2015/08/31 by Shawn X. Cui, Michael Freedman, Michael H. Freedman +3 · 27 citations
Computer Science · Mathematics · Physics and Astronomy · #Combinatorics #Flow (mathematics) #Geometry #Mathematics #Maximum cut #Physics #Pure mathematics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum discord #Quantum entanglement #Quantum many-body systems #Quantum mechanics #Tensor product #cs.IT #math.CO #math.IT #msc:81P45 #msc:94A15 #msc:94A17 #quant-ph
paper · pdf · doi:10.1063/1.4954231
published in Journal of Mathematical Physics 57(6) (American Institute of Physics) · added some motivations; added references on relevant work
openalex publication_date 2016/06/01 · arxiv created 2016/06/30 · arxiv updated 2016/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts of the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.