40,015 research outputs found
Permutation Symmetric Critical Phases in Disordered Non-Abelian Anyonic Chains
Topological phases supporting non-abelian anyonic excitations have been
proposed as candidates for topological quantum computation. In this paper, we
study disordered non-abelian anyonic chains based on the quantum groups
, a hierarchy that includes the FQH state and the proposed
Fibonacci state, among others. We find that for odd these
anyonic chains realize infinite randomness critical {\it phases} in the same
universality class as the permutation symmetric multi-critical points of
Damle and Huse (Phys. Rev. Lett. 89, 277203 (2002)). Indeed, we show that the
pertinent subspace of these anyonic chains actually sits inside the symmetric sector of the Damle-Huse model, and this symmetry stabilizes the phase.Comment: 13 page
Perturbation Theory of Coulomb Gauge Yang-Mills Theory Within the First Order Formalism
Perturbative Coulomb gauge Yang-Mills theory within the first order formalism
is considered. Using a differential equation technique and dimensional
regularization, analytic results for both the ultraviolet divergent and finite
parts of the two-point functions at one-loop order are derived. It is shown how
the non-ultraviolet divergent parts of the results are finite at spacelike
momenta with kinematical singularities on the light-cone and subsequent branch
cuts extending into the timelike region.Comment: 23 pages, 6 figure
Relative distributions of W's and Z's at low transverse momenta
Despite large uncertainties in the and transverse momentum
() distributions for q_T\lsim 10 GeV, the ratio of the distributions
varys little. The uncertainty in the ratio of to distributions is
on the order of a few percent, independent of the details of the
nonperturbative parameterization.Comment: 13 pages in revtex, 5 postscript figures available upon request,
UIOWA-94-0
Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial
OBJECTIVE: To investigate the effect of bracket-ligature combination on the amount of orthodontic space closure over three months. DESIGN: Randomized clinical trial with three parallel groups. SETTING: A hospital orthodontic department (Chesterfield Royal Hospital, UK). PARTICIPANTS: Forty-five patients requiring upper first premolar extractions. METHODS: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick((R)) low friction elastomeric ligatures; (3) Damon 3MX((R)) passive self-ligating brackets. Space closure was undertaken on 0.019x0.025-inch stainless steel archwires with nickel-titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period. RESULTS: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P = 0.718). CONCLUSION: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response
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Federal Programs Available to Unemployed Workers
[Excerpt] Four groups of federal programs target unemployed workers: unemployment insurance programs, health care assistance, job search assistance, and training. This report describes these programs, how they interact with each other, and their funding.
Unemployed workers and their families may experience substantial income loss. If the unemployed worker’s family income is low enough, there are a number of means-tested benefits and programs for which the unemployed worker’s family might qualify (e.g., Temporary Assistance for Needy Families, SSI, or Medicaid). Eligibility for such benefits is not conditional on an individual’s current employment status. This report does not attempt to discuss these means-tested benefits and programs
Mixed state Pauli channel parameter estimation
The accuracy of any physical scheme used to estimate the parameter describing
the strength of a single qubit Pauli channel can be quantified using standard
techniques from quantum estimation theory. It is known that the optimal
estimation scheme, with m channel invocations, uses initial states for the
systems which are pure and unentangled and provides an uncertainty of
O[1/m^(1/2)]. This protocol is analogous to a classical repetition and
averaging scheme. We consider estimation schemes where the initial states
available are not pure and compare a protocol involving quantum correlated
states to independent state protocols analogous to classical repetition
schemes. We show, that unlike the pure state case, the quantum correlated state
protocol can yield greater estimation accuracy than any independent state
protocol. We show that these gains persist even when the system states are
separable and, in some cases, when quantum discord is absent after channel
invocation. We describe the relevance of these protocols to nuclear magnetic
resonance measurements
Subwavelength atom localization via amplitude and phase control of the absorption spectrum
We propose a scheme for subwavelength localization of an atom conditioned
upon the absorption of a weak probe field at a particular frequency.
Manipulating atom-field interaction on a certain transition by applying drive
fields on nearby coupled transitions leads to interesting effects in the
absorption spectrum of the weak probe field. We exploit this fact and employ a
four-level system with three driving fields and a weak probe field, where one
of the drive fields is a standing-wave field of a cavity. We show that the
position of an atom along this standing wave is determined when probe field
absorption is measured. We find that absorption of the weak probe field at a
certain frequency leads to subwavelength localization of the atom in either of
the two half-wavelength regions of the cavity field by appropriate choice of
the system parameters. We term this result as sub-half-wavelength localization
to contrast it with the usual atom localization result of four peaks spread
over one wavelength of the standing wave. We observe two localization peaks in
either of the two half-wavelength regions along the cavity axis.Comment: Accepted for publication to Physical Review
Chiral dynamics in form factors, spectral-function sum rules, meson-meson scattering and semilocal duality
In this work, we perform the one-loop calculation of the scalar and
pseudoscalar form factors in the framework of U(3) chiral perturbation theory
with explicit tree level exchanges of resonances. The meson-meson scattering
calculation from Ref.[1] is extended as well. The spectral functions of the
nonet scalar-scalar (SS) and pseudoscalar-pseudoscalar (PP) correlators are
constructed by using the corresponding form factors. After fitting the unknown
parameters to the scattering data, we discuss the resonance content of the
resulting scattering amplitudes. We also study spectral-function sum rules in
the SS-SS, PP-PP and SS-PP sectors as well as semi-local duality from
scattering. The former relate the scalar and pseudoscalar spectra between
themselves while the latter mainly connects the scalar spectrum with the vector
one. Finally we investigate these items as a function of Nc for Nc > 3. All
these results pose strong constraints on the scalar dynamics and spectroscopy
that are discussed. They are successfully fulfilled by our meson-meson
scattering amplitudes and spectral functions.Comment: 45 pages, 17 figures and 4 tables. To match the published version in
PRD: a new paragraph is added in the Introduction and two new references are
include
Breeding habits and habitats of the amphibians of the Edwin S. George Reserve, Michigan, with notes on the local distribution of fishes
http://deepblue.lib.umich.edu/bitstream/2027.42/57122/1/OP686.pd
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