Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 83: Topology: Quantum Hall Systems

TT 83.11: Vortrag

Donnerstag, 12. März 2026, 17:45–18:00, HSZ/0105

The fate of the Laughlin state in ideal Chern bands — •Saranyo Moitra and Inti Sodemann Villadiego — Universität Leipzig, Leipzig, Germany

Ideal Chern bands are believed to be crucial to realizing the recently discovered fractional quantum Hall states at zero magnetic field. However, the nature of even the most archetypical Laughlin states and its competition with other phases remains poorly understood in this setting. We rigorously demonstrate that the Laughlin wave-function in ideal Chern bands is unstable to a novel gapless dielectric phase. Even the celebrated filling 1/3 state crystallizes into a correlated phase with continuously tunable power-law exponents, and quasiparticles with fractional charges varying smoothly below e/3. Remarkably, this state remains gapless without spontaneous symmetry breaking, exemplifying a form of beyond-Goldstone gaplessness. Our results bridge the physics of fractional quantum Hall and Coulomb gases, and we will discuss potential implications of this finding for moiré materials and its possible connections to critical states in other settings.

Keywords: Fractional Chern Insulators; Ideal Chern bands; Laughlin state; BKT phase transition; Moiré Transition Metal Dichalcogenides