Nonequilibrium Open System Research Articles

Numerical simulations of complex nonequilibrium flows in finite regions on the basis of the Boltzmann kinetic equation

A new formulation of the inner boundary problem for description complex nonequilibrium flows between membranes is presented. Solutions by means of the Boltzmann equation and the model kinetic equation for mixtures with chemical reactions demonstrate interesting physical properties in this open nonequilibrium system. Possibility of the anomalous thermal transport where the heat flux and the temperature gradient are of the same sign, is studied. Influence of boundary conditions on the parameters of the structure is considered as well.

Topological unification of time-reversal and particle-hole symmetries in non-Hermitian physics

Topological phases are enriched in non-equilibrium open systems effectively described by non-Hermitian Hamiltonians. While several properties unique to non-Hermitian topological systems were uncovered, the fundamental role of symmetry in non-Hermitian physics has yet to be fully understood, and it has remained unclear how symmetry protects non-Hermitian topological phases. Here we show that two fundamental anti-unitary symmetries, time-reversal and particle-hole symmetries, are topologically equivalent in the complex energy plane and hence unified in non-Hermitian physics. A striking consequence of this symmetry unification is the emergence of unique non-equilibrium topological phases that have no counterparts in Hermitian systems. We illustrate this by presenting a non-Hermitian counterpart of the Majorana chain in an insulator with time-reversal symmetry and that of the quantum spin Hall insulator in a superconductor with particle-hole symmetry. Our work establishes a fundamental symmetry principle in non-Hermitian physics and paves the way towards a unified framework for non-equilibrium topological phases.

Measuring Dissipation of Molecular Motor Kinesin

Molecular motors are nonequilibrium open systems that convert chemical energy to mechanical work. The nonequilibrium energetics of single molecule kinesin were investigated by measuring the motion of an attached probe particle and its response to external forces with optical tweezers. The sum of the heat dissipation estimated from the violation of the fluctuation-response relation and the output power was inconsistent with the input free energy rate, indicating that large internal dissipation exists. Here we introduce the theoretical basis of the dissipation measurement and our recent experimental results, discussing the physiological implications of the hidden dissipation in the kinesin motor.

Study of cytoskeletal structures in cells under nonequilibrium open system

Study of cytoskeletal structures in cells under nonequilibrium open system

Determinism in Physics and Cognoscibility of a Picture of the World

The purpose of the article is to show the key role of the deterministic mechanism of irreversibility (DMI) in the understanding of the picture of the world and in its construction. For this, a brief analysis of the historical development of the picture of the world and the tasks of its further development, connected with the problems of describing the processes of evolution in the framework of the laws of fundamental physics, has been carried out. It is shown how DMI removes these problems. The role of DMI in the statement of the principle of causality in physics is studied. It is shown how DMI contributes to the realization of the ideas of universal evolutionism. It also shows how the conclusion that the open non-equilibrium dynamic system should be an element of matter and why matter should be a hierarchy of such systems follows from the condition of DMI existence. Using the example of the relationship between the laws of the evolution of systems and the laws of the dynamics of their elements, it is demonstrated how the law of transition of quantity to quality is implemented in physics and how one can build a picture of the world from simplicity to complexity. It is shown how with the help of numerical methods possible to substantiate that the laws of thermodynamics, statistical physics follow from the fundamental laws of nature.

