Recorded 09 February 2024. Norbert Schuch of the University of Vienna presents "Tensor networks and the negative sign problem" at IPAM's Tensor Networks Workshop. Abstract: It is well known that quantum systems with negative entries in their Hamiltonian are generally much harder to simulate than those with positive entries only. We show that a similar transition in hardness also shows up in tensor network simulations: Tensor networks with negative entries are generally much harder to contract than those with positive entries only, and carry a much larger amount of correlations. Learn more online at: https://www.ipam.ucla.edu/programs/workshops/tensor-networks/