Explore the challenges of simulating quantum systems with negative Hamiltonian entries in this 51-minute lecture by Norbert Schuch from the University of Vienna. Delve into the concept of tensor networks and their role in quantum simulations. Discover how the presence of negative entries in tensor networks significantly increases the complexity of contraction and the amount of correlations they can represent. Compare the computational difficulties between systems with positive-only entries and those with negative components. Gain insights into the implications of the "negative sign problem" for both quantum system simulations and tensor network calculations. Enhance your understanding of advanced concepts in quantum physics and computational methods presented at IPAM's Tensor Networks Workshop at UCLA.