Metals Property Changes Under Effect of Vacancy-Cluster Structures

The experimental results analysis of a metals property changes under vacancy-cluster structure effects are shown. Two technological approaches of such structures obtaining are considered. The first is a nanopowders compaction under high (up to 5GPa) hydrostatic compression, on example of a Ni nanopowder (70nm). The second is the Al and Pb crystallization under the high-intensity plastic deformation [e¢ = (102-104) sec-1] (НIPD) conditions on the solid-liquid boundary in the centrifugal casting machine with rotary speed up to 2000 rpm. Using the method of atomic force microscopy (AFM), vacancy cluster tubes (VCT) with average diameters of 39 nm for Al and 25 nm for Pb have been detected in the crystallized volume of Al and Pb metals. Discussed the physical model of a new substructure formation within the metals in the form of vacancy cluster tubes, obtained in the process of high-intensive plastic deformation (HIPD) during the process of mass crystallization of Al and Pb and the changes in the mechanical, magnetic and superconducting properties of the above metals, which followed this process. During Al and Pb crystallization under high-intensive plastic deformation (HIPD) range about [e′ = (102–104) sec-1] with specially selected modes of metals crystallization in high-speed centrifugal casting machine the special conditions are being created to achieve the dimensional effect of dynamic (shifting) re-crystallization. Shifting deformation during centrifugal crystallization caused primarily by a large incline of the temperature field from the periphery (relative to the cold wall of the rotor) to the molten central part of the rotor. The difference in the angular velocities of the already-frozen part of the metal (adjacent to the outer surface of the rotor wall) and the central part, where the metal still remains in the molten state, leads to a high-intensity deformation [e′ = (102–104) sec-1] of the crystallized metal melt solidified phase. Since the grain sizes at the crystallized phase initially comprise around tens of nano-meters (approximately crystal nucleation size), it becomes possible to achieve the dimensional effect of the dynamic re-crystallization of a «nanocrystalline» solidified metal at high shift of strain velocities. The ≪non-equilibrium vacancies≫ formed this way condense into vacancy clusters, which are formed in the centrifugal force field in the form of vacancy-shaped cluster tubes stretched out to the center of rotation of the rotor. The process proceeds under conditions far from the equilibrium in comparison with the usual crystallization of the metal from the melt. Such processes can lead to the formation of highly ordered non-equilibrium statescharacteristic of non-equilibrium open systems. Discussed the physical model of a metals vacancy-cluster structures formation at high hydrostatic nanopowders compression (up to 5 GPa) and high-intensity plastic deformation (HIPD) at the stage of Al and Pb alloys mass crystallization during centrifugation. Conclusion of the article is that the high-intensity plastic deformation (НIPD) at the melt crystallization stage against a background of high stationary nonequilibrium vacancies concentration brings to the new type of the elements structure formation - vacancy cluster tubes (VCT). A comparative analysis of mechanical, magnetic and superconducting properties changes for structured metals introduced.

EVALUATION OF EXPLOSIVE RISK IN THE PROCESS STORAGE OF WELDED NUCLEAR FUEL

EVALUATION OF EXPLOSIVE RISK IN THE PROCESS STORAGE OF WELDED NUCLEAR FUEL

On structural and phase transitions in aluminum alloys

Mathematical modelling of behavior of group of the industrial aluminum alloys with initial varying grain size structure showing superplastic properties in certain temperature and strain rate ranges is presented. It is known that the structural superplasticity is connected with facilitated by fine-grained structure formation (1…10 microns) at the preliminary stage. However, for realization of superplasticity of “dynamic type” there has to be a replacement of an initial varying grain size structure state of material with another, ready for superplasticity. Therefore the used definition “the dynamic superplasticity” reflects consecutive change of states which happens in material with initial varying grain size structure under the changing temperature-rate conditions: initial varying grain size → equiaxed fine-grained structure (4…7 microns) formed under the temperature-rate conditions of superplasticity → coarse-grained at further increase in strain rate. These changes are caused by simultaneous action of deformation rates and structural (phase) transitions of evolutionary type in open nonequilibrium systems. In particular, for the considered commercial aluminum alloys with initial varying grain size structure such irreversible transition is dynamic recrystallization. The association of deformation process with metal flow that has irreversible structural and phase transition of indistinct type at one of the stages, allows using synergetic approach. The mathematical model formulated from positions of solid mechanics use allow to research nonequilibrium system reaction to behavior of thermodynamic response functions – the specific heat and entropy – and to establish implementations features of the irreversible indistinct phase transitions observed in the conditions of dynamic superplasticity for aluminum alloys.

On Dynamic Superplasticity of Aluminum Alloys with Initial Varying Grain Size Structure

In the submitted paper there is a speech about mathematical modeling of behavior of group of the industrial aluminum alloys with initial varying grain size structure showing superplastic properties in certain temperature and strain rate ranges. Superplasticity of dynamic type are caused by simultaneous action of deformation rates and structural (phase) transitions of evolutionary type in open nonequilibrium systems. The association of deformation process with metal flow, that has irreversible structural and phase transition of indistinct type at one of the stages, allows to use synergetic approach. The experimental study of deformation behavior of group commercial aluminum alloys with initial varying grain size structure in the wide temperature and strain rate ranges (not only in case of superplasticity, but also in the boundary fields of thermoplasticity and high-temperature creep.) has led to creation of the mathematical model formulated from positions of mechanics of solid for simple tensile and compression. At the same time the offered model contains analytically formulated conditions for transition of material to a superplastic state. With using of the theory of elasto-plastic processes of small curvature the developed mathematical model is generalized for combined stress for technological problems of volume forming with use of superplasticity for the purpose receiving a semi-finished product with fine-grained structure.

