Photon waiting time distributions: a keyhole into dissipative quantum chaos

Open quantum systems can exhibit complex states, which classification and quantification is still not well resolved. The Kerr-nonlinear cavity, periodically modulated in time by coherent pumping of the intra-cavity photonic mode, is one of the examples. Unraveling the corresponding Markovian master equation into an ensemble of quantum trajectories and employing the recently proposed calculation of quantum Lyapunov exponents [I.I. Yusipov {\it et al.}, Chaos {\bf 29}, 063130 (2019)], we identify `chaotic' and `regular' regimes there. In particular, we show that chaotic regimes manifest an intermediate power-law asymptotics in the distribution of photon waiting times. This distribution can be retrieved by monitoring photon emission with a single-photon detector, so that chaotic and regular states can be discriminated without disturbing the intra-cavity dynamics.Comment: 7 pages, 5 figure

Control of a single-particle localization in open quantum systems

We investigate the possibility to control localization properties of the asymptotic state of an open quantum system with a tunable synthetic dissipation. The control mechanism relies on the matching between properties of dissipative operators, acting on neighboring sites and specified by a single control parameter, and the spatial phase structure of eigenstates of the system Hamiltonian. As a result, the latter coincide (or near coincide) with the dark states of the operators. In a disorder-free Hamiltonian with a flat band, one can either obtain a localized asymptotic state or populate whole flat and/or dispersive bands, depending on the value of the control parameter. In a disordered Anderson system, the asymptotic state can be localized anywhere in the spectrum of the Hamiltonian. The dissipative control is robust with respect to an additional local dephasing.Comment: 6 pages, 5 figure

Localization in open quantum systems

In an isolated single-particle quantum system a spatial disorder can induce Anderson localization. Being a result of interference, this phenomenon is expected to be fragile in the face of dissipation. Here we show that dissipation can drive a disordered system into a steady state with tunable localization properties. This can be achieved with a set of identical dissipative operators, each one acting non-trivially only on a pair of neighboring sites. Operators are parametrized by a uniform phase, which controls selection of Anderson modes contributing to the state. On the microscopic level, quantum trajectories of a system in a localized steady regime exhibit intermittent dynamics consisting of long-time sticking events near selected modes interrupted by jumps between them.Comment: 5 pages, 5 figure

Implementation of electronic business interaction in terms of mental characteristics of business partners

Vorobyova, A. E. Implementation of electronic business interaction in terms of mental characteristics of business partners / A. E. Vorobyova, M. I. Vershinina // Научный результат. Сер. Вопросы теоретической и прикладной лингвистики. - 2019. – Т.5, №4.-С 3-9. - Doi: 10.18413/2313-8912-2019-5-4-0-1.The present study is aimed at revealing different approaches to discourse styles and rhetoric conventions of intercultural business communication that are inherent in mentality of representatives of dif. ferent linguistic and cultural communities. For this purpose, the so called “Hamburger model” was extrapolate

Localization in periodically modulated speckle potentials

Disorder in a 1D quantum lattice induces Anderson localization of the eigenstates and drastically alters transport properties of the lattice. In the original Anderson model, the addition of a periodic driving increases, in a certain range of the driving's frequency and amplitude, localization length of the appearing Floquet eigenstates. We go beyond the uncorrelated disorder case and address the experimentally relevant situation when spatial correlations are present in the lattice potential. Their presence induces the creation of an effective mobility edge in the energy spectrum of the system. We find that a slow driving leads to resonant hybridization of the Floquet states, by increasing both the participation numbers and effective widths of the states in the strongly localized band and decreasing values of these characteristics for the states in the quasi-extended band. Strong driving homogenizes the bands, so that the Floquet states loose compactness and tend to be spatially smeared. In the basis of the stationary Hamiltonian, these states retain localization in terms of participation number but become de-localized and spectrum-wide in term of their effective widths. Signatures of thermalization are also observed.Comment: 6 pages, 3 figure

Lyapunov exponents of quantum trajectories beyond continuous measurements

Quantum systems interacting with their environments can exhibit complex non-equilibrium states that are tempting to be interpreted as quantum analogs of chaotic attractors. Yet, despite many attempts, the toolbox for quantifying dissipative quantum chaos remains very limited. In particular, quantum generalizations of Lyapunov exponent, the main quantifier of classical chaos, are established only within the framework of continuous measurements. We propose an alternative generalization which is based on the unraveling of a quantum master equation into an ensemble of so-called 'quantum jump' trajectories. These trajectories are not only a theoretical tool but a part of the experimental reality in the case of quantum optics. We illustrate the idea by using a periodically modulated open quantum dimer and uncover the transition to quantum chaos matched by the period-doubling route in the classical limit.Comment: 5 pages, 4 figure

