Ancilla-driven quantum computation for qudits and continuous variables

Journal Article · Wed May 10 00:00:00 EDT 2017 · Physical Review A

DOI:https://doi.org/10.1103/physreva.95.052317· OSTI ID:1411880

Proctor, Timothy ^[1]; Giulian, Melissa ^[2]; Korolkova, Natalia ^[2]; Andersson, Erika ^[3]; Kendon, Viv ^[4]

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1. Univ. of Leeds, Leeds (United Kingdom); Univ. of California, Berkeley, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2. Univ. of St. Andrews, Fife (Scotland)
3. Heriot-Watt Univ., Edinburgh (United Kingdom)
4. Durham Univ., Durham (United Kingdom)

Although qubits are the leading candidate for the basic elements in a quantum computer, there are also a range of reasons to consider using higher-dimensional qudits or quantum continuous variables (QCVs). In this paper, we use a general “quantum variable” formalism to propose a method of quantum computation in which ancillas are used to mediate gates on a well-isolated “quantum memory” register and which may be applied to the setting of qubits, qudits (for d>2), or QCVs. More specifically, we present a model in which universal quantum computation may be implemented on a register using only repeated applications of a single fixed two-body ancilla-register interaction gate, ancillas prepared in a single state, and local measurements of these ancillas. In order to maintain determinism in the computation, adaptive measurements via a classical feed forward of measurement outcomes are used, with the method similar to that in measurement-based quantum computation (MBQC). We show that our model has the same hybrid quantum-classical processing advantages as MBQC, including the power to implement any Clifford circuit in essentially one layer of quantum computation. In some physical settings, high-quality measurements of the ancillas may be highly challenging or not possible, and hence we also present a globally unitary model which replaces the need for measurements of the ancillas with the requirement for ancillas to be prepared in states from a fixed orthonormal basis. In conclusion, we discuss settings in which these models may be of practical interest.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1411880
• Report Number(s): SAND--2017-6076J; 656114
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 5 Vol. 95; ISSN PLRAAN; ISSN 2469-9926
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING