CAREER: Taming Entanglement in Open Quantum Systems

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。纠缠是量子力学的基本特征，它允许量子处理器比经典处理器更快地处理特定任务。创造和保护纠缠的主要挑战是退相干：一个被环境“测量”的量子系统失去了它的量子相关性，并被投射到经典状态。由环境噪声引起的错误可以被建模为作用于量子比特（量子信息的基本单位）的非幺正操作，并且可以通过量子纠错来克服。因此，了解纠缠如何在存在局部测量的量子系统中传播，以及可以使用哪些工具来管理其动力学，不仅是基本问题，而且代表了构建可靠和可扩展的量子处理器的关键步骤。 该职业奖支持对相互作用的量子系统的非平衡动力学的基础研究，从而开发出量子信息处理的新工具，这将成为容错量子处理器的垫脚石。 该项目的一个特别重点是建立暑期实习和研究计划，旨在帮助本科生获得实践早期研究经验，并增加女性和代表性不足的少数民族在量子智能劳动力中的代表性。最近，量子模拟已经成为一种新的工具，可以在数字处理失败的情况下洞察自然现象。到目前为止，量子模拟实验主要集中在由幺正演化描述的孤立系统的动力学上。相反，该项目旨在研究相互作用量子系统的非平衡动力学，这些系统受到良好控制的非幺正操作，通过使用捕获离子系统的独特功能，例如原始的，单独控制的量子位。特别是，这将需要（i）一个破环耗散相变的研究在哈密顿系统中产生的非酉（耗散）操作和酉演化之间的竞争。(ii)体积定律-面积定律纠缠相变的研究，其中纠缠增长作为与环境耦合的强度的函数而急剧变化。（iii）使用多个量子比特编码来存储和检索量子信息，以实现容错捕获离子量子体系结构。该项目将导致幺正和非幺正局域操作的发展，作为利用纠缠进行量子信息处理的强大新工具。该项目中开发的用于实现辅助量子比特的低串扰测量的工具将成为量子纠错和最终容错量子处理器的垫脚石。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Entanglement is the fundamental feature of quantum mechanics that allows quantum processors to tackle specific tasks faster than their classical counterparts. The main challenge in creating and protecting entanglement is posed by decoherence: a quantum system “measured” by the environment loses its quantum correlations and is projected into classical states. Errors caused by environmental noise can be modeled as non-unitary operations acting on the qubits (basic units of quantum information) and can be overcome with quantum error correction. Therefore, understanding how entanglement propagates in quantum systems in the presence of local measurements, and which tools can be employed to govern its dynamics, are not only fundamental questions, but represent crucial steps towards building reliable and scalable quantum processors. This CAREER award supports basic research into the non-equilibrium dynamics of interacting quantum systems leading to the development of new tools for quantum information processing that will be stepping stones towards fault-tolerant quantum processors. A particular focus of this project will be the establishment of summer internship and research programs aimed at helping undergraduate students gain hands-on early research experience and at increasing the representation of women and underrepresented minorities in the quantum smart workforce.Recently, quantum simulation has emerged as a new tool that can provide insight into natural phenomena in regimes where numerical treatments fail. To date, quantum simulation experiments have focused predominantly on the dynamics of isolated systems described by unitary evolution. Conversely, this project aims to investigate non-equilibrium dynamics of interacting quantum systems subjected to well-controlled non-unitary operations, by employing the trapped-ion system’s unique features, such as pristine, individually controlled qubits. In particular, this will entail (i) the study of a symmetry-breaking dissipative phase transitions in Hamiltonian systems stemming from the competition between non-unitary (dissipative) operations and unitary evolution. (ii) The investigation of a volume law-area law entanglement phase transition, where entanglement growth changes dramatically as a function of the strength of the coupling with the environment (iii) The use of multiple qubits encodings to store and retrieve quantum information to enable a fault-tolerant trapped-ion quantum architecture. This project will lead to the development of unitary and non-unitary local operations as a powerful new tool to harness entanglement for quantum information processing. The tools developed in this project to achieve low cross-talk measurements of ancilla qubits will be stepping stones towards quantum error correction and, ultimately, fault-tolerant quantum processors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.