The zoo plot meets the swampland : mutual (in)consistency of single-field inflation, string conjectures, and cosmological data

• We consider single-field inflation in light of string-motivated 'swampland' conjectures suggesting that effective scalar field theories with a consistent UV completion must have field excursion Delta(phi) less than or similar to M-Pl, in combination with a sufficiently steep potential, MPlV phi/V greater than or similar to O(1). Here, we show that the swampland conjectures are inconsistent with existing observational constraints on single-field inflation. Focusing on the observationally favoured class of concave potentials, we map the allowed swampland region onto the n(S)-r 'zoo plot' of inflationary models, and find that consistency with the Planck satellite and BICEP2/Keck Array requires MPlV phi/V less than or similar to 0.1 and -0.02 less than or similar to M-Pl(2)/V-phi phi < 0, in strong tension with swampland conjectures. Extension to non-canonical models such as DBI Inflation does not significantly weaken the bound.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Keyword

cosmic inflation

cosmic microwave background

swampland conjectures

Quantum Science & Technology

Publication and Content Type

ref (subject category)

art (subject category)