Papers

In this work, we present measurements of ponderomotive instabilities in narrow-band, coaxial resonators in open and closed control loop systems. We show an analytical scheme we will use in future studies to examine the dependency of open loop stability on mechanical parameters. Analytical and simulation models are used to predict the onset of the oscillatory instability in half wave resonators with active disturbance rejection control for amplitude and phase stabilization. We demonstrate that for high amplitude controller bandwidths, ponderomotive oscillations can couple with the controller frequency response via higher harmonics and lower the threshold for the oscillatory instability. We reaffirm the superiority of in-phase/quadrature $(I/Q)$ component control in regards to preventing the oscillatory instability, and show how the phase controller can amplify the crosstalk of disturbances in amplitude and phase control. In cases with large disturbances, this effect can lead to instabilities not present in $I/Q$ control.

In this paper, we revisit this concept of the magnetic field at the site of a magnetic dipole using symmetry arguments that are mathematically rigorous yet intuitive enough to be well-suited for upper-level undergraduate courses in electrodynamics and quantum mechanics. Furthermore, we present symmetry-based results that go beyond those discussed in the standard literature, which are directly relevant to fundamental problems in two-dimensional physics.

The cosmic web preserves a record of the physics that shaped the universe in its earliest moments, the period of exponential expansion known as cosmic inflation. However, if inflation involves significant nonlinear interactions, there are no direct theoretical predictions for the resulting cosmic web. We present the first simulation of the entire history of the universe, from deep in the inflationary epoch to the present-day cosmic structure. Applying this to axion-U(1) inflation, we find that early-universe interactions enhance small-scale structure at high redshift, imprinting the matter power spectrum and the mass function of dark matter halos with signatures of a modified primordial curvature power spectrum and non-Gaussianity. These signatures make high-redshift galaxy surveys, 21-cm observations, and line-intensity mapping promising probes of inflationary physics. More broadly, this ab initio approach provides a novel framework for mapping the signatures of nonlinear inflationary dynamics onto observable cosmic structures across cosmic time.

Roadside units (RSUs) supporting connected and autonomous vehicle corridors need compact models to decide when cooperative maneuvers should be rewarded, deferred, or disabled. Raw sensor streams and neural network weight checkpoints are poorly suited to bandwidth-limited, privacy-sensitive roadside learning. This paper presents $\texttt{FedQML-Edge}$, a federated quantum feature-sketching pipeline for traffic-stability gating. Each RSU constructs a traffic-state summary and sends circuit inputs to a quantum computer; Pauli expectations form a nonlinear sketch processed by a logistic classifier. Only classifier updates are shared with an aggregator, whose head supports reward gating. Raw observations, vehicle records, event traces, and quantum sketches remain private. We evaluate the method using NGSIM trajectories, SUMO predictive gating with sensing noise, and IBM Quantum hardware. On NGSIM, the Pauli sketch reduces test log loss by $14.4\%$ relative to the strongest matched classical sketch. On SUMO, it approaches larger MLPs in stable-window recall while using $7-28$ times less communication per round.

Artificial intelligence (AI) is rapidly becoming a defining feature of contemporary labor markets, yet it remains unclear whether its diffusion is producing a common set of competencies across occupations or deepening occupational divisions. We investigate how AI related skill demand is reshaping labor market structure using large scale online vacancy data from ten countries spanning the Global North and Global South. Combining natural language processing, a large language model, and multilevel bipartite network analysis, we map relationships between occupations, required skills, and career stages in the emerging AI economy. We find that AI demand is overwhelmingly concentrated within a narrow technical core, with approximately three quarters to four fifths of AI related vacancies located in STEM occupations across all countries. AI intensive jobs consistently emphasize Python, SQL, machine learning, and data analysis, generating convergence among highly exposed occupations. However, this convergence does not extend across the wider labor market. Instead, AI competencies remain largely confined to technical domains and are most strongly demanded at labor market entry. These findings reveal convergence within an AI exposed core but divergence between that core and the rest of the occupational structure. Rather than democratizing opportunities, AI appears to reinforce occupational stratification, raising barriers to entry and concentrating the benefits of AI adoption among workers and occupations with prior technological advantages.

