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Exploring the nature of phonon-qubit-photon coupling in a hybrid circuit
No full textThe interaction between photons and phonons mediated by a third medium has significant potential for various applications in quantum information technology. Inspired by experimental investigations obtained on hybrid circuits, we aimed to develop a comprehensive theory for analytically calculating the transmission and reflection spectra, as well as obtaining eigenenergies of the circuits associated with this interaction. When analyzing the transmission spectra, we observed an intriguing correlation between the eigenenergies and the spectral peaks. This observation suggests the possibility of a deeper understanding of the stationary states involved in this unique hybrid circuit. Through this analysis, we aim not only to describe the observed phenomena but also to provide valuable insights for quantum technology
Multi-strange and charmed hadrons: a novel probe for the QCD equation of state at high baryon densities
No full textNuclear experiments near and below the threshold of hyperon production have shown that the production of Kaons is a sensitive probe for the dense QCD equation of state. At beam energies up to 1.5 AGeV, strangeness production can probe the equation of state for densities up to approximately twice nuclear saturation. In this paper, we will discuss the possibilities of extending this range in density by the study of multi-strange baryons as well as charmed hadrons in the SIS100 beam energy range up to 10 AGeV. Here, densities up to five times nuclear saturation can be reached and the production of multi-strange and charmed hadrons shows a strong sensitivity to the equation of state. On the other hand, a precise prediction of the effect of the equation of state will require knowledge of the fundamental production cross-section near the elementary production threshold in p + p collisions which is yet not measured for the hadrons discussed
Recycling Library as Fulfillment of the Right to Education and a Healthy Sustainable Environment
No full textThe fulfillment of the right to education and a sustainable healthy environment still faces serious obstacles in rural areas of Indonesia, one of which is due to limited literacy facilities and waste management, Wonorejo Public Elementary School No. 04 is a concrete example of an elementary school that does not have a library, while the level of household waste production is quite high and has the potential to cause environmental pollution. This study aims to examine the implementation of the Recycling Library as an innovative model to fulfill the right to education while strengthening ecological awareness based on school empowerment. The method used is community-based participatory research (CBPR) with a socialization-monitoring system approach through socialization, assistance, and hybrid monitoring. The results of the study show the formation of a functional library with a collection of 491 donated books, supporting tools from recycled waste, and the revitalization of previously unused school space. This program improves student literacy, fosters a culture of self-help, and reduces the potential for environmental pollution through school-based waste management. The conclusion of this study confirms that the Recycling Library is an instrument for simultaneously fulfilling the right to education and the right to a healthy environment
A long postglacial rhyolitic activity of the Icelandic Krafla volcano during the Eemian: limited impact of glacio-isostasy
No full textTephrostratigraphy in marine cores is an important tool for dating sedimentary sequences along the North Atlantic and in Western Europe. Most previously analyzed marine tephra were produced by Icelandic volcanoes, albeit rarely from the Krafla volcano, and require land-based records for validation. Two series of rhyolitic tephra emitted to the east of the Krafla volcano were recorded in the Eemian Rangá Formation in Northern Iceland, the two series being separated by the Grímsvötn 1 tephra known as “5e low bas IV” in marine core (∼127 ka). These rhyolitic deposits were seemingly ejected from the Hágangnahali paleocrater row (North of the Hágöng) and overlay the older Halarauður Ignimbrite. This rhyolitic activity persisted for ∼20 ka to the end of the Eemian last thermal optimum. probably initiated by deglaciation (MIS 6a/5e). It postdated the Halarauður ignimbrite. The ignimbrite and caldera formation were correlated with an ODP907 tephra, yielding a possible 207 ka age, but possibly older. These results constrain the main rhyolitic activity of Krafla to after the mid-Pleistocene transition, as observed for other “two-magma” volcanoes. Rhyolitic activity is non-systematically triggered by deglaciation, at least as analysed during the period 80–400 ka, but this genetic link is possibly valid for the late Pliocene of Iceland
Comparison of the modelled geoelectric fields of the Carrington and Halloween storms
No full textAn extreme geomagnetic storm comparable to the Carrington event in 1859 could have a significant impact on modern infrastructure, such as power grids. A previously published simulation by Blake et al. (2021, Space Weather, https://doi.org/10.1029/2020SW00258
Curved space-time corrections to Faraday rotation in magnetized plasmas far from Schwarzschild black holes
No full textContext. In this manuscript, we analyze the effect of Schwarzschild space-time curvature on the Faraday rotation of quasi-monochromatic circularly polarized electromagnetic waves.
