Theoretical Physics

29 September 2015
Time: 14:00 to 00:00
Location: EC Stoner 8.60

Theoretical Physics Seminar: Roberto Serra (UFABC)

Avoiding irreversibility in an experimental implementation of a quantum heat engine.

Irreversibility is one of the most intriguing concepts in physics.
While microscopic physical laws are perfectly reversible, macroscopic
average behaviour has a preferred direction of time. This concept
became even more intriguing at the level of a single (few) quantum
system(s). At this scale, energy functions cannot be disregarded and
fluctuation relations rule the non-equilibrium thermodynamic
quantities. According to the second law of thermodynamics, there is an
arrow of time associated with a positive mean entropy production. We
investigate the concept of irreversibility from a microscopic quantum
standpoint, employing a quenched spin-1/2 system in an NMR setup. We
will also present an experimental implementation of a quantum heat
engine, where the work substance is a nuclear spin-1/2 in a molecular
sample. The completely characterization of all energy (work and heat)
fluctuations in the non-equilibrium operation of such engine, will be
discussed. Finally, we present a way to suppress (at least partially)
the entropy production along the quantum thermodynamic cycle,
employing a super-adiabatic driving.



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