Probing Anderson Localization Using the Dynamics of a Qubit

Anderson localization refers to the absence of extended states in disordered lattice systems. One implication is exponential suppression of transmission. In this paper we study a two-level system coupled to an environment modelled by a semi-infinite chain via an N-site channel with and without disorder. We show that the decay of transmission affects the dynamics of a qubit coupled to the disordered system and we express the relaxation rate of the qubit in terms of the localization properties. As expected, adding static disorder to a channel coupled to a qubit will reduce the decoherence rate of the qubit compared to the channel without disorder. This could have practical applications: when designing electrodes that couple to qubits, it is possible to improve their performance by adding impurities to the channel.