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Bart Cleuren

Publications and source records attributed to Bart Cleuren.

At least 19 recordsLinked to original sources
arXiv2026

Performance of Nanoring-based Transparent Conductors: a Computational Investigation

Metallic nanoring networks can serve as promising flexible transparent electrodes. These materials are crucial components in a wide range of applications, including solar cells, touchscreens and displays. In this work, a computational investigation considers in detail (i) the electrical conductance and optical performance of nanoring networks and (ii) the breakdown of these networks due to electrical damage. The electrical resistance of both the nanorings and the contacts between the rings (junctions) is taken into account. In part (i), the effects of 5 parameters on the electrical sheet resistance and optical transparency are presented. It is shown that several parameter combinations achieve better performance in comparison to indium tin oxide, currently the most widely used transparent electrode. In part (ii), due to electrical damage, the nanoring systems display the formation of a crack, running parallel to the vertical terminals, where a voltage difference is applied. The network degradation is measured by its sheet resistance, and a universal effect is observed: networks with varying filling factors exhibit the same degradation profile.

cond-mat.mtrl-sci↗
arXiv2026

Impedance in Periodically Driven Stochastic Systems

We study the time-dependent currents arising in periodically driven stochastic systems. In the linear regime of small driving, a closed expression is obtained for the impedance/admittance associated with these currents. This expression leads directly to an interpretation in terms of an equivalent electrical circuit. For a stochastic system with $N$ states, the electrical circuit consists of precisely $N$ parallel branches, with each branch comprising a resistor and a capacitor in series. The low- and high-frequency limits of these currents are calculated, and the results are generalized to more general current expressions. We demonstrate our findings across several archetypal settings, illustrating the potential to detect specific broken symmetries or the graph topology associated with the stochastic process.

cond-mat.stat-mech↗
arXiv2026

Universal features of nonequilibrium Ising models in contact with two thermal reservoirs

We derive generic properties of nonequilibrium phase transitions in all-to-all Ising models placed in contact with two thermal reservoirs, in which parameters (temperatures, interactions and field parameters) assume arbitrary values depending on the contact with each thermal bath. The presence of different kinds of external parameters leads to remarkably different sort of phase transitions. While continuous, discontinuous and even tricritical points are presented when external parameters are symmetric (e.g. the case of energetic barriers or different couplings between the system and thermal baths), the tricriticality is absent when external parameters are antisymmetric (e.g. the case of magnetic fields or biased drivings) implying that solely critical or discontinuous are possible. In such latter case, the probability distribution acquires the Boltzmann-Gibbs like form, irrespectively the model parameters when the switching between thermal reservoirs is sufficiently fast. Our work sheds light about the differences between equilibrium and nonequilibrium ingredients and theirs consequences upon phase transitions.

cond-mat.stat-mech↗
arXiv2026

Sorting by Resetting

A novel paradigm for sorting is introduced, based upon resetting. Using simple examples, we demonstrate that sorting is achieved by resetting the velocity component(s) or orientation of the particles, rather than position. The objects to be sorted are microparticles, modeled as suspended and spatially extended Brownian particles. This sorting-by-resetting scheme illustrates that stochastic resetting can create non-equilibrium conditions which enable tasks forbidden at thermodynamic equilibrium.

cond-mat.stat-mech↗
arXiv2024

Splitting of nonequilibrium phase transitions in driven Ising models

Spontaneous symmetry breaking occurs in various equilibrium and nonequilibrium systems, where phase transitions are typically marked by a single critical point that separates ordered and disordered regimes. We reveal a novel phenomenon in which the interplay between different temperatures and driving forces splits the order-disorder transition into two distinct transition points depending on which ordered state initially dominates. Crucially, these two emerging phases have distinct scaling behaviors and thermodynamic properties. To study this, we propose a minimal variant of the Ising model where spins are coupled to two thermal baths and subjected to two opposite driving forces associated to them. Our findings, robust both for all-to-all interactions (where exact solutions are possible) and nearest-neighbor couplings on a square lattice, uncover unique nonequilibrium behaviors and scaling laws for crucial thermodynamic quantities, such as efficiency, dissipation, power and its fluctuations, that are different between the two ordered phases. We also highlight that one of these emerging phases enables heat-engine operations that are less dissipative and show reduced fluctuations. In this setup, the system can also operate near maximum power and efficiency over a wide parameter range. Our results offer new insights into the relevance of phase transitions under nonequilibrium conditions.

