Thursday, July 15, 2010

Justifying a common mantra

When one reads papers about quantum lattice models a key "dogma" that is often implicitly assumed is that a gap in the excitation spectrum (with particular
quantum numbers, e.g. triplets) is equivalent to short-range spatial correlations in some corresponding variable (e.g. spin-spin correlations).

Finding a rigorous justification for these kind a assertions is hard. However, a paper by Matthew Hastings does it under reasonably general conditions.

No comments:

Post a Comment

A very effective Hamiltonian in nuclear physics

Atomic nuclei are complex quantum many-body systems. Effective theories have helped provide a better understanding of them. The best-known a...