Form factor for a family of quantum graphs: an expansion to third order

Autor: Gregory Berkolaiko, Robert S. Whitney, Holger Schanz
Rok vydání: 2003
Předmět:
Zdroj: Journal of Physics A: Mathematical and General. 36:8373-8392
ISSN: 1361-6447
0305-4470
DOI: 10.1088/0305-4470/36/31/303
Popis: For certain types of quantum graphs we show that the random-matrix form factor can be recovered to at least third order in the scaled time $\tau$ from periodic-orbit theory. We consider the contributions from pairs of periodic orbits represented by diagrams with up to two self-intersections connected by up to four arcs and explain why all other diagrams are expected to give higher-order corrections only. For a large family of graphs with ergodic classical dynamics the diagrams that exist in the absence of time-reversal symmetry sum to zero. The mechanism for this cancellation is rather general which suggests that it may also apply at higher-orders in the expansion. This expectation is in full agreement with the fact that in this case the linear-$\tau$ contribution, the diagonal approximation, already reproduces the random-matrix form factor for $\tau
Comment: 23 pages (including 4 fig.) - numerous typos corrected
Databáze: OpenAIRE