Biomedical subjects

Daniel Ueltschi

Publications and source records attributed to Daniel Ueltschi.

2 recordsLinked to original sources

PubMed2006

Relation between Feynman cycles and off-diagonal long-range order.

The usual order parameter for Bose-Einstein condensation involves the off-diagonal correlation function of Penrose and Onsager, but an alternative is Feynman's notion of infinite cycles. We present a formula that relates both order parameters. We discuss its validity with the help of rigorous results and heuristic arguments. The conclusion is that infinite cycles do not always represent the Bose condensate.

Journal Article↗

PubMed2002

Phase separation due to quantum mechanical correlations.

Can phase separation be induced by strong electron correlations? We present a theorem that affirmatively answers this question in the Falicov-Kimball model away from half filling, for any dimension. In the ground state the itinerant electrons are spatially separated from the classical particles.

Journal Article↗