55,077 research outputs found
Dilepton Production at Fermilab and RHIC
Some recent results from several fixed-target dimuon production experiments
at Fermilab are presented. In particular, we discuss the use of Drell-Yan data
to determine the flavor structure of the nucleon sea, as well as to deduce the
energy-loss of partons traversing nuclear medium. Future dilepton experiments
at RHIC could shed more light on the flavor asymmetry and possible
charge-symmetry-violation of the nucleon sea. Clear evidence for scaling
violation in the Drell-Yan process could also be revealed at RHIC.Comment: 5 pages, talk presented at the RIKEN-BNL Workshop on 'Hard Parton
Physics in Nucleus-Nucleus collisions, March 199
High-Energy Hadron-Induced Dilepton Production from Nucleons and Nuclei
We review the production of high-mass lepton pairs in fixed-target
experiments, including both Drell-Yan (DY) and heavy quarkonium (J/Psi and
Upsilons) production.Comment: 50 pages. To appear in Annual Review of Nuclear and Particle Science,
199
Continuous-Variable Quantum State Transfer with Partially Disembodied Transport
We propose a new protocol of implementing continuous-variable quantum state
transfer using partially disembodied transport. This protocol may improve the
fidelity at the expense of the introduction of a semi-quantum channel between
the parties, in comparison with quantum teleportation using the same strength
of entanglement. Depending on the amount of information destroyed in the
measurement, this protocol may be regarded as a teleportation protocol
(complete destruction of input state), or as a cloning protocol
(partial destruction), or as a direct transmission (no destruction). This
scheme can be straightforwardly implemented with the experimentally accessible
setup at present.Comment: 4 pages, to appear in Phys. Rev. Let
Neutron Transversity at Jefferson Lab
Nucleon transversity and single transverse spin asymmetries have been the
recent focus of large efforts by both theorists and experimentalists. On-going
and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton
or the deuteron. Presented here is a planned measurement of the neutron
transversity and single target spin asymmetries at Jefferson Lab in Hall A
using a transversely polarized He target. Also presented are the results
and plans of other neutron transverse spin experiments at Jefferson Lab.
Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is
discussed.Comment: 8 pages, 2 figures, proceedings of Como Transversity05 Worksho
Correlation between incoherent phase fluctuations and disorder in YPrBaCuO epitaxial films from Nernst effect measurements
Measurements of Nernst effect, resistivity and Hall angle on epitaxial films
of YPrBaCuO(Pr-YBCO, 00.4) are
reported over a broad range of temperature and magnetic field. While the Hall
and resistivity data suggest a broad pseudogap regime in accordance with
earlier results, these first measurements of the Nernst effect on Pr-YBCO show
a large signal above the superconducting transition temperature(T). This
effect is attributed to vortex-like excitations in the phase incoherent
condensate existing above T. A correlation between disorder and the width
of the phase fluctuation regime has been established for the YBCO family of
cuprates, which suggests a T110K for disorder-free
YBaCuO.Comment: 5 pages, 6 figure
Experimental Demonstration of Quantum State Multi-meter and One-qubit Fingerprinting in a Single Quantum Device
We experimentally demonstrate in NMR a quantum interferometric multi-meter
for extracting certain properties of unknown quantum states without resource to
quantum tomography. It can perform direct state determinations,
eigenvalue/eigenvector estimations, purity tests of a quantum system, as well
as the overlap of any two unknown quantum states. Using the same device, we
also demonstrate one-qubit quantum fingerprinting
Hardy's Paradox for High-Dimensional Systems: Beyond Hardy's Limit
Hardy's proof is considered the simplest proof of nonlocality. Here we
introduce an equally simple proof that (i) has Hardy's as a particular case,
(ii) shows that the probability of nonlocal events grows with the dimension of
the local systems, and (iii) is always equivalent to the violation of a tight
Bell inequality.Comment: REVTeX4, 5 pages, 1 figure. Typo in Eq. (17) corrected. Ref. [5]
complete
Magnitude and Sign Correlations in Heartbeat Fluctuations
We propose an approach for analyzing signals with long-range correlations by
decomposing the signal increment series into magnitude and sign series and
analyzing their scaling properties. We show that signals with identical
long-range correlations can exhibit different time organization for the
magnitude and sign. We find that the magnitude series relates to the nonlinear
properties of the original time series, while the sign series relates to the
linear properties. We apply our approach to the heartbeat interval series and
find that the magnitude series is long-range correlated, while the sign series
is anticorrelated and that both magnitude and sign series may have clinical
applications.Comment: 4 pages,late
Anomalous Meissner effect in pnictide superconductors
The Meissner effect has been studied in Ba(Fe0.926Co0.074)2As2 and
Ba0.6K0.4Fe2As2 single crystals and compared to well known, type-II
superconductors LuNi2B2C and V3Si. Whereas flux penetration is mostly
determined by the bulk pinning (and, perhaps, surface barrier) resulting in a
large negative magnetization, the flux expulsion upon cooling in a magnetic
field is very small, which could also be due to pinning and/or surface barrier
effects. However, in stark contrast with the expected behavior, the amount of
the expelled flux increases almost linearly with the applied magnetic field, at
least up to our maximum field of 5.5 T, which far exceeds the upper limit for
the surface barrier. One interpretation of the observed behavior is that there
is a field-driven suppression of magnetic pair-breaking
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