2,271 research outputs found
Child universes UV regularization?
It is argued that high energy density excitations, responsible for UV
divergences in quantum field theories, including quantum gravity, are likely to
be the source of child universes which carry them out of the original space
time. This decoupling prevents these high UV excitations from having any
influence on physical amplitudes. Child universe production could therefore be
responsible for UV regularization in quantum field theories which takes into
account gravitational effects. Also child universe production in the last
stages of black hole evaporation, the prediction of absence of tranplanckian
primordial perturbations, connection to the minimum length hypothesis and in
particular connection to the maximal curvature hypothesis are discussed.Comment: 6 pages, RevTex, discussion to the maximum curvature hypothesis adde
Wormholes and Child Universes
Evidence to the case that classical gravitation provides the clue to make
sense out of quantum gravity is presented. The key observation is the existence
in classical gravitation of child universe solutions or "almost" solutions,
"almost" because of some singularity problems. The difficulties of these child
universe solutions due to their generic singularity problems will be very
likely be cured by quantum effects, just like for example "almost" instanton
solutions are made relevant in gauge theories with breaking of conformal
invariance. Some well motivated modifcations of General Relativity where these
singularity problems are absent even at the classical level are discussed. High
energy density excitations, responsible for UV divergences in quantum field
theories, including quantum gravity, are likely to be the source of child
universes which carry them out of the original space time. This decoupling
could prevent these high UV excitations from having any influence on physical
amplitudes. Child universe production could therefore be responsible for UV
regularization in quantum field theories which take into account
semiclassically gravitational effects. Child universe production in the last
stages of black hole evaporation, the prediction of absence of tranplanckian
primordial perturbations, connection to the minimum length hypothesis and in
particular the connection to the maximal curvature hypothesis are discussed.
Some discussion of superexcited states in the case these states are Kaluza
Klein excitations is carried out. Finally, the posibility of obtaining "string
like" effects from the wormholes associated with the child universes is
discussed.Comment: Talk presented at the IWARA 2009 Conference, Maresias, Brazil,
October 2009, accepted for publication in the proceedings, World Scientific
format, 8 page
Unitary quantization and para-Fermi statistics of order two
A connection between a unitary quantization scheme and para-Fermi statistics
of order 2 is considered. An appropriate extension of Green's ansatz is
suggested. This extension allows one to transform bilinear and trilinear
commutation relations for the annihilation and creation operators of two
different para-Fermi fields and into identity. The way of
incorporating para-Grassmann numbers into a general scheme of
uniquantization is also offered. For parastatistics of order 2 a new fact is
revealed, namely, the trilinear relations containing both the para-Grassmann
variables and the field operators , under a certain
invertible mapping go over into the unitary equivalent relations, where
commutators are replaced by anticommutators and vice versa. It is shown that
the consequence of this circumstance is the existence of two alternative
definitions of the coherent state for para-Fermi oscillators. The Klein
transformation for Green's components of the operators , is
constructed in an explicit form that enables us to reduce the initial
commutation rules for the components to the normal commutation relations of
ordinary Fermi fields. A nontrivial connection between trilinear commutation
relations of the unitary quantization scheme and so-called Lie-supertriple
system is analysed. A brief discussion of the possibility of embedding the
Duffin-Kemmer-Petiau theory into the unitary quantization scheme is provided.Comment: 44 pages, the version published in J. Exp. Theor. Phy
Second-layer nucleation in coherent Stranski-Krastanov growth of quantum dots
We have studied the monolayer-bilayer transformation in the case of the
coherent Stranski-Krastanov growth. We have found that the energy of formation
of a second layer nucleus is largest at the center of the first-layer island
and smallest on its corners. Thus nucleation is expected to take place at the
corners (or the edges) rather than at the center of the islands as in the case
of homoepitaxy. The critical nuclei have one atom in addition to a compact
shape, which is either a square of i*i or a rectangle of i*(i-1) atoms, with
i>1 an integer. When the edge of the initial monolayer island is much larger
than the critical nucleus size, the latter is always a rectangle plus an
additional atom, adsorbed at the longer edge, which gives rise to a new atomic
row in order to transform the rectangle into the equilibrium square shape.Comment: 6 pages, 4 figures. Accepted version, minor change
Influence of Intra-cell Traffic on the Output Power of Base Station in GSM
In this paper we analyze the influence of intracell traffic in a GSM cell on the base station output power. It is proved that intracell traffic increases this power. If offered traffic is small, the increase of output power is equal to the part of intracell traffic. When the offered traffic and, as the result, call loss increase, the increase of output power becomes less. The results of calculation are verified by the computer simulation of traffic process in the GSM cell. The calculation and the simulation consider the uniform distribution of mobile users in the cell, but the conclusions are of a general nature
THE DEVICE OF THE ELECTRO-JIGSAW. EXPERIMENTAL STUDY OF THE CHARACTERISTICS OF THE ELECTRO-JIGSAW.
Lobzik (from German Laubsäge) is a tool for curvilinear sawing of materials. Manual mechanical Jigsaw includes an arched frame with a handle and clamps for mounting the saw blade. The saw blade is thin and narrow, thanks to which it is possible to change the direction of sawing. The frame has a large clearance between the canvas and its top, so it can bypass the edges of the workpiece. Manual jigsaw is usually used for processing of wood and its derivatives (in particular, plywood), and also in jeweller practice for processing nonferrous metals. Electric Jigsaw is a hand-held power tool for sawing of various materials with reciprocating movement of saw blade (Fig. 1). The manual electric Jigsaw includes a hull with a flat platform at the bottom and a handle at the top. Inside is an electric motor and a mechanism that transforms the rotational motion of the engine shaft into the reciprocating movement of the guide. For fastening of cloths the shank with a clamping screw or a spring clamp is used
Hamiltonian formalism for Bose excitations in a plasma with a non-Abelian interaction
We have developed the Hamiltonian theory for collective longitudinally
polarized colorless excitations (plasmons) in a high-temperature gluon plasma
using the general formalism for constructing the wave theory in nonlinear media
with dispersion, which was developed by V.E. Zakharov. In this approach, we
have explicitly obtained a special canonical transformation that makes it
possible to simplify the Hamiltonian of interaction of soft gluon excitations
and, hence, to derive a new effective Hamiltonian. The approach developed here
is used for constructing a Boltzmann-type kinetic equation describing elastic
scattering of collective longitudinally polarized excitations in a gluon plasma
as well as the effect of the so-called nonlinear Landau damping. We have
performed detailed comparison of the effective amplitude of the plasmon-plasmon
interaction, which is determined using the classical Hamilton theory, with the
corresponding matrix element calculated in the framework of high-temperature
quantum chromodynamics; this has enabled us to determine applicability limits
for the purely classical approach described in this study.Comment: 21 pages, 2 figure
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