Open-shell molecules are highly sensitive probes of correlated oxide surfaces because their partially occupied frontier orbitals strongly amplify subtle changes in adsorbate-substrate hybridization. Combining infrared reflection-absorption spectroscopy with hybrid density functional theory including non-collinear magnetism and spin-orbit coupling, we show that inclusion of spin-orbit coupling is essential to reproduce the vibrational spectrum of NO adsorbed on UO$_2$(111) by suppressing an otherwise artificial overhybridization between the NO frontier orbitals and uranium 5f states. While spin-orbit coupling determines the position of the N-O stretching and, dispersion-driven intermolecular interactions account for its asymmetric broadening at monolayer coverage. These results establish open-shell molecules as sensitive probes of spin-orbit-controlled surface electronic structure and identify NO/UO$_2$(111) as a stringent benchmark for electronic-structure methods describing open-shell molecule-surface interactions.

Despite significant progress on quantum low-density parity-check (qLDPC) codes, building qLDPC processors that are high-rate, high-throughput, hardware-friendly, and fast-to-decode remains a challenge. We introduce mitten codes, a family of qLDPC processor codes of encoding rate $20\%$ and check weight $9$, based on non-abelian groups. Their non-abelian structure evades distance bounds constraining abelian counterparts, allowing mitten codes to reach distance $18$ and beyond with just a few hundred data qubits. The logical operators of a mitten code are related by the group action, yielding a modular, low-overhead logical toolkit: full Clifford operations follow from bridging two reusable seed surgery gadgets or from a single fixed extractor. Furthermore, qLDPC processors based on mitten codes support high-rate surgery that executes many logical measurements in parallel, and parallel magic-state injection into all logical qubits at once. Under circuit-level noise, with our fast decoder, the $[\![300,60,14]\!]$ mitten code achieves, without extrapolation, a block logical error rate of ${\sim}10^{-11}$ per round at $0.1\%$ physical error rate (PER), while the $[\![ 975,195,\leq 24 ]\!]$ code reaches ${\sim}10^{-8}$ at $0.4\%$ PER. Decoding $15$ billion surgery experiments on the $[\![540,108,18]\!]$ code at $0.1\%$ PER, we observe only two logical failures, demonstrating a qLDPC processor capable of running ${\sim}10^{10}$ logical operations. Our decoder is compatible with sub-millisecond average latency per logical cycle, sufficient for real-time decoding on neutral atom hardware. Discovered by an end-to-end design pipeline built on sQetch, a distance estimator orders of magnitude faster than existing tools, and mapping efficiently onto near-term neutral atom and superconducting hardware, mitten codes open a practical path toward fault-tolerant quantum computation.

In this paper, we extend the Comisso-Asenjo magnetic reconnection (MR) mechanism to rotating black holes (BHs) in pure Lovelock/Gauss-Bonnet (GB) gravity in dimension $2N+2\leq D\leq 4N+1$ (where $N$ is the Lovelock polynomial degree of $N$th order term in the action). We perform a comprehensive analysis of the efficiency and power of extracted energy by exploring the effects of the spin parameter, plasma magnetization, magnetic field orientation, and reconnection location. Our results reveal distinctive energetic features of pure Lovelock BHs relative to their Einstein counterparts, except in the special case of $D=3N+1$, where the two theories coincide. Our results demonstrate that magnetic reconnection becomes increasingly efficient in extracting rotational energy from rapidly rotating pure Lovelock BHs with single rotation configuration as the spacetime dimension increases from $D=6$ to $9$. Furthermore, the Comisso-Asenjo MR mechanism can produce higher extraction power than the Blandford-Znajek (BZ) process in certain regions of parameter space because of its enhanced energy extraction rate. These results show that magnetic reconnection is an efficient mechanism for extracting rotational energy from rapidly rotating pure Lovelock/GB BHs, highlighting their relevance to high-energy astrophysical phenomena.

