26,298 research outputs found
Large N lattice QCD and its extended strong-weak connection to the hypersphere
We calculate an effective Polyakov line action of QCD at large Nc and large
Nf from a combined lattice strong coupling and hopping expansion working to
second order in both, where the order is defined by the number of windings in
the Polyakov line. We compare with the action, truncated at the same order, of
continuum QCD on S^1 x S^d at weak coupling from one loop perturbation theory,
and find that a large Nc correspondence of equations of motion found in
\cite{Hollowood:2012nr} at leading order, can be extended to the next order.
Throughout the paper, we review the background necessary for computing higher
order corrections to the lattice effective action, in order to make higher
order comparisons more straightforward.Comment: 33 pages, 7 figure
The “True Man” and His Gun: On the Masculine Mystique of Second Amendment Jurisprudence
The Supreme Court’s recent Second Amendment jurisprudence raises serious normative questions for the use of self-defense with a firearm. This jurisprudence also implicates our prevailing social norms with respect to socially constructed and structurally pervasive gender roles. I argue that a peculiarly American conception of masculinity underpins the judicial construction of the Second Amendment’s core purpose as guaranteeing the right to armed defense of one’s self and one’s home. The Court’s recent Second Amendment rulings create an individual protection for gun ownership and incorporate the same against the States. But the Court’s reasoning entangles this protection with an implicit valuation of manhood that reifies the notion that “true men” do not retreat in the face of danger. In so entangling, the Court establishes a right to gun ownership that is politically free but legally male. This Article explores the socio-legal structures that underpin the Court’s reasoning to explain (a) how the right to keep and bear arms arises from a dubious ideal of the American “man,” and thus how (b) the purposes for which one may keep and bear arms galvanizes a particular masculine type within our Second Amendment jurisprudence. That type establishes a problematic cultural narrative of and ethos for manhood in America; consequently, this jurisprudence establishes a dominant masculinity predicated upon firearm ownership. That masculinity complicates, and may even impede, the social evolution of subordinated masculinities and shifts the social hierarchy of masculinities to empower and privilege gun-owning males
Calculating the chiral condensate diagrammatically at strong coupling
We calculate the chiral condensate of QCD at infinite coupling as a function
of the number of fundamental fermion flavours using a lattice diagrammatic
approach inspired by recent work of Tomboulis, and other work from the 80's. We
outline the approach where the diagrams are formed by combining a truncated
number of sub-diagram types in all possible ways. Our results show evidence of
convergence and agreement with simulation results at small Nf. However,
contrary to recent simulation results, we do not observe a transition at a
critical value of Nf. We further present preliminary results for the chiral
condensate of QCD with symmetric or adjoint representation fermions at infinite
coupling as a function of Nf for Nc = 3. In general, there are sources of error
in this approach associated with miscounting of overlapping diagrams, and
over-counting of diagrams due to symmetries. These are further elaborated upon
in a longer paper.Comment: presented at the 32nd International Symposium on Lattice Field Theory
(Lattice 2014), 23-28 June 2014, New York, NY, US
77Se NMR Investigation of the K(x)Fe(2-y)Se(2) High Tc Superconductor (Tc=33K)
We report a comprehensive 77Se NMR study of the structural, magnetic, and
superconducting properties of a single crystalline sample of the newly
discovered FeSe-based high temperature superconductor K(x)Fe(2-y)Se(2) (Tc=33K)
in a broad temperature range up to 290 K. We will compare our results with
those reported for FeSe (Tc=9K) and FeAs-based high Tc systems.Comment: Final versio
Numerical indications on the semiclassical limit of the flipped vertex
We introduce a technique for testing the semiclassical limit of a quantum
gravity vertex amplitude. The technique is based on the propagation of a
semiclassical wave packet. We apply this technique to the newly introduced
"flipped" vertex in loop quantum gravity, in order to test the intertwiner
dependence of the vertex. Under some drastic simplifications, we find very
preliminary, but surprisingly good numerical evidence for the correct classical
limit.Comment: 4 pages, 8 figure
Germinability Factors of Field-Grown Sorghum Seed
Germination of sorghum seed did not appear to be affected by spraying the plants with Maneb or with a chemical defoliant before harvest. Mechanical threshing greatly reduced germination of most but not all lots; this injury is thought to be related to the maturity and/ or moisture content of the seed when threshed, although other varietal differences may be important. At any given time there were large differences in moisture content between seeds of different hybrids, different plants of any one hybrid, and between different parts of the same panicle
Positivity of Spin Foam Amplitudes
The amplitude for a spin foam in the Barrett-Crane model of Riemannian
quantum gravity is given as a product over its vertices, edges and faces, with
one factor of the Riemannian 10j symbols appearing for each vertex, and simpler
factors for the edges and faces. We prove that these amplitudes are always
nonnegative for closed spin foams. As a corollary, all open spin foams going
between a fixed pair of spin networks have real amplitudes of the same sign.
This means one can use the Metropolis algorithm to compute expectation values
of observables in the Riemannian Barrett-Crane model, as in statistical
mechanics, even though this theory is based on a real-time (e^{iS}) rather than
imaginary-time (e^{-S}) path integral. Our proof uses the fact that when the
Riemannian 10j symbols are nonzero, their sign is positive or negative
depending on whether the sum of the ten spins is an integer or half-integer.
For the product of 10j symbols appearing in the amplitude for a closed spin
foam, these signs cancel. We conclude with some numerical evidence suggesting
that the Lorentzian 10j symbols are always nonnegative, which would imply
similar results for the Lorentzian Barrett-Crane model.Comment: 15 pages LaTeX. v3: Final version, with updated conclusions and other
minor changes. To appear in Classical and Quantum Gravity. v4: corrects # of
samples in Lorentzian tabl
The Concept of Psychological Distress and Its Assessment: A Clinimetric Analysis of the SCL-90-R
Many studies have been conducted on psychological distress but the question of how to conceptualize and assess this phenomenon still remains a controversial issue. Clinimetrics, the science of clinical measurements, may pave the ground for a substantial revision of the clinical conceptualization and assessment of this construct. A Rasch analysis was performed to evaluate whether the Symptom Checklist-90-Revised (SCL-90-R) and its subscales were valid indices of underlying dimensions of psychological distress. Based on the clinimetric validation of the SCL-90-R, as well as on a critical review of the available literature, a concept analysis of psychological distress was performed. The SCL-90-R total score misfitted the Rasch model but it was found to have a Person Separation Reliability Index of 0.94. Model fit was achieved after the exclusion of six misfitting items. Paired t tests indicated that all the subscales of the SCL-90-R were unidimensional. Psychological distress was defined as a subjective, unifying, dimensional, and transdiagnostic construct consisting in a unique experience of discomfort, which may involve a sense of demoralization, the experience of feeling broken or mental pain, a sense of anguish, symptoms of somatization and attention deficit hyperactivity disorder (ADHD), feelings of anger, self-perceived lack of control, and self-criticism. Our findings also showed that the SCL-90-R could reliably differentiate healthy stress from psychological distress, and identify individuals at risk of psychiatric disorders. The total score of the 84-item version of the SCL-90-R may be used as an overall indicator of psychological distress. The subscales are recommended to assess the severity of specific symptomatic manifestations of psychological distress
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