2,649 research outputs found
Spontaneous Parity Violation
We disprove the Vafa-Witten theorem on the impossibility of spontaneously
breaking parity in vector-like gauge field theories, identifying a mechanism
driven by quantum fluctuations. With the introduction of a meromorphic Lattice
formulation, defined over 5 dimensions, we demonstrate that the minima of the
free energy can be distinct from the maxima of the partition function :
identifying and evaluating a suitable contour for the partition function
defined such that asymptotic behaviour of the complex action is
non-oscillatory.Comment: 6 page
Lorentz Covariance and the Dimensional Crossover of 2d-Antiferromagnets
We derive a lattice -function for the 2d-Antiferromagnetic Heisenberg
model, which allows the lattice interaction couplings of the nonperturbative
Quantum Monte Carlo vacuum to be related directly to the zero-temperature fixed
points of the nonlinear sigma model in the presence of strong interplanar and
spin anisotropies. In addition to the usual renormalization of the gapful
disordered state in the vicinity of the quantum critical point, we show that
this leads to a chiral doubling of the spectra of excited states
Exact Nonperturbative Renormalization
We propose an exact renormalization group equation for Lattice Gauge
Theories, that has no dependence on the lattice spacing. We instead relate the
lattice spacing properties directly to the continuum convergence of the support
of each local plaquette. Equivalently, this is formulated as a convergence
prescription for a characteristic polynomial in the gauge coupling that allows
the exact meromorphic continuation of a nonperturbative system arbitrarily
close to the continuum limit.Comment: 12 page
The Lattice -function of Quantum Spin Chains
We derive the lattice -function for quantum spin chains, suitable for
relating finite temperature Monte Carlo data to the zero temperature fixed
points of the continuum nonlinear sigma model. Our main result is that the
asymptotic freedom of this lattice -function is responsible for the
nonintegrable singularity in , that prevents analytic continuation
between and .Comment: 10 page
The social geography of childcare: 'making up' the middle class child
Childcare is a condensate of disparate social forces and social processes. It is gendered and classed. It is subject to an excess of policy and political discourse. It is increasingly a focus for commercial exploitation. This is a paper reporting on work in progress in an ESRC funded research project (R000239232) on the choice and provision of pre-school childcare by middle class (service class) families in two contrasting London locations. Drawing on recent work in class analysis the paper examines the relationships between childcare choice, middle class fractions and locality. It suggests that on the evidence of the findings to date, there is some evidence of systematic differences between fractions in terms of values, perspectives and preferences for childcare, but a more powerful case for intra-class similarities, particularly when it comes to putting preferences into practice in the 'making up of a middle class child' through care and education
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