Using the Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY) we performed an untargeted search for H I-bearing ultra-diffuse galaxies (UDGs). We identified a core sample of 10 UDGs defined by $\mu_{g,0}\ge24$ mag arcsec$^{-2}$ and $R_{e}\ge1.5$ kpc, and a broader sample including 12 additional faint diffuse galaxies ($\mu_{g,0}\ge23.7$ mag arcsec$^{-2}$ and $R_{e}\ge1.3$ kpc). Within the core sample, we highlight the first discovery of a UDG pair. Their projected separation is just 75 arcsec (22 kpc at 61.9 Mpc), with a central H I velocity difference of 34 km s$^{-1}$. The North-Western UDG (WALLABY J104513-262755-UDG-1) has a larger H I reservoir, $\log_{10}(M_{HI}/\rm M_{\odot}) = 8.95\pm0.03$, compared to the South-Eastern UDG (WALLABY J104513-262755-UDG-2), $\log_{10}(M_{HI}/\rm M_{\odot}) = 8.60\pm0.04$. UDG-1's stellar mass and star formation rate are also approximately an order of magnitude larger at $\log_{10}(M_*/\rm M_{\odot}) = 8.07\pm0.12$ and $\log_{10}(SFR/\rm M_{\odot}~yr^{-1}) = -1.26\pm0.12$ respectively. The pair has an isolated local environment, with no other galaxies or H I sources within 30 arcmin (525 kpc) and $\pm1000$ km s$^{-1}$. However, in the context of the larger-scale structure, the pair is located outside the virial radius of the Hydra cluster, with its position on the phase-space diagram indicating that it is infalling into the cluster. The identification of this H I-bearing UDG pair raises important questions around the formation of such a unique system and the evolution of UDGs in a transitional phase before ram pressure stripping and cluster infall.

The proliferation of cell-free Massive MIMO represents a transformative shift in wireless network architecture, addressing critical limitations of conventional distributed Massive MIMO systems. This paper presents an intelligent radio network planning framework that bridges legacy 5G infrastructures with future B5G/6G networks through cell-free architectures. By leveraging operational insights from existing 5G deployments, we systematically address coverage optimization, and capacity enhancement. Our scalable framework enables seamless evolution from legacy designs to next-generation cell-free systems. Through extensive simulations in dense urban environments, we demonstrate substantial improvements: 45% spectral efficiency gains, 30% interference reduction, and significantly enhanced uniform coverage. The proposed framework provides network operators with a practical roadmap for transitioning from traditional cellular architectures to demanding B5G/6G requirements while maximizing existing infrastructure investments.

With the aim of evaluating the roles of the cold neutral medium (CNM) in the cloud-scale baryon cycle, we perform a high-resolution study of the CNM in and around the extreme star-forming region 30 Doradus (30 Dor). For our study, we use Galactic Australian Square Kilometre Array Pathfinder H I Survey data and produce H I emission and absorption cubes on 7 pc scales. To examine the CNM structures toward 30 Dor, we decompose the H I absorption cube into 862 Gaussian components and find that these components are distributed at four velocity ranges (B1, B2, B3, and B4, respectively): 200$-$230 km s$^{-1}$, 230$-$260 km s$^{-1}$, 260$-$277 km s$^{-1}$, and 277$-$300 km s$^{-1}$. We derive line-of-sight average spin temperatures and opacity-corrected total H I column densities and show that the B1$-$B4 structures have systematically different properties, indicating that they are physically distinct. As for the nature of the observed CNM structures, we find that B2 is associated with the main dense structure where ionized, atomic, and molecular gases are concentrated. B3 and B4 trace inflows whose combined mass flux rate of 0.14 $M_{\odot}$ yr$^{-1}$ is comparable to the current star formation rate, while B1 probes outflows with a much lower mass flux rate of 0.007 $M_{\odot}$ yr$^{-1}$. Interestingly, the H I column densities in B1$-$B4 are nearly uniform with a factor of two spatial variations, implying the presence of H I shielding layers for H$_{2}$ formation.

The spin activity in macromolecules such as DNA and oligopeptides, in the context of the Chiral Induced Spin Selectivity (CISS) has been proposed to be due to the atomic Spin-Orbit Coupling (SOC) and the associated chiral symmetry of the structures. This coupling, associated with carbon, nitrogen and oxygen atoms in biological molecules, albeit small (meV), can be enhanced by the geometry, and strong local polarization effects such as hydrogen bonding (HB). A novel way to manipulate the spin degree of freedom is by modifying the spectrum using a coupling to the appropriate electromagnetic radiation field. Here we use the Floquet formalism in order to show how the half filled band Hamiltonian for DNA, can be modulated by the radiation to produce a up to a tenfold increase of the effective SOC once the intrinsic coupling is present. On the other hand, the chiral model, once incorporating the orbital angular momentum of electron motion on the helix, opens a gap for different helicity states (helicity splitting) that chooses spin polarization according to transport direction and chirality, without breaking time reversal symmetry. The observed effects are feasible in physically reasonable parameter ranges for the radiation field amplitude and frequency.

