Based on single trapped cesium atoms in a micro-FORT, we have demonstrated quantum state initialization, detection and manipulation of the corresponding qubit encoded in the “clock state” with high efficiencies. The decoherence times are measured by Ramsey spectroscopy and spin-echo method. The measured decoherence time is much longer than the operation time of single qubit gate and it could be further improved by increasing the single qubit transition efficiency and scale the single qubit to more. Such robust single qubit system implies a powerful competitor for quantum information processing.

Rabi flopping of single atomic qubit. The round points with error bars are experimental data. Each data point is obtained by the statistic over more than 80 samples and the range of error bars shown here is ±σ. The red curve are the corresponding sine wave fitting, which gives a single qubit Rabi rotation rate of 2π × (229.0 ± 0.6) kHz.

The evolution of Ramsey fringe amplitude on time delay between two π/2 pulses. The round points with error bars are experimental data. Each point is obtained by the statistic over more than 80 samples and the range of error bars shown here is ±σ. The red curve is the corresponding exponential fitting, which gives a single qubit coherence time of 3.0 ± 0.7 ms. The inset shows the Ramsey fringe around time delay T = 0.5 ms.