Papers

Accurate measurements of interstellar dust mass are key to answering several astrophysical questions. A common method of obtaining the mass is to fit the far-infrared thermal emission of the dust with a modified blackbody model; however, this method is subject to several systematics. In particular, how temperature-dependent dust optical properties affect fit results has received little attention. We provide the first quantification of this effect based on experimental measurements of optical properties from the scientific literature. We created a grid of synthetic observations for variable-opacity dust and fitted it with a modified blackbody model; the difference between the input properties of synthetic observations and the values derived from the fit provides a measure of the bias induced by the temperature dependence. We find that fixing the value of the opacity power law index $\beta$ introduces a temperature-dependent bias on the fit, while keeping $\beta$ as a free parameter introduces a bias that depends mainly on the wavelength range used. For instance, depending on the properties of the observed object and on the choice of fit procedure, temperature dependence alone can induce an overestimate of 25-60% in dust masses at high redshift ($z \sim 8$). Our findings highlight the limitations of power laws as opacity models.

The development of techniques for simulating quantum systems using classical computers is a paramount task for two primary reasons: i) there exist configurations for which classical computers are remarkably effective and will continue to be so, and ii) exploring the limits of classical computation facilitates the identification of the regimes of competence for quantum computers. In this work, we present MPStab, a quantum circuit simulator based on a hybrid formalism combining stabilizers and tensor networks, recently introduced in Ref. [1]. We present the package, its core functionalities, and explore its performances in a few interesting simulation regimes.

We establish exact analytical thresholds and present a unified thermodynamic state-space representation for the regular Hayward black hole, resolving the full phase structure without reliance on numerical approximations. By evaluating the Hawking temperature, Helmholtz free energy, and heat capacity against the classical Schwarzschild baseline, we derive the exact geometric watershed for the zero-temperature extremal remnant at $r_h = \sqrt3l$, along with the exact Davies critical transition at $r_h = 3l$. Within the intermediate regime $\sqrt{3}l < r_h < 3l$, we uncover a distinct horizon bistability where two distinct horizon radii share identical free energy and temperature profiles. We demonstrate that the Davies singularity acts as a precise thermodynamic divide, separating a locally stable ($C_V > 0$) quantum Small Black Hole branch from an unstable ($C_V < 0$) Large Black Hole branch. Furthermore, we evaluate the exact integrated non-area law entropy at the critical turning point, yielding $S_{turn} = \pi l^2 \left[ \frac{63}{8} + 2\ln(8l^2) \right]$. Finally, we introduce a compact, 3-parameter thermodynamic state-space diagnostic that tracks the continuous evolution of regular black holes from classical thermal evaporation to cold remnant lock, offering a quantitative framework for quantum-gravity phenomenology.

Non-reciprocal interactions find broad applicability in non-equilibrium and living systems. Their canonical implementation involves asymmetric couplings between two entities, which generally induce spatio-temporal patterns and time-dependent steady states that break time-translational invariance, representing a clear deviation from equilibrium physics. Although their phenomenology is well understood, whether non-reciprocal interactions induce new universality classes, and if so, under what conditions, remains an open question. In the present work, we perform a field-theoretic renormalization group (RG) analysis of the dynamics of two non-reciprocally coupled $n$-vector order parameters possessing a $U(n)$ symmetry, generalizing previous results to order parameters with multiple components, a feature that has been shown to generate novel non-equilibrium critical behavior in certain non-reciprocal systems. To lowest order in $\epsilon = 4-d$, we find that the non-reciprocal coupling is RG-irrelevant, and the critical behavior is governed by the equilibrium fixed point of the Model A universality class of Hohenberg and Halperin with $2n$ vector components, even though the transition is into a non-equilibrium state. Our results demonstrate that non-reciprocity alone may not be sufficient to induce novel universality classes.

