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arXiv · 1910.02518

Self-similar dynamics of order parameter fluctuations in pump-probe experiments

Pavel E. Dolgirev·Marios H. Michael·Alfred Zong·Nuh Gedik·Eugene Demler
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Abstract

Upon excitation by a laser pulse, broken-symmetry phases of a wide variety of solids demonstrate similar order parameter dynamics characterized by a dramatic slowing down of relaxation for stronger pump fluences. Motivated by this recurrent phenomenology, we develop a simple non-perturbative effective model of dynamics of collective bosonic excitations in pump-probe experiments. We find that as the system recovers after photoexcitation, it shows universal prethermalized dynamics manifesting a power-law, as opposed to exponential, relaxation, explaining the slowing down of the recovery process. For strong quenches, long-wavelength over-populated transverse modes dominate the long-time dynamics; their distribution function exhibits universal scaling in time and space, whose universal exponents can be computed analytically. Our model offers a unifying description of order parameter fluctuations in a regime far from equilibrium, and our predictions can be tested with available time-resolved techniques.

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Pavel E. Dolgirev, Marios H. Michael, Alfred Zong, Nuh Gedik, Eugene Demler. 2020-05-02. Self-similar dynamics of order parameter fluctuations in pump-probe experiments. https://doi.org/10.1103/physrevb.101.174306

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