129 research outputs found
One particular approach to the non-equilibrium quantum dynamics
We present a particular approach to the non-equilibrium dynamics of quantum
field theory. This approach is based on the Jaynes-Gibbs principle of the
maximal entropy and its implementation, throghout the initial value data, into
the dynamical equations for Green's functions.Comment: 5 pages, 2 figures. Published in the Proceedings of the 8th Mexican
School of Particles and Fields (VIII-EMPC), Oaxaca de Juarez, Mexico, 20-28
Nov 199
Dissipation and quantization for composite systems
In the framework of 't Hooft's quantization proposal, we show how to obtain
from the composite system of two classical Bateman's oscillators a quantum
isotonic oscillator. In a specific range of parameters, such a system can be
interpreted as a particle in an effective magnetic field, interacting through a
spin-orbit interaction term. In the limit of a large separation from the
interaction region one can describe the system in terms of two irreducible
elementary subsystems which correspond to two independent quantum harmonic
oscillators.Comment: 9 page
A framework for dynamical generation of flavor mixing
We present a dynamical mechanism \`a la Nambu--Jona-Lasinio for the
generation of masses and mixing for two interacting fermion fields. The
analysis is carried out in the framework introduced long ago by Umezawa et al.,
in which mass generation is achieved via inequivalent representations, and that
we generalize to the case of two generations. The method allows a clear
identification of the vacuum structure for each physical phase, confirming
previous results about the distinct physical nature of the vacuum for fields
with definite mass and fields with definite flavor. Implications for the
leptonic sector of the Standard Model are briefly discussed.Comment: 13 pages. Presented at "Symmetries in Science XVI, Bregenz 2013
Dirac lattice
We study the emergence of Dirac fermionic field in the low energy description
of non-relativistic dynamical models on graphs admitting continuum limit. The
Dirac fermionic field appears as the effective field describing the excitations
above point-like Fermi surface. Together with the Dirac fermionic field an
effective space-time metric is also emerging. We analyze the conditions for
such Fermi points to appear in general, paying special attention to the cases
of two and three spacial dimensions.Comment: 26 pages, 4 figures; typo and grammatical corrections, new
reference(s) added, version accepted for publicatio
Information scan of quantum states based on entropy-power uncertainty relations
We use Renyi-entropy-power-based uncertainty relations to show how the information probability distribution associated with a quantum state can be reconstructed in a process that is analogous to quantum-state tomography. We illustrate our point with the so-called "cat states", which are of both fundamental interest and practical use in schemes such as quantum metrology, but are not well described by standard variance-based approaches
Quantization, group contraction and zero point energy
We study algebraic structures underlying 't Hooft's construction relating
classical systems with the quantum harmonic oscillator. The role of group
contraction is discussed. We propose the use of SU(1,1) for two reasons:
because of the isomorphism between its representation Hilbert space and that of
the harmonic oscillator and because zero point energy is implied by the
representation structure. Finally, we also comment on the relation between
dissipation and quantization.Comment: 6 pages, 3 figure
Heat Bath Particle Number Spectrum
We calculate the number spectrum of particles radiated during a scattering
into a heat bath using the thermal largest-time equation and the
Dyson-Schwinger equation. We show how one can systematically calculate
{d}/{d\omega} to any order using modified real time
finite-temperature diagrams. Our approach is demonstrated on a simple model
where two scalar particles scatter, within a photon-electron heat bath, into a
pair of charged particles and it is shown how to calculate the resulting
changes in the number spectra of the photons and electrons.Comment: 29 pages, LaTeX; 14 figure
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