20,634 research outputs found
Heavy Quark Potential from Gauge/Gravity Duality: A Large D Analysis
The heavy-quark potential is calculated in the framework of gauge/gravity
duality using the large-D approximation, where D is the number of dimensions
transverse to the flux tube connecting a quark and an antiquark in a flat
D+2-dimensional spacetime. We find that in the large-D limit the leading
correction to the ground-state energy, as given by an effective Nambu-Goto
string, arises not from the heavy modes but from the behavior of the massless
modes in the vicinity of the quark and the antiquark. We estimate this
correction and find that it should be visible in the near-future lattice QCD
calculations of the heavy-quark potential.Comment: 22 pages, 5 Figures. v2: references added, typos corrected and, Sec.
4 rewritten with an expanded non-perturbative discussion of the corrections
to the Arvis potential arising from the massless modes near the boundary of
the qcd strin
Fermionization, Convergent Perturbation Theory, and Correlations in the Yang-Mills Quantum Field Theory in Four Dimensions
We show that the Yang-Mills quantum field theory with momentum and spacetime
cutoffs in four Euclidean dimensions is equivalent, term by term in an
appropriately resummed perturbation theory, to a Fermionic theory with nonlocal
interaction terms. When a further momentum cutoff is imposed, this Fermionic
theory has a convergent perturbation expansion. To zeroth order in this
perturbation expansion, the correlation function of generic components
of pairs of connections is given by an explicit, finite-dimensional integral
formula, which we conjecture will behave as \noindent for where is a positive integer depending
on the gauge group In the case where we conjecture that \noindent so that the rate
of decay of correlations increases as Comment: Minor corrections of notation, style and arithmetic errors;
correction of minor gap in the proof of Proposition 1.4 (the statement of the
Proposition was correct); further remark and references adde
Assessing Legal Responses to Prenatal Drug Use: Can Therapeutic Responses Produce More Positive Outcomes than Punitive Responses
Expressing a growing concern for fetal well being, the 2006 Idaho Senate passed legislation that permits criminal charges to be brought against women who abuse illegal drugs while pregnant. This bill allows for the potential incarceration of violators for up to five years, as well as a possible $50,000 fine. In some locations, women have the option of choosing to go to drug court instead of serving time in jail or prison. These drug courts provide drug treatment, case management, drug testing, and supervision, while requiring women who abuse illegal drugs to regularly report to scheduled status hearings before a judge. Legislators, such as Idaho Senator Kate Kelly, have criticized these laws for being punitive. Such critics believe that addiction to methamphetamine is an illness and not a crime. Some critics are also concerned about the law\u27s effects on families. Senator Kelly also said, [c]riminalization of substance abuse, [and] the separation of infants from their mother, is not in the best interest of Idaho families. In other words, punitive measures are not necessarily the best policies; other options should be considered first. Also, Senator Denton Darrington stated [t]he goal of this legislation is to avoid the birth of meth babies. . . . While the current legal actions taken against prenatal substance abusers are intended to produce positive outcomes, such as healthier fetuses and mothers, negative results are possible. Avoidance of prenatal care, constitutional infringements, and discrimination are just a few of the possible negative effects. For example, while legislatures hope the new Idaho law will prevent prenatal drug abuse, experts fear that pregnant drug users will not seek prenatal care for fear of being prosecuted
Assessing Legal Responses to Prenatal Drug Use: Can Therapeutic Responses Produce More Positive Outcomes than Punitive Responses
