Probabilistic Work Extraction on a Classical Oscillator Beyond the Second Law.

We demonstrate experimentally that, applying optimal protocols that drive the system between two equilibrium states characterized by a free energy difference ΔF, we can maximize the probability of performing the transition between the two states with a work W smaller than ΔF. The second law holds only on average, resulting in the inequality ⟨W⟩≥ΔF. The experiment is performed using an underdamped oscillator evolving in a double-well potential.

Adiabatic computing for optimal thermodynamic efficiency of information processing.

Landauer's principle makes a strong connection between information theory and thermodynamics by stating that erasing a one-bit memory at temperature [Formula: see text] requires an average energy larger than [Formula: see text], with [Formula: see text] Boltzmann's constant. This tiny limit has been saturated in model experiments using quasistatic processes. For faster operations, an overhead proportional to the processing speed and to the memory damping appears.

Spectral fingerprints of nonequilibrium dynamics: The case of a Brownian gyrator.

The same system can exhibit a completely different dynamical behavior when it evolves in equilibrium conditions or when it is driven out-of-equilibrium by, e.g., connecting some of its components to heat baths kept at different temperatures.

Dynamical phase transition in the first-passage probability of a Brownian motion.

We study the first-passage time distribution (FPTD) F(t_{f}|x_{0},L) for a freely diffusing particle starting at x_{0} in one dimension, to a target located at L, averaged over the initial position x_{0} drawn from a normalized distribution (1/σ)g(x_{0}/σ) of finite width σ. We show the averaged FPTD undergoes a sharp dynamical phase transition from a two-peak structure for b=L/σ>b_{c} to a single-peak structure for b View Article and Find Full Text PDF

Simultaneous memory effects in the stress and in the dielectric susceptibility of a stretched polymer glass.

We report experimental evidence that a polymer stretched at constant strain rate λ[over ̇] presents complex memory effects after λ[over ̇] is set to zero at a specific strain λ_{w} for a duration t_{w}, ranging from 100s to 2.2×10^{5}s. When the strain rate is resumed, both the stress and the dielectric constant relax to the unperturbed state nonmonotonically.

Information and Thermodynamics: Fast and Precise Approach to Landauer's Bound in an Underdamped Micromechanical Oscillator.

The Landauer principle states that at least k_{B}Tln2 of energy is required to erase a 1-bit memory, with k_{B}T the thermal energy of the system. We study the effects of inertia on this bound using as one-bit memory an underdamped micromechanical oscillator confined in a double-well potential created by a feedback loop. The potential barrier is precisely tunable in the few k_{B}T range.

Autonomous out-of-equilibrium Maxwell's demon for controlling the energy fluxes produced by thermal fluctuations.

An autonomous out-of-equilibrium Maxwell's demon is used to reverse the natural direction of the heat flux between two electric circuits kept at different temperatures and coupled by the electric thermal noise. The demon does not process any information, but it achieves its goal by using a frequency-dependent coupling with the two reservoirs of the system. There is no mean energy flux between the demon and the system, but the total entropy production (system+demon) is positive.

Lattice Boltzmann simulations of nonequilibrium fluctuations in a nonideal binary mixture.

In recent years the lattice Boltzmann (LB) methodology has been fruitfully extended to include the effects of thermal fluctuations. So far, all studied cases pertain to equilibrium fluctuations, i.e.

Thermal bath engineering for swift equilibration.

We provide a theoretical and experimental protocol that dynamically controls the effective temperature of a thermal bath, through a well-designed noise engineering. We use this powerful technique to shortcut the relaxation of an overdamped Brownian particle in a quadratic potential by a joint time engineering of the confinement strength and of the noise. For an optically trapped colloid, we report an equilibrium recovery time reduced by about two orders of magnitude compared to the natural relaxation time.

Theoretical description of effective heat transfer between two viscously coupled beads.

We analytically study the role of nonconservative forces, namely viscous couplings, on the statistical properties of the energy flux between two Brownian particles kept at different temperatures. From the dynamical model describing the system, we identify an energy flow that satisfies a fluctuation theorem both in the stationary and in transient states. In particular, for the specific case of a linear nonconservative interaction, we derive an exact fluctuation theorem that holds for any measurement time in the transient regime, and which involves the energy flux alone.

Direct calculation of the critical Casimir force in a binary fluid.

We show that critical Casimir effects can be accessed through direct simulation of a model binary fluid passing through the demixing transition. We work in the semi-grand-canonical ensemble, in slab geometry, in which the Casimir force appears as the excess of the generalized pressure, P_{⊥}-nμ. The excesses of the perpendicular pressure, P_{⊥}, and of nμ, are individually of much larger amplitude.

Thermal response of nonequilibrium RC circuits.

We analyze experimental data obtained from an electrical circuit having components at different temperatures, showing how to predict its response to temperature variations. This illustrates in detail how to utilize a recent linear response theory for nonequilibrium overdamped stochastic systems. To validate these results, we introduce a reweighting procedure that mimics the actual realization of the perturbation and allows extracting the susceptibility of the system from steady-state data.

