Nuclear Theory
Electron scattering and the distribution of electric charge and magnetization inside nuclei
Alex Gnech, Lorenzo Andreoli, Graham Chambers-Wall et al. (+2 more)
How are the electric and
magnetic distributions carried by
protons and
neutrons arranged inside an atomic
nucleus? One of the most reliable ways to answer this question is to scatter electrons from
nuclei. Because the electromagnetic interaction is well understood and electron beams can be prepared and detected with high precision, electron scattering acts as a microscope that probes
nuclear structure across a wide range of length scales. In this chapter we discuss how electron-
nucleus scattering measurements are related to the distribution of the electric charge and magnetization inside
nuclei, and what these distributions reveal about
nuclear structure. We present this discussion through modern theoretical tools based on ab initio approaches, which describe
nuclei as interacting many-body
quantum systems, with many-nucleon interactions and electroweak currents derived from first principles.
Read the full abstract ▾
All authors Alex Gnech, Lorenzo Andreoli, Graham Chambers-Wall, Garrett King, Saori Pastore
Quantum Physics
A Correlation Aware Quantum Feature Map for Variational Quantum Classification
Murat Kurt
Quantum machine learning has emerged as a promising research area for learning complex data patterns. However, most existing
quantum feature maps employ fixed encoding strategies that do not explicitly consider the relationships among features within a
dataset. In this study, we propose a Correlation Aware
Quantum Feature Map (CAQFM) which integrates feature dependencies into the
quantum encoding process. The proposed approach utilizes Pearson, Spearman, Kendall Tau, Mutual Information, and Distance Correlation measures to identify relationships among features. Dependencies exceeding a predefined threshold are incorporated into the
quantum circuit through controlled
quantum gates, enabling the construction of richer
quantum representations that better reflect the underlying structure of the data. The proposed method is evaluated using a Variational
Quantum Classifier (VQC) on three
benchmark datasets, namely breast cancer diagnosis, credit default prediction, and student placement classification. Simulation results demonstrate that correlation based
quantum encoding can improve classification performance compared to conventional encoding strategies. In particular, the Spearman and Kendall Tau based CAQFM variants achieved the highest predictive performance and consistently outperformed standard
quantum feature maps. The findings indicate that incorporating dependency information from classical data into
quantum feature maps facilitates the generation of more discriminative
quantum representations and enhances the effectiveness of variational
quantum classifiers.
Read the full abstract ▾
Quantum Gases
The moving Fermi polaron
Johanna Hennebichler, Ruben Erlenstedt, Erich Dobler et al. (+5 more)
The
Fermi polaron, formed by an
impurity interacting with a surrounding
Fermi sea, exemplifies the canonical quasiparticle concept as a cornerstone in our description of
quantum many-body systems across a wide range of energy scales. Experiments on atomic
quantum gases have provided profound insights into the universal nature of the
Fermi polaron. While most previous studies have focused on the case of zero
impurity momentum, finite-momentum properties have remained largely uncharted. Here, we investigate the moving
Fermi polaron by combining a novel Raman acceleration scheme with high-precision
radio-frequency spectroscopy, exploring the quasiparticle dispersion relation over a wide range of momenta. We compare our measurements of energy shifts and spectral linewidths with a microscopic theory and reach quantitative agreement for all momenta. For low momenta, we find the energy of the moving polaron to be fully consistent with the
Fermi liquid picture of a dressed particle with a constant effective mass. At high momenta, the polaron approaches the behavior of a weakly interacting bare particle, featuring small energy shifts and weak broadening. For intermediate momenta, broadening is generally larger and, most strikingly, the behavior differs for attractive and repulsive polarons. While the repulsive polaron exhibits a smooth connection between both regimes along with a monotonic change of the energy shift, the attractive case shows a peculiar non-monotonic behavior. With increasing momentum, the attractive polaron enters a regime where its energy deviates from the constant effective mass expression and broadening suddenly increases. By comparing this observation with theory, we show that this abrupt behavior coincides with the attractive polaron entering a molecule-hole continuum, where it is no longer the ground state. We interpret this as a motion-induced polaron-molecule transition.
Read the full abstract ▾
All authors Johanna Hennebichler, Ruben Erlenstedt, Erich Dobler, Cosetta Baroni, Rudolf Grimm, Matteo Caldara, Georg Bruun, Pietro Massignan
Lattice Field Theory
SU(2) gauge theory with fermions on a semi-simple cubic lattice
Randy Lewis, Shidsa Pourbakhsh, Arnab Pradhan et al. (+1 more)
A practical
Hamiltonian approach to
lattice gauge theories would provide access to several important areas of phenomenology that have been beyond the reach of conventional
lattice methods.
Quantum computers seem to be a natural platform for this approach. With near-term
quantum computers in mind, our work considers a three-dimensional spatial
lattice that can host
fermions and non-Abelian gauge fields while needing fewer
qubits than a simple cubic
lattice. Specifically, the semi-simple cubic (ssc)
lattice is obtained by removing half of the gauge links from a standard cubic
lattice in such a way that every vertex becomes trivalent, which streamlines the handling of Gauss's law. The ssc
lattice is topologically equivalent to the triamond
lattice but, because the gauge links at each vertex span all three directions, the ssc
lattice can accommodate a local
fermion derivative. The case of staggered
fermions with SU(2) gauge fields is presented here.
