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Although it is well known that the bulk of dark matter (DM) has to be cold, the existence of an additional sub-dominant, hot species remains a valid possibility. In this paper we investigate the potential of the cosmic shear power spectrum to constrain such a mixed (hot plus cold) DM scenario with two additional free parameters, the hot-to-total DM fraction ($f_{\rm hdm}$) and the thermal mass of the hot component ($m_{\rm hdm}$). Running a Bayesian inference analysis for both the Kilo-Degree Survey cosmic shear data (KiDS) as well as the Cosmic Microwave Background (CMB) temperature and polarisation data from Planck, we derive new constraints for the mixed DM scenario. We find a 95 per cent confidence limit of $f_{\rm hdm}<0.08$ for a very hot species of $m_{\rm hdm}\leq20$ eV. This constraint is weakened to $f_{\rm hdm}<0.25$ for $m_{\rm hdm}\leq80$ eV. Scenarios with masses above $m_{\rm hdm}\sim200$ eV remain unconstrained by the data. Next to providing limits, we investigate the potential of mixed DM to address the clustering (or $S_8$) tension between lensing and the CMB. We find a reduction of the 2D ($\Omega_m - S_8$) tension from 2.9$\sigma$ to 1.6$\sigma$ when going from a pure cold DM to a mixed DM scenario. When computing the 1D gaussian tension on $S_8$ the improvement is milder, from 2.4$\sigma$ to 2.0$\sigma$., Comment: 8 pages, 4 figures

Decaying dark matter (DDM) scenarios have recently regained attention due to their potential ability to resolve the well-known clustering (or $S_8$) tension between weak lensing (WL) and cosmic microwave background (CMB) measurements. In this paper, we investigate a well-established model where the original dark matter particle decays into a massless particle and a massive daughter particle. The latter obtains a velocity kick during the decay process that results in the suppression of the matter power spectrum at scales that are observable with WL shear observations. We perform the first fully non-linear WL analysis of this two-body decaying dark matter ($\Lambda$DDM) scenario, including intrinsic alignment and baryonic feedback processes. We used the cosmic shear band power spectra from \textit{KiDS-1000} data and combined it with temperature and polarisation data from \texttt{Planck} in order to constrain the $\Lambda$DDM model. We report new limits on the decay rate and mass splitting parameters that are significantly stronger than previous results, especially in the case of low-mass splittings. Regarding the $S_8$ tension, we found a reduction from about 3 to 2 $\sigma$, depending on which statistical measure is applied. We therefore conclude that the two-body $\Lambda$DDM model is able to reduce the $S_8$ tension without convincingly solving it., Comment: 15 pages, 13 figures

Past years have seen various publications attempting to explain the apparent clustering features of trans-Neptunian objects, the most popular explanation being an unconfirmed "Planet 9". The recently proposed Uranus Orbiter and Probe mission by NASA's Planetary Science and Astrobiology Decadal Survey could offer the opportunity to precisely determine Planet 9's sky location and mass by carefully monitoring ranging data during the interplanetary cruise. We use Monte Carlo-Markov Chain methods to reconstruct simulated spacecraft trajectories in a simplified solar system model containing Planet 9, providing an estimate of the mission's localisation capacity depending on sky location, Earth-spacecraft Doppler link noise level and data collection rate. We characterise the noise via the Allan deviation $\sigma_{\rm A}$, scaled to the Cassini-era value $\sigma_{\rm A}^{\rm \scriptscriptstyle Cass} = 3 \times 10^{-15}$, finding that daily measurements of the spacecraft position can lead to $\sim$0.2 deg$^2$ localisation of Planet 9 (assuming $M_9 = 6.3 M_{\oplus}$, $d_9 = 460$AU). As little as a 3-fold improvement in $\sigma_{\rm A}$ drastically decreases the sky localisation area size to $\sim$0.01 deg$^2$. Thus, we showcase that a future Uranus mission carries a significant potential also for non-Uranian science., Comment: Accepted for publication in MNRAS: Letters, 5 pages, 4 figures

