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:2406.13198 · Physical Review A

Single-photon-triggered quantum entanglement between two qubits or at least 2,000 identical qubits

Wangjun Lu, Cuilu Zhai, Tao Hong, Ya‐Ju Song, Ji-Bing Yuan, Lan Xu, Jintao Tan, Shi-Qing Tang

Published Sep 4, 2025• 2 citations
arXivHTMLPDF

Abstract

In this paper, we primarily investigate the generation of quantum entanglement triggered by a single photon between two qubits or multiple qubits and analyze the impact of decoherence of the light field. In the model of single-photon interaction with two qubits, we first study the effect of the initial excited-state weight of the qubits on the entanglement triggered by a single photon. We find that the greater the initial excited-state weight, the smaller the maximum quantum entanglement triggered by the single photon between the two qubits. Specifically, when both qubits are in the excited state, a single photon cannot trigger quantum entanglement between the two qubits. We then examine the impact of the initial coherence of the two qubits on the entanglement triggered by a single photon, and find that a single photon can trigger the maximum quantum entanglement between two qubits when both qubits initially have maximum coherence. In the model of single-photon interaction with multiple qubits, in the limit of a large number of qubits, we find that when the initial excited-state weight of each qubit is larger than the ground-state weight, or when all qubits are initially in the ground state, a single photon cannot trigger quantum entanglement between any two qubits in the multiqubit system. Interestingly, we find that a single photon can trigger quantum entanglement between any two qubits from at least 2000 qubits. Moreover, in this limit, the maximum quantum entanglement between any two qubits in the multiqubit system triggered by a single photon changes with the initial-state parameters and almost no longer depends on the number of qubits. Finally, we discuss the effect of decoherence of the light field, and we find that a higher decoherence strength of the light field weakens the generation of quantum entanglement between qubits in both the single-photon interaction with two qubits and the single-photon interaction with multiple qubits models. However, interestingly, the initial coherence of the qubits can resist the impact of decoherence, especially when the two nonidentical qubits, both having maximum coherence, can maintain the maximum quantum entanglement between the two qubits at 0.5 even as the decoherence strength of the light field increases.

DOI
10.1103/t5mb-lg4t

Related papers

Generation of Entanglement Between Two Noninteracting Qubits via Interaction with Nonclassical Radiation Field

Jian Zou, Cai Jin-Fang, Bin Shao +1 more

We study the interaction between a single-mode quantized field and a quantum system composed of two qubits. We suppose that two qubits initially be prepared in the mixed and separable state, and study how entanglement between two qubits arises in the course of evolution according to the Jaynes–Cummings type interaction with nonclassical radiation field. We also investigate the relation between entanglement and purity of qubit subsystem. We show that different photon statistics have different effects on the dynamical behavior of the qubit subsystem. When the qubits are initially prepared in the maximally mixed and separable state, for coherent state field we cannot find entanglement between two qubits; for squeezed state field entanglement between two qubits exists in several short period of time; for even and odd coherent state fields of large photon number, the dynamical behavior of the entanglement between two qubits shows collapse and revival phenomenon. For odd coherent state field of small photon number, the entanglement with both qubits initially prepared in maximally mixed state can be stronger than that with both qubits initially prepared in pure states. For fields of small photon number, the entanglement strongly depends on the states they are initially prepared in. For coherent state field, and odd and even coherent state fields of large photon number, the entanglement only depends on the purity of the initial state of qubit subsystem. We also show that during the evolution the unentangled state may be purer than the entangled state, and the maximum degree of entanglement may not occur at the time when the qubit subsystem is in the purist state.

Communications in Theoretical Physics•Aug 1, 2005•1 citation

Influence of initial atomic coherence and direct coupling on qubits entanglement in two-qubit Tavis — Cummings model

A. Othman, A. R. Farhutdinova, Eugene K. Bashkirov

The exact dynamics of a model consisting of two identical qubits interacting non-resonantly with the electromagnetic field mode of an ideal resonator via single-photon transitions is found in the presence of direct Ising interaction of qubits. The exact solution is used to calculate the two-qubit negativity of qubits in the case of a coherent initial state of qubits and a thermal state of the resonator field. It is shown that in the case of resonant interaction of qubits with the field, the initial atomic coherence leads to a significant increase in the maximum degree of entanglement. The inclusion of direct Ising interaction of qubits can significantly enhance the entanglement of qubits in both coherent and non-coherent initial states of qubits. In the case of non-resonant interaction of qubits and the resonator field, the detuning leads to a weakening of the effect of atomic coherence on the dynamics of qubit entanglement.

Vestnik of Samara University Natural Science Series•Jun 19, 2025•0 citations

Distributed manipulation of two-qubit entanglement with coupled continuous variables

Li-Tuo Shen, Rongxin Chen, Huai‐Zhi Wu +1 more

We study the dynamics of two qubits separately sent through two coupled resonators, each initially containing a coherent-state field. We present analytical arguments and numerically approximate solutions for the qubit-field system under different two-qubit initial states, photon-hopping strengths, and detunings. In the far off-resonant regime, the maximal entanglement of two qubits can be generated with the initial qubit state in which one qubit is in the excited state and the other is in the ground state, and the initially maximal two-qubit entanglement can be frozen and fully revived even for large mean photon number. When the qubits are both initially in their excited states or ground states, qubit–qubit entanglement birth and death apparently appear in the regime where the photon-hopping strength is close to qubit-field detuning, and its peaks do not decrease monotonically as the interaction time increases. It is interesting to observe that when there is photon hopping between two fields, the field–field entanglement can be larger than 1 and increases as the initial amplitude of the coherent state grows. Our present setup is fundamental for distributed quantum information processing and applicable to different physical qubit-resonator systems.

arXiv:1402.0335•Journal of the Optical Society of America B•Jan 16, 2015•2 citations

Generation of quantum coherence in two-qubit cavity system: qubit-dipole coupling and decoherence effects

A-B A Mohamed, H. A. Hessian, Hichem Eleuch

Abstract The intrinsic decoherence effect for two qubits interacting with a coherent field, under the dipole-dipole interaction and two-photon resonance, is analytically described. We investigate numerically the population inversion and the quantum coherence. The results show that the generated mixture entropy and the entanglement negativity, can be enhanced and protected by the dipole-dipole interaction and by reducing the initial coherent field intensity. In particular, we find that, the collapses and revivals of the population inversion present high sensitivity to these physical parameters. The nonlinearity of the two-photon processes leads to a generation of a strong two-qubit entanglement. This generated entanglement depends on the initial coherent field intensity, the dipole-dipole interaction and the intrinsic decoherence.

Physica Scripta•May 1, 2020•12 citations

Quantum coherence induced by a flux qubit coupled by a resonator coherent field through a two-photon interaction

A-B A Mohamed, H. A. Hessian, Fuad S. Alduais +1 more

Abstract The intrinsic decoherence effects on a flux qubit coupled to a resonator through a two-photon interaction where the resonator field is initially in coherent and even coherent states are investigated. The qubit-resonator entanglement and coherence loss (mixedness) of the system and its subsystems are examined using entropy and negativity. The ability of the qubit-resonator interaction to generate quantum coherence (qubit-resonator entanglement and mixedness) is shown to be dependent on the initial cavity non-classicality, detuning, and decoherence. For larger values of the qubit-resonator detuning, the initial resonator non-classicality can enhance the generation and stability of quantum coherence. The decoherence degrades the qubit-resonator entanglement and destroys the sudden death-birth entanglement.

Physica Scripta•Dec 1, 2021•5 citations

Entanglement between two qubits one of which interacts with a thermal field

Eugene K. Bashkirov, Michail S. Mastyugin

In this paper, we have investigated the entanglement between two dipole coupled two-level atoms. The model, in which only one atom is trapped in an lossless cavity and interacts with single-mode thermal field, and the other one can be spatially moved freely outside the cavity has been carried out. We have considered the effect of the atomic coherence on the entanglement behavior. We have shown that a thermal field might cause high entanglement between the atoms both for coherent and incoherent initial atomic states only for small values of the cavity mean photon number. In the considered model the atoms would get entangled even when both atoms are initially in the excited state. We have also derived that the degree of entanglement is weakly dependent on the strength of dipole-dipole interaction for coherent initial states.

