# Open quantum many-body systems

Dissipation is usually seen as an enemy of coherent evolution, as a decohering process that removes quantum features from the state of a system. It has recently become clear, however, that engineered dissipation can be an ally and help in robust state preparation and manipulation. The interplay between Hamiltonian interactions and open systems dynamics gives rise to new kinds of quantum phase transitions and criticality. We investigate several aspects of this, ranging from more condensed-matter oriented questions, tasks of quantum information processing to mathematical questions relating spatial correlations and mixing.

**Selected group publications**

- Observation of non-Markovian micro-mechanical Brownian motion

Nature Communications 6, 7606 (2015) - Lieb-Robinson bounds for open quantum systems with long-ranged interactions

Journal of Physics A 52, 424003 (2019) - A positive tensor network approach for simulating open quantum many-body systems

Physical Review Letters 116, 237201 (2016) - A dissipative quantum Church-Turing theorem

Physical Review Letters 107, 120501 (2011) - Precisely timing dissipative quantum information processing

Physical Review Letters 110, 110501 (2013) - Percolation, renormalisation, and quantum computing with non-deterministic gates

Physical Review Letters 100, 130501 (2007) - Rapid mixing implies exponential decay of correlations

Journal of Mathematical Physics 54, 102201 (2013) - The complexity of relating quantum channels to master equations

Communications of Mathematical Physics 310, 383 (2012)

**Group review**

- Lieb-Robinson bounds and the simulation of time evolution of local observables in lattice systems

L. D. Site and V. Bach (eds.), Many-Electron Approaches in Physics, Chemistry and Mathematics