Probing Dark Energy Microphysics with kSZ Tomography
Year: 2026
Type: article
Abstract: The accelerated expansion of the Universe is well established by geometric probes, yet its physical origin remains poorly understood. Most constraints on dark energy arise from background observables – supernovae, baryon acoustic oscillations, and the cosmic microwave background – which mainly test the homogeneous expansion history. To move beyond this limitation, we examine how kinetic Sunyaev–Zel’dovich (kSZ) tomography, combined with galaxy clustering, can probe perturbative effects of dark energy and improve constraints on its background parameters. Using a Fisher-matrix analysis of the joint power spectra for LSST- and CMB-S4-like surveys, we quantify the additional information kSZ tomography contributes to dark-energy inference. Including kSZ data tightens constraints on w 0 by 15 % and on w a by 32 %, with parameter degeneracies distinct from those of geometric probes. We also assess the detectability of dark-energy perturbations through a two-parameter model, finding that for canonical sound speed ( c s = 1 ) the effects are sub-percent and confined to horizon scales, while smaller sound speeds shift them to accessible k -ranges. Near-term kSZ measurements will primarily serve to test the consistency between background and perturbative signals, while future low-noise, high-resolution surveys may begin to uncover the microphysical properties of dark energy.
Source: The Open Journal of Astrophysics
DOI: 10.33232/001c.162336
Authors: Julius Adolff, Selim Hotinli, Neal Dalal
Institution: ORCID
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4416156673
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