89 research outputs found
Binary N-Step Markov Chain as an Exactly Solvable Model of Long-Range Correlated Systems
A theory of systems with long-range correlations based on the consideration
of binary N-step Markov chains is developed. In our model, the conditional
probability that the i-th symbol in the chain equals zero (or unity) is a
linear function of the number of unities among the preceding N symbols. The
model allows exact analytical treatment. The correlation and distribution
functions as well as the variance of number of symbols in the words of
arbitrary length L are obtained analytically and numerically. A self-similarity
of the studied stochastic process is revealed and the similarity transformation
of the chain parameters is presented. The diffusion equation governing the
distribution function of the L-words is explored. If the persistent
correlations are not extremely strong, the distribution function is shown to be
the Gaussian with the variance being nonlinearly dependent on L. The
applicability of the developed theory to the coarse-grained written and DNA
texts is discussed.Comment: LaTeX2e, 16 pages, 9 figure
Comment on cond-mat/0107336 ``Critical State Theory for Nonparallel Flux Line Lattices in Type-II Superconductors''
Comment on the paper "Critical State Theory for Nonparallel Flux Line
Lattices in Type-II Superconductors" by A. Badia and C. Lopez is presented
here.Comment: 1 pag
Memory Functions of the Additive Markov chains: Applications to Complex Dynamic Systems
A new approach to describing correlation properties of complex dynamic
systems with long-range memory based on a concept of additive Markov chains
(Phys. Rev. E 68, 061107 (2003)) is developed. An equation connecting a memory
function of the chain and its correlation function is presented. This equation
allows reconstructing the memory function using the correlation function of the
system. Thus, we have elaborated a novel method to generate a sequence with
prescribed correlation function. Effectiveness and robustness of the proposed
method is demonstrated by simple model examples. Memory functions of concrete
coarse-grained literary texts are found and their universal power-law behavior
at long distances is revealed.Comment: 5 pages, 5 figures, changes of minor nature, 1 figure adde
Continuous stochastic processes with non-local memory
We study the non-Markovian random continuous processes described by the
Mori-Zwanzig equation. As a starting point, we use the Markovian Gaussian
Ornstein-Uhlenbeck process and introduce an integral memory term depending on
the past of the process into expression for the higher-order transition
probability function and stochastic differential equation. We show that the
proposed processes can be considered as continuous-time interpolations of
discrete-time higher-order autoregressive sequences. An equation connecting the
memory function (the kernel of integral term) and the two-point correlation
function is obtained. A condition for stationarity of the process is
established. We suggest a method to generate stationary continuous stochastic
processes with prescribed pair correlation function. As illustration, some
examples of numerical simulation of the processes with non-local memory are
presented.Comment: 7 pages, 2 figure
Rank distributions of words in additive many-step Markov chains and the Zipf law
The binary many-step Markov chain with the step-like memory function is
considered as a model for the analysis of rank distributions of words in
stochastic symbolic dynamical systems. We prove that the envelope curve for
this distribution obeys the power law with the exponent of the order of unity
in the case of rather strong persistent correlations. The Zipf law is shown to
be valid for the rank distribution of words with lengths about and shorter than
the correlation length in the Markov sequence. A self-similarity in the rank
distribution with respect to the decimation procedure is observed.Comment: 4pages, 3 figure
Terahertz Transverse-Electric- and Transverse-Magnetic-polarized waves localized on graphene in photonic crystals
We predict the coexistence of both TE- and TM-polarized localized
electromagnetic waves that can propagate \emph{in the same frequency range}
along a graphene layer inserted in a photonic crystal. In addition, we studied
the excitation of these modes by an external wave and have shown that the
resonance peaks of the sample transmissivity should be observed due to the
excitation of the localized waves, independently of the polarization of the
exciting wave. The simplicity of the derived dispersion relations for the
localized modes and the possibility to excite waves of both polarizations
provide a method for measuring graphene conductivity.Comment: This manuscript was extended to 7 pages and 8 figures and published
in PR
Nonlinear Effect of Transport Current on Response of Metals to Electromagnetic Radiation
The nonlinear interaction of DC current flowing in a thin metal film with an
external low-frequency AC electromagnetic field is studied theoretically. The
nonlinearity is related to the influence of the magnetic field of the DC
current and the magnetic field of the wave on the form of electron
trajectories. This magnetodynamic mechanism of nonlinearity is the most typical
for pure metals at low temperatures. We find that such interaction causes sharp
kinks in the temporal dependence of the AC electric field of the wave on
surface of the sample. The phenomenon of amplification of the electromagnetic
signal on the metal surface is predicted. We also calculate the nonlinear
surface impedance and show that it turns out to be imaginary-valued and its
modulus decreases drastically with the increase of the wave amplitude.Comment: RevTex, 13 pages, 5 figure
Equivalence of Markov's Symbolic Sequences to Two-Sided Chains
A new object of the probability theory, two-sided chain of events (symbols),
is introduced. A theory of multi-steps Markov chains with long-range memory,
proposed earlier in Phys. Rev. E 68, 06117 (2003), is developed and used to
establish the correspondence between these chains and two-sided ones. The
Markov chain is proved to be statistically equivalent to the definite two-sided
one and vice versa. The results obtained for the binary chains are generalized
to the chains taking on the arbitrary number of states.Comment: 5 page
High-Order Correlation Functions of Binary Multi-Step Markov Chains
Two approaches to studying the correlation functions of the binary Markov
sequences are considered. The first of them is based on the study of
probability of occurring different ''words'' in the sequence. The other one
uses recurrence relations for correlation functions. These methods are applied
for two important particular classes of the Markov chains. These classes
include the Markov chains with permutative conditional probability functions
and the additive Markov chains with the small memory functions. The exciting
property of the self-similarity (discovered in Phys. Rev. Lett. 90, 110601
(2003) for the additive Markov chain with the step-wise memory function) is
proved to be the intrinsic property of any permutative Markov chain.
Applicability of the correlation functions of the additive Markov chains with
the small memory functions to calculating the thermodynamic characteristics of
the classical Ising spin chain with long-range interaction is discussed.Comment: 9 page
Non-extensive thermodynamics of 1D systems with long-range interaction
A new approach to non-extensive thermodynamical systems with non-additive
energy and entropy is proposed. The main idea of the paper is based on the
statistical matching of the thermodynamical systems with the additive
multi-step Markov chains. This general approach is applied to the Ising spin
chain with long-range interaction between its elements. The asymptotical
expressions for the energy and entropy of the system are derived for the
limiting case of weak interaction. These thermodynamical quantities are found
to be non-proportional to the length of the system (number of its particle).Comment: 5 pages, 2 figure
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