Read the full abstract ▾
All authors Randy Lewis, Shidsa Pourbakhsh, Arnab Pradhan, Lance Siquioco
High Energy Physics (Theory)
Asymptotic limits of constrained instantons
Benjamin Elder, Kinga Gawrych and Arttu Rajantie
We revisit the topic of false
vacuum decay in field theory. We focus on a toy model of a real massive scalar field with an unstable quartic potential. This model has a false
vacuum, and decay out of the false
vacuum can be described via the method of constrained instantons, which work by introducing a constraint on the path integral. We identify and develop three different asymptotic limits which enable analytic construction of approximate {constrained} solutions. The first, in which the constrained solution is small compared to the inverse mass of the scalar field, is an application of the perturbative methods of Affleck, although we re-derive the main results and identify several terms which were previously neglected. Second, for very large constrained solutions we adapt the thin-wall approximation of Coleman. However, we find that the large instanton limit does not always exist. In this case we identify another useful limit, in which the Lagrange multiplier used to implement the constraint is large. In this limit, the solution's scaling with the parameters may be found via dimensional analysis and an exact solution is obtained with a single numerical computation.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
A thermodynamic uncertainty relation for (hybrid) N–S coherent conductors
Sergi Vidal and Rosa Lopez
Thermodynamic uncertainty relations establish fundamental bounds between current fluctuations and
entropy production in nonequilibrium systems. In hybrid normal superconducting conductors, transport is governed by the coexistence of quasiparticle transmission and Andreev reflection, where electron hole conversion transfers charge through the superconducting condensate. Using the Anantram Datta scattering formalism, we decompose the charge current and zero-frequency noise into Andreev, quasiparticle, and interference contributions. Although the interference term prevents a simple additive bound at the level of individual noise components, we show that the nonequilibrium excess noise admits a positive representation. This allows us to prove a hybrid
quantum thermodynamic uncertainty relation valid for an arbitrary real superconducting gap. Our result extends the pure Andreev
quantum TUR to regimes where quasiparticle and Andreev processes coexist, clarifying how superconducting coherence reshapes current fluctuations while preserving a universal dissipation precision constraint in hybrid
quantum conductors.
Read the full abstract ▾
Fluid Dynamics
Revisiting creeping viscoelastic cross-slot flow: Global linear stability and structural sensitivity analyses
Kun Zhang, Zhanwen Wang and Lailai Zhu
The viscoelastic instability of cross-slot flow was first observed experimentally almost half a century ago and reproduced numerically two decades ago, yet its physical origin remains unresolved. We revisit this problem for two-dimensional creeping flow of Oldroyd-B fluid by combining direct numerical simulations, global stability analysis, structural sensitivity analysis, and energy-budget analysis. Our simulations reproduce the canonical pitchfork bifurcation, and the stability analysis consistently predicts the threshold and perturbation growth rates. The leading eigenmode consists of a
chiral velocity–stress perturbation that tilts and rotates the birefringent strand generated by the extensional flow. Structural sensitivity and energy-budget analyses identify narrow high-extension-rate ridges within the extensional flow as both the spatial core and energetic source of the instability. In these ridges, the stress-based wavemaker co-localizes with large positive disturbance polymeric stress power density, indicating localized transfer of stored elastic energy to the disturbance flow. Analyses of cross-slot variants with rounded corners and with a centered cylinder further reveal that neither sharp corners nor a free central stagnation point is the essential destabilizing ingredient; rather, the instability originates from elastic-energy release in extension-dominated regions characteristic of cross-slot flow.
Read the full abstract ▾
Soft Condensed Matter
Perspective: Highly stable vapor-deposited glasses
M.D. Ediger
This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a
liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the ideal glass. Connections between vapor-deposited glasses,
liquid-cooled glasses, and deeply supercooled
liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Binary Black Hole Coalescence and the Dynamics of Scalar Hair in Einstein-Maxwell-Scalar Theory
Jean Pierre Díaz, P. A. González, Eleftherios Papantonopoulos et al. (+1 more)
We investigate the head-on coalescence of charged binary black holes in Einstein-Maxwell-Scalar (EMS) theory using numerical relativity. The binaries are built from charged puncture initial data representing two Reissner-Nordström black holes immersed in a purely kinetic scalar perturbation: the scalar field initially vanishes, while its conjugate momentum provides a small seed for the instability. We evolve the coupled gravitational, electromagnetic, and scalar sectors and monitor the apparent horizons, the emitted radiation, and the scalar field on the horizons. Our simulations show that the nonminimal electromagnetic-scalar coupling can dynamically trigger the growth of scalar hair even when the individual black holes are initially scalar-free. The subsequent
evolution depends on the coupling parameter $\alpha_0$ and on the charge-to-mass ratio of the remnant. For weak coupling, or when charge cancellation suppresses the electromagnetic source after the merger, the scalar field is radiated away or absorbed by the final horizon, and the system dynamically descalarizes. For sufficiently strong coupling and nonzero remnant charge, the scalar field remains finite, and the final black hole approaches a scalarized configuration. For binaries with equal charge-to-mass ratios, $q_1=q_2=0.1$, our simulations identify a transition region between $1900<\alpha_0<2000$, that separates descalarized and scalarized remnants. The coalescence also excites scalar radiation whose time profile is qualitatively correlated with the dominant gravitational-wave mode during the nonlinear stage of the collision. These results provide a binary realization of scalarization/descalarization transitions in EMS theory and show that the fate of scalar hair is controlled by the interplay between the scalar coupling and the charge content of the remnant.
