Quantum Simulation of Out-of-Equilibrium Spin Models

非平衡自旋模型的量子模拟

• 批准号: 1915218
• 负责人: Paola Cappellaro
• 金额: $ 37.93万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1915218&HistoricalAwards=false
• 关键词: Quantum; Simulation; Out; Equilibrium; Spin

Simulating complex systems on a computer improves our understanding of natural phenomena and helps to develope new technology. Yet, some systems are beyond the simulation capabilities of even the most advanced supercomputers. Quantum simulators could overcome this challenge and greatly impact quantum chemistry, material science, condensed matter, and high-energy physics. While general-purpose quantum computers promise to more broadly revolutionize computing, they are still in their infancy, while quantum simulators can already tackle some task-specific problems. This is achieved by following a different approach than computer-based simulators, by using one quantum system to directly mimic the evolution of another, target system. The weakness in this strategy is that it lacks flexibility. This project aims to expand the capabilities of quantum simulation by introducing programmable analog quantum simulators which combine the ease of directly mimicking a system evolution, with the flexibility of engineering the simulator dynamics via logic gates. In addition, the project will develop novel metrics to evaluate performance and to acquire the most comprehensive information about the simulated system.To achieve these goals, the researchers will employ a hybrid approach, combining evolution under the natural Hamiltonian (as in analog quantum simulators) with periodic control (collective quantum gates) to engineer a Floquet Hamiltonian approximating the interaction models of interest. As the simulation performance should be assessed on large (scalable) quantum systems not accessible to classical simulators, the project will validate the quantum control protocols experimentally, devising experimentally accessible metrics that can characterize the many-body dynamics, such as out-of-time ordered correlations and Loschmidt echoes. The systems used as quantum simulators will include quasi-1D nuclear spin chains, nuclear spins in 3D crystals, and spin impurities in diamond. There are several advantages of using spin systems to address these questions over synthetic matter systems such as cold atoms and ions. First, the system directly maps to typical spin Hamiltonians studied theoretically and it can build upon the long tradition of magnetic resonance investigation of condensed matter physics. In addition, these spin systems allow exploring broader regimes than cold atoms and ions, for example high-temperature conditions, and conditions that are well beyond what can be simulated exactly, such as large, 3D systems, and open systems interacting with a well-defined environment. Exploring the out-of-equilibrium dynamics of such rich spin systems will bring forward a host of new physical phenomena, as it will be demonstrated with a few paradigmatic examples of quantum spin models. A particular focus of the project is on investigating quantum thermalization or its absence due to localization or prethermalization, a key question in the quest to exploit many-body systems for quantum applications.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.

在计算机上模拟复杂的系统可以提高我们对自然现象的理解，并有助于开发新技术。然而，有些系统甚至超出了最先进的超级计算机的模拟能力。量子模拟器可以克服这一挑战，并极大地影响量子化学，材料科学，凝聚态和高能物理。虽然通用量子计算机有望更广泛地改变计算，但它们仍处于起步阶段，而量子模拟器已经可以解决一些特定任务的问题。这是通过采用与基于计算机的模拟器不同的方法来实现的，即使用一个量子系统直接模拟另一个目标系统的演化。这种策略的缺点是缺乏灵活性。该项目旨在通过引入可编程模拟量子模拟器来扩展量子模拟的能力，该模拟器联合收割机结合了直接模拟系统演化的便利性和通过逻辑门设计模拟器动态的灵活性。此外，该项目还将开发新的指标来评估性能，并获得有关模拟系统的最全面信息。为了实现这些目标，研究人员将采用混合方法，将自然哈密顿量下的进化（如模拟量子模拟器）与周期控制（集体量子门）相结合，以设计一个近似感兴趣的相互作用模型的Floquet哈密顿量。由于模拟性能应该在经典模拟器无法访问的大型（可扩展）量子系统上进行评估，因此该项目将通过实验验证量子控制协议，设计可以表征多体动力学的实验可访问度量，例如超时有序相关性和Loschirm回波。用作量子模拟器的系统将包括准1D核自旋链、3D晶体中的核自旋和金刚石中的自旋杂质。使用自旋系统来解决这些问题有几个优点，而不是像冷原子和离子这样的合成物质系统。首先，该系统直接映射到理论上研究的典型自旋哈密顿量，它可以建立在凝聚态物理的磁共振研究的悠久传统之上。此外，这些自旋系统允许探索比冷原子和离子更广泛的机制，例如高温条件，以及远远超出可以精确模拟的条件，例如大型3D系统和与明确定义的环境相互作用的开放系统。探索这种丰富的自旋系统的非平衡动力学将带来许多新的物理现象，因为它将被证明与量子自旋模型的一些范例。该项目的一个特别重点是研究量子热化或由于局部化或预热化而导致的量子热化的缺失，这是探索多体系统量子应用的关键问题。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Observation of Symmetry-Protected Selection Rules in Periodically Driven Quantum Systems

周期性驱动量子系统中对称保护选择规则的观察

• DOI: 10.1103/physrevlett.127.140604
• 发表时间: 2021
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Wang, Guoqing;Li, Changhao;Cappellaro, Paola
• 通讯作者: Cappellaro, Paola

Comparing many-body localization lengths via nonperturbative construction of local integrals of motion

通过局部运动积分的非微扰构造来比较多体定位长度

• DOI: 10.1103/physrevb.100.214203
• 发表时间: 2019
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Peng, Pai;Li, Zeyang;Yan, Haoxiong;Wei, Ken Xuan;Cappellaro, Paola
• 通讯作者: Cappellaro, Paola

High-fidelity Trotter formulas for digital quantum simulation

用于数字量子模拟的高保真 Trotter 公式

• DOI: 10.1103/physreva.102.010601
• 发表时间: 2020
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: Liu, Yi-Xiang;Hines, Jordan;Li, Zhi;Ajoy, Ashok;Cappellaro, Paola
• 通讯作者: Cappellaro, Paola

Floquet prethermalization in dipolar spin chains

• DOI: 10.1038/s41567-020-01120-z
• 发表时间: 2021-01
• 期刊: Nature Physics
• 影响因子: 19.6
• 作者: Pai Peng;Chao Yin;Xiaoyang Huang;C. Ramanathan;P. Cappellaro

Observation of a Prethermal U(1) Discrete Time Crystal

预热 U(1) 离散时间晶体的观测

• DOI: 10.1103/physrevx.13.041016
• 发表时间: 2023
• 期刊: Physical Review X
• 影响因子: 12.5
• 作者: Stasiuk, Andrew;Cappellaro, Paola
• 通讯作者: Cappellaro, Paola