Nonequilibrium Environment Research Articles

Work extraction from quantum coherence in non-equilibrium environment

Ergotropy, which represents the maximum amount of work that can be extracted from a quantum system, has become a focal point of interest in the fields of quantum thermodynamics and information processing. In practical scenarios, the interaction of quantum systems with their surrounding environment is unavoidable. Recent studies have increasingly focused on analyzing open quantum systems affected by non-stationary environmental fluctuations due to their significant impact on various physical scenarios. While much research has concentrated on work extraction from these systems, it often assumes that the environmental degrees of freedom are substantial and that the environment is effectively in equilibrium. This has led us to explore work extraction from quantum systems under non-stationary environmental conditions. In this work, the dynamics of ergotropy will be investigated in a non-equilibrium environment for both Markovian and non-Markovian regime. In this study, both the coherent and incoherent parts of the ergotropy will be considered. It will be shown that for a non-equilibrium environment, the extraction of work is more efficient compared to when the environment is in equilibrium.

ChemPlasKin: A general-purpose program for unified gas and plasma kinetics simulations

This work introduces ChemPlasKin, a freely accessible solver optimized for zero-dimensional (0D) simulations of chemical kinetics of neutral gas in non-equilibrium plasma environments. By integrating the electron Boltzmann equation solver, CppBOLOS, with the open-source combustion library, Cantera, at the source code level, ChemPlasKin computes time-resolved evolution of species concentration and gas temperature in a unified gas–plasma kinetics framework. The model allows high fidelity predictions of both chemical thermal effects and plasma-induced heating, including fast gas heating and slower vibrational–translational relaxation processes. Additionally, a new heat loss model is developed for nanosecond pulsed discharges, specifically within pin–pin electrode configurations. With its versatility, ChemPlasKin is well-suited for a wide range of applications, from plasma-assisted combustion (PAC) to fuel reforming. In this paper, the reliability, accuracy and efficiency of ChemPlasKin are validated through a number of test problems, demonstrating its utility in advancing gas–plasma kinetic studies.

О связи между ослаблением и временем запаздывания узкополосного сигнала в диспергирующей среде

The 1D problem of propagation of a narrowband signal in a homogeneous dispersing medium is considered. It is shown that there is a direct and immediate relationship between the additional (to vacuum) delay time of the signal and its attenuation during propagation in an absorbing medium. It is shown that with an additional delay time of more than several tens of coherence times of uniformly broadened spectral lines of the medium, the signal weakens by hundreds of decibels and therefore practically disappears. On the other hand, when the delay of the signal is less than the coherence time of the medium, its absorption is small. A similar situation arises in an amplifying (thermodynamically nonequilibrium) environment – of course, with the replacement of signal attenuation with its amplification and the replacement of signal delay with its advance. As an example, the propagation of a narrowband signal, the carrier frequency of which is outside the gain band of the space maser, is considered. It is shown that in this case, due to the long lifetime of the excited states of interstellar gas molecules, the signal propagates at superluminal velocity with practically no change in amplitude, which is very rare in problems of this type.

Emergence of Homochirality via Template-Directed Ligation in an RNA Reactor

RNA in extant biological systems is homochiral; it consists exclusively of -ribonucleotides rather than -ribonucleotides. How the homochirality of RNA emerged is not known. Here we use stochastic simulations to quantitatively explore the conditions for RNA homochirality to emerge in the prebiotic scenario of an RNA reactor, in which RNA strands react in a nonequilibrium environment. These reactions include the hybridization, dehybridization, template-directed ligation, and cleavage of RNA strands. The RNA reactor is either closed, with a finite pool of ribonucleotide monomers of both chiralities ( and ), or the reactor is open, with a constant inflow of a racemic mixture of monomers. For the closed reactor, we also consider the interconversion between and monomers via a racemization reaction. We first show that template-free polymerization is unable to reach a high degree of homochirality, due to the lack of autocatalytic amplification. In contrast, in the presence of template-directed ligation, with base pairing and stacking between bases of the same chirality thermodynamically favored, a high degree of homochirality can arise and be maintained provided the nonequilibrium environment overcomes product inhibition, for instance, via temperature cycling. Indeed, if the experimentally observed kinetic stalling of ligation after chiral mismatches is also incorporated, the RNA reactor can evolve towards a fully homochiral state, in which one chirality is entirely lost. This is possible because the kinetic stalling after chiral mismatches effectively implements a chiral cross-inhibition process. Taken together, our model supports a scenario where the emergence of homochirality is assisted by template-directed ligation and polymerization in a nonequilibrium RNA reactor. Published by the American Physical Society 2024

