186 research outputs found
Topologically Alice Strings and Monopoles
Symmetry breaking can produce ``Alice'' strings, which alter scattered
charges and carry monopole number and charge when twisted into loops. Alice
behavior arises algebraically, when strings obstruct unbroken symmetries -- a
fragile criterion. We give a topological criterion, compelling Alice behavior
or deforming it away. Our criterion, that \pi_o(H) acts nontrivially on
\pi_1(H), links topologically Alice strings to topological monopoles. We twist
topologically Alice loops to form monopoles. We show that Alice strings of
condensed matter systems (nematic liquid crystals, helium 3A, and related
non-chiral Bose condensates and amorphous chiral superconductors) are
topologically Alice, and support fundamental monopole charge when twisted into
loops. Thus they might be observed indirectly, not as strings, but as loop-like
point defects. We describe other models, showing Alice strings failing our
topological criterion; and twisted Alice loops supporting deposited, but not
fundamental, monopole number.Comment: 2 figures; this paper consolidates preprints hep-th/0304161 and
hep-th/0304162, to appear in Phys. Rev.
Lack of association of intermediate CPK-MB elevation and late mortality in patients treated with intracoronary stents
New Lump-like Structures in Scalar-field Models
In this work we investigate lump-like solutions in models described by a
single real scalar field. We start considering non-topological solutions with
the usual lump-like form, and then we study other models, where the bell-shape
profile may have varying amplitude and width, or develop a flat plateau at its
top, or even induce a lump on top of another lump. We suggest possible
applications where these exotic solutions might be used in several distinct
branches of physics.Comment: REvTex4, twocolumn, 10 pages, 9 figures; new reference added, to
appear in EPJ
Defective Erythrocyte Pyruvate Kinase with Impaired Kinetics and Reduced Optimal Activity
A unique mutant form of erythrocyte pyruvate kinase has been found associated with chronic haemolytic anaemia in a child who is apparently doubly heterozygous for the mutant isoenzyme and for pyruvate kinase deficiency of the classical quantitative type. Clinical and laboratory findings conformed closely to those typically observed in homozygous pyruvate kinase deficiency anaemia. Assayed in fresh haemolysates, the isoenzyme exhibited reduced optimal activity ( c 45% of normal) and an increased Michaelis constant for phosphoenolpyruvate (four to five times greater than normal). The kinetic anomaly was only partially corrected by activation with fructose-1,6-disphosphate. Despite some common characteristics, this isoenzyme appears distinct from others reported in the literature and lends support to the polymorphous nature of heritable baemolytic anaemias secondary to defective pyruvate kinase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73844/1/j.1365-2141.1972.tb05713.x.pd
Quantum Creation of an Open Inflationary Universe
We discuss a dramatic difference between the description of the quantum
creation of an open universe using the Hartle-Hawking wave function and the
tunneling wave function. Recently Hawking and Turok have found that the
Hartle-Hawking wave function leads to a universe with Omega = 0.01, which is
much smaller that the observed value of Omega > 0.3. Galaxies in such a
universe would be about light years away from each other, so the
universe would be practically structureless. We will argue that the
Hartle-Hawking wave function does not describe the probability of the universe
creation. If one uses the tunneling wave function for the description of
creation of the universe, then in most inflationary models the universe should
have Omega = 1, which agrees with the standard expectation that inflation makes
the universe flat. The same result can be obtained in the theory of a
self-reproducing inflationary universe, independently of the issue of initial
conditions. However, there exist two classes of models where Omega may take any
value, from Omega > 1 to Omega << 1.Comment: 23 pages, 4 figures. New materials are added. In particular, we show
that boundary terms do not help to solve the problem of unacceptably small
Omega in the new model proposed by Hawking and Turok in hep-th/9803156. A
possibility to solve the cosmological constant problem in this model using
the tunneling wave function is discusse
Proximity effect at superconducting Sn-Bi2Se3 interface
We have investigated the conductance spectra of Sn-Bi2Se3 interface junctions
down to 250 mK and in different magnetic fields. A number of conductance
anomalies were observed below the superconducting transition temperature of Sn,
including a small gap different from that of Sn, and a zero-bias conductance
peak growing up at lower temperatures. We discussed the possible origins of the
smaller gap and the zero-bias conductance peak. These phenomena support that a
proximity-effect-induced chiral superconducting phase is formed at the
interface between the superconducting Sn and the strong spin-orbit coupling
material Bi2Se3.Comment: 7 pages, 8 figure
Heavy Quarks and Heavy Quarkonia as Tests of Thermalization
We present here a brief summary of new results on heavy quarks and heavy
quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma
Thermalization" Workshop in Vienna, Austria in August 2005, directly following
the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop
(Vienna August 2005) Proceeding
Centrality Dependence of the High p_T Charged Hadron Suppression in Au+Au collisions at sqrt(s_NN) = 130 GeV
PHENIX has measured the centrality dependence of charged hadron p_T spectra
from central Au+Au collisions at sqrt(s_NN)=130 GeV. The truncated mean p_T
decreases with centrality for p_T > 2 GeV/c, indicating an apparent reduction
of the contribution from hard scattering to high p_T hadron production. For
central collisions the yield at high p_T is shown to be suppressed compared to
binary nucleon-nucleon collision scaling of p+p data. This suppression is
monotonically increasing with centrality, but most of the change occurs below
30% centrality, i.e. for collisions with less than about 140 participating
nucleons. The observed p_T and centrality dependence is consistent with the
particle production predicted by models including hard scattering and
subsequent energy loss of the scattered partons in the dense matter created in
the collisions.Comment: 7 pages text, LaTeX, 6 figures, 2 tables, 307 authors, resubmitted to
Phys. Lett. B. Revised to address referee concerns. Plain text data tables
for the points plotted in figures for this and previous PHENIX publications
are publicly available at
http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
Single Electrons from Heavy Flavor Decays in p+p Collisions at sqrt(s) = 200 GeV
The invariant differential cross section for inclusive electron production in
p+p collisions at sqrt(s) = 200 GeV has been measured by the PHENIX experiment
at the Relativistic Heavy Ion Collider over the transverse momentum range $0.4
<= p_T <= 5.0 GeV/c at midrapidity (eta <= 0.35). The contribution to the
inclusive electron spectrum from semileptonic decays of hadrons carrying heavy
flavor, i.e. charm quarks or, at high p_T, bottom quarks, is determined via
three independent methods. The resulting electron spectrum from heavy flavor
decays is compared to recent leading and next-to-leading order perturbative QCD
calculations. The total cross section of charm quark-antiquark pair production
is determined as sigma_(c c^bar) = 0.92 +/- 0.15 (stat.) +- 0.54 (sys.) mb.Comment: 329 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss in Au+Au Collisions at sqrt(s_NN)=200 GeV
The PHENIX experiment has measured mid-rapidity transverse momentum spectra
(0.4 < p_T < 5.0 GeV/c) of electrons as a function of centrality in Au+Au
collisions at sqrt(s_NN)=200 GeV. Contributions from photon conversions and
from light hadron decays, mainly Dalitz decays of pi^0 and eta mesons, were
removed. The resulting non-photonic electron spectra are primarily due to the
semi-leptonic decays of hadrons carrying heavy quarks. Nuclear modification
factors were determined by comparison to non-photonic electrons in p+p
collisions. A significant suppression of electrons at high p_T is observed in
central Au+Au collisions, indicating substantial energy loss of heavy quarks.Comment: 330 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
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