In this technical note we describe the main features of the mathematical theory of photomultiplier tube (PMT) calibration. Attention was paid to explain the various arguments and concepts in a simple and pedagogical manner that everybody understands. The basic operational principles of a PMT are discussed from a theoretical standpoint. The essential steps of its function (photoconversion, focusing, multiplication, etc.) are laid down together with the mathematical schemes necessary to model the charge output of a PMT when illuminated by a faint poissonian light source. In case of important omissions we direct the reader to some of the standard references. The most common numerical methods, used to calculate the charge amplification function $S_R(x)$, are also presented. As an example, we plot $S_R(x)$ utilizing a gamma function model for the single photoelectron (SPE) response and showcase its main characteristics. The basic techniques for gain calibration are also introduced, and we probed their precision using toy Monte Carlo data. Additionally, data from a Hamamatsu R1408 PMT were analyzed. Finally, we show how the presence of soft charge component can affect the results of gain determination. We conclude this report with some general comments regarding in situ calibration of large-scale detectors. We hope that this document can serve as a reference for students and young researchers that want to learn more about the theory of PMT calibration.

This work investigates deformable gas bubbles rising near a vertical wall in ultrapure water, focusing on how the position of the wall leading edge affects their near-wall dynamics. Two configurations are considered: (i) a wall extending from 11–25 bubble diameters below the bubble injection point, so that the bubble rises under the continuous influence of the boundary; and (ii) a wall whose leading edge is located 144 mm above the injector, corresponding to approximately 80–180 bubble diameters, allowing the bubble to reach its terminal velocity before entering the wall-bounded region. The results show that the wall leading-edge position influences both the transition from periodic bouncing (PB) to bouncing–tumbling–escaping (BTE) dynamics and the rebound frequency within the PB regime. When the wall leading edge is placed downstream, the onset of BTE occurs at smaller bubble sizes, corresponding simultaneously to lower Bond ($Bo$), Galilei ($Ga$), and Reynolds ($Re$) numbers. The Strouhal number ($St$) follows a similar decreasing trend in both configurations at low Bond numbers, but the two behaviours diverge for ($Bo \gtrsim 0.15$). For the PB regime, when the wall extends from the injector, $St$ approaches an approximately constant value of $St\simeq0.014$, whereas substantially lower values are measured for the downstream-wall configuration. The larger rebound amplitudes and longer return stages observed in the latter configuration account for lower frequencies. These findings indicate that the bubble dynamics depend not only on the conventional control parameters and wall separation, but also on the wall geometry and the associated pre-interaction bubble hydrodynamic history.

Square-net topological materials exhibit various interesting properties arising from the interplay of their structural diversity, topologically protected bands and different possible electronic features, including intrinsic magnetic ordering and superconductivity. However, little is known about the low-dimensional structures of these materials and their properties. Realization of low-dimensional topological square-net materials has the potential of enabling enhancement of their quantum behavior arising from quasi-compact 1D geometry and high surface-to-volume ratio, and their integration into functional devices. This work reports on the synthesis and properties of high-quality, single-crystal nanowires of Si square-net material TaSiAs. The chemical-vapor-transport produces TaSiAs nanowires that are chemically encapsulated with a thin dielectric shell of SiO2, enabling remarkable ambient stability and a pristine surface, which are critical for observing robust topologically protected surface states. Atomic-resolution structural analysis reveals a sharp core-shell interface, and a Si square-net lattice extending along the nanowire axis. These chemically protected nanowires allowed us to observe rich electrical and magnetotransport features, including 4 to 11 times lower room-temperature resistivity than the closest bulk analogues and non-saturating linear magnetoresistance, revealing topologically protected coherent surface transport. First-principles calculations show a wide-range (4 eV) linear band dispersion, alongside different Dirac cones that are protected by either symmorphic (C4) or non-symmorphic symmetries, predicting transport features consistent with our results. The findings demonstrate the unique properties of low-dimensional square-net topological materials and their potential applications, including next-generation interconnects, spintronic devices and quantum computing.

We show that retarded correlators in conformal field theories of scalar primary operators evaluated at finite temperature using $AdS/CFT$ scale anomalously at large light like momenta. The anomalous scaling depends on the curvature of the horizon. Setting the momenta equal to the frequency $\omega$, the retarded correlator for black holes with planar horizons scales as $\omega^{\frac{2}{d+2} (2\Delta - d) }$ as opposed to the scaling behaviour of $\omega^{2\Delta - d}$ expected by dimensional analysis at generic fixed momenta and large frequencies. $\Delta$ is the dimension of the primary and $d$, the number of space-time dimensions. For black holes with spherical and hyperbolic horizons when the frequency squared equals the Casimir along the horizon, the retarded correlator scales as $\omega^{\frac{2\Delta -d}{2} }$. We establish this using exact results in $d=2$, and a numerical analysis of the Heun equation for the $AdS_5$ planar black hole and finally using the WKB approximation in general $d$. The exact result for black holes with hyperbolic horizon as well as the analysis at large $d$ provides additional checks for the anomalous scaling behaviour. Finally we evaluate the anomalous scaling exponent for the stress tensor correlator in all its 3 channels.

