25,859 research outputs found
Baryon-strangeness correlations: a diagnostic of strongly interacting matter
The correlation between baryon number and strangeness elucidates the nature
of strongly interacting matter, such as that formed transiently in high-energy
nuclear collisions. This diagnostic can be extracted theoretically from lattice
QCD calculations and experimentally from event-by-event fluctuations. The
analysis of present lattice results above the critical temperature severely
limits the presence of q-qbar bound states, thus supporting a picture of
independent (quasi)quarks.Comment: 4 pages, 2 eps figures, Revised: several sign typos have been fixed
(the PRL version is correct
Signatures for Black Hole production from hadronic observables at the Large Hadron Collider
The concept of Large Extra Dimensions (LED) provides a way of solving the
Hierarchy Problem which concerns the weakness of gravity compared with the
strong and electro-weak forces. A consequence of LED is that miniature Black
Holes (mini-BHs) may be produced at the Large Hadron Collider in p+p
collisions. The present work uses the CHARYBDIS mini-BH generator code to
simulate the hadronic signal which might be expected in a mid-rapidity particle
tracking detector from the decay of these exotic objects if indeed they are
produced. An estimate is also given for Pb+Pb collisions.Comment: 11 pages, 9 figures, ISHIP 2006 conference proceedin
A diode device combining lateral field-effect transport and vertical tunneling in a multi-quantum-well heterostructure
The authors discuss an electronic device with asymmetric contacts to a InGaAs-InP multilayer heterostructure. Current enters via an alloyed ohmic contact into the quantum wells (QWs) and flows laterally along capacitively coupled channels. It leaves via tunneling between the layers and through a forward-biased surface Schottky contact. A step-like I-V dependence is observed and interpreted by a model calculation
Baryon number and strangeness: signals of a deconfined antecedent
The correlation between baryon number and strangeness is used to discern the
nature of the deconfined matter produced at vanishing chemical potential in
high-energy nuclear collisions at the BNL RHIC. Comparisons of results of
various phenomenological models with correlations extracted from lattice QCD
calculations suggest that a quasi-particle picture applies. At finite baryon
densities, such as those encountered at the CERN SPS, it is demonstrated that
the presence of a first-order phase transition and the accompanying development
of spinodal decomposition would significantly enhance the number of strangeness
carriers and the associated fluctuations.Comment: 10 pages, 4 figures, latex, to appear in the proceedings of the
Workshop on Correlations and Fluctuations in Relativistic Nuclear collisions,
(MIT, April 21-23,2005
Crossing conditions in coupled cluster theory
We derive the crossing conditions at conical intersections between electronic
states in coupled cluster theory, and show that if the coupled cluster Jacobian
matrix is nondefective, two (three) independent conditions are correctly placed
on the nuclear degrees of freedom for an inherently real (complex) Hamiltonian.
Calculations using coupled cluster theory on an
conical intersection in hypofluorous acid illustrate the nonphysical artifacts
associated with defects at accidental same-symmetry intersections. In
particular, the observed intersection seam is folded about a space of the
correct dimensionality, indicating that minor modifications to the theory are
required for it to provide a correct description of conical intersections in
general. We find that an accidental symmetry allowed
intersection in hydrogen sulfide is properly described, showing no artifacts as
well as linearity of the energy gap to first order in the branching plane.Comment: 9 pages and 4 figure
Development of techniques to improve bladder materials and test methods Final report, May 18, 1966 - May 17, 1968
Process parameters for fabricating flexible Teflon films, crystallinity determinations, and techniques for electroplating Teflon films with lea
Towards Functional Flows for Hierarchical Models
The recursion relations of hierarchical models are studied and contrasted
with functional renormalisation group equations in corresponding
approximations. The formalisms are compared quantitatively for the Ising
universality class, where the spectrum of universal eigenvalues at criticality
is studied. A significant correlation amongst scaling exponents is pointed out
and analysed in view of an underlying optimisation. Functional flows are
provided which match with high accuracy all known scaling exponents from
Dyson's hierarchical model for discrete block-spin transformations.
Implications of the results are discussed.Comment: 17 pages, 4 figures; wording sharpened, typos removed, reference
added; to appear with PR
Polymers for spacecraft hardware Monthly technical progress report, 10 Feb. 1967 - 1 Mar. 1967
Test program for polymeric products with spacecraft application
Short-pulse photoassociation in rubidium below the D line
Photoassociation of two ultracold rubidium atoms and the subsequent formation
of stable molecules in the singlet ground and lowest triplet states is
investigated theoretically. The method employs laser pulses inducing
transitions via excited states correlated to the asymptote.
Weakly bound molecules in the singlet ground or lowest triplet state can be
created by a single pulse while the formation of more deeply bound molecules
requires a two-color pump-dump scenario. More deeply bound molecules in the
singlet ground or lowest triplet state can be produced only if efficient
mechanisms for both pump and dump steps exist. While long-range
-potentials allow for efficient photoassociation, stabilization is
facilitated by the resonant spin-orbit coupling of the states.
Molecules in the singlet ground state bound by a few wavenumbers can thus be
formed. This provides a promising first step toward ground state molecules
which are ultracold in both translational and vibrational degrees of freedom
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