近日，美国麻省理工学院的William D. Oliver及其研究小组与美国谷歌量子人工智能公司的Amir H. Karamlou等人合作并取得一项新进展。经过不懈努力，他们对二维硬核玻色-哈伯德晶格中的纠缠进行探测。相关研究成果已于2024年4月24日在国际权威学术期刊《自然》上发表。
该研究团队使用可控的4 × 4超导量子比特阵列来模拟二维硬核玻色-哈伯德(HCBH)晶格。研究人员通过同时驱动所有晶格格位产生叠加态，并在其多体能谱中提取相关长度和纠缠熵。研究人员观察到光谱中心状态的体积定律纠缠缩放，以及在其边缘附近开始的面积定律缩放的交叉。研究人员利用可控的4 × 4超导量子比特阵列模拟二维硬核玻色-哈伯德晶格，观察了能谱中不同位置的体积定律纠缠标度和面积定律标度。
据悉，纠缠及其传播是理解量子系统许多物理特性的核心。值得注意的是，在封闭量子多体系统中，纠缠被认为会产生涌现的热力学行为。然而，由于大多数大规模量子系统的不可积性和计算难解性，全面理解仍然具有挑战性。量子硬件平台为研究相互作用多体系统中纠缠的形成和尺度提供了一种手段。
附：英文原文
Title: Probing entanglement in a 2D hard-core Bose–Hubbard lattice
Author: Karamlou, Amir H., Rosen, Ilan T., Muschinske, Sarah E., Barrett, Cora N., Di Paolo, Agustin, Ding, Leon, Harrington, Patrick M., Hays, Max, Das, Rabindra, Kim, David K., Niedzielski, Bethany M., Schuldt, Meghan, Serniak, Kyle, Schwartz, Mollie E., Yoder, Jonilyn L., Gustavsson, Simon, Yanay, Yariv, Grover, Jeffrey A., Oliver, William D.
Issue&Volume: 2024-04-24
Abstract: Entanglement and its propagation are central to understanding many physical properties of quantum systems. Notably, within closed quantum many-body systems, entanglement is believed to yield emergent thermodynamic behaviour. However, a universal understanding remains challenging owing to the non-integrability and computational intractability of most large-scale quantum systems. Quantum hardware platforms provide a means to study the formation and scaling of entanglement in interacting many-body systems. Here we use a controllable 4 × 4 array of superconducting qubits to emulate a 2D hard-core Bose–Hubbard (HCBH) lattice. We generate superposition states by simultaneously driving all lattice sites and extract correlation lengths and entanglement entropy across its many-body energy spectrum. We observe volume-law entanglement scaling for states at the centre of the spectrum and a crossover to the onset of area-law scaling near its edges. By emulating a 2D hard-core Bose–Hubbard lattice using a controllable 4 × 4 array of superconducting qubits, volume-law entanglement scaling as well as area-law scaling at different locations in the energy spectrum are observed.
DOI: 10.1038/s41586-024-07325-z
