Evolution of the chaotic field in the laser process: evolution law of density operator and photon number decay

2011 ◽  
Vol 44 (19) ◽  
pp. 195302 ◽  
Author(s):  
Nian-Quan Jiang ◽  
Hong-Yi Fan ◽  
Li-Yun Hu
Keyword(s):  
Density Operator ◽  
Photon Number ◽  
Evolution Law ◽  
Laser Process ◽  
Chaotic Field

ANALYSIS OF THE LASER PROCESS WITH THREE DIFFERENT INITIAL STATES

2014 ◽  
Vol 28 (08) ◽  
pp. 1450029 ◽  
Author(s):  
FUYI YOU ◽  
JUNHUA CHEN ◽  
HONGYI FAN
Keyword(s):  
Photon Number ◽  
Entangled State ◽  
State Representation ◽  
Evolution Law ◽  
Laser Process ◽  
Specific Entropy ◽  
Degree Of Coherence ◽  
The Common ◽  
The Mean ◽  
Initial States

We analyze the laser process with three different initial states using the entangled state representation, obtain the evolution law of the mean photon number, the entropy, the specific entropy, the second degree of coherence and the Wigner functions, and find out the common characteristics of these three processes.

Evolution of the number state in laser process

2015 ◽  
Vol 29 (19) ◽  
pp. 1550139
Author(s):  
Fuyi You ◽  
Junhua Chen ◽  
Hongyi Fan ◽  
Wenhui Jiang
Keyword(s):  
Wigner Function ◽  
Density Operator ◽  
Jacobi Polynomials ◽  
Photon Number ◽  
Laser Process ◽  
Number State ◽  
Degree Of Coherence ◽  
The Mean ◽  
Analytic Expression ◽  
Second Degree

We investigate systematically the evolution of the number state in a laser process by deriving the analytic expression of the density operator and putting it into a normal ordered form. The eigenvalue of the density operator is related to Jacobi polynomials. Then we derive the expression for the mean photon number, the second degree of coherence, the entropy, Wigner function and the photoncount distribution. The nonclassicality is discussed by virtue of the negativity of Wigner function. It is found that the Wigner function is always negative for t < t0, which is independent on the parameter m. On the other hand, the condition for the second degree of coherence larger than 1 is dependent on the parameter m.

scholarly journals Entropy evolution law in a laser process

2013 ◽  
Vol 334 ◽  
pp. 272-279 ◽  
Author(s):  
Jun-hua Chen ◽  
Hong-yi Fan
Keyword(s):  
Evolution Law ◽  
Laser Process

FIELD PURIFICATION OF A GENERAL THREE-LEVEL SYSTEM INTERACTING WITH RADIATION

2003 ◽  
Vol 17 (07) ◽  
pp. 253-262 ◽  
Author(s):  
MAHMOUD ABDEL-ATY
Keyword(s):  
Exact Solution ◽  
Electromagnetic Field ◽  
Density Operator ◽  
Photon Number ◽  
Entangled State ◽  
Level System ◽  
Level Atom ◽  
Coherent Field ◽  
Field Purity ◽  
Intensity Dependent Coupling

In this essay we introduce a new Hamiltonian which represents the interaction between a three-level atom and a single electromagnetic field including arbitrary forms of nonlinearities of both the field and the intensity-dependent coupling. We derive an exact solution for the density operator of the system by means of which we study the field purity for the entangled state of the system. Also, the influences of the nonlinearities on the field purity and mean photon number are examined. Under the condition of an initial coherent field, the field purity shows the collapse-revival phenomenon. It is found that features of these phenomenon are sensitive to the changes of different kinds of the nonlinearities.

