scholarly journals Enhancing Steady-State Entanglement Generated by a Nondegenerate Three-Level Laser with Thermal Reservoir

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tamirat Abebe ◽  
Tewodros Yirgashewa ◽  
Abebe Belay
Keyword(s):  
Steady State ◽  
Large Time ◽  
Approximation Scheme ◽  
Atomic State ◽  
Expectation Values ◽  
Normal Ordering ◽  
Time Approximation ◽  
Thermal Reservoir ◽  
Level Laser ◽  
Cavity Radiation

We analyze a nondegenerate three-level cascade laser with an open cavity and coupled to a two-mode thermal reservoir employing the stochastic differential equations for atomic operators associated with the normal ordering. Applying the large-time approximation scheme, we obtain the solutions for the corresponding equations of evolution of the expectation values of atomic operators. Furthermore, employing the resulting solutions, we studied the photon as well as cavity atomic-state entanglement amplification of the cavity radiation.

scholarly journals Quantum Entanglement and its Quantification in a Two-Mode Cascade Laser

2021 ◽  
pp. 1-8
Author(s):  
Ebisa Mosisa Kanea ◽  
Keyword(s):  
Master Equation ◽  
Quantum Entanglement ◽  
Normal Ordering ◽  
Logarithmic Negativity ◽  
Squeezed Vacuum ◽  
Level Laser ◽  
Cavity Radiation ◽  
Schwartz Inequality ◽  
Correlation Properties ◽  
Degree Of Entanglement

In this paper, quantum entanglement of correlated two-mode light generated by a three-level laser coupled to a two-mode squeezed vacuum reservoir is thoroughly analyzed using different inseparability criteria, using the master equation, we obtain the stochastic dierential equation and the correlation properties of the noise forces associated with the normal ordering. Next, we study the photon entanglement by considering different inseparability criteria. In particular, the criteria applied are Duan-Giedke-Cirac-Zoller (DGCZ) criterion, logarithmic negativity, Hillery-Zubairy, and Cauchy-Schwartz inequality and we found that the presence of the squeezing parameter leads to an increase in the degree of entanglement. Moreover, the linear gain coecient significantly achieved the degree of entanglement for the cavity radiation

scholarly journals The Quantum Analysis of Nonlinear Optical Parametric Processes with Thermal Reservoirs

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Tamirat Abebe ◽  
Nebiyu Gemechu ◽  
Chimdessa Gashu ◽  
Kebede Shogile ◽  
Solomon Hailemariam ◽  
...  
Keyword(s):  
Nonlinear Crystal ◽  
Photon Number ◽  
Laser Cavity ◽  
Normal Ordering ◽  
Thermal Reservoir ◽  
Quantum Analysis ◽  
Cavity Radiation ◽  
Cavity Modes ◽  
The Mean ◽  
Parametric Processes

In this paper, employing the stochastic differential equations associated with the normal ordering, the quantum properties of a nondegenerate three-level cascade laser with a parametric amplifier and coupled to a two-mode thermal reservoir are thoroughly analyzed. Particularly, the enhancement of squeezing and the amplification of photon entanglement of the two-mode cavity light are investigated. It is found that the two cavity modes are strongly entangled and the degree of entanglement is directly related to the two-mode squeezing. Despite the fact that the entanglement and squeezing decrease with the increment of the mean photon number of the thermal reservoir, strong amount of these nonclassical properties can be generated for a considerable amount of thermal noise with the help of the nonlinear crystal introduced into the laser cavity. Moreover, the squeezing and entanglement of the cavity radiation enhance with the rate of atomic injection.

scholarly journals The Quantum analysis of Nondegenerate Three-Level Laser with Spontaneous Emission and Noiseless Vacuum Reservoir

2018 ◽  
Vol 63 (11) ◽  
pp. 969 ◽  
Author(s):  
T. Abebe
Keyword(s):  
Spontaneous Emission ◽  
Photon Number ◽  
State Level ◽  
Vacuum State ◽  
Langevin Equations ◽  
Normal Ordering ◽  
Squeezed Light ◽  
Quantum Analysis ◽  
Level Laser ◽  
Cavity Radiation

