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Gauge Fields, Mode Mixing and Local Density of States in a Quantum Point Contact

S. Ulreich·W. Zwerger
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Abstract

It is shown that the elimination of the discrete transverse motion in a waveguide of arbitrary shape may be described in terms of a non-abelian gauge field for the longitudinal dynamics. This allows for an exact treatment of the scattering between different modes by eliminating the gauge field at the expense of a non-diagonal matrix of local subband energies. The method is applied to calculate the local density of states (LDOS) in a quantum point contact. Contrary to the total conductance which is well described by an adiabatic approximation, mode mixing turns out to play a crucial role for local properties like the LDOS.

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S. Ulreich, W. Zwerger. 1997-10-17. Gauge Fields, Mode Mixing and Local Density of States in a Quantum Point Contact. https://arxiv.org/abs/cond-mat/9710174

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