Generalized thermodynamic closure in ultrafast phonon dynamics

arXiv (Cornell University)

Abstract

Driven-dissipative dynamics underlie a wide range of nonequilibrium phenomena in quantum materials, yet reduced descriptions beyond the quasi-equilibrium picture remain difficult to establish. Here, we experimentally demonstrate that a resonantly driven phonon mode admits a generalized thermodynamic description in which coherence and energy jointly organize the nonequilibrium evolution. Beyond a threshold driving field strength, we observe a delayed ultrafast response of a coherently driven phonon mode. Combined with experimentally constrained Lindblad dynamics, we show that this delay reflects the finite-time spreading of excitations across many phonon levels. At the same time, the full density-matrix trajectories for three driving conditions collapse onto a common surface defined by energy and coherence. Our results establish a coherence-extended thermodynamic regime for driven phonons and provide a framework for broader state engineering in driven-dissipative bosonic excitations.

Authors 12

1. Sheng Qu
2. Jiyong Kim

   Pohang University of Science and Technology

   Affiliation as printed

   Department of Physics , Pohang University of Science and Technology , Pohang , 37673 , Korea

3. Jaco J. Geuchies Aachen

   Leiden University · University of Applied Sciences Leiden

   Affiliation as printed

   Leiden Institute of Chemistry , Leiden University , Leiden , 2333CC , Netherlands

4. Sergey Kovalev

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

5. Jan‐Christoph Deinert

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

6. Thales de Oliveira

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

7. Alexey N. Ponomaryov

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

8. Min Chen

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

9. Nilesh Awari

   Helmholtz-Zentrum Dresden-Rossendorf

   Affiliation as printed

   Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

10. Igor E. Ilyakov

    Helmholtz-Zentrum Dresden-Rossendorf

    Affiliation as printed

    Institute of Radiation Physics , Helmholtz-Zentrum Dresden-Rossendorf , Dresden , 01328 , Germany

11. Mischa Bonn
12. Heejae Kim

    Pohang University of Science and Technology · Max Planck Institute for Polymer Research

    Affiliation as printed

    Department of Molecular Spectroscopy , Max-Planck Institute for Polymer Research , Mainz , 55128 , Germany

    Department of Physics , Pohang University of Science and Technology , Pohang , 37673 , Korea