TY  - JOUR
AU  - Berbig, M.
PY  - 2025
DA  - 2025//
TI  - Kick it like DESI: PNGB quintessence with a dynamically generated initial velocity
T2  - J. Cosmol. Astropart. Phys.
JO  - Journal of Cosmology and Astroparticle Physics
SP  - 015
EP  - 46pp
VL  - 03
IS  - 3
PB  - IOP Publishing Ltd
KW  - axions
KW  - baryon acoustic oscillations
KW  - dark energy theory
KW  - particle physics- cosmology connection
AB  - Motivated by the hint for time-dependent dynamical dark energy from an analysis of the DESI Baryon Accoustic Oscillation (BAO) data together with information from the Cosmic Microwave Background (CMB) and Supernovae (SN), we relax the assumption of a vanishing initial velocity for a quintessence field. In particular we focus on pseudo-NambuGoldstone-Boson (PNGB) quintessence in the form of an axion like particle, that can arise as the phase of a complex scalar and could possess derivative couplings to fermions or topological couplings to abelian gauge fields, without upsetting the necessary flatness of its potential. We discuss mechanisms from the aforementioned interactions for sourcing an initial axion field velocity theta(center dot)i at redshifts 3 <= z <= 10, that will "kick" it into motion. Driven by this initial velocity the axion will first roll up in its potential, similar to "freezing" dark energy. After it has reached the pinnacle of its trajectory, it will start to roll down, and behave as "thawing" quintessence. As a proof of concept we undertake a combined fit to BAO, SN and CMB data at the background level. We find that a scenario with theta(center dot)i = O (1) ma, where ma is the axion mass, is slightly preferred over both Lambda CDM and the conventional "thawing" quintessence with theta(center dot)i = 0. The best fit points for this case exhibit transplanckian decay constants and very flat potentials, which both are in tension with conjectures from string theory.
SN  - 1475-7516
UR  - https://arxiv.org/abs/2412.07418
UR  - https://doi.org/10.1088/1475-7516/2025/03/015
DO  - 10.1088/1475-7516/2025/03/015
LA  - English
N1  - WOS:001440806800004
ID  - Berbig2025
ER  -