Demonstration of sympathetic cooling and diabatic ion transport in an ion trap quantum computer

微芯片X结离子陷阱阵列上的离子传输是在囚禁离子量子计算机上实现量子算法的关键组成部分(图1(A))。在苏塞克斯，我们最近实现了新一代离子芯片，它包括一个X结离子陷阱阵列以及实现高保真2量子位门所需的集成载流线(图1(B)、图1(C))。我们已经演示了通过X结离子陷阱阵列的传输，以及其他相关的穿梭操作。为了执行量子算法，我们需要利用非绝热穿梭的思想来演示快速的离子传输操作。我们正在开发非绝热穿梭技术，这是我们与伦敦帝国理工学院弗洛里安·明特团队合作的一部分。与绝热离子传输不同，在绝热离子传输中，离子保留在穿梭势井的底部，非绝热离子传输利用对捕获势的相敏控制，以便在不向离子注入动能的情况下实现快速传输。交感冷却是离子陷阱量子计算机的一个关键特征，因为它允许冷却保存量子信息的离子，而不会扰乱用于保存量子信息的离子的内态。连接交感冷却和快速非绝热离子传输是构建实用量子计算机的关键因素。作为这项学习的一部分，学生将展示出对钡离子的共鸣降温。然后，学生将介绍一套离子传输方案，在这些方案中，他们将演示非绝热穿梭，然后是交感冷却。我们将研究最优方案，并评估在非绝热输运之前分离量子离子和冷却离子还是进行混合物种非绝热离子输运是最好的。该项目将最终执行一种量子算法，包括门执行、非绝热穿梭和共鸣冷却。

Ion transport on microchip X-junction ion trap array is a key ingredient to for the implementation of quantum algorithms on a trapped ion quantum computer (Fig. 1(a)). At Sussex we have recently realized a new generation of ion chips which incorporate an X-junction ion trap array as well as integrated current carrying wires required to implement high-fidelity 2-qubit gates (Fig. 1(b), Fig. 1(c)). We have already demonstrated transport through an X-junction ion trap array, along with other relevant shuttling operations. In order to execute quantum algorithm, we need to demonstrate fast ion transport operations making use of the idea of diabatic shuttling. We are developing diabatic shuttling as part of a collaboration with Florian Mintert's group at Imperial College London. In contrast to adiabatic ion transport where the ion remains of the bottom of the well of the shuttling potential, diabatic ion transport makes use of phase sensitive control of the trapping potentials in order to allow for fast transport without injecting kinetic energy to the ion. Sympathetic cooling is a key feature of an ion trap quantum computer as it allows to cool the ion holding quantum information without scrambling its internal state that is used to hold quantum information. Connecting sympathetic cooling and fast diabatic ion transport is a key ingredient in building a practical quantum computer. As part of this studentship, the student will demonstrate sympathetic cooling with Barium ions. The student will then introduce a set of ion transport protocols where they will demonstrate diabatic shuttling followed by sympathetic cooling. We will investigate optimal protocols and evaluate whether it is best to separate the quantum ion and the cooling ion before diabatic transport or carry out mixed species diabatic ion transport. The project will culminate in the execution of a quantum algorithm including gate execution, diabatic shuttling and sympathetic cooling.