8,690 research outputs found
Exact ground state of the generalized three-dimensional Shastry-Sutherland model
We generalize the Shastry-Sutherland model to three dimensions. By
representing the model as a sum of the semidefinite positive projection
operators, we exactly prove that the model has exact dimer ground state.
Several schemes for constructing the three-dimensional Shastry-Sutherland model
are proposed.Comment: Latex, 3 pages, 5 eps figure
Non-zero U_{e3} and TeV-Leptogenesis through A_4 symmetry breaking
We consider an effective theory with an symmetry and investigate the possibility of a linking
TeV-leptogenesis with a reactor angle through spontaneous
symmetry breaking which is at a scale higher than electroweak scale under the
framework of radiative seesaw. It has been shown that tri-bimaximal(TBM) can be
obtained by forging vacuum expectation value (VEV) alignment of the .
Especially, one triplet scalar field with cut-off scale is
added in neutrino Yukawa sector, which is responsible for the deviation of the
exact TBM, to explain leptogenesis as well as a non-zero . Above the
scale of the leptonic Yukawa sectors will lead to the exact TBM. We
analyze possible spectrums of light neutrinos and their flavor mixing angles
corresponding to heavy Majorana neutrino mass ordering, and show that
non-resonance leptogenesis at TeV-scale constrained by low energy data is
achievable, both analytically as well as numerically. We show that only normal
hierarchical spectrum of light neutrino would be strongly favored by the
current Wilkinson Microwave Anisotropy Probe (WMAP) data, and also show that a
relatively large corresponds to the value of baryon asymmetry
.Comment: 32 pages, 21 figures, 3 tables. Final version to appear in Phys. Rev.
Quantum Information Approach to Bose-Einstein Condensate in a Tilted Double-Well System
We study the ground state properties of bosons in a tilted double-well
system. We use fidelity susceptibility to identify the possible ground state
transitions under different tilt values. For a very small tilt (for example
), two transitions are found. For a moderate tilt (for example
), only one transition is found. For a large tilt (for example
), no transition is found. We explain this by analyzing the spectrum
of the ground state. The quantum discord and total correlation of the ground
state under different tilts are also calculated to indicate those transitions.
In the transition region, both quantities have peaks decaying exponentially
with particle number . This means for a finite-size system the transition
region cannot be explained by the mean-field theory, but in the large- limit
it can be.Comment: 5 pages, 5 figures, slightly different from the published versio
Construction of a polarization insensitive lens from a quasi-isotropic metamaterial slab
We propose to employ the quasiisotropic metamaterial (QIMM) slab to construct
a polarization insensitive lens, in which both E- and H-polarized waves exhibit
the same refocusing effect. For shallow incident angles, the QIMM slab will
provide some degree of refocusing in the same manner as an isotropic negative
index material. The refocusing effect allows us to introduce the ideas of
paraxial beam focusing and phase compensation by the QIMM slab. On the basis of
angular spectrum representation, a formalism describing paraxial beams
propagating through a QIMM slab is presented. Because of the negative phase
velocity in the QIMM slab, the inverse Gouy phase shift and the negative
Rayleigh length of paraxial Gaussian beam are proposed. We find that the phase
difference caused by the Gouy phase shift in vacuum can be compensated by that
caused by the inverse Gouy phase shift in the QIMM slab. If certain matching
conditions are satisfied, the intensity and phase distributions at object plane
can be completely reconstructed at image plane. Our simulation results show
that the superlensing effect with subwavelength image resolution could be
achieved in the form of a QIMM slab.Comment: 25 pages, 8 figure
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Extracellular RNA in a single droplet of human serum reflects physiologic and disease states.
Extracellular RNAs (exRNAs) are present in human serum. It remains unclear to what extent these circulating exRNAs may reflect human physiologic and disease states. Here, we developed SILVER-seq (Small Input Liquid Volume Extracellular RNA Sequencing) to efficiently sequence both integral and fragmented exRNAs from a small droplet (5 μL to 7 μL) of liquid biopsy. We calibrated SILVER-seq in reference to other RNA sequencing methods based on milliliters of input serum and quantified droplet-to-droplet and donor-to-donor variations. We carried out SILVER-seq on more than 150 serum droplets from male and female donors ranging from 18 y to 48 y of age. SILVER-seq detected exRNAs from more than a quarter of the human genes, including small RNAs and fragments of mRNAs and long noncoding RNAs (lncRNAs). The detected exRNAs included those derived from genes with tissue (e.g., brain)-specific expression. The exRNA expression levels separated the male and female samples and were correlated with chronological age. Noncancer and breast cancer donors exhibited pronounced differences, whereas donors with or without cancer recurrence exhibited moderate differences in exRNA expression patterns. Even without using differentially expressed exRNAs as features, nearly all cancer and noncancer samples and a large portion of the recurrence and nonrecurrence samples could be correctly classified by exRNA expression values. These data suggest the potential of using exRNAs in a single droplet of serum for liquid biopsy-based diagnostics
Superluminal group velocity in an anisotropic metamaterial
Based on boundary condition and dispersion relation, the superluminal group
velocity in an anisotropic metamaterial (AMM) is investigated. The superluminal
propagation is induced by the hyperbolic dispersion relation associated with
the AMM. It is shown that a modulated Gaussian beam exhibits a superluminal
group velocity which depends on the choice of incident angles and optical axis
angles. The superluminal propagation does not violate the theory of special
relativity because the group velocity is the velocity of the peak of the
localized wave packet which does not carry information. It is proposed that a
triglycine sulfate (TGS) crystal can be designed and the superluminal group
velocity can be measured experimentally.Comment: 9 pages, 3 figure
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