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

Optical and Quantum Electronics

Enhancing entanglement and non-Markovianity in an optomechanical system via atom quasi-random walk motion

Mahmoud Mohammadi, Safa Jami, Mehdi Khazaei Nezhad

Published Dec 27, 2023• 2 citations
Publisher

Abstract

Abstract Optomechanical cavities are one of the most important systems for observing quantum phenomena. In this paper, we investigated the quantum aspect of an optomechanical system made up of a two-level atom under two laser pump stimulation. One of the laser pumps drives the optical cavity, known as a longitudinal pump, while the second laser was used to excite the atom inside the cavity, directly and called as transverse pump. We observe the quasi-random walk of atom inside the cavity. Next, entanglement evolution among the atomic states and the other parts of the system with the von Neumann entropy measure was investigated. The study was done for distinctive atomic states in a strong coupling regime between the atom and field of cavity. Also, we investigated the evidence for non-Markovian behavior with trace distance measure. Our results demonstrate that the random walk of the atom can offer assistance to us to upgrade the entanglement between the inside atom mode and the other parts of the system for a long time. Furthermore, adding atomic motion provides evidence for the non-Markovian treatment of the system at the initial time.

DOI
10.1007/s11082-023-05707-7

Related papers

Nonclassical effects in optomechanics: dynamics and collapse of entanglement

Pradip Laha, S. Lakshmibala, V. Balakrishnan

We have investigated a wide range of nonclassical behavior exhibited by a tripartite cavity optomechanical system comprising a two-level atom placed inside a Fabry–Perot type optical cavity with a vibrating mirror attached to one end. We have shown that the atom’s subsystem von Neumann entropy collapses to its maximum allowed value over a significant time interval during dynamical evolution. This feature is sensitive to the nature of the initial state, the specific form of intensity-dependent tripartite coupling, and system parameters. The extent of nonclassicality of the field is assessed through the Mandel Q parameter and Wigner function. Both entropic and quadrature squeezing properties of the field are quantified directly from optical tomograms, thereby avoiding tedious state reconstruction procedures.

arXiv:1808.04984•Journal of the Optical Society of America B•Feb 7, 2019•10 citations

Witnessing entanglement between two two-level atoms moving inside a leaky cavity under classical control

J. Taghipour, B. Mojaveri, Alireza Dehghani

Based on the quantum memory-assisted entropic uncertainty relation (QMA-EUR), we investigate the Markovian and non-Markovian dynamics of entanglement witness in a two-atom system that asymmetrically are coupled to a leaky cavity with two-photon relaxation. The atoms are two-level systems, they move inside the cavity and interact with a classical driving laser field. We discuss in detail the effects of the translational movement of the atoms, classical driving field and atom-cavity coupling on the protection of entanglement witness. Our results show that with a regular increase in the intensity of the classical driving field, the entanglement region witnessed by lower bound of QMA-EUR increases and the time of entanglement witness gets longer. In the Markovian regime, we find that quantum entanglement between the moving atoms can be witnessed for a longer time by increasing the velocity of the atoms. However, in the non-Markovian regime, higher speeds are required to witness entanglement over long time intervals. In addition, we conclude that the entanglement region witnessed by the lower bound of QMA-EUR can be protected in both the symmetrical and asymmetrical atom-cavity coupling regimes. In the asymmetrical regime, a better protection can be achieved when the memory atom is coupled to the cavity field stronger than the other atom.

Modern Physics Letters A•Jul 20, 2022•9 citations

Preservation Macroscopic Entanglement of Optomechanical Systems in non-Markovian Environment

Jiong Cheng, Wen-Zhao Zhang, Ling Zhou +1 more

We investigate dynamics of an optomechanical system under the non-Markovian environment. In the weak optomechanical single-photon coupling regime, we provide an analytical approach fully taking into account the non-Markovian memory effects. When the cavity-bath coupling strength crosses a certain threshold, an oscillating memory state for the classical cavity field is formed. Due to the existence of the non-decay optical bound state, a nonequilibrium optomechanical thermal entanglement is preserved even without external driving laser. Our results provide a potential usage to generate and protect entanglement via non-Markovian environment.

arXiv:1511.01267•Scientific Reports•Apr 1, 2016•43 citations

Dynamics of an atomic system associated with a cavity-optomechanical system

Maged Faihan Alotaibi, Eied Mahmoud Khalil, Mahmoud Youssef Abd‐Rabbou

This paper introduces the effective Hamiltonian of two two-level atoms inside a cavity with a movable mirror. The temporal evolution of the output density state that includes the interaction between movable mirror, atoms, and field is obtained. The dynamical properties of the quantum correlations of the system are studied via l1-norm of coherence, Entanglement of Formation (EoF) and Bell non-locality. The results shown that the phenomena of coherence, and non-locality are approached to the degree of entanglement as the initial atomic state is set in an excited state. However, different chaotic behavior is generated for the coherence at the initially mixed state. Overall, the temporal evolution of entanglement is an intermediate correlation that lies in between coherence and normalized Bell non-locality.

