70 research outputs found
Stationary and transient Fluctuation Theorems for effective heat flux between hydrodynamically coupled particles in optical traps
We experimentally study the statistical properties of the energy fluxes
between two trapped Brownian particles, interacting through dissipative
hydrodynamic coupling, submitted to an effective temperature difference , obtained by random forcing the position of one trap. We identify effective
heat fluxes between the two particles and show that they satisfy an exchange
fluctuation theorem (xFT) in the stationary state. We also show that after the
sudden application of a temperature gradient , \resub{the total}
hot-cold flux satisfies \resub{a} transient xFT for any integration time
whereas \resub{the total} cold-hot flux only does it asymptotically for long
times
Simultaneous 3D measurement of the translation and rotation of finite size particles and the flow field in a fully developed turbulent water flow
We report a novel experimental technique that measures simultaneously in
three dimensions the trajectories, the translation, and the rotation of finite
size inertial particles together with the turbulent flow. The flow field is
analyzed by tracking the temporal evolution of small fluorescent tracer
particles. The inertial particles consist of a super-absorbent polymer that
renders them index and density matched with water and thus invisible. The
particles are marked by inserting at various locations tracer particles into
the polymer. Translation and rotation, as well as the flow field around the
particle are recovered dynamically from the analysis of the marker and tracer
particle trajectories. We apply this technique to study the dynamics of
inertial particles much larger in size (Rp/{\eta} \approx 100) than the
Kolmogorov length scale {\eta} in a von K\'arm\'an swirling water flow
(R{\lambda} \approx 400). We show, using the mixed (particle/fluid) Eulerian
second order velocity structure function, that the interaction zone between the
particle and the flow develops in a spherical shell of width 2Rp around the
particle of radius Rp. This we interpret as an indication of a wake induced by
the particle. This measurement technique has many additional advantages that
will make it useful to address other problems such as particle collisions,
dynamics of non-spherical solid objects, or even of wet granular matter.Comment: 18 pages, 7 figures, submitted to "Measurement Science and
Technology" special issue on "Advances in 3D velocimetry
Toward physical realizations of thermodynamic resource theories
Conventional statistical mechanics describes large systems and averages over
many particles or over many trials. But work, heat, and entropy impact the
small scales that experimentalists can increasingly control, e.g., in
single-molecule experiments. The statistical mechanics of small scales has been
quantified with two toolkits developed in quantum information theory: resource
theories and one-shot information theory. The field has boomed recently, but
the theorems amassed have hardly impacted experiments. Can thermodynamic
resource theories be realized experimentally? Via what steps can we shift the
theory toward physical realizations? Should we care? I present eleven
opportunities in physically realizing thermodynamic resource theories.Comment: Publication information added. Cosmetic change
Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere
Einstein realised that the fluctuations of a Brownian particle can be used to
ascertain properties of its environment. A large number of experiments have
since exploited the Brownian motion of colloidal particles for studies of
dissipative processes, providing insight into soft matter physics, and leading
to applications from energy harvesting to medical imaging. Here we use
optically levitated nanospheres that are heated to investigate the
non-equilibrium properties of the gas surrounding them. Analysing the sphere's
Brownian motion allows us to determine the temperature of the centre-of-mass
motion of the sphere, its surface temperature and the heated gas temperature in
two spatial dimensions. We observe asymmetric heating of the sphere and gas,
with temperatures reaching the melting point of the material. This method
offers new opportunities for accurate temperature measurements with spatial
resolution on the nanoscale, and a new means for testing non-equilibrium
thermodynamicsComment: 5 pages, 4 figures, supplementary material available upon reques
Quantum Fluctuation Theorems
Recent advances in experimental techniques allow one to measure and control
systems at the level of single molecules and atoms. Here gaining information
about fluctuating thermodynamic quantities is crucial for understanding
nonequilibrium thermodynamic behavior of small systems. To achieve this aim,
stochastic thermodynamics offers a theoretical framework, and nonequilibrium
equalities such as Jarzynski equality and fluctuation theorems provide key
information about the fluctuating thermodynamic quantities. We review the
recent progress in quantum fluctuation theorems, including the studies of
Maxwell's demon which plays a crucial role in connecting thermodynamics with
information.Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and
G. Adesso (eds.), "Thermodynamics in the quantum regime - Fundamental Aspects
and New Directions", (Springer International Publishing, 2018
Brownian Carnot engine
The Carnot cycle imposes a fundamental upper limit to the efficiency of a
macroscopic motor operating between two thermal baths. However, this bound
needs to be reinterpreted at microscopic scales, where molecular bio-motors and
some artificial micro-engines operate. As described by stochastic
thermodynamics, energy transfers in microscopic systems are random and thermal
fluctuations induce transient decreases of entropy, allowing for possible
violations of the Carnot limit. Despite its potential relevance for the
development of a thermodynamics of small systems, an experimental study of
microscopic Carnot engines is still lacking. Here we report on an experimental
realization of a Carnot engine with a single optically trapped Brownian
particle as working substance. We present an exhaustive study of the energetics
of the engine and analyze the fluctuations of the finite-time efficiency,
showing that the Carnot bound can be surpassed for a small number of
non-equilibrium cycles. As its macroscopic counterpart, the energetics of our
Carnot device exhibits basic properties that one would expect to observe in any
microscopic energy transducer operating with baths at different temperatures.
