Measurement-based entanglement of spin qubits

量子信息的基本单位是量子比特或量子位。与经典比特一样，量子比特是一个两级系统，但具有以叠加状态存在的能力。这意味着它可以同时处于开和关状态，如果我们考虑超过一个量子位的量子系统，这将产生深远的影响。每个量子位不是携带任何定义良好的信息，而是将信息编码在它们的联合属性中。在量子力学中，量子比特被描述为纠缠态。挑战在于找到利用叠加和纠缠等量子现象的方法来构建量子计算机，使其能够执行在经典环境中无法实现的计算任务。该项目将通过使用一种创新的基于测量的量子计算方法来解决这个问题，该方法利用了一种有趣的量子力学效应，即如果测量无法将两个空间分离的量子比特分开，它们就会纠缠在一起。计算是通过对消耗纠缠的单个量子位进行一系列测量来实现的，这种方法与标准的基于电路的量子计算完全不同。最终目标是展示一个全电子和可扩展的分布式量子处理器，它不需要量子比特之间的任何直接交互。具体来说，该项目利用固态电子自旋量子比特（量子点或掺杂剂）产生纠缠，超精细相互作用，以长寿命的核自旋状态存储量子信息，以及超快射频反射读数。

The elementary unit of quantum information is the quantum bit or qubit. Like the classical bit, the qubit is a two-level system but with the ability to exist in a superposition of states. This means it can be in the on and off state at the same time which has profound implications if we consider quantum systems of more than one qubit. Instead of each qubit carrying any well-defined information of its own, the information is encoded in their joint properties. In quantum mechanics, the qubits are described as being entangled. The challenge is to find ways to harness quantum phenomena such as superposition and entanglement to construct a quantum computer that is able to perform computational tasks that are unattainable in a classical context.This project will address this by using an innovative measurement-based approach to quantum computation which makes use of an intriguing quantum mechanical effect by which two spatially separated quantum bits become entangled if a measurement cannot tell them apart. Computation is then achieved by a sequence of measurements on individual qubits that consumes the entanglement - an approach which is entirely different from standard circuit-based quantum computation. The end goal is to demonstrate an all-electrical and scalable distributed quantum processor that does not require any direct interaction between the qubits. Specifically, the project makes use of solid-state electron spin qubits (quantum dots or dopants) to generate entanglement, hyperfine interaction to store quantum information in long-lived nuclear spin states and ultrafast radio-frequency reflectometry readout.