标题： 作为条件双光子门中介的工程化超导分子 显示英文标题

标题： Engineering giant transmon molecules as mediators of conditional two-photon gates

摘要： 人工原子非局部耦合到波导——所谓的巨原子——为控制光和物质提供了新的机会。 在本工作中，我们展示如何使用一组非局部耦合的transmon“分子”来设计一个被动光子受控门用于波导光子。 特别是，我们展示了由于方向依赖性耦合之间的相互作用，通过非局部相互作用和分子结合强度的相互作用而设计的；以及transmon阵列的非线性，导致反向传播光子之间的条件弹性相位移。 我们分析了获得最大$\pi$-相位移——从而得到CZ门的条件，并将门保真度作为关键实验参数的函数进行表征，包括有限的transmon非线性、发射器光谱不均匀性和有限的协作度。 我们的工作开启了巨原子作为微波光子量子计算设备关键元件的应用。 显示英文摘要

摘要： Artificial atoms non-locally coupled to waveguides -- the so-called giant atoms -- offer new opportunities for the control of light and matter. In this work, we show how to use an array of non-locally coupled transmon "molecules" to engineer a passive photonic controlled gate for waveguide photons. In particular, we show that a conditional elastic phase shift between counter-propagating photons arises from the interplay between direction-dependent couplings, engineered through an interplay of non local interactions and molecular binding strength; and the nonlinearity of the transmon array. We analyze the conditions under which a maximal $\pi$-phase shift -- and hence a CZ gate -- is obtained, and characterize the gate fidelity as a function of key experimental parameters, including finite transmon nonlinearities, emitter spectral inhomogeneities, and limited cooperativity. Our work opens the use of giant atoms as key elements of microwave photonic quantum computing devices.