Theory of strong driving of silicon quantum dot qubits

Who: Yuan-Chi Yang, University of Wisconsin-Madison
When: 
Friday, August 31, 2018 - 12:00pm
Where: 
103 Allen Hall

Quantum computation is a promising way to expand computational power as well as perform quantum simulations. There are many proposals on implementing quantum computation, including topological materials, trapped ions, superconducting circuits as well as semiconductor quantum dots. Semiconductor quantum dot qubits are promising candidates for quantum information processing and have recently made substantial experimental progress. One challenge for qubits without topological protection, however, is to suppress decoherence. Performing qubit gate operations as quickly as possible can be important to minimize the effects of decoherence. For resonant gates, this requires applying a strong ac drive. However, strong driving can present control challenges because of the strong driving effects that cannot be described using the rotating-wave approximation. Here we analyze resonant X rotations of a silicon double quantum dot hybrid qubit within a dressed-state formalism. We show that the strong driving effects can be suppressed to the point that gate fidelities above 99.99% are possible, in the absence of decoherence. When coupled to 1/f charge noise typical to our device, we further show that, by applying strong driving, gate fidelities can be above 99.9%. This shows that the quantum operations on silicon quantum dot hybrid qubits can be above the error-correction threshold, which is an important step towards realizing quantum computation.