Our results characterize the sources of irreversibility in the engine and the
statistical properties of the efficiency -an insight that could inspire novel
strategies in the design of efficient nano-motors.Comment: 7 pages, 7 figure
Cosmic Background Bose Condensation (CBBC)
Degeneracy effects for bosons are more important for smaller particle mass, smaller temperature and higher number density. Bose condensation requires that particles be in the same lowest energy quantum state. We propose a cosmic background Bose condensation, present everywhere, with its particles having the lowest quantum energy state, A c/lambda, with lambda about the size of the visible universe, and therefore unlocalized. This we identify with the quantum of the self gravitational potential energy of any particle, and with the bit of information of minimum energy. The entropy of the universe (similar to 10(122) bits) has the highest number density (similar to 10(36) bits/cm(3)) of particles inside the visible universe, the smallest mass, similar to 10(-66) g, and the smallest temperature, similar to 10(-29) K. Therefore it is the best candidate for a Cosmic Background Bose Condensation (CBBC), a completely calmed fluid, with no viscosity, in a superfluidity state, and possibly responsible for the expansion of the universe.Alfonso-Faus, A.; Fullana Alfonso, MJ. (2013). Cosmic Background Bose Condensation (CBBC). Astrophysics and Space Science. 347(1):193-196. doi:10.1007/s10509-013-1500-8S1931963471Alfonso-Faus, A.: Universality of the self gravitational potential energy of any fundamental particle. Astrophys. Space Sci. 337, 363 (2010a)Alfonso-Faus, A.: The case for the Universe to be a quantum black hole. Astrophys. Space Sci. 325, 113 (2010b)Alfonso-Faus, A.: Galaxies: kinematics as a proof of the existence of a universal field of minimum acceleration. arXiv:0708.0308 (2010c, preprint)Alfonso-Faus, A.: Quantum gravity and information theories linked by the physical properties of the bit. arXiv:1105.3143 (2011, preprint)Anderson, J.D., et al.: Indication, from Pioneer 10/11, Galileo, and Ulysses data, of an apparent anomalous, weak, long-range acceleration. Phys. Rev. Lett. 81, 2858 (1998)Bekenstein, J.D.: Phys. Rev. D 23(2), 287 (1981)Bérut, A., et al.: Experimental verification of Landauer’s principle linking information and thermodynamics. Nature 483, 187 (2012)Drees, M., Chung-Lin, S.: Theoretical interpretation of experimental data from direct dark matter detection. J. Cosmol. Astropart. Phys. 0706, 011 (2007)Eisberg, R., Resnick, R.: Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles, 2nd edn. Wiley, New York (1985)Funo, K., Watanabe, Y., Ueda, M.: Thermodynamic work gain from entanglement. arXiv:1207.6872 [quant-ph] (2012, preprint)Hawking, S.W.: Black hole explosions? Nature 248, 30 (1974)Landauer, R.: Irreversibility and heat generation in the computing process. IBM J. Res. Dev. 5, 183 (1961)Landauer, R.: Dissipation and noise immunity in computation and communication. Nature 335, 779 (1988)Lloyd, S.: Computational capacity of the universe. Phys. Rev. Lett. 88, 237901 (2002)Misner, C.W., Thorne, K.S., Wheeler, J.A.: Gravitation. Freeman, Reading (1973), p. 466 (“Why the energy of the gravitational field cannot be localized”)Scarpa, R., Falomo, R.: Testing Newtonian gravity in the low acceleration regime with globular clusters: the case of omega Centauri revisited. Astron. Astrophys. 523, A43 (2010)Sivaram, C.: Cosmological and quantum constraint on particle masses. Am. J. Phys. 50, 279 (1982)Susskind, L.: The World as a hologram. J. Math. Phys. 36, 6377 (1995)’t Hooft, G.: Dimensional reduction in quantum gravity. arXiv:gr-qc/9310026 (1993, preprint)Toyabe, S., et al.: Experimental demonstration of information-to-energy conversion and validation of the generalized Jarzynski equality. Nat. Phys. 6, 988 (2010)Unruh, W.G.: Notes on black-hole evaporation. Phys. Rev. D, Part. Fields 14(4), 870 (1976)Weinberg, S.: Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity p. 619. Wiley, New York (1972