The analysis of quantum properties of the cavity light produced by a coherently driven nondegenerate three-level laser possessing an open cavity and coupled to a two-mode vacuum reservoir is presented. The normal ordering of noise operators associated with the vacuum reservoir is considered. Applying the solutions of the equations of evolution for the expectation values of the atomic operators and the quantum Langevin equations for the cavity mode operators, the squeezing properties, entanglement amplification, and the normalized second-order correlation function of the cavity radiation are described. The three-level laser generates squeezed light under certain conditions, with maximum intracavity squeezing being 50% below the vacuum-state level. Moreover, it is found that the presence of spontaneous emission increases the quadrature squeezing and entanglement and decreses the mean photon number of the two-mode cavity radiation.

scholarly journals Dynamics of the Cavity Radiation of a Correlated Emis-sion Laser Coupled to a Two-Mode Thermal Reservoir

2021 ◽  
Vol 66 (12) ◽  
pp. 1027
Author(s):  
B. Alemu ◽  
Ch. Gashu ◽  
E. Mosisa ◽  
T. Abebe
Keyword(s):  
State Level ◽  
Vacuum State ◽  
Quantum Processes ◽  
Normal Order ◽  
Thermal Reservoir ◽  
Quantum Properties ◽  
Level Laser ◽  
Cavity Radiation ◽  
Thermal Light ◽  
Degree Of Entanglement

In this paper, the quantum properties of the cavity light beam produced by a coherently driven nondegenerate three-level laser with an open cavity and coupled to a two-mode thermal reservoir are thoroughly analyzed. We have carried out our analysis by putting the noise operators associated with the thermal reservoir in normal order. Here we discussed more the effect of thermal light and the spontaneous emission on the dynamics of the quantum processes. It is found that the maximum degree of intracavity squeezing 43% below the vacuum-state level. Moreover, the presence of thermal light leads to decrease the degree of entanglement.

scholarly journals Generation of Entangled Light from a Nondegenerate Three-Level Laser Coupled to a Two-Mode Vacuum Reservoir

2021 ◽  
Vol 66 (7) ◽  
pp. 551
Author(s):  
T. Abebe ◽  
Ch. Gashu
Keyword(s):  
Differential Equations ◽  
Master Equation ◽  
Stochastic Differential Equations ◽  
Normal Ordering ◽  
Quantum Properties ◽  
Level Laser ◽  
Cavity Radiation ◽  
Cavity Modes ◽  
Degree Of Entanglement

The quantum properties of a nondegenerate three-level cascade laser coupled to a two-mode vacuum reservoir are throughly analyzed with the use of the pertinent master equation and stochastic differential equations associated with the normal ordering. Particularly, the enhancement of squeezing and the amplification of photon entanglement of the two-mode cavity light are investigated. It is found that the two cavity modes are strongly entangled, and the degree of entanglement is directly related to the two-mode squeezing. Moreover, the squeezing and entanglement of the cavity radiation enhance with the rate of atomic injection.

A Design Method for Modified Smith Predictors for Non-Minimum-Phase Time-Delay Plants with Multiple Feedback-Connected Time-Delays

2010 ◽  
Vol 36 ◽  
pp. 253-262 ◽  
Author(s):  
Iwanori Murakami ◽  
Nghia Thi Mai ◽  
Kou Yamada ◽  
Takaaki Hagiwara ◽  
Yoshinori Ando ◽  
...  
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Time Delays ◽  
Large Time ◽  
Design Method ◽  
Smith Predictor ◽  
Minimum Phase ◽  
Effective Time ◽  
Phase Time ◽  
Step Disturbance

In this paper, we examine a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays. The Smith predictor is proposed by Smith to overcome time-delay and known as an effective time-delay compensator for a plant with large time-delay. The Smith predictor by Smith cannot be used for plants having an integral mode, because a step disturbance will result in a steady state error. Several papers considered the problem to design modified Smith predictors for unstable plants. However, no paper examines a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays. In this paper, we examine a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays.

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