Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Optics B Quantum and Semiclassical Optics

Quantum properties of a single-mode dissipative amplifier against Schrödinger-cat states

Faisal A. A. El-Orany, Jan Peřina, Vlasta Peřinová, M. Sebawe Abdalla

Published Apr 5, 2002• 5 citations
Publisher

Abstract

In this paper we investigate the single-mode properties (Wigner function, photon-number distribution and quadrature squeezing) of a dissipative parametric amplifier when the signal and idler modes are initially prepared in the Schrödinger-cat states. We show that there are two sources producing decoherence in the system, which are spontaneous pump photon decay and interaction with the environment. For the latter case, the system collapses to both statistical mixture states as well as thermal states governed by the interaction parameters.

DOI
10.1088/1464-4266/4/3/369

Related papers

Robustness of nonclassical superposition states against decoherence

Faisal A. A. El-Orany

We make a comparative study of quadrature squeezing, photon-number distribution, and Wigner function in a decayed quantum system. Specifically, for a field mode prepared initially the Schr\"odinger cat states interacting with a zero-temperature environment, we show that the rate of reduction of the nonclassical effects in this system is proportional to the occurrence of the decoherence process.

arXiv:1107.3607•Physical Review A•Apr 2, 2002•13 citations

Amplification of Schrödinger-cat state in a degenerate optical parametric amplifier

Radim Filip

Amplification of the Schrödinger-cat state (even coherent-state superposition) can be accompanied by its non-exponential decoherence and strong squeezing effect in the degenerate optical parametric amplifier. In the classical pump approximation and small thermal noise limit, the Wigner function behaviour illustrates that this non-exponential effect is induced by the phase-selective character of amplification. The non-exponential decoherence is much slower, in contrast with phase-unselective amplification exhibiting faster exponential decay. Thus, if one is able to produce the Schrödinger-cat state with at least a small amplitude, then it can be partially amplified with only a weak decoherence effect.

Journal of Optics B Quantum and Semiclassical Optics•Jan 25, 2001•16 citations

Optical Schrödinger cat states in one mode and two coupled modes subject to environments

Xinyu Zhao, Z. C. Shi, M. Qin +1 more

Taking the decoherence into account, we investigate nonclassical features of the optical Schr\"odinger cat states in one-mode and two-coupled-modes systems with two-photon driving. In the one-mode system, the relationship between the Schr\"odinger cat states and the system parameters is derived. We observe that in the presence of single-photon decay the steady states would be a mixture of Schr\"odinger cat states. The dynamics and steady states of such a cat versus single-photon decay are examined. In the two-coupled-modes cases with linear and nonlinear couplings, the dynamics of entanglement and mutual information are examined with two different initial states and single-photon decay. Compared to the linear coupling case, more complicated structure appears in the Wigner function in the nonlinear coupling case. The joint quadrature distributions are also explored. Such nonclassical states can be used not only in exploring the boundary between the classical and the quantum worlds but also in quantum metrology and quantum information processing.

arXiv:1611.08146•Physical Review A•Jul 13, 2017•8 citations

Amplification of Schrödinger-cat state: distinguishability and interference in phase space

Radim Filip, Jan Peřina

Amplification and cloning of the Schrödinger-cat state (even coherent-state superposition) in the optical nondegenerate parametric amplifier are analysed. In the long-time limit, distinguishability and interference in the marginal probability distributions of the Schrödinger-cat state cannot be preserved simultaneously during amplification. The mutual ratio between distinguishability and interference can be controlled by the squeezed vacuum state injected in the idler mode. Thus only one of either quantum interference of indistinguishable states or distinguished states without interference can be obtained on the output of the amplifier. The purity of the initial state in the signal mode disappears during the amplification for both cases, even if the interference is preserved. Thus the interference in the marginal probability distribution is connected with indistinguishability in the phase space rather than with purity of the state. On the other hand, the nonclassical oscillations in the photon-number distribution vanish simultaneously, as the state is more mixed, irrespective of the existence of the interference.

