Universal spectral form factor for many-body localization

We theoretically study correlations present deep in the spectrum of many-body-localized systems. An exact analytical expression for spectral form factor Poisson spectra can be obtained and is shown to agree well with numerical results on two models exhibiting many-body-localization: a disordered quantum spin chain phenomenological $l$-bit model based existence local integrals motion. also identify universal regime that insensitive global density states as edge effects.