Robust gate for quantum computation

Project title: Robust gate for quantum computation
Main applicant: Erik Sjöqvist, Division of Materials Theory
Grant amount: 3 100 000 SEK for the period 2017-2021
Funder: Project grant from the Swedish Research Council

Project description

Quantum computation is a form of information processing that promises efficient solution of certain computationally demanding problems and will play an important role in simulation of complex quantum systems. A key challenge in realizing large-scale quantum computers is to handle different types of errors, such as parameter noise, decoherence, and transitions to states outside the computational state space. In this four-year project, we develop new strategies that overcome a wide range of error types to pave the way for the realization of robust quantum gates and thereby take a significant step towards the realization of useful quantum computers. The strategies have in common the use of quantum holonomies, i.e., non-Abelian geometric phases, which are resilient to instabilities in experimental control parameters. To broaden the range of addressable error types, we combine the holonomic approach with other error resilient methods, such as optimization of sequences and shapes of control pulses, refocusing, adiabatic shortcut to implement high-speed simulation of adiabatic control, and optimal quantum control theory to handle quantum information processing in real multilevel systems. The project involves an extensive collaboration with Prof. Stefan Kröll, Lund University, on experimental implementation of the optimization strategies for qubits in rare-earth-ion-doped crystals.