2,216 research outputs found
Classical Dimensional Transmutation and Confinement
We observe that probing certain classical field theories by external sources
uncovers the underlying renormalization group structure, including the
phenomenon of dimensional transmutation, at purely-classical level. We perform
this study on an example of theory and unravel asymptotic
freedom and triviality for negative and positives signs of
respectively. We derive exact classical function equation. Solving this
equation we find that an isolated source has an infinite energy and therefore
cannot exist as an asymptotic state. On the other hand a dipole, built out of
two opposite charges, has finite positive energy. At large separation the
interaction potential between these two charges grows indefinitely as a
distance in power one third
Sub-diffraction light propagation in fibers with anisotropic dielectric cores
We present a detailed study of light propagation in waveguides with
anisotropic metamaterial cores. We demonstrate that in contrast to conventional
optical fibers, our structures support free-space-like propagating modes even
when the waveguide radius is much smaller than the wavelength. We develop
analytical formalism to describe mode structure and propagation in strongly
anisotropic systems and study the effects related to waveguide boundaries and
material composition
Electron Glass Dynamics
Examples of glasses are abundant, yet it remains one of the phases of matter
whose understanding is very elusive. In recent years, remarkable experiments
have been performed on the dynamical aspects of glasses. Electron glasses offer
a particularly good example of the 'trademarks' of glassy behavior, such as
aging and slow relaxations. In this work we review the experimental literature
on electron glasses, as well as the local mean-field theoretical framework put
forward in recent years to understand some of these results. We also present
novel theoretical results explaining the periodic aging experiment.Comment: Invited review to appear in Annual Review of Condensed Matter Physic
Optimization of self-similar factor approximants
The problem is analyzed of extrapolating power series, derived for an
asymptotically small variable, to the region of finite values of this variable.
The consideration is based on the self-similar approximation theory. A new
method is suggested for defining the odd self-similar factor approximants by
employing an optimization procedure. The method is illustrated by several
examples having the mathematical structure typical of the problems in
statistical and chemical physics. It is shown that the suggested method
provides a good accuracy even when the number of terms in the perturbative
power series is small.Comment: Latex file, 16 page
The Dirac equation without spinors
In the first part of the paper we give a tensor version of the Dirac
equation. In the second part we formulate and analyse a simple model equation
which for weak external fields appears to have properties similar to those of
the 2--dimensional Dirac equation.Comment: 20 pages. Submitted for publication in the proceedings of the
conference `Functional analysis, partial differential equations and
applications', Rostock (Germany) 31 August--4 September 199
An Application of Caustics to Ultrasonic Defect Location
In this paper we describe a use of ultrasonic caustics to detect and locate defects in immersed rods and pipes.</p
Shocks and Universal Statistics in (1+1)-Dimensional Relativistic Turbulence
We propose that statistical averages in relativistic turbulence exhibit
universal properties. We consider analytically the velocity and temperature
differences structure functions in the (1+1)-dimensional relativistic
turbulence in which shock waves provide the main contribution to the structure
functions in the inertial range. We study shock scattering, demonstrate the
stability of the shock waves, and calculate the anomalous exponents. We comment
on the possibility of finite time blowup singularities.Comment: 37 pages, 7 figure
Results from the Relativistic Heavy Ion Collider
We describe the current status of the heavy ion research program at the
Relativistic Heavy Ion Collider (RHIC). The new suite of experiments and the
collider energies have opened up new probes of the medium created in the
collisions. Our review focuses on the experimental discoveries to date at RHIC
and their interpretation in the light of our present theoretical understanding
of the dynamics of relativistic heavy ion collisions and of the structure of
strongly interacting matter at high energy density.Comment: 47 pages, 10 figures, submitted to Annual Review of Nuclear and
Particle Science. The authors invite and appreciate feedback about possible
errors and/or inconsistencies in the manuscrip
Applicability of Taylor's hypothesis in thermally driven turbulence
In this paper, we show that in the presence of large-scale circulation (LSC),
Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal
convection using real space probes, a popular experimental tool. We perform
numerical simulation of turbulent convection in a cube and observe that the
velocity field follows Kolmogorov's spectrum (). We also record the
velocity time series using real space probes near the lateral walls. The
corresponding frequency spectrum exhibits Kolmogorov's spectrum (),
thus validating Taylor's hypothesis with the steady LSC playing the role of a
mean velocity field. The aforementioned findings based on real space probes
provide valuable inputs for experimental measurements used for studying the
spectrum of convective turbulence
Nuclear Matter and Nuclear Dynamics
Highlights on the recent research activity, carried out by the Italian
Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be
presented.Comment: Proceedings of the 12th Conference on Problems in Theoretical Nuclear
Physics, to appear in Journal of Physics, Conference Serie
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