Spontaneous symmetry breaking as a late-time trigger for interacting dark energy

Title

Spontaneous symmetry breaking as a late-time trigger for interacting dark energy

Creator

Mv, Pradosh Keshav; Kavya, N.S.; Arun, Kenath

Description

Persistent tensions in the Hubble constant (H 0) and the matter clustering parameter (S 8) motivate late-time new physics that suppresses structure growth while remaining compatible with current background constraints of the ?CDM model. We study a new class of dark sector dynamics in which a scalar dark energy (DE) field, governed by a ?2-symmetric quartic potential, interacts with dark matter (DM) through Yukawa and portal couplings. When the matter density drops below a critical threshold, a cosmological spontaneous symmetry breaking (SSB) mechanism generates a time-dependent vacuum expectation value v(a) and activates an effective coupling ?(a). This produces a symmetric phase (a ? ac) identical to ?CDM at early times, and a broken phase (a > ac) in which ?(a) > 0 transfers energy from DM to DE, suppressing the linear growth of structure. We confront this framework with RSD, BAO, CC, and Pantheon+SH0ES supernova data, jointly with compressed Planck distance priors, comparing a fixed ?CDM background to a self-consistent coupled scalar evolution. The RSD-only analysis shows a pronounced shift: the dynamical background yields ?m ? 0.31 0.10 and ? 80 ? 0.59 0.01, with a higher matter density but a substantially lower growth amplitude compared to the fixed background case ?m ? 0.20 0.09 and ? 80 ? 0.75 0.05. In the full joint fit, conditioned on geometric distance information, the inferred parameters are ?m = 0.29 0.01, H 0 = 69.7 0.6 km s-1 Mpc-1, and ? 80 = 0.78 0.01. These results demonstrate that a late-time, SSB-activated interaction can efficiently dampen structure growth and potentially alleviate the S 8 tension. In growth-dominated analyses such as RSD-only constraints, the inferred value of H 0 is only weakly affected by the coupling. However, in joint analyses including strong external distance calibrations, the inferred H 0 becomes sensitive to dataset choice and to whether the background expansion is treated self-consistently. 2026 IOP Publishing Ltd and Sissa Medialab. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the https://publishingsupport.iopscience.iop.org/iop-standard/v1.

Source

Journal of Cosmology and Astroparticle Physics;Volume;2026;Issue;5;

Date

01-01-2026

Publisher

Institute of Physics

Subject

Cosmological perturbation theory in GR and beyond; dark energy theory; dark matter theory; supernova type Ia - standard candles

Coverage

Mv P.K., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India; Kavya N.S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Bengaluru, 560029, India; Arun K., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India

Rights

Restricted Access; Hardcopy may be available in the library

Relation

ISSN: 14757516;

Format

online

Language

English

Type

Article

Identifier

https://doi.org/10.1088/1475-7516/2026/05/019

https://www.scopus.com/pages/publications/105038402562?origin=resultslist