Vanadium Dioxide (VO2) and Vanadium Sesquioxide (V2O3) are Mott insulators that undergo an Insulator-to-Metal Transition (IMT) at ~340K and ~160K, respectively, manifested as an orders-of-magnitude reduction in their electrical resistance. These transitions provide the physical basis for their Volatile Resistive Switching (VRS) behavior, making them promising candidates for threshold-switching devices. Here, we show that the volatile switching in these materials can be strongly affected by non-volatile processes associated with the creation and annihilation of the conducting filament. These processes give rise to pronounced memory effects in which the initial switching voltage substantially exceeds that of subsequent cycles. We identify two distinct mechanisms underlying this behavior in different thermal regimes. In the phase-coexistence regime, a memory effect is observed in V2O3, arising from the spatial redistribution of metallic and insulating domains. Well below the hysteresis regime, an additional electroforming-like memory effect is observed in both VO2 and V2O3 which is attributed to the formation and/or migration of defects under the influence of a high electric field and a current surge associated with the IMT-driven switching. Using a protective internal resistor and a multi-step writing protocol, this normally destructive process can be harnessed to tune the switching voltage and power over a wide temperature range. These results demonstrate a route toward controlled programming of switching parameters in IMT-based resistive switching devices.

The model primarily concerns structural glasses described by systems of topological defects. We explore the scope of this approach and investigate equilibrium behavior within the mean-field approximation. Our analysis reveals three possible equilibrium scenarios, only one of which exhibits a strong glass-forming ability. These scenarios allow for the phenomenological selection of model parameters based on equilibrium behavior, which can then be used to study dynamics during quenching. We identify an upper temperature limit beyond which quenching into the glassy state becomes impossible.

Standard Quantum Optimal Control (QOC) protocols typically maximize a physical objective just at a final target time. However, tracking or measuring the quantum state during the time evolution requires the control at intermediate stages of their evolution. In this work, we extend QOC to accommodate the simultaneous optimization of observables at arbitrary intermediate times. Using a variational approach, we show that intermediate observations induce discontinuities in the costate trajectory, which can be handled with a Krotov algorithm leading to monotonic optimization and convergent results in the limit of zero temporal measurement windows. We apply this multi-time formulation to a Heisenberg XXX spin chain to control the propagation, including field-free revivals, of a Dicke state excitation. Our results demonstrate that simultaneous optimization of the same observable reshapes the driving field to balance intermediate targets with final populations. Finally, we show how this framework enables dynamic tracking of spin excitations and the active manipulation of post-pulse quantum state revivals.

Recent experiments demonstrate the modification of chemical dynamics via cavity-enhanced vibrational energy transport. Here, we provide a microscopic account of both photonic and mode-selective energy transport using direct mesoscale on-the-fly simulations and provide the mechanistic principles of cavity-modified transport under vibrational strong coupling. We find that molecular anharmonicity plays a crucial role in dictating photonic transport, and driving-dependent photonic localization occurs when coupling cavity modes to a highly anharmonic mode of the molecular system. We demonstrate this in cavity-coupled water by tuning the photon frequency (at normal incidence) close to either the harmonic (or weakly anharmonic) bending mode or the anharmonic stretching modes of water. We confirm our understanding using a simple model system by reproducing the photonic transport and its localization. We also demonstrate that the diffusion of mode-selective temperature, quantified via the variance of the H-O-H bond angle or of the O-H bond length, is highly dependent on the cavity photon frequency. We show that the cavity photon frequency can be used as a tuning knob to achieve and control mode-selective energy transport. We also provide a simple analytical understanding of this phenomenon. Our results highlight the rich dynamical interplay of molecular and photonic degrees of freedom that persist in real atomistic systems.

