标题： 在超导电路中耗散激发四元组 显示英文标题

标题： Dissipating quartets of excitations in a superconducting circuit

摘要： 在过去十年中，玻色子量子位的自主稳定化已成为一种有前景的方法，用于硬件高效的量子信息保护。 然而，将这些技术应用于比薛定谔猫码更复杂的编码需要对高阶波混频过程进行精确控制。 挑战在于启用特定的多光子耗散通道，同时避免不需要的非线性相互作用。 在本工作中，我们利用由近似无Kerr效应的约瑟夫森元件实现的真实六波混频过程，在高阻抗超导谐振器中强制四重激发的耗散。 由于电路中残余的非线性来自杂散电感，这种耗散通道仅在谐振器包含特定数量的光子时才有效。 将其应用于谐振器的第四激发态，我们展示了状态衰减率的一个数量级的增强，而仅略微影响较低能态的弛豫和相干性。 考虑到通过电路设计的简单修改可以大幅减少杂散电感，并且我们的方法可以调整以激活更高阶的耗散通道，这些结果为四组分薛定谔猫量子位甚至更复杂的玻色子量子位的动力学稳定化铺平了道路。 显示英文摘要

摘要： Over the past decade, autonomous stabilization of bosonic qubits has emerged as a promising approach for hardware-efficient protection of quantum information. However, applying these techniques to more complex encodings than the Schr\"odinger cat code requires exquisite control of high-order wave mixing processes. The challenge is to enable specific multiphotonic dissipation channels while avoiding unintended non-linear interactions. In this work, we leverage a genuine six-wave mixing process enabled by a near Kerr-free Josephson element to enforce dissipation of quartets of excitations in a high-impedance superconducting resonator. Owing to residual non-linearities stemming from stray inductances in our circuit, this dissipation channel is only effective when the resonator holds a specific number of photons. Applying it to the fourth excited state of the resonator, we show an order of magnitude enhancement of the state decay rate while only marginally impacting the relaxation and coherence of lower energy states. Given that stray inductances could be strongly reduced through simple modifications in circuit design and that our methods can be adapted to activate even higher-order dissipation channels, these results pave the way toward the dynamical stabilization of four-component Schr\"odinger cat qubits and even more complex bosonic qubits.