From observations at low and high redshifts, it is well known that the bulk of dark matter (DM) has to be stable or at least very long-lived. However, the possibility that a small fraction of DM is unstable or that all DM decays with a half-life time ($\tau$) significantly longer than the age of the Universe is not ruled out. One-body decaying dark matter (DDM) consists of a minimal extension to the $\Lambda$CDM model. It causes a modification of the cosmic growth history as well as a suppression of the small-scale clustering signal, providing interesting consequences regarding the $S_8$ tension, which is the observed difference in the clustering amplitude between weak-lensing (WL) and cosmic microwave background (CMB) observations. In this paper, we investigate models in which a fraction or all DM decays into radiation, focusing on the long-lived regime, that is, $\tau \gtrsim H_0^{-1}$ ( $H_0^{-1}$ being the Hubble time). We used WL data from the Kilo-Degree Survey (KiDS) and CMB data from Planck. First, we confirm that this DDM model cannot alleviate the $S_8$ difference. We then show that the most constraining power for DM decay does not come from the nonlinear WL data, but from CMB via the integrated Sachs-Wolfe effect. From the CMB data alone, we obtain constraints of $\tau \geq 288$~Gyr if all DM is assumed to be unstable, and we show that a maximum fraction of $f=0.07$ is allowed to decay assuming the half-life time to be comparable to (or shorter than) one Hubble time. The constraints from the KiDS-1000 WL data are significantly weaker, $\tau \geq 60$~Gyr and $f<0.34$. Combining the CMB and WL data does not yield tighter constraints than the CMB alone, except for short half-life times, for which the maximum allowed fraction becomes $f=0.03$. All limits are provided at the 95% confidence level.

We investigate the possibility of detecting the gravitational influence of dark matter (DM) on the trajectory of prospective Doppler ranging missions to Uranus and Neptune. In addition, we estimate the constraints such a mission can provide on modified and massive gravity theories via extra-precession measurements using orbiters around the ice giants. We employ Monte Carlo-Markov Chain methods to reconstruct fictitious spacecraft trajectories in a simplified solar system model with varying amounts of DM. We characterise the noise on the Doppler link by the Allan deviation $\sigma_{\rm A}$, scaled on the Cassini-era value of $\sigma^{\rm{Cass}}_{\rm A}= 3 \times 10^{-15}$. Additionally, we compare the precision of prospective extra-precession measurements of Uranus and Neptune with the expected rates from simulations, in the context of modifications to the inverse square law. We estimate that the prospective mission will be sensitive to DM densities of the order of $\rho_{\rm{DM}} \sim 9 \times 10^{-20} \, (\sigma_{\rm A}/\sigma_{\rm A}^{\rm{Cass}}) $ kg/m$^3$, while the $1\sigma$ bound on the expected galactic density of $\rho_{\rm{DM}} \sim 5 \times 10^{-22}$ kg/m$^3$ decreases as $1.0 \times 10^{-20} \, (\sigma_{\rm A}/\sigma^{\rm{Cass}}_{\rm A})^{0.8}$ kg/m$^3$. An improvement of two to three orders of magnitude from the baseline Allan deviation would guarantee a local detection of DM. Only a moderate reduction in ranging noise is required to rule out Milgrom's interpolating function with solar system based observations, and improve constraints the graviton mass beyond current local- or gravitational wave-based measurements. Our analysis also highlights the potential of future ranging missions to improve measurements of the standard gravitational parameters in the solar system., Comment: Published by A&A

Bilayer graphene is a nanomaterial that allows for well-defined, separated quantum states to be defined by electrostatic gating and, therefore, provides an attractive platform to construct tunable quantum dots. When a magnetic field perpendicular to the graphene layers is applied, the graphene valley degeneracy is lifted, and splitting of the energy levels of the dot is observed. Given the experimental ability to engineer this energy valley splitting, bilayer graphene quantum dots have a great potential for hosting robust qubits. Although bilayer graphene quantum dots have been recently realized in experiments, it is critically important to devise robust methods that can identify the observed quantum states from accessible measurement data. Here, we develop an efficient algorithm for extracting the model parameters needed to characterize the states of a bilayer graphene quantum dot completely. We introduce a Hamiltonian-guided random search method and demonstrate robust identification of quantum states on both simulated and experimental data., Comment: 18 pages, 17 figures, code: https://gitlab.com/QMAI/papers/bilayergrapheneqds

Recent exploration of the commensurate structure in the turbostratic double layer graphene shows that the large angle twisting can be treated by the decrease of the effective velocity within the energy spectra of the single layer graphene. Within our work, we use this result as a starting point, aiming towards understanding the physics of by a large angle twisted double layer graphene (i.e. Moire) quantum dot systems. We show that within this simple approach using the language of the first quantization, yet another so far unrealized (not up to our knowledge), illustrative property of the commutation relation appears in the graphene physics. Intriguingly, large twisting angles show to be a suitable tunning knob of the position symmetry in the graphene systems. Complete overview of the large angle twisting on the considered dot systems is provided., Comment: 10 pages, 7 figures

Analytical approach to SLAM problem was introduced in the recent years. In our work we investigate the method numerically with the motivation of using the algorithm in a real hardware experiments. We perform a robustness test of the algorithm and apply it to the robotic hardware in two different setups. In one we try to recover a map of the environment using bearing angle measurements and radial distance measurements. The another setup utilizes only bearing angle information., Comment: Due to the misunderstanding paper had been submitted before all authors agreed on the final version