Papers

We study pole-skipping for a scalar field in the JT/AdS$_2$ black-hole background. Previous work established the local mechanism: at a pole-skipping point, a near-horizon recurrence relation becomes degenerate and an additional regular expansion coefficient is left undetermined. We take this local degeneracy as the starting point and track two independent solutions normalized at the AdS boundary, denoted by $R_1$ and $R_2$ for the source and response branches, respectively. Let $\widehat A$ and $\widehat B$ denote the source and response coefficients after their common singular factor is removed, and let $\chi_\mu$ denote the universal ingoing horizon factor. We find \[ \widehat A=0 \Longleftrightarrow \frac{R_2}{\chi_\mu}\in C^\infty, \qquad \widehat B=0 \Longleftrightarrow \frac{R_1}{\chi_\mu}\in C^\infty . \] Thus the source and response zeros correspond separately to horizon smoothness of the two boundary-normalized solutions after the ingoing factor is removed. At integer resonance the local regular solution contains an additional coefficient $a_N$. In the JT/AdS$_2$ model, continuation of the nonresonant ingoing solution fixes $a_N=0$ and thereby selects a unique retarded value at resonance, although unrestricted approaches in parameter space remain path dependent. At the endpoint of the pole-skipping lattice, the response branch is a lowest-weight state of the background $SL(2,\mathbb R)$ symmetry. A static holographic-superconductor example further shows that simultaneous horizon smoothness is insufficient if the two boundary branches are linearly dependent. A two-branch pole-zero intersection therefore requires \[ W[R_1,R_2]\neq0. \] These results distinguish the known local horizon degeneracy from the global relation between boundary branches and the resonant horizon solution space.

We study continuously monitored dynamics of a quasiperiodic free-fermion chain defined on a Fibonacci lattice. We focus on fluctuations of the local particle number, which do not exhibit quasiperiodic spatial modulation in the unitary limit. Remarkably, we demonstrate that they exhibit a nonuniform spatial pattern originating from the quasiperiodic long-range order under continuous measurement. Furthermore, employing both physicaland perpendicular-space analyses, we elucidate that a measurement-induced crossover emerges in fluctuations due to the interplay between the incommensurate modulation and the continuous measurement. While weak measurement yields a distribution reflecting the long-range spatial structure of the quasiperiodic system, an increase in measurement strength alters the distribution into one dominated by the local environment of each site. A structure-factor analysis further reveals that the weak-measurement regime is characterized by two dominant Bragg peaks corresponding to the golden-mean modulation, whereas the strong-measurement regime exhibits the characteristic Bragg-peak hierarchy of the Fibonacci pattern. We also elucidate that the measurement-induced crossover emerges in other physical quantities such as connected correlation functions. These findings offer insights into nonequilibrium quasiperiodic phenomena emerging in continuously monitored dynamics.

$^{14}$N NMR is notoriously difficult to perform in liquids due to the very fast spin relaxation and the large quadrupolar couplings, which render many signals invisible. We show here how $^{14}$N nuclei of biomolecular constituents can be probed indirectly by reintroducing the scalar relaxation of the second kind contribution to the polarization lifetimes of J-coupled protons in double resonance spin-locking experiments. The enhanced $^1$H relaxation rates in the rotating-frame allow for direct evaluation of nitrogen chemical shift and polarization lifetimes, from which one- and even two-bond $^1$H-$^{14}$N scalar couplings as well as $^{14}$N quadrupolar interactions can be determined. We demonstrate the versatility of this method by characterizing $^1$H-$^{14}$N spin pairs in several molecules of biological importance, showing proton relaxation enhancements beyond one order of magnitude. We further observe a pronounced effect from intermolecular hydrogen bonding. Our approach can be readily integrated into existing biomolecular NMR methodologies, as demonstrated here for $^1$H-detected relaxation-editing experiments with water suppression. This method provides access to nitrogen's picosecond-modulated quadrupolar interaction via single-scan proton detection in systems that would otherwise yield almost no detectable direct $^{14}$N signal even after averaging over thousands of transients.