Engineered Swift Equilibration of a Brownian particle.

A fundamental and intrinsic property of any device or natural system is its relaxation time relax, which is the time it takes to return to equilibrium after the sudden change of a control parameter [1]. Reducing , is frequently necessary, and is often obtained by a complex feedback process. To overcome the limitations of such an approach, alternative methods based on driving have been recently demonstrated [2, 3], for isolated quantum and classical systems [4-9].

Stationary and Transient Fluctuation Theorems for Effective Heat Fluxes 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, and submitted to an effective temperature difference ΔT, 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 in the stationary state. We also show that after the sudden application of a temperature gradient ΔT, the total hot-cold flux satisfies a transient exchange fluctuation theorem for any integration time, whereas the total cold-hot flux only does it asymptotically for long times.

Phase-transition oscillations induced by a strongly focused laser beam.

We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at T(c)=306.6K and volume fraction ϕ(c)=12.

Simultaneous and accurate measurement of the dielectric constant at many frequencies spanning a wide range.

We present an innovative technique which allows the simultaneous measurement of the dielectric constant of a material at many frequencies, spanning a four orders of magnitude range chosen between 10(-2) Hz and 10(4) Hz. The sensitivity and accuracy are comparable to those obtained using standard single frequency techniques. The technique is based on three new and simple features: (a) the precise real time correction of the amplification of a current amplifier, (b) the specific shape of the excitation signal and its frequency spectrum, and (c) the precise synchronization between the generation of the excitation signal and the acquisition of the dielectric response signal.

Sound and light from fractures in scintillators.

Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in Bi4Ge3O12, CdWO4, and ZnWO4, in various mechanical configurations at room temperature and ambient pressure. We analyze the temporal and amplitude correlations between the light emission and the acoustic emission during fracture.

Heat flux and entropy produced by thermal fluctuations.

We report an experimental and theoretical analysis of the energy exchanged between two conductors kept at different temperature and coupled by the electric thermal noise. Experimentally we determine, as functions of the temperature difference, the heat flux, the out-of-equilibrium variance, and a conservation law for the fluctuating entropy, which we justify theoretically. The system is ruled by the same equations as two Brownian particles kept at different temperatures and coupled by an elastic force.

Experimental study of the effect of disorder on subcritical crack growth dynamics.

The growth dynamics of a single crack in a heterogeneous material under subcritical loading is an intermittent process, and many features of this dynamics have been shown to agree with simple models of thermally activated rupture. In order to better understand the role of material heterogeneities in this process, we study the subcritical propagation of a crack in a sheet of paper in the presence of a distribution of small defects such as holes. The experimental data obtained for two different distributions of holes are discussed in the light of models that predict the slowing down of crack growth when the disorder in the material is increased; however, in contradiction with these theoretical predictions, the experiments result in longer lasting cracks in a more ordered scenario.

Experimental verification of Landauer's principle linking information and thermodynamics.

In 1961, Rolf Landauer argued that the erasure of information is a dissipative process. A minimal quantity of heat, proportional to the thermal energy and called the Landauer bound, is necessarily produced when a classical bit of information is deleted. A direct consequence of this logically irreversible transformation is that the entropy of the environment increases by a finite amount.

Heat fluctuations in a nonequilibrium bath.

We measure the energy fluctuations of a Brownian particle confined by an optical trap in an aging gelatin after a very fast quench (less than 1 ms). The strong nonequilibrium fluctuations due to the assemblage of the gel are interpreted, within the framework of fluctuation theorem, as a heat flux from the particle towards the bath. We derive an analytical expression of the heat probability distribution, which fits the experimental data and satisfies a fluctuation relation similar to that of a system in contact with two baths at different temperatures.

Experimental verification of a modified fluctuation-dissipation relation for a micron-sized particle in a nonequilibrium steady state.

A modified fluctuation-dissipation theorem for a nonequilibrium steady state is experimentally checked by studying the position fluctuations of a colloidal particle whose motion is confined in a toroidal optical trap. The nonequilibrium steady state is generated by means of a rotating laser beam which exerts on the particle a sinusoidal conservative force plus a constant nonconservative one. The modified fluctuation-dissipation theorem is perfectly verified by the experimental data.

Aging and effective temperatures near a critical point.

The orientation fluctuations of the director of a liquid crystal are measured after a quench near the Fréedericksz transition, which is a second order transition driven by an electric field. We report experimental evidence that, because of the critical slowing down, the liquid crystal presents several properties of an aging system after the quench, such as power law scaling in times of correlation and response functions. During this slow relaxation, a well defined effective temperature, much larger than the heat bath temperature, can be measured using the fluctuation dissipation relation.

Surface oscillations and slow crack growth controlled by creep dynamics of necking instability in a glassy film.

We study experimentally the slow growth of a single crack in a glassy film of polycarbonate submitted to uniaxial and constant imposed load. Flame-shaped macroscopic zones of plastic deformation appear at the tips of the crack and the formation of these plastic zones involves a necking instability. In order to understand the crack growth dynamics, we study first the growth dynamics of the plastic zones alone, i.