In this work we construct a static and spherically symmetric black hole geometry supported by a family of generic mono-parametric sources thorough the Gravitational Decoupling. The parameter characterizing the matter sector can be interpreted as hair which cannot be associated to any global charge. Although the solution is constructed by demanding the weak energy condition, we find that the resulting matter sector satisfies all the energy conditions at and outside the horizon. We study the effect of the hair on the periastron advance and the gravitational lensing of the black hole. We estimate the best WKB order to compute the quasinormal frequencies for scalar, vector and tensor perturbation fields.

Black holes with hair represented by generic fields surrounding the central source of the vacuum Schwarzschild metric are examined under the minimal set of requirements consisting of i) the existence of a well defined event horizon and ii) the strong or dominant energy condition for the hair outside the horizon. We develop our analysis by means of the gravitational decoupling approach. We find that trivial deformations of the seed Schwarzschild vacuum preserve the energy conditions and provide a new mechanism to evade the no-hair theorem based on a primary hair associated with the charge generating these transformations. Under the above conditions i) and ii), this charge consistently increases the entropy from the minimum value given by the Schwarzschild geometry. As a direct application, we find a non-trivial extension of the Reissner-Nordstrom black hole showing a surprisingly simple horizon. Finally, the non-linear electrodynamics generating this new solution is fully specified.

Context. Teegarden's Star is the brightest and one of the nearest ultra-cool dwarfs in the solar neighbourhood. For its late spectral type (M7.0V), the star shows relatively little activity and is a prime target for near-infrared radial velocity surveys such as CARMENES. Aims. As part of the CARMENES search for exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements of Teegarden's Star and analysed them for planetary signals. Methods. We find periodic variability in the radial velocities of Teegarden's Star. We also studied photometric measurements to rule out stellar brightness variations mimicking planetary signals. Results. We find evidence for two planet candidates, each with $1.1M_\oplus$ minimum mass, orbiting at periods of 4.91 and 11.4 d, respectively. No evidence for planetary transits could be found in archival and follow-up photometry. Small photometric variability is suggestive of slow rotation and old age. Conclusions. The two planets are among the lowest-mass planets discovered so far, and they are the first Earth-mass planets around an ultra-cool dwarf for which the masses have been determined using radial velocities.

Securing information in future mobile networks is challenging, especially for devices with limited computational resources. Physical layer security (PLS) offers a viable solution by leveraging wireless channel randomness. When full secrecy is unattainable, the partial secrecy regime provides a realistic alternative. This work analyzes partial secrecy performance under the generalized multicluster fluctuating two-ray (MFTR) fading model, which subsumes many classical fading cases. We study a system with a transmitter (A), legitimate receiver (B), and eavesdropper (E), both B and E using antenna arrays with maximal ratio combining (MRC), under i.n.i.d. fading. Exact and closed-form approximations are derived for key secrecy metrics: generalized secrecy outage probability (GSOP), average fractional equivocation (AFE), and average information leakage rate (AILR). The results, validated by Monte Carlo simulations, retain constant complexity regardless of diversity order. The MFTR model's flexibility enables comprehensive assessment across fading conditions, showing that more MRC branches at B enhance secrecy performance depending on the A-E link characteristics.

Chiral structures, breaking spatial inversion symmetry, exhibit non-zero chiroptical activity (COA) due to the interaction between their electric and magnetic responses under external electromagnetic fields, an effect that is otherwise absent in achiral systems. Non-magnetic chiral structures also exhibit Chiral Induced Spin Selectivity (CISS), where spin-polarization (SP) emerges without external magnetic influence. We have obtained a COA-SP connection for a model system of an electron constrained to a helix including spin-orbit coupling (SOC), and in the presence of an external electromagnetic field. Despite its simplicity, this model captures the relevant physics required to address the problem. In particular, our results reveal that the norm of the SP vector can be used as a predictor of COA. In addition to SOC and the breaking of space inversion, a non-vanishing SP requires the breaking of time-reversal symmetry (TRS), as demanded by Onsager's reciprocity. Beyond the relationship between SP and COA, we obtain the novel result that TRS breaking is also necessary to yield a non-vanishing contribution of the SOC to the COA.

