Speaker
Tapio Ala-Nissilä
(Aalto University)
Description
Fluctuation relations provide a powerful way to study the
stochastic nature of fluctuating thermodynamic variables,
such as (free) energy, entropy, heat and work in small
systems driven beyond the linear response regime [1]. In
driven classical systems, the fluctuating work and its
distribution play an important role in the relevant
fluctuation relations. However, attempts to generalize the
concept of work to open quantum systems have met with some
difficulties. The main problem in quantum mechanics is that
there is no unique work operator, since for irreversible
processes work depends both on the state of the system as
well as the path taken. I will discuss some recent progress
in defining work and its moments for quantum systems within
the two-measurement protocol (TMP) approach, which for
isolated systems coincides with the classical definition of
work in the appropriate limit. In particular, I will show
that using the TMP within the Linblad master equation
formalism allows one to derive (i) a general integral
fluctuation relation and (ii) moments of work for weakly or
nearly adiabatically driven, open quantum systems [2,3].
1. M. Esposito, U. Harbola, and S. Mukamel, Rev. Mod. Phys.
vol. 81, 1665 (2009).
2. S. Suomela, J. Salmilehto, I.G. Savenko, T. Ala-Nissila,
and M. Möttönen, Phys. Rev. E vol. 91, 022126 (2015).
3. S. Suomela, P. Solinas, J.P. Pekola, J. Ankerhold, and T.
Ala-Nissila, Phys. Rev. B vol. 90, 094304 (2014).
