Quantum coherence resonance
Quantum coherence resonance
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DOI：
10.1088/1367-2630/abf1d7
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发表时间：
2020-06
影响因子：
3.3
通讯作者：
Yuzuru Kato;H. Nakao
中科院分区：
文献类型：
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作者：
Yuzuru Kato;H. Nakao
结果表明，在量子耗散系统中，可以观察到相干共振现象，即非线性可激发系统中噪声诱导振荡的规律性在某一最佳噪声强度下达到最大。通过对量子主方程的数值模拟，分析了在经典极限下表现出双激发性的量子货车der Pol压缩系统。我们首先证明，量子相干共振发生在半经典制度，即系统的振荡响应的规律性是最大化的量子波动的最佳强度，并解释这种现象类比与经典的噪声可激发系统使用半经典随机微分方程。这种共振在中等强度的量子涨落下仍然存在，半经典描述对此是无效的。此外，我们调查更强的量子制度，并证明系统的响应的规律性可以表现出第二个峰值的量子涨落的强度进一步增加。我们表明，这第二个共振峰是一个强大的量子效应，不能解释的半经典的图片，其中只有少数能量状态参与系统动力学。
It is shown that coherence resonance, a phenomenon in which regularity of noise-induced oscillations in nonlinear excitable systems is maximized at a certain optimal noise intensity, can be observed in quantum dissipative systems. We analyze a quantum van der Pol system subjected to squeezing, which exhibits bistable excitability in the classical limit, by numerical simulations of the quantum master equation. We first demonstrate that quantum coherence resonance occurs in the semiclassical regime, namely, the regularity of the system’s oscillatory response is maximized at an optimal intensity of quantum fluctuations, and interpret this phenomenon by analogy with classical noisy excitable systems using semiclassical stochastic differential equations. This resonance persists under moderately strong quantum fluctuations for which the semiclassical description is invalid. Moreover, we investigate even stronger quantum regimes and demonstrate that the regularity of the system’s response can exhibit the second peak as the intensity of the quantum fluctuations is further increased. We show that this second peak of resonance is a strong quantum effect that cannot be interpreted by a semiclassical picture, in which only a few energy states participate in the system dynamics.