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QI: Fachverband Quanteninformation
QI 29: Quantum Information: Concept and Methods II
QI 29.3: Talk
Thursday, March 21, 2024, 15:30–15:45, HFT-TA 441
Time-optimal multi-qubit gates: Complexity, efficient heuristic and gate-time bounds — •Pascal Baßler1, Markus Heinrich1, and Martin Kliesch2 — 1Institute for Theoretical Physics, Heinrich Heine University Düsseldorf, Germany — 2Institute for Quantum Inspired and Quantum Optimization, Hamburg University of Technology, Germany
Multi-qubit entangling interactions arise naturally in several quantum computing platforms and promise advantages over traditional two-qubit gates. In particular, a fixed multi-qubit Ising-type interaction together with single-qubit X-gates can be used to synthesize global ZZ-gates (GZZ gates). We develop a method to synthesize such global ZZ-gate with optimal gate time. First, we show that the synthesis of such quantum gates that are time-optimal is NP-hard. Second, we develop a heuristic algorithm with polynomial runtime for synthesizing fast multi-qubit gates. Third, we derive lower and upper bounds on the optimal GZZ gate-time. Based on explicit constructions of GZZ gates and numerical studies, we conjecture that any GZZ gate can be executed in a time O(n) for n qubits. We expect that our efficient synthesis of fast multi-qubit gates allows for faster and, hence, also more error-robust execution of quantum algorithms.
Keywords: compiling; multi-qubit; time-optimal