226 research outputs found
On p-Adic Sector of Adelic String
We consider construction of Lagrangians which are candidates for p-adic
sector of an adelic open scalar string. Such Lagrangians have their origin in
Lagrangian for a single p-adic string and contain the Riemann zeta function
with the d'Alembertian in its argument. In particular, we present a new
Lagrangian obtained by an additive approach which takes into account all p-adic
Lagrangians. The very attractive feature of this new Lagrangian is that it is
an analytic function of the d'Alembertian. Investigation of the field theory
with Riemann zeta function is interesting in itself as well.Comment: 10 pages. Presented at the 2nd Conf. on SFT and Related Topics,
Moscow, April 2009. Submitted to Theor. Math. Phy
Nonlocal Dynamics of p-Adic Strings
We consider the construction of Lagrangians that might be suitable for
describing the entire -adic sector of an adelic open scalar string. These
Lagrangians are constructed using the Lagrangian for -adic strings with an
arbitrary prime number . They contain space-time nonlocality because of the
d'Alembertian in argument of the Riemann zeta function. We present a brief
review and some new results.Comment: 8 page
p-Adic and Adelic Harmonic Oscillator with Time-Dependent Frequency
The classical and quantum formalism for a p-adic and adelic harmonic
oscillator with time-dependent frequency is developed, and general formulae for
main theoretical quantities are obtained. In particular, the p-adic propagator
is calculated, and the existence of a simple vacuum state as well as adelic
quantum dynamics is shown. Space discreteness and p-adic quantum-mechanical
phase are noted.Comment: 10 page
Zeta Nonlocal Scalar Fields
We consider some nonlocal and nonpolynomial scalar field models originated
from p-adic string theory. Infinite number of spacetime derivatives is
determined by the operator valued Riemann zeta function through d'Alembertian
in its argument. Construction of the corresponding Lagrangians L starts
with the exact Lagrangian for effective field of p-adic tachyon
string, which is generalized replacing p by arbitrary natural number n and then
taken a sum of over all n. The corresponding new objects we
call zeta scalar strings. Some basic classical field properties of these fields
are obtained and presented in this paper. In particular, some solutions of the
equations of motion and their tachyon spectra are studied. Field theory with
Riemann zeta function dynamics is interesting in its own right as well.Comment: 13 pages, submitted to Theoretical and Mathematical Physic
p-Adic Mathematical Physics
A brief review of some selected topics in p-adic mathematical physics is
presented.Comment: 36 page
Analysis of scalar perturbations in cosmological models with a non-local scalar field
We develop the cosmological perturbations formalism in models with a single
non-local scalar field originating from the string field theory description of
the rolling tachyon dynamics. We construct the equation for the energy density
perturbations of the non-local scalar field in the presence of the arbitrary
potential and formulate the local system of equations for perturbations in the
linearized model when both simple and double roots of the characteristic
equation are present. We carry out the general analysis related to the
curvature and entropy perturbations and consider the most specific example of
perturbations when important quantities in the model become complex.Comment: LaTeX, 25 pages, 1 figure, v2: Subsection 3.2 and Section 5 added,
references added, accepted for publication in Class. Quant. Grav. arXiv admin
note: text overlap with arXiv:0903.517
Towards a Resolution of the Cosmological Singularity in Non-local Higher Derivative Theories of Gravity
One of the greatest problems of standard cosmology is the Big Bang
singularity. Previously it has been shown that non-local ghostfree
higher-derivative modifications of Einstein gravity in the ultra-violet regime
can admit non-singular bouncing solutions. In this paper we study in more
details the dynamical properties of the equations of motion for these theories
of gravity in presence of positive and negative cosmological constants and
radiation. We find stable inflationary attractor solutions in the presence of a
positive cosmological constant which renders inflation {\it geodesically
complete}, while in the presence of a negative cosmological constant a cyclic
universe emerges. We also provide an algorithm for tracking the super-Hubble
perturbations during the bounce and show that the bouncing solutions are free
from any perturbative instability.Comment: 38 pages, 6 figures. V2: Added: a word to the title, clarifications,
an appendix, many references. To appear in JCA
Large Nongaussianity from Nonlocal Inflation
We study the possibility of obtaining large nongaussian signatures in the
Cosmic Microwave Background in a general class of single-field nonlocal
hill-top inflation models. We estimate the nonlinearity parameter f_{NL} which
characterizes nongaussianity in such models and show that large nongaussianity
is possible. For the recently proposed p-adic inflation model we find that
f_{NL} ~ 120 when the string coupling is order unity. We show that large
nongaussianity is also possible in a toy model with an action similar to those
which arise in string field theory.Comment: 27 pages, no figures. Added references and some clarifying remark
Derivation of the Boltzmann equation and entropy production in functional mechanics
A derivation of the Boltzmann equation from the Liouville equation by the use
of the Grad limiting procedure in a finite volume is proposed. We introduce two
scales of space-time: macro- and microscale and use the BBGKY hierarchy and the
functional formulation of classical mechanics. According to the functional
approach to mechanics, a state of a system of particles is formed from the
measurements, which are rational numbers. Hence, one can speak about the
accuracy of the initial probability density function in the Liouville equation.
We assume that the initial data for the microscopic density functions are
assigned by the macroscopic one (so, one can say about a kind of hierarchy and
subordination of the microscale to the macroscale) and derive the Boltzmann
equation, which leads to the entropy production.Comment: 14 page
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