Black hole singularities still remain a central challenge in gravitational physics. In this work, we present a geometric interpretation of non singular black hole cores within teleparallel gravity based on geometric drift vectors. Gravitational effects are encoded in a comoving tetrad framework through a dynamical drift field whose gradients generate torsion rather than spacetime curvature. While the teleparallel equivalent of general relativity reproduces the Schwarzschild behavior in the weak field regime, nonlinear invariant contributions dominate in the strong field region, replacing the central singular behavior with a smooth de Sitter like core. Event horizons emerge as drift horizons associated with the limiting behavior of the geometric flow, and null and timelike trajectories admit analytic extensions across the horizon and central region.

We study the emergence of generic quantum chaos from an arithmetic billiard in the hyperbolic plane. Starting from an arithmetic triangle, we introduce small area-preserving geometric perturbations and compute long consecutive sequences of eigenvalues and eigenstates. The spectral statistics show a perturbation-dependent crossover from Poisson-like arithmetic behaviour to the Gaussian orthogonal ensemble (GOE), with the crossover scale moving to higher wavenumbers as the perturbation decreases. To characterize the nearest-neighbour spacing distribution, we compare the data with Brody and generalized-gamma fits. The generalized-gamma form is used only as a two-parameter diagnostic, allowing the small- and intermediate-spacing structure to vary independently from the large-spacing tail, rather than as a universal crossover law. For the weakest perturbation, we also compare the data with an effective block-GOE model, which diagnoses residual block-like structure deep into the computed spectral range. We complement the spectral analysis with Poincaré-Husimi representations of the eigenstates and quantify phase-space localization using an entropy-based measure. Its distribution is well described by Beta distributions whose width decays as a power law in the wavenumber. Before the spectral crossover, the localization statistics retain memory of the near-arithmetic regime. After the GOE regime is reached, the localization-fluctuation widths collapse onto a common decay law, sigma(Beta) ~ k^{-eta}, with eta approximately 0.37–0.38. These results provide a combined spectral and eigenfunction-level picture of the arithmetic-to-GOE crossover in hyperbolic quantum billiards.

An open quantum system can be described by a master equation, of which one of the most popular is the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) equation. We revisit description of driven-dissipative quantum systems focusing on the appropriate choice of the system's basis and the respective transformations. We consider the GKSL equation in different bases and calculate the dynamics for a qubit and for a qudit. An appropriate choice of the basis is a fundamental problem for theoretical consideration of open quantum systems and provides an opportunity to obtain the desired evolution in practice.

The phase-field model regularizes sharp fractures into a diffuse representation, blurring the boundary between the fracture and the intact material. This blurring makes it difficult to capture distinct domain processes in hydraulic fracturing, where Reynolds flow governs the fracture and Darcy flow describes the surrounding porous matrix. Consequently, the blurred delineation artificially smears the pressure field across the fracture–matrix interface, which is acceptable in toughness-dominated hydraulic fracturing regimes where pressure drops within the fracture are negligible. However, in viscosity-dominated regimes, typically for actual subsurface injections due to high injection rates, the fluid pressure drops more drastically, and the fluid front may even lag behind the propagating fracture tip, a phenomenon that a smeared pressure field cannot capture. Despite its relevance, the viscosity-dominated regime has not been addressed by any existing phase-field models to date, likely due to its numerical instability. In this study, we propose a dual–continuum phase-field model based on double-porosity microporomechanics that explicitly separates mesoscale crack pressure from micropore pressure. The framework provides a variationally consistent formulation alongside phase-field–dependent poroelasticity. To ensure the numerical stability of the hydromechanical coupling, a fixed-stress split scheme is modified for two independent fluid pressures, while a variational inequality constraint is applied to reproduce fluid lag. Verified against the closed-form solutions in toughness-dominated, viscosity-dominated, and early-time transitional regimes, the model accurately captures complex fluid flow behavior and transient fluid lag within the fracture, and opens a new frontier for applying phase-field models to realistic viscosity-dominated hydraulic fracturing.

