Has the equivalent of the Higgs boson in condensed matter been detected? I know that the Higgs mechanism has some analogous models to theories that describe the behaviour of quasiparticles in condensed matter, like in superconductivity and other spontaneous symmetry breaking byproducts.
I tried to ask a few experimental researchers in the field if the equivalent of the "Higgs boson" (not Higgs mechanism) in those systems has ever been detected. But I have received mixed responses, some saying yes, some discarding the idea.
So I ask here, has there ever been a detection of a condensed matter equivalent Higgs quasiparticle boson or collective excitations of their equivalent "Higgs field"? If no, why? If yes, how close is the analogy to the [vacuum] Higgs boson?
 A: In superconductors there's an equivalent of the Higgs boson called the Higgs mode. There's a rather recent review article that discusses the experimental situation in some detail, Ryo Shimano, and Naoto Tsuji, "Higgs Mode in Superconductors," Annual Reviews in Condensed Matter Physics 11, pp. 103-124 (2020) (alternate arXiv link). My reading is that there have been longstanding experimental difficulties, and some conceptual ones distinguishing the Higgs mode from charge density wave states, but that both have been resolved recently, and that the Higgs mode has been seen clearly in materials like NbN. However, I'm in no way an expert in this field, so the experimentalists you've been talking to may have some well-founded doubts or criticisms.

There have also been reported observations of Higgs modes in cold atoms and magnetic systems:

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*Manuel Endres, Takeshi Fukuhara, David Pekker, Marc Cheneau, Peter Schauβ, Christian Gross, Eugene Demler, Stefan Kuhr, and Immanuel Bloch, "The ‘Higgs’ amplitude mode at the two-dimensional superfluid/Mott insulator transition," Nature 487, pp. 454–458 (2012).

*A. Jain, M. Krautloher, J. Porras, G. H. Ryu, D. P. Chen, D. L. Abernathy, J. T. Park, A. Ivanov, J. Chaloupka, G. Khaliullin, B. Keimer, and B. J. Kim, "Higgs mode and its decay in a two-dimensional antiferromagnet," Nature Physics 13, pp. 633-637 (2017).

*Tao Hong, Masashige Matsumoto, Yiming Qiu, Wangchun Chen, Thomas R. Gentile, Shannon Watson, Firas F. Awwadi, Mark M. Turnbull, Sachith E. Dissanayake, Harish Agrawal, Rasmus Toft-Petersen, Bastian Klemke, Kris Coester, Kai P. Schmidt, and David A. Tennant, "Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point," Nature Physics 13, pp. 638–642 (2017).