Interplay Between Intracellular Transport Dynamics and Liquid‒Liquid Phase Separation.

Liquid‒liquid phase separation (LLPS) is a ubiquitous process in which proteins, RNA, and biomolecules assemble into membrane-less compartments, playing important roles in many biological functions and diseases. The current knowledge on the biophysical and biochemical principles of LLPS is largely from in vitro studies; however, the physiological environment in living cells is complex and not at equilibrium. The characteristics of intracellular dynamics and their roles in physiological LLPS remain to be resolved. Here, by using single-particle tracking of quantum dots and dynamic monitoring of the formation of stress granules (SGs) in single cells, the spatiotemporal dynamics of intracellular transport in cells undergoing LLPS are quantified. It is shown that intracellular diffusion and active transport are both reduced. Furthermore, the formation of SG droplets contributes to increased spatial heterogeneity within the cell. More importantly, the study demonstrated that the LLPS of SGs can be regulated by intracellular dynamics in two stages: the reduced intracellular diffusion promotes SG assembly and the microtubule-associated transport facilitates SG coalescences. The work on intracellular dynamics not only improves the understanding of the mechanism of physiology phase separations occurring in nonequilibrium environments but also reveals an interplay between intracellular dynamics and LLPS.

General Synthesis of Composition-Tunable High-Entropy Amorphous Oxides Toward High Efficiency Oxygen Evolution Reaction.

High-entropy materials have attracted much attention in the electrocatalysis field due to their unique structure, high chemical activity, and compositional tunability. However, the harsh and complex synthetic methods limit the application of such materials. Herein, a universal non-equilibrium liquid-phase synthesis strategy is reported to prepare high-entropy amorphous oxide nanoparticles (HEAO-NPs), and the composition of HEAO-NPs can be precisely controlled from tri- to ten-component. The non-equilibrium synthesis environment provided by an excessively strong reducing agent overcomes the difference in the reduction potentials of various metal ions, resulting in the formation of HEAO-NPs with a nearly equimolar ratio. The oxygen evolution reaction (OER) performance of HEAO-NPs is further improved by adjusting the composition and optimizing the electronic structure. The Fe16Co32Ni32Mn10Cu10BOy exhibits a smaller overpotential (only 259mV at 10mAcm-2) and higher stability in OER compared with commercial RuO2. The amorphous high-entropy structure with an optimized concentration of iron makes the binding energy of CoNi shift to a higher direction, promotes the generation of high-valence active intermediates, and accelerates the OER kinetic process. The HEAO-NPs have promising application potential in the field of catalysis, biology, and energy storage, and this work provides a general synthesis method for composition-controllable high-entropy materials.

Recasting tenure and labour in non-equilibrium environments: Making the case for “high-reliability” pastoral institutions

