3,446 research outputs found
The 1/N-expansion, quantum-classical correspondence and nonclassical states generation in dissipative higher-order anharmonic oscillators
We develop a method for the determination of thecdynamics of dissipative
quantum systems in the limit of large number of quanta N, based on the
1/N-expansion of Heidmann et al. [ Opt. Commun. 54, 189 (1985) ] and the
quantum-classical correspondence. Using this method, we find analytically the
dynamics of nonclassical states generation in the higher-order anharmonic
dissipative oscillators for an arbitrary temperature of a reservoir. We show
that the quantum correction to the classical motion increases with time
quadratically up to some maximal value, which is dependent on the degree of
nonlinearity and a damping constant, and then it decreases. Similarities and
differences with the corresponding behavior of the quantum corrections to the
classical motion in the Hamiltonian chaotic systems are discussed. We also
compare our results obtained for some limiting cases with the results obtained
by using other semiclassical tools and discuss the conditions for validity of
our approach.Comment: 15 pages, RevTEX (EPSF-style), 3 figs. Replaced with final version
(stylistic corrections
Decomposable representations and Lagrangian submanifolds of moduli spaces associated to surface groups
In this paper, we construct a Lagrangian submanifold of the moduli space
associated to the fundamental group of a punctured Riemann surface (the space
of representations of this fundamental group into a compact connected Lie
group). This Lagrangian submanifold is obtained as the fixed-point set of an
anti-symplectic involution defined on the moduli space. The notion of
decomposable representation provides a geometric interpretation of this
Lagrangian submanifold
Hamiltonian Quantization of Chern-Simons theory with SL(2,C) Group
We analyze the hamiltonian quantization of Chern-Simons theory associated to
the universal covering of the Lorentz group SO(3,1). The algebra of observables
is generated by finite dimensional spin networks drawn on a punctured
topological surface. Our main result is a construction of a unitary
representation of this algebra. For this purpose, we use the formalism of
combinatorial quantization of Chern-Simons theory, i.e we quantize the algebra
of polynomial functions on the space of flat SL(2,C)-connections on a
topological surface with punctures. This algebra admits a unitary
representation acting on an Hilbert space which consists in wave packets of
spin-networks associated to principal unitary representations of the quantum
Lorentz group. This representation is constructed using only Clebsch-Gordan
decomposition of a tensor product of a finite dimensional representation with a
principal unitary representation. The proof of unitarity of this representation
is non trivial and is a consequence of properties of intertwiners which are
studied in depth. We analyze the relationship between the insertion of a
puncture colored with a principal representation and the presence of a
world-line of a massive spinning particle in de Sitter space.Comment: 78 pages. Packages include
On dynamical adjoint functor
We give an explicit formula relating the dynamical adjoint functor and
dynamical twist over nonalbelian base to the invariant pairing on parabolic
Verma modules. As an illustration, we give explicit - and
-invariant star product on projective spaces
Probes of Lorentz Violation in Neutrino Propagation
It has been suggested that the interactions of energetic particles with the
foamy structure of space-time thought to be generated by quantum-gravitational
(QG) effects might violate Lorentz invariance, so that they do not propagate at
a universal speed of light. We consider the limits that may be set on a linear
or quadratic violation of Lorentz invariance in the propagation of energetic
neutrinos, v/c=[1 +- (E/M_\nuQG1)] or [1 +- (E/M_\nu QG2}^2], using data from
supernova explosions and the OPERA long-baseline neutrino experiment. Using the
SN1987a neutrino data from the Kamioka II, IMB and Baksan experiments, we set
the limits M_\nuQG1 > 2.7(2.5)x10^10 GeV for subluminal (superluminal)
propagation, respectively, and M_\nuQG2 >4.6(4.1)x10^4 GeV at the 95%
confidence level. A future galactic supernova at a distance of 10 kpc would
have sensitivity to M_\nuQG1 > 2(4)x10^11 GeV for subluminal (superluminal)
propagation, respectively, and M_\nuQG2 > 2(4)x10^5 GeV. With the current CNGS
extraction spill length of 10.5 micro seconds and with standard clock
synchronization techniques, the sensitivity of the OPERA experiment would reach
M_\nuQG1 ~ 7x10^5 GeV (M_\nuQG2 ~ 8x10^3 GeV) after 5 years of nominal running.
If the time structure of the SPS RF bunches within the extracted CNGS spills
could be exploited, these figures would be significantly improved to M_\nuQG1 ~
5x10^7 GeV (M_\nuQG2 ~ 4x10^4 GeV). These results can be improved further if
similar time resolution can be achieved with neutrino events occurring in the
rock upstream of the OPERA detector: we find potential sensitivities to
M_\nuQG1 ~ 4x10^8 GeV and M_\nuQG2 ~ 7x10^5 GeV.Comment: 33 pages, 22 figures, version accepted for publication in Physical
Review
Nonperturbative Contributions in an Analytic Running Coupling of QCD
In the framework of analytic approach to QCD the nonperturbative
contributions in running coupling of strong interaction up to 4-loop order are
obtained in an explicit form. For all they are shown to be
represented in the form of an expansion in inverse powers of Euclidean momentum
squared. The expansion coefficients are calculated for different numbers of
active quark flavors and for different number of loops taken into
account. On basis of the stated expansion the effective method for precise
calculation of the analytic running coupling can be developed.Comment: 9 pages, LaTeX, 1 table, 1 eps figur
The scenario approach to the development of regional waste management systems (Implementation experience in the regions of Russia)
The article illustrates a theoretical approach to scenario modeling of economic indicators of regional waste management system. The method includes a three-iterative algorithm that allows the executive authorities and investors to take a decision on logistics, bulk, technological and economic parameters of the formation of the regional long-term (10-25 years) waste management program. © 2016 Fomin et al
Resummations in the Bloch-Nordsieck model
We studied different levels of resummations of the exactly solvable
Bloch-Nordsieck model in order to be able to compare the approximations with an
exact result. We studied one-loop perturbation theory, 2PI resummation and
Schwinger-Dyson equations truncated in a way to maintain Ward-identities. At
all levels we carefully performed renormalization. We found that although the
2PI resummation does not exhibit infrared sensitivity at the mass shell (the
one-loop perturbation theory does), but it is still far from the exact
solution. The method of truncated Schwinger-Dyson equations, however, is exact
in this model, so it provides a new way of solving the Bloch-Nordsieck model.
This method can also be generalized to other, more complicated theories.Comment: 12 pages, 3 figures, revtex
Fractional and unquantized dc voltage generation in THz-driven semiconductor superlattices
We consider the spontaneous creation of a dc voltage across a strongly
coupled semiconductor superlattice subjected to THz radiation. We show that the
dc voltage may be approximately proportional either to an integer or to a half-
integer multiple of the frequency of the applied ac field, depending on the
ratio of the characteristic scattering rates of conducting electrons. For the
case of an ac field frequency less than the characteristic scattering rates, we
demonstrate the generation of an unquantized dc voltage.Comment: 6 pages, 3 figures, RevTEX, EPSF. Revised version v3: corrected typo
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