Dear CTP/quanta, This Thursday, May 15, Umesh Vazirani will give a talk on finding ground states of 1-D quantum systems. The work builds on his recent breakthroughs in proving area laws in 1-D spin systems, and so is likely to be of interest to all of us who have been thinking about entanglement in ground states. title: A polynomial time algorithm for ground states of 1-D gapped local Hamiltonians abstract: The well-known heuristic DMRG (Density Matrix Renormalization Group) has been the method of choice for the practical solution of 1D systems since its introduction two decades ago by Steve White. However, the reasons for DMRG's success are not theoretically well understood and it is known to fail in certain cases. In this talk, I will describe the first polynomial time classical algorithm for finding ground states of 1D quantum systems described by gapped local Hamiltonians. The algorithm is based on a framework that combines recently discovered structural features of gapped 1D systems, convex programming, and a new and efficient construction of a class of operators called approximate ground state projections (AGSP). An AGSP-centric approach may help guide the search for algorithms for more general quantum systems, including for the central challenge of 2D systems, where even heuristic methods have had very limited success. Joint work with Zeph Landau and Thomas Vidick _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip