Observation of quantum jumps of a single quantum dot spin using sub-microsecond single-shot optical readout

摘要

Single-shot read-out of individual qubits is typically the slowest processamong the elementary single- and two-qubit operations required for quantuminformation processing. Here, we use resonance fluorescence from asingle-electron charged quantum dot to read-out the spin-qubit state in 800nanoseconds with a fidelity exceeding 80%. Observation of the spin evolution onlonger timescales reveals quantum jumps of the spin state: we use theexperimentally determined waiting-time distribution to characterize the quantumjumps. Embedding a quantum dot in a photonic nanostructure could be used toenhance the collection efficiency by a factor of 10, enabling single-shotread-out with a fidelity exceeding 97%.