We revisit a minimal fermion-portal scalar dark matter model consisting of a real singlet scalar dark matter candidate and additional vector-like singlet and doublet charged fermions stabilized by a discrete $Z_2$ symmetry. In light of the latest dark matter direct-detection constraints, the conventional Higgs-portal interaction is severely restricted, motivating a detailed investigation of fermion-mediated dark matter annihilation channels. We perform a comprehensive analysis of the model parameter space by incorporating theoretical constraints from vacuum stability and perturbative unitarity, together with experimental bounds from relic density measurements, direct-detection experiments, Higgs invisible decay searches, lepton-flavor-violating processes, and anomalous magnetic moments. We show that the observed dark matter relic abundance can be successfully reproduced over a wide mass range through Yukawa-driven $t$- and $u$-annihilation and co-annihilation processes involving the new fermions, while remaining consistent with current direct-detection limits. Motivated by the viable parameter space, we investigate the discovery prospects of the lightest charged vector-like fermion at future muon colliders operating at center-of-mass energies of 3 TeV and 10 TeV. Focusing on the process $\mu^+\mu^- \to E_1^+E_1^- \to e^+e^- + \cancel{E}_T$, we perform a detector-level analysis including realistic Standard Model backgrounds. We demonstrate that the clean experimental environment of a muon collider provides excellent sensitivity to charged fermion masses extending into the multi-TeV regime, significantly improving the exploration prospects of this class of fermion-portal dark matter scenarios.

This work presents an investigation of the interstellar extinction law toward 105 Galactic open clusters using ultraviolet-optical photometry. The photometric dataset and reddening determinations were previously introduced in Ramezani et al., (2025); hereafter Paper I, where homogeneous ultraviolet photometry and colour-colour diagrams were used to derive reddening values for the cluster sample. In the present study, we extend that analysis by determining extinction law and metallicity parameters for the same clusters. Ground-based U-band observations obtained with the 2.15-m CASLEO telescope and the 1.54-m Danish telescope are combined with Gaia Data Release 3 photometry to construct ultraviolet-optical colour indices. Using extinction-ratio combinations and the Fitzpatrick, (1999) extinction model, we derive mean total-to-selective extinction law values (RV) for all clusters. The resulting RV values span approximately 2.5-4.5, with a mean value of RV = 3.53, indicating significant spatial variations of dust properties across the Galactic disk and deviations from the canonical diffuse interstellar medium value RV = 3.1. Afterward, by fitting the isochrone to the Colour-Magnitude Diagrams, we estimated the metallicity values of 105 observed clusters. This work provides the first homogeneous catalogue of extinction law measurements based on combined ground-based ultraviolet and Gaia photometry for a large open-cluster sample, establishing an important reference for studies of Galactic dust structure and stellar parameter corrections.

Quantum entanglement is widely used as a diagnostic of topological phases of matter. Beyond entanglement, non-stabilizerness captures a distinct aspect of quantum many-body states by quantifying their distance from the manifold of stabilizer states. In this work, we study the stabilizer Rényi entropy in symmetry protected topological (SPT) phases, including both gapped SPT, non-intrinsically gapless SPT, and intrinsically gapless SPT phases. Under symmetry preserving perturbations, we find numerically that the stabilizer Rényi entropy exhibits an extremum near the phase transition. However, the stabilizer Rényi entropy alone cannot distinguish different SPT phases. In contrast, the Pauli spectrum reveals a characteristic crossing structure at the transition point. This crossing reflects the exchange of dominant Pauli-string correlations associated with the non-local string order parameters of the two topological distinct phases. For gapped SPT and non-intrinsically gapless SPT phases, the crossing structure can be understood from a local-unitary duality that maps the Pauli spectrum between the two phases. For intrinsically gapless SPT phases, such a local-unitary mapping is absent. Instead, we find that the Pauli spectrum mapping is generated by a non-invertible duality transformation. These results show that although the stabilizer Rényi entropy provides only a coarse diagnostic of phase transitions, the Pauli spectrum contains finer information about the exchange of string order sectors. Our findings demonstrate that quantum magic offers a complementary perspective for characterizing both gapped and gapless SPT phases.

We analyze minimum-error discrimination of two qubit dynamical processes generated by phase-covariant amplitude-damping Lindbladians in a single-use scenario. The optimization involves both the input probe, possibly entangled with an isolated ancilla, and the interrogation time. For unassisted probes we obtain a closed expression for the optimal trace-norm distinguishability at fixed time, with distinct interior and boundary branches. For entanglement-assisted probes, the common phase covariance of the two channels reduces the diamond-norm optimization to a one-parameter Schmidt family. The resulting formula gives transparent sufficient conditions for fixed-time entanglement advantage and separates this local advantage from advantage after global optimization over time. We exhibit examples in which the best unassisted strategy is approached only asymptotically, whereas an entangled probe achieves a strictly smaller error probability at finite time.