Expressing a growing concern for fetal well being, the 2006 Idaho Senate passed legislation that permits criminal charges to be brought against women who abuse illegal drugs while pregnant. This bill allows for the potential incarceration of violators for up to five years, as well as a possible $50,000 fine. In some locations, women have the option of choosing to go to drug court instead of serving time in jail or prison. These drug courts provide drug treatment, case management, drug testing, and supervision, while requiring women who abuse illegal drugs to regularly report to scheduled status hearings before a judge. Legislators, such as Idaho Senator Kate Kelly, have criticized these laws for being punitive. Such critics believe that addiction to methamphetamine is an illness and not a crime. Some critics are also concerned about the law\u27s effects on families. Senator Kelly also said, [c]riminalization of substance abuse, [and] the separation of infants from their mother, is not in the best interest of Idaho families. In other words, punitive measures are not necessarily the best policies; other options should be considered first. Also, Senator Denton Darrington stated [t]he goal of this legislation is to avoid the birth of meth babies. . . . While the current legal actions taken against prenatal substance abusers are intended to produce positive outcomes, such as healthier fetuses and mothers, negative results are possible. Avoidance of prenatal care, constitutional infringements, and discrimination are just a few of the possible negative effects. For example, while legislatures hope the new Idaho law will prevent prenatal drug abuse, experts fear that pregnant drug users will not seek prenatal care for fear of being prosecuted
Regularized Green's Function for the Inverse Square Potential
A Green's function approach is presented for the D-dimensional inverse square
potential in quantum mechanics. This approach is implemented by the
introduction of hyperspherical coordinates and the use of a real-space
regulator in the regularized version of the model. The application of
Sturm-Liouville theory yields a closed expression for the radial energy Green's
function. Finally, the equivalence with a recent path-integral treatment of the
same problem is explicitly shown.Comment: 10 pages. The final section was expande
Vacuum decay and internal symmetries
We study the effects of internal symmetries on the decay by bubble nucleation
of a metastable false vacuum. The zero modes about the bounce solution that are
associated with the breaking of continuous internal symmetries result in an
enhancement of the tunneling rate into vacua in which some of the symmetries of
the initial state are spontaneously broken. We develop a general formalism for
evaluating the effects of these zero modes on the bubble nucleation rate in
both flat and curved space-times.Comment: LaTex, 11 pages, No figures, one minor chang
wormholes and topological charge
I investigate solutions to the Euclidean Einstein-matter field equations with
topology in a theory with a massless periodic scalar
field and electromagnetism. These solutions carry winding number of the
periodic scalar as well as magnetic flux. They induce violations of a
quasi-topological conservation law which conserves the product of magnetic flux
and winding number on the background spacetime. I extend these solutions to a
model with stable loops of superconducting cosmic string, and interpret them as
contributing to the decay of such loops.Comment: 18 pages (includes 6 figs.), harvmac and epsf, CU-TP-62
Minisuperspace Model for Revised Canonical Quantum Gravity
We present a reformulation of the canonical quantization of gravity, as
referred to the minisuperspace; the new approach is based on fixing a Gaussian
(or synchronous) reference frame and then quantizing the system via the
reconstruction of a suitable constraint; then the quantum dynamics is re-stated
in a generic coordinates system and it becomes dependent on the lapse function.
The analysis follows a parallelism with the case of the non-relativistic
particle and leads to the minisuperspace implementation of the so-called {\em
kinematical action} as proposed in \cite{M02} (here almost coinciding also with
the approach presented in \cite{KT91}). The new constraint leads to a
Schr\"odinger equation for the system. i.e. to non-vanishing eigenvalues for
the super-Hamiltonian operator; the physical interpretation of this feature
relies on the appearance of a ``dust fluid'' (non-positive definite) energy
density, i.e. a kind of ``materialization'' of the reference frame. As an
example of minisuperspace model, we consider a Bianchi type IX Universe, for
which some dynamical implications of the revised canonical quantum gravity are
discussed. We also show how, on the classical limit, the presence of the dust
fluid can have relevant cosmological issues. Finally we upgrade our analysis by
its extension to the generic cosmological solution, which is performed in the
so-called long-wavelength approximation. In fact, near the Big-Bang, we can
neglect the spatial gradients of the dynamical variables and arrive to
implement, in each space point, the same minisuperspace paradigm valid for the
Bianchi IX model.Comment: 16 pages, no figures, to appear on International Journal of Modern
Physics
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