cond-mat.stat-mech↗
arXiv2024

Optimizing Cost through Dynamic Stochastic Resetting

The cost of stochastic resetting is considered within the context of a discrete random walk model. In addition to standard stochastic resetting, for which a reset occurs with a certain probability after \emph{each} step, we introduce a novel resetting protocol which we dubbed {\it dynamic resetting}. This protocol entails an additional dynamic constraint related to the direction of successive steps of the random walker. We study this novel protocol for a one-dimensional random walker on an infinite lattice. We analyze the impact of the constraint on the walker's mean-first passage time and the cost (fluctuations) of the resets as a function of distance of target from the resetting location. Further, cost optimized search strategies are discussed.

cond-mat.stat-mech↗
arXiv2023

Microscopic model for a Brownian Translator

A microscopic model for a translational Brownian motor, dubbed as Brownian Translator, is introduced. It is inspired by the Brownian Gyrator of Filliger and Reimann (Filliger and Reimann 2007). The Brownian Translator consists of a spatially asymmetric object moving freely along a line due to perpetual collisions with a surrounding ideal gas. When this gas has an anisotropic temperature, both spatial and temporal symmetries are broken and the object acquires a nonzero drift. Onsager reciprocity implies the opposite phenomenon, that is dragging a spatially asymmetric object in an (initially at) equilibrium gas induces an energy flow that results in anisotropic gas temperatures. Expressions for the dynamical and energetic properties are derived as a series expansion in the mass ratio (of gas particle vs. object). These results are in excellent agreement with molecular dynamics simulations.

cond-mat.stat-mech↗
arXiv2022

Energetics of a Microscopic Feynman Ratchet

A general formalism is derived describing both dynamical and energetic properties of a microscopic Feynman ratchet. Work and heat flows are given as a series expansion in the thermodynamic forces, obtaining analytical expressions for the (non)linear response coefficients. Our results extend previously obtained expressions in the context of a chiral heat pump.

cond-mat.stat-mech↗
arXiv2022

Thermodynamics and efficiency of sequentially collisional Brownian particles: The role of drivings

Brownian particles placed sequentially in contact with distinct thermal reservoirs and subjected to external driving forces are promising candidates for the construction of reliable thermal engines. In this contribution, we address the role of driving forces for enhancing the machine performance. Analytical expressions for thermodynamic quantities such as power output and efficiency are obtained for general driving schemes. A proper choice of these driving schemes substantially increases both power output and efficiency and extends the working regime. Maximizations of power and efficiency, whether with respect to the strength of the force, driving scheme or both have been considered and exemplified for two kind of drivings: a generic power-law and a periodically drivings.

cond-mat.stat-mech↗
arXiv2019

Cable bacteria as long-range biological semiconductors

Filamentous cable bacteria exhibit unprecedented long-range biological electron transport, which takes place in a parallel fibre structure that shows an extraordinary electrical conductivity for a biological material. Still, the underlying electron transport mechanism remains undisclosed. Here we determine the intrinsic electrical properties of individual cable bacterium filaments. We retrieve an equivalent electrical circuit model, characterising cable bacteria as resistive biological wires. Temperature dependent experiments reveal that the charge transport is thermally activated, and can be described with an Arrhenius-type relation over a broad temperature range (-196°C to +50°C), thus excluding metal-like electron transport. Furthermore, when cable bacterium filaments are utilized as the channel in a field-effect transistor, they show n-type transport, indicating that electrons rather than holes are the charge carriers. Electron mobilities are in the order of 10$^{-1}$ cm$^2$/Vs, comparable to many organic semiconductors. This new type of biological centimetre-range semiconductor with low resistivity offers new perspectives for both fundamental studies and applications in (bio)electronics.

