Noise-resistant optomechanical entanglement via cross-Kerr effect.

Area of Science:

• Quantum Optics
• Optomechanics
• Quantum Information Science

Background:

• Dark mode (DM) effects in optomechanical systems arise from couplings between degenerate mechanical modes and a common cavity mode.
• These dark modes are typically decoupled from the cavity and bright modes, hindering entanglement.
• Thermal noise and DM effects limit the creation and preservation of quantum entanglement in optomechanical systems.

Purpose of the Study:

• To propose a scheme for achieving and enhancing entanglement between optical cavity modes and mechanical modes.
• To overcome the limitations imposed by the dark mode effect and thermal noise.
• To explore the role of cross-Kerr nonlinearity in mediating optomechanical entanglement.

Main Methods:

• Utilizing the cross-Kerr effect to break the dark mode decoupling.
• Analyzing the entanglement properties of the optomechanical system in the presence of cross-Kerr nonlinearity.
• Investigating the system's behavior at non-zero temperatures and its resilience to thermal noise.

Main Results:

• The cross-Kerr effect successfully breaks the dark mode, leading to entanglement between optical and mechanical modes.
• In the dark mode-breaking regime, light and vibrations become entangled, contrasting with the separable state in the unbreaking regime.
• Optomechanical entanglement is significantly enhanced, with the threshold for thermal phonon number increasing by three orders of magnitude.
• The scheme is extendable to systems with N degenerate mechanical modes by introducing N-1 distinct cross-Kerr strengths.

Conclusions:

• The proposed scheme effectively protects and enhances quantum resources against dark mode effects and thermal noise.
• This method provides a pathway for constructing robust entangled optomechanical networks.
• The findings offer a novel approach to controlling and utilizing quantum correlations in complex optomechanical systems.