Abstract
We experimentally demonstrate fast and high-fidelity geometric control of a quantum system with the brachistochrone method on hybrid spin registers in diamond. Based on the time-optimal universal geometric control, single geometric gates with fidelities over $99.2%$ on the spin state of the nitrogen-vacancy center are realized with average durations shortened by $21.5%$ compared with the conventional geometric method. The fidelity of the fast geometric two-qubit gate exceeds $96.5%$ on the hybrid spin registers. With the fast and high-fidelity universal set of geometric gates available, we implement a quantum entanglement-enhanced phase estimation algorithm and demonstrate the Heisenberg quantum limit of phase estimation at room temperature. Hence our results show that high-fidelity quantum control based on a fast geometric route will be a versatile tool for broad applications of quantum information processing in practice.
Highlights
We demonstrate a single-loop brachistochrone nonadiabatic holonomic quantum computation (B-NHQC) in a prototype hybrid quantum system: a two-qubit register consisting of a nitrogen-vacancy (NV) electron and a 14N nuclear spin in diamond
Fast and high-fidelity quantum coherent control is of fundamental significance in quantum computation, simulation, and metrology
We have implemented robust BNHQC-based single- and two-qubit gates with hybrid spin registers in diamond, which paves the way for full fast geometric Quantum information processing (QIP) in practice
Summary
Quantum information processing (QIP), which can provide an unprecedented supremacy [1,2] over its classical counterpart in searching algorithms [3,4], simulations [5,6], metrology [7,8,9,10,11,12], and secure communication [13], relies seriously on high-quality quantum operations [14,15,16,17]. Based on adiabatic or nonadiabatic cyclical paths, it has been proposed as a promising method to realize high-fidelity and robust manipulation in theory [20,22,23,24,25,26], along with experimental demonstrations in various physical platforms, including superconducting circuits [27,28,29], nuclear magnetic resonance [30,31], and solid-state defects in diamond [32,33,34,35,36]. We demonstrate a single-loop brachistochrone nonadiabatic holonomic quantum computation (B-NHQC) in a prototype hybrid quantum system: a two-qubit register consisting of a nitrogen-vacancy (NV) electron and a 14N nuclear spin in diamond.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
