Speaker
Stefano Bo
(Nordita)
Description
To be able to survive and prosper, cells need to acquire,
exchange and process information under noisy conditions.
Recording multiple measurements is an effective way of
reducing the noise. It is known in general that handling
information has a thermodynamic cost. Inspired by this
biological problem and in view of the relation between
information and thermodynamics we investigate how much
information about an external protocol can be stored
in the memory of a stochastic measurement device given an
energy budget. We consider a layered system with
a memory component storing information about the external
environment by monitoring the history of a sensory
part coupled to the environment. We derive an integral
fluctuation theorem for the entropy production and a measure
of the information accumulated in the memory device. Its
most immediate consequence is that the amount of
information is bounded by the average thermodynamic entropy
produced by the process. At equilibrium no entropy
is produced and therefore the memory device cannot add any
information and is superfluous. Such a device can be used to
model the sensing process of a cell measuring the external
concentration of a chemical compound and encoding the
measurement in the amount of phosphorylated cytoplasmic
proteins.
