1,109 research outputs found
New series of 3D lattice integrable models
In this paper we present a new series of 3-dimensional integrable lattice
models with colors. The case generalizes the elliptic model of our
previous paper. The weight functions of the models satisfy modified tetrahedron
equations with states and give a commuting family of two-layer
transfer-matrices. The dependence on the spectral parameters corresponds to the
static limit of the modified tetrahedron equations and weights are
parameterized in terms of elliptic functions. The models contain two free
parameters: elliptic modulus and additional parameter . Also we briefly
discuss symmetry properties of weight functions of the models.Comment: 17 pages, IHEP-93-126, Late
New solution of vertex type tetrahedron equations
In this paper we formulate a new N-state spin integrable model on a
three-dimensional lattice with spins interacting round each elementary cube of
the lattice. This model can be also reformulated as a vertex type model. Weight
functions of the model satisfy tetrahedron equations.Comment: 12 pages, LaTeX, IHEP-94-10
- Vectors for Three Dimensional Models
In this paper we apply the method of psi-vectors to three dimensional
statistical models. This method gives the correspondence between the Bazhanov
-- Baxter model and its vertex formulation. Considering psi-vectors for the
Planar model, we obtain its self-duality.Comment: 11 pages, LaTeX, no figure
BLR kinematics and Black Hole Mass in Markarian 6
We present results of the optical spectral and photometric observations of
the nucleus of Markarian 6 made with the 2.6-m Shajn telescope at the Crimean
Astrophysical Observatory. The continuum and emission Balmer line intensities
varied more than by a factor of two during 1992-2008. The lag between the
continuum and Hbeta emission line flux variations is 21.1+-1.9 days. For the
Halpha line the lag is about 27 days but its uncertainty is much larger. We use
Monte-Carlo simulation of the random time series to check the effect of our
data sampling on the lag uncertainties and we compare our simulation results
with those obtained by random subset selection (RSS) method of Peterson et al.
(1998). The lag in the high-velocity wings are shorter than in the line core in
accordance with the virial motions. However, the lag is slightly larger in the
blue wing than in the red wing. This is a signature of the infall gas motion.
Probably the BLR kinematic in the Mrk 6 nucleus is a combination of the
Keplerian and infall motions. The velocity-delay dependence is similar for
individual observational seasons. The measurements of the Hbeta line width in
combination with the reverberation lag permits us to determine the black hole
mass, M_BH=(1.8+-0.2)x10^8 M_sun. This result is consistent with the AGN
scaling relationships between the BLR radius and the optical continuum
luminosity (R_BLR is proportional to L^0.5) as well as with the black-hole
mass-luminosity relationship (M_BH-L) under the Eddington luminosity ratio for
Mrk 6 to be L_bol/L_Edd ~ 0.01.Comment: 17 pages, 10 figures, accepted for publication in MNRA
Phase transition at exceptional point in Hermitian systems
Exceptional point (EP) is a spectral singularity in non-Hermitian systems.
The passing over the EP leads to a phase transition which endows the system
with unconventional features that find a wide range of applications. However,
the need of using the dissipation and amplification limits the possible
applications of systems with the EP. In this work, the concept of phase
transitions at the EP is expanded to Hermitian systems which are free from
dissipation and amplification. It is considered a composite Hermitian system
including both two coupled subsystems and their environment consisting only of
several tens degrees of freedom such that the energy can return from the
environment to the subsystems. It is shown that the dynamics of such a
Hermitian system demonstrates a clear phase transition. It occurs at the
critical coupling strength between subsystems corresponding to the EP in the
non-Hermitian system. This phase transition manifests itself even in the
non-Markovian regime of the system dynamics in which collapses and revivals of
the energy occur. A photonic circuit is proposed for observing the EP phase
transition in systems free from dissipation and amplification. The obtained
results extend the range of practical applications of the EP phenomena to
Hermitian systems.Comment: 16 pages, 8 figure
Self-consistent description of relaxation processes in systems with ultra- and deep-strong coupling
An ultra-strong coupling regime takes place in a compound system when a
coupling strength between the subsystems exceeds one tenth of the system
eigenfrequency. It transforms into a deep-strong coupling regime when the
coupling strength exceeds the system eigenfrequency. In these regimes, there
are difficulties with description of relaxation processes without explicit
considering of environment degrees of freedom. To correctly evaluate the
relaxation rates, it is necessary to consider the interaction of the system
with its environment taking into account the counter-rotating wave and
diamagnetic terms. We develop a self-consistent theory for calculation of the
relaxation rates in the systems, in which the coupling strength is of the order
of the system eigenfrequency. We demonstrate that the increase in the coupling
strength can lead to a significant decrease in the relaxation rates. In
particular, we show that for frequency-independent density of states of the
environment, the relaxation rates decrease exponentially with the increase in
the coupling strength. This fact can be used to suppress losses by tuning the
strength coupling and the environment states
Effects of Electron-Electron and Electron-Phonon Interactions in Weakly Disordered Conductors and Heterostuctures
We investigate quantum corrections to the conductivity due to the
interference of electron-electron (electron-phonon) scattering and elastic
electron scattering in weakly disordered conductors. The electron-electron
interaction results in a negative -correction in a 3D conductor. In
a quasi-two-dimensional conductor, ( is the thickness, is
the Fermi velocity), with 3D electron spectrum this correction is linear in
temperature and differs from that for 2D electrons (G. Zala et. al., Phys.
Rev.B {\bf 64}, 214204 (2001)) by a numerical factor. In a
quasi-one-dimensional conductor, temperature-dependent correction is
proportional to . The electron interaction via exchange of virtual phonons
also gives -correction. The contribution of thermal phonons interacting
with electrons via the screened deformation potential results in -term and
via unscreened deformation potential results in -term. The interference
contributions dominate over pure electron-phonon scattering in a wide
temperature range, which extends with increasing disorder.Comment: 6 pages, 2figure
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