Quantum coherence resonance

• Published in: New journal of physics Vol. 23; no. 4; p. 43018
• Main Authors: Kato, Yuzuru, Nakao, Hiroya
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.04.2021
• Subjects: Coherence; coherence resonance; Differential equations; Energy dissipation; excitable systems; Expanding universe theory; Noise intensity; noise-induced phenomena; nonlinear dynamics; Nonlinear systems; open quantum systems; Physics; Quantum phenomena; Regularity; Resonance; stochastic oscillators; System dynamics
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/abf1d7

Abstract 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.