浙江大学景俊团队报道利用低频振荡器实现机械动态卡西米尔效应。该研究于2025年2月20日发表于国际一流学术期刊《物理评论A》上。

研究人员提出，在一个由空腔模式、低频机械振子和二能级原子系统组成的混合光力学系统中，实现机械动态卡西米尔效应（MDCE）。用有效哈密顿量描述，机械能通过三波混频机制直接转化为光子。它不是像超导电路那样对参数DCE的量子模拟。

利用主方程方法，研究人员分析了系统在不同状态下的动力学特性，考虑了系统的有效耦合强度与损失率之比。在强耦合状态下的动力学证实了通过机械和原子激发湮灭，产生光子的各种三波混合过程。在弱耦合状态下，可以通过驱动机械振荡器和原子来证明光子的连续产生。

利用频率可调的原子，该方法避免了双光子共振光机械系统中传统DCE所需要的高频机械振荡器，而这种高频机械振荡器是实验无法达到的。研究发现机械频率可以比腔模式小两个数量级，从而产生显著的DCE光子通量。

附：英文原文

Title: Realizing a mechanical dynamical Casimir effect with a low-frequency oscillator

Author: Tian-hao Jiang, Jun Jing

Issue&Volume: 2025/02/20

Abstract: We propose to realize a mechanical dynamical Casimir effect (MDCE) in a hybrid optomechanical system consisting of a cavity mode, a low-frequency mechanical oscillator, and a two-level atomic system. Described by the effective Hamiltonian, the mechanical energy is directly converted to the photons through a three-wave-mixing mechanism. It is not a quantum simulation of a parametric DCE such as in superconducting circuits. Using a master-equation approach, we analyze the system dynamics in various regimes with respect to the ratio of the effective coupling strength and the loss rate of the system. The dynamics under the strong-coupling regime confirms various three-wave-mixing processes for creating photons by annihilation of mechanical and atomic excitations. Under the weak-coupling regime, a continuous production of photons can be demonstrated by driving both the mechanical oscillator and atom. By virtue of an atom of tunable frequency, our method avoids using the high-frequency mechanical oscillator, which is required for the conventional DCE in optomechanical systems under the double-photon resonance yet is out of reach of experiment. It is found that the mechanical frequency can be about two orders smaller than the cavity mode in yielding a remarkable flux of DCE photons.

DOI: 10.1103/PhysRevA.111.022811

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.111.022811