davidović, Dragomir M., "Derivation of the Husimi symbols without antinormal ordering, scale transformation and uncertainty relations" in Physica Scripta, 90, no. 7 (2015),
https://doi.org/10.1088/0031-8949/90/7/074023 . .