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

arXiv:1209.3683

Quantum Discord Dynamics for Two-Level Atom Initially in Thermal Equilibrium Interacting with n-Photon State

Hari Prakash, Mishra, Manoj K.

Published Sep 17, 2012• 0 citations
arXivHTMLPDF

Abstract

We investigate the quantum discord dynamics and inversion operator of a two-level atom initially in thermal equilibrium mixed state interacting with a cavity field prepared in a n-photon Fock state. We considered the Jaynes-Cummings model which is an exactly quantum mechanical model of interaction between two different quantum systems, an optical cavity in single mode n-photon Fock state and a two-level atom. The influence of interaction time and measurement basis used for calculating the conditional entropy is discussed on the evolution of the quantum discord and on its minimum. The evolution of mean value of inversion operator with interaction is also discussed. It is found that the quantum discord and inversion both shows oscillatory behaviour and also shows the phenomenon of beats with interaction time. For a given initial cavity photon Fock state the beat period of minimum quantum discord is one half of that for inversion operator. However, as the number of photons in cavity increases the frequency of oscillations of quantum discord and inversion increases.

DOI
10.48550/arxiv.1209.3683

Related papers

Classical correlation and quantum discord mediated by cavity in two coupled qubits

Chengzhi Wang, Chun-Xian Li, Liu-Ying Nie +1 more

We study the dynamics of classical correlation and quantum discord of two coupled two-level atoms interacting with a cavity initially in vacuum, coherent and thermal equilibrium states, respectively. The interplay between the atom–atom coupling and mean number of photons is considered. We find that, for a cavity in a vacuum state, classical correlation or quantum discord shows a sudden change in behaviour during the evolution, and evolves periodically for zero and very large qubit–qubit couplings. However, for coherent and thermal equilibrium states, the classical correlation and quantum discord present the phenomenon of collapse–revival when the qubit–qubit coupling is much greater than the mean number of photons. The period of collapse–revival becomes long as the qubit–qubit coupling and mean number of photons increase. The relationship between quantum discord and entanglement in the studied system is considered.

Journal of Physics B Atomic Molecular and Optical Physics•Dec 16, 2010•91 citations

Global quantum discord and von Neumann entropy in multipartite two-level atomic systems

Muklis Abdul Fattah Ibrahim, M. Usman, Khalid Khan

We have computed the global quantum discord (GQD) and von Neumann entropy (VNE) of multipartite two-level atomic systems interacting with a single-mode Fock field. We use Tavis–Cumming model. We have explored how quantum correlations and quantum entanglement evolve with time in such systems. The quantum system is prepared initially in a mixed state and different parameters are varied to see how they affect the information processing in the system. The dynamical character of the GQD and VNE show an interplay between classical and nonclassical correlations. Photons in this model play an important role to assist the GQD and VNE and we observed that the effects of the field on the GQD and VNE reside in the time evolution of the system indicating that both atom and field states have become entangled. The GQD is assisted in a nonlinear fashion with the number of photons in the system. The GQD and VNE show linear behavior with each other in the dynamics of the system. The effects of intrinsic decoherence on the dynamics of the GQD and VNE are also studied. We have extrapolated the results for a large photon number on the system. We have studied the effect of the change in the size of the system on the maximum value of GQD and VNE and we have estimated the scaling coefficients for this behavior.

arXiv:2303.13234•International Journal of Quantum Information•Jan 3, 2023•1 citation

Sudden transition between classical and quantum decoherence in dissipative cavity QED and stationary quantum discord

Qi-Liang He, Jing‐Bo Xu, Dao‐Xin Yao +1 more

We investigate the phenomenon of sudden transition between classical and quantum decoherence in the study of quantum discord for a dissipative cavity QED system, which consists of two noninteracting two-level atoms, each trapped in a dissipative cavity. It is found that the quantum discord between the two atoms, which are prepared initially in the X-type quantum states, is not destroyed by the dissipation of the cavities for a finite time interval, and the stationary quantum discord can arise in the interaction of atoms with cavities as the time approaches infinity. The transition time is sensitive to the initial state parameter of the two atoms and the mean photon number of the coherent field. Interestingly, the quantum discord between the two atoms is completely unaffected by the dissipation of the cavities if we choose the suitable value of the ratio, which depends on the decay rate of the two cavities and the atom-field coupling constant.

