Continuous-variable entanglement in a correlated spontaneous emission laser

Abstract

We discuss the generation and evolution of entangled light in a correlated spontaneous emission laser. The master equation for the two-mode field in a cavity is derived and solved analytically. The time-dependent characteristic function in the Wigner representation for the two-mode field is obtained. It shows that the two-mode field in the cavity evolves in a two-mode Gaussian state. The entanglement degree of the two-mode field in the cavity increases initially, then decreases, and finally vanishes as the field evolves from an initial vacuum. The period of the entanglement is extended as the intensity of the driving field is increased. It is found that the entanglement still exists even when the two-mode squeezing disappears. During the entanglement period, the intensity of the field is amplified. The entanglement for the initial field being a two-mode squeezed vacuum and the entanglement of the output field are also discussed.

Entanglement conditions for two-mode states: Applications

“…These conditions are expressed in terms of quantities that are at most quadratic in mode creation and annihilation operators. They have been used, for example, to study entanglement in correlated emission laser systems [11,12]. More recently, sufficient conditions for entanglement have been found for a wider class of states [13]- [15].…”

Generation of Genuine Tripartite Macroscopic Entanglement in Y-type System

“…But, since Xiong et al [9] proposed a scheme to generate two-mode macroscopic entangled lights based on correlated spontaneous emission lasers (CSEL), many other schemes based on CSEL system are proposed. For example, Tan et al [10,11] proposed a similar scheme and showed that a macroscopic entangled state between two modes of the radiation field can be built in a cavity. Kiffner [12] proposed a scheme for generating two-mode entanglement in macroscopic light just using a single atom.…”

“…However, only the two-mode entanglement is considered in those schemes [9][10][11][12]. Multipartite CV entanglement, as a kind of entanglement resource which receives a lot of attentions [2][3][4][5][6][7][8], seems more valuable to be studied for its various applications.…”

“…In the past decades, entangled states between individual qubits have been extensively studied where entanglement is carried by discontinuous states. In recent years, continuous-variable (CV) entanglement has attracted much attention [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] because its many advantages [1]. Traditional schemes of generating CV entanglement is based on the parametric down conversion process [20,21].…”

Single atom as a macroscopic entanglement source

“…Conventionally, continuous variables entanglement is produced in a parametric down-conversion process [8]. Recently, based on the study concerning a two-mode correlated spontaneous emission laser (CEL) [9], it was shown that a CEL can lead to two-mode entanglement even when the average photon number can be very large [10,11]. The scheme using CEL is the result of many-atom dynamics.…”