Density Functional Theory Studies of Magnetically Confined Fermi Gas

A theory is developed for magnetically confined Fermi gas at low temperature based on the density functional theory. The theory is illustrated by numerical calculation of density distributions of Fermi atoms $^{40}$K with parameters according to DeMarco and Jin's experiment[Science, 285(1999)1703]. Our results are in good agreement with the experiment. To check the theory, we also performed calculations using our theory at high temperature and compared very well to the result of classical limit.Comment: 6 page

Andreev Bound states in One Dimensional Topological Superconductor

We study the charge character of the Andreev bound states (ABSs) in one-dimensional topological superconductors with spatial inversion symmetry (SIS) breaking. Despite the absence of the SIS, we show a hidden symmetry for the Bogoliubov de Gennes equations around Fermi points in addition to the particle-hole symmetry. This hidden symmetry protects that the charge of the ABSs is solely dependent on the corresponding Fermi velocities. On the other hand, if the SIS is present, the ABSs are charge neutral, similar to Majorana fermions. We demonstrate that the charge of the ABSs can be experimentally measured in the tunneling transport spectroscopy from the resonant differential tunneling conductance.Comment: 4 pages plus appendix; 4 figure

Competition, Innovation and Racing for Priority at the U.S. Patent and Trademark Office

The U.S. Patent and Trademark Office resolves patent priority disputes in patent interference cases. Using a random sample of cases declared between 1988 and 1994, we establish a connection between patent interferences and patent races, and then use the data to consider some key issues in dynamic competition and innovation. We look at the incidence and distribution of patent races by technology, evidence for strategic delay of innovation by incumbent firms, and evidence that patent races moderate incentives to delay. Our results have implications for patent policy in general and for evaluating the U.S. “first to invent†patent priority rule.Patent race, Patent interference, US Board of Patent Appeals and Interferences, Patent litigation; Innovation; Research and development