physics.bio-ph↗
arXiv2019

Stochastic Impedance

The concept of impedance, which characterises the current response to a periodical driving, is introduced in the context of stochastic transport. In particular, we calculate the impedance for an exactly solvable model, namely the stochastic transport of particles through a single-level quantum dot.

cond-mat.stat-mech↗
arXiv2016

Power-efficiency-dissipation relations in linear thermodynamics

We derive general relations between maximum power, maximum efficiency, and minimum dissipation regimes from linear irreversible thermodynamics. The relations simplify further in the presence of a particular symmetry of the Onsager matrix, which can be derived from detailed balance. The results are illustrated on a periodically driven system and a three terminal device subject to an external magnetic field.

cond-mat.stat-mech↗
arXiv2015

Linear stochastic thermodynamics for periodically driven systems

The theory of linear stochastic thermodynamics is developed for periodically driven systems in contact with a single reservoir. Appropriate thermodynamic forces and fluxes are identified, starting from the entropy production for a Markov process. Onsager coefficients are evaluated, the Onsager-Casimir relations are verified, and explicit expressions are given for an expansion in terms of Fourier components. The results are illustrated on a periodically modulated two level system including the optimization of the power output.

cond-mat.stat-mech↗
arXiv2015

Efficiency of Single Particle Engines

We study the efficiency of a single particle Szilard and Carnot engine. Within a first order correction to the quasi-static limit, the work distribution is found to be Gaussian and the correction factor to average work and efficiency only depends on the piston speed. The stochastic efficiency is studied for both models and the recent findings on efficiency fluctuations are confirmed numerically. Special features are revealed in the zero temperature limit.

cond-mat.stat-mech↗
arXiv2014

Stochastic Efficiency for Effusion as a Thermal Engine

The stochastic efficiency of effusion as a thermal engine is investigated within the framework of stochastic thermodynamics. Explicit results are obtained for the probability distribution of the efficiency both at finite times and in the asymptotic regime of large deviations. The universal features, derived in Verley et al., Nature Communications 5, 4721 (2014), are reproduced. The effusion engine is a good candidate for both the numerical and experimental verification of these predictions.

cond-mat.stat-mech↗
arXiv2014

Fluctuation symmetry in a two-state Markov model

We show that the scaled cumulant generating and large deviation function, associated to a two-state Markov process involving two processes, obey a symmetry relation reminiscent of the fluctuation theorem, independent from any conditions on the transition rates. The Legendre transform leading from the scaled cumulant generating function to the large deviation function is performed in an ingenious way, avoiding the sign problem associated to taking a square root. Applications to the theory of random walks and to the stochastic thermodynamics for a quantum dot are presented.

cond-mat.stat-mech↗
arXiv2013

Efficiency at maximum power of a chemical engine

A cyclically operating chemical engine is considered that converts chemical energy into mechanical work. The working fluid is a gas of finite-sized spherical particles interacting through elastic hard collisions. For a generic transport law for particle uptake and release, the efficiency at maximum power $η$ takes the form 1/2+cΔμ+ O(Δμ^2), with 1/2 a universal constant and $Δμ$ the chemical potential difference between the particle reservoirs. The linear coefficient c is zero for engines featuring a so-called left/right symmetry or particle fluxes that are antisymmetric in the applied chemical potential difference. Remarkably, the leading constant in $η$ is non-universal with respect to an exceptional modification of the transport law. For a nonlinear transport model we obtain η= 1/(θ+1), with θ>0 the power of $Δμ$ in the transport equation

physics.chem-ph↗