This paper explores how pastoralists collectively manage resources in contexts of high environmental variability in the drylands of southern Tunisia. The khlata, the practice of pooling herds, allows for livestock owners to manage scarce resources in environments characterized by non-equilibrium dynamics. This institution legitimizes access to a wider range of pasture land thus tracking patchy rainfall distribution, and allows for the sharing of herding labour and so allows for “absence” in pastoral production, thus enabling human mobility. The khlata, recasts conceptualizations of tenure and labour in ways that subvert neoliberal models of production, and adapt to changing political economic conditions. Such collective herding practices can be likened to “high-reliability” management ideas that accommodate the social and networked dimensions of land-use in drylands, where coordination and connectivity through institutions becomes crucial. The theoretical approach includes pastoral perspectives on tenure, where rules are not well defined and membership is fluid, contributing to a different take on conventional common-property debates and neoliberal views on property, and indeed institutions. When pastoral production is framed as a high-reliability system, the objective of maintaining security and at the same time flexibility in land tenure is emphasised: livestock owners make use of a wide range of scale-dependent resources, whether public, private, or common property. Land-use policy should therefore focus not on rules and regulations but how to support institutions that maintain a highly-reliable system within contexts of fuzzy tenure regimes. Land-use policy should therefore focus on coordinating connectivity through collective arrangements by prioritizing the “informal” and adaptive nature of institutions such as the khlata, rather than focusing on their formalization. Overall, the paper shows how the khlata redefines access to land and labour in ways that create additional options for pastoralists to adapt to changing political economic conditions in southern Tunisia.

The effects of asymmetry in active noises on the efficiency of single colloidal Stirling engines with active noises.

Molecular machines, which operate in highly fluctuating environments far from equilibrium, may benefit from their non-equilibrium environments. It is, however, a topic of controversy how the efficiency of the microscopic engines can be enhanced. Recent experiments showed that microscopic Stirling engines in bacterial reservoirs could show high performance beyond the equilibrium thermodynamics. In this work, we perform overdamped Langevin dynamics simulations for microscopic Stirling heat engines in bacterial reservoirs and show that the temperature dependence of the magnitude of active noises should be responsible for such high efficiency. Only when we introduce temperature-dependent active noises, the efficiency of the microscopic Stirling engines is enhanced significantly as in experiments.

Microscopic origin of tunable assembly forces in chiral active environments.

Across a variety of spatial scales, from nanoscale biological systems to micron-scale colloidal systems, equilibrium self-assembly is entirely dictated by-and therefore limited by-the thermodynamic properties of the constituent materials. In contrast, nonequilibrium materials, such as self-propelled active matter, expand the possibilities for driving the assemblies that are inaccessible in equilibrium conditions. Recently, a number of works have suggested that active matter drives or accelerates self-organization, but the emergent interactions that arise between solutes immersed in actively driven environments are complex and poorly understood. Here, we analyze and resolve two crucial questions concerning actively driven self-assembly: (i) how, mechanistically, do active environments drive self-assembly of passive solutes? (ii) Under which conditions is this assembly robust? We employ the framework of odd hydrodynamics to theoretically explain numerical and experimental observations that chiral active matter, i.e., particles driven with a directional torque, produces robust and long-ranged assembly forces. Together, these developments constitute an important step towards a comprehensive theoretical framework for controlling self-assembly in nonequilibrium environments.

Mechanical property of the shape memorable Ti–Zr–Nb–Sn alloy manufactured by in-situ alloying in directed energy deposition

Ni-free β-type Ti alloys have been developed to manufacture high-strength, low-elastic-modulus, shape-memorable medical, and non-toxic components. Because the machinability of these alloys is generally poor, processing via additive manufacturing is an important step in the development of order-made medical devices. Although many studies evaluated the mechanical properties of additively manufactured Ni-free β-type Ti alloys, investigation of their heterogeneous microstructure resulting from the rapid melting-solidification cycling has not been discussed yet. In this study, the role of a heterogeneous microstructure on the performance of an in-situ alloyed Ti–Zr–Nb–Sn alloy was investigated. The metastable and nanosized ω phase, which is initiated in the non-equilibrium environment, enhances the yield strength without severe ductility degradation. Additionally, deformation-induced martensitic transformation occurs near the unmelted particle/matrix interface, and this phase transformation not only contributes to transformation-induced plasticity but also provides a superelasticity to the present alloy. Although the remained partially melted particle induces a localized corrosion in the matrix, the present results show that the heterogeneous microstructure of the in-situ alloyed Ti–Zr–Nb–Sn alloy exhibits outstanding mechanical properties and superelasticity, which will be suitable to fabricate biomedical parts via additive manufacturing.

