Harnessing supercomputers to correct quantum errors

A quantum computer is composed of a relatively large number of “qubits” and it is inherently a many-body quantum system. An actual implementation of a quantum computer will have to deal with two fundamentally different sources of noise i.e. classical and quantum noise. Classical noise is due to electric or magnetic fields fluctuations and/or the presence of charges in the apparatus. Quantum noise is due to system impurities like nuclear spins or defects. It is thus appropriate to describe a quantum computer as a many-body open quantum system, where the term “open” signifies that the system interacts with some environment.

The occurrence of errors in quantum computations or in the storage of quantum data, has been studied for many years, and several key strategies devised are quantum error corrections or dynamical decoupling. A team of researchers at Singapore University of Technology and Design, led by A/Prof Dario Poletti, and A/Prof Ng Hui Khoon and her group at Yale-NUS and the Centre for Quantum Technologies, NUS, are tapping onto NSCC’s supercomputing resources to tackle the study of quantum error correction and dynamical decoupling for a quantum computer under the effects of quantum and classical noise, i.e. studied as a many-body open quantum system.

The aim of the research is to produce improved models for the environment and the resulting noise on the quantum computing system. With such models, one can better understand how well quantum error correction and fault-tolerant schemes can deal with the adverse effects of noise on the state of the quantum computer.