arXiv subjects

Sara Krieg

Publications and source records attributed to Sara Krieg.

5 recordsLinked to original sources

arXiv2025

Addendum: Fitting the DESI BAO Data with Dark Energy Driven by the Cohen-Kaplan-Nelson Bound

Motivated by the recent Year-2 data release of the DESI collaboration, we update our results on time-varying dark energy models driven by the Cohen-Kaplan-Nelson bound. The previously found preference of time-dependent dark energy models compared to $\Lambda$CDM is further strengthend by the new data release. For our particular models, we find that this preference increases up to $\approx 2.6\,\sigma$ depending on the used supernova dataset.

astro-ph.CO↗

arXiv2024

Dark Energy Driven by the Cohen-Kaplan-Nelson Bound

In this work, we confront the bound on an ultraviolet cutoff (UV) of a quantum field theory (QFT) proposed by Cohen, Kaplan, and Nelson (CKN) with the latest results of the Dark Energy Spectroscopic Instrument (DESI). The former relates the UV cutoff with an infrared (IR) cutoff of the theory by excluding all states describing a black hole. Identifying now the IR cutoff with the Hubble horizon yields a time-varying contribution of the vacuum energy to the dark energy density of the universe. At the same time the DESI results in combination with other cosmological data point towards a preference of time-varying dark energy models over $\Lambda$CDM.

astro-ph.CO↗

arXiv2024

Potential of Neutrino Telescopes to Detect Quantum Gravity-Induced Decoherence in the Presence of Dark Fermions

We assess the potential of neutrino telescopes to discover quantum-gravity-induced decoherence effects modeled in the open-quantum system framework and with arbitrary numbers of active and dark fermion generations, such as particle dark matter or sterile neutrinos. The expected damping of neutrino flavor oscillation probabilities as a function of energy and propagation length thus encodes information about quantum gravity effects and the fermion generation multiplicity in the dark sector. We employ a public Monte-Carlo dataset provided by the IceCube Collaboration to model the detector response and estimate the sensitivity of IceCube to oscillation effects in atmospheric neutrinos induced by the presented model. Our findings confirm the potential of very-large-volume neutrino telescopes to test this class of models and indicate higher sensitivities for increasing numbers of dark fermions.

hep-ph↗

arXiv2024

Fitting the DESI BAO Data with Dark Energy Driven by the Cohen-Kaplan-Nelson Bound

Gravity constrains the range of validity of quantum field theory. As has been pointed out by Cohen, Kaplan, and Nelson (CKN), such effects lead to interdependent ultraviolet (UV) and infrared (IR) cutoffs that may stabilize the dark energy of the universe against quantum corrections, if the IR cutoff is set by the Hubble horizon. As a consequence of the cosmic expansion, this argument implies a time-dependent dark energy density. In this paper we confront this idea with recent data from DESI BAO, Hubble and supernova measurements. We find that the CKN model provides a better fit to the data than the $\Lambda$CDM model and can compete with other models of time-dependent dark energy that have been studied so far.

astro-ph.CO↗

arXiv2024

Neutrino Oscillations as a Gravitational Wave Detector?

Gravitational waves (GWs) can alter the neutrino propagation distance and thus affect neutrino oscillations. This can result in a complete disappearance of the oscillatory behavior that competes with other sources of neutrino decoherence. We develop a set of criteria that determines under which conditions neutrino oscillations are sensitive to this effect. We find that current or near future neutrino oscillation experiments are not sufficiently sensitive to coherent GW signals but may probe the stochastic gravitational wave background if the energy resolution improves drastically by several orders of magnitude.

hep-ph↗