18,066 research outputs found
QCD at Finite Density and Color Superconductivity
Brief review of current status of the field.Comment: Invited talk at Lattice 99, Pisa, July 1999. 5 pages, 7 fig
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Efficient Memory-Protected Integration of Add-On Software Subsystems in Small Embedded Automotive Applications
Current innovations in the automotive industry
evolve mainly in the electronics and software domain. This leads
to an increasing integration of additional software subsystems
into already existing electronic control units (ECUs) to cope with
the raised amount and complexity of present ECUs in modern
high-end vehicles. This paper discusses different approaches
which are required to integrate such add-on software subsystems
in an isolated memory domain, and considers particularly the
special needs of small embedded systemsâincluding the limited
hardware support. Special focus is brought to the efficient detection
of malicious memory accesses, as well as the benefits of
a thereupon possible and adaptable failure-handling strategy.
All investigations are based on a developed memory-protection
framework which has been tailored to the special needs of a sample
vehicle dynamics control system. Its usage allows the combination
of. integrating additional subsystems without reducing the main
applicationâs availability
Mass Terms in Effective Theories of High Density Quark Matter
We study the structure of mass terms in the effective theory for
quasi-particles in QCD at high baryon density. To next-to-leading order in the
expansion we find two types of mass terms, chirality conserving
two-fermion operators and chirality violating four-fermion operators. In the
effective chiral theory for Goldstone modes in the color-flavor-locked (CFL)
phase the former terms correspond to effective chemical potentials, while the
latter lead to Lorentz invariant mass terms. We compute the masses of Goldstone
bosons in the CFL phase, confirming earlier results by Son and Stephanov as
well as Bedaque and Sch\"afer. We show that to leading order in the coupling
constant there is no anti-particle gap contribution to the mass of
Goldstone modes, and that our results are independent of the choice of gauge.Comment: 22 pages, 4 figure
Cold dilute neutron matter on the lattice I: Lattice virial coefficients and large scattering lengths
We study cold dilute neutron matter on the lattice using an effective field
theory. We work in the unitary limit in which the scattering length is much
larger than the interparticle spacing. In this paper we focus on the equation
of state at temperatures above the Fermi temperature and compare lattice
simulations to the virial expansion on the lattice and in the continuum. We
find that in the unitary limit lattice discretization errors in the second
virial coefficient are significantly enhanced. As a consequence the equation of
state does not show the universal scaling behavior expected in the unitary
limit. We suggest that scaling can be improved by tuning the second virial
coefficient rather than the scattering length.Comment: 17 pages, 12 figure
Superdense Matter
We review recent work on the phase structure of QCD at very high baryon
density. We introduce the phenomenon of color superconductivity and discuss the
use of weak coupling methods. We study the phase structure as a function of the
number of flavors and their masses. We also introduce effective theories that
describe low energy excitations at high baryon density. Finally, we study the
possibility of kaon condensation at very large baryon density.Comment: 13 pages, talk at ICPAQGP, Jaipur, India, Nov. 26-30, 2001; to appear
in the proceeding
OPE analysis of the nucleon scattering tensor including weak interaction and finite mass effects
We perform a systematic operator product expansion of the most general form
of the nucleon scattering tensor including electro-magnetic and
weak interaction processes. Finite quark masses are taken into account and a
number of higher-twist corrections are included. In this way we derive
relations between the lowest moments of all 14 structure functions and matrix
elements of local operators. Besides reproducing well-known results, new sum
rules for parity-violating polarized structure functions and new mass
correction terms are obtained.Comment: 50 pages, additional references adde
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