题 目：Critical matters in one dimension
报告人：管习文 研究员（中科院武汉物理与数学研究所）
时 间：7月18日（星期一）上午10:00
地 点：物理楼313报告厅
附报告摘要：
Critical matters in one dimension
X. W. Guan
Wuhan Institute of Physics and Mathematics, Chinese Academy of Science
Department of Theoretical Physics, Research School of Physics and Engi-
neering, Australian National University,Australia
Since last 60's, the 1D spin-1/2 Heisenberg chain is the most extensively studied exactly solvable model. It is an ideal platform for the exploration of quantum magnetism, fractional excitations, Luttinger liquid, thermodynamics, algebraic structure, correlation functions, quantum dynamics and entanglement in literature. However, the quantum criticality of the system is till poorly understood. In this talk, using Takahashi's spin string hypothesis, I will present close forms of scaling functions for magnetization, susceptibility, specific heat that map out the universal critical exponents a, b, d, as well the dynamic critical exponent z and correlation critical exponent n for the perfect spin-1/2 Heisenberg antiferromagnet CuPzN. All measured thermodynamical properties are in excellent agreement with the results obtained from Takahashi's thermodynamic Bethe ansatz equations of the spin chain.
The dimensionless Wilson ratio precisely determine the crossover transition temperatures which were not properly defined in this experiment.
Moreover, I will further discuss our recent observation of quantum criticality and the TLL in a system of ultracold 87Rb atoms within 1D tubes. We observe universal scaling laws, equation of state, speed of sound and Wilson ratio of the 1D Bose gas which are in excellent agreements with the results obtained from the theory of Yang-Yang grand canonical ensemble.
