arXiv subjects

B. Abel

Publications and source records attributed to B. Abel.

4 recordsLinked to original sources

arXiv2025

photoD with Rubin's Data Preview 1: first stellar photometric distances and deficit of faint blue stars. Stellar distances with Rubin's DP1

Aims: We investigate the utility of Rubin's Data Preview 1 for estimating stellar number density profile in the Milky Way halo. Methods: Stellar broad-band near-UV to near-IR $ugrizy$ photometry released in Rubin's Data Preview 1 is used to estimate distance and metallicity for blue main sequence stars brighter than $r=24$ in three $\sim$1.1. sq.~deg. fields at southern Galactic latitudes. Results: Compared to TRILEGAL simulations of the Galaxy's stellar content by (Dal Tio, 2022), we find a significant deficit of blue main sequence turn-off stars with $22 < r < 24$. We interpret this discrepancy as a signature of a much steeper halo number density profile at galactocentric distances $10-50$ kpc than the cannonical $\sim1/r^3$ profile assumed in TRILEGAL simulations. Conclusions: This interpretation is consistent with earlier suggestions based on observations of more luminous, but much less numerous, evolved stellar populations, and a few pencil beam surveys of blue main sequence stars in the northern sky. These results bode well for the future Galactic halo exploration with Rubin's Legacy Survey of Space and Time.

astro-ph.GA↗

arXiv2025

Towards High-Resolution Orbitrap Mass Spectrometry for Next- Generation In-Situ Space Dust Analysis

Cosmic and planetary dust hold vital clues to the chemical evolution of the solar system, yet in situ analysis of their molecular and elemental composition remains technically challenging. Here we present laboratory results from HANKA (High-resolution mass Analyzer for Nano-scale Kinetic Astro materials), a compact Orbitrap-based mass spectrometer developed towards the goal of a universal dust detector for space applications. Using infrared laser ablation and plasma formation under vacuum, we analyzed solid-state samples representative of Lunar, Martian, and Meteoritic material. The resulting mass spectra - recorded at resolving powers of R=60000 - reveal complex, but characteristic element mixtures. These results demonstrate the single event sensitivity of HANKA, and its mass resolution with the ability to resolve complex mass spectra and possibly differentiate geochemical signatures across planetary bodies. The dynamic range of 3-4 orders of magnitude enables even the detection of trace compounds. The minimalistic impact sampling approach enables fast, high-precision compositional mass analysis without complex sample preparation, making the instrument well-suited for orbital, surface, or flyby missions with expected dust impacts. Our system consists of an IR-laser system that simulates impacts of nano to micron sized solid-state dust and ice particles from space. It therefore allows to perform so called analogue experiments in the laboratory. We conclude that IR- laser pulses on a solid-state material are not only well suited for ice particle impact analogues but also a good analogue experiment for solid state particle impacts on a dust detector electrode in space. Moreover, the IR laser is employed only for an optimal analogue experiment simulating the impact event - it is not necessary in space on a spacecraft detecting space dust.

astro-ph.EP↗

arXiv2014

Temperature dependent creation of nitrogen-vacancy centers in CVD diamond layers

In this work, we explore the ability of plasma assisted chemical vapor deposition (PACVD) operating under high power densities to produce thin high-quality diamond layers with a controlled doping with negatively-charged nitrogen-vacancy (NV-) centers. This luminescent defect possesses specific physical characteristics that make it suitable as an addressable solid-state electron spin for measuring magnetic fields with unprecedented sensitivity. To this aim, a relatively large number of NV- centers (> 10^12 cm^-3) should ideally be located in a thin diamond layer (a few tens of nm) close to the surface which is particularly challenging to achieve with the PACVD technique. Here we show that intentional temperature variations can be exploited to tune NV- creation efficiency during growth, allowing engineering complex stacking structures with a variable doping. Because such a temperature variation can be performed quickly and without any change of the gas phase composition, thin layers can be grown. Measurements show that despite the temperature variations, the luminescent centers incorporated using this technique exhibit spin coherence properties similar to those reached in ultra-pure bulk crystals, which suggests that they could be successfully employed in magnetometry applications.

cond-mat.mtrl-sci↗

arXiv2008

Recent progress in open quantum systems: Non-Gaussian noise and decoherence in fermionic systems

We review our recent contributions to two topics that have become of interest in the field of open, dissipative quantum systems: non-Gaussian noise and decoherence in fermionic systems. Decoherence by non-Gaussian noise, i.e. by an environment that cannot be approximated as a bath of harmonic oscillators, is important in nanostructures (e.g. qubits) where there might be strong coupling to a small number of fluctuators. We first revisit the pedagogical example of dephasing by classical telegraph noise. Then we address two models where the quantum nature of the noise becomes essential: "quantum telegraph noise" and dephasing by electronic shot noise. In fermionic systems, many-body aspects and the Pauli principle have to be taken care of when describing the loss of phase coherence. This is relevant in electronic quantum transport through metallic and semiconducting structures. Specifically, we recount our recent results regarding dephasing in a chiral interacting electron liquid, as it is realized in the electronic Mach-Zehnder interferometer. This model can be solved employing the technique of bosonization as well as a physically transparent semiclassical method.

cond-mat.mes-hall↗