Correlated quantum measurement of a solid-state qubit

Abstract

We propose a solid-state experiment to study the process of continuous quantum measurement of a qubit state. The experiment would verify that an individual qubit stays coherent during the process of measurement (in contrast to the gradual decoherence of the ensemble-averaged density matrix) thus confirming the possibility of the qubit purification by continuous measurement. The experiment can be realized using quantum dots, single-electron transistors, or SQUIDs.