2 problems

Consider the massless time-like regime of the XX chain and the complex correlation function $(-1)^m\langle\sigma^-_1(0)\sigma^+_{m+1}(t)\rangle$. Positivity conjecture. Both its re…

Let $r(m,t,h):=(-1)^m\langle \sigma^-_{1}(0)\sigma^+_{m+1}(t)\rangle_{-h,T}/I_m(t)$ be the ratio formed from the time-like correlation function and its leading asymptotic factor. F…