Blind oracular quantum computation : from concept to physical implementation
Gustiani, Cica; DiVincenzo, David (Thesis advisor); Hassler, Fabian (Thesis advisor)
Aachen : RWTH Aachen University (2020, 2021)
Dissertation / PhD Thesis
Dissertation, RWTH Aachen University, 2020
Recent years have seen much excitement for application of quantum computing, triggered by substantial — and ongoing — advances in experimental realizations of quantum computing. It is widely believed that client-server is the setting for quantum computers that will prevail in the future, where privacy becomes crucial in the application. Moreover, a recent experiment by Barz et al.  successfully demonstrated a blind quantum computation scheme: a client-server quantum computation in which a client with limited quantum power controls the execution of a quantum computation on a powerful server, without revealing valuable details of the computation. In this thesis, we discuss the Blind Oracular Quantum Computation (BOQC) scheme, a blind quantum computing scheme in which a third party (the oracle)with limited quantum power, assists the execution of a client’s oracular quantum computations by implementing oracle evaluations. In BOQC, a client with limited quantum power and without the capacity to construct the oracle, can delegate her oracular quantum computations to a powerful yet untrustworthy server, with the help of the oracle. We show that BOQC is provably blind within a composable definition such that the server cannot learn about the clients’ computation. We provide a realization of BOQC in a physical setting, particularly in a diamond nitrogen-vacancy (NV) center platform. In BOQC, the server has a One-Way Quantum Computer (1WQC) that is resource-demanding. To lower the resource-requirements, we develop the BOQCo protocol, a BOQC that employs lazy 1WQC to minimize the number of qubits needed. We also provide systematic numerical optimization to find resource states that are BOQC-compatible by admitting BOQC security criteria. Finally, we give explicit oracular quantum algorithms that are BOQC-compatible to be executed on the NV-center platform. The algorithms include 2-qubit Grover’s algorithm using three qubits, 3-qubit exact Grover’s algorithm using four qubits, 2-qubit Simon’s algorithm with a useless oracle using four qubits, and Deutsch’s algorithm using three physical qubits. We hope that these BOQC algorithms intrigue some experimentalists to try to implement them. S. Barz et al. “Demonstration of Blind Quantum Computing”. In: Science 335.6066 (2012), pp. 303–308.