Photon-added chaotic field and its damping in a thermo enviroment

2015 ◽  
Vol 93 (4) ◽  
pp. 456-459 ◽  
Author(s):  
Hong-Yi Fan ◽  
Rui He
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Density Operator ◽  
Laguerre Polynomial ◽  
Quantum Field ◽  
Initial Field ◽  
Normal Ordering ◽  
Chaotic Field ◽  
Amplitude Damping Channel ◽  
Time Evolution Equation

We propose a new photon field in quantum field theory, named Laguerre-polynomial-weighted chaotic field. This field will emerge when an initial photon-added chaotic field, which is represented by its density operator [Formula: see text], dissipates in an amplitude damping channel described by time evolution equation [Formula: see text], where κ is a damping coefficient, that is, the initial field will evolve into [Formula: see text] with [Formula: see text], where Ls is the s-order Laguerre-polynomial, and : : denotes normal ordering. We employ the method of summation within an ordered product of operators to obtain our result.

Evolution law of photocounting probability in a diffusion channel

2014 ◽  
Vol 28 (18) ◽  
pp. 1450145 ◽  
Author(s):  
Hong-Yi Fan ◽  
Fang Jia ◽  
Peng-Fei Zhang ◽  
Rui He
Keyword(s):  
Diffusion Process ◽  
Density Operator ◽  
Laguerre Polynomial ◽  
Initial Density ◽  
Optical Fields ◽  
Diffusion Channel ◽  
Normal Ordering ◽  
Evolution Law ◽  
Field L ◽  
New Formula

We find that in optical fields' diffusion process, the l-photocounting probability formula [Formula: see text] at time t = 0 should be generalized to a new formula [Formula: see text] at time t, where ρ(0) is the initial density operator of the field, Ll is the Laguerre polynomial, : : denotes normal ordering, and ξ is the quantum efficiency of the photocounting detector. This new formula brings much convenience for different ρ0, because for deriving [Formula: see text] there is no need to derive the corresponding ρ(t) in the diffusion channel.

Time evolution law of the Laguerre-polynomial-weighted chaotic photon field in an amplitude-damping channel

2015 ◽  
Vol 93 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Cheng Da ◽  
Qian-Fan Chen ◽  
Peng-Fei Zhang ◽  
Hong-Yi Fan
Keyword(s):  
Decay Rate ◽  
Time Evolution ◽  
Generating Function ◽  
Density Operator ◽  
Laguerre Polynomial ◽  
Hermite Polynomials ◽  
Evolution Law ◽  
Amplitude Damping ◽  
Photon Field ◽  
Amplitude Damping Channel

We examine how a Laguerre-polynomial-weighted chaotic photon field (LPWCPF), whose density operator is [Formula: see text], evolves in an amplitude-damping channel. By using a newly derived generating function of two-variable Hermite polynomials we obtain the evolution law of LPWCPF, which turns out to be a new LPWCPF with a new parameter, depending on 1 − e−2κt, where κ represents decay rate. The technique of integration (summation) within an ordered product of operators is used in our discussions.

scholarly journals The Effect of Superposition on the Quantum Features of the Cavity Radiation of a Three-Level Laser

2021 ◽  
Vol 66 (9) ◽  
pp. 761
Author(s):  
D. Ayehu ◽  
A. Chane
Keyword(s):  
Density Operator ◽  
Photon Number ◽  
Quantum Langevin Equation ◽  
Quantum Properties ◽  
Quadrature Squeezing ◽  
Level Laser ◽  
Cavity Radiation ◽  
The Mean ◽  
The Individual ◽  
Light Beams

We study the statistical and squeezing properties of the cavity light produced by a degenerate three-level laser with the use of the solution of the pertinent quantum Langevin equation. Moreover, applying the density operator to the cavity radiation superposition, we investigated the quantum properties of the superposed cavity light beams generated by a pair of degenerate three-level lasers. Superposing the cavity radiation increases the mean and the variance of the photon number without affecting the quadrature squeezing. It is observed that the degree of squeezing of the separate cavity radiation, as well as the superposed cavity radiation, increases with the rate at which the atoms are injected into the cavity. We have also shown that the mean photon number of the superposed cavity radiation is the sum of the mean photon numbers of the individual cavity radiation. However, the variance of the photon number of the superposed cavity radiation turns out to be four times that of the component cavity radiation.

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