© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Chinese Physics B

Quantum discord of two-qutrit system under quantum-jump-based feedback control*

Chang Wang, Mao-Fa Fang

Published Oct 17, 2019• 0 citations

Abstract

This paper studies quantum discord of two qutrits coupled to their own environments independently and coupled to the same environment simultaneously under quantum-jump-based feedback control. Our results show that spontaneous emission, quantum feedback parameters, classical driving, initial state, and detection efficiency all affect the evolution of quantum discord in a two-qutrit system. We find that under the condition of designing proper quantum-jump-based feedback parameters, quantum discord can be protected and prepared. In the case where two qutrits are independently coupled to their own environments, classical driving, spontaneous emission, and low detection efficiency have negative effect on the protection of quantum discord. For different initial states, it is found that the evolution of quantum discord under the control of appropriate parameters is similar. In the case where two qutrits are simultaneously coupled to the same environment, the classical driving plays a positive role in the generation of quantum discord, but spontaneous emission and low detection efficiency have negative impact on the generation of quantum discord. Most importantly, we find that the steady discord depends on feedback parameters, classical driving, and detection efficiency, but not on the initial state.

DOI: 10.1088/1674-1056/ab4e83

Related papers

Quantum discord dynamics of two atoms under different quantum feedbacks

Hui Wang, Zairong Xi

The dynamics of two identical atoms is studied, which is resonantly coupled to a single-mode cavity under two different quantum feedback controls, i.e., the symmetric feedback control and the nonsymmetric feedback control. Correspondingly, the quantum discord of the system is induced to reach steady values under these two kinds of feedback controls. Furthermore, in some cases, the steady value of quantum discord of the system under symmetric feedback control is much larger than the steady value under nonsymmetric feedback control. The situation is just the opposite when the initial state is |eg〉. It is also found that the feedback is not good for getting a high discord when the initial state is in the form of Werner-like state (d = 0).

World Congress on Intelligent Control and Automation•Jul 1, 2012•0 citations

Effect of feedback control on the dynamics of quantum discord with and without the rotating-wave approximation

Jun-Qing Cheng, Wei Wu, Jing‐Bo Xu

We investigate the effect of quantum-jump-based feedback on the dynamics of quantum discord for two noninteracting two-level atoms coupled to a single mode of the cavity field with and without the rotating-wave approximation. It is found that the counterrotating terms can be helpful for generating steady states, and the value of steady-state quantum discord can be increased to approach 1 in the long-time limit by feedback controls. Furthermore, we also explore the influence of the time evolutions of mean excitation number in total systems and atomic subsystems on the quantum correlations and show that the enhancement of mean excitation number in atomic subsystems by feedback controls leads to the high value of steady-state quantum discord.

Journal of the Optical Society of America B•Mar 1, 2017•2 citations

Noise-induced quantum correlations via quantum feedback control

Jie Song, Yan Xia, Xiudong Sun

We study a physical system for creation of quantum correlations by quantum feedback control. The system is composed of two three-level atoms, each of which interacts with one of two coupled cavities. By appropriately choosing the feedback strength, we show that an arbitrary initial state can be deterministically driven to a steady-state that has a nonzero quantum discord or entanglement. It is also found that the effect of atomic spontaneous emission on quantum correlations is suppressed efficiently by increasing the frequency detuning.

Journal of the Optical Society of America B•Feb 8, 2012•10 citations

QUANTUM DISCORD UNDER SYSTEM–ENVIRONMENT COUPLING: THE TWO-QUBIT CASE

Jin‐Shi Xu, Chuan‐Feng Li

Open quantum systems have attracted great attention, since inevitable coupling between quantum systems and their environment greatly affects the features of interest of these systems. Quantum discord, is a measure of the total nonclassical correlation in a quantum system that includes, but is not exclusive to, the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and plays an important role in many fundamental physics problems and practical quantum information tasks. There have been numerous investigations on quantum discord and its counterpart classical correlation. This short review focuses on highlighting the system–environment dynamics of two-qubit quantum discord and the influence of initial system–environment correlations on the dynamics of open quantum systems. The external control effect on the dynamics of open quantum systems are involved. Several related experimental works are discussed.

arXiv:1205.0871•International Journal of Modern Physics B•Oct 24, 2012•13 citations

Quantum discord in open quantum systems

Jin‐Shi Xu, Chuan‐Feng Li

Open quantum systems have attracted great attention, since inevitable coupling between quantum systems and their environment greatly affects the features of interest of these systems. Quantum discord, is a measure of the total nonclassical correlation in a quantum system that includes, but is not exclusive to, the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and plays an important role in many fundamental physics problems and practical quantum information tasks. There have been numerous investigations on quantum discord and its counterpart classical correlation. This short review focuses on highlighting the system-environment dynamics of two-qubit quantum discord and the influence of initial system-environment correlations on the dynamics of open quantum systems. The external control effect on the dynamics of open quantum systems are involved. Several related experimental works are discussed.

