We discuss a general situation of a response of a random process under stochastic resetting to an external force. The displacement process is considered to be a Markov one, and it starts anew at resetting events which follow a renewal process (complete resetting). When assuming that the displacement process shows linear response to a weak external force, we ask what kind of the response does...
Recent progress in fabrication methods draws attention to lattice materials. Thanks to their structure lattice materials frequently offer superior performance compared to bulk materials. However, most of them suffer from shear bands. These strain localizations, diagonal to the load direction, are the main mode of failure for lattice materials. Sear bands are due to a very organized periodic...
In developmental systems cells determine their fate by decoding chemical signals, called morphogens. This results in the emergence of gene expression patterns. I will address the problem of gene expression patterns stability in the systems where two interacting and diffusible gene expression products control the size of their own source regions. Such systems are encountered in e.g. spinal cord...
Double-strand breaks (DSBs) of DNA are the most dangerous type of DNA lesions. Unrepaired DSBs may lead to cell death or cancer driving mutations. A deep understanding of the nature of DSBs, DSBs-related structural modifications of DNA, and repair process of DNA damage is critical to the maintenance of genomic integrity in all forms of life. In this presentation, a statistic-based approach for...
Neurons in the brain are wired into adaptive networks that exhibit a range of collective dynamics. Oscillations, for example, are paradigmatic synchronous patterns of neural activity with a defined temporal scale. Neuronal avalanches, in contrast, are scale-free cascades of neural activity, often considered as evidence of brain tuning to criticality. While models have been developed to account...
In the first part of my lecture, I will discuss thermalization, ergodicity, and lack of them in classical systems. I will focus on paradigmatic example of spin glasses, and normal and anomalous diffusion processes. I will turn then to quantum closed systems, which, when perturbed or quenched, tend to “thermalize” in an ergodic way: the reduced density matrix of a block of the system is well...
Traditional Boltzmann-Gibbs statistical mechanics does not apply to systems with unstable interactions, because for such systems the conventional thermodynamic limit does not exist. In unstable systems the ground state energy does not have an additive lower bound, i.e. no lower bound linearly proportional to the number $N$ of particles or degrees of freedom. In this presentation (see [1] for...
As previously demonstrated, the entropy production – a standard measure of irreversibility of thermodynamic processes – is related to generation of correlations between degrees of freedom of the system and its environment [1]. A natural question appears whether such correlations are classical or quantum. This work deals with this problem by investigating noninteracting fermionic and bosonic...
Absolute negative mobility is one of the most paradoxical forms of anomalous transport behaviour. At the first glance it contradicts the superposition principle and the second law of thermodynamics, however, its fascinating nature bridges nonlinearity and nonequlibrium state in which these fundamental rules are no longer valid. We consider a paradigmatic model of the nonlinear Brownian motion...
The investigation of the influence of drift on the behavior of diffusing particles through a polymeric membrane filled with inorganic powder is considered. In this case, we use sodium alginate as a polymer matrix filled with iron oxide nanoparticles. Such membranes can be considered as a mixture of organic and inorganic phases. The first set of analyses examined the impact of drift on...
The ion channels are characterized by a high degree of complexity, largely sensitive to the measurement conditions. The complex dynamics of the processes taking place in biological membranes is nontrivial and difficult to describe by the standard techniques dedicated to signal analysis. It is still unclear what specific mechanism leads to pink noise, which is an averaged effect of ion channel...
The determination of the order of a phase transition can be quite a challenging task. In the thermodynamic limit the situation is clear: in the case of a first--order phase transition we observe discontinuity in the free energy at the critical point leading to the release of a latent heat. This phenomenon is not observable in the case of a continuous phase transition. Therefore, the results...
We investigate a Geometric Brownian Information Engine (GBIE) in the presence of an error-free feedback controller that transforms the information gathered on the state of particles entrapped in mono-lobal geometric detention into extractable work[1,2]. We determine the benchmarks for utilizing the available information in an output work and the optimum operating requisites for best...
Catalytically active nanoparticles are envisioned as principal components for artificial nanomotors. However, theory and experiments report conflicting findings regarding their dynamics. The lack of consensus is mostly caused by a limited understanding of self-propulsion mechanisms at the nanoscale. Here, we focus on a fundamental symmetry of kinetics of catalytic reactions powering the...
A more fundamental understanding of non-equilibrium phenomena involving fluids confined to restricted geometries presents indeed a difficult challenge. Here we explore a novel approach to describe the collective diffusion of Brownian particles confined to a spherical surface by adapting the dynamic density functional theory (DDFT) to this geometry [1]. The ensuing diffusion equation is then...
Based on simultaneous three-color imaging of fluorescently labelled receptors, arrestins and clathrin coated pits, in living cells, we will analyze the dynamics and interaction patterns of membrane bound Adrenergic receptors with cytoplasmic β-arrestin 2 molecules as well as their recruitment to clathrin-coated pits structures (CCP) before internalization.
First, we demonstrate that arrestin...
In [Phys. Rev. E 102, 042121 (2020)] the authors studied an overdamped dynamics of nonequilibrium noise driven Brownian particle dwelling in a spatially periodic potential and discovered a novel class of Brownian, yet non-Gaussian diffusion. The mean square displacement of the particle grows linearly with time and the probability density for the particle position is Gaussian, however, the...
We consider the motion of an over-damped Brownian particle in two-dimensional bilobal confinement driven by a periodic field in the presence of a transverse bias force (G). The confinement results in an entropic bistable potential in a reduced dimension. We calculate the work done and absorbed heat over a period and their mean and relative variance fluctuations in entropy and energy-dominated...
The probability density function (PDF) of the displacement of particles moving in strongly disordered diffusivity landscapes shows an unusual way of convergence to a Gaussian under homogenization$^1$. Namely, at finite times the PDF exhibits a sharp central peak, and the convergence to a Gaussian follows not by smoothing of the PDF but by narrowing of this central peak, which stays sharp even...
Core quantum postulates including the superposition principle and the unitarity of evolutions are natural and strikingly simple. I show that - when supplemented with a limited version of predictability (captured in the textbook accounts by the repeatability postulate) - these core postulates can account for all the symptoms of classicality. In particular, both objective classical reality and...
We design a geometric Brownian information engine by considering over-damped Brownian particles inside a two-dimensional monolobal confinement with irregular width along the transport direction. Under such detention, particles experience an effective entropic potential which has a logarithmic form. We employ a feedback control protocol as an outcome of error-free position measurement [1-2]....
We take inspiration from Feynman–Smoluchowski ratchet-and-pawl thought experiment to build experimentally a Maxwell's demon at human-size.
We use a centimeter blade shafted to a CC-motor. Then, the blade is immersed in a granular gas made of hundreds of millimeter steal beads. The gas stands for an out-of-equilibrium heat bath, and the blade stands for a 1D Brownian particle whose speed is...
I'll present a deterministic classical algorithm to efficiently sample high-quality solutions of certain spin-glass systems that encode hard optimization problems. It employes tensor networks to represent the Gibbs distribution of all possible configurations. Using approximate tensor-network contractions, we can efficiently map the low-energy spectrum of some quasi-two-dimensional...
We investigate the effect of coupling between translational and internal degrees of freedom of composite quantum particles on their localization in a random potential. We show that entanglement between the two degrees of freedom weakens localization due to the upper bound imposed on the inverse participation ratio by purity of a quantum state. We perform numerical calculations for a...
Computer simulation studies of equilibrium phases of matter play a crucial role in many fields, including biophysics, nanotechnology and soft matter science. They can be used as a guidance for synthesis of materials with desired properties. Of especially high interest are simple interaction models, which are easy to implement, but capture the most important characteristics of modelled...
Fractional Brownian motion, a Gaussian non-Markovian self-similar process with stationary long-correlated increments, has been identified to give rise to the anomalous diffusion behavior in a great variety of physical systems. The correlation and diffusion properties of this random motion are fully characterized by its index of self-similarity, or the Hurst exponent.
However, recent single...
We study the motion of individual messenger RNA (mRNA) in the cytoplasm of HeLa cells using single-molecule tracking. The trajectories are analyzed in terms of the mean squared displacement and the power spectral density. We observe that the motion resembles an antipersistent random walk, which suggests fractional Brownian motion as a useful model. However, the trajectories alternate between...
Motility is one of the most salient aspects of cellular behavior. From the functional point of view, it is essential for many tasks cells perform, from forming tissues and organs during development to deploying the immune response during an infection. In addition, cell movements are usually easy to record, therefore allowing to perform quantitative studies of cell behavior.
Despite the...
Several recent developments in relativistic hydrodynamics are discussed with the emphasis on extensions aiming at description of highly off equilibrium systems (anisotropic hydrodynamics) and inclusion of spin polarization phenomena (spin hydrodynamics).
