11,511 research outputs found
Distinguished non-Archimedean representations
For a symmetric space (G,H), one is interested in understanding the vector
space of H-invariant linear forms on a representation \pi of G. In particular
an important question is whether or not the dimension of this space is bounded
by one. We cover the known results for the pair (G=R_{E/F}GL(n),H=GL(n)), and
then discuss the corresponding SL(n) case. In this paper, we show that
(G=R_{E/F}SL(n),H=SL(n)) is a Gelfand pair when n is odd. When is even, the
space of H-invariant forms on \pi can have dimension more than one even when
\pi is supercuspidal. The latter work is joint with Dipendra Prasad
Successful maternal and fetal outcome in an uncorrected case of tetralogy of fallot
Tetralogy of Fallot (ToF) is the most common congenital heart defect which is associated with systemic cyanosis. Pregnancy and delivery cause dramatic alterations in cardiovascular physiology and pregnancy in women with unrepaired TOF may have a worsening in right to left shunt with an increase of the cyanosis. This possesses an elevated risk of maternal and foetal morbidity and even mortality. We report and discuss a case of a 24 years old Primigravida with uncorrected ToF. A multidisciplinary team was involved in the management of the case with the aim to minimize maternal and foetal complications. The target of the management was to perform adequate maternal surveillance by maintaining an adequate oxygen saturation and good haemoglobin levels and perform timely foetal surveillance tests in the form of Obstetric doppler. A caesarean section was performed at 35 weeks and 5 days of gestation without any maternal or fetal complications. Without optimal obstetrical or medical management, prognosis of pregnancy in patient with uncorrected ToF is poor
SU(5) monopoles and non-abelian black holes
We construct spherically and axially symmetric monopoles in SU(5)
Yang-Mills-Higgs theory both in flat and curved space as well as spherical and
axial non-abelian, ''hairy'' black holes. We find that in analogy to the SU(2)
case, the flat space monopoles are either non-interacting (in the BPS limit) or
repelling. In curved space, however, gravity is able to overcome the repulsion
for suitable choices of the Higgs coupling constants and the gravitational
coupling. In addition, we confirm that indeed all qualitative features of
(gravitating) SU(2) monopoles are found as well in the SU(5) case. For the
non-abelian black holes, we compare the behaviour of the solutions in the BPS
limit with that for non-vanishing Higgs self-coupling constants.Comment: 14 Revtex pages, 9 PS-figure
A Monopole-Antimonopole Solution of the SU(2) Yang-Mills-Higgs Model
As shown by Taubes, in the Bogomol'nyi-Prasad-Sommerfield limit the SU(2)
Yang-Mills-Higgs model possesses smooth finite energy solutions, which do not
satisfy the first order Bogomol'nyi equations. We construct numerically such a
non-Bogomol'nyi solution, corresponding to a monopole-antimonopole pair, and
extend the construction to finite Higgs potential.Comment: 11 pages, including 4 eps figures, LaTex format using RevTe
Intermittency transitions to strange nonchaotic attractors in a quasiperiodically driven Duffing oscillator
Different mechanisms for the creation of strange nonchaotic attractors (SNAs)
are studied in a two-frequency parametrically driven Duffing oscillator. We
focus on intermittency transitions in particular, and show that SNAs in this
system are created through quasiperiodic saddle-node bifurcations (Type-I
intermittency) as well as through a quasiperiodic subharmonic bifurcation
(Type-III intermittency). The intermittent attractors are characterized via a
number of Lyapunov measures including the behavior of the largest nontrivial
Lyapunov exponent and its variance as well as through distributions of
finite-time Lyapunov exponents. These attractors are ubiquitous in
quasiperiodically driven systems; the regions of occurrence of various SNAs are
identified in a phase diagram of the Duffing system.Comment: 24 pages, RevTeX 4, 12 EPS figure
The BPS Domain Wall Solutions in Self-Dual Chern-Simons-Higgs Systems
We study domain wall solitons in the relativistic self-dual Chern-Simons
Higgs systems by the dimensional reduction method to two dimensional spacetime.
The Bogomolny bound on the energy is given by two conserved quantities in a
similar way that the energy bound for BPS dyons is set in some Yang-Mills-Higgs
systems in four dimensions. We find the explicit soliton configurations which
saturate the energy bound and their nonrelativistic counter parts. We also
discuss the underlying N=2 supersymmetry.Comment: 16 pages, LaTeX, no figure, a minor change in acknowledgment
Monopoles, Antimonopoles and Vortex Rings
We present a new class of static axially symmetric solutions of SU(2)
Yang-Mills-Higgs theory, where the Higgs field vanishes on rings centered
around the symmetry axis. Associating a magnetic dipole moment with each Higgs
vortex ring, the dipole moments add for solutions in the trivial topological
sector, whereas they cancel for magnetically charged solutions.Comment: 4 pages, 1 figur
Periodic ground state for the charged massive Schwinger model
It is shown that the charged massive Schwinger model supports a periodic
vacuum structure for arbitrary charge density, similar to the common
crystalline layout known in solid state physics. The dynamical origin of the
inhomogeneity is identified in the framework of the bozonized model and in
terms of the original fermionic variables.Comment: 19 pages, 10 figures, revised version, accepted in Phys. Rev.
A Simple Quantum Computer
We propose an implementation of a quantum computer to solve Deutsch's
problem, which requires exponential time on a classical computer but only
linear time with quantum parallelism. By using a dual-rail qubit representation
as a simple form of error correction, our machine can tolerate some amount of
decoherence and still give the correct result with high probability. The design
which we employ also demonstrates a signature for quantum parallelism which
unambiguously delineates the desired quantum behavior from the merely
classical. The experimental demonstration of our proposal using quantum optical
components calls for the development of several key technologies common to
single photonics.Comment: 8 pages RevTeX + 6 figures in postscrip
Thermal Equation of State of Tantalum
We have investigated the thermal equation of state of tantalum from first
principles using the Linearized Augmented Plane Wave (LAPW) and pseudopotential
methods for pressures up to 300 GPa and temperatures up to 10000 K. The
equation of state at zero temperature was computed using LAPW. For finite
temperatures, mixed basis pseudopotential computations were performed for 54
atom supercells. The vibrational contributions were obtained by computing the
partition function using the particle in a cell model, and the the finite
temperature electronic free energy was obtained from the LAPW band structures.
We discuss the behavior of thermal equation of state parameters such as the
Gr\"uneisen parameter , , the thermal expansivity , the
Anderson-Gr\"uneisen parameter as functions of pressure and
temperature. The calculated Hugoniot shows excellent agreement with shock-wave
experiments. An electronic topological transition was found at approximately
200 GPa
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