PreprintCC BY 4.0arXiv
Fresh Look at Shift Symmetric Modified Gravity
Abstract
Shift symmetric Horndeski gravity can be a simple, well posed theory with protection against quantum corrections. Overturning conventional thought that such a theory cannot cross the phantom divide (w=−1) we present both analytic and numerical proof that it can. We carry out a detailed dynamical systems analysis showing the evolution of ghost free and stable regions within the model family, identify the fixed point and dynamical attractor structure, and derive the interaction of the w=−1 curve with these phase space structures. This reveals two mechanisms for cosmologies crossing the phantom divide while preserving shift symmetry.
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BibTeX
@misc{calderon2026fresh,
title = {{Fresh Look at Shift Symmetric Modified Gravity}},
author = {Rodrigo Calderon and Eric V. Linder},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36063},
eprint = {2610.36063},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36063},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Fresh Look at Shift Symmetric Modified Gravity
AU - Rodrigo Calderon
AU - Eric V. Linder
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.36063
UR - https://arxiv.org/abs/2610.36063
AB - Shift symmetric Horndeski gravity can be a simple, well posed theory with protection against quantum corrections. Overturning conventional thought that such a theory cannot cross the phantom divide (w=−1) we present both analytic and numerical proof that it can. We carry out a detailed dynamical systems analysis showing the evolution of ghost free and stable regions within the model family, identify the fixed point and dynamical attractor structure, and derive the interaction of the w=−1 curve with these phase space structures. This reveals two mechanisms for cosmologies crossing the phantom divide while preserving shift symmetry.
ER -