In this work, we demonstrate an ultra-narrow linewidth self-injection locked distributed feedback (DFB) diode laser emitting at 452 nm, achieving an intrinsic linewidth of 170 Hz with a fiber output power of 11 mW. The linewidth reduction of the DFB laser is obtained thanks to the coupling with an external cavity based on a fiber Bragg grating (FBG). Experimental results demonstrate excellent agreement with our theoretical modeling of the self-injection dynamics. Furthermore, the tuning capabilities of the system are characterized, with tunability achieved via current modulation, yielding a tuning efficiency of 300 MHz/mA over a continuous mode-hop-free range of 600 MHz. This architecture offers a robust pathway toward an integration within a compact package. Ultimately, such compact, stable, and frequency-tunable visible light sources are key for integrated optical atomic clocks and underwater lidar application.

Cold polar molecules offer fascinating prospects for ultracold chemistry and quantum physics, including new platforms for quantum simulation or computation. However, their inherent collision properties remain largely unknown. It has proven extremely hard to experimentally probe collisions between two dipolar molecules at sufficiently low energies and high precision, as it appears fundamentally impossible to merge two beams of molecules with significant dipole moments. Here we report measurements of state-to-state cross sections for collisions between ammonia isotopologues at energies between 0.3 and 100 cm$^{-1}$ using a novel beam merger. We experimentally observed a local maximum in the cross sections that indicates the effective dipole moments can switch off at low collision energies. Scattering calculations reproduced this maximum in good agreement and explained the observed scaling with the parity splitting energies in the molecular energy level structures. Measurements of the correlated energy transfer in both collision partners yielded direct evidence of the suppression of the dipole-dipole interaction at low energies. Our results demonstrate how collisions between an important class of polar molecules evolve from the high temperature limit towards the ultracold regime in a counterintuitive way, have major consequences for the feasibility of future experiments and the interpretation of previous work, and offer distinctive opportunities to control cold molecular collisions with external fields.

We study the partition function of Abelian $BF$ theory with an axial gauge fixing condition given by a Morse–Smale vector field, and we show that it recovers the Milnor metric on the determinant line on the twisted cohomology of the manifold. To do this we use the Batalin–Vilkovisky formalism and, in particular, a BV pushforward to cohomology in two steps. In this context, the Milnor metric serves as the generalisation of the Ruelle dynamical zeta function evaluated at zero for systems containing both closed orbits and critical points. This, together with a classic result due to Schwarz on the partition function of $BF$ theory in the Lorenz gauge, provides a field-theoretic realisation of Fried's conjecture, which is true for Morse–Smale flows.

Relativistic particle beams propagating through dense ambient plasmas are susceptible to streaming instabilities that can govern the system dynamics in various astrophysical and laboratory settings. For an unmagnetized, collisionless plasma pervaded by a dilute, cold relativistic beam, the dominant instabilities are the quasielectrostatic, oblique two-stream (OTSI) and the essentially magnetic, current filamentation instability (CFI). While their linear and nonlinear properties have been researched for decades, most treatments assume unbounded, uniform systems and thus predict purely temporal instability growth. This assumption, however, is questionable for realistic configurations where a bounded beam continuously encounters fresh plasma. This feature causes instabilities to grow in a spatiotemporal manner. Whereas spatiotemporal perturbative treatments of streaming instabilities were derived as early as the 1960s, only recently have the spatiotemporal regimes of OTSI and CFI been addressed theoretically. Yet these models are restricted to a specific instability class, and hence cannot describe the competition between spatiotemporal OTSI and CFI. In this work, we present a unified, fully electromagnetic quasi-static model of all unstable modes arising throughout the beam. By not adopting the slowly varying envelope approximation (SVEA), we find that a previously unreported spatiotemporal CFI actually prevails near the front, precisely where the SVEA fails, and is only superseded by OTSI further back in the beam. Furthermore, we demonstrate that our model also captures the growth of the self-modulation and hosing instabilities excited by long, narrow beams. Comparisons with particle-in-cell simulations confirm the validity of the quasistatic approach for modeling streaming plasma instabilities triggered by relativistic dilute beams.

