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

Journal of Physics B Atomic Molecular and Optical Physics

Continuous variable entanglement in a coherently pumped correlated emission laser

Sintayehu Tesfa

Published Feb 26, 2008• 25 citations
Publisher

Abstract

Analysis of the effects of external pumping on the quantum features of cavity radiation of the two-photon correlated emission laser is presented. It turns out that the pumping process induces the atomic coherence responsible for the entanglement of the cavity radiation as well as the correlation between the photon numbers belonging to different modes, despite the arising vacuum fluctuations. The photon number correlation is found to be very close to 2 where the entanglement is relatively better. Moreover, the mean number of photon pairs decreases with the amplitude of the driving radiation which is one of the practical limitations associated with the pumping mechanism. It is also shown that the mean photon number of the radiation in mode b is less than one-third of that in mode a.

DOI
10.1088/0953-4075/41/5/055503

Related papers

Externally induced continuous variable entanglement in a correlated emission laser

Sintayehu Tesfa

Analysis of the externally induced quantum features of the cavity radiation of the two-photon correlated emission laser is presented. It turns out that the pumping process induces atomic coherence accountable for observing entanglement in the cavity radiation as well as the nonclassical photon number correlation despite the arising vacuum fluctuations. Even though a significant continuous variable entanglement is obtained near threshold in the strong driving limit, increasing the amplitude of the driving radiation more than required for a fixed value of the linear gain coefficient is found to degrade the degree of entanglement. The two-mode squeezing of the superimposed radiation, entanglement of the cavity radiation and mean number of photon pairs increase with the rate at which the atoms are injected into the cavity, but the nonclassical photon number correlation decreases. Moreover, the mean photon number corresponding to the transition from the upper energy level to the intermediate is found to be greater than the transition from the intermediate to the lower. With conceivable practical challenges, it is in principle possible to generate an intense continuous variable entanglement and quantify it via photon count measurements.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 30, 2008•24 citations

Effect of dephasing on quantum features of the cavity radiation of an externally pumped correlated emission laser

Sintayehu Tesfa

Analysis of the effects of dephasing on quantum features of the cavity radiation of externally pumped correlated emission laser is presented. It turns out that entanglement and nonclassical photon number correlations are strongly reliant on the rate at which the atomic coherent superposition decays specially when the amplitude of the driving radiation is smaller. It is, particularly, found that almost perfectly entangled light can be generated while the rate of dephasing and the amplitude of the external driving radiation are kept low in case the atoms are initially prepared in possible maximum coherence. It is also found that the nonclassical behavior of the photon correlation associated with the violation of Cauchy-Schwarz inequality decreases with the rate of dephasing except for some values of the amplitude of the driving radiation.

Physical Review A•Jun 10, 2009•21 citations

Role of externally induced coherent superposition in demonstrating quantum nonlocality in a correlated emission laser

Sintayehu Tesfa

Analysis of the effects of external pumping on the quantum features, including entanglement, quantum nonlocality and nonclassical photon number correlations, of the cavity radiation of a correlated emission laser is presented. It turns out that the contribution of externally induced coherent superposition in demonstrating quantum nonlocality is significant. Despite the available evidence that entangled states can exhibit nonlocality for certain values of the rate at which the atoms are injected into the cavity and amplitude of the driving radiation, a direct relation between the degree of entanglement and quantum nonlocality cannot be established. However, it seems likely to make a consistent connection between the Cauchy–Schwarz and Bell–Clauser–Horne–Shimony–Holt inequalities. It is evident that comparison among various nonclassical correlations enhances the understanding of the otherwise intricate quantum theoretical predictions.