Read the full abstract ▾
All authors Jean Pierre Díaz, P. A. González, Eleftherios Papantonopoulos, Yerko Vásquez
Nuclear Theory
A short-range effective theory for single-neutron halo nuclei with a deformed core
Live-Palm Kubushishi and Daniel R. Phillips
We establish a short-range effective theory for deformed s-wave
halos. The theory applies to a system in which
neutrons are weakly bound to a core
nucleus, and that core
nucleus also exhibits a low-lying rotational band with a $0^+$ ground state and a first $2_1^+$ excited state. The effective theory then must have both
halo degrees of freedom and degrees of freedom associated with rotation of the core. This leads to the particle plus rotor model of Bohr and Mottelson at leading order. We identify the relevant leading-order operators in the
Hamiltonian that respect the
symmetries of the system and the small parameters which define the effective theory's power counting. We carry out calculations for the $^{11}$Be and $^{17}$C systems in which we compute the low-lying positive-parity states of the core $+$
neutron systems up to the core$(2_1^+)$-
neutron threshold. We do this for several different regulator parameters and establish that these energies can be renormalized using the leading-order set of operators. The spectrum is accurately described at leading order in both cases. Decay widths to d-wave core-
neutron states have sizable cutoff dependence, but the Asymptotic Normalization Coefficients (ANCs) in $s$-wave channels exhibit regulator dependence of a size consistent with next-to-leading-order effects. We also compute Coulomb breakup observables and compare with experimental data, finding leading-order results in reasonable agreement with data for both ${}^{11}$Be and ${}^{17}$C. The addition of one next-to-leading-order operator renders the ANCs of all s-wave states stable with respect to the regulator. It consequently also removes most of the 30% variation of the leading-order Coulomb dissociation cross section with the regulator.
Read the full abstract ▾
Optics
Mirror-Symmetry-Enforced Photonic Altermagnet
Chong Cao, Xiong-Xiong Xue, Yee Sin Ang et al. (+1 more)
Altermagnets host momentum-dependent
spin splitting without net magnetization, a
symmetry-enforced band phenomenon whose photonic analogues have so far been realized only in square
lattices governed by fourfold rotation. Here we introduce a photonic altermagnet on a hexagonal
lattice whose helicity splitting is governed by mirror rather than rotational
symmetry. Elliptical
chiral elements of alternating handedness, placed at the vertices of a regular hexagon, leave the two opposite-chirality sublattices connected only by chirality reversal combined with a mirror reflection. Full-wave simulations reveal mirror-related splitting of the two opposite-helicity branches in the band structure and isofrequency contours, with the channels exchanged when the ellipse orientation is reversed. Using a finite photonic
crystal slab, we show that such splitting separates a linearly polarized beam into handedness-resolved channels, thus enabling beam splitting and direction-selective helicity filtering with target-helicity output fractions above 0.85 and output paths continuously tunable through the ellipse rotation angle. These results extend photonic altermagnetism to a previously unexplored
lattice-
symmetry class and establish mirror-symmetric
chiral textures as building blocks for altermagnetism-inspired on-chip
chiral photonics.
Read the full abstract ▾
All authors Chong Cao, Xiong-Xiong Xue, Yee Sin Ang, Haiyu Meng
Instrumentation and Methods for Astrophysics
Development of TIFUUN: Terahertz Integral Field Units with Universal Nanotechnology
Akira Endo, Tom J. L. C. Bakx, Jochem J. A. Baselmans et al. (+50 more)
TIFUUN (THz Integral Field Units with Universal Nanotechnology) is an ultra-wideband mm-submm wave imaging spectrometer that capitalizes on the highly scalable integrated superconducting spectrometer technology. TIFUUN has two slots for integral field units (IFUs), which can jointly be optimized as open-hardware for each astronomical observation in terms of spatial and spectral coverage. These IFUs can have observation frequencies in the range of 90–360 GHz, with spectral resolution up to $R\equiv F/\Delta F \le 1,000$, with up to $\sim$18,000 kinetic inductance detectors (shared by the two IFUs with a flexible ratio). The ultra-wide 4:1 (2 octave) bandwidth optics fits in a remarkably compact volume, by means of thin silicon lenses and a high chief ray angle design. The first pair of IFUs are being developed for the SUBLIME (Study of the Universe By Line Intensity Mapping Experiments) experiment that aims to map CII emission at
redshift $\sim$6 to trace the
cosmic large-scale structure and the buildup of
galaxies during reionization, using TIFUUN on the ASTE 10-m
telescope. The scalability, flexibility and compactness makes TIFUUN a highly compatible and portable system suited also for upcoming
telescope facilities in the vicinity, such as FYST and AtLAST/LST.