Nonequilibrium Effects on the Precision of Parameter Estimation

AbstractThe impact of nonequilibrium environment effects on the accuracy of quantum parameter estimation is investigated, and it is found that these effects can significantly affect estimation accuracy. Using an individual estimation strategy reveals that the nonequilibrium effects consistently enhance accuracy, regardless of the coupling strength between the probe and its environment. In contrast, weak memory effects undermine estimation accuracy. When employing a multi‐parameter simultaneous estimation strategy, it is observed that the nonequilibrium effects consistently improve the advantages of simultaneous estimation, as analyzed by the ratio of total variances between the two estimation scenarios. However, the memory effects on these advantages depend on the coupling strength between the qubit and the environment. These findings suggest that appropriate parameters of a nonequilibrium environment can increase the quantum Fisher information (QFI), thereby enhancing the accuracy of quantum parameter estimation. These significant results are essential for improving parameter estimation accuracy in quantum systems interacting with nonequilibrium environments.

Inferring scale-dependent non-equilibrium activity using carbon nanotubes.

In living systems, irreversible, yet stochastic, molecular interactions form multiscale structures (such as cytoskeletal networks), which mediate processes (such as cytokinesis and cellular motility) in a close relationship between the structure and function. However, owing to a lack of methods to quantify non-equilibrium activity, their dynamics remain poorly characterized. Here, by measuring the time-reversal asymmetry encoded in the conformational dynamics of filamentous single-walled carbon nanotubes embedded in the actomyosin network of Xenopus egg extract, we characterize the multiscale dynamics of non-equilibrium activity encoded in bending-mode amplitudes. Our method is sensitive to distinct perturbations to the actomyosin network and the concentration ratio of adenosine triphosphate to adenosine diphosphate. Thus, our method can dissect the functional coupling of microscopic dynamics to the emergence of larger scale non-equilibrium activity. We relate the spatiotemporal scales of non-equilibrium activity to the key physical parameters of a semiflexible filament embedded in a non-equilibrium viscoelastic environment. Our analysis provides a general tool to characterize steady-state non-equilibrium activity in high-dimensional spaces.

Phase coexistence implications of violating Newton's third law.

Newton's third law, action = reaction, is a foundational statement of classical mechanics. However, in natural and living systems, this law appears to be routinely violated for constituents interacting in a nonequilibrium environment. Here, we use computer simulations to explore the macroscopic phase behavior implications of breaking microscopic interaction reciprocity for a simple model system. We consider a binary mixture of attractive particles and introduce a parameter that is a continuous measure of the degree to which interaction reciprocity is broken. In the reciprocal limit, the species are indistinguishable, and the system phase separates into domains with distinct densities and identical compositions. Increasing nonreciprocity is found to drive the system to explore a rich assortment of phases, including phases with strong composition asymmetries and three-phase coexistence. Many of the states induced by these forces, including traveling crystals and liquids, have no equilibrium analogs. By mapping the complete phase diagram for this model system and characterizing these unique phases, our findings offer a concrete path forward toward understanding how nonreciprocity shapes the structures found in living systems and how this might be leveraged in the design of synthetic materials.

Effects of active noise on transition-path dynamics

We propose an extension of the existing model describing a biomolecular reaction such as protein folding or ligand binding which is usually visualised as the barrier crossing of a diffusing particle in a double-well potential. In addition to the thermal noise, an active noise modelled in terms of an Ornstein–Uhlenbeck process is introduced to the dynamics. Within this framework, we investigate the transition-path properties of an underdamped particle surmounting an energy barrier, and we show explicitly how these properties are affected by the activity and persistence of the particle. Our theoretical study suggests that an active particle can cross the barrier at comparatively shorter timescales by lowering the (effective) barrier height. In particular, we study how the persistence time of the active force alters the transition-path time (TPT) at different friction limits. Interestingly, in one of our models we find a nonmonotonic behaviour of the TPT which is absent in the overdamped limit. The framework presented here can be useful in designing a reaction in a non-equilibrium environment, particularly inside a living biological cell in which active fluctuations keep the system out of equilibrium.

