1,248 research outputs found
HABEAS CORPUS-FEDERAL COURTS-EXHAUSTION OF STATE REMEDIES
Petitioner\u27s writ of habeas corpus, alleging denial of due process of law in violation of the Fourteenth Amendment, was quashed on the merits by an inferior Florida court whose action was affirmed without opinion by the Florida Supreme Court. It was impossible to ascertain whether the affirmance was on the merits or on the ground that, under Florida law, habeas corpus was not the proper procedure to raise the due process issue. A later decision by the Florida Supreme Court clearly established that the prior case had been decided on the merits of the constitutional question, and that habeas corpus was available in Florida to raise the due process issue. Petitioner did not seek review of the Florida court\u27s decision by certiorari to the United States Supreme Court, but later instituted habeas corpus proceedings in a federal district court which ordered his release. On certiorari to the United States Supreme Court, held, the district court had properly exercised its discretion to issue the writ. Four justices dissented on the ground that, because petitioner had failed to exhaust his state remedies, the constitutional question was not properly before the court. Wade v. Mayo, 334 U.S. 672, 68 S.Ct. 1270 (1948)
Improved lattice operators for non-relativistic fermions
In this work I apply a recently proposed improvement procedure, originally
conceived to reduce finite lattice spacing effects in transfer matrices for
dilute Fermi systems, to tuning operators for the calculation of observables. I
construct, in particular, highly improved representations for the energy and
the contact, as a first step in an improvement program for finite-temperature
calculations. I illustrate the effects of improvement on those quantities with
a ground-state lattice calculation at unitarity.Comment: 11 pages, 7 figures; replaced with published versio
Recursive Construction of Generator for Lagrangian Gauge Symmetries
We obtain, for a subclass of structure functions characterizing a first class
Hamiltonian system, recursive relations from which the general form of the
local symmetry transformations can be constructed in terms of the independent
gauge parameters. We apply this to a non-trivial Hamiltonian system involving
two primary constraints, as well as two secondary constraints of the Nambu-Goto
type.Comment: 10 pages, Late
Thermal Quantum Fields in Static Electromagnetic Backgrounds
We present and discuss, at a general level, new mathematical results on the
spatial nonuniformity of thermal quantum fields coupled minimally to static
background electromagnetic potentials. Two distinct examples are worked through
in some detail: uniform (parallel and perpendicular) background electric and
magnetic fields coupled to a thermal quantum scalar field.Comment: 22 page
Hamiltonian Embedding of SU(2) Higgs Model in the Unitary Gauge
Following systematically the generalized Hamiltonian approach of Batalin,
Fradkin and Tyutin (BFT), we embed the second-class non-abelian SU(2) Higgs
model in the unitary gauge into a gauge invariant theory. The strongly
involutive Hamiltonian and constraints are obtained as an infinite power series
in the auxiliary fields. Furthermore, comparing these results with those
obtained from the gauged second class Lagrangian, we arrive at a simple
interpretation for the first class Hamiltonian, constraints and observables.Comment: 13 pages, Latex, no figure
Resonance ionization spectroscopy of thorium isotopes - towards a laser spectroscopic identification of the low-lying 7.6 eV isomer of Th-229
In-source resonance ionization spectroscopy was used to identify an efficient
and selective three step excitation/ionization scheme of thorium, suitable for
titanium:sapphire (Ti:sa) lasers. The measurements were carried out in
preparation of laser spectroscopic investigations for an identification of the
low-lying Th-229m isomer predicted at 7.6 +- 0.5 eV above the nuclear ground
state. Using a sample of Th-232, a multitude of optical transitions leading to
over 20 previously unknown intermediate states of even parity as well as
numerous high-lying odd parity auto-ionizing states were identified. Level
energies were determined with an accuracy of 0.06 cm-1 for intermediate and
0.15 cm-1 for auto-ionizing states. Using different excitation pathways an
assignment of total angular momenta for several energy levels was possible. One
particularly efficient ionization scheme of thorium, exhibiting saturation in
all three optical transitions, was studied in detail. For all three levels in
this scheme, the isotope shifts of the isotopes Th-228, Th-229, and Th-230
relative to Th-232 were measured. An overall efficiency including ionization,
transport and detection of 0.6 was determined, which was predominantly limited
by the transmission of the mass spectrometer ion optics
The Complexity of Computing Minimal Unidirectional Covering Sets
Given a binary dominance relation on a set of alternatives, a common thread
in the social sciences is to identify subsets of alternatives that satisfy
certain notions of stability. Examples can be found in areas as diverse as
voting theory, game theory, and argumentation theory. Brandt and Fischer [BF08]
proved that it is NP-hard to decide whether an alternative is contained in some
inclusion-minimal upward or downward covering set. For both problems, we raise
this lower bound to the Theta_{2}^{p} level of the polynomial hierarchy and
provide a Sigma_{2}^{p} upper bound. Relatedly, we show that a variety of other
natural problems regarding minimal or minimum-size covering sets are hard or
complete for either of NP, coNP, and Theta_{2}^{p}. An important consequence of
our results is that neither minimal upward nor minimal downward covering sets
(even when guaranteed to exist) can be computed in polynomial time unless P=NP.
This sharply contrasts with Brandt and Fischer's result that minimal
bidirectional covering sets (i.e., sets that are both minimal upward and
minimal downward covering sets) are polynomial-time computable.Comment: 27 pages, 7 figure
A New Look at the Axial Anomaly in Lattice QED with Wilson Fermions
By carrying out a systematic expansion of Feynman integrals in the lattice
spacing, we show that the axial anomaly in the U(1) lattice gauge theory with
Wilson fermions, as determined in one-loop order from an irrelevant lattice
operator in the Ward identity, must necessarily be identical to that computed
from the dimensionally regulated continuum Feynman integrals for the triangle
diagrams.Comment: 1 figure, LaTeX, 18 page
Feynman-Schwinger representation approach to nonperturbative physics
The Feynman-Schwinger representation provides a convenient framework for the
cal culation of nonperturbative propagators. In this paper we first investigate
an analytically solvable case, namely the scalar QED in 0+1 dimension. With
this toy model we illustrate how the formalism works. The analytic result for
the self energy is compared with the perturbative result. Next, using a
interaction, we discuss the regularization of various divergences
encountered in this formalism. The ultraviolet divergence, which is common in
standard perturbative field theory applications, is removed by using a
Pauli-Villars regularization. We show that the divergence associated with large
values of Feynman-Schwinger parameter is spurious and it can be avoided by
using an imaginary Feynman parameter .Comment: 26 pages, 9 figures, minor correctio
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