arXiv:1603.05472 · Journal of Physics A Mathematical and Theoretical

Comonotonicity and Choquet integrals of Hermitian operators and their applications

Apostol Vourdas

Published Feb 22, 2016• 11 citations

Abstract

Abstract In a quantum system with d -dimensional Hilbert space, the Q -function of a Hermitian positive semidefinite operator θ , is defined in terms of the d 2 coherent states in this system. The Choquet integral of the Q -function of θ , is introduced using a ranking of the values of the Q -function, and Möbius transforms which remove the overlaps between coherent states. It is a figure of merit of the quantum properties of Hermitian operators, and it provides upper and lower bounds to various physical quantities in terms of the Q -function. Comonotonicity is an important concept in the formalism, which is used to formalize the vague concept of physically similar operators. Comonotonic operators are shown to be bounded, with respect to an order based on Choquet integrals. Applications of the formalism to the study of the ground state of a physical system, are discussed. Bounds for partition functions, are also derived.

DOI: 10.1088/1751-8113/49/14/145002

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