Perspective: Time irreversibility in systems observed at coarse resolution

Abstract

A broken time-reversal symmetry, i.e. broken detailed balance, is central to non-equilibrium physics and is a prerequisite for life. However, it turns out to be quite challenging to unambiguously define and quantify time-reversal symmetry (and violations thereof) in practice, that is, from observations. Measurements on complex systems have a finite resolution and generally probe low-dimensional projections of the underlying dynamics, which are well known to introduce memory. In situations where many microscopic states become "lumped" onto the same observable "state" or when introducing "reaction coordinates" to reduce the dimensionality of data, signatures of a broken time-reversal symmetry in the microscopic dynamics become distorted or masked. In this perspective we highlight why in defining and discussing time-reversal symmetry, and quantifying its violations, the precise underlying assumptions on the microscopic dynamics, the coarse graining, and further reductions, are not a technical detail. These assumptions decide whether the conclusions that are drawn are physically sound or inconsistent. We summarize recent findings in the field and reflect upon key challenges.

References in corpus (16)

• Thermodynamic uncertainty relation for biomolecular processes
• Dissipation: The phase-space perspective
• State-dependent diffusion: thermodynamic consistency and its path integral formulation
• Lower bounds on dissipation upon coarse graining
• Entropy production of active particles and for particles in active baths
• Fluctuation Relations for Diffusion Processes
• Operationally accessible bounds on fluctuations and entropy production in periodically driven systems
• Symmetries of generating functionals of Langevin processes with colored multiplicative noise
• Perspective: Markov Models for Long-Timescale Biomolecular Dynamics
• Special Topic: Markov Models of Molecular Kinetics
• On the "generalized Generalized Langevin Equation"
• Local detailed balance across scales: from diffusions to jump processes and beyond
• Turbulence: does energy cascade exist?
• On and beyond entropy production: the case of Markov jump processes
• Entropy Production by Underdamped Langevin Dynamics
• Consistent time reversal and reliable and accurate inference in the presence of memory

Cited by in corpus (3)

• Compensating random transition-detection blackouts in Markov networks
• Characteristic oscillations in frequency-resolved heat dissipation of linear time-delayed Langevin systems: Approach from the violation of the fluctuation-response relation
• Macroscopicity and observational deficit in states, operations, and correlations