1,269 research outputs found
A quantum volume hologram
We propose a new scheme for parallel spatially multimode quantum memory for
light. The scheme is based on counter-propagating quantum signal wave and
strong classical reference wave, like in a classical volume hologram, and
therefore can be called a quantum volume hologram. The medium for the hologram
consists of a spatially extended ensemble of atoms placed in a magnetic field.
The write-in and read-out of this quantum hologram is as simple as that of its
classical counterpart and consists of a single pass illumination. In addition
we show that the present scheme for a quantum hologram is less sensitive to
diffraction and therefore is capable of achieving higher density of storage of
spatial modes as compared to previous proposals. A quantum hologram capable of
storing entangled images can become an important ingredient in quantum
information processing and quantum imaging.Comment: 8 pages, 2 figure
Post-Socialist Transformation of Central and Eastern Europe at the Turn of the Century: Regional Development and Economic Inequality
The evolution of socio-economic systems is non-linear, it includes both the periods of smooth changes and subsequent abrupt transformational leaps. The overall structure of new prospects opens as early as at the stage of emerging evolutionary processes, and their forecast requires to analyze the historical premises and risks that are closely associated with the change of public attitudes. With the collapse of the Soviet Union, the newly independent states went through a transformational and evolutionary development stage that led them from a regional economy (since they actually had been the regions) to the national economy, while the countries in Central and Eastern Europe experienced a dramatic drift towards the European Union. This paper examines the results of almost 25-year-long transformation of these countries. The new states that emerged following the collapse of the Soviet Union went through three types of transformation. First, there were transformations on the ideological level. The transformations of the second type were purely economic. The third type can be described as institutional (including structural and financial) transformation. It has been demonstrated that one of the important reasons for modest economic performance in the post-Soviet space was the fact that the new states ignored and did not use the principles of regional policy and regional modernization in their state-building practice. A characteristic feature in the socio-economic evolution of Eastern Europe after 1990 was a sharply emphasized process of stratification and social differentiation occurring against the backdrop of insufficiently strong middle class and the polarization of income levels in different regions. The growing polarization of income levels in different regions represents the dominant trend of rising economic inequality.This research has been conducted with the support of the Russian Science Foundation (the Grant No. 14–28–00065) "Structural and Cyclical Paradigm of Economic and Technological Renewal of Macro-Social Systems (World and Russia in the First Half of the 21st century).
Plasma dispersion of multisubband electron systems over liquid helium
Density-density response functions are evaluated for nondegenerate
multisubband electron systems in the random-phase approximation for arbitrary
wave number and subband index. We consider both quasi-two-dimensional and
quasi-one- dimensional systems for electrons confined to the surface of liquid
helium. The dispersion relations of longitudinal intrasubband and transverse
intersubband modes are calculated at low temperatures and for long wavelengths.
We discuss the effects of screening and two-subband occupancy on the plasmon
spectrum. The characteristic absorption edge of the intersubband modes is
shifted relatively to the single-particle intersubband separation and the
depolarization shift correction can be significant at high electron densities
Understanding Anomalous Transport in Intermittent Maps: From Continuous Time Random Walks to Fractals
We show that the generalized diffusion coefficient of a subdiffusive
intermittent map is a fractal function of control parameters. A modified
continuous time random walk theory yields its coarse functional form and
correctly describes a dynamical phase transition from normal to anomalous
diffusion marked by strong suppression of diffusion. Similarly, the probability
density of moving particles is governed by a time-fractional diffusion equation
on coarse scales while exhibiting a specific fine structure. Approximations
beyond stochastic theory are derived from a generalized Taylor-Green-Kubo
formula.Comment: 4 pages, 3 eps figure
Diffraction and quasiclassical limit of the Aharonov--Bohm effect
Since the Aharonov-Bohm effect is the purely quantum effect that has no
analogues in classical physics, its persistence in the quasiclassical limit
seems to be hardly possible. Nevertheless, we show that the scattering
Aharonov-Bohm effect does persist in the quasiclassical limit owing to the
diffraction, i.e. the Fraunhofer diffraction in the case when space outside the
enclosed magnetic flux is Euclidean, and the Fresnel diffraction in the case
when the outer space is conical. Hence, the enclosed magnetic flux can serve as
a gate for the propagation of short-wavelength, almost classical, particles. In
the case of conical space, this quasiclassical effect which is in principle
detectable depends on the particle spin.Comment: 12 pages, minor changes, references update
Hyperfine Level Splitting for Hydrogen-Like Ions due to Rotation-Spin Coupling
The theoretical aspects of spin-rotation coupling are presented. The approach
is based on the general covariance principle. It is shown that the
gyrogravitational ratio of the bare spin-1/2 and the spin-1 particles is equal
unity. That is why spin couples with rotation as an ordinary angular momentum.
This result is the rigorous substantiation of the cranking model. To observe
the phenomenon, the experiment with hydrogen-like ions in a storage ring is
suggested. It is found that the splitting of the
hyperfine state of the and ions
circulating in the storage ring ESR in Darmstadt along a helical trajectory is
about 4.5 MHz. We argue that such splitting can be experimentally determined by
means of the ionic interferometry.Comment: 6 pages, final versio
Pseudo-epsilon expansion and the two-dimensional Ising model
Starting from the five-loop renormalization-group expansions for the
two-dimensional Euclidean scalar \phi^4 field theory (field-theoretical version
of two-dimensional Ising model), pseudo-\epsilon expansions for the Wilson
fixed point coordinate g*, critical exponents, and the sextic effective
coupling constant g_6 are obtained. Pseudo-\epsilon expansions for g*, inverse
susceptibility exponent \gamma, and g_6 are found to possess a remarkable
property - higher-order terms in these expansions turn out to be so small that
accurate enough numerical estimates can be obtained using simple Pade
approximants, i. e. without addressing resummation procedures based upon the
Borel transformation.Comment: 4 pages, 4 tables, few misprints avoide
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