585 citations · 1.1k across the 46 of their papers we have counts for
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Widths of the Hall Conductance Plateaus
Tohru Koma
We study the charge transport of the noninteracting electron gas in a two-dimensional quantum Hall system with Anderson-type impurities at zero temperature. We prove that there exi…
Friedel Sum Rule as a Trace Formula
Mahito Kohmoto, Tohru Koma
We examine the Friedel sum rule which states that the "excess charge" due to a single impurity potential in a metal is equal to a sum of phase shifts for scatterings of electrons b…
Spectral Gap and Exponential Decay of Correlations
Matthew B. Hastings, Tohru Koma
We study the relation between the spectral gap above the ground state and the decay of the correlations in the ground state in quantum spin and fermion systems with short-range int…
Spectral Gap and Decay of Correlations in U(1)-Symmetric Lattice Systems in Dimensions D<2
Tohru Koma
We consider many-body systems with a global U(1) symmetry on a class of lattices with the (fractal) dimensions D<2 and their zero temperature correlations whose observables behave…