Enhancement of entanglement in the nonlinear optical coupler by homodyne-mediated feedback

Ke, Sha-Sha; Cheng, Guiping; Zhang, Lihui; Li, Gao‐xiang

doi:10.1088/0953-4075/40/14/004

Cited by 6 publications

(9 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method is limited by the strength of the optical nonlinearity employed, which is usually very weak, and is further reduced by the cavity damping. It has been shown that feedback can be used to increase the continuous-variable entanglement [290][291][292][293][294][295][296][297][298] generated in this way.…”

Section: Entanglement Creation and Controlmentioning

confidence: 99%

See 1 more Smart Citation

Quantum feedback: Theory, experiments, and applications

et al. 2017

View full text Add to dashboard Cite

The control of individual quantum systems is now a reality in a variety of physical settings. Feedback control is an important class of control methods because of its ability to reduce the effects of noise. In this review we give an introductory overview of the various ways in which feedback may be implemented in quantum systems, the theoretical methods that are currently used to treat it, the experiments in which it has been demonstrated to-date, and its applications. In the last few years there has been rapid experimental progress in the ability to realize quantum measurement and control of mesoscopic systems. We expect that the next few years will see further rapid advances in the precision and sophistication of feedback control protocols realized in the laboratory.

show abstract

Section: Entanglement Creation and Controlmentioning

confidence: 99%

“…A modified proposal in Refs. [291,292] is able to produce a pure steady-state two-mode entangled state by using two independent feedback loops to control the variances of X 1 − X 2 and Y 1 + Y 2 simultaneously.…”

Section: Entanglement Creation and Controlmentioning

confidence: 99%

Quantum feedback: Theory, experiments, and applications

et al. 2017

View full text Add to dashboard Cite

show abstract

“…We also note that an experimental generation system of the optical GHz-like and cluster-like quadripartite entangled states for continuous variables has been designed [25] . Recently, for the purpose of enhancement of squeezing and entanglement, based on feedback, the intracavity entanglement of a nonlinear couple via homodyne-mediated has been investigated [26] .C-V entanglement can be either produced by threelevel atom (s) [18,[27][28][29] or nonlinearly coupled waveguides intracavity [19,20,23,26] . A natural question arises whether we could integrate the three-level atom and nonlinearly coupled waveguides in the cavity together as a device that could enhance the C-V entanglement.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Enhanced continuous-variable entanglement by a pair of nonlinearly coupled waveguides

Ke-quan

Fan

2009

Sci. China Ser. G-Phys. Mech. Astron.

View full text Add to dashboard Cite

We seek to analyze a three-level cascade laser with a pair of nonlinearly coupled waveguides inside the cavity. Applying the pertinent master equation, we investigate the squeezing and entanglement properties intracavity produced by our system. It is shown that with the help of nonlinearly coupled waveguides highly squeezed as well as macroscopic entangled light with high intensity can be achieved.nonlinearly coupled waveguides, three-level cascade laser, continuous-variable entanglement Quantum entanglement plays an important role in quantum computation speedup [1][2][3] , so a great deal of interest has been attracted in quantum entanglement [4][5][6][7][8] . For example, different authors investigate the dynamics of a cavity QED system [9] and an anisotropic two-qubit Heisenberg XYZ model [10] , respectively. Traditionally, entangled state has been deemed as some correlations between individual qubits. However, it has been proved that continuous-variable (C-V) entanglement is a significant part of quantum information theory [11][12][13] . The reason for this is that C-V entanglement can be prepared unconditionally, whereas producing discrete entanglement relies on coincidence measurements. Starting from the first introduction [14] , in experiments and theory the generations of C-V entanglement have been studied [11][12][13] .Recently, the generations of two-mode entanglement are proposed based on different methods [15][16][17][18] . On the other hand, it has been demonstrated both in theory and in experiment that continuous variable entanglement can be generated in nonlinearly coupled waveguides [19][20][21] .Olsen has shown that two evanescently coupled (2) χ parametric down-converters inside a Fabry-Perot cavity can provide tunable source of quadrature squeezing light, EPR correlations and quantum entanglement [22] , and also proved that the intracavity Kerr nonlinear coupler can generate macroscopically intense outputs with C-V entanglement [23] . Bache et al. [24] have introduced a device that the coupler with (2) χ nonlinearity held inside a pumped Fabry-Perot cavity, and analyzed intensity correlations between the modes. We also note that an experimental generation system of the optical GHz-like and cluster-like quadripartite entangled states for continuous variables has been designed [25] . Recently, for the purpose of enhancement of squeezing and entanglement, based on feedback, the intracavity entanglement of a nonlinear couple via homodyne-mediated has been investigated [26] .C-V entanglement can be either produced by threelevel atom (s) [18,[27][28][29] or nonlinearly coupled waveguides intracavity [19,20,23,26] . A natural question arises whether we could integrate the three-level atom and nonlinearly coupled waveguides in the cavity together as a device that could enhance the C-V entanglement. In this paper, we consider a three-level cascade laser interacting with a pair of nonlinearly coupled waveguides.

show abstract

Entropy and variance squeezing for time-dependent two-coupled atoms in an external magnetic field

Abdalla

Lashin

Sadiek

2007

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

A model of a two-coupled two-level atom under the action of an external magnetic field is introduced. The system is assumed to be isotropic and the coupling between the atoms is taken to be explicitly time dependent. Direct solution for the equations of motion in the Heisenberg picture is used to obtain the explicit expression for the dynamical operators when we assumed the coupling parameter is constant. In the meantime we have employed the rotating wave approximation for the case in which the coupling parameter is time dependent. The variance and entropy squeezing for both cases are discussed. It has been shown that the variance squeezing and entropy squeezing are sensitive to any change in the atomic states, so that there is no variance squeezing reported for the case in which one or both the atoms are in the pure states (e.g., lower or excited states). Further, the phenomenon of squeezing is also affected by the value of the coupling parameter, where we have noted that for a strong coupling parameter the squeezing is pronounced for a long period of time.

show abstract

Enhancement of entanglement in the nonlinear optical coupler by homodyne-mediated feedback

Cited by 6 publications

References 34 publications

Quantum feedback: Theory, experiments, and applications

Quantum feedback: Theory, experiments, and applications

Enhanced continuous-variable entanglement by a pair of nonlinearly coupled waveguides

Entropy and variance squeezing for time-dependent two-coupled atoms in an external magnetic field

Contact Info

Product

Resources

About