使用可調耦合器校準控制-Z閘以實現超過96%的保真度

Abstract

隨著單一量子位元量子邏輯閘的保真度已經趨於完美，針對兩個量子位元的操作與量子邏輯閘的保真度將成為下一個重要的議題。由於兩個量子位元間存在ZZ-交互作用，除了降低原本單一量子位元邏輯閘的保真度，也使兩個量子位元邏輯閘的操作受到限制。為了使兩個量子位元間的相互影響可以受到控制，量子耦合器成為不可或缺的角色。在這篇論文中我們首先要了解量子耦合器的性質，再來利用它建立且校準控制-Z閘，並藉由兩個量子位元的隨機標竿分析法來計算控制-Z閘的保真度。

As the fidelity of single-qubit quantum logic gates approaches perfection, the focus of quantum gate optimization has shifted to two-qubit operations. The fidelity of two-qubit gates has become a critical issue. Due to the presence of ZZ interactions between qubits, not only is the fidelity of single-qubit gates decreased, but the performance of two-qubit gates is also significantly limited. To mitigate and control the mutual interactions between qubits, quantum couplers have become an indispensable component. In this work, we first investigate the properties of tunable quantum couplers. We then utilize the coupler to construct and calibrate a Controlled-Z (CZ) gate, and evaluate its performance using two-qubit randomized benchmarking to determine the fidelity of the CZ gate.