6,928 research outputs found
Field-induced confinement in (TMTSF)2ClO4 under accurately aligned magnetic fields
We present transport measurements along the least conducting c direction of
the organic superconductor (TMTSF)2ClO4, performed under an accurately aligned
magnetic field in the low temperature regime. The experimental results reveal a
two-dimensional confinement of the carriers in the (a,b) planes which is
governed by the magnetic field component along the b' direction. This 2-D
confinement is accompanied by a metal-insulator transition for the c axis
resistivity. These data are supported by a quantum mechanical calculation of
the transverse transport taking into account in self consistent treatment the
effect of the field on the interplane Green function and on the intraplane
scattering time
Multiple Stellar Populations in the Globular Cluster omega Centauri as Tracers of a Merger Event
The discovery of the Sagittarius dwarf galaxy, which is being tidally
disrupted by and merging with the Milky Way, supports the view that the halo of
the Galaxy has been built up at least partially by the accretion of similar
dwarf systems. The Sagittarius dwarf contains several distinct populations of
stars, and includes M54 as its nucleus, which is the second most massive
globular cluster associated with the Milky Way. The most massive globular
cluster is omega Centauri, and here we report that omega Centauri also has
several distinct stellar populations, as traced by red-giant-branch stars. The
most metal-rich red-giant-branch stars are about 2 Gyr younger than the
dominant metal-poor component, indicating that omega Centauri was enriched over
this timescale. The presence of more than one epoch of star formation in a
globular cluster is quite surprising, and suggests that omega Centauri was once
part of a more massive system that merged with the Milky Way, as the
Sagittarius dwarf galaxy is in the process of doing now. Mergers probably were
much more frequent in the early history of the Galaxy and omega Centauri
appears to be a relict of this era.Comment: 7 pages, 3 figures, Latex+nature.sty (included), To appear in
November 4th issue of Natur
Simple scheme for expanding a polarization-entangled W state by adding one photon
We propose a simple scheme for expanding a polarization-entangled W state. By
mixing a single photon and one of the photons in an n-photon W state at a
polarization-dependent beam splitter (PDBS), we can obtain an (n+1)-photon W
state after post-selection. Our scheme also opens the door for generating
n-photon W states using single photons and linear optics.Comment: 3 pages, 2 figure
Constraint on teleportation over multipartite pure states
We first define a quantity exhibiting the usefulness of bipartite quantum
states for teleportation, called the quantum teleportation capability, and then
investigate its restricted shareability in multi-party quantum systems. In this
work, we verify that the quantum teleportation capability has a monogamous
property in its shareability for arbitrary three-qutrit pure states by
employing the monogamy inequality in terms of the negativity.Comment: 4 pages, 1 figur
Limits on Interactions between Weakly Interacting Massive Particles and Nucleons Obtained with NaI(Tl) crystal Detectors
Limits on the cross section for weakly interacting massive particles (WIMPs)
scattering off nucleons in the NaI(Tl) detectors at the Yangyang Underground
Laboratory are obtained with a 2967.4 kg*day data exposure. Nuclei recoiling
are identified by the pulse shape of scintillating photon signals. Data are
consistent with no nuclear recoil hypothesis, and 90% confidence level upper
limits are set. These limits partially exclude the DAMA/LIBRA region of
WIMP-sodium interaction with the same NaI(Tl) target detector. This 90%
confidence level upper limit on WIMP-nucleon spin-independent cross section is
3.26*10^-4 pb for a WIMP mass at 10 GeV/c^2
Correction to: Circulating exosomes from patients with systemic lupus erythematosus induce an proinflammatory immune response
An amendment to this paper has been published and can be accessed via the original article
Quantum teleportation via a W state
We investigate two schemes of the quantum teleportation with a state,
which belongs to a different class from a Greenberger-Horne-Zeilinger class. In
the first scheme, the state is shared by three parties one of whom, called
a sender, performs a Bell measurement. It is shown that quantum information of
an unknown state is split between two parties and recovered with a certain
probability. In the second scheme, a sender takes two particles of the
state and performs positive operator valued measurements in two ways. For two
schemes, we calculate the success probability and the average fidelity. We show
that the average fidelity of the second scheme cannot exceed that of the first
one.Comment: 7 pages, 1 figur
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