233 research outputs found
Quantum decoherence and an adiabatic process in macroscopic and mesoscopic systems
Quantum decoherence is of primary importance for relaxation to an equilibrium
distribution and, accordingly, for equilibrium processes. We demonstrate how
coherence breaking implies evolution to a microcanonical distribution
(``microcanonical postulate'') and, on that ground, consider an adiabatic
process, in which there is no thermostat. We stress its difference from a
zero-polytropic process, i.e., a process with zero heat capacity but involving
a thermostat. We find the distribution for the adiabatic process and show that
(i) in the classical limit this distribution is canonical, (ii) for macroscopic
systems, the mean values of energy for adiabatic and zero-polytropic processes
are the same, but its fluctuations are different, and (iii) in general,
adiabatic and zero-polytropic processes are different, which is particularly
essential for mesoscopic systems; for those latter, an adiabatic process is in
general irreversible.Comment: 4 pages, LATEX, Elsevier style espcrc1.sty, to appear in Proceedings
of ISQM-Tokyo '9
Chern-Simons Field Theory and Generalizations of Anyons
It is well known that charges coupled to a pure Chern-Simons gauge field in
(2+1) dimensions undergo an effective change of statistics, i.e., become
anyons. We will consider several generalizations thereof, arising when the
gauge field is more general. The first one is ``multispecies anyons''---charged
particles of several species coupled to one, or possibly several, Chern-Simons
fields. The second one is finite-size anyons, which are charged particles
coupled to a gauge field described by the Chern-Simons term plus some other
term. In fact, rigorously speaking, quasielectrons and quasiholes in the
fractional quantum Hall effect are multispecies finite-size anyons. The third
one is an analog of finite-size anyons which arises in a model with a mixed
Chern-Simons term; notably, this model is P,T-invariant, which opens the way
for practical applications even when there is no parity-breaking magnetic
field.Comment: 6 pages, LATEX. Contributed paper at the International Europhysics
Conference on High Energy Physics HEP-97 (Jerusalem, Israel, 19--26 August
1997
Cosmological Quantum Jump Dynamics I. The Principle of Cosmic Energy Determinacy, Equations of Motion, and Jumps Probabilities
The universe, as a closed system, is for all time in a state with a
determinate value of energy, i.e., in an eigenstate of the Hamiltonian. That is
the principle of cosmic energy determinacy. The Hamiltonian depends on cosmic
time through metric. Therefore there are confluence and branch points of energy
levels. At branch points, quantum jumps must happen to prevent the violation of
energy determinacy. Thus quantum jumps are a reaction against the propensity of
the universe dynamics to that violation. On the basis of this idea, an
internally consistent quantum jump dynamics is developed.Comment: 11 pages, LATEX 2
Notes on Quantum Field Theory in Curved Spacetime: Problems Relating to the Concept of Particles and Hamiltonian Formalism
The aim of these notes is to elucidate some aspects of quantum field theory
in curved spacetime, especially those relating to the notion of particles. A
selection of issues relevant to wave-particle duality is given. The case of a
generic curved spacetime is outlined. A Hamiltonian formulation of quantum
field theory in curved spacetime is elaborated for a preferred reference frame
with a separated space metric (a static spacetime and a reductive synchronous
reference frame). Applications: (1) Black hole. (2) The universe; the
cosmological redshift is obtained in the context of quantum field theory.Comment: 27 pages, LaTeX 2e. Substantially extended, sections on applications
to black hole and universe adde
Pulsating Massive Star: Phase Transitions in Superdense Matter
In the case of the energy-momentum tensor related to "ordinary" matter
(perfect fluid representing spin 1/2 and 1 fields), the equations of general
relativity result in cosmological and gravitational collapse singularities--due
to the fulfilment of both the strong and weak energy conditions. According to
great unified theories, in superdense matter (both hot and cold), phase
transitions take place, symmetry between the strong and electroweak
interactions is restored/broken, and a scalar field is created/annihilated. In
the scalar field regime, the strong energy condition is broken, but the weak
one holds. However, the continuity condition for the pressure on the surface of
a contracting star results in the occurrence of a compensating pseudomatter
field, for which both energy conditions are broken. On this basis, for a
massive star predisposed to a gravitational collapse, a pulsation dynamics with
no singularity is constructed.Comment: 15 pages, LaTeX 2
General Relativity and Quantum Jumps: The Existence of Nondiffeomorphic Solutions to the Cauchy Problem in Nonempty Spacetime and Quantum Jumps as a Provider of a Canonical Spacetime Structure
It is shown that in spite of a generally accepted concept, there exist
nondiffeomorphic solutions to the Cauchy problem in nonempty spacetime, which
implies the necessity for canonical complementary conditions. It is nonlocal
quantum jumps that provide a canonical global structure of spacetime manifold
and, by the same token, the canonical complementary conditions.Comment: 13 pages, LATEX 2
Comment on ``Additional analytically exact solutions for three-anyons'' and ``Fermion Ground State of Three Particles in a Harmonic Potential Well and Its Anyon Interpolation''
The claim put forward in [hep-th/9512051, hep-th/9612244] that the energies
of the ``missing'' states of three anyons in a harmonic potential depend
linearly on the statistics parameter, is incorrect because the wave functions
proposed do not satisfy the anyonic interchange conditions.Comment: 2 pages, LATEX 2.0
Quantum Fields in Curved Spacetime: Quantum-Gravitational Nonlocality and Conservation of Particle Numbers
We argue that the conventional quantum field theory in curved spacetime has a
grave drawback: The canonical commutation relations for quantum fields and
conjugate momenta do not hold. Thus the conventional theory should be denounced
and the related results revised. A Hamiltonian version of the canonical
formalism for a free scalar quantum field is advanced, and the fundamentals of
an appropriate theory are constructed. The principal characteristic feature of
the theory is quantum-gravitational nonlocality: The Schroedinger field
operator at time t depends on the metric at t in the whole 3-space.
Applications to cosmology and black holes are given, the results being in
complete agreement with those of general relativity for particles in curved
spacetime. A model of the universe is advanced, which is an extension of the
Friedmann universe; it lifts the problem of missing dark matter. A fundamental
and shocking result is the following: There is no particle creation in the case
of a free quantum field in curved spacetime; in particular, neither the
expanding universe nor black holes create particles.Comment: 17 pages, no figures, LATEX 2.0
On Cosmological Spacetime Structure and Symmetry: Manifold as a Lie Group, Spinor Structure and Symmetry Group, Minkowski Metric, and Unnecessariness of Double-Valued Representations
It is shown that cosmological spacetime manifold has the structure of a Lie
group and a spinor space. This leads naturally to the Minkowski metric on
tangent spaces and the Lorentzian metric on the manifold and makes it possible
to dispense with double-valued representations.Comment: 12 pages, LaTeX 2
Indeterministic Quantum Gravity and Cosmology IX. Nonreality of Many-Place Gravitational Autolocalization: Why a Ball Is Not Located in Different Places at Once
This paper is a sequel to the series of papers [gr-qc/9409010, gr-qc/9505034,
gr-qc/9603022, gr-qc/9609035, gr-qc/9609046, gr-qc/9704033, gr-qc/9704038,
gr-qc/9708014], being an immediate continuation and supplement to the last of
them, where gravitational autolocalization of a body has been considered. A
resulting solution, which describes a one-place location, has been called
gravilon. Here it is shown that a gravilon is the only solution, i.e., that
many-place gravitational autolocalization is unreal. This is closely related to
nonreality of tunneling in the conditions under consideration.Comment: 5 pages, LATEX 2.0
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