2025/11/07 by Tsuji, Ryutaro, Hashimoto, Shoji, Kellermann, Ryan
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat)
paper · doi:10.48550/arxiv.2511.05058
Ground-state energy and matrix element are reconstructed from correlators in lattice QCD by diagonalizing transfer matrix T within the Krylov subspace spanned by Tn|χ⟩, where |χ⟩ is a state generated by an interpolating field on the lattice. In numerical applications, this strategy is spoiled by statistical noise. To circumvent the problem, we introduce a low-rank approximation based on a singular-value decomposition of a matrix made of the correlators. The associated bias is eliminated by an extrapolation to the limit of vanishing variance of energy eigenvalue. The strategy is tested using a set of mock data as well as real data of K and Ds meson correlators.