Do two Hamiltonians related by a non-invertible transformation necessarily share the same finite-temperature phase diagram? For a cluster-model interpolation $H(s)$ and its Kennedy–Tasaki dual $\tilde H(s)$, the map is a partial isometry and equates only their all-plus-sector partition functions. In one dimension, thermal order is forbidden on both sides, leaving only the common zero-temperature transition at $s=\tfrac12$. In three dimensions, however, the inequivalence is exact already at $s=0$: the cluster model has an analytic paramagnetic free energy, whereas its dual $\mathbb Z_2$ gauge theory has a deconfinement transition at $T_c\approx1.31$. Quantum Monte Carlo shows that the mismatch occupies a finite window of the interpolation, marked by a self-dual frozen wedge on the cluster side and a deconfined dome on the gauge side; once both close the two phase diagrams agree again, coinciding over the entire remaining interval up to the shared trivial endpoint $s=1$.

We present the first scientific results delivered by the upgraded THD2 high-contrast imaging testbed. We report two advances enabled by its improved stability and broadband performance. First, for the Roman Space Telescope, we demonstrate that Gaussian-shaped diversity probes outperform the baseline sinc probes by reducing non-linearities, supporting higher probe amplitudes, and improving electric field estimation efficiency. These results have led to their prioritization as an enhanced early observation for Roman. Second, within ESA's SUPPPPRESS project, we test new polarization-independent Vector Vortex Coronagraphs and design them to high-contrast performance approaching 1e-10 over a 20% bandwidth. We assess their behavior in narrow- and broadband light with active focal-plane wavefront control. Together, these results show how THD2 strengthens Europe's capability in high-contrast imaging, providing a unique platform reaching contrasts of 1e-8 to 1e-9 for developing next-generation coronagraphic technologies.

The persistence of ferromagnetic long-range order in monolayers of the van der Waals semiconductor CrI$_3$ opens new routes for spintronic applications based on two-dimensional quantum magnets. In the fabrication of such devices, the constituent materials inevitably experience anisotropic strain, which modifies their intrinsic electronic properties. At the same time, strain can serve as a powerful tuning parameter, driving the material to desired regimes. While several theoretical studies have investigated the effect of biaxial in-plane strain on CrI$_3$ numerically, experiments are widely limited to the application of hydrostatic pressure. Here, we perform high-resolution magnetostriction experiments on bulk CrI$_3$ samples, and ab-initio-based magnetoelastic calculations, to elucidate the role of uniaxial lattice strain on the magnetic properties. Our data show that magnetostriction in CrI$_3$ is unexpectedly sensitive to surface effects, which enables us to investigate the influence of in-plane and out-of-plane strain separately, in both the bulk ferromagnetic (BFM) phase emerging at $T_{\rm C}=61\,\mathrm{K}$ and the surface antiferromagnetic (SAFM) phase below $T^* \simeq 50\,\mathrm{K}$. In particular, we quantify the uniaxial strain dependence of the surface interlayer coupling $J^{\rm SAFM}_{\perp}$ and the surface spin-flip field $B^*$, which drastically exceed the strain effects in the BFM phase by a factor of $\sim 30$. The large magnetostrictive response allows us to study the magnetoelastic coupling in few-layer CrI$_3$ through experiments on bulk single crystals, without requiring exfoliation.

