2005/01/25 by Tatsuya Kutsuzawa, Shiro Saito, Hirotaka Tanaka +3
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1063/1.2010610
published as Appl. Phys. Lett. 87, 073501 (2005) (3 pages) · 3 pages, 3 figures
arxiv created 2005/01/25 · arxiv updated 2009/12/01
The quantum state of a flux qubit was successfully pulse-controlled by using a resonant microwave. We observed Ramsey fringes by applying a pair of phase-shifted pi/2 microwave pulses without introducing detuning. With this method, the qubit state can be rotated on an arbitrary axis in the x-y plane of the Bloch sphere in a rotating frame. We obtained a qubit signal from a coherent oscillation with an angular velocity of up to 2pi*11.4 Grad/s. In combination with Rabi pulses, this method enables us to achieve full control of single qubit operation. It also offers the possibility of orders of magnitude increases in the speed of the arbitrary unitary gate operation.