Physics – Condensed Matter – Superconductivity
Scientific paper
2006-08-17
Physics
Condensed Matter
Superconductivity
Scientific paper
We have investigated the fidelity and speed of single-shot current-pulse measurements of the three lowest energy states of the dc SQUID phase qubit. We apply a short (2ns) current pulse to one junction of a Nb/AlOx/Nb SQUID that is in the zero voltage state at 25 mK and measure if the system switches to the finite voltage state. By plotting the switching rate versus pulse size we can determine average occupancy of the levels down to 0.01%, quantify small levels of leakage, and find the optimum pulse condition for single-shot measurements. Our best error rate is 3% with a measurement fidelity of 94%. By monitoring the escape rate during the pulse, the pulse current in the junction can be found to better than 10 nA on a 0.1 ns time scale. Theoretical analysis of the system reveals switching curves that are in good agreement with the data, as well as predictions that the ultimate single-shot error rate for this technique can reach 0.4% and the fidelity 99.2%.
Anderson James R.
Cooper Ken B.
Dragt Alex J.
Dutta Sudeep K.
Lewis Myron R.
No associations
LandOfFree
Fast High-Fidelity Measurements of the Ground and Excited States of a dc-SQUID Phase Qubit does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fast High-Fidelity Measurements of the Ground and Excited States of a dc-SQUID Phase Qubit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fast High-Fidelity Measurements of the Ground and Excited States of a dc-SQUID Phase Qubit will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-388557