A two species random field Ising model with non-reciprocal interactions between the species is studied using the greedy Glauber dynamics. By solving the dynamics exactly on a complete graph, we obtain the phase diagram of the model as a function of the non-reciprocal interaction ($K$) and the variance ($\sigma$) of the quenched random field distribution. The model exhibits a rich phase diagram with the presence of a chaotic time-oscillatory phase for intermediate values of $K$ and $\sigma$. The chaotic phase has stable time oscillations along with the autocorrelation time that diverges with system size on a complete graph and also in three dimensions. We find that the random field disorder along with non-reciprocal interaction alone can produce a time crystal without an external driving. In two dimensions the autocorrelation time does not increase with the system size and the time crystal phase is absent.

Generative machine learning is increasingly used for inorganic crystal structure generation. Most models and the corresponding evaluation approaches rely on simple forms of crystal structure representation. In this paper, we showcase the power of atom-averaged features from pretrained Machine-Learning Interatomic Potentials (MLIPs), such as MACE, for such tasks. We first introduce a distance measure that assesses the output of material generative models by capturing both quality and novelty in a single distribution-based evaluation framework. In particular, we introduce the Coarse-Fine Transport Distance (CFTD) using two different featurizers, where the quality component is based on coarse MACE features. We showcase CFTD's versatility in capturing crystal-structure quality while also detecting memorization, and compare it with the recently introduced continuous SUN metrics. We further show that coarse MACE features can be used as guidance for a material generative model.

We present local bandpower diagnostics that test whether a candidate dipolar modulation in E-mode polarization data originates in the cosmic microwave background (CMB) itself rather than in noise or systematics. The target is the hemispherical power asymmetry (HPA), one of the most persistent large-scale anomalies in the CMB temperature field; polarization offers an independent probe of its origin, but at Planck sensitivity the polarized sky is noise-dominated. Local power is estimated in overlapping patches on the masked sky, with E-to-B leakage corrected through standard pseudo-$C_\ell$ deconvolution, and dipole directions are fitted independently to the two Planck half-mission maps, which share the same sky but carry independent noise. Tight directional agreement indicates a CMB-level signal, although it cannot distinguish a real modulation from a chance CMB fluctuation. Applied to Planck PR3 Commander data at $\ell = 15$-$40$, the half-mission directions are separated by $8.7^\circ$, a closer agreement than in any of the 300 isotropic simulations ($p < 0.33\%$), and lie near the temperature HPA axis. The coherence appears only in EE, vanishes without leakage correction, and is corroborated by a cross-spectrum check. LiteBIRD, with substantially higher polarization sensitivity, is a natural next application.

Averaging techniques in solar wind measurements have been a longstanding subject of debate. Using Parker Solar Probe (PSP) observations from encounters 1 to 19, we investigate how averaging timescales influence the characterization of turbulent properties across the Alfvenic transition. We compute the rolling mean Alfven Mach number over various averaging intervals, which are then analyzed against switchbacks, magnetic fluctuation energy, and correlation time. We find that the distribution of subAlfvenic intervals is relatively insensitive to judiciously-chosen averaging scales. In contrast, magnetic fluctuation energies increase systematically with larger averaging window, while maintaining a consistent profile across the Alfven transition. We further show that the effective magnetic correlation time decreases with decreasing heliocentric distance and MA, reaching values of several minutes approaching MA =1. These results demonstrate the importance of choosing physically meaningful backgrounds for turbulence parameters, such as the correlation scales, and their impacts on characterizing the solar wind.

