Frank Verstraete - QUTE

Frank VerstraeteFrank Verstraete is professor at the Faculty of Sciences of Ghent University. He obtained a degree of civil engineering in Louvain and of Master in Physics in Ghent, and obtained his PhD on the topic of quantum entanglement in 2002 under supervision of Prof. B. De Moor and Prof. H. Verschelde. He pioneered the use of quantum entanglement as a unifying theme for describing strongly interacting quantum many body systems, which are the most challenging systems to describe but also the most promising for future quantum technologies such as quantum computers. After postdocs at the Max Planck Institute for Quantum Optics (2002-2004) and at the California Institute of Technology (2004-2006), he became the chair of theoretical quantum nanophysics and full professor at the University of Vienna in 2006. He came back to the University of Ghent with an Odysseus grant from the FWO in 2012, and has since built a world leading research group on applications of entanglement in quantum many body systems. He has received numerous awards, and is also distinguished visiting research chair at the Perimeter Institute for theoretical physics in Waterloo, Canada.

QUTE is the second ERC grant which he obtained, the first one on the topic of tensor networks and quantum computation.



Quantum Tensor Networks and Entanglement (QUTE)

One of the major challenges in theoretical physics is the development of systematic methods for describing and simulating quantum many body systems with strong interactions. Given the huge experimental progress and technological potential in manipulating strongly correlated atoms and electrons, there is a pressing need for such a better theory.

The study of quantum entanglement holds the promise of being a game changer for this question. By mapping out the entanglement structure of the low-energy wavefunctions of quantum spin systems on the lattice, the prototypical example of strongly correlated systems, we have found that the associated wavefunctions can be very well modeled by a novel class of variational wavefunctions, called tensor network states. Tensor networks, and in particular matrix product states, projected entangled pair states and the multiscale entanglement renormalization ansatz, are changing the ways in which strongly correlated systems can be simulated, classified and understood: as opposed to the usual many body methods, these tensor networks are generic and describe non-perturbative effects in a very natural way.
The goal of this proposal is to advance the scope and use of tensor networks in several directions, both from the numerical and theoretical point of view. We plan to study the differential geometric character of the manifold of tensor network states and the associated nonlinear differential equations of motion on it, develop post tensor network methods in the form of effective theories on top of the tensor network vacuum, study tensor networks in the context of lattice gauge theories and topologically ordered systems, and investigate the novel insights that tensor networks are providing to the renormalization group and the holographic principle.

Colloquially, we believe that tensor networks and the theory of entanglement provide a basic new vocabulary for describing strongly correlated quantum systems, and the main goal of this proposal is to develop the syntax and semantics of that new language.