Quantum-beat lasers as bright sources of entangled sub-Poissonian light

Abstract

We show that a quantum-beat system with incoherent pump or coherent driving produces an entangled sub-shot-noise laser that operates well above threshold. The numerical results and physical analyses are presented using the combination modes of the lasing fields. The relative mode is decoupled from the active medium and thus remains in its vacuum state, while the sum mode operates well above threshold and has sub-shot-noise. The quantum beat and the sum mode intensity noise reduction combine to yield entanglement between two bright beams and sub-Poissonian photon statistics of the respective beams.

Entanglement between collective fields via phase-dependent electromagnetically induced transparency

“…To clarify the physics, we introduce collective modes of the cavity fields and orthonormal superposition states of excited states. First, two pairs of orthonormal collective modes [33][34][35][36] are defined as…”

“…Essentially, the pair of modes a l and b l are in quantum beats. For the pair of a l and b l modes, the Hermitian operators corresponding to the relative amplitude r l and relative phase ψ l are defined as [33][34][35][36] …”

Quantum state transfer between distant atoms via selectivity photon emission and absorption progresses

“…[1][2][3][4][5][6][7][8][9][10][11]. Over the past few years, a large number of schemes have been proposed for generating QST in various quantum systems [12][13][14][15][16][17][18].…”

Voltage-controlled entanglement and quantum-information transfer between spatially separated quantum-dot molecules

“…These quantum information processes always require generation of entanglement and implementation of quantum state transfer (QST) [4][5][6][7][8][9][10]. In recent years, a large number of theoretical and experimental schemes have been proposed for generating entanglement [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and QST [28][29][30][31][32][33][34][35] in various quantum systems. For example, Eibl et al [11] proposed a scheme for realizing the three-photon polarization-entangled state based on the spontaneous parametric down-conversion process.…”