5,403 research outputs found
Monopoles, vortices and confinement in SU(3) gauge theory
We compute, in SU(3) pure gauge theory, the vacuum expectation value (vev) of
the operator which creates a vortex wrapping the lattice through periodic
boundary conditions (dual Polyakov line). The technique used is the same
already tested in the SU(2) case. The dual Polyakov line proves to be a good
disorder parameter for confinement, and has a similar behaviour to the monopole
condensate. The new features which characterise the construction of the
disorder operator in SU(3) are emphasised.Comment: 8 pages, 4 eps figures, typed with elsart.cl
Chiral transition and deconfinement in N_f = 2 QCD
The transition is studied by means of a disorder parameter detecting
condensation of magnetic monopoles in the vacuum. The deconfining transition is
found to coincide with the chiral transition and the susceptibility \rho,
related to the disorder parameter, is consistent with a first order phase
transition.Comment: 3 pages, 2 figures. Poster presented at Lattice2004(topology),
Fermilab, June 21-26, 200
Family Networks and School Enrolment: Evidence from a Randomized Social Experiment
We present evidence on whether and how a household's behavior is influenced by the presence and characteristics of its extended family. Using data from the PROGRESA program in Mexico, we exploit information on the paternal and maternal surnames of heads and spouses in conjunction with the Spanish naming convention to identify the inter and intra generational family links of each household to others in the same village. We then exploit the randomized research design of the PROGRESA evaluation data to identify whether the treatment effects of PROGRESA transfers on secondary school enrolment vary according to the characteristics of extended family. We find PROGRESA only raises secondary enrolment among households that are embedded in a family network. Eligible but isolated households do not respond. The mechanism through which the extended family influences household schooling choices is the redistribution of resources within the family network from eligibles that receive de facto unconditional cash transfers from PROGRESA, towards eligibles on the margin of enrolling children into secondary school.extended family network, PROGRESA, resource sharing, schooling
Extended Family Networks in Rural Mexico: A Descriptive Analysis
We provide descriptive evidence on the characteristics of a householdâs extended family network using data from the Progresa social assistance program in rural Mexico. We exploit information on the paternal and maternal surnames of household heads and their spouses and the patronymic naming convention to identify the inter and intra generational family links of each household to others in the village. This provides an almost complete mapping of extended family networks structures across 506 Mexican villages, covering 22,000 households and over 130,000 individuals. We then provide evidence on â (i) whether husbands and wives differ in the extent to which members of their extended family are located in geographic proximity; (ii) the characteristics that predict the existence of extended family links; (iii) the similarity of households within the same family network in terms of their poverty, and how this differs within and between generations of the extended family.extended family network, Progresa
Village Economies and the Structure of Extended Family Networks
This paper documents how the structure of extended family networks in rural Mexico relates to the poverty and inequality of the village of residence. Using the Hispanic naming convention, we construct within-village extended family networks in 504 poor rural villages. Family networks are larger (both in the number of members and as a share of the village population) and out-migration is lower the poorer and the less unequal the village of residence. Our results are consistent with the extended family being a source of informal insurance to its members.extended family network, migration, village inequality, village marginality
Topological properties of full QCD at the phase transition
We investigate the topological properties of the QCD vacuum with 4 flavours
of dynamical staggered fermions at finite temperature. To calculate the
topological susceptibility we use the field-theoretical method. As in the
quenched case, a sharp drop is observed for the topological susceptibility
across the phase transition.Comment: LATTICE98(confine
Mutual Inductance Route to Paramagnetic Meissner Effect in 2D Josephson Junction Arrays
We simulate two-dimensional Josephson junction arrays, including full mutual-
inductance effects, as they are cooled below the transition temperature in a
magnetic field. We show numerical simulations of the array magnetization as a
function of position, as detected by a scanning SQUID which is placed at a
fixed height above the array. The calculated magnetization images show striking
agreement with the experimental images obtained by A. Nielsen et al. The
average array magnetization is found to be paramagnetic for many values of the
applied field, confirming that paramagnetism can arise from magnetic screening
in multiply-connected superconductors without the presence of d-wave
superconductivity.Comment: REVTeX 3.1, 5 pages, 5 figure
Orofacial functions and chewing effiency in elderly patients with parkinsonâs disease rehabilitated with removable prostheses
The squashed entanglement of the noiseless quantum Gaussian attenuator and amplifier
We determine the maximum squashed entanglement achievable between sender and
receiver of the noiseless quantum Gaussian attenuators and amplifiers and we
prove that it is achieved sending half of an infinitely squeezed two-mode
vacuum state. The key ingredient of the proof is a lower bound to the squashed
entanglement of the quantum Gaussian states obtained applying a two-mode
squeezing operation to a quantum thermal Gaussian state tensored with the
vacuum state. This is the first lower bound to the squashed entanglement of a
quantum Gaussian state and opens the way to determine the squashed entanglement
of all quantum Gaussian channels. Moreover, we determine the classical squashed
entanglement of the quantum Gaussian states above and show that it is strictly
larger than their squashed entanglement. This is the first time that the
classical squashed entanglement of a mixed quantum Gaussian state is
determined
Color confinement and dual superconductivity of the vacuum. III
It is demonstrated that monopole condensation in the confined phase of SU(2)
and SU(3) gauge theories is independent of the specific Abelian projection used
to define the monopoles. Hence the dual excitations which condense in the
vacuum to produce confinement must have magnetic U(1) charge in all the Abelian
projections. Some physical implications of this result are discussed.Comment: 6 pages, 5 postscript figure
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