Developing Quantum Information Processors

量子力学给信息处理带来了基本的物理极限。通过建造量子计算机、量子通信系统、量子传感器和执行器，我们有效地达到了物理定律允许的功率和精度极限。量子信息处理(QIP)有望触及我们生活的几乎方方面面：我们与环境和彼此互动的方式，以及我们存储和处理知识的方式。实现这一转变所需的量子设备的开发才刚刚开始。今天，我们有了QIP的小型试验台。其中用途最广的仍然是基于自旋的处理器。我们建议将这些基于自旋的固态量子处理器进一步发展为量子传感器和执行器。这些将是导航和控制微观量子世界的工具。 我们正在探索的方法是量子系统的多节点混合。每个节点的核心是一个单电子自旋，作为一个执行器来设置、控制和测量存储在周围核自旋中的量子信息。这个致动器是一个相干的量子系统，所以组成本地处理器的物体可以与之相互作用，而不需要去相干。通过执行器，我们可以对处理器进行通用控制。最近的一项发现是，我们可以在节点之间形成量子通道。 QIP的这种方法的一个关键优势是，我们可以在并行操作中有效地从每个节点去除多余的熵(因此可以进行有效的纠错)。这些研究将是并行量子纠错(QEC)的第一个实验例子。然后，该测试台可用于确定在非平凡处理器中实现QEC的物理要求。 除了推进QIP的实施，这种新的光谱仪还将使分子薄膜的电子自旋共振研究成为一种新的化学研究能力。

Quantum mechanics poses the fundamental physical limits to information processing. By building quantum computers, quantum communication systems, and quantum sensors and actuators, we effectively reach the limits in power and accuracy allowed by the laws of physics. Quantum information processing (QIP) promises to touch nearly every aspect of our lives: the way we interact with the environment and each other and the way we store and process knowledge. The development of quantum devices necessary to achieve this transformation is just beginning. Today we have small test-beds for QIP. The most versatile of these remains the spin-based processors. We propose to further develop these solid-state, spin-based quantum processors into quantum sensors and actuators. These will be the tools for navigating and controlling the microscopic quantum world. The approach we are exploring is a multi-node hybrid of quantum systems. At the core of each node is a single electron spin that serves as an actuator to set, control and measure the quantum information stored in surrounding nuclear spins. This actuator is a coherent quantum system, so the objects that make up the local processor can interact with it without being decohered. Through the actuator we have universal control over the processor. A recent finding is that we can form a quantum channel between nodes. A key advantage of this approach to QIP is that we can efficiently remove excess entropy from each node in a parallel operation (so efficient error correction is possible). These studies will be the first experimental examples of parallel quantum error correction (QEC). This test-bed can then be used to determine the physical requirements for implementing QEC in a non-trivial processor. In addition to advancing implementations for QIP this new spectrometer will enable electron spin resonance studies of molecularly thin films: a new capacity for chemical studies.