409 research outputs found
Quantum simulation of Fermi-Hubbard models in semiconductor quantum dot arrays
We propose a device for studying the Fermi-Hubbard model with long-range
Coulomb interactions using an array of quantum dots defined in a semiconductor
two-dimensional electron gas system. Bands with energies above the lowest
energy band are used to form the Hubbard model, which allows for an
experimentally simpler realization of the device. We find that depending on
average electron density, the system is well described by a one- or two-band
Hubbard model. Our device design enables the control of the ratio of the
Coulomb interaction to the kinetic energy of the electrons independently to the
filling of the quantum dots, such that a large portion of the Hubbard phase
diagram may be probed. Estimates of the Hubbard parameters suggest that a
metal-Mott insulator quantum phase transition and a d-wave superconducting
phase should be observable using current fabrication technologies.Comment: 12 pages, 3 figures, 1 table
Hypothetical membrane mechanisms in essential tremor
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Non--decoupling, triviality and the parameter
The dependence of the parameter on the mass of the Higgs scalar and
the top quark is computed non--perturbatively using the expansion in
the standard model. We find an explicit expression for the parameter
that requires the presence of a physical cutoff. This should come as no
surprise since the theory is presumably trivial. By taking this cutoff into
account, we find that the parameter can take values only within a
limited range and has finite ambiguities that are suppressed by inverse powers
of the cutoff scale, the so called ``scaling--violations". We find that large
deviations from the perturbative results are possible, but only when the cutoff
effects are also large.Comment: 16pp, Figures NOT included, harvmac, minor modifications incl.
wording, refs., UCLA/92/TEP/23,OHSTPY-HEP-T-92-00
Enhanced Urinary Bladder, Liver and Colon Carcinogenesis in Zucker Diabetic Fatty Rats in a Multiorgan Carcinogenesis Bioassay: Evidence for Mechanisms Involving Activation of PI3K Signaling and Impairment of p53 on Urinary Bladder Carcinogenesis
In the present study, modifying effects of diabetes on carcinogenesis induced in type 2
diabetes mellitus model Zucker diabetic fatty (ZDF) rats were investigated using a
multiorgan carcinogenesis bioassay. Our re sults demonstrated enhancement of urinary
bladder, colon and liver carcinogenesis in ZDF rats treated with five types of carcinogens
(DMBDD). Elevated insulin and leptin and decreased adiponectin levels in the serum may be
responsible for the high susceptibility of type 2 diabetes mellitus model rats to
carcinogenesis in these organs. Possible mechanisms of increased susceptibility of
diabetic rats to bladder carcinogenesis could be activation of the PI3K pathway and
suppression of p53 in the urothelium in consequence of the above serum protein
alterations
Gauss-Bonnet brane-world cosmology without -symmetry
We consider a single 3-brane situated between two bulk spacetimes that posses
the same cosmological constant, but whose metrics do not posses a
-symmetry. On each side of the brane, the bulk is a solution to
Gauss-Bonnet gravity. This asymmetry modifies junction conditions, and so new
terms arise in the Friedmann equation. If these terms become dominant, these
behave cosmological constant at early times for some case, and might remove the
initial singularity for other case. However, we show that these new terms can
not become dominant ones under usual conditions when our brane is outside an
event horizon. We also show that any brane-world scenarios of this type revert
to a -symmetric form at late times, and hence rule out certain proposed
scenarios.Comment: 8 pages, 3 figures; Minor typos corrected. References added. V3:
Numerical errors are corrected. Fig.1 and Fig.3 are replaced. V4: published
versio
Boson--fermion bound states in two dimensional QCD
We derive the boson--fermion bound state equation in a two dimensional gauge
theory in the large--\nc limit. We analyze the properties of this equation
and in particular, find that the mass trajectory is linear with respect to the
bound state level for the higher mass states.Comment: 5pp, 2 figs (as a separate file), TIT/HEP-23
1+1 dimensional QCD with fundamental bosons and fermions
We analyze the properties of mesons in 1+1 dimensional QCD with bosonic and
fermionic ``quarks'' in the large \nc limit. We study the spectrum in detail
and show that it is impossible to obtain massless mesons including boson
constituents in this model. We quantitatively show how the QCD mass inequality
is realized in two dimensional QCD. We find that the mass inequality is close
to being an equality even when the quarks are light. Methods for obtaining the
properties of ``mesons'' formed from boson and/or fermion constituents are
formulated in an explicit manner convenient for further study. We also analyze
how the physical properties of the mesons such as confinement and asymptotic
freedom are realized.Comment: 20 pages, harvmac, 5 figure
Phase equilibria and interfacial tension of fluids confined in narrow pores
Correlation between phase behaviors of a Lennard-Jones fluid in and outside a pore is examined over wide thermodynamic conditions by grand canonical Monte Carlo simulations. A pressure tensor component of the confined fluid, a variable controllable in simulation but usually uncontrollable in experiment, is related with the pressure of a bulk homogeneous system in equilibrium with the confined system. Effects of the pore dimensionality, size, and attractive potential on the correlations between thermodynamic properties of the confined and bulk systems are clarified. A fluid-wall interfacial tension defined as an excess grand potential is evaluated as a function of the pore size. It is found that the tension decreases linearly with the inverse of the pore diameter or width
Are B cells altered in the decidua of women with preterm or term labor?
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149277/1/aji13102_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149277/2/aji13102.pd
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