Read the full abstract ▾
All authors Akira Endo, Tom J. L. C. Bakx, Jochem J. A. Baselmans, Dries Boleij, Stefanie A. Brackenhoff, Bernhard R. Brandl, Martino Calvo, Shahab O. Dabironezare, Hans van der Does, Rei Enokiya, Sho Fujisawa, Shinji Fujita, Enrico Garaldi, Wouter Gregoor, Masato Hagimoto, Davit Hakobyan, Angelina Harke-Hosemann, Robert Huiting, Shiro Ikeda, Reinier M. J. Janssen, Kenichi Karatsu, Nick de Keijzer, Kotaro Kohno, Takumi Kojima, Alkistis Kyriakidou, Louis H. Marting, Tomotake Matsumura, Cory Meijneke, Tetsuhiro Minamidani, Arend Moerman, Alessandro Monfardini, Kana Moriwaki, Kanako Narita, Yuri Nishimura, Erika Ogata, Leon G. G. Olde Scholtenhuis, Tristan Oude Essink, Jim R. Piek, Matus Rybak, Kana Sakaguri, Seiichi Sakamoto, Aurora Simionescu, Nikita A. Soshnin, Tatsuya Takekoshi, Yoichi Tamura, Akio Taniguchi, David J. Thoen, Sten Vollebregt, Lingyu Wang, Paul P. van der Werf, Stephen J. C. Yates, Naoki Yoshida, Silvia Zhang
Optics
Phase Stable Integrated Delay Line Asymmetric Mach Zehnder Interferometers Enabled by High Efficiency 3 dB Couplers for Chip Scale QKD
Mahsa. Ghezelbash and Abdollah Eslami Majd
Precise temporal delay generation is a key requirement for asymmetric Mach-Zehnder interferometers (aMZIs) used in high-speed
quantum key distribution (QKD) receivers. In this work, a compact integrated aMZI architecture based on a silicon nitride on silicon dioxide (Si3N4/SiO2) photonic platform is presented. A 3-dB directional coupler enabling accurate 50:50 power splitting at the 1550 nm telecommunication wavelength is designed and optimized. The coupling length is initially estimated from the effective index difference between the even and odd supermodes and subsequently refined using three-dimensional eigenmode expansion (EME) simulations. The optimized structure employs single-mode Si3N4 waveguides with a cross section of 1 um x 0.4 um, providing a group index close to 2 and enabling accurate delay engineering. Spectral analysis demonstrates stable 3-dB power splitting across the C-band with insertion loss below 0.5 dB and negligible power imbalance, indicating high transmission efficiency and structural
symmetry. An integrated Si3N4 aMZI delay line providing a 500 ps optical delay, corresponding to a 2 GHz free spectral range (FSR), is further demonstrated. Simulations show nearly constant group delay across the 190-200 THz frequency range with sub-10 ps variation and a smooth, near-linear phase response. These characteristics enable interference visibility above 0.99, corresponding to an estimated
quantum bit error rate (QBER) below 0.5 percent for gigahertz-rate time-bin QKD systems. The wideband linear phase behavior also indicates compatibility with wavelength division multiplexed (WDM) QKD architectures. The results confirm that the proposed Si3N4 integrated aMZI provides a low-loss, dispersion-controlled, and spectrally stable delay solution suitable for scalable chip-scale
quantum photonic receivers.
Read the full abstract ▾
Fluid Dynamics
Turbulence Physics Governs a Scaling Law for the Machine-Learning Predictability Ceiling in Chaotic Flow
Jiashun Guan, Haoyang Hu, Yunxiao Ren et al. (+2 more)
For centuries, the intrinsic chaos of unsteady fluid motion has stood as a formidable barrier to long-term
forecasting. While machine learning (ML) has recently emerged as a transformative paradigm for predicting flow
evolution, it encounters a pervasive yet unexplained "performance wall": an inevitable deterioration in accuracy as the forecast horizon extends. Here, we demonstrate that this deterioration is not a deficiency of model architecture, no matter how state-of-the-art, but a fundamental constraint imposed by the underlying system, which can be understood through
turbulence theory established decades ago. In the setting of bluff body flow, a canonical phenomenon for spatiotemporal complexity in fluid mechanics, we reveal a scaling law governing the deterioration of ML predictability, derived from a Kolmogorov-inspired framework and validated through high-fidelity simulations. Our findings establish a closed loop between the predictability ceiling and its interpretation, bridging the gap between transparent physical theories and modern black-box inference. More broadly, this work provides a theoretical compass for constructing trustworthy ML in complex dynamical systems across the physical sciences.
Read the full abstract ▾
All authors Jiashun Guan, Haoyang Hu, Yunxiao Ren, Michael S. Triantafyllou, Dixia Fan
High Energy Physics (Theory)
Near-horizon modifications in finite $N$ holography
Rishkrith Bairy, Mrityunjay Nath and Debajyoti Sarkar
If one extends the AdS/CFT extrapolate dictionary to large but finite $N$, we are expected to obtain non-perturbative violations of bulk micro-causality. Previously this was achieved by implementing a late boundary time cut-off, while smearing the boundary operator via the HKLL kernel. By performing explicit bulk reconstructions in the backgrounds of near-horizon modified AdS$_2$ and BTZ black holes, we recover the same non-locality estimates as above. For these black hole mimickers, the near-horizon modification is controlled by a throat parameter which sets the scale of this non-locality. In three bulk dimensions, probe dynamics also exhibits a dip-ramp-plateau structure in their spectral form factor when averaged over the throat parameter. Such structure has also been found recently in the background with a stretched horizon or a brick wall.
Read the full abstract ▾
Earth and Planetary Astrophysics
Environmental interactions in Class II systems and their impact on the disk-planet architecture
Pedro P. Poblete, Nicolás Cuello, Tim D. Pearce et al. (+4 more)
Protoplanetary disks evolve in clustered environments where interactions with nearby
stars and interstellar gas are common. Such environmental processes, including
stellar flybys and gas infall, can significantly perturb disk structures over the disk lifetime and potentially influence the
evolution of embedded
planets. We investigate how environmental interactions affect the architecture of Class II systems that host both a disk and already-formed
planets, and assess their impact on disk structure and dynamics, as well as planetary
evolution. We performed 3D simulations using the Phantom SPH code, including multiple
dust species treated with a
dust-as-particles approach that accounts for
dust back-reaction on the gas. We modeled a disk hosting two
planets in a 2:1 mean-motion resonance and subjected the system to two types of perturbations: an infalling gaseous cloudlet and a
stellar flyby. Infall and flyby perturbations change the disk morphology and dynamical state. Infalling gas increases the disk mass and angular momentum, dynamically exciting the
dust and producing eccentric, multi-ring
dust structures. The
stellar flyby truncates the disk, compacting the
dust distribution radially and enhancing episodic radial migration of
dust grains. These processes excite eccentricity in both gas and
dust, leading to distinct
accretion pathways for the
planets. In particular, the flyby promotes inward
dust migration, which may enhance solid
accretion onto the
planets, while infall preferentially increases the
accretion rate of the inner
planet. Environmental interactions during the Class II phase can reshape disk-
planet systems, imprinting dynamical signatures that may persist into later evolutionary stages. Both late infall and
stellar flybys influence the growth and composition of
planets; in particular, infall events can lead to the formation of eccentric, narrow debris disks.
