1,055 research outputs found
The limit set of the handlebody set has measure zero
This note fixes a small gap in Kerckhoff's proof that the limit set of the
handlebody set has measure zero.Comment: 3 page
Measurement of the Homogeneous Contact of a Unitary Fermi gas
By selectively probing the center of a trapped gas, we measure the local, or
homogeneous, contact of a unitary Fermi gas as a function of temperature. Tan's
contact, C, is proportional to the derivative of the energy with respect to the
interaction strength, and is thus an essential thermodynamic quantity for a gas
with short-range correlations. Theoretical predictions for the temperature
dependence of C differ substantially, especially near the superfluid
transition, Tc, where C is predicted to either sharply decrease, sharply
increase, or change very little. For T/T_F>0.4, our measurements of the
homogeneous gas contact show a gradual decrease of C with increasing
temperature, as predicted by theory. We observe a sharp decrease in C at
T/T_F=0.16, which may be due to the superfluid phase transition. While a sharp
decrease in C below Tc is predicted by some many-body theories, we find that
none of the predictions fully accounts for the data.Comment: 5 pages, including a supplementary material section (10 pages).
Rewriting of the introduction and discussion section
A method for dense packing discovery
The problem of packing a system of particles as densely as possible is
foundational in the field of discrete geometry and is a powerful model in the
material and biological sciences. As packing problems retreat from the reach of
solution by analytic constructions, the importance of an efficient numerical
method for conducting \textit{de novo} (from-scratch) searches for dense
packings becomes crucial. In this paper, we use the \textit{divide and concur}
framework to develop a general search method for the solution of periodic
constraint problems, and we apply it to the discovery of dense periodic
packings. An important feature of the method is the integration of the unit
cell parameters with the other packing variables in the definition of the
configuration space. The method we present led to improvements in the
densest-known tetrahedron packing which are reported in [arXiv:0910.5226].
Here, we use the method to reproduce the densest known lattice sphere packings
and the best known lattice kissing arrangements in up to 14 and 11 dimensions
respectively (the first such numerical evidence for their optimality in some of
these dimensions). For non-spherical particles, we report a new dense packing
of regular four-dimensional simplices with density
and with a similar structure to the densest known tetrahedron packing.Comment: 15 pages, 5 figure
Probing the muon (g-2) anomaly at the LHC in final states with two muons and two taus
The longstanding muon anomaly, as well as the persistent hints of
lepton flavor universality violation in -meson decays, could be signaling
new physics beyond the Standard Model (SM). A minimal -parity-violating
supersymmetric framework with light third-generation sfermions (dubbed as
'RPV3') provides a compelling solution to these flavor anomalies, while
simultaneously addressing other pressing issues of the SM. We propose a new
RPV3 scenario for the solution of the muon anomaly, which leads to an
interesting LHC signal of final state. We analyze the
Run-2 LHC multilepton data to derive stringent constraints on the sneutrino
mass and the relevant RPV coupling in this scenario. We then propose dedicated
selection strategies to improve the bound even with the existing dataset. We
also show that the high-luminosity LHC will completely cover the remaining muon
-preferred parameter space, thus providing a robust, independent test of
the muon anomaly.Comment: 10 pages, 5 figure
Period 2: A Regulator of Multiple Tissue-Specific Circadian Functions
The zebrafish represents a powerful model for exploring how light regulates the circadian clock due to the direct light sensitivity of its peripheral clocks, a property that is retained even in organ cultures as well as zebrafish-derived cell lines. Light-inducible expression of the per2 clock gene has been predicted to play a vital function in relaying light information to the core circadian clock mechanism in many organisms, including zebrafish. To directly test the contribution of per2 to circadian clock function in zebrafish, we have generated a loss-of-function per2 gene mutation. Our results reveal a tissue-specific role for the per2 gene in maintaining rhythmic expression of circadian clock genes, as well as clock-controlled genes, and an impact on the rhythmic behavior of intact zebrafish larvae. Furthermore, we demonstrate that disruption of the per2 gene impacts on the circadian regulation of the cell cycle in vivo. Based on these results, we hypothesize that in addition to serving as a central element of the light input pathway to the circadian clock, per2 acts as circadian regulator of tissue-specific physiological functions in zebrafish
The interaction between colloids in polar mixtures above Tc
We calculate the interaction potential between two colloids immersed in an
aqueous mixture containing salt near or above the critical temperature. We find
an attractive interaction far from the coexistence curve due to the combination
of preferential solvent adsorption at the colloids' surface and preferential
ion solvation. We show that the ion-specific interaction strongly depends on
the amount of salt added as well as on the mixture composition. Our results are
in accord with recent experiments. For a highly antagonistic salt of
hydrophilic anions and hydrophobic cations, a repulsive interaction at an
intermediate inter-colloid distance is predicted even though both the
electrostatic and adsorption forces alone are attractive.Comment: 9 pages, 6 figure
Elevated red cell distribution width predicts poor outcome in young patients with community acquired pneumonia
Topological States and Adiabatic Pumping in Quasicrystals
The unrelated discoveries of quasicrystals and topological insulators have in
turn challenged prevailing paradigms in condensed-matter physics. We find a
surprising connection between quasicrystals and topological phases of matter:
(i) quasicrystals exhibit nontrivial topological properties and (ii) these
properties are attributed to dimensions higher than that of the quasicrystal.
Specifically, we show, both theoretically and experimentally, that
one-dimensional quasicrystals are assigned two-dimensional Chern numbers and,
respectively, exhibit topologically protected boundary states equivalent to the
edge states of a two-dimensional quantum Hall system.We harness the topological
nature of these states to adiabatically pump light across the quasicrystal. We
generalize our results to higher-dimensional systems and other topological
indices. Hence, quasicrystals offer a new platform for the study of topological
phases while their topology may better explain their surface properties.Comment: 10 pages, 5 figures, 4 appendice
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