Polarization is fundamental degree of freedom of light, crucial for applications from imaging to quantum optics. Although numerous methods can spatially manipulate the polarization orientation, e.g., for generating vector beam, achieving simultaneous, spatially resolved control of both the orientation ({\psi}) and ellipticity (ḩi}) remains challenging. Here, we present an efficient and compact platform to generate spatially variant arbitrary polarization states, e.g., optical skyrmions, in free space, using cascaded spatially variant waveplates in a single silica glass plate via ultrafast laser direct writing. We propose two configurations: (1) a spatially variant half-waveplate (S-HWP) and followed by a quarter-waveplate (S-HWP); and (2) two cascaded spatially variant quarter-waveplates (S-QWPs). Design rules linking the target polarization parameters (orientation {\psi} and ellipticity ḩi}) to the fast-axis distributions enable spatially resolved arbitrary polarization control. Using these devices, we realize Néel-, Bloch-, and anti-skyrmions of different orders (e.g., second and fourth) and n-{\pi} textures (2{\pi} and 3{\pi}), with polarization-resolved measurements in excellent agreement with simulations. We further demonstrate 3 by 3 arrays comprising either identical or hybrid skyrmions. This approach enables the realization of spatially variant arbitrary polarization state and scalable skyrmion lattices.

AlGaN-based UVC LEDs (220-250 nm) suffer from poor hole confinement and strain-induced |Z>-band dominance at high Al content (>60%), leading to increased TM emission and reduced external quantum efficiency (EQE). While conventional k.p models combined with Schrodinger, Poisson, and drift-diffusion solvers are widely used to study optical transitions, they are computationally expensive. In this work, we apply the multiband Localization Landscape (LL) model, including the effect of strain, as an alternative that replaces the eigenvalue problem to efficiently capture quantum effects and carrier localization. Using the 3D multi-band LL model with the Wigner-Weyl formalism, we reproduce emission and absorption spectra trends similar to the results in 3D k.p calculations, but with significantly reduced simulation time. The polarization ratio also agrees well with published experimental results across a wide spectral range. Furthermore, we analyze electrical characteristics such as band structure, polarization switching, and carrier confinement under alloy fluctuations and strain. This multi-band LL-based approach provides a fast and reliable solution for understanding and optimizing UVC LED performance.

In the functional-integral formulation of Euclidean field theory, exact renormalization group (ERG) transformations are realized by functional-integral kernels. Unlike the ERG flow equations that describe infinitesimal ERG transformations, these ERG kernels explicitly depend on the global topology of the configuration space. This paper explores this topology dependence for multiply connected configuration spaces. We show that the ERG kernel is in general given by a weighted sum of kernels on its universal covering space, where the weight factors are determined by a one-dimensional representation of the fundamental group. These weight factors are shown never to be renormalized under the ERG. We also show that these factors can be interpreted as Aharonov-Bohm phases with respect to a background magnetic flux penetrating the infinite-dimensional configuration space. From this viewpoint, a normalization condition for ERG transformations corresponds to a flux-quantization condition, which is equivalent to the level-quantization condition for Wess-Zumino-Witten terms in nonlinear sigma models. Finally, we present an alternative gauge-equivalent form of the ERG flow equation that incorporates this topological information locally.

We construct reversible black hole heat engines in asymptotically flat spacetime using quasi-local gravitational thermodynamics. We enclose a Schwarzschild black hole in a finite spherical cavity and identify the working substance with the holographically dual thermal system on the cavity boundary. The surface pressure and the boundary area define a thermodynamic pressure-volume pair, while all coupling constants of the gravitational theory remain fixed. We derive exact efficiencies for the Carnot, Otto, Diesel, Brayton, and Stirling engines and compare them numerically. The non-Carnot efficiencies probe the quasi-local equations of state of the Schwarzschild black hole. Both the regenerative and non-regenerative Stirling efficiencies on the large black hole branch approach the Carnot value in the high-temperature limit, with regeneration reducing the leading deviation from the Carnot bound.

