63 research outputs found
Voting and Catalytic Processes with Inhomogeneities
We consider the dynamics of the voter model and of the monomer-monomer
catalytic process in the presence of many ``competing'' inhomogeneities and
show, through exact calculations and numerical simulations, that their presence
results in a nontrivial fluctuating steady state whose properties are studied
and turn out to specifically depend on the dimensionality of the system, the
strength of the inhomogeneities and their separating distances. In fact, in
arbitrary dimensions, we obtain an exact (yet formal) expression of the order
parameters (magnetization and concentration of adsorbed particles) in the
presence of an arbitrary number of inhomogeneities (``zealots'' in the
voter language) and formal similarities with {\it suitable electrostatic
systems} are pointed out. In the nontrivial cases , we explicitly
compute the static and long-time properties of the order parameters and
therefore capture the generic features of the systems. When , the problems
are studied through numerical simulations. In one spatial dimension, we also
compute the expressions of the stationary order parameters in the completely
disordered case, where is arbitrary large. Particular attention is paid to
the spatial dependence of the stationary order parameters and formal
connections with electrostatics.Comment: 17 pages, 6 figures, revtex4 2-column format. Original title ("Are
Voting and Catalytic Processes Electrostatic Problems ?") changed upon
editorial request. Minor typos corrected. Published in Physical Review
Bi-defects of Nematic Surfactant Bilayers
We consider the effects of the coupling between the orientational order of
the two monolayers in flat nematic bilayers. We show that the presence of a
topological defect on one bilayer generates a nontrivial orientational texture
on both monolayers. Therefore, one cannot consider isolated defects on one
monolayer, but rather associated pairs of defects on either monolayer, which we
call bi-defects. Bi-defects generally produce walls, such that the textures of
the two monolayers are identical outside the walls, and different in their
interior. We suggest some experimental conditions in which these structures
could be observed.Comment: RevTeX, 4 pages, 3 figure
Quantum Computer with Mixed States and Four-Valued Logic
In this paper we discuss a model of quantum computer in which a state is an
operator of density matrix and gates are general quantum operations, not
necessarily unitary. A mixed state (operator of density matrix) of n two-level
quantum systems is considered as an element of 4^n-dimensional operator Hilbert
space (Liouville space). It allows to use a quantum computer model with
four-valued logic. The gates of this model are general superoperators which act
on n-ququat state. Ququat is a quantum state in a four-dimensional (operator)
Hilbert space. Unitary two-valued logic gates and quantum operations for an
n-qubit open system are considered as four-valued logic gates acting on
n-ququat. We discuss properties of quantum four-valued logic gates. In the
paper we study universality for quantum four-valued logic gates.Comment: 17 page
Экспериментальное исследование процессов столкновения капель распыленной воды в потоке высокотемпературных газов
The Hamiltonian Structure of the Second Painleve Hierarchy
In this paper we study the Hamiltonian structure of the second Painleve
hierarchy, an infinite sequence of nonlinear ordinary differential equations
containing PII as its simplest equation. The n-th element of the hierarchy is a
non linear ODE of order 2n in the independent variable depending on n
parameters denoted by and . We introduce new
canonical coordinates and obtain Hamiltonians for the and
evolutions. We give explicit formulae for these Hamiltonians showing that they
are polynomials in our canonical coordinates
Анализ эффективности использования попутного нефтяного газа для выработки электроэнергии на линейном нефтяном месторождении
Rational solutions of the discrete time Toda lattice and the alternate discrete Painleve II equation
The Yablonskii-Vorob'ev polynomials , which are defined by a second
order bilinear differential-difference equation, provide rational solutions of
the Toda lattice. They are also polynomial tau-functions for the rational
solutions of the second Painlev\'{e} equation (). Here we define
two-variable polynomials on a lattice with spacing , by
considering rational solutions of the discrete time Toda lattice as introduced
by Suris. These polynomials are shown to have many properties that are
analogous to those of the Yablonskii-Vorob'ev polynomials, to which they reduce
when . They also provide rational solutions for a particular
discretisation of , namely the so called {\it alternate discrete}
, and this connection leads to an expression in terms of the Umemura
polynomials for the third Painlev\'{e} equation (). It is shown that
B\"{a}cklund transformation for the alternate discrete Painlev\'{e} equation is
a symplectic map, and the shift in time is also symplectic. Finally we present
a Lax pair for the alternate discrete , which recovers Jimbo and Miwa's
Lax pair for in the continuum limit .Comment: 23 pages, IOP style. Title changed, and connection with Umemura
polynomials adde
Comment on "Periodic Phase Synchronization in Coupled Chaotic Oscillators"
2 pages.-- PACS numbers: 05.45.Xt, 05.45.Pq.-- Final full-text version of the paper available at: http://dx.doi.org/10.1103/PhysRevE.73.038201.Kye et al. [Phys. Rev. E 68, 025201(R) (2003)] have recently claimed that, before the onset of Chaotic Phase Synchronization in coupled phase coherent oscillators, there exists a temporally coherent state called Periodic Phase Synchronization (PPS). Here we give evidence that some of their numerical calculations are flawed, while we provide theoretical arguments that indicate that PPS is not to be expected generically in this type of systems.This work was supported by MEC (Spain) and FEDER
under Grant Nos. BFM2001-0341-C02-02, FIS2004-00953 (CONOCE2), and FIS2004-05073-C04-03.http://dx.doi.org/10.1103/PhysRevE.73.03820
Dehydration of emulsified lubricating oil by three fields: swirl centrifugal field, pulse electric field and vacuum temperature field
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