Exotic Circuits for Enhanced Quantum Algorithms and Computation

Abstract

Quantum circuits play an essential role in many disciplines of quantum information science. They can not only be represented in the traditional gate-based paradigm, but also an alternative measurement-based paradigm. The latter begins from a resource state possessing many entangled ancillary qubits, and proceeds via mid-circuit measurements of these ancillas. More generally, ancillary qubits feature prominently in quantum error-correcting schemes, opening up the possibility for exploiting both paradigms on an equal footing. In this thesis, we explore how circuits designed with such features (referred to as “exotic”) can be employed to enhance the quality of variational quantum eigensolver (VQE) algorithms and general quantum computations via noise mitigation. By applying these exotic circuits in resource-efficient and versatile ways, we can pave the way for more reliable computations on current noisy-intermediate-scale-quantum (NISQ) devices.