Quantum-state reconstruction with imperfect rotations on an inhomogeneously broadened ensemble of qubits

Abstract

We present a method for performing quantum-state reconstruction on qubits and qubit registers in the presence of decoherence and inhomogeneous broadening. The method assumes only rudimentary single-qubit rotations as well as knowledge of decoherence and loss mechanisms. We show that full state reconstruction is possible even in the case where single-qubit rotations may only be performed imperfectly. Furthermore, we show that for ensemble quantum-computing proposals, quantum-state reconstruction is possible even if the ensemble experiences inhomogeneous broadening and if only imperfect qubit manipulations are available during state preparation and reconstruction.