11,299 research outputs found
Wavelets in Field Theory
We advocate the use of Daubechies wavelets as a basis for treating a variety
of problems in quantum field theory. This basis has both natural large volume
and short distance cutoffs, has natural partitions of unity, and the basis
functions are all related to the fixed point of a linear renormalization group
equation.Comment: 42 pages, 2 figures, corrected typo
A Theorem on Light-Front Quantum Models
I give a sufficient condition for a relativistic front-form quantum
mechanical model to be scattering equivalent (unitarily equivalent with the
same S-matrix elements) to a relativistic front-form quantum model with an
interaction-independent front-form spin.Comment: 22 pages, (TeX + PHYZZX macros
The Maximum B-mode Polarization of the Cosmic Microwave Background from Inhomogeneous Reionization
We compute the B-mode polarization power spectrum of the CMB from an epoch of
inhomogeneous reionization, using a simple model in which HII regions are
represented by ionized spherical bubbles with a log normal distribution of
sizes whose clustering properties are determined by large-scale structure. Both
the global ionization fraction and the characteristic radius of HII regions are
allowed to be free functions of redshift. Models that would produce substantial
contamination to degree scale gravitational wave B-mode measurements have power
that is dominated by the shot noise of the bubbles. Rare bubbles of >100 Mpc at
z>20 can produce signals that in fact exceed the B-modes from gravitational
lensing and are comparable to the maximal allowed signal of gravitational waves
(~0.1uK) while still being consistent with global constraints on the total
optical depth. Even bubbles down to 20 Mpc at z~15, or 40 Mpc at z~10 can be
relevant (0.01uK) once the lensing signal is removed either statistically or
directly. However, currently favored theoretical models that have ionization
bubbles that only grow to such sizes at the very end of a fairly prompt and
late reionization produce signals which are at most at these levels.Comment: 14 pages, 11 figures; published in ApJ; corrected Fig. 4 and updated
reference
Hidden spin current in doped Mott antiferromagnets
We investigate the nature of doped Mott insulators using exact
diagonalization and density matrix renormalization group methods. Persistent
spin currents are revealed in the ground state, which are concomitant with a
nonzero total momentum or angular momentum associated with the doped hole. The
latter determines a nontrivial ground state degeneracy. By further making
superpositions of the degenerate ground states with zero or unidirectional spin
currents, we show that different patterns of spatial charge and spin
modulations will emerge. Such anomaly persists for the odd numbers of holes,
but the spin current, ground state degeneracy, and charge/spin modulations
completely disappear for even numbers of holes, with the two-hole ground state
exhibiting a d-wave symmetry. An understanding of the spin current due to a
many-body Berry-like phase and its impact on the momentum distribution of the
doped holes will be discussed.Comment: 9 pages, 9 figures, update second version including more data and
discussion adde
Employeesâ Financial Insecurity and Health: The Underlying Role of Stress and WorkâFamily Conflict Appraisals
Data from two longitudinal samples were utilized to elucidate underlying mechanisms of the wellâestablished relationship between financial insecurity and health outcomes, stemming from the theoretical rationale of conservation of resources and cognitive appraisal theories. Study 1 (n = 80) consisted of lowâwage food manufacturing employees working full time, while Study 2 (n = 331) was consisted of a larger, heterogeneous sample of fullâtime workers representing multiple occupations. Respondents were surveyed on financial insecurity, workâtoâfamily conflict (WFC), stress, and health outcomes at two time periods, 3 months apart. Results across our studies provided support for the direct effects of financial insecurity on WFC and stress. In addition, appraisals of WFC and stress serve as significant mediators of the relationship between financial insecurity and health outcomes, including a significant overall lagged effect across time, and perceived stress accounting for the largest proportion of variance in the lagged relationship among Time 1 financial insecurity and Time 2 health outcomes. Besides support for conservation of resources and cognitive appraisal theories, practically, our studies suggest that workplace initiatives to reduce financial insecurity could positively influence employeesâ workâfamily, stress, and health experiences
ANALYZING THE ECONOMIC IMPACT OF NATIONAL BEEF IMPORT LEVEL CHANGES ON THE VIRGINIA BEEF AND PORK SECTORS
International Relations/Trade,
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