Fig. 4: One- and two-axis dynamical decoupling.
From: Universal quantum control of an atomic spin qubit on a surface
a Pulse sequences of CP (upper) and CPMG (lower) with four refocusing pulses. X and Y pulses are labeled in red and green, respectively. b Signals measured with the three CP (N = 1, 2, and 4) and one CPMG (N = 4) sequences. (VDC = 50 mV, IDC = 4 pA, VRF = 120 mV). Solid curves are exponential fits, where the red (green) color stands for CP (CPMG) sequence. c Coherence time \({T}_{2}\) extracted from the data in b. Note that measurements with larger N yield significantly longer \({T}_{2}\), whereas CP-4 and CPMG-4 result in similar coherence times of 277 ± 20 and 292 ± 23 ns, respectively. Error bars denote the 95% confidence intervals of the exponential fits. Duration of the \({\rm{\pi }}/2\) pulses is ~13 ns.
