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

Gaussian-state entanglement in a quantum beat laser

Rabia Tahira, Manzoor Ikram, Hyunchul Nha, Muhammad Suhail Zubairy

Published May 23, 2011• 19 citations
Publisher

Abstract

Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. A 77, 062308 (2008)]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.

DOI
10.1103/physreva.83.054304

Related papers

Quantum beat laser as a source of entangled radiation

Shahid Qamar, Fazal Ghafoor, Mark S. Hillery +1 more

We consider a quantum beat laser [Scully and Zubairy, Phys. Rev. A 35 752 (1987)] as a source of entangled radiation. The system essentially consists of three-level atoms inside a doubly resonant cavity such that coherence is introduced by driving the upper two levels with a strong classical field of Rabi frequency $\ensuremath{\Omega}$. We study the dynamics of this system for different values of Rabi frequencies in the presence of cavity losses. It is shown that entanglement can be generated in this system for different initial states of the field in the two modes.

Physical Review A•Jun 5, 2008•80 citations

Generation of two-mode Gaussian-type entangled states of light via a quantum beat laser

Aiping Fang, Yilong Chen, Fuli Li +2 more

The generation of two-mode Gaussian-type entangled states of the cavity field is studied in a quantum beat laser, where three-level atoms of the $V$-type level configuration are coupled to two quantized modes of the cavity field and two upper levels of the atom are driven by a strongly classical field. According to Simon's criterion that is a necessary and sufficient condition for the inseparability of two-mode Gaussian states with a general form of covariance matrices, we analytically and numerically investigate the influence of phase and Rabi frequency of the classical driving field, cavity loss, and the purity and nonclassicality of the initial state of the cavity field on the entanglement property of the resulting two-mode Gaussian state. In the limit of weak cavity loss and strong driving, we show that the cavity field can be periodically into an ideal two-mode entangled Gaussian-type state.

Physical Review A•Jan 25, 2010•33 citations

Entanglement analysis of two-mode Gaussian states in a parametric down-converter

Rabia Tahira, Guo-Qin Ge, Manzoor Ikram

Abstract Parametric down-conversion has been studied as a source of entangled radiation (Lee et al 2008 J. Phys. B: At. Mol. Opt. Phys . 41 145504). We investigate and quantify the entanglement of this system when the initial cavity modes are taken as two-mode Gaussian states. We study the effect of nonclassicality, purity, noise and leakage through the cavity modes on the two-mode Gaussian state entanglement.

Laser Physics Letters•Feb 10, 2017•3 citations

Coherence control of entanglement dynamics of two-mode Gaussian state via Raman driven quantum beat laser using Simon’s criterion

Shakir Ullah, Haleema Sadia Qureshi, Gul Tiaz +2 more

We study the entanglement dynamics of two-mode Gaussian state (TMGS) in a quantum beat laser driven by two classical fields in Raman configuration using Simon's criterion of quantum state separability. The two modes of the cavity field are considered initially in general single-mode Gaussian states. The effect of the non-classicality, purity, and relative phase of the cavity modes on the entanglement phenomenon is studied thoroughly. We show that in the presence of cavity decay rates, the higher the non-classicality of the initial states, the higher is the inseparability of the evolved TMGS of the cavity field. The inseparability, on the other side, is independent of the purity of the initial states. Moreover, the time scale of the entangled state increases with the relative intensity of the driving fields, whereas the relative phase switches the entangled state into the disentangled state of the cavity field and vice versa. The quantum statistics of the mean photons number of the cavity field is analyzed.

Applied Optics•Dec 20, 2018•19 citations

Entanglement of Gaussian states using a beam splitter

Rabia Tahira, Manzoor Ikram, Hyunchul Nha +1 more

We study an experimental scheme to generate Gaussian two-mode entangled states via beam splitter. Specifically, we consider a nonclassical Gaussian state (squeezed state) and a thermal state as two input modes, and evaluate the degree of entanglement at the output. Experimental conditions to generate entangled outputs are completely identified and the critical thermal noise to destroy entanglement is analytically obtained. By doing so, we discuss the possibility to link the resistance to noise in entanglement generation with the degree of single-mode nonclassicality.

arXiv:0810.1399•Physical Review A•Feb 12, 2009•57 citations

Coherence controlled generation of Gaussian quantum discord in a quantum beat laser

