20 research outputs found
Differential Landauer's principle
Landauer's principle states that the erasure of information must be a
dissipative process. In this paper, we carefully analyze the recording and
erasure of information on a physical memory. On the one hand, we show that in
order to record some information, the memory has to be driven out of
equilibrium. On the other hand, we derive a differential version of Landauer's
principle: We link the rate at which entropy is produced at every time of the
erasure process to the rate at which information is erased.Comment: 11 pages, 6 figure
Maxwell demons in phase space
Although there is not a complete "proof" of the second law of thermo-
dynamics based on microscopic dynamics, two properties of Hamiltonian systems
have been used to prove the impossibility of work extraction from a single
thermal reservoir: Liouville's theorem and the adiabatic invariance of the
volume enclosed by an energy shell. In this paper we analyze these two
properties in the Szilard engine and other systems related with the Maxwell
demon. In particular, we recall that the enclosed volume is no longer an
adiabatic invariant in non ergodic systems and explore the consequences of this
on the second law.Comment: 14 pages, to appear in EPJS
Crooks' fluctuation theorem for the fluctuating lattice-Boltzmann model
We probe the validity of Crooks' fluctuation relation on the fluctuating
lattice-Boltzmann model (FLBM), a highly simplified lattice model for a thermal
ideal gas. We drive the system between two thermodynamic equilibrium states and
compute the distribution of the work performed. By comparing the distributions
of the work performed during the forward driving and time reversed driving, we
show that the system satisfies Crooks' relation. The results of the numerical
experiment suggest that the temperature and the free energy of the system are
well defined.Comment: To be published in J. Stat. Mec
Irreversibility and information
This thesis is concerned with the irreversibility of certain information processing operations. The two main results of this thesis concern the recording and erasure of information on a physical memory and the measurement, or acquisition of information by a physical device. These operations are shown to be irreversible, and their degree of irreversibility is related to the amount of information processed
Thermodynamic costs of information processing in sensory adaption
Biological sensory systems react to changes in their surroundings. They are
characterized by fast response and slow adaptation to varying environmental
cues. Insofar as sensory adaptive systems map environmental changes to changes
of their internal degrees of freedom, they can be regarded as computational
devices manipulating information. Landauer established that information is
ultimately physical, and its manipulation subject to the entropic and energetic
bounds of thermodynamics. Thus the fundamental costs of biological sensory
adaptation can be elucidated by tracking how the information the system has
about its environment is altered. These bounds are particularly relevant for
small organisms, which unlike everyday computers operate at very low energies.
In this paper, we establish a general framework for the thermodynamics of
information processing in sensing. With it, we quantify how during sensory
adaptation information about the past is erased, while information about the
present is gathered. This process produces entropy larger than the amount of
old information erased and has an energetic cost bounded by the amount of new
information written to memory. We apply these principles to the E. coli's
chemotaxis pathway during binary ligand concentration changes. In this regime,
we quantify the amount of information stored by each methyl group and show that
receptors consume energy in the range of the information-theoretic minimum. Our
work provides a basis for further inquiries into more complex phenomena, such
as gradient sensing and frequency response.Comment: 17 pages, 6 figure
The thermodynamic cost of measurements
The measurement of thermal fluctuations provides information about the
microscopic state of a thermodynamic system and can be used in order to extract
work from a single heat bath in a suitable cyclic process. We present a minimal
framework for the modeling of a measurement device and we propose a protocol
for the measurement of thermal fluctuations. In this framework, the measurement
of thermal fluctuations naturally leads to the dissipation of work. We
illustrate this framework on a simple two states system inspired by the
Szilard's information engine
Reversible feedback confinement
We present a feedback protocol that is able to confine a system to a single microstate without heat dissipation. The protocol adjusts the Hamiltonian of the system in such a way that the Bayesian posterior distribution after measurement is in equilibrium. As a result, the whole process satisfies feedback reversibility - the process is indistinguishable from its time reversal- and assures the lowest possible dissipation for confinement. In spite of the whole process being reversible it can surprisingly be implemented in finite time. We illustrate the idea with a Brownian particle in a harmonic trap with increasing stiffness and present a general theory of reversible feedback confinement for systems with discrete states. editor's choice Copyright (C) EPLA, 2016
Structuring Factors Of The Cumacean Communities Of The Continental Shelf Of Southeastern Brazil
Irreversibility and information
This thesis is concerned with the irreversibility of certain information processing operations. The two main results of this thesis concern the recording and erasure of information on a physical memory and the measurement, or acquisition of information by a physical device. These operations are shown to be irreversible, and their degree of irreversibility is related to the amount of information processed