Aims. We show how the plane of polarization of the electromagnetic waves is rotated, retaining information about the source of space-time curvature and the plasma properties around it.
Methods. We investigate right-handed and left-handed circularly polarized electromagnetic waves propagating in this space-time along a radial magnetic field in a multicomponent plasma. The coupling between the plasma and the gravitational field produces corrections to the Faraday rotation proportional to the ratio of the black hole’s Schwarzschild radius to the (far) distance to it, the plasma frequency, and the inverse of the wave’s frequency.
Results. In general, the rotation angle provides information about the plasma properties, the external magnetic field, and the Schwarzschild black hole mass. Hence, we propose that Faraday rotation can be used to obtain information not only about magnetized plasma but also about static astrophysical compact objects that curve space-time
The core-shift of Sagittarius A* as a discriminant between disk and jet emission models with millimeter very long baseline interferometry
No full textContext. The nature of the emission region around Sagittarius A* (Sgr A*), the supermassive black hole at the Galactic center, remains under debate. A prediction of jet models is that a frequency-dependent shift in the position of the radio core (i.e., core-shift) of an active galactic nucleus (AGN) occurs when observing emission dominated by a highly collimated relativistic outflow.
Aims. We use millimeter very long baseline interferometry to study the frequency-dependent position of Sgr A*’s radio core, estimate the core-shift for different emission models, investigate the core-shift evolution as a function of viewing angle and orientation, and study its behavior in the presence of interstellar scattering.
Methods. We simulated images of the emission around Sgr A* for accretion inflow models (disks) and relativistic outflow models (jets). They were based on three-dimensional general relativistic magnetohydrodynamic simulations. We created flux density maps at 22, 43, and 86 GHz sampling different viewing angles and orientations of Sgr A*, examined the effects of scattering, and simulated observations with the Very Long Baseline Array (VLBA).
Results. Jet-dominated models show significantly larger core-shifts than disk-dominated models – in some cases by a factor of 16 – with intermediate viewing angles (i = 30° ,45°) showing the largest core-shifts. Our jet models follow a power-law relation for the frequency-dependent position of Sgr A*’s core. Their core-shifts decrease as the position angle increases from 0° to 90°. Disk models do not fit a power-law relation well and their core-shifts are insensitive to changes in the viewing angle. We obtain a maximum value of 241.65 ± 1.93 μas cm−1 for the core-shift of jet models including refractive scattering in an ideal case. In addition, the same models observed by the VLBA yield a value of 215.57 ± 1.95 μas cm−1.
Conclusions. The core-shift can serve as a tool to discriminate between jet- and disk-dominated models and to constrain the geometry of Sgr A*. Our jet models agree with earlier predictions of AGNs with collimated jets, and the core-shift is retrievable even in the presence of interstellar scattering and when simulating observations
Physical interpretation of the oscillation spectrum on the red giant branch and the asymptotic giant branch
No full textContext. The high frequency resolution of the four-year time series collected by the space-borne telescope Kepler provides us the opportunity to study the seismic mode structure of highly luminous giants in great detail. Seismic observables can be used to infer the interior structure through comparisons with stellar models. However, we still need to extend the physical interpretation of previously observed seismic differences between hydrogen-shell burning (red giant branch; RGB) and helium-burning (red clump and asymptotic giant branch; AGB) stars towards high luminosity stages.
Aims. Here we aim to investigate which physical conditions differ between H-shell and He-burning stars in the helium-second ionisation zone, based on the signature this zone imprints on mode frequencies. In addition, we explore the sensitivity of seismic parameters to the physics implemented in the models.
