121,486 research outputs found
Quantum-disordered slave-boson theory of underdoped cuprates
We study the stability of the spin gap phase in the U(1) slave-boson theory
of the t-J model in connection to the underdoped cuprates. We approach the spin
gap phase from the superconducting state and consider the quantum phase
transition of the slave-bosons at zero temperature by introducing vortices in
the boson superfluid. At finite temperatures, the properties of the bosons are
different from those of the strange metal phase and lead to modified gauge
field fluctuations. As a result, the spin gap phase can be stabilized in the
quantum critical and quantum disordered regime of the boson system. We also
show that the regime of quantum disordered bosons with the paired fermions can
be regarded as the strong coupling version of the recently proposed nodal
liquid theory.Comment: 5 pages, Replaced by the published versio
Estimation of Source- and Quality-Differentiated Import Demand Under Aggregate Import Quota: An Application to Japan's Wheat
International Relations/Trade,
Can one hear the shape of a population history?
Reconstructing past population size from present day genetic data is a major
goal of population genetics. Recent empirical studies infer population size
history using coalescent-based models applied to a small number of individuals.
Here we provide tight bounds on the amount of exact coalescence time data
needed to recover the population size history of a single, panmictic population
at a certain level of accuracy. In practice, coalescence times are estimated
from sequence data and so our lower bounds should be taken as rather
conservative.Comment: 22 pages, 7 figures; v2 is significantly revised from v
Interfacial deflection and jetting of a paramagnetic particle-laden fluid: theory and experiment
We describe the results of experiments and mathematical analysis of the deformation of a free surface by an aggregate of magnetic particles. The system we study is differentiated from ferrofluid systems because it contains regions rich with magnetic material as well as regions of negligible magnetic content. In our experiments, the magnetic force from a spherical permanent magnet collects magnetic particles to a liquid–air interface, and deforms the free surface to form a hump. The hump is composed of magnetic and non-magnetic regions due to the particle collection. When the magnet distance falls below a threshold value, we observe the transition of the hump to a jet. The mathematical model we develop, which consists of a numerical solution and an asymptotic approximation, captures the shape of the liquid–air interface during the deformation stage and a scaling prediction for the critical magnet distance for the hump to become a jet
New identities involving q-Euler polynomials of higher order
In this paper we give new identities involving q-Euler polynomials of higher
order.Comment: 11 page
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