•May 4, 2012•0 citations

Quantum discord for a central two-qubit system coupled to an XY -spin-chain environment

Ben‐Qiong Liu, Bin Shao, Jian Zou

We investigate the dynamic behaviors of quantum discord for a central two-qubit system coupled to an $\mathit{XY}$-spin-chain environment. In the weak-coupling regime, we show that the quantum discord for the two central qubits can become minimized rapidly close to the critical point of a quantum phase transition. By considering the two qubits that are initially prepared in the Werner state, we study the evolution of the quantum discord and that of entanglement under the same conditions. Our results imply that entanglement can disappear completely after a finite time, while the quantum discord decreases and tends to be a stable value according to the initial-state parameter for a very-long-time interval. In this sense, the quantum discord is more robust than entanglement for the quantum system exposed to the environment. The relation between the quantum correlations and the classical correlation is also shown for two particular cases.

Physical Review A•Dec 28, 2010•59 citations

This paper studies quantum discord of two qutrits coupled to their own environments independently and coupled to the same environment simultaneously under quantum-jump-based feedback control. Our results show that spontaneous emission, quantum feedback parameters, classical driving, initial state, and detection efficiency all affect the evolution of quantum discord in a two-qutrit system. We find that under the condition of designing proper quantum-jump-based feedback parameters, quantum discord can be protected and prepared. In the case where two qutrits are independently coupled to their own environments, classical driving, spontaneous emission, and low detection efficiency have negative effect on the protection of quantum discord. For different initial states, it is found that the evolution of quantum discord under the control of appropriate parameters is similar. In the case where two qutrits are simultaneously coupled to the same environment, the classical driving plays a positive role in the generation of quantum discord, but spontaneous emission and low detection efficiency have negative impact on the generation of quantum discord. Most importantly, we find that the steady discord depends on feedback parameters, classical driving, and detection efficiency, but not on the initial state.

The dynamics of two identical atoms is studied, which is resonantly coupled to a single-mode cavity under two different quantum feedback controls, i.e., the symmetric feedback control and the nonsymmetric feedback control. Correspondingly, the quantum discord of the system is induced to reach steady values under these two kinds of feedback controls. Furthermore, in some cases, the steady value of quantum discord of the system under symmetric feedback control is much larger than the steady value under nonsymmetric feedback control. The situation is just the opposite when the initial state is |eg〉. It is also found that the feedback is not good for getting a high discord when the initial state is in the form of Werner-like state (d = 0).

We investigate the effect of quantum-jump-based feedback on the dynamics of quantum discord for two noninteracting two-level atoms coupled to a single mode of the cavity field with and without the rotating-wave approximation. It is found that the counterrotating terms can be helpful for generating steady states, and the value of steady-state quantum discord can be increased to approach 1 in the long-time limit by feedback controls. Furthermore, we also explore the influence of the time evolutions of mean excitation number in total systems and atomic subsystems on the quantum correlations and show that the enhancement of mean excitation number in atomic subsystems by feedback controls leads to the high value of steady-state quantum discord.

We study a physical system for creation of quantum correlations by quantum feedback control. The system is composed of two three-level atoms, each of which interacts with one of two coupled cavities. By appropriately choosing the feedback strength, we show that an arbitrary initial state can be deterministically driven to a steady-state that has a nonzero quantum discord or entanglement. It is also found that the effect of atomic spontaneous emission on quantum correlations is suppressed efficiently by increasing the frequency detuning.

Open quantum systems have attracted great attention, since inevitable coupling between quantum systems and their environment greatly affects the features of interest of these systems. Quantum discord, is a measure of the total nonclassical correlation in a quantum system that includes, but is not exclusive to, the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and plays an important role in many fundamental physics problems and practical quantum information tasks. There have been numerous investigations on quantum discord and its counterpart classical correlation. This short review focuses on highlighting the system–environment dynamics of two-qubit quantum discord and the influence of initial system–environment correlations on the dynamics of open quantum systems. The external control effect on the dynamics of open quantum systems are involved. Several related experimental works are discussed.

Open quantum systems have attracted great attention, since inevitable coupling between quantum systems and their environment greatly affects the features of interest of these systems. Quantum discord, is a measure of the total nonclassical correlation in a quantum system that includes, but is not exclusive to, the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and plays an important role in many fundamental physics problems and practical quantum information tasks. There have been numerous investigations on quantum discord and its counterpart classical correlation. This short review focuses on highlighting the system-environment dynamics of two-qubit quantum discord and the influence of initial system-environment correlations on the dynamics of open quantum systems. The external control effect on the dynamics of open quantum systems are involved. Several related experimental works are discussed.

We investigate the dynamic behaviors of quantum discord for a central two-qubit system coupled to an

\mathit{XY}

-spin-chain environment. In the weak-coupling regime, we show that the quantum discord for the two central qubits can become minimized rapidly close to the critical point of a quantum phase transition. By considering the two qubits that are initially prepared in the Werner state, we study the evolution of the quantum discord and that of entanglement under the same conditions. Our results imply that entanglement can disappear completely after a finite time, while the quantum discord decreases and tends to be a stable value according to the initial-state parameter for a very-long-time interval. In this sense, the quantum discord is more robust than entanglement for the quantum system exposed to the environment. The relation between the quantum correlations and the classical correlation is also shown for two particular cases.