Journal of Physics B Atomic Molecular and Optical Physics•Dec 3, 2008•3 citations

Effects of decoherence on entanglement in a correlated emission laser

Sintayehu Tesfa

We present the analysis of the effects of decoherence on quantum features of the cavity radiation of the two-photon-correlated emission laser, employing the stochastic differential equations associated with the normal ordering. We study how a thermal noise entering the cavity affects the squeezing, entanglement amplification, mean number of photon pairs and intensity difference in the cavity radiation. It turns out that the generated light exhibits a two-mode squeezing and entanglement when initially there are more atoms at the lower level, even when the cavity is coupled to a thermal reservoir. It is also found that though the thermal noise entering the cavity degrades the squeezing and entanglement, it significantly increases the mean number of photon pairs of the superimposed radiation.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 5, 2007•38 citations

Dependence of the evolution of the cavity radiation of a coherently pumped correlated emission laser on dephasing and phase fluctuation

Sintayehu Tesfa

A detailed analysis of the dynamics of the cavity radiation of a coherently pumped correlated emission laser is presented. The phase fluctuation and dephasing are found to affect the time evolution of the two-mode squeezing and intensity significantly. The intensity and degree of the two-mode squeezing increase at early stages of the process with time, but this trend changes rapidly afterwards. It is also shown that they increase with phase fluctuation and dephasing in the strong driving limit; however, the situation appears to be opposite in the weak driving limit. This essentially suggests that the phase fluctuation and dephasing weaken the coherence induced by a strong driving mechanism so that the spontaneous emission gets a chance. Moreover, the degree of two-mode squeezing turns out to increase with the rate of injection of the atoms into the cavity only at early stages, whereas the mean photon number increases throughout the lasing process. The other important aspect of the phase fluctuation, in this regard, is the relaxation of the time at which the maximum squeezing is manifested as well as the time in which the radiation remains in a squeezed state.

arXiv:1011.3673•Physical Review A•Feb 14, 2011•13 citations

A Bright Entanglement and Squeezing Generated by an External Pumping Radiation in a Correlated Emission Laser

Chimdessa Gashu Feyisa

The quantum and statistical properties of light generated by an external classical field in a correlated emission laser with a parametric amplifier and coupled to a squeezed vacuum reservoir are investigated using the combination of the master and stochastic differential equations. First, the solutions of the cavity-mode variables and correlation properties of noise forces associated to the normal ordering are obtained. Next, applying the resulting solutions, the mean photon number of the separate cavity modes and their crosscorrelation, smallest eigenvalue of the symplectic matrix, mean photon number, intensity difference fluctuation, photon number variance, and intensity correlation are derived for the cavity-mode radiation. The entanglement produced is studied employing the logarithmic negativity criterion. It is found that pumping atoms from the lower energy state to excited state, introducing the nonlinear crystal into the cavity and coupling the system to a biased noise fluctuation, generate a bright and strong squeezing and entanglement with enhanced statistical properties although the atoms are initially in the ground state.

