Bound Dark Energy: Particle Physics model in alignment with recent DESI cosmological measurements

TL;DR

This work presents observational constraints on Bound Dark Energy Cold Dark Matter (BDE-CDM), a particle-physics motivated model in which dark energy arises from a light dark meson in a supersymmetric SU(3) gauge sector with N_f=6. Using DESI DR2 BAO, Planck CMB, and multiple Type Ia SN compilations, the authors fix the condensation scale $\Lambda_c$ and transition epoch $a_c$ via gauge unification, yielding a dynamical equation of state that stays above $-1$ (approximately $w_0\approx-0.93$ with $w_a\approx-0.81$). They find strong evidence for dynamical dark energy over $\Lambda$CDM, with tight $w_0$-$w_a$ constraints and a distinctive 25% enhancement in the matter power spectrum at $k\approx4.3\,h\mathrm{Mpc}^{-1}$, along with robust stability across SN datasets. The analysis demonstrates that a theoretically grounded DE mechanism can address DESI’s preference for dynamics while maintaining consistency with CMB and BAO observations, providing a concrete link between particle physics and cosmology. These results position BDE-CDM as a testable, non-phantom alternative to the cosmological constant, with clear predictions for upcoming large-scale structure surveys.

Abstract

We present observational constraints on the Bound Dark Energy Cold Dark Matter (BDE-CDM) model using DESI DR2 baryon acoustic oscillation measurements combined with Planck CMB data and Type Ia supernovae compilations (PantheonPlus, Union3, DESY5). In BDE-CDM, dark energy originates from the lightest meson field within a supersymmetric SU(3) dark gauge group with $N_f = 6$ flavors, governed by an inverse power-law potential $V(φ) = Λ_{c}^{4+2/3} φ^{-2/3}$. Unlike $Λ$CDM and $w_0w_a$CDM, the dark energy sector contains no free parameters -- the condensation scale $Λ_c$ and transition epoch $a_c$ are determined by gauge coupling unification constraints. The equation of state evolves from relativistic behavior ($w = 1/3$) before condensation through a kinetic-dominated stiff phase ($w \simeq 1$), approaching $w_0 = -0.9298 \pm 0.0003$ at present, with $w > -1$ maintained throughout cosmic history, avoiding phantom-regime instabilities. We obtain $Λ_{c} = 43.93 \pm 0.13$~eV and $a_c = (2.489 \pm 0.007) \times 10^{-6}$, consistent with theoretical predictions. The $w_0$-$w_a$ confidence contours are approximately 10,000 times smaller than those of $w_0w_a$CDM while achieving comparable fits, and remain stable across different supernova datasets. Statistical analysis yields $Δ\mathrm{DIC} = -6.77$ and $Δ\mathrm{AIC} = -8.97$ relative to $Λ$CDM for BAO+DESY5, constituting strong evidence favoring BDE-CDM model. The model predicts distinctive signatures including 25\% enhancement in the matter power spectrum at $k \approx 4.3\,h\,\mathrm{Mpc}^{-1}$. These results establish BDE-CDM as a theoretically motivated framework that successfully addresses the DESI-observed preference for dynamical dark energy while connecting particle physics with cosmological observations.

Figures (17)

• Figure 1: EoS $w(z)=P/\rho$ as function of redshift and scale factor in the framework of BDE-CDM, $\Lambda$CDM and $w_0w_a$CDM models from the joint analysis of BAO+CMB+DESY5 (left column), BAO+CMB+Union3 (middle column) and BAO+CMB+PantheonPlus (right column). In the first row, the evolution of $w(a)$ is exhibited as a function of scale factor $a$, from $a=1\times10^{-6}$ to present time $a_{0}=1$. In the second row, it shown the evolution of $w(z)$ in terms of redshift, in the redshift range $0<z<3$. In the third row, a closer look in the evolution of $w(z)$ in BDE-CDM model. The dotted and solid grey lines shows the scale factor $a_{c}$, $a_{eq}$, $a_{\mathrm{DE}}(z_{\mathrm{DE}})$ corresponding to the transition scale, radiation-matter equality and matter-dark energy equality.
• Figure 2: Left panel:$68\%$ and $95\%$ marginalized posterior constraints in the $w_0$-$w_a$ plane for the flat $w_0w_a$CDM model, from DESI DR2 BAO combined with CMB and each of the PantheonPlus Scolnic_2022, Union3 Rubin_2025, and DESY5 Abbott_2024 SNe-Ia datasets. Middle panel:$68\%$ add $95\%$ marginalized posterior constraints in the $w_0$-$w_a$ plane for the BDE-CDM model, exhibiting no shifting in the contour areas across the three data combinations considered. Each of these combinations sets a range of $w_0$ and $w_a$ of $-0.928<w_0<-0.931$, $-0.80<w_0<-0.83$, respectively. Right panel:$68\%$ and $95\%$ marginalized posterior constraints comparative in the $w_0$-$w_a$ plane between BDE-CDM and $w_0w_a$CDM models, selecting the BAO+CMB+DESY5 data combination as a reference.
• Figure 3: Normalized dark energy density, $f_{\mathrm{DE}}(z)\equiv \rho_{\mathrm{DE}}(z)/\rho_{\mathrm{DE}}(0)$, as a function of redshift in the framework of BDE-CDM and $w_0w_a$CDM model from the data combination BAO+CMB+Union3. The dotted vertical line indicate the dark energy-matter equality redshift. The horizontal dashed black line represents $\Lambda$CDM.
• Figure 4: Evolution of the $\mathcal{O}m(z)$ diagnostic and deceleration parameter, $q(z)$, as a function of redshift for the BDE-CDM, $\Lambda$CDM and $w_0w_a$CDM models. The solid color lines of each model correspond to the median, $68$, and $95\%$ confidence levels obtained from the BAO+CMB+Union3 and BAO+CMB+DESY5 combinations. The blue dotted vertical lines indicate the dark energy-matter equality ($z_{\mathrm{DE}}$) redshift.
• Figure 5: Marginalized distributions and $68\%$ and $95\%$ confidence contours of some cosmological key parameters for the BDE-CDM (green), $\Lambda$CDM (aqua blue), and $w_0w_a$CDM (navy blue) models from the combination of DESI DR2 BAO tr6ykpc6, CMB refId0, and PantheonPlus Scolnic_2022.