The second law of thermodynamics still lacks a general proof applicable to classical and quantum systems across broad ranges of degrees of nonequilibrium, particle interactions, and time scales. In this paper, we show that from Boltzmann's assumption of equal a priori probabilities, the second law naturally emerges via the phase-space continuity equation for the macrostate-level probability $f$ defined over fixed $\Omega$-intervals, where $\Omega$ is the number of microstates. Further analysis suggests a more general assumption underlying the second law: $f$ increases monotonically with $\Omega$, i.e., $\partial f/\partial \Omega > 0$. Based on these findings, the second law can be readily derived for fully chaotic systems. The derivation does not rely on dynamical details, highlighting the statistical nature of entropy increase. For the dilute hard-sphere gas model considered in the H-theorem, the second law may also be established through a simplified approach that requires the Boltzmann equation but does not use the H-function. In contrast, if the positive correlation between $f$ and $\Omega$ breaks down, i.e., $\partial f/\partial \Omega \leq 0$ (e.g., because of local nonchaoticity), the second law of thermodynamics may not apply: entropy can decrease spontaneously with no energetic penalty, and the system can reach an intrinsic-nonequilibrium steady state.

LHC measurements now reconstruct all fifteen parameters of the $t\bar t$ two-qubit spin density matrix, which amounts to a full quantum tomography of the pair. We show that this data constrains CP violation in the top-Yukawa coupling. The coupling enters the density matrix at one loop and produces spin correlations that are odd under CP and do not affect the cross section. Using the first complete renormalized one-loop density matrix and the experimental covariance, we obtain complementary constraints comparable to those from direct tree-level $t\bar t H$ and $tH$ production.

The global phase-space organization of non-linear Hamiltonian systems is traditionally visualized using Poincaré sections. However, rigid choices of sectioning hyperplanes often introduce geometric distortions and coordinate artifacts that obscure or clip fundamental invariant structures. Here, we present a multi-mapping analysis of the planar elastic pendulum to systematically overcome these visual and structural limitations. We implement a comparative framework utilizing inverted phase-space mappings that resolve the dense packing of invariant curves near chaotic boundaries, uncovering an apparent separatrix trajectory hidden in standard views. Leveraging the system's vertical symmetry axis, we derive two novel classes of customized canonical transformations that align the sectioning condition with the underlying force field and invariant trajectories, respectively. We demonstrate that the force-line section balances phase-space density representation near equilibrium and exposes a curvature-driven, hexagon-like boundary deformation. Concurrently, the trajectory-aligned section unrolls highly curved invariant manifolds into a regular grid. When combined with inverted mapping, this trajectory-based approach acts as a structural coordinate zoom, minimizing local metric distortions and shifting delicate, higher-order satellite islands directly into the focal center. Our results demonstrate that relying on a single slice is insufficient to capture complex non-linear dynamics; instead, utilizing at least two orthogonal, field-conforming sections provides a superior, distortion-free diagnostic tool for characterizing structural stability, resonance chains, and global transport barriers in multi-degree-of-freedom systems.

We study a secluded dark-matter scenario in which the smallness of laboratory signals is linked to the origin of neutrino masses. In the four-dimensional theory, the dark sector contains a hidden scalar, a fermionic dark-matter particle, and heavy Majorana neutrinos. The same heavy-neutrino sector that generates light neutrino masses via the seesaw mechanism also induces the Higgs-dark-scalar portal at one loop. This portal is tied to the small observed neutrino masses, naturally leading to very small Higgs-singlet mixing and suppressed signals in direct-detection and collider experiments. We then provide a geometric origin for the boundary condition of the tree level portal coupling being zero $\kappa(\Lambda_{\rm UV})=0$ via a five-dimensional sequestered setup. In this construction, the Standard Model fields and the hidden sector are localized on different branes, with sterile neutrinos propagating in the bulk. Five-dimensional locality forbids a fundamental local tree-level Higgs-dark-scalar contact interaction, while heavy-neutrino loops induce a small residual portal coupling. The main phenomenological parameter controlling the viability of the model is the heavy-neutrino mass scale: direct detection bounds it from above, while Big Bang nucleosynthesis bounds it from below through the requirement that the hidden scalar decays sufficiently early. Depending on the amount of five-dimensional sequestering, the viable region can span heavy-neutrino masses from the multi-TeV scale to the PeV scale, or even higher.

