SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 3: Focus Session: Entanglement as a Probe for Correlated Quantum Matter

TT 3.2: Talk

Monday, September 27, 2021, 14:00–14:30, H6

Observation of E₈ particles in Ising chain quantum magnets — •Zhe Wang — Department of Physics, TU Dortmund University, Dortmund, Germany

Near the transverse-field-induced quantum critical point of the Ising chain, an exotic dynamic spectrum consisting of exactly eight particles was predicted [1], which is uniquely described by an emergent quantum integrable field theory with the E₈ Lie algebra, but rarely explored experimentally. By performing high-resolution terahertz spectroscopy of quantum spin dynamics and comparing to analytical calculation of the dynamical spin correlations, we revealed evidence for the E₈ particles in the Ising chain antiferromagnet BaCo₂V₂O₈ [2] as well as in the Ising chain ferromagnet CoNb₂O₆ [3] under an applied transverse field. In particular, higher-energy E₈ particles were observed above the low-lying two-particle continua, featuring the quantum many-body effects in the exotic dynamic spectrum [2,3].
[1] A. B. Zamolodchikov, Int. J. Mod. Phys. A 4, 4235 (1989).
[2] Z. Zhang et al., Phys. Rev. B 101, 220411 (2020).
[3] K. Amelin et al., Phys. Rev. B 102, 104431 (2020).