8,297 research outputs found
Thermodynamic uncertainty relations in a linear system
We consider a Brownian particle in harmonic confinement of stiffness , in
one dimension in the underdamped regime. The whole setup is immersed in a heat
bath at temperature . The center of harmonic trap is dragged under any
arbitrary protocol. The thermodynamic uncertainty relations for both position
of the particle and current at time are obtained using the second law of
thermodynamics as well as the positive semi-definite property of the
correlation matrix of work and degrees of freedom of the system for both
underdamped and overdamped cases.Comment: Minor revision, Accepted in EPJ
Anderson localization vs. Mott-Hubbard metal-insulator transition in disordered, interacting lattice fermion systems
We review recent progress in our theoretical understanding of strongly
correlated fermion systems in the presence of disorder. Results were obtained
by the application of a powerful nonperturbative approach, the Dynamical
Mean-Field Theory (DMFT), to interacting disordered lattice fermions. In
particular, we demonstrate that DMFT combined with geometric averaging over
disorder can capture Anderson localization and Mott insulating phases on the
level of one-particle correlation functions. Results are presented for the
ground-state phase diagram of the Anderson-Hubbard model at half filling, both
in the paramagnetic phase and in the presence of antiferromagnetic order. We
find a new antiferromagnetic metal which is stabilized by disorder. Possible
realizations of these quantum phases with ultracold fermions in optical
lattices are discussed.Comment: 25 pages, 5 figures, typos corrected, references update
Quantum Thermodynamics
Quantum thermodynamics addresses the emergence of thermodynamical laws from
quantum mechanics. The link is based on the intimate connection of quantum
thermodynamics with the theory of open quantum systems. Quantum mechanics
inserts dynamics into thermodynamics giving a sound foundation to
finite-time-thermodynamics. The emergence of the 0-law I-law II-law and III-law
of thermodynamics from quantum considerations is presented. The emphasis is on
consistence between the two theories which address the same subject from
different foundations. We claim that inconsistency is the result of faulty
analysis pointing to flaws in approximations
Frenesy: time-symmetric dynamical activity in nonequilibria
We review the concept of dynamical ensembles in nonequilibrium statistical
mechanics as specified from an action functional or Lagrangian on spacetime.
There, under local detailed balance, the breaking of time-reversal invariance
is quantified via the entropy flux, and we revisit some of the consequences for
fluctuation and response theory. Frenesy is the time-symmetric part of the
path-space action with respect to a reference process. It collects the variable
quiescence and dynamical activity as function of the system's trajectory, and
as has been introduced under different forms in studies of nonequilibria. We
discuss its various realizations for physically inspired Markov jump and
diffusion processes and why it matters a good deal for nonequilibrium physics.
This review then serves also as an introduction to the exploration of frenetic
contributions in nonequilibrium phenomena
A nonequilibrium extension of the Clausius heat theorem
We generalize the Clausius (in)equality to overdamped mesoscopic and
macroscopic diffusions in the presence of nonconservative forces. In contrast
to previous frameworks, we use a decomposition scheme for heat which is based
on an exact variant of the Minimum Entropy Production Principle as obtained
from dynamical fluctuation theory. This new extended heat theorem holds true
for arbitrary driving and does not require assumptions of local or close to
equilibrium. The argument remains exactly intact for diffusing fields where the
fields correspond to macroscopic profiles of interacting particles under
hydrodynamic fluctuations. We also show that the change of Shannon entropy is
related to the antisymmetric part under a modified time-reversal of the
time-integrated entropy flux.Comment: 23 pages; v2: manuscript significantly extende
Fermionic Networks: Modeling Adaptive Complex Networks with Fermionic Gases
We study the structure of Fermionic networks, i.e., a model of networks based
on the behavior of fermionic gases, and we analyze dynamical processes over
them. In this model, particle dynamics have been mapped to the domain of
networks, hence a parameter representing the temperature controls the evolution
of the system. In doing so, it is possible to generate adaptive networks, i.e.,
networks whose structure varies over time. As shown in previous works, networks
generated by quantum statistics can undergo critical phenomena as phase
transitions and, moreover, they can be considered as thermodynamic systems. In
this study, we analyze Fermionic networks and opinion dynamics processes over
them, framing this network model as a computational model useful to represent
complex and adaptive systems. Results highlight that a strong relation holds
between the gas temperature and the structure of the achieved networks.
Notably, both the degree distribution and the assortativity vary as the
temperature varies, hence we can state that fermionic networks behave as
adaptive networks. On the other hand, it is worth to highlight that we did not
find relation between outcomes of opinion dynamics processes and the gas
temperature. Therefore, although the latter plays a fundamental role in gas
dynamics, on the network domain its importance is related only to structural
properties of fermionic networks.Comment: 19 pages, 5 figure
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