Failure of the fluctuation-dissipation relation to ensure equilibrium

Generic features of the fluctuation dissipation relation in coarsening systems

The integrated response function in phase-ordering systems with scalar, vector, conserved and non conserved order parameter is studied at various space dimensionalities. Assuming scaling of the aging contribution $χ_{ag} (t,t_w)= t_w ^{-a_χ} \hat χ(t/t_w)$ we obtain, by numerical simulations and analytical arguments, the phenomenological formula describing the dimensionality dependence of $a_χ$ in all cases considered. The primary result is that $a_χ$ vanishes continuously as $d$ approaches the lower critical dimensionality $d_L$. This implies that i) the existence of a non trivial fluctuation…

弱驱动过程中黏弹性热浴的最小耗散

Minimal dissipation with viscoelastic baths in weakly driven processes

本文用带记忆的广义 Langevin 方程分析弱驱动过阻尼系统，推导热力学一致条件、两类谐振阱协议的弛豫行为及最小不可逆功协议，揭示黏弹性记忆可加速弛豫并降低耗散。

集群系统中跨尺度的非平衡响应与涨落耗散违反现象

Out of equilibrium response and fluctuation-dissipation violations across scales in flocking systems

本研究针对集群系统的非平衡特性，通过最简模型探究方向扰动下的响应行为，发现涨落耗散关系在局域和全局层面均被违反，违反程度在有序转变处达峰值，阐明了活性与相互作用对集体行为成本分配的作用。

Generalized fluctuation-dissipation relation and statistics for the equilibrium of a system with conformation dependent damping

Liouville's theorem, based on the Hamiltonian flow (micro-canonical ensemble) for a many particle system, indicates that the (stationary) equilibrium probability distribution is a function of the Hamiltonian. A canonical ensemble corresponds to a micro-canonical one at thermodynamic limit. On the contrary, the dynamics of a single Brownian particle (BP) being explicitly non-Hamiltonian with a force and damping term in it and at the other extreme to thermodynamic limit admits the Maxwell-distribution (MD) for its velocity and Boltmann-distribution (BD) for positions (when in a potential). This …

Conditional statistics of temperature fluctuations in turbulent convection

We find that the conditional statistics of temperature difference at fixed values of the locally averaged temperature dissipation rate in turbulent convection become Gaussian in the regime where the mixing dynamics is expected to be driven by buoyancy. Hence, intermittency of the temperature fluctuations in this buoyancy-driven regime can be solely attributed to the variation of the locally averaged temperature dissipation rate. We further obtain the functional behavior of these conditional temperature structure functions. This functional form demonstrates explicitly the failure of dimensional…

Conservation-dissipation formalism of irreversible thermodynamics

We propose a conservation-dissipation formalism (CDF) for coarse-grained descriptions of irreversible processes. This formalism is based on a stability criterion for non-equilibrium thermodynamics. The criterion ensures that non-equilibrium states tend to equilibrium in long time. As a systematic methodology, CDF provides a feasible procedure in choosing non-equilibrium state variables and determining their evolution equations. The equations derived in CDF have a unified elegant form. They are globally hyperbolic, allow a convenient definition of weak solutions, and are amenable to existing nu…