Read the full abstract ▾
All authors Pedro P. Poblete, Nicolás Cuello, Tim D. Pearce, Antoine Alaguero, Josh Calcino, Daniel J. Price, Michael Kuffmeier
Physics and Society
Exploratory Modelling of Multi-System Transformation Pathways from Real-World Data: A SINDy-Inspired Sparse Orthogonal Regression Technique
Sabin Roman, Vitaliy Soloviy and Klaus Kubeczko
Sustainability transitions unfold through interacting dynamics across social, technological, economic, environmental, and governance dimensions. However, many modelling approaches either isolate subsystems or rely on optimisation-based pathways that do not explicitly represent feedbacks, path dependence, and institutional constraints. This study develops a Sparse Orthogonal Regression Technique (SORT), a data-driven dynamical-systems framework for reconstructing multi-system transformation dynamics from harmonised European indicators. Inspired by Sparse Identification of Nonlinear Dynamical Systems (SINDy), SORT infers parsimonious cross-domain dependencies from observed data rather than specifying a full structural model ex ante. The prototype covers energy, emissions, innovation, digitalisation, resource productivity, environmental stress, policy, finance, wellbeing, and resilience. The compact dynamical system is interpreted as a structural representation of medium-term interactions, not as a
forecasting tool. It reproduces differentiated empirical patterns, including steady renewable expansion, nonlinear scaling in transition finance,
diffusion-like digitalisation, oscillatory environmental stress, and sustained reduction in ETS-regulated emissions. Forward simulations diverge from simple linear extrapolation where reinforcing feedbacks are present, illustrating the conditional nature of accelerated decarbonisation. By translating inferred dependencies into a feedback structure, the analysis identifies reinforcing decarbonisation sequences alongside balancing ecological constraints. The model contributes to sustainability transitions research by providing an empirically grounded representation of multi-system feedback dynamics that bridges quantitative modelling and transition theory. SORT offers a compact technique for exploratory reconstruction from real-world transition data.
Read the full abstract ▾
Earth and Planetary Astrophysics
Implications of self-consistent H$_2$O ice optical constants on radiative transfer models of disks
Z. L. Smith, M. K. McClure, I. Kamp et al. (+1 more)
Interstellar water (H$_2$O) ice exhibits significantly varied profiles over its spectral features with temperature and thermal history. No previous radiative transfer model of a protoplanetary disk has fully accounted for these effects over 3 - 200$\mu$m simultaneously. A radiative transfer model with region-based distribution of ices and applicable ice optical constant composites (OCCs) is required to properly model the distribution and spectral signatures of water ice in disks. We build such H$_2$O ice OCCs by combining multiple experiment measurements of the imaginary refractive indices, $k$, to cover from 0.1 - 10,000$\mu$m and perform Kramers-Kronig (KK) integrations to derive updated real refractive indices, $n$. We construct H$_2$O ice OCCs for two thermal histories: first, direct deposit and measure at a fixed temperature ices (DT) and deposit and cool down (DC) ices, for five and eight distinct temperatures, respectively. Next, we self-consistently apply these within a radiative transfer model of a protoplanetary disk according to its thermal structure. This produces the first self-consistent RT profiles for the two most commonly used spectroscopic tracers of thermal processing of H$_2$O ice. To assess the impact that appropriate H$_2$O optical constants have on the 3$\mu$m absorption and 45 and 63$\mu$m emission profiles, we run four RADMC-3D radiative transfer models of edge-on class II disk, HH 48 NE. The four models each use different OCCs; the standard single temperature crystalline and amorphous H$_2$O ice OCCs available from OpTool and our own multi-temperature DT set of OCCs and DC only set of OCCs. We find that ices must have been thermally processed at temperatures higher than the local disk temperature in order to produce crystalline spectral profiles at 3, 45 or 63$\mu$m in disks, suggesting local heating events or outward transport to colder regions.
Read the full abstract ▾
All authors Z. L. Smith, M. K. McClure, I. Kamp, S. M. Cazaux
Atomic Physics
Quantitative analysis of resonant ionization by smooth laser pulses: Connection between effective Hamiltonian theory and strong-field dressed continua
Jakob Nicolai Bruhnke and Jan Marcus Dahlström
Resonant photoionization in the intense high-frequency regime can exhibit extremely asymmetric Autler-Townes doublets whose origin remains debated. It has been attributed either to interference between perturbative ionization pathways or to a non-perturbative dressing of the continuum. Here we show that these interpretations arise from a common effective
Hamiltonian framework, in which dressed-state stabilization is governed by the coherent interplay of resonant and nonresonant pathways. We demonstrate that further simplification, using the strong-field approximation, obscures this mechanism. In contrast, our time-dependent essential-state model, where electrons are rigorously coupled to the continuum, achieves excellent agreement with ab initio simulations of the time-dependent Schrödinger equation for helium.
