Analysis of current and shot noise correlations in a double quantum dot interferometer with interdot spin interactions

We examine an electron Aharonov-Bohm (AB) interferometer with individual quantum dots connected in parallel to macroscopic leads. Here, we focus on the effect that both interdot spin-spin exchange interactions and intradot spin flips have on the current- and frequency-dependent current shot noise. By appropriate control of AB magnetic flux, interdot Coulomb repulsion, intradot spin flips, and interdot spin-spin coupling, the probability amplitudes for the different paths of the interferometer can be controlled, leading to broad tunability of both the shape and the contrast of interference fringes in the current. We also show that in the shot noise at finite frequencies corresponding to the spin-spin interaction energies, the noise shows a pronounced super-Poissonian and sub-Poissonian structure. AB flux, which is not an integer multiple of 2π, dramatically suppresses the correlations in the shot noise.