The relativistic vortex states of massive charged particles propagating in non-uniform axisymmetric electric field are studied. Starting from the stationary-state equation after the relativistic Foldy-Wouthuysen (FW) transformation and employing the paraxial approximation, the coupled evolution equations for the beam width, wavefront curvature, and Gouy phase are derived. The equations are solved numerically for a quadratic electrostatic potential, an immersion lens, and an einzel lens. The essential influence of the transverse field on beam evolution is demonstrated. The results provide a relativistic quantum framework for controlling accelerated vortex particle beams using electrostatic fields.

Galaxy groups and clusters trace the large-scale matter distribution, with their clustering usually interpreted mainly as a function of halo mass. Yet, at fixed mass, their baryonic properties retain information about halo growth, gas accretion, and feedback. The intrinsic scatter in X-ray luminosity and gas fraction suggests that X-ray-selected systems may not be a random subset of the halo population. If these observables correlate with halo assembly, they may trace secondary variations in halo bias. We test this using the Magneticum hydrodynamical simulation, measuring the clustering of systems selected by X-ray luminosity and gas fraction at fixed halo mass. We construct mass-matched subsamples by ranking halos in percentiles of X-ray luminosity and derive the linear halo-matter bias from the halo-matter cross-power spectrum. X-ray-bright halos are more strongly clustered than X-ray-faint halos at fixed mass. For the 84th-16th percentile split, we find $\Delta b_{\rm lin}=0.17\pm0.03$, corresponding to a $\sim17\%$ enhancement relative to the X-ray-faint sample. A 67th-33rd split gives a consistent signal, with $\Delta b_{\rm lin}=0.12\pm0.02$ and a $\sim12\%$ enhancement. The effect is strongest at group scales and negligible for cluster-size halos. Gas fraction shows an even stronger clustering dependence, with relative enhancements of $\sim39\%$ and $\sim26\%$ for the two percentile splits. This signal is present from $z\simeq2$, whereas X-ray luminosity becomes significant only at $z\simeq0.3$, once the gas thermodynamic state is more closely coupled to baryon retention. Matching halos by both mass and formation time reduces the large-scale bias difference to below $2\sigma$, indicating that formation time captures much of the signal. These results show that, in Magneticum, X-ray luminosity traces a baryonic manifestation of halo assembly bias beyond mass.

We use fully resolved nematohydrodynamic simulations to study deformation statistics of a passive nematic droplet in two-dimensional extensile active-nematic turbulence. We find that the droplet aspect ratio serves as a scalar probe of the active bath. Its increments show heavy-tailed distributions with dependence on the time lag, scale-free burst statistics and multiscaling structure functions which establish temporal intermittency. While the mean deformation increases with activity, normalized intermittency is strongest at lower activity. This suggests slower and more coherent bath forcing. When compared with translational and forcing-side fluctuations, it reveals a hierarchy of intermittency: shape is more weakly intermittent than translation and active-stress fluctuations, consistent with filtering by interfacial restoring forces. Power spectra show an extended near-$1/\omega$ regime for the maximal normal interface velocity, distinct from the steeper, approximately $1/\omega^{2}$ spectrum of the interfacial active stress. Soft inclusions thus reveal how interfacial restoring forces convert active forcing into bursty, scale-rich deformation dynamics.

The advancements in highly sensitive and powerful radio telescopes, including the Square Kilometre Array Observatory (SKAO) and its precursors, MeerKAT, ASKAP, MWA, and HERA, will enable us to create the deepest radio images of the sky. However, due to the sheer scale of the datasets, manually classifying and analyzing this data is computationally expensive, time-consuming, and laborious. Therefore, the development of automated algorithms to detect and classify complex morphological radio sources from large astronomical surveys is the need of the time. In this chapter, we examine the recent advancements and challenges in source-finding techniques triggered by the analysis of SKAO precursor data and the SKA Data Challenges, both in spectral and continuum modes, along with the growing demand for computational resources and automated source detection methods using machine learning (ML) algorithms for the identification and characterisation of new populations of sources, addressing their complex and diffuse morphologies, as well as transient nature. Additionally, we discuss the critical factors affecting the quality and limitations of automated source-finding techniques, including artefacts from residual continuum emission, sidelobes, radio frequency interference (RFI), technical failures, calibration issues, flagging methods and false positives. With the availability of the full operational phase of the SKAO, continued advancements in source detection algorithms and computational infrastructure will be essential to fully exploit its scientific potential.

