[{"dataavailabilitystatement":"The data that support the findings of this article are openly\r\navailable [27 -  https://doi.org/10.7910/dvn/rqp3az], embargo periods may apply.","researchdata_availability":"yes","das_tickbox":"1","author":[{"first_name":"A.","last_name":"Liebman-Peláez","full_name":"Liebman-Peláez, A."},{"full_name":"Garratt, S. J.","last_name":"Garratt","first_name":"S. J."},{"last_name":"Sunko","first_name":"Veronika","id":"23cb1cf6-2c7a-11ef-91a4-f72fc19f20b3","full_name":"Sunko, Veronika","orcid":"0000-0003-2724-3523"},{"full_name":"Sun, Y.","last_name":"Sun","first_name":"Y."},{"last_name":"Soh","first_name":"J. R.","full_name":"Soh, J. R."},{"full_name":"Prabhakaran, D.","last_name":"Prabhakaran","first_name":"D."},{"last_name":"Boothroyd","first_name":"A. T.","full_name":"Boothroyd, A. T."},{"first_name":"J.","last_name":"Orenstein","full_name":"Orenstein, J."}],"article_number":"224401","publication_status":"published","intvolume":"       113","language":[{"iso":"eng"}],"issue":"22","acknowledgement":"We would like to thank Ehud Altman for helpful discussions. This research was primarily funded by the Quantum\r\nMaterials (KC2202) program under the U.S. Department of\r\nEnergy, Office of Science, Office of Basic Energy Sciences,\r\nMaterials Sciences and Engineering Division under Contract\r\nNo. DE-AC02-05CH11231, which supported the experimental and theoretical work at the Lawrence Berkeley National\r\nLaboratory and UC Berkeley. D.P. and A.T.B. would like to\r\nacknowledge the Engineering and Physical Sciences Research\r\nCouncil, UK and the Oxford- ShanghaiTech collaboration\r\nproject for financial support. J.O. received support from\r\nthe Gordon and Betty Moore Foundation’s EPiQS Initiative\r\nthrough Grant No. GBMF4537 to J.O. at UC Berkeley. V.S.\r\nis supported by the Miller Institute for Basic Research in\r\nScience, UC Berkeley. S.J.G. was supported by the Gordon\r\nand Betty Moore Foundation.","date_created":"2026-06-22T08:52:01Z","year":"2026","article_type":"original","date_published":"2026-06-01T00:00:00Z","volume":113,"month":"06","abstract":[{"text":"Magnets with isotropic easy-plane symmetry host Goldstone modes that can be leveraged for efficient\r\nspin transport. Here, we present a time-resolved optical polarimetry technique that allows us to detect and\r\ncharacterize such low-frequency modes, and use it to observe the Goldstone mode in the multi-Q broken helix\r\nphase of EuIn2As2. The strength of our technique comes from the ability to distinguish between nematic and\r\nmagnetization dynamics in order to yield information about the mode structure, in addition to its frequency. We\r\nfind that the nearly uniform spin precession characteristic of a Goldstone mode is realized only when a small\r\nmagnetic field is used to unpin the broken helix from local strain generated during crystal growth. In this regime,\r\nthe mode frequency scales linearly with the applied field due to the ground state C2z symmetry of the broken\r\nhelix. Our work shows how optical polarimetry can be used to study the Goldstone modes of complex magnets.","lang":"eng"}],"status":"public","quality_controlled":"1","publication_identifier":{"issn":["2469-9950"],"eissn":["2469-9969"]},"doi":"10.1103/b48p-kw5l","supplementarymaterial":"no","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa_version":"None","article_processing_charge":"No","type":"journal_article","extern":"1","publisher":"American Physical Society","citation":{"chicago":"Liebman-Peláez, A., S. J. Garratt, Veronika Sunko, Y. Sun, J. R. Soh, D. Prabhakaran, A. T. Boothroyd, and J. Orenstein. “Observation of a Goldstone Mode in the Broken Helix by Time-Resolved Optical Polarimetry.” <i>Physical Review B</i>. American Physical Society, 2026. <a href=\"https://doi.org/10.1103/b48p-kw5l\">https://doi.org/10.1103/b48p-kw5l</a>.","ista":"Liebman-Peláez A, Garratt SJ, Sunko V, Sun Y, Soh JR, Prabhakaran D, Boothroyd AT, Orenstein J. 2026. Observation of a Goldstone mode in the broken helix by time-resolved optical polarimetry. Physical Review B. 113(22), 224401.","short":"A. Liebman-Peláez, S.J. Garratt, V. Sunko, Y. Sun, J.R. Soh, D. Prabhakaran, A.T. Boothroyd, J. Orenstein, Physical Review B 113 (2026).","ieee":"A. Liebman-Peláez <i>et al.</i>, “Observation of a Goldstone mode in the broken helix by time-resolved optical polarimetry,” <i>Physical Review B</i>, vol. 113, no. 22. American Physical Society, 2026.","mla":"Liebman-Peláez, A., et al. “Observation of a Goldstone Mode in the Broken Helix by Time-Resolved Optical Polarimetry.” <i>Physical Review B</i>, vol. 113, no. 22, 224401, American Physical Society, 2026, doi:<a href=\"https://doi.org/10.1103/b48p-kw5l\">10.1103/b48p-kw5l</a>.","apa":"Liebman-Peláez, A., Garratt, S. J., Sunko, V., Sun, Y., Soh, J. R., Prabhakaran, D., … Orenstein, J. (2026). Observation of a Goldstone mode in the broken helix by time-resolved optical polarimetry. <i>Physical Review B</i>. American Physical Society. <a href=\"https://doi.org/10.1103/b48p-kw5l\">https://doi.org/10.1103/b48p-kw5l</a>","ama":"Liebman-Peláez A, Garratt SJ, Sunko V, et al. Observation of a Goldstone mode in the broken helix by time-resolved optical polarimetry. <i>Physical Review B</i>. 2026;113(22). doi:<a href=\"https://doi.org/10.1103/b48p-kw5l\">10.1103/b48p-kw5l</a>"},"publication":"Physical Review B","_id":"22116","title":"Observation of a Goldstone mode in the broken helix by time-resolved optical polarimetry","OA_type":"closed access","date_updated":"2026-06-24T09:49:27Z","day":"01"}]