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

Physical Review A

Entanglement detection in a coupled atom-field system via quantum Fisher information

Safoura Sadat Mirkhalaf, Augusto Smerzi

Published Feb 2, 2017• 16 citations
Publisher

Abstract

We consider a system of finite number of particles collectively interacting with a single-mode coherent field inside a cavity. Depending on the strength of the initial field compared to the number of atoms, we consider three regimes of weak-, intermediate-, and strong-field interaction. The dynamics of multiparticle entanglement detected by quantum Fisher information and spin squeezing are studied in each regime. It is seen that in the weak-field regime, spin squeezing and quantum Fisher information coincide. However, by increasing the initial field population toward the strong-field regime, quantum Fisher information is more effective in detecting entanglement compared to spin squeezing. In addition, in the two-atom system, we also study concurrence. In this case, the quantum Fisher information as a function of time is in good agreement with concurrence in predicting entanglement peaks.

DOI
10.1103/physreva.95.022302

Related papers

Entanglement detection via quantum Fisher information in a coupled atom-field system

Safoura Sadat Mirkhalaf

We consider a system of finite number of particles collectively interacting with a single mode coherent \nfield inside the cavity. Depending on the strength of the initial field compared to the number of \natoms, we introduce three regimes of weak, intermediate and strong field interaction. The dynamics \nof multi-particle entanglement detected by quantum Fisher information is studied in each regime. \nSpecifically, for the two extreme limits of weak and strong field regimes, analytical results are \nfound. Moreover, we have compared our outcomes with spin squeezing. It is seen that in the weak \nfield regime, spin squeezing and quantum Fisher information coincides. However, by increasing the \ninitial field population toward the strong field regime, spin squeezing compared to quantum Fisher \ninformation gradually decreases and eventually fails in detecting entanglement. In addition, in the \ntwo-atom system, we also consider concurrence. In this case, the quantum Fisher information and \nconcurrence show good agreement in predicting entanglement peaks.

•Jan 1, 2016•0 citations

Response of quantum Fisher information, variance entropy squeezing and entanglement to the intrinsic decoherence of two non-degenerate fields interacting with two qubits

S. Abdel‐Khalek, Eied Mahmoud Khalil, A.‐B. A. Mohamed +2 more

We investigate the link between quantum Fisher information (QFI) and quantum entanglement for a scheme of two atoms that interact with two non-degenerate modes in the absence and presence of intrinsic decoherence effect. The explicit form of the density matrix approach to the dissipative systems is given when the cavity-field is in generalized coherent states. The dynamical behavior of the QFI is compared with the atom–atom concurrence entanglement. We examine the effect of the dipole–dipole interaction and intrinsic decoherence on the dynamical properties of the QFI, concurrence and variance entropy squeezing. It is found that the atom–atom concurrence and the QFI can be controlled by the intrinsic decoherence and the dipole–dipole interaction.

Alexandria Engineering Journal•Oct 23, 2020•5 citations

Quantum scheme of dissipative two qubits in a squeezed field: Entanglement and Fisher information

S. Abdel‐Khalek, Eied Mahmoud Khalil, Hammad Alotaibi +3 more

A clear relationship between the quantum version of Fisher information and the bipartite system entanglement has been explored recently. Known existing results for some quantum systems having strongly nonlocal correlations are still limited. In this paper, based on the interaction between a two-qubit and squeezed field, we investigate the correlation between the dynamical behavior of qubit-qubit entanglement and the quantum Fisher information (QFI). We focus on the effect of a number of photon multiplicity, low and high squeezing regime of the field on the dynamics of the QFI and entanglement quantifier. We show how the QFI and entanglement quantifier can be affected by the number of photon multiplicity and squeeze parameter during the time evolution of cases of absence and presence of dissipation effect. Our results exhibit the correlation between the entanglement quantifiers and the QFI with respect to the appearance of collapse and revival phenomena of the atomic inversion.

Alexandria Engineering Journal•Feb 21, 2021•3 citations

Atomic entanglement and decoherence.

Claudiu Genes

The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new unravelling is proposed, that employs the detection of photon number in a single output channel and is capable of producing mesoscopic Schrodinger cat states in a single step. As a first step to understanding the role of cooperative decoherence, of importance in the case of dense pencil-shaped atomic ensembles, the collective spin decoherence of a two multilevel atom system is derived. This calculation is also relevant to entanglement loss for two qubits manipulated using with reading/writing pulses. Finally, a scheme is proposed in which arbitrarily strong entanglement can be produced in a four-wave mixing setup, where the preparation of the atoms in a dark state limits the decoherence to negligible values.

•Jan 1, 2006•0 citations

Entanglement and atomic Fisher information of a two qubits and optical field in squeezed thermal state

Mariam Algarni, Hanan Al–Ghamdi, S. Abdel‐Khalek

Quantum information technology depends on an invaluable and tenuous resource, named quantum correlation, that shows strong significant manifestation of the coherent overlap of states of a combined quantum systems. So the quantifier of this resource under factual conditions that is, whereas corrupted via generalized optical radiation field states is still limited, and common statements on entanglement dynamics. In this article, we describe quantitatively the nonlocal correlation between a two-qubit and squeezed thermal field. Especially, considering the effect thermal photons and number of photons transition between the two qubits and squeezed thermal field. Also, the Mandel parameter, entanglement and atomic Fisher information over the time evolution as a function of implicated parameters in the system are investigated. We have shown that the squeeze parameter and thermal photons have a potential effect of the dynamical properties of the atomic Fisher information, Mandel parameter and entanglement. Also, the AFI is very sensitive to the field parameters rather than the number of photons transition. Furthermore, the results interpreted in the case of thermal environment considering the effect of thermal photons and squeeze parameter on the evolution of the system under consideration.

Journal of Intelligent & Fuzzy Systems•Nov 28, 2019•1 citation

Dynamics of atom-field entanglement: Towards strong-coupling and non-Markovian regimes

Nick Cummings, B. L. Hu

We examine the dynamics of bipartite quantum entanglement between a two-level atom and the electromagnetic field. We begin with the Jaynes-Cummings model with a single field mode and examine in detail the exact time evolution of entanglement, including cases where the atomic state is initially mixed and the atomic transition is detuned from resonance. We then explore the effects of other nearby modes by calculating the exact time evolution of entanglement in more complex systems with two, three, and five field modes. For these cases we can obtain exact solutions which include the strong-coupling regime. Finally, we consider the entanglement of a two-level atom with the infinite collection of modes present in the intracavity field of a Fabre-Perot cavity. In contrast to the usual treatment of atom-field interactions with a continuum of modes using the Born-Markov approximation, our treatment in all cases describes the full non-Markovian dynamics of the atomic subsystem under general couplings. Only when an analytic expression for the infinite mode case is desired do we need to make a weak coupling assumption which at late times approximates Markovian dynamics.

