Abstract
A flux qubit biased at its symmetry point shows a minimum in the energy splitting (the gap), providing protection against flux noise. We have fabricated a qubit of which the gap can be tuned fast and have coupled this qubit strongly to an oscillator. We show full spectroscopy of the qubit-oscillator system and generate vacuum Rabi oscillations. When the gap is made equal to the oscillator frequency we find the largest vacuum Rabi splitting of . Here being at resonance coincides with the optimal coherence of the symmetry point.
- Received 9 April 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.060503
© 2010 The American Physical Society