PRINCIPLES OF SUSTAINABLE SPATIAL NONEQUILIBRIUM

<p>On the basis of ongoing research and development the authors substantiate the need to improve the theoretical and methodological foundations of self-development processes for equilibrium and non-equilibrium economic multi-level systems.Particular attention is paid to the analysis of the functioning of the so-called «microscopic open nonequilibrium systems»</p><p>In the article, the economic system is viewed from the point of view of synergy - as dual entities consisting of a continuous and discrete sphere.Classification of possible evolutionary changes in the kinetic and constitutional spheres in the process of self-development for economic equilibrium and nonequilibrium systems.Particular attention is paid to the continuous self-organization of microscopic open systems.</p>

PRINCIPLES OF SUSTAINABLE SPATIAL NONEQUILIBRIUM

<p>On the basis of ongoing research and development the authors substantiate the need to improve the theoretical and methodological foundations of self-development processes for equilibrium and non-equilibrium economic multi-level systems.Particular attention is paid to the analysis of the functioning of the so-called «microscopic open nonequilibrium systems»</p><p>In the article, the economic system is viewed from the point of view of synergy - as dual entities consisting of a continuous and discrete sphere.Classification of possible evolutionary changes in the kinetic and constitutional spheres in the process of self-development for economic equilibrium and nonequilibrium systems.Particular attention is paid to the continuous self-organization of microscopic open systems.</p>

ОСОБЕННОСТИ СТРУКТУРИРОВАНИЯ ПРИ МАССОВОЙ КРИСТАЛЛИЗАЦИИ РАСПЛАВОВ Al И Pb В УСЛОВИЯХ ВЫСОКОИНТЕНСИВНОЙ ПЛАСТИЧЕСКОЙ ДЕФОРМАЦИИ ПРИ ЦЕНТРИФУГИРОВАНИИ

Представлены экспериментальные результаты по кристаллизации Al и Pb в условиях высокоинтенсивной пластической деформации [e¢ = (102-104) сек-1] на границе раздела «твердое-жидкое» в аппарате центробежного литья нового типа при скоростях вращения ротора до 2000 об/мин. В объёме закристаллизованных металлов Al и Pb методом атомной силовой микроскопии обнаружены вакансионные кластерные трубки со средними диаметрами Al – 39 нм, Pb – 25 нм. Обсуждается физическая модель образования в металлах новой субструктуры в виде вакансионных кластерных трубок, полученных при высокоинтенсивной пластической деформации.

Lindblad formalism based on fermion-to-qubit mapping for nonequilibrium open quantum systems

We present an alternative form of master equation, applicable on the analysis of non-equilibrium dynamics of fermionic open quantum systems. The formalism considers a general scenario, composed by a multipartite quantum system in contact with several reservoirs, each one with a specific chemical potential and in thermal equilibrium. With the help of Jordan-Wigner transformation, we perform a fermion-to-qubit mapping to derive a set of Lindblad superoperators that can be straightforwardly used on a wide range of physical setups.To illustrate our approach, we explore the effect of a charge sensor, acting as a probe, over the dynamics of electrons on coupled quantum molecules. The probe consists on a quantum dot attached to source and drain leads, that allows a current flow. The dynamics of populations, entanglement degree and purity show how the probe is behind the sudden deaths and rebirths of entanglement, at short times. Then, the evolution leads the system to an asymptotic state being a statistical mixture. Those are signatures that the probe induces dephasing, a process that destroys the coherence of the quantum system.

Aqueous solutions of humic acids as self-organizing dissipative systems

The paper investigates the size, morphology and ζ-potential of particles, electrical conduction, and surface tension of aqueous solutions of humic acids as a function of their concentration, pH and time using the methods of dynamic and electrophoretic light scattering, transmission electron microscopy and tensiometry. It is shown that aqueous solutions of humic acids represent open non-equilibrium systems with complex multilevel space-time self-organization. The critical concentrations reflecting the transition from one state into another have been also established.

Proposed Empirical Entropy and Gibbs Energy Based on Observations of Scale Invariance in Open Nonequilibrium Systems.

There is no widely agreed definition of entropy, and consequently Gibbs energy, in open systems far from equilibrium. One recent approach has sought to formulate an entropy and Gibbs energy based on observed scale invariances in geophysical variables, particularly in atmospheric quantities, including the molecules constituting stratospheric chemistry. The Hamiltonian flux dynamics of energy in macroscopic open nonequilibrium systems maps to energy in equilibrium statistical thermodynamics, and corresponding equivalences of scale invariant variables with other relevant statistical mechanical variables such as entropy, Gibbs energy, and 1/(kBoltzmannT), are not just formally analogous but are also mappings. Three proof-of-concept representative examples from available adequate stratospheric chemistry observations-temperature, wind speed and ozone-are calculated, with the aim of applying these mappings and equivalences. Potential applications of the approach to scale invariant observations from the literature, involving scales from molecular through laboratory to astronomical, are considered. Theoretical support for the approach from the literature is discussed.

