Accession Number : AD1004442


Title :   Accurate Control of Josephson Phase Qubits


Descriptive Note : Journal Article


Corporate Author : Massachusetts Institute of Technology Cambridge United States


Personal Author(s) : Steffen,Matthias ; Martinis,John M ; Chuang,Isaac L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1004442.pdf


Report Date : 14 Apr 2016


Pagination or Media Count : 9


Abstract : A quantum bit is a closed two-dimensional Hilbert space, but often experimental systems have three or more energy levels. In a Josephson phase qubit the energy differences between successive levels differ by only a few percent, and hence care must be taken to isolate the two desired levels from the remaining Hilbert space. Here we show via numerical simulations how to restrict operations to the qubit subspace of a three-level Josephson junction system requiring shorter time duration and suffering less error compared with traditional methods. This is achieved by employing amplitude modulated pulses as well as carefully designed sequences of square wave pulses. We also show that tunneling out of higher lying energy levels represents a significant source of decoherence that can be reduced by tuning the system to contain four or more energy levels.


Descriptors :   Hilbert space , coherence , JOSEPHSON JUNCTIONS , QUANTUM COMPUTING


Distribution Statement : APPROVED FOR PUBLIC RELEASE