Journal of Optics B Quantum and Semiclassical Optics•Mar 14, 2001•8 citations

Función de Wigner y Decoherencia Cuántica para Sistemas Átomo-Campo en Cavidades QED

Juan Pablo Cuartas, Herbert Vinck Posada, Boris A. Rodríguez

ABSTRACT: The processes of quantum decoherence in QED cavities have been extensively studied in the last decade, both experimentally by Haroche, Raimond et. al., as theoretically by Nemes, Davidovich et. to the. We present here the dynamics of the Wigner function for a system consisting of a two-level atom and a cavity in a dissipative environment, using a numerical integration scheme that allows us to consider initial Squeezed and Schrodinger's Cat States. The interaction between the atom and the single-mode field is considered by a dispersive model, that is, the interaction in the Hamiltonian of Jaynes-Cummings appears as a small disturbance. The interest is focused both on the quantum characteristics of the dispersive approach (preparation of mesoscopic states) and on the aspects that characterize dynamics and dissipation. In particular, the gradual loss of quantum coherence is observed through the use of the Wigner function, where the disappearance of the interference regions of the initial quantum states is evidenced.

Revista de la Sociedad Colombiana de Física•Jan 1, 2009•0 citations

Overcoming decoherence of Schrödinger cat states formed in a cavity using squeezed-state inputs

Run Yan Teh, P. D. Drummond, M. D. Reid

A cat-state is a superposition of two coherent states with amplitudes $α_{0}$ and $-α_{0}$. Recent experiments create cat states in a microwave cavity field using superconducting circuits. As with degenerate parametric oscillation (DPO) in an adiabatic and highly nonlinear limit, the states are formed in a signal cavity mode via a two-photon dissipative process induced by the down conversion of a pump field to generate pairs of signal photons. The damping of the signal and the presence of thermal fluctuations rapidly decoheres the state, and the effect on the dynamics is to either destroy the possibility of a cat state, or else to sharply reduce the lifetime and size of the cat-states that can be formed. In this paper, we study the effect on both the DPO and microwave systems of a squeezed reservoir coupled to the cavity. While the threshold nonlinearity is not altered, we show that the use of squeezed states significantly lengthens the lifetime of the cat states. This improves the feasibility of generating cat states of large amplitude and with a greater degree of quantum macroscopic coherence, which is necessary for many quantum technology applications. Using current experimental parameters for the microwave set-up, which requires a modified Hamiltonian, we further demonstrate how squeezed states enhance the quality of the cat states that could be formed in this regime. Squeezing also combats the significant decoherence due to thermal noise, which is relevant for microwave fields at finite temperature. By modeling a thermal squeezed reservoir, we show that the thermal decoherence of the dynamical cat states can be inhibited by a careful control of the squeezing of the reservoir. To signify the quality of the cat state, we consider different signatures including fringes and negativity, and the $C_{l_{1}}$ measure of quantum coherence.

