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

International Journal of Modern Physics B

MIXED-STATE ENTANGLEMENT IN A SINGLE-COOPER-PAIR BOX DETUNED WITH A COHERENT FIELD

Zhaoxin Li, Yan Xu, LUYIN ZHANG, Da Chen

Published Apr 6, 2011• 0 citations
Publisher

Abstract

A system composed of a single-Cooper-pair box irradiated by a single-mode quantized field has been considered. The entanglement relative to the mixedness μ and the detuning δ is investigated with negative partial transpose. It is found that in the case of initial mixed state, the entanglement is weakened, but increases as time evolves. For a detuned system, the entanglement is further suppressed but more stationary than that for a resonant system.

DOI
10.1142/s021797921110045x

Related papers

QUANTUM DYNAMICS OF A SINGLE COOPER-PAIR BOX WITH A SINGLE-MODE CAVITY FIELD

Meng Zhang, Jian Zou, Bin Shao

We consider a single Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field. We investigate the quantum dynamics of the Cooper-pair box and show that the collapse and revival phenomena can exist in this system, which is sensitive to the detuning between the Josephson energy EJ and cavity field frequency ω.

International Journal of Modern Physics B•Dec 10, 2002•17 citations

Quantum Dynamics and Entropy in a Single-Cooper-Pair Box with a Single-Mode Cavity Field

Meng Zhang, Jian Zou, Bin Shao

We consider a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field. We assume that the box is initially in a mixed state, and investigate the quantum dynamics of the Cooper-pair box and show that the collapse and revival phenomenon can exist in this system. We also study the quantum entropy of the single-Cooper-pair box and discuss the effects of the different parameters on this quantum entropy. We find that the box, which is initially in a mixed state, may evolve into an almost pure state.

International Journal of Modern Physics B•Jun 10, 2003•3 citations

Collapse-Revival and Entanglement in a Single-Cooper-Pair Box with a Single-Mode Cavity Field

张孟, 邹健, 邵彬

A single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field is considered. The degree of entanglement between the quantized field and the single-Cooper-pair box is examined by using the field entropy. It is found that the collapse and revival phenomenon can exist in this system, the entropy reaches its local minimum at one-half of the quiescent period, and the larger the entropy, the greater the entanglement is.

北京理工大学学报：英文版•Jan 1, 2004•0 citations

Collapse-Revival and Entanglement in a Single-Cooper-Pair Box with a Single-Mode Cavity Field

Meng Zhang

A single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field is considered. The degree of entanglement between the quantized field and the single-Cooper-pair box is examined by using the field entropy. It is found that the collapse and revival phenomenon can exist in this system, the entropy reaches its local minimum at one-half of the quiescent period, and the larger the entropy, the greater the entanglement is.

北京理工大学学报：英文版•Jan 1, 2004•0 citations

Entanglement between charge qubit and quantized field

Zhaoxin Li, Zou Jian, Cai Jin-Fang +2 more

We investigate time evolution of the entanglement between charge qubit initially in mixed states and quantized field. By calculating the concurrence lower bound, we study the effect of initial mixedness λ and detuning Δ on the entanglement of the system. In the case of weak field, the degree of entanglement for charge qubit being initially in excited state is much larger than that for charge qubit being initially in ground state, and detuning Δ can efficiently reduce the entanglement. But in the case of strong field, the time evolution of the entanglement is about the same for charge qubit being initially in excited and ground states, the more mixed the initial state of charge qubit is prepared, the weaker the entanglement is, and Δ has less effect on the entanglement than in the case of weak field.

Acta Physica Sinica•Jan 1, 2006•4 citations

Quantum Entropy of a Single Cooper-Pair Box Interacting with Two Electromagnetic Fields

Bin Shao

A Hamiltonian which represents the interaction between a single Cooper-pair box and two quantized electromagnetic fields is considered in order to find new ways for quantum information. The wave function in Schrdinger picture is obtained. The evolution of the entropy of the box as a function of the scaled time is ploted to measure the entanglement between the box and the fields. It is found that the entanglement is sensitive to the detuning between the Josephson energy and the fields frequency, increasing the detuning can decrease the entanglement.

Journal of Beijing Institute of Technology•Jan 1, 2006•0 citations
A system composed of a single-Cooper-pair box irradiated by a single-mode quantized field has been considered. The entanglement relative to the mixedness μ and the detuning δ is investigated with negative partial transpose. It is found that in the case of initial mixed state, the entanglement is weakened, but increases as time evolves. For a detuned system, the entanglement is further suppressed but more stationary than that for a resonant system.
We consider a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field. We assume that the box is initially in a mixed state, and investigate the quantum dynamics of the Cooper-pair box and show that the collapse and revival phenomenon can exist in this system. We also study the quantum entropy of the single-Cooper-pair box and discuss the effects of the different parameters on this quantum entropy. We find that the box, which is initially in a mixed state, may evolve into an almost pure state.
We investigate time evolution of the entanglement between charge qubit initially in mixed states and quantized field. By calculating the concurrence lower bound, we study the effect of initial mixedness λ and detuning Δ on the entanglement of the system. In the case of weak field, the degree of entanglement for charge qubit being initially in excited state is much larger than that for charge qubit being initially in ground state, and detuning Δ can efficiently reduce the entanglement. But in the case of strong field, the time evolution of the entanglement is about the same for charge qubit being initially in excited and ground states, the more mixed the initial state of charge qubit is prepared, the weaker the entanglement is, and Δ has less effect on the entanglement than in the case of weak field.
A Hamiltonian which represents the interaction between a single Cooper-pair box and two quantized electromagnetic fields is considered in order to find new ways for quantum information. The wave function in Schrdinger picture is obtained. The evolution of the entropy of the box as a function of the scaled time is ploted to measure the entanglement between the box and the fields. It is found that the entanglement is sensitive to the detuning between the Josephson energy and the fields frequency, increasing the detuning can decrease the entanglement.