9,431 research outputs found
Partially composite 2-Higgs-doublet model
In the extra dimensional scenarios with gauge fields in the bulk, the
Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type
attractive four-fermion interactions, which can break electroweak symmetry
dynamically with accompanying composite Higgs fields. We consider a possibility
that electroweak symmetry breaking (EWSB) is triggered by both a fundamental
Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism
induced by a new strong dynamics. The resulting Higgs sector is a partially
composite two-Higgs doublet model with specific boundary conditions on the
coupling and mass parameters originating at a compositeness scale .
The phenomenology of this model is discussed including the collider
phenomenology at LHC and ILC.Comment: To appear in the proceeding of LCWS06, Bangalore, Indi
Out of plane optical conductivity in d-wave superconductors
We study theoretically the out of plane optical conductivity of d-wave
superconductors in the presence of impurities at T=0K. Unlike the usual
approach, we assume that the interlayer quasi-particle transport is due to
coherent tunneling. The present model describes the T^2 dependence of the out
of plane superfluid density observed in YBCO and Tl2201 for example. In the
optical conductivity there is no Drude peak in agreement with experiment, and
the interlayer Josephson tunneling is also assured in this model. In the
unitary limit we predict a step like behaviour around omega=Delta in both the
real and imaginary part of the optical conductivity.Comment: 7 pages, 7 figure
The magnetic field dependence of the threshold electric field in unconventional charge density waves
Many experiments suggest that the unidentified low temperature phase (LTP) of
alpha-(BEDT-TTF)_2KHg(SCN)_4 is most likely unconventional charge density wave
(UCDW). To further this identification we present our theoretical study of the
threshold electric field of UCDW in a magnetic field. The magnetic
field-temperature phase diagram is very similar to those in a d-wave
superconductor. We find a rather strong field dependence of the threshold
electric field, which should be readily accessible experimentally.Comment: 7 pages, 6 figure
Novel vortex lattice transition in d-wave superconductors
We study the vortex state in a magnetic field parallel to the axis in the
framework of the extended Ginzburg Landau equation. We find the vortex acquires
a fourfold modulation proportional to where is the angle
makes with the -axis. This term gives rise to an attractive
interaction between two vortices when they are aligned parallel to or
. We predict the first order vortex lattice transition at
from triangular into the square lattice
tilted by from the axis. This gives the critical field
a few Tesla for YBCO and Bi2212 monocrystals at low temperatures ().Comment: 6 pages, 4 figure
The Dynamical Behaviors in (2+1)-Dimensional Gross-Neveu Model with a Thirring Interaction
We analyze (2+1)-dimensional Gross-Neveu model with a Thirring interaction,
where a vector-vector type four-fermi interaction is on equal terms with a
scalar-scalar type one. The Dyson-Schwinger equation for fermion self-energy
function is constructed up to next-to-leading order in 1/N expansion. We
determine the critical surface which is the boundary between a broken phase and
an unbroken one in () space. It is observed that the
critical behavior is mainly controlled by Gross-Neveu coupling and
the region of the broken phase is separated into two parts by the line
. The mass function is strongly
dependent upon the flavor number N for , while weakly for
, the critical flavor number
increases as Thirring coupling decreases. By driving the CJT
effective potential, we show that the broken phase is energetically preferred
to the symmetric one. We discuss the gauge dependence of the mass function and
the ultra-violet property of the composite operators.Comment: 19 pages, LaTex, 6 ps figure files(uuencoded in seperate file
Exact solutions of charged wormhole
In this paper, the backreaction to the traversable Lorentzian wormhole
spacetime by the scalar field or electric charge is considered to find the
exact solutions. The charges play the role of the additional matter to the
static wormhole which is already constructed by the exotic matter. The
stability conditions for the wormhole with scalar field and electric charge are
found from the positiveness and flareness for the wormhole shape function.Comment: 9 pages, Revtex, no figures, to appear in Phys. Rev. D(2001
Singularity of the Vortex Density of States in d-wave Superconductors
In d-wave superconductors, the electronic density of states (DOS) induced by
a vortex exhibits 1/|E| divergency at low energies. It is the result of gap
nodes in the excitations spectrum outside the vortex core. The heat capacity in
two regimes, (T/T_c)^2 >> B/B_{c2} and (T/T_c)^2 << B/B_{c2}, is discussed.Comment: LaTeX file, 8 pages, no figures, submitted to JETP Letter
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