Fidelity of single qubit gates

Start date 01/01/2008
The above picture shows the system which is used to read out and control the state of the qubit. The qubit, depicted as an arrow on the so called Bloch sphere, a common representation of a quantum two-level system, is coupled to microwave photons in a cavity made from a co-planar wave guide. By controlling the phase and amplitude of the photons, the state of the qubit can be manipulated to reach all parts on the Bloch sphere. The graph below shows the error-probability as a function of the time it takes to perform the gate operation.
 
One of the basic requirements for quantum information processing and communication is the ability to perform high fidelity operations on the quantum state of the qubit. In this work we present measurements of the errors in single qubit gates for a superconducting qubit using three different metrics for the gate fidelity. Consistently, we obtain low gate errors ~ 1-2% across all metrics. Comparison with theoretical simulations show that the limits on gate fidelity are primarily imposed by qubit decoherence, that is intrinsic sources of error.

The picture shows the system which is used to read out and control the state of the qubit. The qubit, depicted as an arrow on the so called Bloch sphere, a common representation of a quantum two-level system, is coupled to microwave photons in a cavity made from a co-planar wave guide. By controlling the phase and amplitude of the photons, the state of the qubit can be manipulated to reach all parts on the Bloch sphere. The graph below shows the error-probability as a function of the time it takes to perform the gate operation.

The work is done together with Yale University.




Swedish Research Council (VR)

Published: Thu 09 Feb 2017.