When the quantum critical transverse-field Ising chain is perturbed by a longitudinal field, a quantum integrable model emerges in the scaling limit with massive excitations described by the exceptional $E_{8}$ Lie algebra. Using the corresponding analytical form factors of the quantum $E_{8}$ integrable model, we systematically study the spin dynamic structure factor of the perturbed quantum critical Ising chain, where particle channels with total energy up to 5$m_1$ ($m_1$ being the mass of the lightest $E_{8}$ particle) are exhausted. In addition to the significant single-particle contributions to the dynamic spectrum, each two-particle channel with different masses is found to exhibit an edge singularity at the threshold of the total mass and decays with an inverse square root of energy, which is attributed to the singularity of the two-particle density of states at the threshold. The singularity is absent for particles with equal masses due to a cancellation mechanism involving the structure of the form factors. As a consequence, the dynamic structure factor displays a cascade of bumping peaks in the continuum region with clear singular features which can serve as a solid guidance for the material realization of the quantum $E_{8}$ model.
Finite temperature spin dynamics in a perturbed quantum critical Ising chain with an $E_8$ symmetry
当在横向场伊辛链的量子临界点处引入一个小的纵向场时,预计会出现一个表现出$E_8$对称性的光谱。这一光谱的证据最近来自于准一维伊辛铁磁体钴酸盐的中子散射测量。与零温模型不同,该模型的有限温度动力学尚未确定。我们用形状因子方法研究了该模型在低频非零温度下的动态自旋结构因子。它的频率依赖性是奇异的,但不同于扩散形式。的温度依赖性的核磁共振(NMR)弛豫速率有一个激活的形式,其前因子,我们也确定。我们建议NMR实验作为一种手段,以进一步测试的适用性的$E_8$描述CoNb $_2$ O $_6$。
Cascade of Spin Liquids in a Bilayer Triangular-lattice Antiferromagnet Rb_2Co_2(SeO_3)_3
Renmin University of China(中国人民大学);Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences(中国科学院合肥物质科学研究院高磁强场实验室)
Excitations in the quantum paramagnetic phase of the quasi-one-dimensional Ising magnet CoNb$_2$O$_6$ in a transverse field: Geometric frustration and quantum renormalization effects
准一维Ising铁磁体CoNb $_2$ O $_6$在外加横向磁场的作用下发生了从自发磁序到量子顺磁序的连续量子相变,观察到自旋动力学的显著变化,表现出弱微扰的一维Ising量子临界特性.我们在这里报告广泛的单晶非弹性中子散射测量的磁激发在整个三维(3D)布里渊区的量子顺磁相刚好在临界场以上的有限链间耦合的影响进行表征。在这个阶段,我们观察到,激发有一个尖锐的,分辨率有限的线形在低能量和大部分的色散带宽,自旋翻转准粒子的预期。我们沿着强色散链方向映射的全带宽,并解决明确调制的色散在垂直于链的平面中,在反铁磁等腰三角形晶格中的链间耦合的特性受挫。分散体可以很好地参数化使用线性自旋波模型,包括链间耦合和进一步的邻居交换。沿链方向观察到的色散带宽小于线性自旋波模型使用在零场确定的交换值所预测的,这种效应归因于量子重整化的色散超出自旋波近似在略高于临界场的领域,量子波动仍然显着。
Crosscap states and duality of Ising field theory in two dimensions
Faculty of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München(慕尼黑大学物理学院与阿诺德·索末菲理论物理中心);School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology(华中科技大学物理学院与武汉国家强磁场科学中心);Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);Songshan Lake Materials Laboratory(松山湖材料实验室)
A Numerical Renormalization Group for Continuum One-Dimensional Systems
我们提出了一个重整化群(RG)的过程,自然地工作在一类广泛的相互作用的一维模型的基础上扰动(可能强烈)连续共形和可积模型。这个程序将Kenneth Wilson的数值重整化群与Al. B. Zamolodchikov的截断共形谱方法。该方法的关键是,这些理论提供了一组完全理解的本征态,可以精确计算矩阵元素。在这个过程中,RG流的物理可观的数值和分析研究。为了证明这种方法,我们研究了一对耦合的量子伊辛链的光谱和关联函数在一个单一的量子伊辛链在磁场的存在下。
Emergent superconformal symmetry in the phase diagram of a 1D $\mathbb{Z}_{2}$ lattice gauge theory
Karlstad University(卡尔斯特大学);Andronikashvili Institute of Physics(安德罗尼卡什维利物理研究所);Ilia State University(伊利亚州立大学);Heinrich-Heine-Universität(海因里希·海涅大学);Nordita, KTH Royal Institute of Technology and Stockholm University(诺迪塔,皇家理工学院与斯德哥尔摩大学)
The Abdus Salam International Centre for Theoretical Physics (ICTP)(阿卜杜斯·萨拉姆国际理论物理中心);Università di Padova(帕多瓦大学);Technical University of Munich(慕尼黑工业大学);International School for Advanced Studies (SISSA)(高级研究国际学院);INFN Sezione di Trieste(意大利国家核物理研究所的里雅斯特分部);Ecole Polytechnique Fédérale de Lausanne (EPFL)(洛桑联邦理工学院);Università di Bologna(博洛尼亚大学)