Read the full abstract ▾
High Energy Physics (Theory)
Asymptotically safe quantum gravity and its phenomenology – a review
Astrid Eichhorn
Asymptotically safe
quantum gravity is an approach to
quantum gravity. It is based on the premise that
quantum field theory can describe the
quantum nature of
gravity in our universe. At its core lies
quantum scale
symmetry. This review provides an introduction to the key ideas of the approach and surveys the current status of the field. Over the last years, the field has taken large strides towards an increasingly realistic setting: First, compelling evidence for
quantum scale
symmetry exists in four-dimensional, Euclidean, pure
gravity, establishing the Reuter fixed point robustly. Second, matter fields, including the Standard Model as well as beyond-Standard-Model-candidates, have been studied in depth, with increasingly conclusive evidence for
quantum scale
symmetry. Most recently, the final gap to a realistic description of
quantum gravity is being closed, because Lorentzian spacetime signature can now be accounted for. As a consequence of
quantum scale
symmetry in the ultraviolet, the approach is highly predictive at all scales. This review discusses the physics of asymptotic safety across all scales. Predictive power for particle physics, black holes and cosmology provides a clear pathway to confronting
quantum gravity with current and near-future observations. The review closes by discussing the connection to other approaches to
quantum gravity. It advocates the perspective that such connections between approaches may lead us to an understanding of universal physical features of
quantum gravity.
Read the full abstract ▾
Plasma Physics
Focused Coherent Microwave Scattering for Spatially Resolved Electron Number Density Diagnostics
H. Jenrow, K. Reindersma and A. Shashurin
This work provides an initial demonstration of Focused Coherent Microwave Scattering (F-CMS) diagnostics technique, an extension of the conventional Coherent Microwave Scattering (CMS) technique that enables spatially resolved measurements. The spatial-resolution functionality was achieved using PTFE lenses to focus the probing microwave beam and isolate a distinct probing volume. The feasibility of F-CMS was demonstrated using glow-discharge
plasma volume with an electron number density of approximately 5x10$^9$ cm$^{-3}$ as a test object. A clear F-CMS output signal was successfully detected upon the discharge initiation. These findings establish a foundation for the further development of the F-CMS technique, which has the potential to enable highly sensitive, spatiotemporally resolved measurements of electron number density in real time, without the need for signal accumulation (sensitivity down to an electron number density of approximately 10$^8$ cm$^{-3}$ is expected). Such capability will be useful for a variety of applications including diagnostics of unsteady flowfields such as those occurring in hypersonic shock tunnels and spacecraft electric propulsion systems.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Wave-optics imprints of dark matter subhalos on strongly lensed gravitational waves. II. Saddle images and detectability
Shin'ichiro Ando
Wave-optics interference in strongly lensed gravitational waves is a new interferometric probe of dark matter substructure: a subhalo population threading a
galaxy-scale lens imprints frequency-dependent distortions on the amplification factor of each macro image. In a companion paper (arXiv:2603.04267), we computed these imprints for the magnified minimum image. Here, we extend the calculation to the saddle-point image and we assess the detectability of the combined signal with the
Laser Interferometer Space
Antenna (LISA). Evaluating the amplification factor at a saddle is numerically delicate, because the equal-arrival-time contours are open and the subhalo signal is a small difference of large terms; we present a time-domain method that resolves it. Across a Monte Carlo ensemble of cold dark matter subhalo realizations, subhalos induce percent-level amplitude and phase modulations in both image parities, while the mean (de)magnification splits by parity: the minimum is net magnified and the saddle net demagnified. Demodulating the macro-image interference recovers the per-image modulations, and a matched-filter analysis that projects out the lens parameters yields a combined detection above $5\sigma$ in $62\%$ of realizations for fiducial massive-black-hole-binary sources of total mass $\sim10^{6}\,M_\odot$ at
redshift $1.5$, provided the source lies close to the lens caustic at small impact parameter $y_{\rm src}\lesssim0.1$. Folding these naive per-event significances through optimistic strong-
lensing rate forecasts yields $10$-$20$ substructure detections over the LISA mission. Strongly lensed gravitational waves are thus a sensitive, complementary probe of substructure at $10^{4}$-$10^{7}\,M_\odot$ scales inaccessible to electromagnetic observations.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Are Cosmological Data Excluding Sterile Neutrinos or Only the Fully Thermalized Limit?
Artur Ladeira, Rafael C. Nunes, Eleonora Di Valentino et al. (+1 more)
We present a cosmological reassessment of light sterile-
neutrino scenarios, examining whether current observations exclude sterile
neutrinos as a class or primarily constrain the fully thermalized case. We consider three distinct realizations: (i) a fully thermalized sterile species (FTS), (ii) a different-temperature sterile-
neutrino thermal relic (DTS) relative to the active
neutrino background and (iii) a Dodelson–Widrow-like (DW) sterile
neutrino with reduced phase-space normalization. Constraints are derived within both $\Lambda$CDM and the CPL dynamical dark-energy framework using combinations of Planck-CMB data, DESI DR2 BAO measurements, and the PantheonPlus and Union3 Type Ia
supernova samples. For baseline data combinations without a local $H_0$ prior, the FTS scenario is strongly disfavored in both cosmological models. Adding the local $H_0^{\rm DN}$ prior allows $\Lambda$CDM+FTS to accommodate the high local $H_0$ value and become statistically competitive with standard $\Lambda$CDM once SNIa data are included, although the sterile-
neutrino mass remains consistent with zero. By contrast, partially populated sterile-
neutrino scenarios remain viable: the DW realization is broadly compatible with current observations, while the DTS scenario yields the least cosmological pressure among the cases considered. Overall, cosmological data mainly require a strongly suppressed effective sterile abundance, leading to tight constraints on \textbf{$m_s^{\rm eff}$} while allowing substantially weaker bounds on the physical sterile mass. We conclude that current observations do not generically exclude sterile
neutrinos, but rather place strong pressure on fully thermalized or highly populated scenarios, highlighting the importance of production history and phase-space distribution when interpreting cosmological constraints.
