On Sak's Criterion for Long-range Interacting Systems
报告人： 邓友金（中国科学技术大学）
时间：2025-11-03 14:00-15:00
地点：智华楼四元厅-225
Abstract:
The crossover between short-range (SR) and long-range (LR) universal behaviors remains a central theme in the physics of long-range interacting systems with algebraically decaying interaction and the crossover position has been a longstanding controversy. One famous conjecture, known as Sak's criterion, is with being the anomalous dimension of the SR case. We conduct Monte Carlo simulations of the two-dimensional (2D) XY model up to a linear size of and obtain continuous phase transitions into a ferromagnetic phase for , exhibiting the simultaneous emergence of a long-range order and a power-law decaying correlation function due to the Goldstone mode. We further extend our study to 2D long-range percolation, Ising, and Heisenberg models and provide strong evidence that for all these cases the crossover point occurs at , raising questions about the validity of Sak’s criterion.
About the Speaker:
邓友金，中国科大教授。1992年考入北京师大，2000年获得北京师大硕士，2004年获得荷兰代尔夫特技术大学博士。随后，在美国纽约大学及德国海德堡大学从事博士后工作。2008年加入中国科大。主要研究方向有计算物理、统计物理及量子模拟理论。在国际物理期刊发表论文200余篇，包括Science, Nature, PNAS , PRX, PRL期刊40余篇。
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