Superconducting Qubits Are Getting Serious

December 12, 2011 (HP44).  We would like to attract the attention of our readers interested in quantum computing to the paper by Hanhee Paik et al, a team from Yale University, Univ. of Chicago, University of Maryland and Raytheon BBN Technologies, which appeared this week in Phys. Rev. Lett. 107, 240501 (2011) .  The authors observed high coherence and stability (T₁ up to 60 msec, T₂ up to 20 msec without spin echo) of Josephson junction qubits measured in a three-dimensional resonant cavity, with no evidence for 1/f critical current noise.  The reported results suggest that the overall quality of Josephson junctions in these qubits will allow error rates of a few 10-4, approaching already the error correction threshold.

The significance of this work for quantum computing is explained in the Viewpoint by Matthias Steffens (IBM Research Center, Yorktown Heights) which appeared in Physics 4, 103 – published on December 5, 2011 (DOI: 10:1103/Physics.4.103).