Symmetry Integrability and Geometry Methods and Applications
SU 2 Nonstandard Bases: Case of Mutually Unbiased Bases
Olivier Albouy
Abstract
This paper deals with bases in a finite-dimensional Hilbert space.Such a space can be realized as a subspace of the representation space of SU 2 corresponding to an irreducible representation of SU 2 .The representation theory of SU 2 is reconsidered via the use of two truncated deformed oscillators.This leads to replacement of the familiar scheme {j 2 , j z } by a scheme {j 2 , v ra }, where the two-parameter operator v ra is defined in the universal enveloping algebra of the Lie algebra su 2 .The eigenvectors of the commuting set of operators {j 2 , v ra } are adapted to a tower of chains SO 3 ⊃ C 2j+1 (2j ∈ N * ), where C 2j+1 is the cyclic group of order 2j + 1.In the case where 2j + 1 is prime, the corresponding eigenvectors generate a complete set of mutually unbiased bases.Some useful relations on generalized quadratic Gauss sums are exposed in three appendices.