5,670 research outputs found
Work and information processing in a solvable model of Maxwell's demon
We describe a minimal model of an autonomous Maxwell demon, a device that
delivers work by rectifying thermal fluctuations while simultaneously writing
information to a memory register. We solve exactly for the steady-state
behavior of our model, and we construct its phase diagram. We find that our
device can also act as a "Landauer eraser", using externally supplied work to
remove information from the memory register. By exposing an explicit,
transparent mechanism of operation, our model offers a simple paradigm for
investigating the thermodynamics of information processing by small systems.Comment: Main Text (6 pages, 3 figures) + Suppl. Info. (3 pages). To appear in
PNA
Second Law-Like Inequalities with Quantum Relative Entropy: An Introduction
We review the fundamental properties of the quantum relative entropy for
finite-dimensional Hilbert spaces. In particular, we focus on several
inequalities that are related to the second law of thermodynamics, where the
positivity and the monotonicity of the quantum relative entropy play key roles;
these properties are directly applicable to derivations of the second law
(e.g., the Clausius inequality). Moreover, the positivity is closely related to
the quantum fluctuation theorem, while the monotonicity leads to a quantum
version of the Hatano-Sasa inequality for nonequilibrium steady states. Based
on the monotonicity, we also discuss the data processing inequality for the
quantum mutual information, which has a similar mathematical structure to that
of the second law. Moreover, we derive a generalized second law with quantum
feedback control. In addition, we review a proof of the monotonicity in line
with Petz.Comment: As a chapter of: M. Nakahara and S. Tanaka (eds.), "Lectures on
Quantum Computing, Thermodynamics and Statistical Physics", Kinki University
Series on Quantum Computing (World Scientific, 2012
- …