One remarkable consequence of the strong electronic correlation in quantum materials is the emergence of new quasiparticles that are fundamentally different from electrons. Identification of these quasiparticles is a central question but remains a huge challenge, especially when they are charge neutral. One exciting platform for hunting the neutral quasiparticles is the quantum spin liquid (QSL) stabilized in Mott insulators. Despite the existence of QSL being well established by several exactly solvable models, a conclusive identification by experiment is still lacking. In this talk, I will discuss our recent efforts [1, 2] to study the remnant charge signature associated with QSL in Mott insulators, which may serve as smoking gun evidence for the existence of QSL. I will present two mechanisms, which are closely related to the well-known Landau diamagnetism in metals and the Meissner effect in superconductors, on how neutral quasiparticles develop charged responses. I will demonstrate these mechanisms through the model calculations of Kitaev QSL and chiral QSL.

[1] Saikat Banerjee, Shi-Zeng Lin, arXiv:2208.06887
[2] Shi-Zeng Lin, arXiv:2210.06550