Plasma streaming instabilities excited by relativistic charged particle beams play a pivotal role in astrophysical and laboratory environments. Their numerical study, however, is challenged by the disparity in spatiotemporal scales between the background plasma and beam particles, which can differ by several orders of magnitude for tenuous, ultrarelativistic beams. Here, we exploit the quasistatic approximation (QSA) to develop a new theoretical framework capable of capturing the full unstable spectrum in the spatiotemporal regime relevant for beams that continuously encounter unperturbed plasma at their leading edge. Within this linear, fully electromagnetic model, we uncover a previously unreported spatiotemporal evolution of the current filamentation instability and elucidate its interplay with the oblique two-stream instability, predicting the dominance of filamentation in the vicinity of the beam front. The good agreement between theory, kinetic particle-in-cell (PIC) simulations, and QSA-based PIC simulations validates the robustness of the approach. By pushing QSA-based PIC simulations to extremely dilute electron-positron beams, such as those found in blazar jets, we demonstrate their unique ability to capture the rich nonlinear dynamics of streaming instabilities in parameter regimes previously inaccessible to kinetic simulations.

We investigate the cluster structure of $\alpha+{}^2n+{}^2n$ in $^8\mathrm{He}(0_2^+)$ and compare it with those of $2\alpha+{}^2n$ in $^{10}\mathrm{Be}(0_2^+)$ and $3\alpha$ in $^{12}\mathrm{C}(0_2^+)$ to understand the emergence mechanism of the 3-body cluster gas states. We apply an extended cluster model combined with cluster breaking components in a microscopic framework using effective nuclear forces based on nucleon degrees of freedom including the antisymmetrization between nucleons. In detailed analysis of the 3-body cluster structures of excited $0^+$ states, it is shown that $^8\mathrm{He}(0_2^+)$ exhibits 3-body cluster gas feature of $\alpha+{}^2n+{}^2n$ similar to $^{12}\mathrm{C}$ but contains significant mixing of a 2-body-like $(\alpha+{}^2n)+{}^2n$ component. We discuss cluster structures of $^8\mathrm{He}(0_2^+)$ and $^{12}\mathrm{C}(0_2^+)$ from the point of view of inter-cluster energies of ${}^2n \text{-} {}^2n$ and $\alpha\text{-}{}^2n$ in comparison with the $\alpha \text{-} \alpha$ energies and find that the origin for the 2-body-like $(\alpha+{}^2n)+{}^2n$ mixing is the unbalance of the $\alpha\text{-}{}^2n$ and ${}^2n \text{-} {}^2n$ energies, in which Pauli effects play an essential role through the kinetic energy loss and internal potential energy loss of clusters. We clarify the emergence mechanism of the 3-body cluster gas state in excited $0^+$ states of $^8\mathrm{He}$ and $^{12}\mathrm{C}$ systems. The balance of inter-cluster interactions is essential for the appearance of 3-body cluster gas states. Microscopic effects, i.e., the Pauli effects of nucleons between clusters play a crucial role in cluster structures of excited $0^+$ states.

Understanding how the breaking of reciprocity influences thermal flows and microscopic thermodynamic processes such as refrigeration and energy conversion is of broad current interest. We report experimental measurements of thermal flows and refrigeration in nanomechanical resonator networks in which nonreciprocity is controlled through an optically-induced synthetic magnetic flux. Time-modulated optomechanical interactions allow controlled coupling, gauge fields, and refrigeration processes through nanomechanical frequency conversion. We quantify nonequilibrium heat flows between resonators coupled to dissipative baths of different occupation and image heat and effective temperature in networks through measuring correlations of fluctuations. Synthetic magnetism is shown to imprint chirality on thermal fluctuations in a loop of resonators, leading to pronounced chiral flows with different handedness in distinct frequency bands. We find that the heat flows in a non-equilibrium system are tuned by the synthetic magnetic flux, which redistributes energy in the thermal steady-state. Specifically, we illustrate how nonreciprocity enhances the refrigeration of a resonator in the strong coupling regime, reducing its temperature below the bound that applies to time-reversal symmetric networks. These results experimentally demonstrate the impact of nonreciprocity on thermodynamic machines, and provide new methods to characterize them at the microscopic level.

