Observation of the magnonic Dicke superradiant phase transition
Two-level atoms ultrastrongly coupled with single-mode cavity photons are predicted to exhibit a quantum phase transition, entering a phase in which both the atomic polarization and the photonic field are finite even without external driving. However, this phenomenon, the superradiant phase transition (SRPT), is forbidden by a no-go theorem due to the existence of the diamagnetic term. Here, we present spectroscopic evidence for a magnonic SRPT in ErFeO<sub>3</sub>, where the role of the photonic mode (two-level atoms) in the photonic SRPT is played by an Fe<sup>3+</sup> magnon mode (Er<sup>3+</sup> spins). The absence of the diamagnetic term in the Fe<sup>3+</sup>-Er<sup>3+</sup> exchange coupling ensures that the no-go theorem does not apply. Ultrabroadband terahertz and gigahertz magnetospectroscopy experiments revealed the signatures of the SRPT in thermal equilibrium, a kink and a softening, respectively, of two spin-magnon hybridized modes at the critical point. Systems near this phase are expected to harbor large-scale squeezing, which will potentially provide a route to next-generation quantum technologies.
Authors
- Liang Luo (ORCID: https://orcid.org/0000-0002-6079-0214)
- Di Cheng (ORCID: https://orcid.org/0000-0002-2759-7797)
- Jacques Doumani (ORCID: https://orcid.org/0000-0002-2031-4918)
- Sohail Dasgupta
- Motoaki Bamba
- Shojiro Kimura (ORCID: https://orcid.org/0000-0002-1535-7307)
- Wanting Yang (ORCID: https://orcid.org/0000-0003-1736-4823)
- Kaden R. A. Hazzard (ORCID: https://orcid.org/0000-0003-2894-7274)
- J.-M. Park (ORCID: https://orcid.org/0000-0001-9936-7512)
- Xiaoxuan Ma (ORCID: https://orcid.org/0000-0002-4000-5733)
- Haotian Wei (ORCID: https://orcid.org/0000-0001-7684-2608)
- Henry O. Everitt (ORCID: https://orcid.org/0000-0002-8141-3768)
- Junichiro Kono (ORCID: https://orcid.org/0000-0002-4195-0577)
- Richard H. J. Kim (ORCID: https://orcid.org/0000-0002-4244-9653)
- Hiroyuki Nojiri (ORCID: https://orcid.org/0000-0002-9676-7710)
- Xinwei Li (ORCID: https://orcid.org/0000-0003-0555-2624)
- Jigang Wang (ORCID: https://orcid.org/0000-0002-6159-4119)
- Shixun Cao (ORCID: https://orcid.org/0000-0002-3915-2621)
- Dasom Kim (ORCID: https://orcid.org/0000-0002-2331-4526)
Institutions
- Shanghai University (CN)
- National University of Singapore (SG)
- Iowa State University (US)
- Yokohama National University (JP)
- Tohoku University (JP)
- United States Army Combat Capabilities Development Command (US)
- Ames National Laboratory (US)
- Rice University (US)
- University of California, Davis (US)
Publication Details
- Journal
- Science Advances
- Published
- 2025-04-04
- DOI
- https://doi.org/10.1126/sciadv.adt1691
- Citations
- 14
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 34.73