TY - JOUR

T1 - Nonlocal Galileons and self-acceleration

AU - Gabadadze, Gregory

AU - Yu, Siqing

N1 - Funding Information:
Both GG and SY were supported by NASA grant NNX12AF86G S06 and by NSF grant PHY-1316452. GG acknowledges a membership at the NYU-ECNU Joint Physics Research Institute in Shanghai.
Publisher Copyright:
© 2017 The Author(s)

PY - 2017/5/10

Y1 - 2017/5/10

N2 - A certain class of nonlocal theories eliminates an arbitrary cosmological constant (CC) from a universe that can be perceived as our world. Dark energy then cannot be explained by a CC; it could however be due to massive gravity. We calculate the new corrections, which originate from the nonlocal terms that eliminate the CC, to the decoupling limit Lagrangian of massive gravity. The new nonlocal terms also have internal field space Galilean symmetry and are referred here as “nonlocal Galileons.” We then study a self-accelerated solution and show that the new nonlocal terms change the perturbative stability analysis. In particular, small fluctuations are now stable and non-superluminal for some simple parameter choices, whereas for the same choices the pure massive gravity fluctuations are unstable. We also study stable spherically symmetric solutions on this background.

AB - A certain class of nonlocal theories eliminates an arbitrary cosmological constant (CC) from a universe that can be perceived as our world. Dark energy then cannot be explained by a CC; it could however be due to massive gravity. We calculate the new corrections, which originate from the nonlocal terms that eliminate the CC, to the decoupling limit Lagrangian of massive gravity. The new nonlocal terms also have internal field space Galilean symmetry and are referred here as “nonlocal Galileons.” We then study a self-accelerated solution and show that the new nonlocal terms change the perturbative stability analysis. In particular, small fluctuations are now stable and non-superluminal for some simple parameter choices, whereas for the same choices the pure massive gravity fluctuations are unstable. We also study stable spherically symmetric solutions on this background.

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U2 - 10.1016/j.physletb.2017.03.027

DO - 10.1016/j.physletb.2017.03.027

M3 - Article

AN - SCOPUS:85015636166

SN - 0370-2693

VL - 768

SP - 397

EP - 403

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

ER -