The quantum metric integral (QMI) in two-dimensional (2D) systems is conventionally bounded from below by the Chern number. For systems with zero Chern number or identically vanishing Berry curvature, however, this bound becomes trivial and provides no useful geometric constraints. Here, we develop a dimension-reduction framework that decomposes the 2D QMI into lower-dimensional components in a nested-loop way. With this method, we establish a nonzero lower bound on the QMI arising from one-dimensional topological obstructions even when the conventional 2D topology is trivial. We explicitly demonstrate this mechanism in a tilted 2D Su-Schrieffer-Heeger model and an anisotropic Wilson-Dirac model with chiral symmetry. The resulting lower bounds of QMI are determined by the quantized Wannier bands along two different directions. We further investigate the quantum geometry in higher-order topological phases following the same strategy. By introducing Wannier-band basis obtained from the nested Wilson loop, we demonstrate that the Wannier-band QMI is bounded from below by the higher-order topological invariant, e.g. the quadrupole moment in Benalcazar-Bernevig-Hughes model. Our results establish nonzero lower bounds on QMI from a dimension-reduction framework, thereby generalizing the fundamental relation between quantum geometry and topology.

The ALICE collaboration plans a completely new tracking detector based on silicon MAPS technology manufactured in the 65 nm production node as part of the ALICE~3 upgrade during Long Shutdown 4 of the LHC. The size of the whole active area is planned to be 50 m$^2$, with the Outer Tracker spanning 45 m$^2$. To reach the material budget target of less than 1% $X_0$ per layer, open questions like cooling solutions, mechanical structures and electronics have to be answered. A simple sensor prototype MADHAT (Mechanical Assessment Design for Heat And Thermal solutions), mechanically identical to the final sensor, but with integrated heating elements and temperature probes, was developed to study the temperature distribution in the final detector assembly and to assess different mechanical designs of the circuit board that houses the sensor. Furthermore, it will be used to practice the industrialization of the whole mass-production, including the assembly of FPCs with external companies. In this paper, we present the design of the MADHAT, a prototype readout module and show the results of first measurements.

We study the concentration of the field between two nearly touching high-index dielectric resonators in three dimensions. The model is a scalar Helmholtz transmission problem in the resonant regime, wherein the wavelength inside the resonators of the same order as their typical diameter. The material contrast enters only a lower-order term of the equation and not its principal part. As a consequence, the gradient of the field stays bounded independently of the distance separating the particles, and does not blow up. Nevertheless, simulations and experiments show that the gradient still concentrates in the gap: as the particles approach, it grows like the inverse of their separation over an intermediate range of distances and then saturates once they are very close. We explain this pre-asymptotic effect through a weak-coupling regime, in which the resonant modes of the pair are perturbations of the modes of each isolated particle. When such a mode keeps a nonzero contrast between the two facing boundaries, a mean value argument across the gap accounts for the growth of the gradient; this requires strengthening the standard spectral perturbation estimates from an average to a pointwise control. The growth stops once the interaction between the particles is no longer weak and the perturbation theory fails. Numerical experiments confirm the transition from amplification to saturation.

Motivated by the recent observation of the pseudoscalar toponium ${\eta}_{t}$ at the LHC and by the ongoing interest in its properties, we phenomenologically investigate the ${\eta}_{t}$ ${\to}$ $W^{+}W^{-}$ process, one of the characteristic decays of toponium ${\eta}_{t}$. The branching ratio for the ${\eta}_{t}$ ${\to}$ $W^{+}W^{-}$ decay is estimated with two scenarios of the decay constant $f_{{\eta}_{t}}$. It is found that tens of dilepton events from the cascade decays, ${\eta}_{t}$ ${\to}$ $W^{+}W^{-}$ ${\to}$ ${\ell}^{-}\bar{\nu}_{\ell}{\ell}^{{\prime}+}{\nu}_{{\ell}^{\prime}}$ with ${\ell}$, ${\ell}^{\prime}$ $=$ $e$ and ${\mu}$, could be experimentally observed, when considering the realistic identification efficiency of the charged lepton and assuming more than $3{\times}10^{7}$ ${\eta}_{t}$ events available at the future HL-LHC. We propose searching for ${\eta}_{t}$ via the ${\eta}_{t}$ ${\to}$ $W^{+}W^{-}$ ${\to}$ ${\ell}^{-}\bar{\nu}_{\ell}{\ell}^{{\prime}+}{\nu}_{{\ell}^{\prime}}$ channel, which features no $b$-jets and clean dilepton signatures, thus offering a complementary and potentially more sensitive probe.

An intermediate-mass black hole (IMBH) hidden in our Galactic Center (GC) may explain the puzzling observations of the stellar distribution around Sagittarius A* (Sgr A*), the supermassive black hole (SMBH) in the GC. Future observations with the next-generation radio telescopes, such as the SKA, are promising to discover pulsars orbiting around Sgr A*, and thus provide the possibility of constraining the hidden IMBH with pulsar timing. We study the detectability of a third-body, the IMBH, in the pulsar-SMBH system based on radio timing observation. We find that the pulsar-SMBH system is very sensitive to such a third-body perturbation and can be used to put stringent constraints on the existence of the IMBH. Even under strong perturbations caused by the complex GC astrophysical environments, timing observation will still complement the existing observational constraints.

Exact synthesis is a key infrastructure in quantum circuit synthesis and optimization, which provides optimal implementations of small circuit shards and is widely used as a circuit re-synthesis optimization kernel. However, existing quantum exact synthesis methods suffer from encoding overhead, memory bottlenecks, and poor parallel scalability. In this work, we introduce a parallel exact synthesis framework for CNOT and phase polynomial circuits based on the semi-tensor product (STP) theory of matrices that avoids these issues. The algorithm contains two stages: it first enumerates candidate circuit topologies, and then instantiates each topology by determining the control and target qubit of its partial gates via a STP-based circuit solver. In the second stage, circuit topologies are encoded as canonical STP expressions, and the CNOT gates are synthesized through right-to-left STP matrix factorization that progressively eliminates infeasible gate decisions. In the framework, topology enumeration and the subsequent solving process are independent across different topologies, and can be naturally parallelized. Despite the NP-hardness of the problem, our algorithm yields up to $12.8\times$ parallel speedup with 32 workers, whereas the parallel speedups of existing SAT-based methods remain below $5\times$ with the same worker budget. On randomly generated synthesis targets, the proposed algorithm is typically $100$-$1000\times$ faster than the SAT-based approach on small and moderately difficult instances, and remains competitive for more difficult instances. When integrated in a real-world circuit optimization workflow, our algorithm achieves a median speedup of $3.41\times$ on the QASMBench benchmark.

We consider one-frequency quasiperiodic Schrödinger operators \[ (H_{v,\alpha,\theta}u)(n) = u(n+1)+u(n-1) + v(\theta+n\alpha)u(n) \] acting on $\ell^2(\mathbb Z)$, where $\alpha\notin\mathbb Q$ and $v\in C^2(\mathbb T,\mathbb R)$ is an even function. We develop a new Gordon-type method that exploits approximate repetitions and palindromic symmetries simultaneously. Denote by $L(E)$ the Lyapunov exponent and let \[\beta(\alpha) = \limsup_{|k|\to\infty} -\frac{\log\|k\alpha\|_{\mathbb R/\mathbb Z}}{|k|}. \] We prove that, for every completely resonant phase $2\theta\in\alpha\mathbb Z+\mathbb Z$, $E$ cannot be an eigenvalue if $L(E)<2\beta(\alpha)$. As an application, consider the almost Mathieu operator \[ (H_{\lambda,\alpha,\theta}u)(n) = u(n+1)+u(n-1) + 2\lambda\cos\bigl(2\pi(\theta+n\alpha)\bigr)u(n). \] We show that if $2\theta\in\alpha\mathbb Z+\mathbb Z$ and $1<|\lambda|<e^{2\beta(\alpha)}$, then $H_{\lambda,\alpha,\theta}$ has purely singular continuous spectrum. This resolves the remaining absence-of-eigenvalues part of a conjecture of Avila and Jitomirskaya concerning the sharp spectral transition for completely resonant phases.

