CAPACITIVE COUPLING FOR FLUX QUBITS

目前基于通量量子比特的量子退火炉只具有电感耦合，导致ZZ相互作用(其中Z是计算基础)。对于未来的量子退火炉，要解决经典量子蒙特卡罗算法无法解决的问题，还需要不同的定性相互作用。其中一种相互作用是YY相互作用，它可以通过磁通量子比特的电荷自由度之间的电容耦合来实现。我们将设计、制造和表征一种基于单库珀对晶体管的磁通量子比特电压可调的非线性电容耦合器。

Current quantum annealers based on flux qubits feature only inductive coupling, resulting in a ZZ interaction (where Z is the computational basis). For future quantum annealers to solve problems which are out of the reach of the classical quantum Monte Carlo algorithm, qualitatively different interactions are additionally required. One such interaction is the YY interaction which can be implemented by capacitive coupling between the charge degree of freedom for flux qubits. We will design, fabricate and characterise a voltage-tuneable non-linear capacitive coupler for flux qubits based on the single Cooper-pair transistor.