3,138 research outputs found
Gauge field theory for Poincar\'{e}-Weyl group
On the basis of the general principles of a gauge field theory the gauge
theory for the Poincar\'{e}-Weyl group is constructed. It is shown that tetrads
are not true gauge fields, but represent functions from true gauge fields:
Lorentzian, translational and dilatational ones. The equations of gauge fields
which sources are an energy-momentum tensor, orbital and spin momemta, and also
a dilatational current of an external field are obtained. A new direct
interaction of the Lorentzian gauge field with the orbital momentum of an
external field appears, which describes some new effects. Geometrical
interpretation of the theory is developed and it is shown that as a result of
localization of the Poincar\'{e}-Weyl group spacetime becomes a Weyl-Cartan
space. Also the geometrical interpretation of a dilaton field as a component of
the metric tensor of a tangent space in Weyl-Cartan geometry is proposed.Comment: LaTex, 27 pages, no figure
Stringy effect of the holographic correspondence for Dp-brane backgrounds
Based on the holographic conjecture for superstrings on Dp-brane backgrounds
and the dual (p+1)-dimensional gauge theory () given in
hep-th/0308024 and hep-th/0405203, we continue the study of superstring
amplitudes including string higher modes (). We give a prediction to
the two-point functions of operators with large R-charge J. The effect of
stringy modes do not appear as the form of anomalous dimensions except for p=3.
Instead, it gives non-trivial correction to the two-point functions for
supergravity modes. For p=4, the scalar two-point functions for any n behave
like free fields of the effective dimension d_{eff}=6 in the infra-red limit.Comment: 23 pages, typos correcte
Proper Motions and CCD-photometry of Stars in the Region of the Open Cluster Trumpler 2
The results of the complex study of galactic open cluster Trumpler 2 are
presented. In order to obtain the proper motions the positions of 2600 stars up
to the limit magnitude B ~ 16.25 mag in the area 80x80 arcmin around the
cluster were measured on 6 plates with the maximal epoch difference of 63
years. The root-mean error of the relative proper motions is 4.2 mas/yr. The
catalogue of BV magnitudes of all the stars in the investigated area was
compiled. Astrometric selection of the cluster members within the region of
R<16 arcmin from the center of the cluster was made by means of the W.Sanders
method. In that field 192 stars were found to have the individual membership
probability greater then 85%, 148 of them are situated within the
+/-3sigma_(B-V) band around the main sequence of the cluster. They are
considered to be cluster members by two criteria. The U-B ~ B-V diagram plotted
for the astrometrical cluster members by the data taken from the Washington
catalogue of the UBV photometry in the galactic cluster fields (Hoag et
al.1961) made it possible to redefine the value of the color excess E(B-V)=0.40
mag. The superposition of the MS of the cluster with the ZAMS Schmidt-Kaler
leads to the coincidence at the value of the apparent distance module
(V-Mv)=10.50 which corresponds to the distance r=725 pc. The luminosity and
mass functions of the Trumpler 2 were constructed and the value of the slope
Gamma=-1.90+/-0.22 was determined. The cluster age of 8.913x10^7 yr was
determined. It is shown that the red giant on the late stage of the evolution
(st N.1095) belongs to cluster and indicates the brightness variability. The
possibility that the number of both known and recently discovered variables are
cluster members was considered. Tables 2,3,3A,5 will be only available in the
electronic form.Comment: 14 pages, 7 figure
Supersymmetry of Tensionless Rotating Strings in AdS_5 x S^5, and Nearly-BPS Operators
It is shown that a class of rotating strings in AdS_5 x S^5 with SO(6)
angular momenta (J,J',J') preserve 1/8-supersymmetry for large J,J', in which
limit they are effectively tensionless; when J=0, supersymmetry is enhanced to
1/4. These results imply that recent checks of the AdS/CFT correspondence
actually test a nearly-BPS sector.Comment: 12 pages, no figures; v2: new section on CFT operators and new
references added, discussion section and acknowledgements modified, abstract
rephrashe
A note on spin chain/string duality
Recently a significant progress in matching the anomalous dimensions of
certain class of operators in N=4 SYM theory and rotating strings was made. The
correspondence was established mainly using Bethe ansatz technique applied to
the spin s Heisenberg model. In a recent paper Kruczenski (hep-th/0311203)
suggested to solve the Heisenberg model by using of sigme model approach. In
this paper we generalize the solutions obtained by Kruczenski and comment on
the dual string theory. It turns out that our solutions are related to the so
called Neumann-Rosochatius integrable system. We comment on the spin chain
solutions and on the string/gauge theory correspondence.Comment: v.2 One reference added, typos corrected, 21 page
Spiky Strings, Giant Magnons and beta-deformations
We study rigid string solutions rotating on the S^3 subspace of the
beta-deformed AdS_5xS^5 background found by Lunin and Maldacena. For particular
values of the parameters of the solutions we find the known giant magnon and
single spike strings. We present a single spike string solution on the deformed
S^3 and find how the deformation affects the dispersion relation. The possible
relation of this string solution to spin chains and the connection of the
solutions on the undeformed S^3 to the sine-Gordon model are briefly discussed.Comment: 20 pages, 2 figures; v2: typos corrected, references adde
Energy-Spin Trajectories in AdS_5 x S^5 from Semiclassical Vertex Operators
We study the relation between vertex operators in AdS_5 x S^5 and classical
spinning string solutions. In the limit of large quantum numbers the treatment
of vertex operators becomes semiclassical. In this regime, a given vertex
operator carrying a certain set of quantum numbers defines a singular solution.
