Two-Phonon Resonance Drives Multicomponent Mechanical Cat States

TL;DR

This paper demonstrates a method to generate high-purity multicomponent mechanical cat states using linear optomechanical coupling and two-phonon resonance, overcoming limitations of quadratic coupling.

Contribution

It introduces a novel approach leveraging two-phonon resonance in a multimode system with linear coupling to produce complex quantum states.

Findings

Achieved deterministic generation of multicomponent mechanical cat states.

Resonant two-phonon process enhances mechanical state rotations and interference.

Generated states are robust against mechanical and optical losses.

Abstract

Using quadratic optomechanical coupling to prepare high-purity mechanical cat states is not feasible as its strength is several orders weaker than linear optomechanical coupling. Here, using only linear coupling in a multimode system, we achieve strong interaction between photons and two phonons, enabling the deterministic generation of high-purity multicomponent mechanical cats. Mediated by an auxiliary supermode, when other two optical supermodes satisfy the two-phonon resonance condition, the process whereby the annihilation of a high-frequency photon accompanied by the creation of a low-frequency photon and two phonons is strongly enhanced. Such resonant two-phonon process drives multiple rotations and interferences of mechanical coherent states, deterministically generating a multicomponent mechanical cat immune to both mechanical and optical losses. Our work provides an universal strategy for enhancing high-order phonon nonlinearities, paving the way for quantum state engineering, quantum precision measurement and fault-tolerant quantum computation.