| 活动类型： | 学术活动 |
|---|---|
| 活动名称： | 西湖大学严正教授学术报告 |
| 地点： | 中关村-6号楼三层第三会议室 |
| 主讲人： | 张龙 |
| 联系人： | 张龙 |
| 联系方式： | 13511071504 |
| 开始时间： | 2025-06-24 10:00 |
| 结束时间： | 2025-06-24 12:00 |
| 说明: |
Extracting fine-level entanglement spectrum from 2D quantum many-body systems and probing the emergent symmetries of critical points The reduced density matrix (RDM) plays a key role in quantum entanglement and measurement, as it allows the extraction of almost all physical quantities related to the reduced degrees of freedom. However, restricted by the degrees of freedom in the environment, the total system size is often limited, let alone the subsystem. To address this challenge, we propose a quantum Monte Carlo scheme with a low technical barrier, enabling precise extraction of the RDM. To demonstrate the power of the method, we present the fine levels of the entanglement spectrum (ES), which is the logarithmic eigenvalues of the RDM. Meanwhile, the (emergent) symmetry of a critical point is one of the most important information to identify the universality class and effective field theory, which is fundamental for various critical theories. However, the underlying symmetry so far can only be conjectured indirectly from the dimension of the order parameters in symmetry-breaking phases, and its correctness requires further verifications to avoid overlooking hidden order parameters, which by itself is also a difficult task. We propose using the ES to identify the underlying (emergent) symmetry of a critical point in quantum many-body systems, without prior knowledge about its low-energy effective field theory. It’s because the Anderson tower of states in the ES clearly reflects the underlying (emergent) symmetry of the criticality. It is attributed to the fact that the entanglement spectrum can observe the broken symmetry of the entanglement ground-state after cooling from the critical point along an extra temperature axis. |