The equal-charge branch of supersymmetric rotating AdS$_5$ black holes has $Q_1=Q_2=Q_3$. The corresponding microcanonical sector of the $\mathcal{N}=4$ superconformal index is obtained by projecting to equal charges, or equivalently by extracting the constant term in the two charge-difference fugacities. We prove that for the large-$N$ multigraviton sector the projected index factorizes exactly as \[ \mathcal{I}^{\rm eqQ}_\infty(x,p) =\prod_{k\ge1}(1-p^kx^{3k})(1-p^{-k}x^{3k}) \sum_{n\ge0}\mathsf{p}(n)^3x^{6n}, \] where $\mathsf{p}(n)$ is the partition function. This factorization gives, for every spin sector, an explicit onset energy below which the large-$N$ coefficient is zero. Exact $U(3)$ computations show that finite-rank coefficients can nevertheless appear at energies where the large-$N$ coefficient vanishes, including beyond the classical $U(3)$ black-hole bound. We also determine the full line $j=6J_R+6$. In particular, with $j^*(J_R)$ denoting this large-$N$ onset energy, \[ d_3^{\rm eqQ}(87,\tfrac{27}{2})=1, \qquad j^*(\tfrac{27}{2})-87=1554, \] and the first giant-graviton sector already contributes one unit at this point. All coefficients are coefficients of the $(-1)^F$-graded index, not positive degeneracies. The main conclusion is that the high-spin tail survives the exact equal-charge projection.

Circularly symmetric diffuse radio sources represent a recently recognized and rare class of extragalactic synchrotron-emitting structures whose physical origin remains uncertain. The currently known population is small, and the limited frequency coverage, sensitivity, and polarimetric information available from existing observations hinder robust discrimination among the various proposed formation scenarios. This chapter presents an overview of four representative circular diffuse sources featuring diverse morphologies, such as a horseshoe-shaped inner ring, circular diffuse emission surrounded by inner S/Z-shaped structures and a double-ring diffuse source. The angular sizes of these sources are in the range of 60-100 arcsec, similar to odd radio circles (ORCs). These systems illustrate the morphological diversity of circular diffuse radio emission and provide valuable clues to the physical processes responsible for their formation. The Square Kilometre Array Observatory (SKAO), with its unprecedented sensitivity, wide instantaneous bandwidth, sub-arcsecond imaging capability, and high-fidelity polarimetric performance, will significantly advance the study of these objects. SKAO surveys are expected to detect a substantially larger population of faint circular diffuse radio sources, enabling the first statistically meaningful studies of their occurrence, environments, and evolution. An expanded sample will allow investigations of their cosmological evolution and help determine whether their origin is linked to AGN feedback processes, episodic jet activity, galaxy interactions, or large-scale structure formation. This chapter summarizes the current observational knowledge of circular diffuse radio sources and describes how next-generation radio facilities, particularly the SKAO, will enable progress in understanding the origin and physical nature of these enigmatic radio structures.

Several observational and theoretical studies have suggested that the observed arm-length asymmetries in extragalactic radio sources are primarily driven by interactions between radio jets and an inhomogeneous ambient medium, although orientation effects may also contribute to the observed asymmetry. However, the observational evidence supporting these interpretations comes from only a small sample of FR II radio sources, in which the brighter hotspots are typically found on the side of the shorter jet arm. We aim to investigate the interactions between powerful jets and their surrounding environments in radio sources, with a particular focus on how these interactions shape the morphology and asymmetry of the radio lobes. The unprecedented sensitivity and angular resolution of the Square Kilometre Array Observatory (SKAO) will facilitate the discovery and detailed characterization of asymmetric radio sources across a wide range of physical scales and redshifts. Using a combination of 3D magnetohydrodynamic simulations and observational data from the SKAO, one can explore the influence of clumpy interstellar and intergalactic media on jet propagation and the resulting asymmetries in radio sources at various redshifts. The study will analyze how environmental factors, such as density and turbulence, decelerate jets, leading to observable asymmetries in smaller, higher-redshift sources. In this chapter, we review existing simulation and observational results on jet-environment interactions in radio galaxies and discuss how SKAO capabilities will further advance our understanding of AGN feedback and its role in shaping large-scale cosmic structure.

