Theoretical Physics Department Seminars Seminars usually occur in the Theoretical Physics Division of INR, 27.10.25
Seminar, Department of Theoretical Physics, INR RAS
27th of October, 2025, 15:30 Moscow time
To be held in conference-hall, INR RAS (Pitomnik)
(with online participation via Yandex-Telemost)
Mauricio Valencia-Villegas (ITMP MSU & INR RAS)
Stability and speed tests on Scalar--Vector--Tensor theories
(based on materials of PhD thesis)
Please, find an annotation below
https://telemost.yandex.ru/j/70882270756130
Abstract:
Scalar--Tensor theories are extensively used to build interesting
cosmological solutions for the early and late universe. However, they
face two major challenges: most predict a speed of gravitational waves
(GW) different from the speed of light -- which is in tension with the
GW event GW170817-- and they are subject to No-Go theorems that
question their stability.
In this talk, we show a set of Scalar-Vector couplings for
generalisations of Horndeski theory, such as GLPV, which enforce the
propagation of vector modes at the same speed as GW. This offers a
viable path to reconcile these theories with the constraints from the
event GW170817.
Regarding the stability issues, we first present a No-Go theorem that
holds in a subset of Horndeski theories with torsion. Then, we show
that in the most general Horndeski-Cartan theories such a no-go
theorem cannot be formulated.
27th of October, 2025, 15:30 Moscow time
To be held in conference-hall, INR RAS (Pitomnik)
(with online participation via Yandex-Telemost)
Mauricio Valencia-Villegas (ITMP MSU & INR RAS)
Stability and speed tests on Scalar--Vector--Tensor theories
(based on materials of PhD thesis)
Please, find an annotation below
https://telemost.yandex.ru/j/70882270756130
Abstract:
Scalar--Tensor theories are extensively used to build interesting
cosmological solutions for the early and late universe. However, they
face two major challenges: most predict a speed of gravitational waves
(GW) different from the speed of light -- which is in tension with the
GW event GW170817-- and they are subject to No-Go theorems that
question their stability.
In this talk, we show a set of Scalar-Vector couplings for
generalisations of Horndeski theory, such as GLPV, which enforce the
propagation of vector modes at the same speed as GW. This offers a
viable path to reconcile these theories with the constraints from the
event GW170817.
Regarding the stability issues, we first present a No-Go theorem that
holds in a subset of Horndeski theories with torsion. Then, we show
that in the most general Horndeski-Cartan theories such a no-go
theorem cannot be formulated.