124 research outputs found
Electron cyclotron mass in undoped CdTe/CdMnTe quantum wells
Optically detected cyclotron resonance of two-dimensional electrons has been
studied in nominally undoped CdTe/(Cd,Mn)Te quantum wells. The enhancement of
carrier quantum confinement results in an increase of the electron cyclotron
mass from 0.099 to 0.112 with well width decreasing from 30 down to
3.6 nm. Model calculations of the electron effective mass have been performed
for this material system and good agreement with experimental data is achieved
for an electron-phonon coupling constant =0.32
Gauge invariance of dimension two condensate in Yang-Mills theory
Gauge independence of dimension two condensate in Yang-Mills theory is
demonstrated by using a noncommutative theory technique.Comment: 7 page
Color Confinement and Massive Gluons
Color confinement is one of the central issues in QCD so that there are
various interpretations of this feature. In this paper we have adopted the
interpretation that colored particles are not subject to observation just
because colored states are unphysical in the sense of Eq. (2.16). It is shown
that there are two phases in QCD distinguished by different choices of the
gauge parameter. In one phase, called the "confinement phase", color
confinement is realized and gluons turn out to be massive. In the other phase,
called the "deconfinement phase", color confinement is not realized, but the
gluons remain massless.Comment: 14 page
Interaction of electric charges in (2+1)D magnetic dipole gas
The interaction of electrically charged particles in a dilute gas of
point--like magnetic dipoles is studied. We show that the interaction potential
at small distances has a linear piece due to overlap of the dipole clouds
gathered near electric sources. At large distances the potential becomes of the
Coulomb type with non-perturbatively renormalized charge of the test particle.
The physical applications of these results are discussed.Comment: 23 pages, 12 EPS figures, RevTeX, uses epsfig.sty; misprints
corrected (to appear in Phys.Rev.D
The non-perturbative groundstate of Q.C.D and the local composite operator A_mu^2
We investigate the possibility that the dimension 2 condensate A_mu^2 has a
non zero non-perturbative value in Yang-Mills theory. We introduce a
multiplicatively renormalisable effective potential for this condensate and
show through two loop calculations that a non zero condensate is energetically
favoured.Comment: 12 page
Magnetic monopoles, alive
We review recent developments in understanding the physics of the magnetic
monopoles in unbroken non-Abelian gauge theories. Since numerical data on the
monopoles are accumulated in lattice simulations, the continuum theory is
understood as the limiting case of the lattice formulation. In this review,
written for a memorial volume dedicated to the memory of Academician A.B.
Migdal, we emphasize physical effects related to the monopoles. In particular,
we discuss the monopole-antimonopole potential at short and larger distances as
well as a dual formulation of the gluodynamics, relevant to the physics of the
confinement.Comment: 24+1 pp., Latex2e, no figure
Dimension two vacuum condensates in gauge-invariant theories
Gauge dependence of the dimension two condensate in Abelian and non-Abelian
Yang-Mills theory is investigated.Comment: 10 page
On the non-Abelian Stokes theorem for SU(2) gauge fields
We derive a version of non-Abelian Stokes theorem for SU(2) gauge fields in
which neither additional integration nor surface ordering are required. The
path ordering is eliminated by introducing the instantaneous color orientation
of the flux. We also derive the non-Abelian Stokes theorem on the lattice and
discuss various terms contributing to the trace of the Wilson loop.Comment: Latex2e, 0+14 pages, 3 figure
Radial distribution of a single-pass amplified radiation in the active elements of CuBr lasers
The paper presents the results of study of single-pass amplified radiation distribution of copper bromide vapor laser active elements used in high-speed laser monitors. The possibility of modifying the profile of a single-pass amplified light beam by changing the copper bromide vapor concentration is demonstrated. This means of influence on the radiation profile seems to be easiest due to implementation by varying only one parameter of operation. Gaussian, ring-shaped or flat profiles can be achieved depending on the temperature of the containers with copper bromide. The diameter of the beam becomes narrower when increasing the concentration of copper bromide vapor. This feature is characteristic of the discharge tubes as small (diameter 2.5, length 5 cm) and large (diameter 5 cm, length 90 cm) active volume
Physics of the Power Corrections in QCD
We review the physics of the power corrections to the parton model. In the
first part, we consider the power corrections which characterize the infrared
sensitivity of Feynman graphs when the contribution of short distances
dominates. The second part is devoted to the hypothetical power corrections
associated with nonperturbative effects at small distances.Comment: 35 pages, 6 figures. Lecture given by V.I.Zakharov at the Winter
School of physics of ITEP, February 1999. Minor corrections, references adde
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