Entrada Departamento Notícias QuantumMatter@PT: 5th Quantum Colloquium - Roderick Moessner (Thursday 4 March, 17h-18h)

QuantumMatter@PT: 5th Quantum Colloquium - Roderick Moessner (Thursday 4 March, 17h-18h)

Thermodynamics and Order Beyond Equilibrium From Eigenstate Thermalisation to Time Crystals

Roderich Moessner

Max Planck Institute for the Physics of Complex Systems

Dresden, Germany



The field of thermodynamics is one of the crown jewels of classical physics. Thanks to the advent of experiments in cold atomic systems with long coherence times, our understanding of the connection between thermodynamics and quantum statistical mechanics has seen remarkable progress. Extending these ideas and concepts to the non-equilibrium setting is a challenging topic, in itself of perennial interest. Here, we present perhaps the simplest non-equilibrium class of quantum problems, namely Floquet systems, i.e. systems whose Hamiltonians depend periodically on time, H(t+T)=H(t) . For these, there is no energy conservation, and hence not even a natural concept of temperature. We find that certain structures from equilibrium thermodynamics are lost, while entirely new non-equilibrium phenomena can arise, including a spectacular spatiotemporal ‘time-crystalline’ form of order.


[1] R. Moessner and S. L. Sondhi, Nature Physics 13, 424–428 (2017)

[2] V. Khemani, R. Moessner and S. L. Sondhi, A Brief History of Time Crystals, arXiv:1910.10745 (2019)

Biographic Info:

Roderich Moessner is a condensed-matter physicist with important contributions in the study of strong fluctuations in many-body systems due to frustration, competing degrees of freedom, or quantum fluctuations. He got his Ph.D. from Oxford University and after that worked at Princeton University and at the Ecole Normale Supérieure. Roderich Moessner currently serves as a director of the Max Planck Institute for the Physics of Complex Systems in Dresden. He has recognized works in a wide range of topics. One of his important contributions was in the theoretical understanding of spin ice. He was awarded various prestigious prizes in his career, namely the 2013 Gottfried Wilhelm Leibniz Prize and 2012 Europhysics Prize of the European Physical Society. He is also a fellow of the American Physical Society and an executive board member of the German Physical Society.

Organizers: P. Ribeiro (IST), E. V. Castro (UP), J. Viana Lopes (UP) and Bruno Amorim (UM)

Co-organizers: M. Gonçalves (IST) and J. P. Santos Pires (UP).

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