论文标题
在深层地下设施中运行可改善甜蜜景点的渐进式升华量子的锁定
Operating in a deep underground facility improves the locking of gradiometric fluxonium qubits at the sweet spots
论文作者
论文摘要
我们使用两个对称的颗粒铝（GRAL）环以实现超级对电位的方式，展示了渐变磁力升级的人工原子的通量偏置锁定和操作。渐变磁通显示对均匀磁场的敏感性的两个数量级抑制，这可能是需要强磁场偏置的混合量子系统的资产。通过在越过金属到刺激器过渡的同时在外部磁场中冷却设备，可以分别以$ 0 $或$φ_0/2 $有效的磁通偏置为层次计量法磁通量，分别对应于偶数或奇数的捕获磁通量。在MK温度下，初始化期间制备的Fluxon均等均可生存到超过$ 100 \，φ_0$的磁场偏差。但是，即使对于在$ 1 \，φ_0$附近偏见的状态，我们也观察到了几个小时的短速度寿命，这无法通过热或量子相滑。当在Gran Sasso实验室的深层低温恒温器中运行时，Fluxon的寿命会增加到几天，这表明电离事件激活了Gral超级电阻器中的相位滑动。
We demonstrate flux-bias locking and operation of a gradiometric fluxonium artificial atom using two symmetric granular aluminum (grAl) loops to implement the superinductor. The gradiometric fluxonium shows two orders of magnitude suppression of sensitivity to homogeneous magnetic fields, which can be an asset for hybrid quantum systems requiring strong magnetic field biasing. By cooling down the device in an external magnetic field while crossing the metal-to-superconductor transition, the gradiometric fluxonium can be locked either at $0$ or $Φ_0/2$ effective flux bias, corresponding to an even or odd number of trapped fluxons, respectively. At mK temperatures, the fluxon parity prepared during initialization survives to magnetic field bias exceeding $100 \,Φ_0$. However, even for states biased in the vicinity of $1 \,Φ_0$, we observe unexpectedly short fluxon lifetimes of a few hours, which cannot be explained by thermal or quantum phase slips. When operating in a deep-underground cryostat of the Gran Sasso laboratory, the fluxon lifetimes increase to days, indicating that ionizing events activate phase slips in the grAl superinductor.
