Persistent coherence of quantum superpositions in an optimally doped cuprate revealed by 2D spectroscopy

Fabio Novelli; Jonathan O Tollerud; Dharmalingam Prabhakaran; Jeffrey A Davis

doi:10.1126/sciadv.aaw9932

Persistent coherence of quantum superpositions in an optimally doped cuprate revealed by 2D spectroscopy

Sci Adv. 2020 Feb 28;6(9):eaaw9932. doi: 10.1126/sciadv.aaw9932. eCollection 2020 Feb.

Authors

Fabio Novelli^{1

2}, Jonathan O Tollerud¹, Dharmalingam Prabhakaran³, Jeffrey A Davis^{1

4}

Affiliations

¹ Centre for Quantum and Optical Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
² Department of Physical Chemistry II, Ruhr University Bochum, 44801 Bochum, Germany.
³ Department of Physics, University of Oxford, Oxford OX1 3PU, UK.
⁴ ARC Centre of Excellence for Future Low-Energy Electronics Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.

Abstract

Quantum materials displaying intriguing magnetic and electronic properties could be key to the development of future technologies. However, it is poorly understood how the macroscopic behavior emerges in complex materials with strong electronic correlations. While measurements of the dynamics of excited electronic populations have been able to give some insight, they have largely neglected the intricate dynamics of quantum coherence. Here, we apply multidimensional coherent spectroscopy to a prototypical cuprate and report unprecedented coherent dynamics persisting for ~500 fs, originating directly from the quantum superposition of optically excited states separated by 20 to 60 meV. These results reveal that the states in this energy range are correlated with the optically excited states at ~1.5 eV and point to nontrivial interactions between quantum many-body states on the different energy scales. In revealing these dynamics and correlations, we demonstrate that multidimensional coherent spectroscopy can interrogate complex quantum materials in unprecedented ways.

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).