February 2014
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Day February 6, 2014

Pseudospectra in non-Hermitian quantum mechanics

D. Krejcirik, P. Siegl, M. Tater, J. Viola

We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis properties of eigenfunctions. The abstract results are illustrated by unexpected wild properties of operators familiar from PT-symmetric quantum mechanics.


Spectral Theory (math.SP); Mathematical Physics (math-ph); Quantum Physics (quant-ph)

Some invariant biorthogonal sets with an application to coherent states

F. Bagarello, S. Triolo

We show how to construct, out of a certain basis invariant under the action of one or more unitary operators, a second biorthogonal set with similar properties. In particular, we discuss conditions for this new set to be also a basis of the Hilbert space, and we apply the procedure to coherent states. We conclude the paper considering a simple application of our construction to pseudo-hermitian quantum mechanics.

Mathematical Physics (math-ph)