50,545 research outputs found
Spin-triplet pairing in large nuclei
The nuclear pairing condensate is expected to change character from
spin-singlet to spin-triplet when the nucleus is very large and the neutron and
proton numbers are equal. We investigate the transition between these two
phases within the framework of the Hartree-Fock-Bogoliubov equations, using a
zero-range interaction to generate the pairing. We confirm that extremely large
nucleus would indeed favor triplet pairing condensates, with the Hamiltonian
parameters taken from known systematics. The favored phase is found to depend
on the specific orbitals at the Fermi energy. The smallest nuclei with a
well-developed spin-triplet condensate are in the mass region A ~ 130-140.Comment: 8 pages, 2 figures, 2 table
Intruder level and deformation in the SD-pair shell model
The influence of the intruder level on nuclear deformation is studied within
the framework of the nucleon-pair shell model truncated to an SD-pair subspace.
The results suggest that the intruder level has a tendency to soften the
deformation and plays an important role in determining the onset of rotational
behavior.Comment: 2 input TeX files, 2 figures, submitted to Phys. Lett.
Disordered Kondo Nanoclusters: Effect of Energy Spacing
Exact diagonalization results for Kondo nanoclusters alloyed with mixed
valence impurities show that tuning the {\it energy spacing}, , drives
the system from the Kondo to the RKKY regime. The interplay of and
disorder gives rise to a versus concentration T=0 phase diagram very
rich in structure, where regions with prevailing Kondo or RKKY correlations
alternate with domains of ferromagnetic order. The local Kondo temperatures,
, and RKKY interactions depend strongly on the local environment and are
overall {\it enhanced} by disorder, in contrast to the hypothesis of ``Kondo
disorder'' single-impurity models.Comment: 4pages 4 figuresDisordered Kondo Nanoclusters: Effect of Energy
Spacin
Improved lattice QCD with quarks: the 2 dimensional case
QCD in two dimensions is investigated using the improved fermionic lattice
Hamiltonian proposed by Luo, Chen, Xu, and Jiang. We show that the improved
theory leads to a significant reduction of the finite lattice spacing errors.
The quark condensate and the mass of lightest quark and anti-quark bound state
in the strong coupling phase (different from t'Hooft phase) are computed. We
find agreement between our results and the analytical ones in the continuum.Comment: LaTeX file (including text + 10 figures
Comment on "Novel Convective Instabilities in a Magnetic Fluid"
Comment on the paper "Novel Convective Instabilities in a Magnetic Fluid" by
W. Luo, T. Du, and J. Huang, Phys. Rev. Lett., v.82, p.4134 (1999).Comment: 1 page, 1 figure, To appear in Phys. Rev. Lett. (2001
Six-dimensional weak-strong simulations of head-on beam-beam compensation in RHIC
To compensate the large beam-beam tune spread and beam-beam resonance driving
terms in the polarized proton operation in the Relativistic Heavy Ion Collider
(RHIC), we will introduce a low-energy DC electron beam into each ring to
collide head-on with the opposing proton beam. The device to provide the
electron beam is called an electron lens. In this article, using a 6-D
weak-strong-beam-beam interaction simulation model, we investigate the effects
of head-on beam-beam compensation with electron lenses on the proton beam
dynamics in the RHIC 250 GeV polarized proton operation. This article is
abridged from the published article [1].Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
Ultraviolet/X-ray variability and the extended X-ray emission of the radio-loud broad absorption line quasar PG 1004+130
We present the results of recent Chandra, XMM-Newton, and Hubble Space
Telescope observations of the radio-loud (RL), broad absorption line (BAL)
quasar PG 1004+130. We compare our new observations to archival X-ray and UV
data, creating the most comprehensive, high signal-to-noise, multi-epoch,
spectral monitoring campaign of a RL BAL quasar to date. We probe for
variability of the X-ray absorption, the UV BAL, and the X-ray jet, on
month-year timescales. The X-ray absorber has a low column density of
cm when it is assumed to be fully
covering the X-ray emitting region, and its properties do not vary
significantly between the 4 observations. This suggests the observed absorption
is not related to the typical "shielding gas" commonly invoked in BAL quasar
models, but is likely due to material further from the central black hole. In
contrast, the CIV BAL shows strong variability. The equivalent width (EW) in
2014 is EW=11.240.56 \AA, showing a fractional increase of =1.160.11 from the 2003 observation, 3183 days earlier
in the rest-frame. This places PG 1004+130 among the most highly variable BAL
quasars. By combining Chandra observations we create an exposure 2.5 times
deeper than studied previously, with which to investigate the nature of the
X-ray jet and extended diffuse X-ray emission. An X-ray knot, likely with a
synchrotron origin, is detected in the radio jet ~8 arcsec (30 kpc) from the
central X-ray source with a spatial extent of ~4 arcsec (15 kpc). No similar
X-ray counterpart to the counterjet is detected. Asymmetric, non-thermal
diffuse X-ray emission, likely due to inverse Compton scattering of Cosmic
Microwave Background photons, is also detected.Comment: 15 pages, 7 figures, 3 tables. Accepted for publication in Ap
Metric adjusted skew information: Convexity and restricted forms of superadditivity
We give a truly elementary proof of the convexity of metric adjusted skew
information following an idea of Effros. We extend earlier results of weak
forms of superadditivity to general metric adjusted skew informations.
Recently, Luo and Zhang introduced the notion of semi-quantum states on a
bipartite system and proved superadditivity of the Wigner-Yanase-Dyson skew
informations for such states. We extend this result to general metric adjusted
skew informations. We finally show that a recently introduced extension to
parameter values of the WYD-information is a special case of
(unbounded) metric adjusted skew information.Comment: An error in the literature is pointed ou
Inequalities for quantum skew information
We study quantum information inequalities and show that the basic inequality
between the quantum variance and the metric adjusted skew information generates
all the multi-operator matrix inequalities or Robertson type determinant
inequalities studied by a number of authors. We introduce an order relation on
the set of functions representing quantum Fisher information that renders the
set into a lattice with an involution. This order structure generates new
inequalities for the metric adjusted skew informations. In particular, the
Wigner-Yanase skew information is the maximal skew information with respect to
this order structure in the set of Wigner-Yanase-Dyson skew informations.
Key words and phrases: Quantum covariance, metric adjusted skew information,
Robertson-type uncertainty principle, operator monotone function,
Wigner-Yanase-Dyson skew information
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