QSI Seminar: Romy Minko (University of Bristol)
In this QSI Seminar on Wed 18 Oct 2023, Dr Romy Minko will outline the novel procedure for approximating general single-qubit unitaries from a finite universal gate set. Image: AdobeStock.
Shorter quantum circuits via single-qubit gate approximation
SPEAKER: Dr Romy Minko
AFFILIATION: University of Bristol
ABSTRACT: We give a novel procedure for approximating general single-qubit unitaries from a finite universal gate set by reducing the problem to a novel magnitude approximation problem, achieving an immediate improvement in sequence length by a factor of 7/9. Extending the works arXiv:1612.01011 and arXiv:1612.02689, we show that taking probabilistic mixtures of channels to solve fallback (arXiv:1409.3552) and magnitude approximation problem saves factor of two in approximation costs. In particular, over the Clifford+sqrt(T) set we achieve an average non-Clifford gate count of 0.23 log_2(1/epsilon)+2.13 and T-count 0.56log_2(1/epsilon) + 5.3 with mixed fallback approximations for diamond norm accuracy epsilon. We look at a family of gate sets known as quaternion gate sets, with particular emphasis on numerical results for Clifford+T and Clifford+sqrt(T) gate sets.
The work represents a collaboration between Dr Romy Minko (University of Bristol; Oxford University), Vadym Kliuchnikov (Microsoft Quantum), Dr Kristin Lauter (Facebook AI), Adam Paetznick (Microsoft Quantum) and Christophe Petit (University of Birmingham; Universit´e Libre de Bruxelles).
HOSTED BY: Dr Ryan Mann, Centre for Quantum Software and Information, University of Technology Sydney, Australia