Efficient steady-state solver for hierarchical quantum master equations.

Steady states play pivotal roles in many equilibrium and non-equilibrium open system studies. Their accurate evaluations call for exact theories with rigorous treatment of system-bath interactions. Therein, the hierarchical equations-of-motion (HEOM) formalism is a nonperturbative and non-Markovian quantum dissipation theory, which can faithfully describe the dissipative dynamics and nonlinear response of open systems. Nevertheless, solving the steady states of open quantum systems via HEOM is often a challenging task, due to the vast number of dynamical quantities involved. In this work, we propose a self-consistent iteration approach that quickly solves the HEOM steady states. We demonstrate its high efficiency with accurate and fast evaluations of low-temperature thermal equilibrium of a model Fenna-Matthews-Olson pigment-protein complex. Numerically exact evaluation of thermal equilibrium Rényi entropies and stationary emission line shapes is presented with detailed discussion.

Anomalous heat transfer for an open non-equilibrium gaseous system

The steady state of an open non-equilibrium one-dimensional system is considered using the linearized kinetic Bhatnagar–Gross–Krook (BGK) model. It is shown that the BGK model has a stationary distribution function describing a gas for which the heat flow and the temperature gradient has the same sign—heat is transferred from cold regions to hotter regions. This distribution function cannot be presented in the form of a truncated Grad expansion. A numerical study of a boundary problem with non-equilibrium special boundary conditions supports the theoretical predictions.

Dicke phase transition without total spin conservation

We develop a new fermionic path-integral formalism to analyze the phase diagram of open nonequilibrium systems. The formalism is applied to analyze an ensemble of two-level atoms interacting with a single-mode optical cavity, described by the Dicke model. While this model is often used as the paradigmatic example of a phase transition in driven-dissipative systems, earlier theoretical studies were limited to the special case when the total spin of the atomic ensemble is conserved. This assumption is not justified in most experimental realizations. Our new approach allows us to analyze the problem in a more general case, including the experimentally relevant case of dissipative processes that act on each atom individually and do not conserve the total spin. We obtain a general expression for the position of the transition, which contains as special cases the two previously known regimes: i) non-equilibrium systems with losses and conserved spin and ii) closed systems in thermal equilibrium and with the Gibbs ensemble averaging over the values of the total spin. We perform a detailed study of different types of baths and point out the possibility of a surprising non-monotonous dependence of the transition on the baths' parameters.

Thermodynamic meaning of local temperature of nonequilibrium open quantum systems

Measuring the local temperature of nanoscale systems out of equilibrium has emerged as a new tool to study local heating effects and other local thermal properties of systems driven by external fields. Although various experimental protocols and theoretical definitions have been proposed to determine the local temperature, the thermodynamic meaning of the measured or defined quantities remains unclear. By performing analytical and numerical analysis of bias-driven quantum dot systems both in the noninteracting and strongly-correlated regimes, we elucidate the underlying physical meaning of local temperature as determined by two definitions: the zero-current condition that is widely used but not measurable, and the minimal-perturbation condition that is experimentally realizable. We show that, unlike the zero-current one, the local temperature determined by the minimalperturbation protocol establishes a quantitative correspondence between the nonequilibrium system of interest and a reference equilibrium system, provided the probed system observable and the related electronic excitations are fully local. The quantitative correspondence thus allows the well-established thermodynamic concept to be extended to nonequilibrium situations.

On the Dynamic Superplasticity

Superplasticity is considered as a special state of the polycrystalline material plastically deformed at the low level of the stress with the retaining of the ultrafine-grained structure – structural superplasticity received at the previous stage or arised during hot deformation independently from the initial grain size – dynamic superplasticity. For realization of the dynamic superplasticity it has to substitute an initial structural condition of material another, allowed to realize a superplasticity. The mentioned above changes are caused by the conforms of the proper strain rates and structural (phase) transformations of the evolutionary type in the open nonequilibrium systems. It is proposed an approach applying to the modelling of the deformation processes at the superplastic flow of commercial aluminum alloys taking into account the boundary regions in the framework the theory of self-organization of dissipative structures. An examples of the theoretical and experimental data correlation are given.