Qubit Metrology of Ultralow Phase Noise Using Randomized Benchmarking
PJJ O'Malley, J Kelly, R Barends, B Campbell, Y Chen, Z Chen, B Chiaro, A Dunsworth, AG Fowler, I-C Hoi, E Jeffrey, A Megrant, J Mutus, C Neill, C Quintana, P Roushan, D Sank, A Vainsencher, J Wenner, TC White Show all
Physical Review Applied | AMER PHYSICAL SOC | Published : 2015
A precise measurement of dephasing over a range of time scales is critical for improving quantum gates beyond the error correction threshold. We present a metrological tool based on randomized benchmarking capable of greatly increasing the precision of Ramsey and spin-echo sequences by the repeated but incoherent addition of phase noise. We find our superconducting-quantum-interference-device-based qubit is not limited by 1/f flux noise at short time scales but instead observe a telegraph noise mechanism that is not amenable to study with standard measurement techniques.
Awarded by Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) through the Army Research Office
We thank A. Veitia for helpful discussions on the theory of noise and RB. This work is supported by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) through the Army Research Office Grants No. W911NF-09-1-0375 and No. W911NF-10-1-0334. All statements of fact, opinion, or conclusions contained herein are those of the authors and should not be construed as representing the official views or policies of IARPA, the ODNI, or the U.S. government. Devices are made at the UC Santa Barbara Nanofabrication Facility, a part of the NSF-funded National Nanotechnology Infrastructure Network, and at the NanoStructures Cleanroom Facility.