Central extensions of the Heisenberg algebra
arXiv:0810.3365
Abstract
We study the non-trivial central extensions of the Heisenberg algebra recently constructed in {AccBouCE}. We prove that a real form of is one the fifteen classified real four--dimensional solvable Lie algebras. We also show that can be realized (i) as a sub--Lie--algebra of the Schroedinger algebra and (ii) in terms of two independent copies of the canonical commutation relations (CCR). This gives a natural family of unitary representations of and allows an explicit determination of the associated group by exponentiation. In contrast with , the group law for is given by nonlinear (quadratic) functions of the coordinates.