We study the spontaneous scalarization of charged black holes in Einstein's gravity minimally coupled to power--Maxwell electrodynamics which, in turn, is non--minimally coupled to a real scalar field. We point out the existence of a specific power for which the scalarized solution is well-behaved, and entropically preferred in comparison to the scalar-free charged black hole solution.

In this work, we introduce a new fractional derivative that modifies the conventional Riemann-Liouville operator to obtain a set of fractional Einstein field equations within a 2+1 dimensional spacetime by assuming a static and circularly symmetric metric. The main reason for introducing this new derivative stems from addressing the divergence encountered during the construction of Christoffel symbols when using the Caputo operator and the appearance of unwanted terms when using the Riemann-Liouville derivative because of the well-known fact that its action on constants does not vanish, as expected. The key innovation of the new operator ensures that the derivative of a constant is zero. As a particular application, we explore whether the Bañados-Teitelboim-Zanelli black hole metric is a solution to fractional Einstein equations. Our results reveal that for values of the fractional parameter close to one, the effective matter sector corresponds to a charged BTZ solution with an anisotropic cosmological constant.

In a recent paper (Phys. Dark Univ. {\bf 31}, 100744 (2021)) it has been obtained new static black hole solutions with primary hairs by the Gravitational Decoupling. In this work we either study the geodesic motion of massive and massless particles around those solutions and restrict the values of the primary hairs by observational data. In particular, we obtain the effective potential, the innermost stable circular orbits, the marginally bounded orbit, and the periastron advance for time--like geodesics. In order to restrict the values taken by the primary hairs we explore their relationship with the rotation parameter of the Kerr black hole giving the same innermost stable circular orbit radius and give the numerical values for the supermassive black holes at Ark 564 and NGC 1365. The photon sphere and the impact parameter associated to null geodesics are also discussed.

We report on recent progress in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC, updating the information in the original Letter of Intent (LoI), see CDS:LHCC-I-031, arXiv:1811.00927. A suitable site has been identified at LHC Point 5 that is closer to the CMS Interaction Point (IP) than assumed in the LoI. The decay volume has been increased from 20 m to 25 m in height. Engineering studies have been made in order to locate much of the decay volume below ground, bringing the detector even closer to the IP. With these changes, a 100 m x 100 m detector has the same physics reach for large c$\tau$ as the 200 m x 200 m detector described in the LoI and other studies. The performance for small c$\tau$ is improved because of the proximity to the IP. Detector technology has also evolved while retaining the strip-like sensor geometry in Resistive Plate Chambers (RPC) described in the LoI. The present design uses extruded scintillator bars read out using wavelength shifting fibers and silicon photomultipliers (SiPM). Operations will be simpler and more robust with much lower operating voltages and without the use of greenhouse gases. Manufacturing is straightforward and should result in cost savings. Understanding of backgrounds has also significantly advanced, thanks to new simulation studies and measurements taken at the MATHUSLA test stand operating above ATLAS in 2018. We discuss next steps for the MATHUSLA collaboration, and identify areas where new members can make particularly important contributions.

A very famous ``test'' of the General Theory of Relativity (GTR) is the advance of Mercury's perihelion (and of other planets too). To be more precise, this is not a prediction of General Relativity, since the anomaly was known in the XIXth century, but no consistent explanation had been found yet at the time GTR was elaborated. Einstein came up with a solution to the problem in 1914. In the case of Mercury, the closest planet to the Sun, the effect is more pronounced than for other planets, and observed from Earth; there is an advance of the perihelion of Mercury of about 5550~arc seconds per century (as/cy). Among these, about $5000$ are due to the equinox precession (the precise value is {$5025.645$}~as/cy) and about $500$ ({$531.54$}) to the influence of the external planets. The remaining, about $50$~as/cy ({$42.56$}), are not understood within Newtonian mechanics. Here, we revisit the problem in some detail for a presentation at the undergraduate level.

We study theoretically the emission and lasing properties of a single nanoshell spaser nanoparticle, or plasmonic nanolaser, made of an active core (gain material) and a plasmonic metal shell. Based on an analytical framework coupling together time-dependent equations for the gain and the metal, we calculate the lasing threshold with the help of an instability analysis. We characterize the regime under the threshold, where the nanoshell behaves as an optical amplifier when excited by an incident probe field. We then investigate in depth the non-linear lasing regime above the threshold, under autonomous conditions (free lasing without external drive), by computing the system's dynamics both in the transient state and in the final steady state. We show that at threshold, the lasing starts at one frequency only, usually one of the plasmon resonances of the nanoshell; then as the gain is further raised, the emission widens to other frequencies. This differs significantly from previous findings in the literature, which found only one emission wavelength above threshold. We proceed to calculate the complete (maximal) emission spectrum of the nanolaser as well as its emission linewidth, both of which are evidenced to be affected by unusually strong frequency shifts (pull-out) effects. We find that the nanolaser emission is highly asymmetrical spectrally and only occurs on one side (high-frequency) of the plasmon resonance. Finally, we show that the spectral position of the emission line can be tuned across the whole visible range, by changing the geometrical aspect ratio of the nanoshell.