Methods. We used a grid of stellar models with masses between 0.8 M⊙ and 2.5 M⊙ and metallicities between −1.0 dex and 0.25 dex. Transfer mechanisms such as mass loss, core, envelope overshooting, and thermohaline mixing were implemented. We inferred the p-mode frequencies of the models by artificially suppressing the gravity modes in the core.
Results. In accordance with observations, we find that the main stellar properties affecting the seismic observables in the models are the stellar mass and metallicity. Mass loss on the RGB and rotation-induced mixing from the main sequence to the early-AGB cause a phase difference in the helium ionisation zone glitch signature between H-shell and He-burning stars. The amplitude of the glitch signature in the local large separation, Δν, correlates with the density in the helium ionisation zone, which explains the different glitch amplitudes observed between the H-shell and He-burning stars. The amplitude exceeds 10% of the observed value of Δν in high-luminosity red giants, which makes the asymptotic expansion less accurate when Δν ≤ 0.5 μHz.
Conclusions. An efficient mass loss on the RGB, typically encountered when M ≤ 1.5 M⊙, can explain the classification of H-shell and He-burning stars based on the p-mode pattern. When M ≥ 1.5 M⊙, efficient mixing mechanisms might leave an important detectable signature in the p-mode frequencies, permitting a potential classification of these stars
Observational probes of the neutron star equation of state with hyperons, bosonic dark matter, and quark matter
No full textContext. The presence of dark matter in neutron stars is of growing interest due to its potential impact on the structure and observable properties of these objects. Among the various candidates, the hypothetical sexaquark has emerged as a promising bosonic dark matter particle, potentially forming under extreme conditions in neutron star cores.
Aims. We investigate whether a hybrid neutron star model that includes hyperons, bosonic dark matter (in the form of sexaquarks), and deconfined quark matter can satisfy all current observational constraints. We particularly focus on identifying the range of sexaquark masses consistent with mass-radius measurements and the tidal deformability limit.
Methods. We used the DD2Y-T model for the hadronic phase, which includes hyperons, and a nonlocal Nambu–Jona-Lasinio model for the deconfined quark phase. The phase transition was modeled as a smooth crossover using the replacement interpolation construction method. Sexaquark-baryon interactions were introduced via an effective mass shift representing repulsion. We incorporated the full set of current observational data, including NICER measurements of PSRs J0437–4715 and newly published J0614–3329 data, and performed a Bayesian analysis to constrain the sexaquark mass.
Results. Our results show that the presence of the sexaquark softens the equation of state, enabling the hybrid model to satisfy both the radius and tidal deformability constraints around the canonical 1.4 M⊙ neutron stars. We find that hybrid EOSs with a sexaquark mass around 1900 MeV are in agreement with all available constraints, including those from HESS J1731–347 and PSR J0952–0607, which represent the lowest and highest mass neutron stars observed to date. The Bayesian analysis favors a sexaquark mass range of 1885–1935 MeV, supporting the potential relevance of this exotic particle in neutron star interiors
A new sample of massive B-type contact binary candidates from the OGLE survey of the Magellanic Clouds
No full textContext. Massive contact binaries (CBs) are crucial objects for understanding close binary evolution and stellar mergers. Study of these objects has been hampered by a scarcity of observed systems, particularly of B-type systems which are expected to dominate this class.
Aims. We bridge this observational gap by mining a large sample of massive CB candidates from the OGLE-IV database, potentially increasing their current numbers in the Magellanic Clouds by an order of magnitude.
Methods. Using main-sequence color-magnitude limits, an observationally informed period-luminosity-color relation for CBs, and a high morph parameter cut (c ≥ 0.7), we empirically identified a subsample of 68 O and B-type binaries with periods P < 3 days, that exhibit smooth, sinusoidal light curves with nearly equal eclipse depths. To mine our bona fide sample of CB candidates among these, we used theoretical color-magnitude and orbital period distributions based on a vast grid of MES