Research


Quantum mechanics is one of the biggest breakthroughs in the history of physics. At the beginning of the 20th century its founding fathers like Planck, Bohr, De Broglie, Schrodinger, Heisenberg and Dirac were not only confronted with unexpected conceptual difficulties but also had to introduce new mathematical techniques in the area of physics to get their head around this revolutionary new way of thinking. But successful applications of the theory in for example the hydrogen atom showed that quantum mechanics was the way to go.

Today, almost a century later, physicists are still struggling to fully understand the implications of quantum mechanics. Especially in systems with many degrees of freedom it is extremely challenging to calculate the predictions made by this theory. The reason for this is that the complexity of the problem escalates very quickly with number of degrees of freedom, even exponentially to be precise.

In recent years insights from quantum information theory were used to tackle the quantum many-body problem. It was realized that in many cases the locality of interactions has a profound influence on the entanglement structure of the ground and other low energy states. Out of this arose the so called ‘tensor network states’, which are an ansatz for the ground state of the many-body system that capture the relevant entanglement structure. Tensor network states allow for a more efficient use of time and resources since one no longer has to look for the correct answer in the entire space of possible states, restricting to the physical subspace of tensor network states is sufficient. The local structure of these states also provide ways to get a deeper understanding of generic emergent phenomena in quantum many-body systems and their connection to entanglement.

Tensor network states are finding their way in an increasing number of fields in physics, ranging from condensed matter theory to quantum gravity. In the Ghent university quantum group of Prof. Verstraete we are at the forefront of many of these applications, with an expertise in both the theoretical and numerical aspects.

Below we list the topics of active research in our quantum group and provide additional details.