In systems with inertia, solitons are waves whose dispersion is suppressed by nonlinear effects. We demonstrate that solitons can occur also in the absence of inertia in overdamped dynamics of Brownian hard spheres driven through periodic potentials at high density. In such systems, the dispersion of density waves is suppressed due to the fact that particles keep together in clusters and...
Based on classical statistical mechanics, we calculate analytically the length extension under a pulling force of a polymer modeled as a freely jointed chain (FJC) with extensible bonds, the latter being considered as harmonic springs. We obtain an approximated formula for the extension curve that can reproduce with high precision the extension/force curves also at low values of the elastic...
The search for a justification and an appropriate description of irreversible macroscopic dynamics of fluids from time reversible mechanics was initiated Boltzmann, Loschmidt, Einstein and Smoluchowski. However, in spite of the impressive advances on both the experimental and progress addressing statistical nature, it has remained a polemic issue. Nowadays, the focus shifted towards the...
The computing power of current digital hardware is hitting unavoidable physical limits.
Analog hardware has reemerged as an alternative solution for specialized applications.
In particular, neuromorphic computers, using combination of analog and digital elements, are becoming increasingly competitive in machine learning applications, offering high-speed, low-footprint, and low-power...
One route towards capturing solar energy with great efficiency is to fundamentally investigate the way nature is capable of performing the different stages in photo-synthesis. Chlorosomes - large antennae complexes found in Green Sulfur Bacteria - are unique in capturing and transporting photon energy with near 100% quantum efficiency to the reaction centre where electrons and holes are...
Thermal relaxation is a fundamental process in statistical mechanics, with numerous applications in Nature and industry. Nonetheless, the kinetics of relaxation is well understood only close to equilibrium. Far-from-equilibrium relaxation, by contrast, is a genuine non-equilibrium problem that offers fascinating open questions, and a variety of unexpected phenomena.
In my talk, I will discuss...
In this talk we present the study of the trapped motion of a molecule undergoing diffusivity fluctuations inside a harmonic potential. For the same diffusing-diffusivity process, we investigate two possible interpretations. Depending on whether diffusivity fluctuations are interpreted as temperature or friction fluctuations, we show that they display drastically different statistical...
We approach the strong-coupling "thermodynamic limit'' in the open driven Jaynes-Cummings (JC) model. We do so by highlighting the role of quantum fluctuations against the predictions of mean-field theory in three distinct regimes of operation. We set the stage by demonstrating the persistence of photon blockade, predicted in [H. J. Carmichael, Phys. Rev. X 5, 031028 (2015)], as a...
The advent of novel opto-genetics technology allows the recording of brain activity with a resolution never seen before. The characterisation of these very large data sets offers new challenges as well as unique theory-testing opportunities. Here we discuss whether the spatial and temporal correlation of the collective activity of thousands of neurons are tangled as predicted by the theory...
The KPZ equation[1] is connected to a large number of processes, such as atomic deposition, evolution of bacterial colonies, the direct polymer model, the weakly asymmetric simple exclusion process, the totally asymmetric exclusion process, direct d-mer diffusion, fire propagation, turbulent liquid-crystal, spin dynamics, polymer deposition in semiconductors, and etching [2]. We present a...
We address the two-fold applicability of the power spectrum density of the large-conductance voltage- and Ca2+ -activated potassium channels of the inner mitochondrial membrane (mitoBK). First, we will address the estimation of the optimal sampling frequency for the fibroblast's mitoBK patch-clamp data analysis [1], employing the process with doubly harmonic diminution, known to produce pink...
The cerebral cortex exhibits spontaneous activity even in the absence of any task or external stimuli. A salient aspect of this resting-state dynamics, as revealed by in vivo and in vitro measurements, is that it exhibits several patterns, including collective oscillations, emerging out of neural synchronization, as well as highly-heterogeneous outbursts of activity interspersed by periods of...
We show through intensive simulations that the paradigmatic features of anomalous diffusion are indeed the features of a (continuous-time) random walk driven by two different Markovian hopping-trap mechanisms. If p ∈ (0, 1/2) and 1 − p are the probabilities of occurrence of each Markovian mechanism, then the anomalousness parameter β ∈ (0, 1) results to be β ≃ 1 − 1/{1 + log[(1 − p)/p]}....
The transport properties of an extended system driven by active reservoirs is an issue of paramount importance, which remains virtually unexplored. Here we address this issue, for the first time, in the context of energy transport between two active reservoirs connected by a chain of harmonic oscillators. The couplings to the active reservoirs, which exert correlated stochastic forces on the...