Results in Physics•Apr 27, 2022•22 citations

Entanglement and coherence in a hybrid Laguerre–Gaussian rotating cavity optomechanical system with two-level atoms

S. K. Singh, Jia‐Xin Peng, Muhammad Asjad +1 more

Abstract We theoretically investigate quantum entanglement and coherence in a hybrid Laguerre–Gaussian rotating cavity optomechanical system with two-level atoms, where cavity and mechanical modes are coupled through the exchange of orbital angular momentum. Our study shows that the injection of atoms with a suitable choice of the physical parameters can significantly improve the degree of optomechanical entanglement in all aspects. In the study of quantum coherence research, we show more comprehensively the negative and positive effects of atoms on the coherence. The result obtained is that only when the atom is significantly off-resonant to driving field, the coupling strength in between the atoms and light field increases and the quantum coherence can be enhanced, otherwise it will reduce quantum coherence. In addition, the atomic decay suppresses quantum coherence phenomenon.

Journal of Physics B Atomic Molecular and Optical Physics•Nov 3, 2021•66 citations

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
Abstract Optomechanical cavities are one of the most important systems for observing quantum phenomena. In this paper, we investigated the quantum aspect of an optomechanical system made up of a two-level atom under two laser pump stimulation. One of the laser pumps drives the optical cavity, known as a longitudinal pump, while the second laser was used to excite the atom inside the cavity, directly and called as transverse pump. We observe the quasi-random walk of atom inside the cavity. Next, entanglement evolution among the atomic states and the other parts of the system with the von Neumann entropy measure was investigated. The study was done for distinctive atomic states in a strong coupling regime between the atom and field of cavity. Also, we investigated the evidence for non-Markovian behavior with trace distance measure. Our results demonstrate that the random walk of the atom can offer assistance to us to upgrade the entanglement between the inside atom mode and the other parts of the system for a long time. Furthermore, adding atomic motion provides evidence for the non-Markovian treatment of the system at the initial time.
We have investigated a wide range of nonclassical behavior exhibited by a tripartite cavity optomechanical system comprising a two-level atom placed inside a Fabry–Perot type optical cavity with a vibrating mirror attached to one end. We have shown that the atom’s subsystem von Neumann entropy collapses to its maximum allowed value over a significant time interval during dynamical evolution. This feature is sensitive to the nature of the initial state, the specific form of intensity-dependent tripartite coupling, and system parameters. The extent of nonclassicality of the field is assessed through the Mandel Q parameter and Wigner function. Both entropic and quadrature squeezing properties of the field are quantified directly from optical tomograms, thereby avoiding tedious state reconstruction procedures.
Based on the quantum memory-assisted entropic uncertainty relation (QMA-EUR), we investigate the Markovian and non-Markovian dynamics of entanglement witness in a two-atom system that asymmetrically are coupled to a leaky cavity with two-photon relaxation. The atoms are two-level systems, they move inside the cavity and interact with a classical driving laser field. We discuss in detail the effects of the translational movement of the atoms, classical driving field and atom-cavity coupling on the protection of entanglement witness. Our results show that with a regular increase in the intensity of the classical driving field, the entanglement region witnessed by lower bound of QMA-EUR increases and the time of entanglement witness gets longer. In the Markovian regime, we find that quantum entanglement between the moving atoms can be witnessed for a longer time by increasing the velocity of the atoms. However, in the non-Markovian regime, higher speeds are required to witness entanglement over long time intervals. In addition, we conclude that the entanglement region witnessed by the lower bound of QMA-EUR can be protected in both the symmetrical and asymmetrical atom-cavity coupling regimes. In the asymmetrical regime, a better protection can be achieved when the memory atom is coupled to the cavity field stronger than the other atom.
We investigate dynamics of an optomechanical system under the non-Markovian environment. In the weak optomechanical single-photon coupling regime, we provide an analytical approach fully taking into account the non-Markovian memory effects. When the cavity-bath coupling strength crosses a certain threshold, an oscillating memory state for the classical cavity field is formed. Due to the existence of the non-decay optical bound state, a nonequilibrium optomechanical thermal entanglement is preserved even without external driving laser. Our results provide a potential usage to generate and protect entanglement via non-Markovian environment.
This paper introduces the effective Hamiltonian of two two-level atoms inside a cavity with a movable mirror. The temporal evolution of the output density state that includes the interaction between movable mirror, atoms, and field is obtained. The dynamical properties of the quantum correlations of the system are studied via l1-norm of coherence, Entanglement of Formation (EoF) and Bell non-locality. The results shown that the phenomena of coherence, and non-locality are approached to the degree of entanglement as the initial atomic state is set in an excited state. However, different chaotic behavior is generated for the coherence at the initially mixed state. Overall, the temporal evolution of entanglement is an intermediate correlation that lies in between coherence and normalized Bell non-locality.
Abstract We theoretically investigate quantum entanglement and coherence in a hybrid Laguerre–Gaussian rotating cavity optomechanical system with two-level atoms, where cavity and mechanical modes are coupled through the exchange of orbital angular momentum. Our study shows that the injection of atoms with a suitable choice of the physical parameters can significantly improve the degree of optomechanical entanglement in all aspects. In the study of quantum coherence research, we show more comprehensively the negative and positive effects of atoms on the coherence. The result obtained is that only when the atom is significantly off-resonant to driving field, the coupling strength in between the atoms and light field increases and the quantum coherence can be enhanced, otherwise it will reduce quantum coherence. In addition, the atomic decay suppresses quantum coherence phenomenon.
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.