August 4th-7th, 2014
Yukawa Institute for Theoretical Physics, Kyoto University
"Carnot's Theorem for finite-size systems"
Hiroyasu Tajima (University of Tokyo)
Recent development of experimental techniques enables us to manipulate small-size systems
and to verify the thermodynamic features of such systems.
Micro-thermomotors and Maxwell's demon, which used to be imaginary devices, have been realized in laboratories.
In such microscopic or mesoscopic systems, the efficiency of heat engines is expected to be changed by the finite-size effect.
However, there were no general theory that treats the finite-size effect on the efficiency.
Here, we extend Carnot's theorem toward finite-size systems by using quantum information techniques;
we microscopically derive a general optimal upper bound for the efficiency of finite-size heat engines attached
on finite-size heat baths composed n particles.
Our upper bound is achievable, and converts into the Carnot's efficiency in the limit n → ∞;
therefore our result includes the achievability of Canot efficiency as a corollary.
Our upper bound is easily computable for any n; it gives a quantitative understanding not only in the microscopic
and macroscopic limits, but also in mesoscopic scales.
Our results also clarify that the finiteness of working body does not affect on the efficiency,
i.e., the efficiency is only restricted by the finiteness of heat baths.
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