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arXiv · 1801.09106

Matrix product states and the quantum max-flow/min-cut conjectures

Fulvio Gesmundo·J. M. Landsberg·Michael Walter
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Abstract

In this note we discuss the geometry of matrix product states with periodic boundary conditions and provide three infinite sequences of examples where the quantum max-flow is strictly less than the quantum min-cut. In the first we fix the underlying graph to be a 4-cycle and verify a prediction of Hastings that inequality occurs for infinitely many bond dimensions. In the second we generalize this result to a 2d-cycle. In the third we show that the 2d-cycle with periodic boundary conditions gives inequality for all d when all bond dimensions equal two, namely a gap of at least 2^{d-2} between the quantum max-flow and the quantum min-cut.

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Fulvio Gesmundo, J. M. Landsberg, Michael Walter. 2018-10-18. Matrix product states and the quantum max-flow/min-cut conjectures. https://doi.org/10.1063/1.5026985

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