Addressing the needs of international students: a case from a russian university

Introduction The study addresses the needs of university educators in alternative, more efficient teaching techniques supported by the psychological approach.Method The introduced method of fairy tale writing, based on the potential of Russian traditional fairy tales, encourages critical thinking, and enhances the problem solving process in the context of international students’ identification with an imaginary personality. The defense mechanisms unconsciously applied in the frame of an individual’s narration assist in interpreting their emotional state and psychological adaptation levels at a certain point in time.Results The complexity of the adjustment process should be scrupulously considered, as the nature of individually applied defense mechanisms is dependent on the culture and contextually relevant. Fairy tale therapy gives international students a chance to negotiate identity in writing and acquire positive feelings of attachment and belonging. Instructors benefit from “hearing out” and learning about the students who, in the traditional educational setting, would reveal shyness associated with some cultural predisposition (China, Japan, and Korea).Discussion The timely changed class instruction style and more person-centered approach can modify the situational adaptation outcomes, and long-duration observation can provide aclearer picture of identity transition. Arrangements should be made to adequately shift emotional discontent at the critical point, and this is a task for both the local university administration and the national legislative body. The theoretical prerequisite of universalism of human emotions enables the educators to perceive the coded message in the narrators’ ‘voices’ and become mediators between international students and university administration.Keywords: defense mechanisms, emotional state, psychological adaptation, Russian fairy tales, universal semantic primitive

The effect of alloying on the microstructure and mechanical properties of Mo-Fe-B boride hard alloys

Mo2FeB2 based cermets with different Cr and Ni contents were prepared by liquid phase sintering. The effects of Ni and Cr content on the microstructure, hardness and fracture toughness were investigated. The results reveal that alloying of cermet with nickel leads to formation of structure сharacterized by high austenite volume fraction and low ferrite conten

Disentangling age-dependent DNA methylation: deterministic, stochastic, and nonlinear

DNA methylation variability arises due to concurrent genetic and environmental influences. Each of them is a mixture of regular and noisy sources, whose relative contribution has not been satisfactorily understood yet. We conduct a systematic assessment of the age-dependent methylation by the signal-to-noise ratio and identify a wealth of "deterministic" CpG probes (about 90%), whose methylation variability likely originates due to genetic and general environmental factors. The remaining 10% of "stochastic" CpG probes are arguably governed by the biological noise or incidental environmental factors. Investigating the mathematical functional relationship between methylation levels and variability, we find that in about 90% of the age-associated differentially methylated positions, the variability changes as the square of the methylation level, whereas in the most of the remaining cases the dependence is linear. Furthermore, we demonstrate that the methylation level itself in more than 15% cases varies nonlinearly with age (according to the power law), in contrast to the previously assumed linear changes. Our findings present ample evidence of the ubiquity of strong DNA methylation regulation, resulting in the individual age-dependent and nonlinear methylation trajectories, whose divergence explains the cross-sectional variability. It may also serve a basis for constructing novel nonlinear epigenetic clocks

Biosynthesis of secreted ribonucleases of Bacillus intermedius and Bacillus circulans under nitrogen starvation

The level of biosynthesis of secreted guanyl-specific ribonucleases (RNases) of Bacillus intermedius (binases) and Bacillus circulans (RNases Bci) by recombinant B. subtilis strains increases under nitrogen starvation. The promoter of the binase gene carries the sequences homologous to the recognition sites of the regulatory protein TnrA, which regulates gene expression under growth limitation by nitrogen. Using the B. subtilis strain defective in protein TnrA, it has been shown that the regulatory protein TnrA is involved in the regulation of expression of the binase gene and the gene of RNase Bci. The TnrA regulation of expression of the RNase Bci gene is indirect, probably by means of the regulatory protein PucR. Thus, it has been established that at least two regulatory mechanisms activate the expression of the genes encoding the secreted RNases of spore-forming bacteria: a system of proteins homologous to the B. subtilis PhoP-PhoR, and regulation by a protein similar to the B. subtilis TnrA regulatory protein. © 2009 Pleiades Publishing, Ltd