Quantum thermodynamics and the emergence of irreversibility

Understanding the origin of irreversibility is a challenging problem in fundamental physics. When a quantum system is not treated in isolation – but interacts with its surrounding environment – its quantum nature rapidly dissipates due to an irreversible physical process called decoherence.

This area of research seeks to understand the link between microscopic and macroscopic irreversibility and provide a unified theoretical framework in which macroscopic dynamics can be understood from the underlying quantum mechanics. In turn, this will shed light on the source of irreversibility, the emergence of the arrow of time, and the quantum-classical transition.

Research aims

We will analyse the impact of different environmental dynamics on macroscopic thermodynamic properties, and assess distinct scenarios to derive irreversible behaviours from classical and quantum microscopic dynamics.

We will derive master equations of open quantum systems with no timescale separation, focusing in particular on extremely reach memory systems, described in terms of fractional dynamics. We will then obtain the corresponding classical limit, and study in detail the emerging thermodynamic properties of these systems, including fluctuation-dissipation relations and the corresponding entropy functions.

We will also compare these scenarios with the thermodynamics of small systems, and identify possible features distinguishing between different dynamics.

References

S. Lally, N. Werren, J. Al-Khalili, and A. Rocco, Master equation for non-Markovian quantum Brownian motion: The emergence of lateral coherences, Phys. Rev. A 105, 012209 (2022).
Rio, L., Åberg, J., Renner, R., Dahlsten, O., Vedral, V., The thermodynamic meaning of negative entropy. Nature 474, 61–63 (2011)
P. Grigolini, A. Rocco and B.J. West, Fractional Calculus as a Macroscopic Manifestation of Randomness, Phys. Rev. E 59 2603 (1999)