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arXiv · 2305.05491

Feynman--Hellmann approach to transition matrix elements and quasi-degenerate energy states

M. Batelaan·K. U. Can·R. Horsley·Y. Nakamura·P. E. L. Rakow·G. Schierholz·H. Stüben·R. D. Young·J. M. Zanotti
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Abstract

The Feynman--Hellmann approach to computing matrix elements in lattice QCD by first adding a perturbing operator to the action is described using the transition matrix and the Dyson expansion formalism. This perturbs the energies in the two-point baryon correlation function, from which the matrix element can be obtained. In particular at leading order in the perturbation we need to diagonalise a matrix of near-degenerate energies. While the method is general for all hadrons, we apply it here to a study of a Sigma to Nucleon baryon transition vector matrix element.

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M. Batelaan, K. U. Can, R. Horsley, Y. Nakamura, P. E. L. Rakow, G. Schierholz, H. Stüben, R. D. Young, J. M. Zanotti. 2023-05-09. Feynman--Hellmann approach to transition matrix elements and quasi-degenerate energy states. https://doi.org/10.1103/physrevd.108.034507

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