768 research outputs found
Crystal Structure and Physical Properties of U3T3Sn4 (T = Ni, Cu) Single-Crystals
Heat capacity experiments, crystal structure determination and transmission
electron microscopy have been carried out on U3Cu3Sn4 single-crystals. U3Cu3Sn4
was confirmed to be a heavy-fermion antiferromagnet (TN=13(1) K) with a low
temperature electronic heat capacity coefficient gamma=390 mJ/molUK2. Low
temperature heat capacity experiments on a U3Ni3Sn4 single-crystal indicate
that below 0.4 K there is a crossover between the previously observed non-Fermi
liquid behavior and a Fermi liquid state.Comment: 12 pages (incl. 2 tables & 4 figures), to appear in Physica
Electromagnetic Response of Layered Superconductors with Broken Lattice Inversion Symmetry
We investigate the macroscopic effects of charge density waves (CDW) and
superconductivity in layered superconducting systems with broken lattice
inversion symmetry (allowing for piezoelectricity) such as two dimensional (2D)
transition metal dichalcogenides (TMD). We work with the low temperature time
dependent Ginzburg-Landau theory and study the coupling of lattice distortions
and low energy CDW collective modes to the superconducting order parameter in
the presence of electromagnetic fields. We show that superconductivity and
piezoelectricity can coexist in these singular metals. Furthermore, our study
indicates the nature of the quantum phase transition between a commensurate CDW
phase and the stripe phase that has been observed as a function of applied
pressure.Comment: 9 pages, 1 figure. Final version. Accepted in Phys.Rev.
Transport Properties through Double Barrier Structure in Graphene
The mode-dependent transmission of relativistic ballistic massless Dirac
fermion through a graphene based double barrier structure is being investigated
for various barrier parameters. We compare our results with already published
work and point out the relevance of these findings to a systematic study of the
transport properties in double barrier structures. An interesting situation
arises when we set the potential in the leads to zero, then our 2D problem
reduces effectively to a 1D massive Dirac equation with an effective mass
proportional to the quantized wave number along the transverse direction.
Furthermore we have shown that the minimal conductivity and maximal Fano factor
remain insensitive to the ratio between the two potentials V_2/V_1=\alpha.Comment: 18 pages, 12 figures, clarifications and reference added, misprints
corrected. Version to appear in JLT
The local adsorption geometry of benzenethiolate on Cu(1 0 0)
The local adsorption geometry of benzenethiolate in the ordered c(2 × 6) phase on Cu(1 0 0) has been investigated by a combination of S K-edge near-edge X-ray absorption fine structure (NEXAFS), normal incidence X-ray standing waves (NIXSW) and S 1s scanned-energy mode photoelectron diffraction (PhD). NEXAFS and PhD show that the molecular plane is tilted from the surface normal by 20 ± 15°, while NIXSW clearly identifies the S head-group as occupying the four-fold coordinated hollow sites. PhD shows the S atoms lies 1.34 ± 0.04 Å above the outermost Cu atomic layer, leading to a Cu–S bondlength of 2.25 ± 0.02 Å. The combination of the PhD and NIXSW results shows the Cu surface layer has an outward relaxation of 0.15 ± 0.06 Å. Possible origins for this large adsorbate-induced relaxation are discussed
Corrections to the statistical entropy of five dimensional black holes
We compute the statistical entropy of the three charge (D1-D5-p) five
dimensional black hole to sub-leading order in a large charge expansion. We
find an agreement with the macroscopic calculation of the Wald entropy in R^2
corrected supergravity theory. The two calculations have a overlapping regime
of validity which is not the Cardy regime. We use this result to clarify the
4d-5d lift for black holes on Taub-NUT space. In particular, we compute
sub-leading corrections to the formula S^{4d} = S^{5d}. In the microscopic
analysis, this correction arises from excitations bound to the Taub-NUT space.
In the macroscopic picture, the difference is accounted by a mechanism present
in a higher derivative theory wherein the geometry of the Taub-NUT space
absorbes some of the electric charge.Comment: 25 pages. Few changes and improvements. To be published in JHE
Adiabatic evolution of a coupled-qubit Hamiltonian
We present a general method for studying coupled qubits driven by
adiabatically changing external parameters. Extended calculations are provided
for a two-bit Hamiltonian whose eigenstates can be used as logical states for a
quantum CNOT gate. From a numerical analysis of the stationary Schroedinger
equation we find a set of parameters suitable for representing CNOT, while from
a time-dependent study the conditions for adiabatic evolution are determined.
Specializing to a concrete physical system involving SQUIDs, we determine
reasonable parameters for experimental purposes. The dissipation for SQUIDs is
discussed by fitting experimental data. The low dissipation obtained supports
the idea that adiabatic operations could be performed on a time scale shorter
than the decoherence time.Comment: 10 pages, 4 figures, to be pub.in Phys Rev
Activation of pruritogenic TGR5, MRGPRA3, and MRGPRC11 on colon-innervating afferents induces visceral hypersensitivity
Itch induces scratching that removes irritants from the skin, whereas pain initiates withdrawal or avoidance of tissue damage. While pain arises from both the skin and viscera, we investigated whether pruritogenic irritant mechanisms also function within visceral pathways. We show that subsets of colon-innervating sensory neurons in mice express, either individually or in combination, the pruritogenic receptors Tgr5 and the Mas-gene-related GPCRs Mrgpra3 and Mrgprc11. Agonists of these receptors activated subsets of colonic sensory neurons and evoked colonic afferent mechanical hypersensitivity via a TRPA1-dependent mechanism. In vivo intracolonic administration of individual TGR5, MRGPRA3, or MRGPRC11 agonists induced pronounced visceral hypersensitivity to colorectal distension. Coadministration of these agonists as an "itch cocktail" augmented hypersensitivity to colorectal distension and changed mouse behavior. These irritant mechanisms were maintained and enhanced in a model of chronic visceral hypersensitivity relevant to irritable bowel syndrome. Neurons from human dorsal root ganglia also expressed TGR5, as well as the human ortholog MRGPRX1, and showed increased responsiveness to pruritogenic agonists in pathological states. These data support the existence of an irritant-sensing system in the colon that is a visceral representation of the itch pathways found in skin, thereby contributing to sensory disturbances accompanying common intestinal disorders. - 2019 American Society for Clinical Investigation. All rights reserved.Work was supported by a National Health and Medical Research Council of Australia (NHMRC) Project Grant (1083480 to SMB and DPP), an NHMRC R.D. Wright Biomedical Research Fellow (APP1126378 to SMB), and an Australian Research Council (ARC) Discovery Early Career Research Award (DE130100223 to AMH). NWB was supported by grants from the NIH (NS102722; DE026806; DK118971) and the US Department of Defence (W81XWH1810431).Scopu
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