62,095 research outputs found
Non-probabilistic proof of the A_2 theorem, and sharp weighted bounds for the q-variation of singular integrals
Any Calderon-Zygmund operator T is pointwise dominated by a convergent sum of
positive dyadic operators. We give an elementary self-contained proof of this
fact, which is simpler than the probabilistic arguments used for all previous
results in this direction. Our argument also applies to the q-variation of
certain Calderon-Zygmund operators, a stronger nonlinearity than the maximal
truncations. As an application, we obtain new sharp weighted inequalities.Comment: 10 page
Erratum: algebraic spin liquid as the mother of many competing orders
We correct an error in our paper Phys. Rev. B 72, 104404 (2005)
[cond-mat/0502215]. We show that a particular fermion bilinear is not related
to the other ``competing orders'' of the algebraic spin liquid, and does not
possess their slowly decaying correlations. For the square lattice staggered
flux spin liquid (equivalently, d-wave RVB state), this observable corresponds
to the uniform spin chirality.Comment: 1.25 page
Family Size and the Distribution of Per Capita Income
This paper is another contribution to the vast literature which addresses this issue: comparison of household income per capita among households of different structures requires judgment about the relationship between real income and family size. Our work uses a revealed preference approach in which household size/structure variables are included in empirical demand studies and the estimated coefficients on these variables are used to infer equivalence; it differs from many of the other studies not in basic concept but in its empirical strategy. While most studies build family composition effects into a relatively formal structural model of demand and impose considerable restriction in order to obtain an estimable system, we use a reduced-form approach which requires much less of the data.
Orbitally excited and hybrid mesons from the lattice
We discuss in general the construction of gauge-invariant non-local meson
operators on the lattice. We use such operators to study the - and -wave
mesons as well as hybrid mesons in quenched QCD, with quark masses near the
strange quark mass. The resulting spectra are compared with experiment for the
orbital excitations. For the states produced by gluonic excitations (hybrid
mesons) we find evidence of mixing for non-exotic quantum numbers. We give
predictions for masses of the spin-exotic hybrid mesons with $J^{PC}=1^{-+},\
0^{+-}2^{+-}$.Comment: 31 pages, LATEX, 8 postscript figures. Reference adde
Finite isospin density probe for conformality
A new method of employing an isospin chemical potential for QCD-like theories
with different number of colors, number of fermion flavors, and in different
fermion representations is proposed. The isospin chemical potential, which can
be simulated on the lattice due to its positive definite determinant gives a
means to probe both confining theories and IR conformal theories without
adjusting the lattice spacing and size. As the quark mass is reduced, the
isospin chemical potential provides an avenue to extract the chiral condensate
in confining theories through the resulting pseudoscalar condensate. For IR
conformal theories, the mass anomalous dimension can be extracted in the
conformal window through "finite density" scaling since the isospin chemical
potential is coupled to a conserved current. In both of these approaches, the
isospin chemical potential can be continuously varied for each ensemble at
comparable costs while maintaining the hierarchy between the lattice size and
lattice spacing. In addition to exploring these methods, finite volume and
lattice spacing effects are investigated.Comment: 18 pages, 3 figures, v3: typos corrected and discussions improved.
Phys. Rev. D 85, 074503 (2012
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