2,399 research outputs found
Renormalization group computation of likelihood functions for cosmological data sets
I show how a renormalization group (RG) method can be used to incrementally
integrate the information in cosmological large-scale structure data sets
(including CMB, galaxy redshift surveys, etc.). I show numerical tests for
Gaussian fields, where the method allows arbitrarily close to exact computation
of the likelihood function in order time, even for problems with no
symmetry, compared to for brute force linear algebra (where is the
number of data points -- to be fair, methods already exist to solve the
Gaussian problem in at worst time, and this method will not
necessarily be faster in practice). The method requires no sampling or other
Monte Carlo (random) element. Non-linearity/non-Gaussianity can be accounted
for to the extent that terms generated by integrating out small scale modes can
be projected onto a sufficient basis, e.g., at least in the sufficiently
perturbative regime. The formulas to evaluate are straightforward and require
no understanding of quantum field theory, but this paper may also serve as a
pedagogical introduction to Wilsonian RG for astronomers.Comment: 13 pg, 4 fi
Vector Superfields and Lorentz Violation
We extend Lorentz-violating Supersymmetry models to include vector
superfields. The CPT-preserving model generalizes easily, while the obvious
attempt at generalizing the CPT-violating model meets serious obstructions.
Generalizations of the CPT-preserving but Lorentz-Violating model to higher
dimensions are also straightforward. Compactification is used to reduce the
six-dimensional theory to an Lorentz-violating theory in four
dimensions, while the ten-dimensional theory is used to produce an
Lorentz-violating theory. This may be useful in future
constructions involving Ads/CFT correspondence with Lorentz violation.Comment: 5 pages, submitted to Physical Review
Lorentz Violation and Extended Supersymmetry
We construct a collection of Lorentz violating Yang-Mills theories exhibiting
supersymmetry.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Nonrelativisitic Ideal Gasses and Lorentz Violations
We develop statistical mechanics for a nonrelativisitic ideal gas in the
presence of Lorentz violating background fields. The analysis is performed
using the Standard-Model Extension (SME). We derive the corresponding laws of
thermodynamics and find that, to lowest order in Lorentz violation, the scalar
thermodynamic variables are corrected by a rotationally invariant combination
of the Lorentz terms which can be interpreted in terms of a (frame dependent)
effective mass. We find that spin couplings can induce a temperature
independent polarization in the gas that is not present in the conventional
case.Comment: 6 pages, proceedings for CPT and Lorentz Symmetry, Bloomington, IN,
200
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