Heat release by controlled continuous-time Markov jump processes
We derive the equations governing the protocols minimizing the heat released
by a continuous-time Markov jump process on a one-dimensional countable state
space during a transition between assigned initial and final probability
distributions in a finite time horizon. In particular, we identify the
hypotheses on the transition rates under which the optimal control strategy and
the probability distribution of the Markov jump problem obey a system of
differential equations of Hamilton-Bellman-Jacobi-type. As the state-space mesh
tends to zero, these equations converge to those satisfied by the diffusion
process minimizing the heat released in the Langevin formulation of the same
problem. We also show that in full analogy with the continuum case, heat
minimization is equivalent to entropy production minimization. Thus, our
results may be interpreted as a refined version of the second law of
thermodynamics.Comment: final version, section 2.1 revised, 26 pages, 3 figure
Second law, entropy production, and reversibility in thermodynamics of information
We present a pedagogical review of the fundamental concepts in thermodynamics
of information, by focusing on the second law of thermodynamics and the entropy
production. Especially, we discuss the relationship among thermodynamic
reversibility, logical reversibility, and heat emission in the context of the
Landauer principle and clarify that these three concepts are fundamentally
distinct to each other. We also discuss thermodynamics of measurement and
feedback control by Maxwell's demon. We clarify that the demon and the second
law are indeed consistent in the measurement and the feedback processes
individually, by including the mutual information to the entropy production.Comment: 43 pages, 10 figures. As a chapter of: G. Snider et al. (eds.),
"Energy Limits in Computation: A Review of Landauer's Principle, Theory and
Experiments
Physical Foundations of Landauer's Principle
We review the physical foundations of Landauer's Principle, which relates the
loss of information from a computational process to an increase in
thermodynamic entropy. Despite the long history of the Principle, its
fundamental rationale and proper interpretation remain frequently
misunderstood. Contrary to some misinterpretations of the Principle, the mere
transfer of entropy between computational and non-computational subsystems can
occur in a thermodynamically reversible way without increasing total entropy.
However, Landauer's Principle is not about general entropy transfers; rather,
it more specifically concerns the ejection of (all or part of) some correlated
information from a controlled, digital form (e.g., a computed bit) to an
uncontrolled, non-computational form, i.e., as part of a thermal environment.
Any uncontrolled thermal system will, by definition, continually re-randomize
the physical information in its thermal state, from our perspective as
observers who cannot predict the exact dynamical evolution of the microstates
of such environments. Thus, any correlations involving information that is
ejected into and subsequently thermalized by the environment will be lost from
our perspective, resulting directly in an irreversible increase in total
entropy. Avoiding the ejection and thermalization of correlated computational
information motivates the reversible computing paradigm, although the
requirements for computations to be thermodynamically reversible are less
restrictive than frequently described, particularly in the case of stochastic
computational operations. There are interesting possibilities for the design of
computational processes that utilize stochastic, many-to-one computational
operations while nevertheless avoiding net entropy increase that remain to be
fully explored.Comment: 42 pages, 15 figures, extended postprint of a paper published in the
10th Conf. on Reversible Computation (RC18), Leicester, UK, Sep. 201
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