Information and entropy in quantum Brownian motion: Thermodynamic entropy versus von Neumann entropy

摘要

We compare the thermodynamic entropy of a quantum Brownian oscillator derivedfrom the partition function of the subsystem with the von Neumann entropy ofits reduced density matrix. At low temperatures we find deviations betweenthese two entropies which are due to the fact that the Brownian particle andits environment are entangled. We give an explanation for these findings andpoint out that these deviations become important in cases where statementsabout the information capacity of the subsystem are associated withthermodynamic properties, as it is the case for the Landauer principle.