Read the full abstract ▾
All authors Artur Ladeira, Rafael C. Nunes, Eleonora Di Valentino, Stefano Gariazzo
High Energy Physics (Phenomenology)
Heavy-quark pair-production in DIS at NLO QCD matched to a parton shower
Santiago Castro, Clara Del Pio, Adam Kardos et al. (+2 more)
We present theoretical predictions for heavy-
quark pair-production in deep-inelastic scattering (DIS) at next-to-leading order (NLO) in
quantum chromodynamics (QCD), matched to a parton shower in the POWHEG framework. We revisit the NLO heavy-
quark pair-production cross section and implement a consistent matching to parton-shower
evolution, with careful treatment of heavy-
quark mass effects and the avoidance of double counting between fixed-order and parton-shower radiation. In addition, we compare the virtual NLO corrections available in the literature to one-loop amplitudes obtained through massification in the small-mass limit. This provides an independent validation of the virtual contributions. The study is presently restricted to the
gluon-initiated channel, which dominates the kinematic region of interest at the HERA
collider and remains important for the future Electron-Ion
Collider.
Read the full abstract ▾
All authors Santiago Castro, Clara Del Pio, Adam Kardos, Sven-Olaf Moch, Aris Spourdalakis
Superconductivity
Nontrivial Boundary-Mediated Superconducting Transport in a TRSB Topological Iron-Based Superconductor
Wenyao Liu, Gabriel Natale, Camron Farhang et al. (+22 more)
The interplay of superconductivity, band
topology, and spontaneous time-reversal-
symmetry breaking (TRSB) is expected to enable topological superconducting boundary states. FeTe0.55Se0.45 provides a promising single-material platform because it combines superconductivity, nontrivial band
topology, and spontaneous magnetization in the superconducting state. Here we report evidence for a boundary-mediated superconducting transport response in exfoliated Fe(Te,Se) devices. Polar Kerr measurements show that TRSB emerges below TKerr < Tc and coexists with superconductivity across multiple compositions, providing an independent
symmetry-breaking scale for transport. Using crystallographically sharp, continuous edges and side-surface-dominant contacts, we find that topological FeTe0.55Se0.45 exhibits an anomalous conductance plateau absent in topologically trivial FeTe0.40Se0.60 and Fe1.02Te0.55Se0.45 under comparable measurements. This plateau requires uninterrupted sharp edges connecting source and drain, persists over micrometer-scale separations far exceeding the bulk coherence length, shows strongly suppressed thermal broadening, and collapses when the drain is moved to the top surface. Its temperature
evolution follows the TRSB scale: the plateau remains weakly broadened below T*Kerr and disappears near TKerr rather than Tc. These doping-selective, edge-geometry-dependent, TRSB-correlated, and long-range nonlocal signatures establish experimental criteria for identifying boundary-mediated superconducting transport in FeTe0.55Se0.45 and motivate phase-sensitive and theoretical studies of its microscopic origin.
Read the full abstract ▾
All authors Wenyao Liu, Gabriel Natale, Camron Farhang, Michael Geiwitz, Qishuo Tan, Xingyao Guo, Mason Gray, Vincent LambertiJazzmin Victorin, Huairuo Zhang, James L. Hart, Vsevolod Belosevich, Xi Ling, Qiong Ma, Wan Kyu Park, Kenji Watanabe, Takashi Taniguchi, Judy J. Cha, Albert V. Davydov, Kin Chung Fong, Ethan Arnault, Genda Gu, Rui-Xing Zhang, Enrico Rossi, Jing Xia, Kenneth S. Burch
Plasma Physics
Linear Tearing Growth and Onset of Relativistic Magnetic Reconnection in the Presence of Shear Flows and a Guide Field
Sarah Peery and Yi-Hsin Liu
It has been shown in non-relativistic tearing theory that shear flows will slow the linear phase of tearing instability and can delay onset of
magnetic reconnection. We find using kinetic particle-in-
cell simulations that shear flow as well as guide field strength affect the onset time of relativistic
magnetic reconnection. To model this we develop a numerical solver for the growth rate of the relativistic linear tearing instability, including effects of the motional electric field which has not previously been done. We find slowing of growth due to both shear flows and guide field, and at higher flow shear, transition through an intermediate regime to linear Kelvin-Helmholtz instability.
Read the full abstract ▾
Atmospheric and Oceanic Physics
Zonal asymmetries control the response of atmospheric blocking to Arctic warming in an aquaplanet experiment
Michele Filippucci, Stephen Thomson, Neil Lewis et al. (+1 more)
In recent years a weak but robust response of mean midlatitude circulation to Arctic amplification (AA) has emerged from modeling experiments. However, open questions remain about the mechanisms linking such circulation differences to weather extremes in the midlatitudes. In this study we investigate such mechanisms and the importance of zonal asymmetries in shaping the atmospheric blocking response to AA. We perform idealized aquaplanet simulations in two configurations: a zonally symmetric setup and a zonally asymmetric experiment featuring a localized midlatitude storm track. For each configuration, we examine the response to AA by imposing an anomalous surface heating in the polar region. In the zonally symmetric configuration atmospheric blocking increases uniformly with AA from mid to high latitudes. In the asymmetric configuration, the response is more complex; instead of a zonally uniform response, we observe an upstream displacement of the blocking maximum, which sits at the exit of the localized storm track. We interpret these changes through the lens of the Traffic Jam theory by diagnosing the carrying capacity of the midlatitude flow. In both configurations, the zonally averaged increase in blocking is primarily driven by a weakening of the zonal winds, which reduces the Doppler-shifted Rossby wave group velocity and, in turn, decreases the flow carrying capacity. While the reduction in carrying capacity has similar characteristics in the two configurations, in the asymmetric case it leads to an upstream shift of blocking frequency as a direct consequence of the threshold behavior of blocking onset that lies at the core of the Traffic Jam theory. This mechanism, which has received limited
attention so far, highlights the importance of mean circulation characteristics in shaping the blocking response to external forcing such as Arctic warming.
