The Spectral Structure of Correlator Matrices

Understand

In lattice QCD spectrum calculations, it is desirable to obtain multiple excited state energies in each symmetry channel.

• Typically, one constructs several interpolating operators for the symmetry channel of interest, forms the `correlator matrix' of all possible two-point functions, and uses the variational method to obtain as many energy levels as possible.
• We present a detailed look at this last step, starting from a discussion of the symmetry properties and spectral structure of the correlator matrix.
• We continue by motivating and describing the variational method, before discussing some conceptual and practical challenges concerning the light baryon sector.