Local gauge symmetry on optical lattices?

The versatile technology of cold atoms confined in optical lattices allows the creation of a vast number of lattice geometries and interactions, providing a promising platform for emulating various lattice models. This opens the possibility of letting nature take care of sign problems and real time evolution in carefully prepared situations. Up to now, experimentalists have succeeded to implement several types of Hubbard models considered by condensed matter theorists. In this proceeding, we discuss the possibility of extending this effort to lattice gauge theory. We report recent efforts to establish the strong coupling equivalence between the Fermi Hubbard model and SU(2) pure gauge theory in 2+1 dimensions by standard determinantal methods developed by Robert Sugar and collaborators. We discuss the possibility of using dipolar molecules and external fields to build models where the equivalence holds beyond the leading order in the strong coupling expansion.Comment: 6 pages, 3 figures,poster presented at the 30th International Symposium on Lattice Field Theory, June 24 - 29, 2012, Cairns, Australi

Finite size scaling of conformal theories in the presence of a near-marginal operator

The slowly evolving gauge coupling of gauge-fermion systems near the conformal window makes numerical investigations of these models challenging. We consider finite size scaling and show that this often used technique leads to inconsistent results if the leading order scaling corrections are neglected. When the corrections are included the results become consistent not only between different operators but even when data obtained at different gauge couplings or with different lattice actions are combined. Our results indicate that the SU(3) 12-fermion system is conformal with mass anomalous dimension $\gamma_m=0.235(15)$

Mortality of the Oldest Old in China

Objective: This study investigates the role of customary activities, both social and solitary, in mortality among the oldest old in China. Methods: The data come from the Chinese Longitudinal Healthy Longevity Survey.Weibull hazard models analyze the mortality risk of those 80 years of age and older within a 2-year period between 1998 and 2000. Results: Results show that solitary activities, either active or sedentary, are significantly associated with lower mortality risk. The effect of social activities on mortality gradually diminishes with age and is reversed at very old ages when physical exercise, health status, and sociodemographic characteristics are controlled. Discussion: Customary activities, which are less physically demanding, show independent effects on the elderly’s survival.Withdrawal from social contacts may be an adaptive response to challenges faced at very advanced ages. It is important to recognize the unique characteristics of this rapidly growing population

Improving the continuum limit of gradient flow step scaling

We introduce a non-perturbative improvement for the renormalization group step scaling function based on the gradient flow running coupling, which may be applied to any lattice gauge theory of interest. Considering first SU(3) gauge theory with $N_f = 4$ massless staggered fermions, we demonstrate that this improvement can remove $O(a^2)$ lattice artifacts, and thereby increases our control over the continuum extrapolation. Turning to the 12-flavor system, we observe an infrared fixed point in the infinite-volume continuum limit. Applying our proposed improvement reinforces this conclusion by removing all observable $O(a^2)$ effects. For the finite-volume gradient flow renormalization scheme defined by $c = \sqrt{8t} / L = 0.2$, we find the continuum conformal fixed point to be located at $g_\star^2 = 6.2(2)$Comment: 12 pages, 4 figures; Minor changes, published versio