10 research outputs found
Non-Localizability and Asymptotic Commutativity
The mathematical formalism commonly used in treating nonlocal highly singular
interactions is revised. The notion of support cone is introduced which
replaces that of support for nonlocalizable distributions. Such support cones
are proven to exist for distributions defined on the Gelfand-Shilov spaces
, where . This result leads to a refinement of previous
generalizations of the local commutativity condition to nonlocal quantum
fields. For string propagators, a new derivation of a representation similar to
that of K\"{a}llen-Lehmann is proposed. It is applicable to any initial and
final string configurations and manifests exponential growth of spectral
densities intrinsic in nonlocalizable theories.Comment: This version is identical to the initial one whose ps and pdf files
were unavailable, with few corrections of misprint
On The Universality Class Of Little String Theories
We propose that Little String Theories in six dimensions are quasilocal
quantum field theories. Such field theories obey a modification of Wightman
axioms which allows Wightman functions (i.e. vacuum expectation values of
products of fundamental fields) to grow exponentially in momentum space.
Wightman functions of quasilocal fields in x-space violate microlocality at
short distances. With additional assumptions about the ultraviolet behavior of
quasilocal fields, one can define approximately local observables associated to
big enough compact regions. The minimum size of such a region can be
interpreted as the minimum distance which observables can probe. We argue that
for Little String Theories this distance is of order {\sqrt N}/M_s.Comment: 25 pages, late
Bose-Einstein Condensation and Free DKP field
The thermodynamical partition function of the Duffin-Kemmer-Petiau theory is
evaluated using the imaginary-time formalism of quantum field theory at finite
temperature and path integral methods. The DKP partition function displays two
features: (i) full equivalence with the partition function for charged scalar
particles and charged massive spin 1 particles; and (ii) the zero mode sector
which is essential to reproduce the well-known relativistic Bose-Einstein
condensation for both theories.Comment: 12 pages, 2 eps figures. To be published in Physics Letter
Fermion Propagators in Type II Fivebrane Backgrounds
The fermion propagators in the fivebrane background of type II superstring
theories are calculated. The propagator can be obtained by explicitly
evaluating the transition amplitude between two specific NS-R boundary states
by the propagator operator in the non-trivial world-sheet conformal field
theory for the fivebrane background. The propagator in the field theory limit
can be obtained by using point boundary states. We can explicitly investigate
the lowest lying fermion states propagating in the non-trivial ten-dimensional
space-time of the fivebrane background: M^6 x W_k^(4), where W_k^(4) is the
group manifold of SU(2)_k x U(1). The half of the original supersymmetry is
spontaneously broken, and the space-time Lorentz symmetry SO(9,1) reduces to
SO(5,1) in SO(5,1) x SO(4) \subset SO(9,1) by the fivebrane background. We find
that there are no propagations of SO(4) (local Lorentz) spinor fields, which is
consistent with the arguments on the fermion zero-modes in the fivebrane
background of low-energy type II supergravity theories.Comment: 15 page
Approximate solution of the Duffin-Kemmer-Petiau equation for a vector Yukawa potential with arbitrary total angular momenta
The usual approximation scheme is used to study the solution of the
Duffin-Kemmer-Petiau (DKP) equation for a vector Yukawa potential in the
framework of the parametric Nikiforov-Uvarov (NU) method. The approximate
energy eigenvalue equation and the corresponding wave function spinor
components are calculated for arbitrary total angular momentum in closed form.
Further, the approximate energy equation and wave function spinor components
are also given for case. A set of parameter values is used to obtain the
numerical values for the energy states with various values of quantum levelsComment: 17 pages; Communications in Theoretical Physics (2012). arXiv admin
note: substantial text overlap with arXiv:1205.0938, and with
arXiv:quant-ph/0410159 by other author
The first dozen years of the history of ITEP Theoretical Physics Laboratory
The theoretical investigations at ITEP in the years 1945-1958 are reviewed.
There are exposed the most important theoretical results, obtained in the
following branches of physics: 1) the theory of nuclear reactors on thermal
neutrons; 2) the hydrogen bomb project ("Tube" in USSR and "Classical Super" in
USA); 3) radiation theory; ~4) low temperature physics; 5) quantum
electrodynamics and quantum field theories; 6) parity violation in weak
interactions, the theory of -decay and other weak processes; 7) strong
interaction and nuclear physics. To the review are added the English
translations of few papers, originally published in Russian, but unknown (or
almost unknown) to Western readers.Comment: 55 pages, 5 fig