Continuous-variable polarization mode entanglement in a V-type micromaser

The micromaser is an archetype experimental setting where a beam of excited two-level atoms is injected into a high-finesse cavity. It has played a pivotal role as a testbed for predictions of quantum optics. We consider a generalized micromaser setting consisting of a high-quality cavity pumped by a beam of three-level atoms. The atoms are assumed to be prepared to carry quantum coherence between their excited state doublet. Our objective is to produce quantum entanglement between the right-handed circular (RHC) and left-handed circular (LHC) polarized photons in the cavity, exploiting the quantum coherence in the pump atoms. For that aim, we derive the generalized micromaser master equation for our system. We find that the dynamics of the micromaser field driven by the pump beam is equivalent to two non-interacting RHC and LHC photonic systems sharing a common non-equilibrium environment. The effect of the shared bath is to mediate an incoherent interaction between the otherwise non-interacting cavity photons, which emerges only if the atoms carry quantum coherence. We take into account cavity losses as a source of quantum decoherence and characterize the quantum entanglement between the LHC and RHC polarized photons in terms of logarithmic negativity, Hillery–Zubairy and spin squeezing criterion, calculated using the dynamical solution of the master equation. We show that, in the same parameter regime, one of the criteria shows entanglement while for the other never detects entanglement. Our results reveal that LHC and RHC polarized photons can be entangled in the transient regime according to the logarithmic negativity criterion.

Uncertainty and information causality in opportunity-as-artefact driving entrepreneurial actions

PurposeEntrepreneurs prioritise and act on purposeful endeavours instigated to actions by the visions of profits and benefits in the perceived opportunities. In the state of maximum entropy, with disorderliness and disequilibrium, entrepreneurs select the preferred pathway, through the profit-sensing mechanism, with the best probability of success to bet on. Therefore, this paper unpacks the forces at work in the mechanism to explain how entrepreneurs respond to opportunity and interpret the signals to coalesce into organised actions.Design/methodology/approachThis research is primarily a conceptual paper on entrepreneurial action and the mechanism leading to that action. It refers to thermodynamic principles and biological cases to explain the forces at work using mostly analogical comparisons and similarities.FindingsThis paper aims to present an alternative theoretical scaffolding for entrepreneurship researchers to explore non-rational entrepreneurial behaviours and actions in uncertain, unstable and non-equilibrium environments, thereby creating new and competing hypotheses under the backdrop of adaptive evolution and thermodynamics phenomena.Research limitations/implicationsThe discussion featuring instinctively and naturally forming responses cannot fully explain the real entrepreneurial action as there is an element of free will and choices that are not discussed. While strategic choice and free-will shape decisions, they are preceded first by the attraction of the gradients and the biased motion in the direction of profit-attractant.Practical implicationsThere remain essential links and issues not addressed in this “natural science”, constituting life science and physical science, oriented entrepreneurship research and exploration. Conceptualising opportunity-as-artefact and entrepreneurship as design, significant incidences of entrepreneurial actions can be explained by the presence of gradients stimulating entrepreneurial actions.Social implicationsThis viewpoint of information causality in opportunity-as-artefact casts a new look at the venerable question of what causes entrepreneurial actions. Shane and Venkataraman brought into focus this conversation, initiating the conceptual definition of opportunity. To have entrepreneurship, entrepreneurial opportunities must come first. Figuring the signals arising from these opportunities and cueing entrepreneurs to action is the main focus of this study.Originality/valueConsidering the “mechanism” at work and the thermodynamical forces at play, the entrepreneurial design process appears to hold considerable promise for future research development.

Periodic potential can enormously boost free-particle transport induced by active fluctuations.

Active fluctuations are detected in a growing number of systems due to self-propulsion mechanisms or collisions with an active environment. They drive the system far from equilibrium and can induce phenomena that are forbidden at equilibrium states by, e.g., fluctuation-dissipation relations and detailed balance symmetry. Understanding their role in living matter is emerging as a challenge for physics. Here we demonstrate a paradoxical effect in which a free-particle transport induced by active fluctuations can be boosted by many orders of magnitude when the particle is additionally subjected to a periodic potential. In contrast, within the realm of only thermal fluctuations, the velocity of a free particle exposed to a bias is reduced when the periodic potential is switched on. The presented mechanism is significant for understanding nonequilibrium environments such as living cells, where it can explain from a fundamental point of view why spatially periodic structures known as microtubules are necessary to generate impressively effective intracellular transport. Our findings can be readily corroborated experimentally, e.g., in a setup comprising a colloidal particle in an optically generated periodic potential.

Quantum State Tomography in Nonequilibrium Environments

We generalize an approach to studying the quantum state tomography (QST) of open systems in terms of the dynamical map in Kraus representation within the framework of dynamic generation of informationally complete positive operator-valued measures. As applications, we use the generalized approach to theoretically study the QST of qubit systems in the presence of nonequilibrium environments which exhibit nonstationary and non-Markovian random telegraph noise statistical properties. We derive the time-dependent measurement operators for the quantum state reconstruction of the single qubit and two-qubit systems in terms of the polarization operator basis. It is shown that the behavior of the time-dependent measurement operators is closely associated with the dynamical map of the qubit systems.

Formation of dissipative structures in microscopic models of mixtures with species interconversion

The separation of substances into different phases is ubiquitous in nature and important scientifically and technologically. This phenomenon may become drastically different if the species involved, whether molecules or supramolecular assemblies, interconvert. In the presence of an external force large enough to overcome energetic differences between the interconvertible species (forced interconversion), the two alternative species will be present in equal amounts, and the striking phenomenon of steady-state, restricted phase separation into mesoscales is observed. Such microphase separation is one of the simplest examples of dissipative structures in condensed matter. In this work, we investigate the formation of such mesoscale steady-state structures through Monte Carlo and molecular dynamics simulations of three physically distinct microscopic models of binary mixtures that exhibit both equilibrium (natural) interconversion and a nonequilibrium source of forced interconversion. We show that this source can be introduced through an internal imbalance of intermolecular forces or an external flux of energy that promotes molecular interconversion, possible manifestations of which could include the internal nonequilibrium environment of living cells or a flux of photons. The main trends and observations from the simulations are well captured by a nonequilibrium thermodynamic theory of phase transitions affected by interconversion. We show how a nonequilibrium bicontinuous microemulsion or a spatially modulated state may be generated depending on the interplay between diffusion, natural interconversion, and forced interconversion.

Xenon in the Protoplanetary Disk (PPD), in Two Planets, and a Comet

Isotopic anomalies in several elements, as recently observed in meteorites, are generally interpreted to indicate nonequilibrium environments in the protoplanetary disk (PPD). Here we study reported Xe isotopic compositions on planets Earth and Mars, in a comet, and in meteorites for precursor discrepancies. Abundance variations of inferred presolar nano-diamonds, the carrier phase of the Xe-HL component, appear to be the primary source of nonuniformity of Xe precursors in the PPD, together with mechanisms of mass-dependent fractionation. While planet Mars kept a record of initial solar Xe isotopic abundances, such a record is missing for planet Earth. Xe isotopic abundances in paleo-atmospheres of both planets represent secondary reservoirs that show mass-dependent fractionation effects, but the inferred compositions of their PPD precursors differ: Mars atmospheric precursor Xe had solar isotopic composition, while Earth’s Xe precursor is consistent with a PPD reservoir of low nano-diamond abundance. Strong mass-dependent fractionation effects are observed in Xe components of IAB irons and in Yamato carbonaceous (CY) chondrites, and show that fractionation mechanisms are not restricted to planetary atmospheres. These records show that Xe isotopes in solar system reservoirs are useful tracers of evolutionary processes and of nonequilibrated presolar components in the PPD.