Spin-2 fields and the weak gravity conjecture
File(s)PhysRevD.100.104033.pdf (330.46 KB)
Published version
Author(s)
de Rham, Claudia
Heisenberg, Lavinia
Tolley, Andrew J
Type
Journal Article
Abstract
Recently, it has been argued that application of the weak gravity conjecture (WGC) to spin-2 fields implies a universal upper bound on the cutoff of the effective theory for a single spin-2 field. We point out here that these arguments are largely spurious, because of the absence of states carrying spin-2 Stückelberg
U
(
1
)
charge, and because of incorrect scaling assumptions. Known examples such as Kaluza-Klein theory that respect the usual WGC do so because of the existence of a genuine
U
(
1
)
field under which states are charged, as in the case of the Stückelberg formulation of spin-1 theories, for which there is an unambiguously defined
U
(
1
)
charge. Theories of bigravity naturally satisfy a naive formulation of the WGC,
M
W
<
M
Pl
, since the force of the massless graviton is always weaker than the massive spin-2 modes. It also follows that theories of massive gravity trivially satisfies this form of the WGC. We also point out that the identification of a massive spin-2 state in a truncated higher derivative theory, such as Einstein-Weyl-squared or its supergravity extension, bears no relationship with massive spin-2 states in the UV completion, contrary to previous statements in the literature. We also discuss the conjecture from a swampland perspective and show how the emergence of a universal upper bound on the cutoff relies on strong assumptions on the scale of the couplings between the spin-2 and other fields, an assumption which is known to be violated in explicit examples.
U
(
1
)
charge, and because of incorrect scaling assumptions. Known examples such as Kaluza-Klein theory that respect the usual WGC do so because of the existence of a genuine
U
(
1
)
field under which states are charged, as in the case of the Stückelberg formulation of spin-1 theories, for which there is an unambiguously defined
U
(
1
)
charge. Theories of bigravity naturally satisfy a naive formulation of the WGC,
M
W
<
M
Pl
, since the force of the massless graviton is always weaker than the massive spin-2 modes. It also follows that theories of massive gravity trivially satisfies this form of the WGC. We also point out that the identification of a massive spin-2 state in a truncated higher derivative theory, such as Einstein-Weyl-squared or its supergravity extension, bears no relationship with massive spin-2 states in the UV completion, contrary to previous statements in the literature. We also discuss the conjecture from a swampland perspective and show how the emergence of a universal upper bound on the cutoff relies on strong assumptions on the scale of the couplings between the spin-2 and other fields, an assumption which is known to be violated in explicit examples.
Date Issued
2019-11-18
Date Acceptance
2019-11-01
Citation
Physical Review D: Particles, Fields, Gravitation and Cosmology, 2019, 100 (10), pp.1-20
ISSN
1550-2368
Publisher
American Physical Society
Start Page
1
End Page
20
Journal / Book Title
Physical Review D: Particles, Fields, Gravitation and Cosmology
Volume
100
Issue
10
Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/). Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Sponsor
Science and Technology Facilities Council (STFC)
The Royal Society
The Royal Society
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000496926600007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
ST/P000762/1
PHTH_P62062
PHTH_P62062
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Physics, Particles & Fields
Physics
VELTMAN-ZAKHAROV DISCONTINUITY
LIMIT
Publication Status
Published
Article Number
ARTN 104033
Date Publish Online
2019-11-18