This project demonstrates how the coherence time of an electron spin in a single quantum dot can be increased by 1000× by applying a pulse at an appropriate time such re-phasing (in the time ensemble) occurs. A T2 coherence time of ~3 microseconds is measured, which means that the “memory lifetime” of the qubit is about 105× longer than the time it takes to apply a single arbitrary axis rotation operation.
Figure 1. Fringe heights decay as a coarse delay between two \pi/2 pulses is increased, which is characteristic of a decoherence process. The fit of the decay yields the coherence time.
Dr. David Press
Kristiaan De Greve
Dr. Thaddeus Ladd
Prof. Yoshihisa Yamamoto