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

微芯片x结离子阱阵列上的离子输运是在捕获离子量子计算机上实现量子算法的关键因素（图1(a)）。在苏塞克斯，我们最近实现了新一代离子芯片，其中包括x结离子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离子传输操作。作为与伦敦帝国理工学院弗洛里安·明特团队合作的一部分，我们正在开发绝热穿梭。与绝热离子输运相反，在绝热离子输运中，离子保持在穿梭势阱的底部，绝热离子输运利用捕获势的相敏控制，以便在不向离子注入动能的情况下实现快速输运。共感冷却是离子阱量子计算机的一个关键特征，因为它可以在不扰乱用于保存量子信息的内部状态的情况下冷却保存量子信息的离子。连接交感冷却和快速绝热离子传输是构建实用量子计算机的关键因素。作为这项研究的一部分，学生将演示用钡离子进行交感冷却。然后，学生将介绍一套离子传输协议，在那里他们将演示在交感冷却之后的绝热穿梭。我们将研究最佳方案，并评估在非绝热输运之前将量子离子和冷却离子分离或进行混合种非绝热离子输运是最好的。该项目最终将执行一个量子算法，包括门执行、绝热穿梭和同情冷却。

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.