arXiv subjects

Xin-Ze Song

Publications and source records attributed to Xin-Ze Song.

3 recordsLinked to original sources

arXiv2026

Asymmetric quantum steering harvested near a Lorentz-violating BTZ black hole

We investigate the harvesting of quantum steering and its directional asymmetry between two Unruh-DeWitt detectors in a Lorentz-violating BTZ black hole spacetime. Since the detectors are located at different radial positions outside the black hole, they experience inequivalent local environments induced by gravitational redshift, causing Alice to undergo stronger effective thermal noise than Bob. Remarkably, we uncover a counterintuitive phenomenon in which the detector subjected to a higher effective temperature exhibits stronger steerability than the other one, revealing a nontrivial inversion of thermal intuition in curved spacetime. Furthermore, quantum steering survives only within a finite window of detector energy gaps and reaches its maximum within an optimal regime. We find that Lorentz violation suppresses steering most strongly near this optimal energy gap, indicating an enhanced sensitivity of maximal correlation extraction to symmetry breaking effects. Our results demonstrate that Lorentz violation acts as a geometric constraint on the quantum information capacity of spacetime, simultaneously restricting both the strength and the directionality of quantum correlations.

gr-qc↗

arXiv2025

Unified signal response for stochastic resonance in bistable systems

The phenomenon of stochastic resonance, wherein the stimulus-response of a system can be maximized by an intermediate level of noise, has been extensively investigated through linear response theory. As yet a unified response-noise or response-frequency formula embracing diverse factors, such as noise color, damping coefficients, and coupling, is still lacking. In the present work, we theoretically investigate the benefit roles of Gaussian white noise and Ornstein- Uhlenbeck noise on the signal amplification of systems ranging from a single overdamped bistable particle to the mean-field coupled underdamped Duffing oscillators and severally deduce their signal response expressions. We find that the formulas of signal response in these different cases can be reduced to a uniform Lorentz function form. Furthermore, based on the general expression, we explain explicitly the role of driving frequency, coupling and the noise color on stochastic resonance. Our results contribute to a deep theoretical understanding of stochastic resonance in bistable systems.

nlin.AO↗

arXiv2025

Optimizing and reducing stochastic resonance by noise color in globally coupled bistable systems

We investigate the collective signal response of two typical nonlinear dynamical models, the mean-field coupled overdamped bistable oscillators and the underdamped Duffing oscillators, with respect to both the additive Ornstein-Uhlenbeck noise and the weak periodical stimulus. Based on the linear response theory, we theoretically derive the dependences of the ensemble signal response on the noise intensity and driving frequency of both systems. Furthermore, we theoretically demonstrate that the noise color monotonically weakens the strength of stochastic resonance in the overdamped situation, but nonmonotonically strengthens it in the underdamped counterpart. Such a result goes against the conventional wisdom that the color of the additive noise impairs the magnitude of stochastic resonance. Finally, we perform the numerical integration to verify our theoretical results and discuss potential connections with the functional significance of 1/f noise.

physics.bio-ph↗