We propose and analyze the structure of a family of bosonic quantum many-body states that have the following features: (i) they include all pure Gaussian states and finite-dimensional matrix-product states as subclasses; (ii) their expectation values can be efficiently computed, allowing them to be used, among other things, for variational calculations; (iii) they admit exact parent Hamiltonians expressed as simple functions of the bosonic creation and annihilation operators.

Two-step thermochemical water splitting driven by concentrated solar heat is a scalable route to renewable hydrogen, but it requires oxides whose oxygen-vacancy formation energies balance facile reduction with favorable reoxidation. Perovskite solid solutions can tune this balance, but the relationship between bulk stoichiometry and local defect energetics remains poorly understood. Here we map oxygen-vacancy formation energetics across Ca-Ce-Ti-Mn (CCTM) perovskites by combining first-principles calculations with a coverage-constrained special quasirandom structure approach that realizes all fifteen symmetry-distinct oxygen nearest-neighbor environments, an interpretable crystal-feature model whose fitted coefficients directly encode the underlying Born-Haber thermochemistry, and a fine-tuned defect graph neural network. Local B-site chemistry dominates the oxygen-vacancy formation energy $E_\mathrm{v}$: varying the nearest-neighbor Mn fraction shifts $E_\mathrm{v}$ by 1.0-1.5 eV depending on local Ce content, whereas A-site Ce variation contributes a smaller, Mn-dependent shift of 0.2-0.6 eV. Short-range B-site cation order, if it can be established and kinetically retained through processing, is therefore a candidate means of tuning redox performance without changing bulk composition. Composition-space maps identify a Ce/Mn-balanced region ($X_\mathrm{Ce}$ = 0.29-0.33, $X_\mathrm{Mn}$ = 0.58-0.67) combining a high fraction of vacancy sites within the targeted $E_\mathrm{v}$ window with phase stability and solubility, whose predicted redox cycle capacity matches or exceeds the ceria benchmark at 1350 $^\circ$C rather than the roughly 1600 $^\circ$C ceria requires. Measurements on three CCTM compositions show cycle capacity increasing monotonically with Ce content under protocols close to the model conditions. The design rules are expected to transfer to related perovskite families.

Large momentum transfer (LMT) enhances the gravitational phase of a light-pulse atom interferometer by a factor $n$, while mirrorless operation with momentum-resolved detection can quadruple the phase-carrying quantum Fisher information. These gains compete in practice because the momentum-space fringe period scales as $1/n$, making the fringe signal increasingly vulnerable to finite detector resolution. We analyze this trade-off in a solvable model with instantaneous lossless $n$-photon pulses, a Gaussian source, and Gaussian detection blur, allowing continuous interpolation between Kasevich–Chu and mirrorless geometries. Closed-form expressions for the blurred output distributions and classical Fisher information are obtained, with a fringe-phase averaging approximation whose error is exponentially suppressed and agrees with numerical simulations at the $10^{-8}$ level. We find that mirrorless operation surpasses a conventional interferometer with the same momentum transfer only when $\sigma_p < 0.91\,m/(n k_0 T)$. Fringe-based readout exhibits an optimal momentum transfer $n^* \simeq 0.93\,m/(\sigma_p k_0 T)$ and a resolution-limited sensitivity floor $\Delta g \simeq 4.4\,\sigma_p/(mT\sqrt{N})$, independent of photon momentum. When this criterion is not satisfied, partial mirror asymmetry can recover part of the enhancement, whereas population-based readout remains insensitive to detector blur and ultimately favors the conventional sequence at sufficiently large $n$. Estimates for $^{87}$Rb sensors show that the mirrorless advantage is primarily restricted to short-baseline instruments.

