In quantum computing, quantum information is lost due to a loss of synchronization (dephasing) in the electronic flow and energy relaxation. Magnetic flux noise is a dominant source of dephasing and energy relaxation in superconducting qubits. Out theoretical predictions pointed out oxygen and hydrogen as the causes of noise in these systems. These predictions were examined and confirmed by experiments that sew the reduction of magnetic noise for superconducting niobium and aluminum thin films after the surface treatment with ammonia. The identification of these adsorbates as sources explains the weak dependence of this type of noise on device materials. This new understanding of the origin of magnetic flux noise could lead to frequency-tunable superconducting qubits with improved dephasing times for practical quantum computers.
 

Prof. Wu obtained his PhD from Institute of Physics, Beijing in 1989 and did his postdoc research in Northwestern University, Evanston, during 1989-1994. He was professor of Physics in California State University, Northridge during 1994-2001, and has been professor of physics in University of California, Irvine, since 2001. He has published more than 260 papers and 10 book chapters.