Distant entanglement enhanced in PT -symmetric optomechanics

Abstract

We study steady-state continuous variable entanglement in a three-mode optomechanical system consisting of an active optical cavity (gain) coupled to a passive optical cavity (loss) supporting a mechanical mode. For a driving laser which is blue-detuned, we show that coupling between optical and mechanical modes is enhanced in the unbroken-PT -symmetry regime. We analyze the stability and this shows that steady-state solutions are more stable in the gain and loss systems. We use these stable solutions to generate distant entanglement between the mechanical mode and the optical field inside the gain cavity. It results in a giant enhancement of entanglement compared to what is generated in the single lossy cavity. This work offers the prospect of exploring quantum state engineering and quantum information in such systems. Furthermore, such entanglement opens up an interesting possibility to study spatially separated quantum objects.

Nonclassical light at exceptional points of a quantum PT -symmetric two-mode system

“…(36) The principal squeezing variances, determined along Eqs. (20) and (21), are obtained for arbitrary incident coherent states as:…”

“…This is so due to certain balance between the damping and amplification and other parameters describing an open quantum system. Such Hamiltonians have been successfully used for describing numerous classical physical systems involving optical coupled structures [5][6][7][8], optical waveguides [9,10], optical lattices [11][12][13][14], coupled optical microresonators [15][16][17][18][19], quantum-electrodynamics circuits (QED) [20], optomechanical systems [21,22], systems with complex potentials [23], photonics molecules [24], etc. Enhanced sensing in such systems has been demonstrated [17,25].…”

Quantum Behavior of a PT -Symmetric Two-Mode System with Cross-Kerr Nonlinearity

“…Both solutions in Equations (19) and (20) have the same eigenvalues ν 1,2 = 0 and ν 3,4 = ±i2 √ 2κ in the stability analysis, i.e., no amplification of amplitude fluctuations occur.…”

“…The simplest model of two coupled nonlinear oscillator modes has been generalized to include more oscillators in various configurations. The obtained models were applied in many areas of physics including optical coupled structures [7][8][9][10], optical waveguides [11,12], coupled optical micro-resonators [13][14][15], optical lattices [16][17][18][19], opto-mechanical systems [20,21], etc.…”

The Entanglement Generation in P T -Symmetric Optical Quadrimer System

“…In recent years, the different kinds of P T -symmetric systems have been considered. For instance, there has been the pair of coupled LC circuits [5], optical lattice [6,7], optomechanical system [8], optical waveguides [9], quantum-dot [10], and others. The P T -symmetric systems can exhibit numerous interesting phenomena such as invisibility [11], chaos induced by the P T symmetry breaking [12], and many others.…”