arXiv:1505.04287•May 16, 2015•0 citations
In this paper, we primarily investigate the generation of quantum entanglement triggered by a single photon between two qubits or multiple qubits and analyze the impact of decoherence of the light field. In the model of single-photon interaction with two qubits, we first study the effect of the initial excited-state weight of the qubits on the entanglement triggered by a single photon. We find that the greater the initial excited-state weight, the smaller the maximum quantum entanglement triggered by the single photon between the two qubits. Specifically, when both qubits are in the excited state, a single photon cannot trigger quantum entanglement between the two qubits. We then examine the impact of the initial coherence of the two qubits on the entanglement triggered by a single photon, and find that a single photon can trigger the maximum quantum entanglement between two qubits when both qubits initially have maximum coherence. In the model of single-photon interaction with multiple qubits, in the limit of a large number of qubits, we find that when the initial excited-state weight of each qubit is larger than the ground-state weight, or when all qubits are initially in the ground state, a single photon cannot trigger quantum entanglement between any two qubits in the multiqubit system. Interestingly, we find that a single photon can trigger quantum entanglement between any two qubits from at least 2000 qubits. Moreover, in this limit, the maximum quantum entanglement between any two qubits in the multiqubit system triggered by a single photon changes with the initial-state parameters and almost no longer depends on the number of qubits. Finally, we discuss the effect of decoherence of the light field, and we find that a higher decoherence strength of the light field weakens the generation of quantum entanglement between qubits in both the single-photon interaction with two qubits and the single-photon interaction with multiple qubits models. However, interestingly, the initial coherence of the qubits can resist the impact of decoherence, especially when the two nonidentical qubits, both having maximum coherence, can maintain the maximum quantum entanglement between the two qubits at 0.5 even as the decoherence strength of the light field increases.
We study the interaction between a single-mode quantized field and a quantum system composed of two qubits. We suppose that two qubits initially be prepared in the mixed and separable state, and study how entanglement between two qubits arises in the course of evolution according to the Jaynes–Cummings type interaction with nonclassical radiation field. We also investigate the relation between entanglement and purity of qubit subsystem. We show that different photon statistics have different effects on the dynamical behavior of the qubit subsystem. When the qubits are initially prepared in the maximally mixed and separable state, for coherent state field we cannot find entanglement between two qubits; for squeezed state field entanglement between two qubits exists in several short period of time; for even and odd coherent state fields of large photon number, the dynamical behavior of the entanglement between two qubits shows collapse and revival phenomenon. For odd coherent state field of small photon number, the entanglement with both qubits initially prepared in maximally mixed state can be stronger than that with both qubits initially prepared in pure states. For fields of small photon number, the entanglement strongly depends on the states they are initially prepared in. For coherent state field, and odd and even coherent state fields of large photon number, the entanglement only depends on the purity of the initial state of qubit subsystem. We also show that during the evolution the unentangled state may be purer than the entangled state, and the maximum degree of entanglement may not occur at the time when the qubit subsystem is in the purist state.
The exact dynamics of a model consisting of two identical qubits interacting non-resonantly with the electromagnetic field mode of an ideal resonator via single-photon transitions is found in the presence of direct Ising interaction of qubits. The exact solution is used to calculate the two-qubit negativity of qubits in the case of a coherent initial state of qubits and a thermal state of the resonator field. It is shown that in the case of resonant interaction of qubits with the field, the initial atomic coherence leads to a significant increase in the maximum degree of entanglement. The inclusion of direct Ising interaction of qubits can significantly enhance the entanglement of qubits in both coherent and non-coherent initial states of qubits. In the case of non-resonant interaction of qubits and the resonator field, the detuning leads to a weakening of the effect of atomic coherence on the dynamics of qubit entanglement.
We study the dynamics of two qubits separately sent through two coupled resonators, each initially containing a coherent-state field. We present analytical arguments and numerically approximate solutions for the qubit-field system under different two-qubit initial states, photon-hopping strengths, and detunings. In the far off-resonant regime, the maximal entanglement of two qubits can be generated with the initial qubit state in which one qubit is in the excited state and the other is in the ground state, and the initially maximal two-qubit entanglement can be frozen and fully revived even for large mean photon number. When the qubits are both initially in their excited states or ground states, qubit–qubit entanglement birth and death apparently appear in the regime where the photon-hopping strength is close to qubit-field detuning, and its peaks do not decrease monotonically as the interaction time increases. It is interesting to observe that when there is photon hopping between two fields, the field–field entanglement can be larger than 1 and increases as the initial amplitude of the coherent state grows. Our present setup is fundamental for distributed quantum information processing and applicable to different physical qubit-resonator systems.
Abstract The intrinsic decoherence effect for two qubits interacting with a coherent field, under the dipole-dipole interaction and two-photon resonance, is analytically described. We investigate numerically the population inversion and the quantum coherence. The results show that the generated mixture entropy and the entanglement negativity, can be enhanced and protected by the dipole-dipole interaction and by reducing the initial coherent field intensity. In particular, we find that, the collapses and revivals of the population inversion present high sensitivity to these physical parameters. The nonlinearity of the two-photon processes leads to a generation of a strong two-qubit entanglement. This generated entanglement depends on the initial coherent field intensity, the dipole-dipole interaction and the intrinsic decoherence.
Abstract The intrinsic decoherence effects on a flux qubit coupled to a resonator through a two-photon interaction where the resonator field is initially in coherent and even coherent states are investigated. The qubit-resonator entanglement and coherence loss (mixedness) of the system and its subsystems are examined using entropy and negativity. The ability of the qubit-resonator interaction to generate quantum coherence (qubit-resonator entanglement and mixedness) is shown to be dependent on the initial cavity non-classicality, detuning, and decoherence. For larger values of the qubit-resonator detuning, the initial resonator non-classicality can enhance the generation and stability of quantum coherence. The decoherence degrades the qubit-resonator entanglement and destroys the sudden death-birth entanglement.
In this paper, we have investigated the entanglement between two dipole coupled two-level atoms. The model, in which only one atom is trapped in an lossless cavity and interacts with single-mode thermal field, and the other one can be spatially moved freely outside the cavity has been carried out. We have considered the effect of the atomic coherence on the entanglement behavior. We have shown that a thermal field might cause high entanglement between the atoms both for coherent and incoherent initial atomic states only for small values of the cavity mean photon number. In the considered model the atoms would get entangled even when both atoms are initially in the excited state. We have also derived that the degree of entanglement is weakly dependent on the strength of dipole-dipole interaction for coherent initial states.