During outbreaks of emerging infectious diseases, internationally connected cities often experience large and early outbreaks, while rural regions follow after some delay. This hierarchical structure of disease spread is influenced primarily by the multiscale structure of human mobility. However, during the COVID-19 epidemic, public health responses typically did not take into consideration the explicit spatial structure of human mobility when designing non-pharmaceutical interventions (NPIs). NPIs were applied primarily at national or regional scales. Here we use weekly anonymized and aggregated human mobility data and spatially highly resolved data on COVID-19 cases, deaths and hospitalizations at the municipality level in Mexico to investigate how behavioural changes in response to the pandemic have altered the spatial scales of transmission and interventions during its first wave (March - June 2020). We find that the epidemic dynamics in Mexico were initially driven by SARS-CoV-2 exports from Mexico State and Mexico City, where early outbreaks occurred. The mobility network shifted after the implementation of interventions in late March 2020, and the mobility network communities became more disjointed while epidemics in these communities became increasingly synchronised. Our results provide actionable and dynamic insights into how to use network science and epidemiological modelling to inform the spatial scale at which interventions are most impactful in mitigating the spread of COVID-19 and infectious diseases in general.

Accurate channel modeling plays a pivotal role in optimizing communication systems, and fitting field measurements to stochastic models is crucial for capturing the key propagation features and to map these to achievable system performances. In this work, we shed light onto what's the most appropriate alternative for channel fitting, when the ultimate goal is performance analysis. Results show that likelihood-based and average-error metrics should be used with caution, since they can largely fail to predict outage probability measures. We show that supremum-error fitting metrics with tail awareness are more robust to estimate both ergodic and outage performance measures, even when they yield a larger average-error fitting.

In this work, we analyze the behavior of light and matter as they pass near and through a traversable wormhole. In particular, we study the trajectories of massive and massless particles and the dust accretion around a traversable wormhole previously reported in Eur. Phys. J. C \textbf{82} (2022) no.7, 605. For massive particles, we integrate the trajectory equation for ingoing and outgoing geodesics and classify the orbits of particles scattered by the wormhole in accordance with their asymptotic behavior far from the throat. We represent all the time--like trajectories in an embedding surface where it is shown explicitly the trajectories of i) particles that deviate from the throat and remain in the same universe, ii) particles that traverse the wormhole to another universe, and iii) particles that get trapped in the wormhole in unstable circular orbits. For the massless particles, we numerically integrate the trajectory equation to show the ray-tracing around the wormhole specifying the particles that traverse the wormhole and those that are only deviated by the throat. For the study of accretion, we consider the steady and spherically symmetric accretion of dust. Our results show that the wormhole parameters can significantly affect the behavior of light and matter near the wormhole. Some comparisons with the behavior of matter around black holes are made.

This Letter describes measurements of inclusive W (--> e nu) + n jet cross sections (n = 1-4), presented as total inclusive cross sections and differentially in the nth jet transverse momentum. The measurements are made using data corresponding to an integrated luminosity of 4.2 fb-1 collected by the D0 detector at the Fermilab Tevatron Collider, and achieve considerably smaller uncertainties on W +jets production cross sections than previous measurements. The measurements are compared to next-to-leading order perturbative QCD (pQCD) calculations in the n =1-3 jet multiplicity bins and to leading order pQCD calculations in the 4-jet bin. The measurements are generally in agreement with pQCD predictions, although certain regions of phase space are identified where the calculations could be improved.

We investigate gain-assisted optical forces on dye-enriched silver nanoshell in the quasi-static limit by means of a theoretical/numerical approach. We demonstrate the onset of nonlinear optical trapping of these resonant nanostructures in a counterpropagating Gaussian beam configuration. We study the optical forces and trapping behaviour as a function of wavelength, particle gain level, and laser power. We support the theoretical analysis with Brownian dynamics simulations that show how particle position locking is achieved at high gains in extended optical trapping potentials. Finally, for wavelengths blue-detuned with respect to the plasmon-enhanced resonance,we observe particle channeling by the standing wave antinodes due to gradient force reversal. This work opens perspectives for gain-assisted optomechanics where nonlinear optical forces are finely tuned to efficiently trap, manipulate, channel, and deliver externally controlled nanophotonic system.