7,687 research outputs found
Quantum quench dynamics of the Coulomb Luttinger model
We study the non-equilibrium dynamics of the Luttinger model after suddenly
turning on and off the bare Coulomb interaction between the fermions. We
analyze several correlation functions such as the one particle density matrix
and vertex correlations, its finite time dynamics and the stationary state
limit. Correlations exhibit a non-linear light cone effect: the spreading of
the initial signal accelerates as a consequence of the quantum nature of the
excitations, whose peculiar dispersion of plasmonic type in 1D gives rise to a
logarithmic divergence in the group velocity at . In addition we show that
both the static and dynamic stationary state correlations can be reproduced
with a simple generalised Gibbs ensemble despite the long-range character of
the interactions which precludes the application of the Lieb-Robinson bounds.
We propose a suitable experimental setup in which these effect can be observed
based on ultracold ions loaded on linear traps.Comment: 13 pages, 7 figure
Equations of Motion for the Out-of-Equilibrium Dynamics of Isolated Quantum Systems from the Projection Operator Technique
We present a rigorous framework to obtain evolution equations for the
momentum distribution and higher order correlation functions in weakly
interacting systems based on the Projection Operator Technique. These equations
can be numerically solved in an efficient way. We compare the solution of the
equations with known results for 1D models and find an excellent agreement.Comment: 6 pages, 1 figure, added brief discussion about the validity of the
approximation
Thioxoethenylidene (CCS) as a bridging ligand
The reaction of [Mo(âĄCBr)(CO)2(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with [Fe2(ÎŒ-SLi)2(CO)6] affords, inter alia, the unsymmetrical binuclear thioxoethenylidene complex [Mo2(ÎŒ,Ï(C):η2(CâČS)-CCS)(CO)4(Tp*)2], which may be more directly obtained from [Mo(âĄCBr)(CO)2(Tp*)] and Li2S. The reaction presumably proceeds via the intermediacy of the bis(alkylidynyl)thioether complex S{CâĄMo(CO)2(Tp*)}2, which was, however, not directly observed but explored computationally and found to lie 78.6 kJ molâ1 higher in energy than the final thioxoethenylidene product. Computational interrogation of the molecules [M2(ÎŒ-C2S)(CO)2(Tp*)2] (M = Mo, W, Re, Os) reveals three plausible coordination modes for a thioxoethenylidene bridge which involve a progressive strengthening of the CâC bond and weakening of the MâC and MâS bonds, as might be expected from simple effective atomic number considerations.This work was supported by the Australian Research Council (DP130102598 and DP110101611)
The role of premotor and parietal cortex during monitoring of involuntary movement: a combined TMS and tDCS study.
Cerium-Doped Fused-Silica Fibers as Wavelength Shifters
We have evaluated the performance of a Ce-doped fused-silica fiber as
wavelength shifter coupled to a CeF crystal using electron beams at CERN.
The pulse shape and collection efficiency were measured using irradiated (100
kGy) and un-irradiated fibers. In addition, we evaluated the light yield of
various Ce-doped fibers and explored the possibility of using them in the
future, including for precision timing applications in a high-luminosity
collider environment.Comment: 11 pages, 7 figure
Proposal for SPS beam time for the baby MIND and TASD neutrino detector prototypes
The design, construction and testing of neutrino detector prototypes at CERN
are ongoing activities. This document reports on the design of solid state baby
MIND and TASD detector prototypes and outlines requirements for a test beam at
CERN to test these, tentatively planned on the H8 beamline in the North Area,
which is equipped with a large aperture magnet. The current proposal is
submitted to be considered in light of the recently approved projects related
to neutrino activities with the SPS in the North Area in the medium term
2015-2020
Emerging Non-Anomalous Baryonic Symmetries in the AdS_5/CFT_4 Correspondence
We study the breaking of baryonic symmetries in the AdS_5/CFT_4
correspondence for D3 branes at Calabi-Yau three-fold singularities. This
leads, for particular VEVs, to the emergence of non-anomalous baryonic
symmetries during the renormalization group flow. We claim that these VEVs
correspond to critical values of the B-field moduli in the dual supergravity
backgrounds. We study in detail the C^3/Z_3 orbifold, the cone over F_0 and the
C^3/Z_5 orbifold. For the first two examples, we study the dual supergravity
backgrounds that correspond to the breaking of the emerging baryonic symmetries
and identify the expected Goldstone bosons and global strings in the infra-red.
In doing so we confirm the claim that the emerging symmetries are indeed
non-anomalous baryonic symmetries.Comment: 65 pages, 15 figures;v2: minor changes, published versio
Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests
A prototype for a sampling calorimeter made out of cerium fluoride crystals
interleaved with tungsten plates, and read out by wavelength-shifting fibres,
has been exposed to beams of electrons with energies between 20 and 150 GeV,
produced by the CERN Super Proton Synchrotron accelerator complex. The
performance of the prototype is presented and compared to that of a Geant4
simulation of the apparatus. Particular emphasis is given to the response
uniformity across the channel front face, and to the prototype's energy
resolution.Comment: 6 pages, 6 figures, Submitted to NIM
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