title: Emergent Spacetime Supersymmetry in 3D Weyl Semimetals and 2D Dirac Semimetals.
abstract: Supersymmetry (SUSY) interchanges bosons and fermions but no direct evidence of it has been revealed in nature yet. In this Letter, we observe that fluctuating pair density waves (PDW) consist of two complex order parameters which can be superpartners of the unavoidably doubled Weyl fermions in three-dimensional lattice models. We construct explicit fermionic lattice models featuring 3D Weyl fermions and show that PDW is the leading instability via a continuous phase transition as short-range interactions exceed a critical value. Using a renormalization group, we theoretically show that N=2 space-time SUSY emerges at the continuous PDW transitions in 3D Weyl semimetals, which we believe is the first realization of emergent (3+1)D space-time SUSY in microscopic lattice models. We further discuss possible routes to realize such lattice models and experimental signatures of emergent SUSY at the PDW criticality.
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Shao-Kai
authors.initials: SK
authors.lastname: Jian
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.|Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Jiang
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yao