STUDIES IN THE AREA OF STATISTICAL MECHANICS REPORTED FROM A.E. ALLAHVERDYAN AND CO-RESEARCHERS

Science Letter
November 3, 2009

Allahverdyan and co-researchers

"A basic task of information processing is information transfer
(flow). Here we study a pair of Brownian particles each coupled to
a thermal bath at temperatures T-1 and T-2," scientists in Yerevan,
Armenia report (see also Statistical Mechanics).

"The information flow in such a system is defined via the time-shifted
mutual information. The information flow nullifies at equilibrium,
and its efficiency is defined as the ratio of the flow to the
total entropy production in the system. For a stationary state
the information flows from higher to lower temperatures, and its
efficiency is bounded from above by (max[T-1, T-2])/(vertical bar
T-1-T-2 vertical bar). This upper bound is imposed by the second law
and it quantifies the thermodynamic cost for information flow in the
present class of systems. It can be reached in the adiabatic situation,
where the particles have widely different characteristic times. The
efficiency of heat. low-defined as the heat flow over the total amount
of dissipated heat-is limited from above by the same factor. There
is a complementarity between heat and information flow: the set-up
which is most efficient for the former is the least efficient for
the latter and vice versa. The above bound for the efficiency can be
(transiently) overcome in certain non-stationary situations, but the
efficiency is still limited from above. We study yet another measure of
information processing (transfer entropy) proposed in the literature,"
wrote A.E. Allahverdyan and colleagues.

The researchers concluded: "Though this measure does not require any
thermodynamic cost, the information flow and transfer entropy are
shown to be intimately related for stationary states."

Allahverdyan and colleagues published their study in the Journal
of Statistical Mechanics – Theory and Experiment (Thermodynamic
efficiency of information and heat flow. Journal of Statistical
Mechanics – Theory and Experiment, 2009;():9011).

For additional information, contact A.E. Allahverdyan, Yerevan Physics
Institute, Alikhanian Bros St. 2, Yerevan 375036, Armenia.

The publisher’s contact information for the Journal of Statistical
Mechanics – Theory and Experiment is: IOP Publishing Ltd., Dirac House,
Temple Back, Bristol BS1 6BE, England.