Shaking Strongly Correlated Electrons   

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Periodically driven quantum many-body systems (such as cold atoms in time-dependent optical lattices and quantum materials under ultra-fast optical excitation) offer exciting perspectives of exploring quantum phases of matter along genuine non-equilibrium pathways.This so-called Floquet engineering relies, however, on the suppression of heating, i.e. the uncontrolled energy absorption from the drive. This was known to be the case only in the limit of extremely high frequency,thus limiting its practical use.

A team at IPhT around Francesco PeronaciMarco Schiro and Olivier Parcollet showed that also strong electronic interactions can largely circumvent energy absorption, and thus provide a robust
platform for Floquet engineering even at finite frequency. This is demonstrated with non-equilibrium dynamical mean-field calculations
on a driven Fermi-Hubbard model, a paradigmatic example of lattice correlated electrons. The microscopic mechanism for this Floquet prethermalization is the kinematic constraint on the production of large-energy excitations known as doublons. Interestingly, when the drive frequency is made resonant with the doublon energy, heating is abruptly recoverd, unveiling a new type of dynamical phase transition.

Reference:
F. Peronaci, M. Schiró and O. Parcollet, Physical Review Letters 120 (19), 197601.

 

 
C. Pepin, 2018-12-13

 

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