3,121 research outputs found
Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation
We study the T=0 normal to superconducting transition of Josephson arrays
with {\it on-site} dissipation. A perturbative renormalization group solution
is given. Like the previously studied case of {\it bond} dissipation (BD), this
is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD
transition, at which {\it only} nearest-neighbor couplings become relevant,
here {\it all} inter-grain couplings, out to {\it infinitely} large distances,
do so simultaneously. We predict, for the first time in an FC transition, a
diverging spatial correlation length. Our results show the robustness of
floating phases in dissipative quantum systems.Comment: 7+ pages, 3 eps figures, Europhysics Letters preprint format, as
publishe
Ground state of Li and Be using explicitly correlated functions
We compare the explicitly correlated Hylleraas and exponential basis sets in
the evaluations of ground state of Li and Be. Calculations with Hylleraas
functions are numerically stable and can be performed with the large number of
basis functions. Our results for ground state energies , of Li and Be correspondingly, are the
most accurate to date. When small basis set is considered, explicitly
correlated exponential functions are much more effective. With only 128
functions we obtained about relative accuracy, but the severe
numerical instabilities make this basis costly in the evaluation.Comment: 15 page
- …