Searcharxiv⌕ Search

arXiv subjects

S. Dürr

Publications and source records attributed to S. Dürr.

22 records · Page 2Linked to original sources
arXiv2004

A comparative study of overlap and staggered fermions in QCD

We perform a comparative study of the infrared properties of overlap and staggered fermions in QCD. We observe that the infrared spectrum of the APE/HYP improved staggered Dirac operator develops a four-fold near-degeneracy and is in quantitative agreement with the infrared spectrum of the overlap operator. The near-degeneracy allows us to identify the zero modes of the staggered operator and we find that the number of zero modes is in line with the topological index of the overlap operator.

hep-lat↗
arXiv2003

Exploring two non-perturbative definitions of $c_A$

We present two determinations of the coefficient $c_A$ in quenched QCD, needed to build the $O(a)$ improved axial current. The first condition used is the requirement that the PCAC quark mass, as a function of $x_0$, stays flat for a non-trivial spatial phase for the fermions in the Schrödinger functional. The second condition is that the PCAC relation for the ground-state and the first excited state at finite L give the same quark mass. Our results confirm previous findings that in the quenched theory the intrinsic $O(a)$ ambiguity of $c_A$ gets relevant around $β\simeq6.0$.

hep-lat↗
arXiv2002

Feshbach resonances in rubidium 87: Precision measurement and analysis

More than 40 Feshbach resonances in rubidium 87 are observed in the magnetic field range between 0.5 and 1260 G for various spin mixtures in the lower hyperfine ground state. The Feshbach resonances are observed by monitoring the atom loss, and their positions are determined with an accuracy of 30 mG. In a detailed analysis, the resonances are identified and an improved set of model parameters for the rubidium interatomic potential is deduced. The elastic width of the broadest resonance at 1007 G is predicted to be significantly larger than the magnetic field resolution of the apparatus. This demonstrates the potential for applications based on tuning the scattering length.

cond-mat.stat-mech↗