arXiv:2006.12725•Physical Review Research•Dec 17, 2020•34 citations
In this paper we investigate the single-mode properties (Wigner function, photon-number distribution and quadrature squeezing) of a dissipative parametric amplifier when the signal and idler modes are initially prepared in the Schrödinger-cat states. We show that there are two sources producing decoherence in the system, which are spontaneous pump photon decay and interaction with the environment. For the latter case, the system collapses to both statistical mixture states as well as thermal states governed by the interaction parameters.
Amplification of the Schrödinger-cat state (even coherent-state superposition) can be accompanied by its non-exponential decoherence and strong squeezing effect in the degenerate optical parametric amplifier. In the classical pump approximation and small thermal noise limit, the Wigner function behaviour illustrates that this non-exponential effect is induced by the phase-selective character of amplification. The non-exponential decoherence is much slower, in contrast with phase-unselective amplification exhibiting faster exponential decay. Thus, if one is able to produce the Schrödinger-cat state with at least a small amplitude, then it can be partially amplified with only a weak decoherence effect.
Taking the decoherence into account, we investigate nonclassical features of the optical Schr\"odinger cat states in one-mode and two-coupled-modes systems with two-photon driving. In the one-mode system, the relationship between the Schr\"odinger cat states and the system parameters is derived. We observe that in the presence of single-photon decay the steady states would be a mixture of Schr\"odinger cat states. The dynamics and steady states of such a cat versus single-photon decay are examined. In the two-coupled-modes cases with linear and nonlinear couplings, the dynamics of entanglement and mutual information are examined with two different initial states and single-photon decay. Compared to the linear coupling case, more complicated structure appears in the Wigner function in the nonlinear coupling case. The joint quadrature distributions are also explored. Such nonclassical states can be used not only in exploring the boundary between the classical and the quantum worlds but also in quantum metrology and quantum information processing.
Amplification and cloning of the Schrödinger-cat state (even coherent-state superposition) in the optical nondegenerate parametric amplifier are analysed. In the long-time limit, distinguishability and interference in the marginal probability distributions of the Schrödinger-cat state cannot be preserved simultaneously during amplification. The mutual ratio between distinguishability and interference can be controlled by the squeezed vacuum state injected in the idler mode. Thus only one of either quantum interference of indistinguishable states or distinguished states without interference can be obtained on the output of the amplifier. The purity of the initial state in the signal mode disappears during the amplification for both cases, even if the interference is preserved. Thus the interference in the marginal probability distribution is connected with indistinguishability in the phase space rather than with purity of the state. On the other hand, the nonclassical oscillations in the photon-number distribution vanish simultaneously, as the state is more mixed, irrespective of the existence of the interference.
ABSTRACT: The processes of quantum decoherence in QED cavities have been extensively studied in the last decade, both experimentally by Haroche, Raimond et. al., as theoretically by Nemes, Davidovich et. to the. We present here the dynamics of the Wigner function for a system consisting of a two-level atom and a cavity in a dissipative environment, using a numerical integration scheme that allows us to consider initial Squeezed and Schrodinger's Cat States. The interaction between the atom and the single-mode field is considered by a dispersive model, that is, the interaction in the Hamiltonian of Jaynes-Cummings appears as a small disturbance. The interest is focused both on the quantum characteristics of the dispersive approach (preparation of mesoscopic states) and on the aspects that characterize dynamics and dissipation. In particular, the gradual loss of quantum coherence is observed through the use of the Wigner function, where the disappearance of the interference regions of the initial quantum states is evidenced.
A cat-state is a superposition of two coherent states with amplitudes α0α_{0}α0​ and −α0-α_{0}−α0​. Recent experiments create cat states in a microwave cavity field using superconducting circuits. As with degenerate parametric oscillation (DPO) in an adiabatic and highly nonlinear limit, the states are formed in a signal cavity mode via a two-photon dissipative process induced by the down conversion of a pump field to generate pairs of signal photons. The damping of the signal and the presence of thermal fluctuations rapidly decoheres the state, and the effect on the dynamics is to either destroy the possibility of a cat state, or else to sharply reduce the lifetime and size of the cat-states that can be formed. In this paper, we study the effect on both the DPO and microwave systems of a squeezed reservoir coupled to the cavity. While the threshold nonlinearity is not altered, we show that the use of squeezed states significantly lengthens the lifetime of the cat states. This improves the feasibility of generating cat states of large amplitude and with a greater degree of quantum macroscopic coherence, which is necessary for many quantum technology applications. Using current experimental parameters for the microwave set-up, which requires a modified Hamiltonian, we further demonstrate how squeezed states enhance the quality of the cat states that could be formed in this regime. Squeezing also combats the significant decoherence due to thermal noise, which is relevant for microwave fields at finite temperature. By modeling a thermal squeezed reservoir, we show that the thermal decoherence of the dynamical cat states can be inhibited by a careful control of the squeezing of the reservoir. To signify the quality of the cat state, we consider different signatures including fringes and negativity, and the Cl1C_{l_{1}}Cl1​​ measure of quantum coherence.