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The charge gap is greater than the neutral gap in fractional quantum Hall systems

Mathematical Physics Seminar

Speaker: Bruno Nachtergaele, UC Davis
Location: 3024 QMAP
Start time: Mon, Nov 18 2024, 3:10PM

Past studies of fractional quantum Hall systems have found that the charge gap dominates the neutral gap for all relevant parameter choices. We report a wide-ranging proof that this domination is in fact a universal property of any Hamiltonian that satisfies a few simple structural properties: translation-invariance, charge conservation, dipole conservation, and a fractionally filled ground state. The result applies to both fermions and bosons. Our main tool is a new mathematical scheme, the gap comparison method, which provides a sequence of inequalities that relate the spectral gaps in successive particle number sectors.  Based on joint work with Marius Lemm, Simone Warzel, and Amanda Young (arXiv:2410.11645)