Julian Roos

PhD project

Efficient Tensor-Network Algorithms for the Simulation of Many-Body Systems

We use tools from quantum information theory to understand the entanglement structure in low lying quantum many body states. This justifies an efficient representation of such states in the framework of tensor networks and corresponding numerical algorithms have been developed. Such quantum states can now be stored (and thus manipulated) with polynomial instead of exponential resources.
It turns out that there are close analogies between ground states of strongly correlated quantum many body systems and non-equilibrium steady states of classical stochastic processes. [1] The preliminary aim of my project is to employ and develop tensor network algorithms to better understand fluctuations of observables such as current or density profiles in such systems far from equilibrium, where statistical thermodynamics is not available.
[1] K. Temme and F. Verstraete, Phys. Rev. Lett. 104 (2010), 210502

Publications & preprints

[1] J. Roos, C. Eames, S. M. Wood, A. Whiteside and M. S. Islam, “Unusual Mn coordination
and redox chemistry in the high capacity borate cathode Li7Mn(BO3)3”, Phys. Chem. Chem. Phys. 17 (2015), 22259
[2] H. K. Dunn, J. M. Feckl, A. Müller, D. Fattakhova-Rohlfing, S. G. Morehead, J. Roos, L. M. Peter, C. Scheu and T. Bein, “Tin doping speeds up hole transfer during light-driven water oxidation at hematite photoanodes”, Phys. Chem. Chem. Phys. 16(2014), 24610

Conference visits

2013: Materials for Energy (Karlsruhe)
2013: Solar Technologies go Hybrid (München)
2013: AMS Winterschool (Hirschegg)
2014: STFC meeting on Electrochemical Energy Devices (Oxford)
2015: Topological Phases in Condensed Matter and Cold Atom Systems (Cargese)
2016: Lindau Nobel Laureate Meeting (Lindau)

Video Portrait


Max-Planck-Institute for Quantum Optics (MPQ)
Hans-Kopfermann Strasse 1
85748 Garching, Germany
phone: ++49-89-32905-735
e-mail: julian.roos@mpq.mpg.de