arXiv:0708.2257•Physical Review A•May 30, 2008•17 citations
We consider a system of finite number of particles collectively interacting with a single-mode coherent field inside a cavity. Depending on the strength of the initial field compared to the number of atoms, we consider three regimes of weak-, intermediate-, and strong-field interaction. The dynamics of multiparticle entanglement detected by quantum Fisher information and spin squeezing are studied in each regime. It is seen that in the weak-field regime, spin squeezing and quantum Fisher information coincide. However, by increasing the initial field population toward the strong-field regime, quantum Fisher information is more effective in detecting entanglement compared to spin squeezing. In addition, in the two-atom system, we also study concurrence. In this case, the quantum Fisher information as a function of time is in good agreement with concurrence in predicting entanglement peaks.
We consider a system of finite number of particles collectively interacting with a single mode coherent \nfield inside the cavity. Depending on the strength of the initial field compared to the number of \natoms, we introduce three regimes of weak, intermediate and strong field interaction. The dynamics \nof multi-particle entanglement detected by quantum Fisher information is studied in each regime. \nSpecifically, for the two extreme limits of weak and strong field regimes, analytical results are \nfound. Moreover, we have compared our outcomes with spin squeezing. It is seen that in the weak \nfield regime, spin squeezing and quantum Fisher information coincides. However, by increasing the \ninitial field population toward the strong field regime, spin squeezing compared to quantum Fisher \ninformation gradually decreases and eventually fails in detecting entanglement. In addition, in the \ntwo-atom system, we also consider concurrence. In this case, the quantum Fisher information and \nconcurrence show good agreement in predicting entanglement peaks.
We investigate the link between quantum Fisher information (QFI) and quantum entanglement for a scheme of two atoms that interact with two non-degenerate modes in the absence and presence of intrinsic decoherence effect. The explicit form of the density matrix approach to the dissipative systems is given when the cavity-field is in generalized coherent states. The dynamical behavior of the QFI is compared with the atom–atom concurrence entanglement. We examine the effect of the dipole–dipole interaction and intrinsic decoherence on the dynamical properties of the QFI, concurrence and variance entropy squeezing. It is found that the atom–atom concurrence and the QFI can be controlled by the intrinsic decoherence and the dipole–dipole interaction.
A clear relationship between the quantum version of Fisher information and the bipartite system entanglement has been explored recently. Known existing results for some quantum systems having strongly nonlocal correlations are still limited. In this paper, based on the interaction between a two-qubit and squeezed field, we investigate the correlation between the dynamical behavior of qubit-qubit entanglement and the quantum Fisher information (QFI). We focus on the effect of a number of photon multiplicity, low and high squeezing regime of the field on the dynamics of the QFI and entanglement quantifier. We show how the QFI and entanglement quantifier can be affected by the number of photon multiplicity and squeeze parameter during the time evolution of cases of absence and presence of dissipation effect. Our results exhibit the correlation between the entanglement quantifiers and the QFI with respect to the appearance of collapse and revival phenomena of the atomic inversion.
The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new unravelling is proposed, that employs the detection of photon number in a single output channel and is capable of producing mesoscopic Schrodinger cat states in a single step. As a first step to understanding the role of cooperative decoherence, of importance in the case of dense pencil-shaped atomic ensembles, the collective spin decoherence of a two multilevel atom system is derived. This calculation is also relevant to entanglement loss for two qubits manipulated using with reading/writing pulses. Finally, a scheme is proposed in which arbitrarily strong entanglement can be produced in a four-wave mixing setup, where the preparation of the atoms in a dark state limits the decoherence to negligible values.
Quantum information technology depends on an invaluable and tenuous resource, named quantum correlation, that shows strong significant manifestation of the coherent overlap of states of a combined quantum systems. So the quantifier of this resource under factual conditions that is, whereas corrupted via generalized optical radiation field states is still limited, and common statements on entanglement dynamics. In this article, we describe quantitatively the nonlocal correlation between a two-qubit and squeezed thermal field. Especially, considering the effect thermal photons and number of photons transition between the two qubits and squeezed thermal field. Also, the Mandel parameter, entanglement and atomic Fisher information over the time evolution as a function of implicated parameters in the system are investigated. We have shown that the squeeze parameter and thermal photons have a potential effect of the dynamical properties of the atomic Fisher information, Mandel parameter and entanglement. Also, the AFI is very sensitive to the field parameters rather than the number of photons transition. Furthermore, the results interpreted in the case of thermal environment considering the effect of thermal photons and squeeze parameter on the evolution of the system under consideration.
We examine the dynamics of bipartite quantum entanglement between a two-level atom and the electromagnetic field. We begin with the Jaynes-Cummings model with a single field mode and examine in detail the exact time evolution of entanglement, including cases where the atomic state is initially mixed and the atomic transition is detuned from resonance. We then explore the effects of other nearby modes by calculating the exact time evolution of entanglement in more complex systems with two, three, and five field modes. For these cases we can obtain exact solutions which include the strong-coupling regime. Finally, we consider the entanglement of a two-level atom with the infinite collection of modes present in the intracavity field of a Fabre-Perot cavity. In contrast to the usual treatment of atom-field interactions with a continuum of modes using the Born-Markov approximation, our treatment in all cases describes the full non-Markovian dynamics of the atomic subsystem under general couplings. Only when an analytic expression for the infinite mode case is desired do we need to make a weak coupling assumption which at late times approximates Markovian dynamics.