19 May 2022 Thu 10 am

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I will provide the historical review of magneto-roton excitation, which is the gapped neutral excitation in the Lowest Landau Level. The magneto-roton mode has spin-2 and is a massive graviton mode in 2+1D [1]. This spin-2 mode plays a central role in the physics of FQH. In the current literature, the spin-2 mode of Jain’s sequences near filling fraction 1/2 can be thought of as the shear deformation of the composite fermion Fermi surface [2]. In this talk, I will show that there will be an extra massive graviton mode for Jain’s sequences near filling fraction 1/4 [3]. The additional graviton was proposed in our recent work on the Dirac composite fermion theory of general Jain’s sequences to satisfy the Haldane bound of the static structure factor. The extra mode was confirmed numerically recently with the guidance of FQH sum rules [4]. I will briefly discuss our physical interpretation of the new massive graviton mode.

[1] Siavash Golkar, Dung X. Nguyen and Dam T. Son JHEP 021, 01 (2016)

[2] DX Nguyen, A Gromov, DT Son, Physical Review B 97 (19), 195103 (2018)

[3] DX Nguyen, DT Son, Physical Review Research 3 (3), 033217 (2021)

[4] DX Nguyen, F. D. Haldane, Edward Rezayi, Dam T. Son, and Kun Yang (Arxiv:2111.10593)

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