International Journal of Optics•Sep 2, 2020•3 citations
Analysis of the effects of external pumping on the quantum features of cavity radiation of the two-photon correlated emission laser is presented. It turns out that the pumping process induces the atomic coherence responsible for the entanglement of the cavity radiation as well as the correlation between the photon numbers belonging to different modes, despite the arising vacuum fluctuations. The photon number correlation is found to be very close to 2 where the entanglement is relatively better. Moreover, the mean number of photon pairs decreases with the amplitude of the driving radiation which is one of the practical limitations associated with the pumping mechanism. It is also shown that the mean photon number of the radiation in mode b is less than one-third of that in mode a.
Analysis of the externally induced quantum features of the cavity radiation of the two-photon correlated emission laser is presented. It turns out that the pumping process induces atomic coherence accountable for observing entanglement in the cavity radiation as well as the nonclassical photon number correlation despite the arising vacuum fluctuations. Even though a significant continuous variable entanglement is obtained near threshold in the strong driving limit, increasing the amplitude of the driving radiation more than required for a fixed value of the linear gain coefficient is found to degrade the degree of entanglement. The two-mode squeezing of the superimposed radiation, entanglement of the cavity radiation and mean number of photon pairs increase with the rate at which the atoms are injected into the cavity, but the nonclassical photon number correlation decreases. Moreover, the mean photon number corresponding to the transition from the upper energy level to the intermediate is found to be greater than the transition from the intermediate to the lower. With conceivable practical challenges, it is in principle possible to generate an intense continuous variable entanglement and quantify it via photon count measurements.
Analysis of the effects of dephasing on quantum features of the cavity radiation of externally pumped correlated emission laser is presented. It turns out that entanglement and nonclassical photon number correlations are strongly reliant on the rate at which the atomic coherent superposition decays specially when the amplitude of the driving radiation is smaller. It is, particularly, found that almost perfectly entangled light can be generated while the rate of dephasing and the amplitude of the external driving radiation are kept low in case the atoms are initially prepared in possible maximum coherence. It is also found that the nonclassical behavior of the photon correlation associated with the violation of Cauchy-Schwarz inequality decreases with the rate of dephasing except for some values of the amplitude of the driving radiation.
Analysis of the effects of external pumping on the quantum features, including entanglement, quantum nonlocality and nonclassical photon number correlations, of the cavity radiation of a correlated emission laser is presented. It turns out that the contribution of externally induced coherent superposition in demonstrating quantum nonlocality is significant. Despite the available evidence that entangled states can exhibit nonlocality for certain values of the rate at which the atoms are injected into the cavity and amplitude of the driving radiation, a direct relation between the degree of entanglement and quantum nonlocality cannot be established. However, it seems likely to make a consistent connection between the Cauchy–Schwarz and Bell–Clauser–Horne–Shimony–Holt inequalities. It is evident that comparison among various nonclassical correlations enhances the understanding of the otherwise intricate quantum theoretical predictions.
We present the analysis of the effects of decoherence on quantum features of the cavity radiation of the two-photon-correlated emission laser, employing the stochastic differential equations associated with the normal ordering. We study how a thermal noise entering the cavity affects the squeezing, entanglement amplification, mean number of photon pairs and intensity difference in the cavity radiation. It turns out that the generated light exhibits a two-mode squeezing and entanglement when initially there are more atoms at the lower level, even when the cavity is coupled to a thermal reservoir. It is also found that though the thermal noise entering the cavity degrades the squeezing and entanglement, it significantly increases the mean number of photon pairs of the superimposed radiation.
A detailed analysis of the dynamics of the cavity radiation of a coherently pumped correlated emission laser is presented. The phase fluctuation and dephasing are found to affect the time evolution of the two-mode squeezing and intensity significantly. The intensity and degree of the two-mode squeezing increase at early stages of the process with time, but this trend changes rapidly afterwards. It is also shown that they increase with phase fluctuation and dephasing in the strong driving limit; however, the situation appears to be opposite in the weak driving limit. This essentially suggests that the phase fluctuation and dephasing weaken the coherence induced by a strong driving mechanism so that the spontaneous emission gets a chance. Moreover, the degree of two-mode squeezing turns out to increase with the rate of injection of the atoms into the cavity only at early stages, whereas the mean photon number increases throughout the lasing process. The other important aspect of the phase fluctuation, in this regard, is the relaxation of the time at which the maximum squeezing is manifested as well as the time in which the radiation remains in a squeezed state.
The quantum and statistical properties of light generated by an external classical field in a correlated emission laser with a parametric amplifier and coupled to a squeezed vacuum reservoir are investigated using the combination of the master and stochastic differential equations. First, the solutions of the cavity-mode variables and correlation properties of noise forces associated to the normal ordering are obtained. Next, applying the resulting solutions, the mean photon number of the separate cavity modes and their crosscorrelation, smallest eigenvalue of the symplectic matrix, mean photon number, intensity difference fluctuation, photon number variance, and intensity correlation are derived for the cavity-mode radiation. The entanglement produced is studied employing the logarithmic negativity criterion. It is found that pumping atoms from the lower energy state to excited state, introducing the nonlinear crystal into the cavity and coupling the system to a biased noise fluctuation, generate a bright and strong squeezing and entanglement with enhanced statistical properties although the atoms are initially in the ground state.