4,679 research outputs found
Wavefunctional approach to the bilayer \nu =1 system and a possibility for a double non-chiral pseudospin liquid
We systematically discuss candidate wave functions for the ground state of
the bilayer \nu = 1 as the distance between the layers is varied. Those that
describe increased intralayer correlations at finite distance show a departure
from the superflid description for smaller distances. They may support finite
energy meron excitations and a dissipative collective mode in the place of the
Goldstone mode of the ordered phase i.e. describe a vortex metal phase, or
imply even an incompressible, pseudospin liquid, behavior. Therefore they
describe possible outcomes of quantum disordering at finite distance between
the layers. The vortex metal phase may show up in experiments in the presence
of disorder at lower temperatures and explain the observed "imperfect
superfluidity", and the pseudospin liquid phase may be the cause of the
thermally activated (gapped) behavior of the longitudinal and Hall resistances
at higher temperatures in counterflow experiments.Comment: 10 pages, 4 figure
Relativistic Effects in Extrasolar Planetary Systems
This paper considers general relativistic (GR) effects in currently observed
extrasolar planetary systems. Although GR corrections are small, they can
compete with secular interactions in these systems and thereby play an
important role. Specifically, some of the observed multiple planet systems are
close to secular resonance, where the dynamics is extremely sensitive to GR
corrections, and these systems can be used as laboratories to test general
relativity. For the three-planet solar system Upsilon Andromedae, secular
interaction theory implies an 80% probability of finding the system with its
observed orbital elements if GR is correct, compared with only a 2% probability
in the absence of GR. In the future, tighter constraints can be obtained with
increased temporal coverage.Comment: Accepted for publication in International Journal of Modern Physics
D; this paper received ``Honorable Mention'' in the 2006 Essay Competition of
the Gravity Research Foundation; 9 pages including 1 figur
Pairing via Index theorem
This work is motivated by a specific point of view: at short distances and
high energies the undoped and underdoped cuprates resemble the -flux phase
of the t-J model. The purpose of this paper is to present a mechanism by which
pairing grows out of the doped -flux phase. According to this mechanism
pairing symmetry is determined by a parameter controlling the quantum tunneling
of gauge flux quanta. For zero tunneling the symmetry is ,
while for large tunneling it is . A zero-temperature critical
point separates these two limits
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