![[PukiWiki]](image/pukiwiki.png "[PukiWiki]")
[[UTAPwiki/セミナー/初期宇宙・相対論速報]] * [#abbd60a4] * Cosmological superfluids and phonons [#z8f6a28e] **Kohei Kamada [#nc1e4e3a] **Kohei Kamada [#wd31e2cf] Spontaneous space-time symmetry breaking is now known to be a key to explore cosmology such as inflation, dark energy, and dark matter. In this talk, I will introduce the way to understand the cosmological perturbation as the Nambu-Goldstone mode of the space-time symmetry breaking and to construct their effective field theory, following the references [1,2]. I start from the brief introduction of the coset construction and inverse Higgs constraints, Then I discuss the way to understand the perturbation to be the phonons in superfluids, which is related to e.g., DBI and cuscuton and construct their effective Lagrangian. If time allows, I will also discuss the appearance of other (unconventional) types of phonons. References [1] Enrico Pajer, David Stefanyszyn, "Symmetric Superfluids", arXiv:1812.05133 [2] Tanguy Grall, Sadra Jazayeri, David Stefanyszyn, "The Cosmological Phonon: Symmetries and Amplitudes on Sub-Horizon Scales”, arXiv:2005.12937 [3] Sidney R. Coleman, J. Wess, Bruno Zumino, “Structure of phenomenological Lagrangians. 1“, Phys.Rev. 177 (1969) 2239-2247 [4] Curtis G. Jr. Callan, Sidney R. Coleman, J. Wess, Bruno Zumino, “Structure of phenomenological Lagrangians. 1“, Phys.Rev. 177 (1969) 2247-2250 [5] E.A. Ivanov, V.I. Ogievetsky, "The Inverse Higgs Phenomenon in Nonlinear Realizations”, Teor.Mat.Fiz. 25 (1975) 164-177, [6] D.T. Son, “Low-energy quantum effective action for relativistic superfluids”, hep-ph/0204199 |