We show in a number of examples that this solution coincides with the classical
string solution with the same quantum numbers but written in a different
two-dimensional coordinate system. The marginality condition imposed on an
operator yields a relation between the energy and the other quantum numbers
which is shown to coincide with that of the corresponding classical string
solution. We also argue that in some cases vertex operators in AdS_5 x S^5
cannot be given by expressions similar to the ones in flat space and a more
involved consideration is required.Comment: 23 pages, 1 Figur
Integrable Spin Chains with U(1)^3 symmetry and generalized Lunin-Maldacena backgrounds
We consider the most general three-state spin chain with U(1)^3 symmetry and
nearest neighbour interaction. Our model contains as a special case the spin
chain describing the holomorphic three scalar sector of the three parameter
complex deformation of N=4 SYM, dual to type IIB string theory in the
generalized Lunin-Maldacena backgrounds discovered by Frolov. We formulate the
coordinate space Bethe ansatz, calculate the S-matrix and determine for which
choices of parameters the S-matrix fulfills the Yang-Baxter equations. For
these choices of parameters we furthermore write down the R-matrix. We find in
total four classes of integrable models. In particular, each already known
model of the above type is nothing but one in a family of such models.Comment: 16 pages, 3 figures, references correcte
Precision Spectroscopy of AdS/CFT
We extend recent remarkable progress in the comparison of the dynamical
energy spectrum of rotating closed strings in AdS_5xS^5 and the scaling weights
of the corresponding non-near-BPS operators in planar N=4 supersymmetric gauge
theory. On the string side the computations are feasible, using semiclassical
methods, if angular momentum quantum numbers are large. This results in a
prediction of gauge theory anomalous dimensions to all orders in the `t Hooft
coupling lambda. On the gauge side the direct computation of these dimensions
is feasible, using a recently discovered relation to integrable (super) spin
chains, provided one considers the lowest order in lambda. This one-loop
computation then predicts the small-tension limit of the string spectrum for
all (i.e. small or large) quantum numbers. In the overlapping window of large
quantum numbers and small effective string tension, the string theory and gauge
theory results are found to match in a mathematically highly non-trivial
fashion. In particular, we compare energies of states with (i) two large
angular momenta in S^5, and (ii) one large angular momentum in AdS_5 and S^5
each, and show that the solutions are related by an analytic continuation.
Finally, numerical evidence is presented on the gauge side that the agreement
persists also at higher (two) loop order.Comment: 26 pages, 1 figure, v2: typos correcte
Formation of the Upstream Region in HV Gas Blast Interrupters with Synchronous Gas Injection
The problem of a synchronous gas injection at the vicinity of current zero for high voltage gas blast circuit breakers~(GCB) is discussed. The basic aim of the investigation is to improve the efficiency of arc quenching in GCB by increasing interruption ability without changes in drive parameters. The paper reviews the upstream region influence on the interruption capability, gas injection - mass flow interactions at the region between electrical contact and nozzle throat of GCB. Numerical simulation is used to calculate gas--dynamics parameters at the upstream region of mono--flow GCB. The mass discharged as a result of the synchronous gas injection can rapidly modify both the density and pressure at the nozzle throat, regulate flow velocity in the research region. The selected method of the gas injection effects the breaking performance in the arc quenching device strongly. Some calculation results are presented.
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