The membrane paradigm represents a black-hole horizon by a fictitious conducting surface. We derive a microscopic electromagnetic membrane from black-hole matrix quantum mechanics. The fuzzy-sphere horizon carries a Berry monopole, placing its fundamental fermionic partons in lowest-Landau-level states with Ohmic and Hall responses. Off-diagonal bifundamental modes connecting the horizon and exterior matrix blocks become tachyonic near the horizon and condense, dynamically coupling the horizon gauge field to the exterior Maxwell field. In the low-frequency regime $\omega R\ll1$, the fixed-parton transport description predicts frequency- and helicity-dependent reflectivity. At larger frequency, real parton excitations require a black-hole $S$-matrix. Ohm's law then fixes the inclusive absorption probability; unitarity bounds the local absorption cross section by the horizon area, with the classical conductivity $1/4\pi$ saturating this maximal-absorption bound.

Cavity materials engineering, aiming to manipulate material properties by coupling to vacuum fluctuations inside a cavity, is a rapidly advancing field. Despite significant progress, most studies to date have focused on specific materials and cavity configurations. Here, through a comprehensive group-theoretical analysis, we establish general symmetry rules for cavity materials engineering with linearly polarized cavity photon modes. By analyzing the symmetry of the Pauli-Fierz Hamiltonian within the long-wavelength approximation, we provide a classification of the symmetry-breaking patterns induced by cavity modes for all crystallographic point groups. The power of this framework is then demonstrated by quantum-electrodynamical density functional theory calculations. In particular, we explain the distinct cavity-induced lifting of band degeneracies in cubic BaTiO$_3$ for different cavity mode configurations, and the cavity-modified infrared and Raman spectra of monolayer MoS$_2$ due to symmetry breaking. Our results highlight the central role of symmetry in cavity materials engineering and provide general guidelines for future studies in this field.

We show that in rotationally invariant spin-$3/2$ systems the orbital Hall effect originates from interband matrix elements of the orbital magnetic moment. The resulting Hall response is governed by the quantum metric, rather than by the Berry curvature, revealing a purely geometric transport mechanism. Conventional intraband contributions associated with the orbital magnetic moment and Berry curvature are shown to vanish identically in degenerate systems. These results identify the quantum metric as the key geometric quantity controlling orbital Hall transport in degenerate multiband systems.

Local non-unitary deformations of topologically ordered wavefunctions can drive transitions into peculiar states that challenge modern perspectives on gapped quantum matter. The strongly deformed toric code offers a curious case, hosting $m$ anyon condensation alongside perimeter-law scaling of Wilson loops charged under an exact 1-form symmetry—properties that typically do not coexist in gapped ground states. Nevertheless, we rigorously construct local gapped parent Hamiltonians for these strongly deformed toric code states. The Hamiltonians we construct are not strictly finite-range, but contain sums of Wilson loop operators whose coefficients decay exponentially in their diameter. If one adopts standard locality bounds used to define gapped phases—which allow for such exponentially decaying terms—our construction shows that these states realize a trivial gapped phase. Within this locality class, we demonstrate that perimeter-law scaling of Wilson loops does not imply a spontaneously broken 1-form symmetry, and from a dual perspective, that long-range ferromagnetic order and perimeter-law disorder parameter correlations can coexist in a 2D gapped ground state. We evade a recent no-go theorem [Sahay et al., arXiv:2503.01977] by relaxing its assumptions in a manner that we quantify as benign in the thermodynamic limit. More broadly, our results highlight that stronger notions of locality are necessary for prohibiting these counterintuitive properties within a gapped phase.

