The theory of "deconfined" quantum critical points describes phase transitions at temperature T=0 outside the standard paradigm, predicting continuous transformations between certain ordered states where conventional theory requires discontinuities. Numerous computer simulations have offered no proof of such transitions, however, instead finding scaling violations which were neither predicted by the new theory nor conform with standard scenarios. In this talk, I will show this enigma can be resolved by introducing a critical scaling form with two divergent length scales.  I will also present simulation results of a quantum magnet with antiferromagnetic and dimerized ground states which confirm the form, proving a continuous transition with deconfined excitations and also explaining anomalous scaling at T>0. Our findings revise prevailing paradigms for quantum criticality.

郭文安，1990年本科毕业于兰州大学理论物理专业，1993年在兰州大学量子光学专业获硕士学位，1996年北京师范大学统计物理专业获得博士学位；1997-1998年期间在荷兰Delft理工大学担任博士后研究员，1999年加入北京师范大学物理学系任副教授，2004年晋升为教授，2008年入选教育部新世纪优秀人才支持计划。目前郭文安教授课题组主要关注: 低维系统的量子与经典相变，光晶格中冷原子的量子相变, 玻色-爱因斯坦凝聚相关问题。研究手段主要有: 重整化群及标度理论，量子与经典Monte Carlo模拟，数值转移矩阵方法等数值方法。