Readout and dynamics of a qubit built on three quantum dots

We present a model of a qubit built of three coherently coupled quantum dots with three spins in a triangular geometry. The qubit states are encoded in the doublet subspace and they are controlled by a gate voltage, which breaks the triangular symmetry of the system. We show how to prepare the qubit and to perform one-qubit operations. A doublet blockade effect in the current will be discussed. The blockade is related to an asymmetry of transfer rates from the electrodes to different doublet states and is used to read out the dynamics of the qubit state. Our research also presents analysis of the Rabi oscillations, decoherence, and leakage processes in the doublets subspace.