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The possibility that the $H_0$ tension is a sign of a physics beyond the $\Lambda$CDM model is one of the most exciting possibilities in modern cosmology. The challenge of solving this problem is complicated by several factors, including…
The basic cosmological distances are linked by the Etherington cosmic distance duality relation, $\eta (z) = D_{L}(z)(1+z)^{-2}/D_{A}(z) \equiv 1$, where $D_{L}$ and $D_{A}$ are, respectively, the luminosity and angular diameter distances.…
Measurements of the $H_0$ and $\sigma_8$ parameters within the standard cosmological model recently highlighted significant statistical tensions between the cosmic microwave background and low-redshift probes, such as local distance ladder,…
In the effort to define the main features a successful solution to the Hubble tension should have, growing evidence has emerged pointing to the need for models able to modify the expansion (and possibly thermal) history of the universe both…
Consistent observations indicate that some of the important cosmological parameters measured through the local observations are in huge tension with their measurements from the global observations (within the minimal $\Lambda$CDM…
We consider the problem of sufficient dimensionality reduction (SDR), where the high-dimensional observation is transformed to a low-dimensional sub-space in which the information of the observations regarding the label variable is…
The well-known tensions on the cosmological parameters $H_0$ and $\sigma_8$ within the $\Lambda$CDM cosmology shown by the Planck-CMB and LSS data are possibly due to the systematics in the data or our ignorance of some new physics beyond…
The Hubble tension, characterized by discrepant measurements of the Hubble constant from early and late universe probes, remains one of the most significant challenges in cosmology. Building upon our previous analysis of individual…
In recent years discrepancies have emerged in measurements of the present-day rate of expansion of the universe $H_0$ and in estimates of the clustering of matter $S_8$. Using the most recent cosmological observations we reexamine a novel…
There has been a significant interest in modifications of the standard $\Lambda$ Cold Dark Matter ($\Lambda$CDM) cosmological model prompted by tensions between certain datasets, most notably the Hubble tension. The late-time modifications…
We analyze the properties that any late-time modification of the $\Lambda$CDM expansion history must have in order to consistently solve both the $H_0$ and the $\sigma_8$ tensions. Taking a model-independent approach, we obtain a set of…
We present a model describing the dark sector (DS) featured by two interactions remaining efficient until late times in the matter-dominated era after recombination: the interaction among dark radiations (DR), and the interaction between a…
Models of a dark radiation sector with a mass threshold (WZDR+) have proved to be an appealing alternative to $\Lambda$CDM. These models provide simple comparison models, grounded in well-understood particle physics and with limited…
Several cosmological tensions have emerged in light of recent data, most notably in the inferences of the parameters $H_0$ and $\sigma_8$. We explore the possibility of alleviating both these tensions {\it simultaneously} by means of the…
Moment-based distributionally robust optimization (DRO) provides an optimization framework to integrate statistical information with traditional optimization approaches. Under this framework, one assumes that the underlying joint…
The '$S_8$ tension' is a longstanding discrepancy between the cosmic microwave background (CMB) and weak gravitational lensing determination of the amplitude of matter fluctuations, parametrized as $S_8\equiv\sigma_8(\Omega_m/0.3)^{0.5}$,…
We constrain and compare the $w_{0}w_{a}$CDM dynamical dark energy model and three $f(R)$ modified gravity models using the current cosmological distance measurements, including 112 high-quality localized FRBs, BAO measurements from the…
Based on tensions between the early and late time cosmology, we proposed a double valued cosmological constant which could undergo a phase transition in its history. It is named "double-$\Lambda$ Cold Dark Matter": $\Lambda\Lambda$CDM. An…
Addressing the discrepancy between the late and early time measurements of the Hubble parameter, $H_0$, and the so-called $S_8$ parameter has been a challenge in precision cosmology. Several models are present to address these tensions, but…
In this study, we investigate the $w$CDM dynamical dark energy model with spatial curvature utilizing the recently released DESI Collaboration data (DR1 and DR2) in conjunction with other observational probes such as BBN, Observational…