An exact relation between free energy fluctuations and bond chaos in the Sherrington-Kirkpatrick model

Using a variant of the interpolating Hamiltonian technique, we show that there exists, in the Sherrington-Kirkpatrick spin glass, an exact connection between the sample-to-sample fluctuations of the free energy and bond chaos involving 2- and 4-replica overlaps between replicas with different but correlated bonds. This relation is used to derive an upper bound of the fluctuations.