140 research outputs found
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 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
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
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
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 Ρharacterized by high austenite volume fraction and low ferrite conten
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. Β© 2009 Pleiades Publishing, Ltd
Respiratory pathology in connective tissue dysplasia (Irterture review)
This article represents the literature review devoted to a problem of a respiratory pathology at heritable disorders of connective tissue. Historical aspects of the concept connective tissue dysplasia are given, the basic terminological and classification approaches including debatable are presented. General data about the lungs pathology at monogene genetic syndromes is cited. Results of researches on which basis diagnostic criteria of respiratory pathology have been allocated at widespread undifferentiated variants of a heritable disorders of connective tissue are analysed. It is shown that the condition of respiratory organs at a connective tissue dysplasia is defined morphofunctional changes of respiratory tracts and a pulmonary parenchyma and influence of various extrapulmonary factors. It is noticed that the majority of works has mainly descriptive character without attempt of carrying out of fundamental morphological and pathophysiological researches which would allow to explain respiratory pathology mechanisms.ΠΠ°Π½Π½Π°Ρ ΡΡΠ°ΡΡΡ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΠ΅Ρ ΡΠΎΠ±ΠΎΠΉ ΠΎΠ±Π·ΠΎΡ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΡ, ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π½ΠΎΠΉ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ΅ ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΡ ΠΎΡΠ³Π°Π½ΠΎΠ² Π΄ΡΡ
Π°Π½ΠΈΡ ΠΏΡΠΈ Π½Π°ΡΠ»Π΅Π΄ΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π°ΡΡΡΠ΅Π½ΠΈΡΡ
ΡΠΎΠ΅Π΄ΠΈΠ½ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ. ΠΡΠ²Π΅ΡΠ΅Π½Ρ ΠΈΡΡΠΎΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π°ΡΠΏΠ΅ΠΊΡΡ ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ Π΄ΠΈΡΠΏΠ»Π°Π·ΠΈΠΈ ΡΠΎΠ΅Π΄ΠΈΠ½ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ, ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅, Π² ΡΠΎΠΌ ΡΠΈΡΠ»Π΅ Π΄ΠΈΡΠΊΡΡΡΠΈΠΎΠ½Π½ΡΠ΅, ΡΠ΅ΡΠΌΠΈΠ½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΈ ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½ΡΠ΅ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Ρ. ΠΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅ ΠΎ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ Π»Π΅Π³ΠΊΠΈΡ
ΠΏΡΠΈ ΠΌΠΎΠ½ΠΎΠ³Π΅Π½Π½ΡΡ
Π³Π΅Π½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΈΠ½Π΄ΡΠΎΠΌΠ°Ρ
. ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ, Π½Π° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΠΊΠΎΡΠΎΡΡΡ
Π±ΡΠ»ΠΈ Π²ΡΠ΄Π΅Π»Π΅Π½Ρ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΊΡΠΈΡΠ΅ΡΠΈΠΈ ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΡ ΡΠ΅ΡΠΏΠΈΡΠ°ΡΠΎΡΠ½ΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΠΏΡΠΈ ΡΠΈΡΠΎΠΊΠΎ ΡΠ°ΡΠΏΡΠΎΡΡΡΠ°Π½Π΅Π½Π½ΡΡ
Π½Π΅Π΄ΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
Π²Π°ΡΠΈΠ°Π½ΡΠ°Ρ
Π½Π°ΡΠ»Π΅Π΄ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΡ ΡΠΎΠ΅Π΄ΠΈΠ½ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΡΠΎΡΡΠΎΡΠ½ΠΈΠ΅ ΠΎΡΠ³Π°Π½ΠΎΠ² Π΄ΡΡ
Π°Π½ΠΈΡ ΠΏΡΠΈ Π΄ΠΈΡΠΏΠ»Π°Π·ΠΈΠΈ ΡΠΎΠ΅Π΄ΠΈΠ½ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ ΠΊΠ°ΠΊ ΠΌΠΎΡΡΠΎΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΠΌΠΈ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡΠΌΠΈ Π΄ΡΡ
Π°ΡΠ΅Π»ΡΠ½ΡΡ
ΠΏΡΡΠ΅ΠΉ ΠΈ Π»Π΅Π³ΠΎΡΠ½ΠΎΠΉ ΠΏΠ°ΡΠ΅Π½Ρ
ΠΈΠΌΡ, ΡΠ°ΠΊ ΠΈ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ΠΌ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
Π²Π½Π΅Π»Π΅Π³ΠΎΡΠ½ΡΡ
ΡΠ°ΠΊΡΠΎΡΠΎΠ². ΠΡΠΌΠ΅ΡΠ΅Π½ΠΎ, ΡΡΠΎ Π±ΠΎΠ»ΡΡΠΈΠ½ΡΡΠ²ΠΎ ΡΠ°Π±ΠΎΡ Π½ΠΎΡΠΈΡ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ ΠΎΠΏΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΠΉ Ρ
Π°ΡΠ°ΠΊΡΠ΅Ρ Π±Π΅Π· ΠΏΠΎΠΏΡΡΠΊΠΈ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΡΡΠ½Π΄Π°ΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
ΠΌΠΎΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈ ΠΏΠ°ΡΠΎΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΡΠ°Π·Π²ΠΈΡΠΈΡ ΡΠΎΠ³ΠΎ ΠΈΠ»ΠΈ ΠΈΠ½ΠΎΠ³ΠΎ Π²ΠΈΠ΄Π° Π±ΡΠΎΠ½Ρ
ΠΎΠ»Π΅Π³ΠΎΡΠ½ΠΎΠΉ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ
Solving the problem of credit defaults in retail sector
The article analyzes dynamics of the volume and annual rate of loan delinquency of the countryβs population for intermediate quarter dates, compares default retail credit portfolios with similar portfolio of organizations, and determines the main reasons for appearance of populationβs debts before banks. It is concluded that it is necessary for banks to focus on development of their own tools and technologies of payment recovery, related to determination of early problematic debt for the purpose of taking preventive measures for preventing the appearance of past-due debts, which is possible under the condition of investing money assets into own analytical and technological tools. An approach to segmentation of debts and factors that could be used as indicators in the process of accompanying and servicing of credits are offered.peer-reviewe
Role of a two-component ResD-ResE system in regulating the expression of guanyl-specific ribonuclease genes in Bacilli
The role of the two-component ResD-ResE signal transduction system in regulating the expression of guanyl-specific ribonuclease genes in bacilli has been studied. Proteins with homologies to the ResD and ResE regulatory proteins of Bacillus subtilis have been found in all sequenced genomes of Bacillus. It has been shown using the B. subtilis strains defective in genes of these proteins that the ResD-ResE signal transduction system positively regulates the expression of ribonuclease genes of B. intermedius, B. pumilus, and B. thuringiensis in cells of B. subtilis. The data obtained in this work speak for the fact that regulatory system similar to the two-component ResD-ResE signal transduction system of B. subtilis also functions in other representatives of the Bacillus genus. Β© 2008 Allerton Press, Inc
- β¦