90 citations · 276 across the 9 of their papers we have counts for
Showing hep-thShow all
3 papers · 1 filter
hep-th2023★ 4 cited
Boundary Conditions for Constraint Systems in Variational Principle
Keisuke Izumi, Keigo Shimada, Kyosuke Tomonari +1
We show the well-posed variational principle in constraint systems. In a naive procedure of the variational principle with constraints, the proper number of boundary conditions doe…
hep-th2020★ 34 cited
Cosmological Perturbations in Palatini Formalism
Mio Kubota, Kin-ya Oda, Keigo Shimada +1
We investigate cosmological perturbations of scalar-tensor theories in Palatini formalism. First we introduce an action where the Ricci scalar is conformally coupled to a function…
hep-th2019★ 56 cited
Scalar-metric-affine theories: Can we get ghost-free theories from symmetry?
Katsuki Aoki, Keigo Shimada
We reveal the existence of a certain hidden symmetry in general ghost-free scalar-tensor theories which can only be seen when generalizing the geometry of the spacetime from Rieman…