Higher-dimensional ancilla-driven quantum computation
Timothy J Proctor, Viv M. Kendon · arXiv (Cornell University) · 2015
A model of universal quantum computation with qudits ($d$-level systems) is presented in which the gates are implemented on a register entirely via fixed-form sequential interactions with ancillary qudits followed by adaptive, variable basis measurements of these ancillas. The model maintains determinism via classical feed-forward of measurement outcomes in a similar fashion to the qudit one-way model. An embedding of the qudit one-way model is given which demonstrates that the hybrid quantum-classical advantages of one-way quantum computation are also inherent in the model presented here, including the ability to implement any Clifford gate in constant depth using multiple ancillas in parallel. A model which requires only fixed basis measurements is then presented, but due to the lack of adaptive controls it can only implement universal quantum computation in a stochastic sense. Interestingly, this scheme may then be altered to recover determinism by replacing ancilla measurements with ancilla preparation. These models provide an intuitive setting for understanding the interplay between the benefits gained from classical controls, measurements and state preparation in the context of multi-valued logic ancilla-based quantum computation.