arXiv:1105.4041•Physical Review A•Aug 8, 2011•38 citations

Quantum correlation dynamics of two two-level atoms in common environment

He Zhi, Li Long-Wu

By exactly solving the model of two two-level atoms with dipole-dipole interaction, interacting with a common environment, quantum entanglement and quantum discord of two atoms are obtained. In this paper, the influences of the non-Markovian effect of environment, the dipole-dipole interaction of two atoms and the detunings of the central frequency of the cavity and the transition frequency of the atoms on quantum entanglement and quantum discord dynamics of two atoms are comprehensively considered. The study shows that in the non-Markovian regime and the resonant case, if two atoms are initially in the entangled state, the damping of quantum entanglement and quantum discord will be remarkably suppressed. More specially, in the off-resonant case, the disentanglement time of the two atoms can be considerably prolonged. On the other hand, if two atoms are initially in the separable state, the dipole-dipole interaction can enhance the amplitude of oscillations of quantum entanglement and quantum discord in a short time, but the steady values of quantum entanglement and quantum discord cannot be changed by the dipole-dipole interaction in the long-time limit. Finally, the different influences of the dipole-dipole interaction on quantum entanglement and quantum discord also are discussed.

Acta Physica Sinica•Jan 1, 2013•9 citations

Geometric quantum discord of a Jaynes–Cummings atom and an isolated atom

Wen-Chao Qiang, Lei Zhang, Huaping Zhang

Abstract We studied the geometric quantum discord of a quantum system consisting of a Jaynes–Cummings (JC) atom, a cavity and an isolated atom. The analytical expressions of the geometric quantum discord for two atoms, every atom with a cavity and the total system were obtained. We showed that the geometric quantum discord is not always zero when the entanglement falls to zero for a two-atom subsystem; the geometric measurement of the quantum discord of the total system developed periodically with a single frequency if the initial two-atom state was not entangled, otherwise, it oscillated with two or four frequencies according to whether the cavity was initially empty or not, respectively.

arXiv:1504.08253•Journal of Physics B Atomic Molecular and Optical Physics•Oct 28, 2015•13 citations

Entanglement and quantum discord in a double J-C model with intensity-dependent coupling

Yao-Hua Hu, Tan Yong-Gang, Qiang Liu

Considering a double J-C model with intensity-dependent coupling, we have studied the effects of the intensity-dependent coupling, the mean photon numbers and the atomic motion, on the entanglement and quantum discord between the two two-level atoms when the moving atoms are initially in a maximally entangled state and the fields are in the single-mode thermal fields. The results show that, the entanglement and quantum discord disappear and revive periodically, and can have up to their starting values after revival. A rise in cavity temperature accelerates the death of the entanglement and quantum discord. In addition, the field-mode structural parameter has a strong effect on the entanglement and quantum discord in the system. When the field-mode structural parameter takes a suitable value, the entanglement and quantum discord of the two atoms can be kept from start to finish.

Acta Physica Sinica•Jan 1, 2013•6 citations
We investigate the quantum discord dynamics and inversion operator of a two-level atom initially in thermal equilibrium mixed state interacting with a cavity field prepared in a n-photon Fock state. We considered the Jaynes-Cummings model which is an exactly quantum mechanical model of interaction between two different quantum systems, an optical cavity in single mode n-photon Fock state and a two-level atom. The influence of interaction time and measurement basis used for calculating the conditional entropy is discussed on the evolution of the quantum discord and on its minimum. The evolution of mean value of inversion operator with interaction is also discussed. It is found that the quantum discord and inversion both shows oscillatory behaviour and also shows the phenomenon of beats with interaction time. For a given initial cavity photon Fock state the beat period of minimum quantum discord is one half of that for inversion operator. However, as the number of photons in cavity increases the frequency of oscillations of quantum discord and inversion increases.
We study the dynamics of classical correlation and quantum discord of two coupled two-level atoms interacting with a cavity initially in vacuum, coherent and thermal equilibrium states, respectively. The interplay between the atom–atom coupling and mean number of photons is considered. We find that, for a cavity in a vacuum state, classical correlation or quantum discord shows a sudden change in behaviour during the evolution, and evolves periodically for zero and very large qubit–qubit couplings. However, for coherent and thermal equilibrium states, the classical correlation and quantum discord present the phenomenon of collapse–revival when the qubit–qubit coupling is much greater than the mean number of photons. The period of collapse–revival becomes long as the qubit–qubit coupling and mean number of photons increase. The relationship between quantum discord and entanglement in the studied system is considered.
We have computed the global quantum discord (GQD) and von Neumann entropy (VNE) of multipartite two-level atomic systems interacting with a single-mode Fock field. We use Tavis–Cumming model. We have explored how quantum correlations and quantum entanglement evolve with time in such systems. The quantum system is prepared initially in a mixed state and different parameters are varied to see how they affect the information processing in the system. The dynamical character of the GQD and VNE show an interplay between classical and nonclassical correlations. Photons in this model play an important role to assist the GQD and VNE and we observed that the effects of the field on the GQD and VNE reside in the time evolution of the system indicating that both atom and field states have become entangled. The GQD is assisted in a nonlinear fashion with the number of photons in the system. The GQD and VNE show linear behavior with each other in the dynamics of the system. The effects of intrinsic decoherence on the dynamics of the GQD and VNE are also studied. We have extrapolated the results for a large photon number on the system. We have studied the effect of the change in the size of the system on the maximum value of GQD and VNE and we have estimated the scaling coefficients for this behavior.
We investigate the phenomenon of sudden transition between classical and quantum decoherence in the study of quantum discord for a dissipative cavity QED system, which consists of two noninteracting two-level atoms, each trapped in a dissipative cavity. It is found that the quantum discord between the two atoms, which are prepared initially in the X-type quantum states, is not destroyed by the dissipation of the cavities for a finite time interval, and the stationary quantum discord can arise in the interaction of atoms with cavities as the time approaches infinity. The transition time is sensitive to the initial state parameter of the two atoms and the mean photon number of the coherent field. Interestingly, the quantum discord between the two atoms is completely unaffected by the dissipation of the cavities if we choose the suitable value of the ratio, which depends on the decay rate of the two cavities and the atom-field coupling constant.
By exactly solving the model of two two-level atoms with dipole-dipole interaction, interacting with a common environment, quantum entanglement and quantum discord of two atoms are obtained. In this paper, the influences of the non-Markovian effect of environment, the dipole-dipole interaction of two atoms and the detunings of the central frequency of the cavity and the transition frequency of the atoms on quantum entanglement and quantum discord dynamics of two atoms are comprehensively considered. The study shows that in the non-Markovian regime and the resonant case, if two atoms are initially in the entangled state, the damping of quantum entanglement and quantum discord will be remarkably suppressed. More specially, in the off-resonant case, the disentanglement time of the two atoms can be considerably prolonged. On the other hand, if two atoms are initially in the separable state, the dipole-dipole interaction can enhance the amplitude of oscillations of quantum entanglement and quantum discord in a short time, but the steady values of quantum entanglement and quantum discord cannot be changed by the dipole-dipole interaction in the long-time limit. Finally, the different influences of the dipole-dipole interaction on quantum entanglement and quantum discord also are discussed.
Abstract We studied the geometric quantum discord of a quantum system consisting of a Jaynes–Cummings (JC) atom, a cavity and an isolated atom. The analytical expressions of the geometric quantum discord for two atoms, every atom with a cavity and the total system were obtained. We showed that the geometric quantum discord is not always zero when the entanglement falls to zero for a two-atom subsystem; the geometric measurement of the quantum discord of the total system developed periodically with a single frequency if the initial two-atom state was not entangled, otherwise, it oscillated with two or four frequencies according to whether the cavity was initially empty or not, respectively.
Considering a double J-C model with intensity-dependent coupling, we have studied the effects of the intensity-dependent coupling, the mean photon numbers and the atomic motion, on the entanglement and quantum discord between the two two-level atoms when the moving atoms are initially in a maximally entangled state and the fields are in the single-mode thermal fields. The results show that, the entanglement and quantum discord disappear and revive periodically, and can have up to their starting values after revival. A rise in cavity temperature accelerates the death of the entanglement and quantum discord. In addition, the field-mode structural parameter has a strong effect on the entanglement and quantum discord in the system. When the field-mode structural parameter takes a suitable value, the entanglement and quantum discord of the two atoms can be kept from start to finish.