Aims: We present the first results of Fishing for Jellyfish Galaxies, a pilot citizen-science project using Zooniverse to identify galaxies undergoing ram-pressure stripping (RPS). Methods: Volunteers visually inspected colour images of late-type galaxies from the Dark Energy Camera Legacy Survey, from a sample of 49,703 galaxies selected within $4 \times R_{500}$ of clusters and groups, restricted to galaxies brighter than 19th magnitude in the g and r bands, and with a minimum half-light radius of 2 arcseconds, to aid classification. We detail our data processing, including debiasing classifications and optimising vote-fraction thresholds to maximise completeness and purity, calibrated against a ground-truth set of pre-labelled galaxies. Results: Our final catalogue contains 6739 jellyfish candidates (6621 new), 5430 merger candidates, and 29,729 undisturbed galaxies, with 3910 jellyfish exhibiting prominent tail-like morphologies. We find that the fraction of RPS candidates rises from ~10% in galaxy groups to ~20-30% in massive clusters, confirming the findings of previous studies carried out on smaller samples. For the subset of our RPS candidate sample with spectroscopic data, we measure a median clustercentric velocity 53% higher than the general cluster population, consistent with galaxies in early stages of accretion into the cluster. They are also typically late-type blue galaxies with elevated star-formation rates, in agreement with expectations. These results demonstrate that citizen scientists can reliably identify galaxies that undergo environmental processes. We provide the initial release of 37,599 visually classified galaxies as a resource for future studies of galaxy transformation in clusters.

Traversable wormholes are among the most striking hypothetical solutions of general relativity, but every such geometry requires matter that violates the averaged null energy condition (ANEC). A possible candidate for such matter is the Dirac field. Several recent works have claimed traversable wormhole solutions of the classical Einstein-Dirac-Maxwell system, but these works did not properly take into account that single-particle states do not self-interact electromagnetically and that the mode functions of single-particle states are of positive frequency. In this paper, we show that classical, positive-frequency Dirac fields on certain fixed wormhole geometries can violate ANEC, so they are indeed candidates for sourcing traversable wormholes. We then numerically search for static, spherically symmetric, asymptotically flat traversable wormhole geometries sourced by Dirac fields of a definite frequency $\omega>0$, angular momentum quantum number $\ell$, and definite parity. We find "partial-wormhole solutions," describing a regular wormhole throat with correct asymptotics at one end of the wormhole, but we find that these solutions cannot be continued to a second asymptotically flat end. In the case of reflection-symmetric wormholes, we perform an additional search where we do not assume that the Dirac solution has a definite parity. In this case, after an extensive scan of throat-forming asymptotic data, we find that the conditions necessary for a reflection-symmetric wormhole throat cannot be obtained. Taken together, these results strongly support that the Einstein-Dirac system does not admit traversable wormhole solutions when sourced by a physically meaningful Dirac field.

Gaia DR3 opens a new window for the census of Galactic stellar populations in all-sky surveys, specifically for identifying cataclysmic variables (CVs). While the majority of CVs are distributed below the main sequence on the Gaia HR diagram, identifying them among dominant background stellar populations remains a significant challenge. Here, we present the Gaia Emission-line Magnitude (GEM) diagram - a tool designed to isolate CV candidates from background stars located below the main sequence. Using Gaia photometric data and low-resolution BP/RP (XP) spectra, we construct the GEM diagram by plotting the extinction-corrected absolute magnitude ($M_{G0}$) against the pseudo-equivalent width of the H$\alpha$ line ($pgEW_{H\alpha}$), which is computed via a Gaussian line-profile approximation. We find that known CVs and major stellar background populations, including white dwarfs, hot subdwarfs, and white dwarf-main sequence binaries, occupy distinct regions on the GEM diagram, reflecting both their physical properties and the low-resolution nature of the Gaia XP spectra. We define an empirical selection line on the GEM diagram to separate true H$\alpha$-emitting CVs from background contaminants. As a proof of concept, we apply the GEM diagram to a Gaia volume-limited sample within 250 pc ($G<17.5$ mag) distributed below the main sequence, recovering known CVs. Additionally, we identify three new CV candidates whose accreting nature is supported by archival X-ray data and optical variability. Compared to traditional optical color-based selection techniques, the GEM diagram uses Gaia's low-resolution spectra for initial target identification in all-sky surveys. This provides a more reliable framework for the statistical selection of CV candidates prior to ground-based spectroscopic follow-up and can be scaled to future Gaia data releases to map Galactic emission-line star populations.