Friday, January 21, 2011

The Kondo theory

Additional unwanted qubits in a phase qubit due to the Kondo effect.
Simmonds et.al. Phys. Rev. Lett 2005 
The Kondo effect is one of the interesting features of low temperatur physics where temperature is seen not to play as a smoother, instead it ruines the results taken from perturbation theory.   Last Monday I presented a talk titled "the Kondo effect" in a Colloquium at the Institute for Quantum Computing IQC in Waterloo.  It was a good opportunity to face with some interesting questions and comments...

In this talk I presented two exotic behavior of electron in low temperature, one in a quantum dot, and the second in the Josephson junction between two superconductors.  In a quantum dots I explained the Kondo plateaus predicted in 1988 by Glazman and Raikh in JETP Lett. and they observed by van der Wiel et.al. Science 2000. In the second half, I explained how this effect can causes the presence of additional unwanted qubits interacting with the computational qubit. And finally our recent idea of how to suppress them to prevent errors on computations...