[[UTAPwiki/セミナー/初期宇宙・相対論速報]] * On Lorentz-invariant (bi-)spin-2 theories [#w27d73bf] ** Daisuke Yamauchi [#a424effa] In this talk, I will discuss the Lorentz-invariant massless and massive spin-2 theories in flat spacetime. Starting from the most general action of a rank-2 symmetric tensor field whose Lagrangian contains up to quadratic in first derivatives of a field, I classify ghost-free theories based on the number of degree-of-freedom and constraint structures. I also discuss the possible extension to the ghost-free bi-spin-2 theories. |