article published yes Christopher Turner author Alexios Michailidis author 36EBAD38-F248-11E8-B48F-1D18A9856A870000-0002-8443-1064 Dmitry Abanin author Maksym Serbyn author 47809E7E-F248-11E8-B48F-1D18A9856A870000-0002-2399-5827 Zlatko Papić author MaSe department The thermodynamic description of many-particle systems rests on the assumption of ergodicity, the ability of a system to explore all allowed configurations in the phase space. Recent studies on many-body localization have revealed the existence of systems that strongly violate ergodicity in the presence of quenched disorder. Here, we demonstrate that ergodicity can be weakly broken by a different mechanism, arising from the presence of special eigenstates in the many-body spectrum that are reminiscent of quantum scars in chaotic non-interacting systems. In the single-particle case, quantum scars correspond to wavefunctions that concentrate in the vicinity of unstable periodic classical trajectories. We show that many-body scars appear in the Fibonacci chain, a model with a constrained local Hilbert space that has recently been experimentally realized in a Rydberg-atom quantum simulator. The quantum scarred eigenstates are embedded throughout the otherwise thermalizing many-body spectrum but lead to direct experimental signatures, as we show for periodic recurrences that reproduce those observed in the experiment. Our results suggest that scarred many-body bands give rise to a new universality class of quantum dynamics, opening up opportunities for the creation of novel states with long-lived coherence in systems that are now experimentally realizable. Nature Publishing Group2018 eng 00043825360002810.1038/s41567-018-0137-5 14745 - 749 Turner, Christopher, et al. “Weak Ergodicity Breaking from Quantum Many-Body Scars.” <i>Nature Physics</i>, vol. 14, Nature Publishing Group, 2018, pp. 745–49, doi:<a href="https://doi.org/10.1038/s41567-018-0137-5">10.1038/s41567-018-0137-5</a>. C. Turner, A. Michailidis, D. Abanin, M. Serbyn, and Z. Papić, “Weak ergodicity breaking from quantum many-body scars,” <i>Nature Physics</i>, vol. 14. Nature Publishing Group, pp. 745–749, 2018. Turner, C., Michailidis, A., Abanin, D., Serbyn, M., &#38; Papić, Z. (2018). Weak ergodicity breaking from quantum many-body scars. <i>Nature Physics</i>. Nature Publishing Group. <a href="https://doi.org/10.1038/s41567-018-0137-5">https://doi.org/10.1038/s41567-018-0137-5</a> Turner C, Michailidis A, Abanin D, Serbyn M, Papić Z. Weak ergodicity breaking from quantum many-body scars. <i>Nature Physics</i>. 2018;14:745-749. doi:<a href="https://doi.org/10.1038/s41567-018-0137-5">10.1038/s41567-018-0137-5</a> Turner, Christopher, Alexios Michailidis, Dmitry Abanin, Maksym Serbyn, and Zlatko Papić. “Weak Ergodicity Breaking from Quantum Many-Body Scars.” <i>Nature Physics</i>. Nature Publishing Group, 2018. <a href="https://doi.org/10.1038/s41567-018-0137-5">https://doi.org/10.1038/s41567-018-0137-5</a>. C. Turner, A. Michailidis, D. Abanin, M. Serbyn, Z. Papić, Nature Physics 14 (2018) 745–749. Turner C, Michailidis A, Abanin D, Serbyn M, Papić Z. 2018. Weak ergodicity breaking from quantum many-body scars. Nature Physics. 14, 745–749. 2962018-12-11T11:45:40Z2023-09-19T10:37:55Z