We present numerical three body simulations of a primordial black hole (PBH) encounter with the TOI 2796 system, which hosts a hot Jupiter. Over 100 days, we identify three outcomes: (i) ejection of the planet; (ii) a bound triple system (a approx. 1 au, P approx. 5 days); and (iii) capture of the planet by the PBH into a binary (0.0194 au, 15 days) that escapes the star. These results highlight the rich dynamical diversity of PBH encounters and their potential role in shaping planetary systems.

We show through theory and numerical experiments that a straightforward calculation of entropy production on short molecular dynamics trajectories allows estimating free-energy barriers and identifying optimal reaction coordinates of activated processes. To this aim, we perform an analysis based on stochastic energetics on a set of trajectories relaxing towards equilibrium from a same initial configuration, projected on different putative coordinates. After demonstrating the approach on simple benchmarks, we show that it is possible to estimate the free-energy barrier of a complex high-dimensional system (carbon nanoparticles in water) and to rank the quality of order parameters, in agreement with the committor probability. The results shed light on the entanglement between the second law, free-energy landscapes, reaction coordinates and kinetic rates.

Pulse profile modeling has proven to be a powerful technique for determining the mass and radius of neutron stars. To date, this method has been applied to a handful of millisecond pulsars observed by the Neutron Star Interior Composition Explorer (NICER). However, analyses of more millisecond pulsars are necessary to determine tight constraints on the equation of state of superdense matter. In this study, we present an analysis of the isolated, rotation-powered millisecond pulsar PSR J2124$-$3358 using the X-ray Pulse Simulation and Inference (X-PSI) package, a publicly available state-of-the-art code for neutron-star relativistic ray tracing and Bayesian parameter inference. We use NICER and Chandra observations of this pulsar, exploring different neutron star atmospheric compositions and different configurations of the hot polar caps responsible for the pulsed X-ray emission. Our analyses favor a helium atmospheric composition, plausibly originating from accretion and subsequent evaporation of a former hydrogen-depleted binary companion. For this composition, and given the faint nature of the source and the low signal-to-noise of the data sets, we obtain broad posterior distributions yielding a mass $M = 1.8\pm0.5\,M_\odot$ and an equatorial radius $R_{\mathrm{eq}} = 11.7^{+2.6}_{-3.0}$ km (medians and $68\%$ credible intervals), and infer a configuration consisting of two slightly non-antipodal hot spots. By contrast, when using a hydrogen atmosphere model, the mass and radius decrease by $\sim 0.5\,M_\odot$ and $\sim 1$ km, respectively. Future multiwavelength studies, particularly those incorporating radio and gamma-ray pulse-emission, may provide tighter constraints on the geometry and physical properties of this source.

We study the nonlinear Hall effect in Floquet-driven monolayer \(1T'\)-MoS\(_2\), a low-symmetry quantum spin Hall material whose tilted Dirac bands sustain an intrinsic Berry-curvature dipole without the need for strain or trigonal warping. We show that off-resonant circularly polarized light offers a way to control both the sign and the magnitude of the nonlinear Hall response through optically induced topological phase transitions using a Floquet effective Hamiltonian and nonlinear semiclassical transport theory. We show that the anisotropic crystal symmetry enforces a selection rule in which the Berry-curvature dipole elements satisfy $D_x\equiv0$, while a finite $D_y$ originates from the intrinsic band tilt. The Berry curvature is recreated in momentum space as the Floquet drive successively inverts individual spin-valley sectors, resulting in an identical sign reversal of the nonlinear Hall conductivity and the Berry-curvature dipole at each bulk gap closing. In contrast, tuning the band tilt modifies only the magnitude of the response without changing its sign, establishing the observed sign reversal as an unambiguous transport signature of genuine Floquet topological phase transitions. We further show that the nonlinear Hall response can be controlled by the driving strength, perpendicular electric field, Fermi energy, and temperature, providing multiple experimental knobs for observation. Our findings establish the sign of the nonlinear Hall response as a universal transport fingerprint of Floquet-engineered topology and point to monolayer \(1T'\)-MoS\(_2\) as a viable platform for all-electrical detection of nonequilibrium topological phases.

This article provides a self-contained bridge between classical vortex dynamics and the relativistic, subatomic domain of the Quark-Gluon Plasma (QGP) produced in ultra-relativistic heavy-ion collisions. While the QGP is widely studied for its near-perfect fluidity, we focus on its role as the most vortical medium in the Universe ($\omega \sim 10^{22}\text{ s}^{-1}$). The originality of our approach lies in isolating the explicit physical competition between non-linear vortex stretching and violent relativistic volumetric dilatation. By solving the covariant transport equations and tracking the comoving enstrophy density, we demonstrate that the explosive kinematics of the QGP provide an innate geometric shield that naturally regularizes the continuous flow, suppressing the self-amplification of vortex tubes before any microscopic viscosity is required. Furthermore, we connect this expansion phase back to the highly non-equilibrium initial state. We quantitatively predict that under a peripheral dipole initial topology, the global mid-rapidity hyperon polarization vanishes ($P_\Lambda \lesssim 10^{-4}$), establishing that the definitive signature of the QGP's rotation must be sought in azimuthal differential measurements within the LHC and RHIC experimental programs.

To probe the interplay between dark matter (DM) and non-linear electrodynamics (NED), we consider the Bardeen black hole (BH) surrounded by perfect fluid dark matter (PFDM). We first compute the effective potential governing the particle trajectory, and then, by imposing suitable conditions on the potential, examine the effects of DM and NED on the marginally bound orbit (MBO) and innermost stable circular orbit (ISCO). In this study, we confine the particle's trajectory to the equatorial plane. We then investigate periodic orbits around the Bardeen BH surrounded by PFDM (BPFDM BH), considering the rational number $q$ associated with each periodic orbit. We use the $(z,w,v)$ taxonomy, which is widely used to systematically organize periodic orbits. We examine the variation of $q$ with energy and angular momentum, and also the variation of the angular momentum and energy required for a specific $(z,w,v)$ configuration with the magnetic charge $g$ and DM parameter $\b$. Finally, with the help of the numerical "Kludge" method, we examine gravitational waveforms emitted from EMRIs where the central supermassive BH is modeled as a BPFDM BH. Our study reveals distinct signatures of NED and DM on orbital dynamics and gravitational waveforms.

We investigate the effects of isovalent Sb substitution at the As site in fluorine-doped PrFeAs1-xSbxO0.7F0.3 (x = 0 to 1.0) through structural, Raman spectroscopy, density functional theory (DFT), transport, magnetotransport, and magnetic measurements. The superconducting transition temperature decreases gradually from ~48 K for the parent compound to ~44 K up to x = 0.3, followed by a rapid suppression at higher Sb concentrations due to increasing disorder and secondary phase formation. Raman spectroscopy and DFT reveal lattice expansion and pronounced softening of pnictogen related vibrational modes upon Sb substitution. Magnetotransport measurements up to 9 T show enhanced upper critical fields and increased vortex activation energy for moderate Sb doping, indicating stronger vortex pinning. However, the critical current density remains low because of poor intergranular connectivity. The results demonstrate a crossover from an electronically tuned superconducting state to a disorder-dominated regime in isovalently substituted iron pnictides.

Antiferromagnets offer a promising route toward robust spintronic devices because of their compensated magnetic order and exchange-enhanced spin dynamics. Here, we demonstrate a spin-orbit torque (SOT)-driven antiferromagnetic oscillator based on a nanoconstriction patterned from a synthetic antiferromagnet (SAF). Spin-rectification spectroscopy reveals electrical excitation of both acoustic and optical SAF eigenmodes, whose field and frequency dependences are quantitatively described by an antiferromagnetic resonance model. In addition to these linear eigenmodes, we observe low-field spin-rectification peaks that emerge only above a threshold DC current near the spin-flop transition. Their current-polarity-dependent sign and locking to an injected RF frequency provide electrical spin-rectification signatures consistent with current-selected chiral self-oscillatory dynamics. Micromagnetic simulations reproduce the threshold excitation of SOT-driven self-oscillations and injection locking, while macrospin simulations predict stable and chaotic nonlinear dynamics within the same spin-flop region. We interpret the multi-peak, weakly RF-frequency-dependent responses as a qualitative signature of complex nonlinear dynamics. These results establish SAF nanoconstrictions as an experimentally accessible platform for studying current-driven antiferromagnetic-like oscillator dynamics and motivate future work on nonlinear spintronic devices for signal processing and reservoir-computing concepts.