Leader: Prof. Dr. Norbert Schuch
The research group "Entanglement of Complex Quantum Systems" works at the interface between strongly correlated many-body systems and quantum information theory. Strongly correlated quantum systems exhibit a wide range of exotic physical phenomena, such as topologically ordered phases with quantised egde currents and exotic excitations, which arise from their intricate entanglement structure. At the same time, the theory of entanglement has been a core topic in quantum information theory, where a wide range of tools to classify, quantify, and utilize entanglement has been developed, suggesting to apply this toolbox to the study of strongly correlated systems.
In our group, we apply quantum information methods to the systematic study of strongly correlated systems, with three main goals: First, we aim to classify the possible phases of strongly correlated systems, this is, the distinct types of global entanglement. Second, we use these insights to study specific strongly correlated systems by means of tailored variational wave functions. Third, we study the fundamental limitations to our understanding of these systems imposed by quantum complexity theory.
An important tool in our study are tensor network states which provide unified a description of a global wavefunction and its associated Hamiltonian based on a single tensor. This tensor encodes all physical properties locally, and thus allows to naturally relate local properties and globally emerging behaviour.