Quantum State Preparation with Optimal T-Count
Kewen Wu (Berkeley)
Monday, November 18th 2024, 2-3pm
Abstract:
How many T gates are needed to approximate an arbitrary n-qubit quantum state to within a given precision eps? Improving prior work of Low, Kliuchnikov, and Schaeffer, we show that the optimal asymptotic scaling is sqrt{2^n * log(1/eps)} + log(1/eps) if we allow ancilla qubits. We also show that this is the optimal T-count for implementing an arbitrary diagonal n-qubit unitary to within error eps. We describe applications in which a tensor product of many single-qubit unitaries can be synthesized in parallel for the price of one.