LETTER TO THE EDITOR: Diagonal approximation of the form factor of the unitary group
Abstract
The form factor of the unitary group U(N) endowed with the Haar measure characterizes the correlations within the spectrum of a typical unitary matrix. It can be decomposed into a sum over pairs of 'periodic orbits', where by periodic orbit we understand any sequence of matrix indices. From here the diagonal approximation can be defined in the usual fashion as a sum only over pairs of identical orbits. We prove that as we take the dimension N to infinity, the diagonal approximation becomes 'exact', that is converges to the full form factor in the interval τ ∈ [0, 1].
- Publication:
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Journal of Physics A Mathematical General
- Pub Date:
- January 2006
- DOI:
- 10.1088/0305-4470/39/4/L01
- arXiv:
- arXiv:nlin/0509037
- Bibcode:
- 2006JPhA...39L..77B
- Keywords:
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- Chaotic Dynamics
- E-Print:
- 9 pages