Read the full abstract ▾
All authors Michele Filippucci, Stephen Thomson, Neil Lewis, Simona Bordoni
Quantum Physics
Optimal GHZ-State Distribution in LOSR Quantum Networks via Local Decoding from Information Sets
Leonardo Oleynik, Shehbaz Tariq and Symeon Chatzinotas
Distributing multipartite
entanglement is a prerequisite for scalable
quantum networks. Networks restricted to local operations and shared randomness (LOSR) avoid the
quantum-
memory and latency costs associated with the real-time classical communication required by LOCC-based networks. However, when only bipartite sources are available, LOSR networks cannot prepare useful GHZ states. In earlier work, we conjectured that multipartite sources overcome this limitation and supported this claim with a single numerical example. In this work, we prove the
conjecture for regular and uniform networks of arbitrary size. By identifying the hyperedges of the network with the coordinates of a linear code, we show that whenever the edges incident to each node form an information set, a fixed collection of local
unitaries, namely the local decoders of the code, transforms the source state into an (N)-party GHZ state with fidelity (d^{m-M}), without requiring any classical communication. Here, (m) denotes the number of edges incident to each node and (M) the total number of edges in the network. For the complete ((N-1))-uniform hypergraph (K_N^{(N-1)}), this fidelity reduces to (1/d). We further prove that this value is optimal among all local-
unitary strategies and exceeds the best fidelity achievable using only bipartite sources. For example, in the four-node case, the optimal fidelity is (1/2), compared with the bipartite bound of (1/8). These results demonstrate that multipartite sources, together with shared randomness, can replace real-time classical communication for
entanglement distribution.
Read the full abstract ▾
Strongly Correlated Electrons
Localization pattern of a mobile impurity in the disordered Kitaev chain
A.V. Sadovnikov and A.N. Rubtsov
We study a mobile
impurity coupled to a Kitaev chain with chemical-potential disorder and ask whether the
impurity behavior distinguishes different regimes of the host system. Exact diagonalization calculations for small periodic chains shows that in the deep topological regime the
impurity localizes only partially, with a smooth increase of $\mathrm{IPR}_d$, whereas in the deep trivial regime it undergoes a much sharp transition to nearly single-site localization. For open chains at strong interaction, DMRG shows edge-localized
impurity density near the Kitaev sweet spot. With increasing chemical potential, the
impurity weight spreads into the bulk and eventually becomes almost uniform. We explain the edge preference analytically from the Majorana-dimer structure: a bulk
impurity rearranges two neighboring dimers, while an edge
impurity affects only one. Disorder competes with this clean edge bias and can pin the
impurity in the bulk. Thus, the
impurity is sensitive to the regime of the host system, although we do not find a strict one-to-one correspondence between the
impurity localization pattern and the host
topology. Instead, the disorder-averaged behavior suggests only an indirect correlation between
impurity localization and the underlying phase of the chain.
Read the full abstract ▾
Astrophysics of Galaxies
X-ray emission maps and scaling relations in IllustrisTNG and MillenniumTNG: Differences between cluster and group regimes
Franklin Aldás, Facundo A. Gómez, Volker Springel et al. (+3 more)
X-ray observations are a primary probe of the intracluster medium, widely used to infer
galaxy cluster masses and scaling relations. We present and validate a pipeline to generate X-ray emission maps of
galaxy groups and clusters from large cosmological simulations, and use it to study the origin of deviations from self-similarity across the group-to-cluster transition. We apply this pipeline to the Illustris-TNG300 and MillenniumTNG simulations, constructing \mbox{X-ray} emission maps and spectra based on APEC cooling functions. For simulations that do not explicitly track individual chemical abundances, we introduce a
metallicity-based prescription that accurately reproduces the full spectral emission. We derive the $L_{\mathrm{X}}$–$M_{500}$, $M_{\mathrm{gas}}$–$M_{500}$, and $T$–$M_{500}$ scaling relations over $10^{12.5} \leq M_{500} \leq 10^{15.5}\,\mathrm{M}_\odot$, compare them with observational data, and quantify the hydrostatic
equilibrium and spectroscopic temperature biases through synthetic X-ray analyses. The simulated scaling relations are in good overall agreement with observations and are best described by broken power laws with a pivot at $M_{500}=10^{13.67}\,\mathrm{M}_\odot$. At high masses, the slopes are close to self-similar expectations; at lower masses the relations steepen significantly, reflecting the growing importance of AGN feedback. X-ray hydrostatic masses are systematically underestimated by $15\%$, independently of cluster mass. When spectroscopic effects are included, the bias becomes mass-dependent, ranging from $15\%$ at low masses to $21\%$ at high masses. The recovered X-ray luminosity, measured in the $0.15$–$1\,R_{500}$ aperture, is also mass-dependent: high-mass clusters are underestimated by $18\%$, while low-mass systems show discrepancies of up to $33\%$, driven by single-temperature spectral modelling of the gas outside the core.
Read the full abstract ▾
All authors Franklin Aldás, Facundo A. Gómez, Volker Springel, Rüdiger Pakmor, Alex Saro, Tiago Castro