Haleema Sadia Qureshi, Shakir Ullah, Fazal Ghafoor

Abstract Quantum discord, an appropriate measure of quantum correlation, is analyzed in a two-mode Gaussian state of the cavity field evolved by a system of quantum beat laser. In the laser system, two arbitrary single-mode Gaussian states of the cavity fields and an external classical field couple to the atomic lasing medium. We calculate the time-dependent expression for the quantum discord both analytically and numerically, by following the reduced density matrix equation of the resulting cavity field. In this framework, we investigate the generation and control of Gaussian quantum discord in the two-mode Gaussian state of the cavity field at the output in terms of the purity and non-classicality of the two input cavity modes, the Rabi frequency of the classical driving field, the relative phase of the coupling parameters, and the damping rates of the cavity modes. The behaviour of quantum discord appears oscillatory due to the quantum beats in the output cavity field developed by the classical driving field in the medium as time passes. Moreover, we find that quantum discord switches on and off while adjusting the relative phase of the coupling parameters. Analysis of the analytical results agrees well with our numerical simulations.

Physica Scripta•Mar 13, 2023•3 citations
Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. A 77, 062308 (2008)]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
We consider a quantum beat laser [Scully and Zubairy, Phys. Rev. A 35 752 (1987)] as a source of entangled radiation. The system essentially consists of three-level atoms inside a doubly resonant cavity such that coherence is introduced by driving the upper two levels with a strong classical field of Rabi frequency $\ensuremath{\Omega}$. We study the dynamics of this system for different values of Rabi frequencies in the presence of cavity losses. It is shown that entanglement can be generated in this system for different initial states of the field in the two modes.
The generation of two-mode Gaussian-type entangled states of the cavity field is studied in a quantum beat laser, where three-level atoms of the VVV-type level configuration are coupled to two quantized modes of the cavity field and two upper levels of the atom are driven by a strongly classical field. According to Simon's criterion that is a necessary and sufficient condition for the inseparability of two-mode Gaussian states with a general form of covariance matrices, we analytically and numerically investigate the influence of phase and Rabi frequency of the classical driving field, cavity loss, and the purity and nonclassicality of the initial state of the cavity field on the entanglement property of the resulting two-mode Gaussian state. In the limit of weak cavity loss and strong driving, we show that the cavity field can be periodically into an ideal two-mode entangled Gaussian-type state.
We study the entanglement dynamics of two-mode Gaussian state (TMGS) in a quantum beat laser driven by two classical fields in Raman configuration using Simon's criterion of quantum state separability. The two modes of the cavity field are considered initially in general single-mode Gaussian states. The effect of the non-classicality, purity, and relative phase of the cavity modes on the entanglement phenomenon is studied thoroughly. We show that in the presence of cavity decay rates, the higher the non-classicality of the initial states, the higher is the inseparability of the evolved TMGS of the cavity field. The inseparability, on the other side, is independent of the purity of the initial states. Moreover, the time scale of the entangled state increases with the relative intensity of the driving fields, whereas the relative phase switches the entangled state into the disentangled state of the cavity field and vice versa. The quantum statistics of the mean photons number of the cavity field is analyzed.
We study an experimental scheme to generate Gaussian two-mode entangled states via beam splitter. Specifically, we consider a nonclassical Gaussian state (squeezed state) and a thermal state as two input modes, and evaluate the degree of entanglement at the output. Experimental conditions to generate entangled outputs are completely identified and the critical thermal noise to destroy entanglement is analytically obtained. By doing so, we discuss the possibility to link the resistance to noise in entanglement generation with the degree of single-mode nonclassicality.
Abstract Quantum discord, an appropriate measure of quantum correlation, is analyzed in a two-mode Gaussian state of the cavity field evolved by a system of quantum beat laser. In the laser system, two arbitrary single-mode Gaussian states of the cavity fields and an external classical field couple to the atomic lasing medium. We calculate the time-dependent expression for the quantum discord both analytically and numerically, by following the reduced density matrix equation of the resulting cavity field. In this framework, we investigate the generation and control of Gaussian quantum discord in the two-mode Gaussian state of the cavity field at the output in terms of the purity and non-classicality of the two input cavity modes, the Rabi frequency of the classical driving field, the relative phase of the coupling parameters, and the damping rates of the cavity modes. The behaviour of quantum discord appears oscillatory due to the quantum beats in the output cavity field developed by the classical driving field in the medium as time passes. Moreover, we find that quantum discord switches on and off while adjusting the relative phase of the coupling parameters. Analysis of the analytical results agrees well with our numerical simulations.