Expanding the Interpolator Basis in the Variational Method to Explicitly Account for Backward Running States

Understand

In this paper, I show that backward (in time) running states can be explicitly accounted for by expanding the interpolator basis in the variational method in lattice QCD.

• The backward running states can then be removed by choosing an appropriate linear combination of interpolators, which improves the signal significantly.
• The proof of principle, which also makes use of the Time-Shift Trick (Generalized Pencil-of-Functions method), will be delivered at an example on a $64^4$ lattice close to the physical pion mass.