203 research outputs found
Hamiltonian Embedding of SU(2) Higgs Model in the Unitary Gauge
Following systematically the generalized Hamiltonian approach of Batalin,
Fradkin and Tyutin (BFT), we embed the second-class non-abelian SU(2) Higgs
model in the unitary gauge into a gauge invariant theory. The strongly
involutive Hamiltonian and constraints are obtained as an infinite power series
in the auxiliary fields. Furthermore, comparing these results with those
obtained from the gauged second class Lagrangian, we arrive at a simple
interpretation for the first class Hamiltonian, constraints and observables.Comment: 13 pages, Latex, no figure
Symplectic quantization of self-dual master Lagrangian
We consider the master Lagrangian of Deser and Jackiw, interpolating between
the self-dual and the Maxwell-Chern-Simons Lagrangian, and quantize it
following the symplectic approach, as well as the traditional Dirac scheme. We
demonstrate the equivalence of these procedures in the subspace of the
second-class constraints. We then proceed to embed this mixed first- and
second-class system into an extended first-class system within the framework of
both approaches, and construct the corresponding generator for this extended
gauge symmetry in both formulations.Comment: 27 page
Batalin-Tyutin Quantization of the Self-Dual Massive Theory in Three Dimensions
We quantize the self-dual massive theory by using the Batalin-Tyutin
Hamiltonian method, which systematically embeds second class constraint system
into first class one in the extended phase space by introducing the new fields.
Through this analysis we obtain simultaneously the St\"uckelberg scalar term
related to the explicit gauge-breaking effect and the new type of Wess-Zumino
action related to the Chern-Simons term.Comment: 17 pages, SOGANG-HEP 191/9
Flavor symmetry breaking effects on SU(3) Skyrmion
We study the massive SU(3) Skyrmion model to investigate the flavor symmetry
breaking (FSB) effects on the static properties of the strange baryons in the
framework of the rigid rotator quantization scheme combined with the improved
Dirac quantization one. Both the chiral symmetry breaking pion mass and FSB
kinetic terms are shown to improve the ratio of the strange-light to
light-light interaction strengths and that of the strange-strange to
light-light.Comment: 12 pages, latex, no figure
Ab initio study of thallium nanoclusters on Si(111)-7x7
We have studied the stability of a thallium nanocluster of various numbers of atoms (N=1,2,...,10) on a Si(111)-7x7 substrate using density functional theory total energy calculations. We have compared it with clusters of other group III elements (Al, Ga, and In). Thallium is found to be unstable with the triangular cluster, which has been known to be stable for other group III elements. Instead, a slightly different structure, in which Si atop atoms are lower than thallium atoms in height by 2.56 angstrom, was found to be quite stable. Such an abnormal structure originates from the inert pair of 6s(2) electrons due to the significant spin-orbit interaction. The initial relaxed N=6 Tl cluster continues to grow with increasing N up to N=9 in the faulted-half unit cell, which is consistent with experimental observationsclose121
Operator Ordering Problem of the Nonrelativistic Chern-Simons Theory
The operator ordering problem due to the quantization or regularization
ambiguity in the Chern-Simons theory exists. However, we show that this can be
avoided if we require Galilei covariance of the nonrelativistic Abelian
Chern-Simons theory even at the quantum level for the extended sources. The
covariance can be recovered only by choosing some particular operator orderings
for the generators of the Galilei group depending on the quantization
ambiguities of the commutation relation. We show that the
desired ordering for the unusual prescription is not the same as the well-known
normal ordering but still satisfies all the necessary conditions. Furthermore,
we show that the equations of motion can be expressed in a similar form
regardless of the regularization ambiguity. This suggests that the different
regularization prescriptions do not change the physics. On the other hand, for
the case of point sources the regularization prescription is uniquely
determined, and only the orderings, which are equivalent to the usual one, are
allowed.Comment: 18 page
Dilaton gravity approach to three dimensional Lifshitz black hole
The z=3 Lifshitz black hole is an exact black hole solution to the new
massive gravity in three dimensions. In order to understand this black hole
clearly, we perform a dimensional reduction to two dimensional dilaton gravity
by utilizing the circular symmetry. Considering the linear dilaton, we find the
same Lifshitz black hole in two dimensions. This implies that all thermodynamic
quantities of the z=3 Lifshitz black hole could be obtained from its
corresponding black hole in two dimensions. As a result, we derive the
temperature, mass, heat capacity, Bekesnstein-Hawking entropy, and free energy.Comment: 13 pages, 1 figure, version to appear in EPJ
Quasinormal modes from potentials surrounding the charged dilaton black hole
We clarify the purely imaginary quasinormal frequencies of a massless scalar
perturbation on the 3D charged-dilaton black holes. This case is quite
interesting because the potential-step appears outside the event horizon
similar to the case of the electromagnetic perturbations on the large
Schwarzschild-AdS black holes. It turns out that the potential-step type
provides the purely imaginary quasinormal frequencies, while the
potential-barrier type gives the complex quasinormal modes.Comment: 19 pages, 8 figure
Effects of annealing treatment prior to cold rolling on delayed fracture properties in ferrite-austenite duplex lightweight steels
Tensile properties of recently developed automotive high-strength steels containing about 10 wt pct of Mn and Al are superior to other conventional steels, but the active commercialization has been postponed because they are often subjected to cracking during formation or to the delayed fracture after formation. Here, the delayed fracture behavior of a ferrite-austenite duplex lightweight steel whose microstructure was modified by a batch annealing treatment at 1023 K (750 A degrees C) prior to cold rolling was examined by HCl immersion tests of cup specimens, and was compared with that of an unmodified steel. After the batch annealing, band structures were almost decomposed as strong textures of {100}aOE (c) 011 > alpha-fibers and {111}aOE (c) 112 > gamma-fibers were considerably dissolved, while ferrite grains were refined. The steel cup specimen having this modified microstructure was not cracked when immersed in an HCl solution for 18 days, whereas the specimen having unmodified microstructure underwent the delayed fracture within 1 day. This time delayed fracture was more critically affected by difference in deformation characteristics such as martensitic transformation and deformation inhomogeneity induced from concentration of residual stress or plastic strain, rather than the difference in initial microstructures. The present work gives a promise for automotive applications requiring excellent mechanical and delayed fracture properties as well as reduced specific weight.ope
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