423 citations · 1.8k across the 30 of their papers we have counts for
7 papers · 1 filter
Is Trans-Planckian Censorship a Swampland Conjecture?
Ryo Saito, Satoshi Shirai, Masahito Yamazaki
During an accelerated expansion of the Universe, quantum fluctuations of sub-Planckian size can be stretched outside the horizon and be regarded effectively classical. Recently, it…
Phenomenological Consequences of the Refined Swampland Conjecture
Hajime Fukuda, Ryo Saito, Satoshi Shirai +1
We discuss phenomenological consequences of the recently-introduced refinements of the de Sitter swampland conjecture. The conjecture constraints the first and the second derivativ…
Heavy Particle Signatures in Cosmological Correlation Functions with Tensor Modes
Ryo Saito, Takahiro Kubota
We explore the possibility to make use of cosmological data to look for signatures of unknown heavy particles whose masses are on the order of the Hubble parameter during the time…
Cosmological correlation functions including a massive scalar field and an arbitrary number of soft-gravitons
Ryo Saito
We study the imprint of a massive scalar particle on cosmological correlation functions, and suggest the way to determine the mass of the newly introduced particle, which is expect…
Combined features in the primordial spectra induced by a sudden turn in two-field DBI inflation
Shuntaro Mizuno, Ryo Saito, David Langlois
We investigate the features generated by a sharp turn along the inflationary trajectory in a two-field model of Dirac-Born-Infeld inflation, where one of the fields is heavy. Disti…
Coleman-de Luccia instanton in dRGT massive gravity
Ying-li Zhang, Ryo Saito, Dong-han Yeom +1
We study the Coleman-de Luccia (CDL) instanton characterizing the tunneling from a false vacuum to the true vacuum in a semi-classical way in dRGT (deRham-Gabadadze-Tolley) massive…
Hawking-Moss instanton in nonlinear massive gravity
Ying-li Zhang, Ryo Saito, Misao Sasaki
As a first step toward understanding a lanscape of vacua in a theory of non-linear massive gravity, we consider a landscape of a single scalar field and study tunneling between a p…