A gravity-aligned vertical electron-positron linear collider is proposed as a concept to break the cost-and-scale impasse that confronts conventional horizontal Higgs factories. The accelerating axis is oriented along the local gravitational field inside a single deep vertical shaft. Positrons are injected downward from the surface while electrons are accelerated upward from the bottom, the two beams meeting at an interaction point located deep underground. Targeting a staged center-of-mass energy in the Higgs factory range (250-500 GeV), this concept assumes high-gradient, high-efficiency, normal-conducting accelerating structures operated at cryogenic temperature together with a two-beam power-delivery scheme. It can be designed to reuse the existing KEK/SuperKEKB accelerator complex at the KEK Tsukuba Campus. We discuss the advantages of the vertical orientation, namely a small surface footprint, intrinsic azimuthal symmetry of the gravity load, deep vibration isolation of the collision point, gravity-assisted cryogenics, a natural vertical alignment reference, a cosmically quiet deep interaction point, an opportunity for on-site electricity self-sufficiency, and a unique opportunity in social/industrial evaluation, as well as the principal disadvantages and challenges, including the required accelerating gradient and the construction of a kilometers-deep shaft. Using only publicly available information, we argue that excavating a shaft with a depth of ~3 km is feasible at a geologically favorable site. This paper is deliberately concept-level and is intended to motivate technological innovation, feasibility studies, and the exploration of possible new channels for Beyond-Standard-Model searches through vertical collisions.

We propose a four-terminal, X-shaped chiral Majorana interferometer with a central floating superconducting island, enabling the direct detection of the non-Abelian statistics of Ising anyons via the linear-response DC conductance tensor in charge transport experiments. Here, Ising anyons are realizable as edge vortices nucleated at Josephson line junctions defining the superconducting island, where both edge-vortex and Majorana-fermion tunneling processes can occur. We show that in such a multi-terminal Majorana interferometer, both the vacuum and the fermionic fusion channel for Ising anyons are possible. This is in contrast to two-arm interferometers, where only the vacuum fusion channel is accessible and the DC conductance contribution from edge vortices always vanishes. Using a low-energy effective theory derived via chiral bosonization, we find that in the X-shaped interferometer, the DC conductance tensor is completely isotropic, yielding a non-zero conductance when simultaneous edge-vortex and Majorana tunneling activates the fermionic fusion channel. Apart from conductance oscillations in a gate-tunable charge parameter, which display an offset related to the anyon topological spin, measuring a finite conductance can already provide direct evidence for non-Abelian statistics in this geometry.

We construct a finite-energy Wigner counterexample and a concrete one-parameter family of Gaussian-regularised Bernoulli entry laws yielding counterexamples to the conjectural dimensional monotonicity of the quadratically penalised logarithmic energy for mean empirical spectral distributions by Chafaï, Dadoun, and Youssef.

We give a new criterion to show optimality of Hardy weights for general operators on graphs via the supersolution construction. For Laplacians on graphs without killing terms this always gives rise to an optimal Hardy weight via the Green's function without any further assumptions. Furthermore, in contrast to earlier results, our result is not restricted to locally finite graphs. This allows us in particular to obtain optimal Hardy weights for the fractional Laplacian on general graphs. For the fractional Laplacian on the Euclidean lattice, we then obtain an optimal Hardy weight with the constant and asymptotics as it is expected from the continuous setting.

Here we show that an autocatalytic reaction network can exhibit dynamic hysteresis as a result of the competition between its intrinsic relaxation time scale and that of the periodic drive. The autocatalytic reaction steps generate bistability in the concentration of the autocatalytic species, and periodic pumping of the product species provides the external drive. Hysteresis arises from the lag between the concentration response of the autocatalytic species and the external periodic drive. The resulting hysteresis-loop area quantifies the extent of the system's hysteretic response. Using the periodically driven Schlögl model as a representative bistable chemical system, we use this loop area to determine how the magnitude of the hysteretic response is controlled by the driving protocol, intrinsic fluctuations, and the size of the system. Varying the driving frequency and the strength of the fluctuations causes a turnover of the hysteresis loop area, whereas the area changes monotonically with driving amplitude and system size. These trends identify the driving protocol and fluctuation strength as primary controls on the magnitude of dynamic hysteresis. In contrast to stochastic resonance, which is typically associated with weak periodic forcing and noise-assisted amplification, dynamic hysteresis can characterize the reaction-system response over a wider range of external control conditions. We further show that the delayed concentration response is mirrored in Shannon entropy and in the total entropy production rate, connecting dynamic hysteresis to information-theoretic and stochastic-thermodynamic measures of irreversibility. Overall, we identify and interpret the role of the controlling factors in chemical dynamic hysteresis and suggest implications for efficient chemical logic gates and eventually, chemical computers.