Strongly Correlated Electrons
True vs false Fermi surfaces in the Pseudogap regime and their transformation with doping and temperature in the Hubbard Model
Y.M. Vilk
Exact diagrammatic
quantum Monte Carlo (DiagMC) results for the nearest-neighbor Hubbard model motivate a closer study of the pseudogap. Using the improved two-particle self-consistent approach (TPSC+), we analyze Energy (EDC) and Momentum Distribution Curves (MDC) simultaneously. We show that Fermi-
liquid terminology breaks down in the pseudogap regime, requiring a distinction between true and false Fermi surfaces and zero-energy quasiparticle (ZEQ) lines. A false Fermi surface has a momentum-space spectral maximum but a frequency-space depression at zero energy, while a false ZEQ line violates the standard quasiparticle condition $\partial \Sigma'(\mathbf{k},\omega)/\partial \omega|_{\omega=0}<0$.The pseudogap is driven by critical thermal
spin fluctuations, which occur in two dimensions because of the Mermin-Wagner
theorem. Commensurate fluctuations first open an antinodal pseudogap, leaving true Fermi arcs. With decreasing temperature, the Fermi surface evolves into hole- and electron-like false Fermi surfaces. Incommensurate fluctuations generate hot spots near the diagonal, where the pseudogap persists to the
quantum critical point (QCP), whereas at $\mathbf{k}_{AN}$ it disappears before the QCP doping. There, the spectrum has two precursor antiferromagnetic (AFM) bands, both in the unoccupied ($\omega>0$) region. We
benchmark TPSC+ against DiagMC results for the Matsubara spectral proxy $-\mathrm{Im}[\mathcal{G}(\mathbf{k},i\pi T)]/\pi$. TPSC+ underestimates pseudogap suppression in the strong-interaction regime, reproducing DiagMC behavior at lower temperatures or doping. This proxy is equivalent to the spectral function with thermal broadening $\eta=\pi T$, which obscures features when $\pi T$ is not the smallest energy scale. Using $A(\mathbf{k},0)$, we find that hole-like Fermi surfaces emerge at any interaction strength at low temperature, even at weak coupling.
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Mathematical Physics · Cross-listed from math.PR
Anomalous scaling limit of a Brownian particle in a log-correlated potential
Scott Armstrong, Ahmed Bou-Rabee and Tuomo Kuusi
We study a Brownian particle in $\mathbb{R}^d$, $d\geq2$, with drift given by the gradient of a log-correlated Gaussian potential. At weak disorder, we prove convergence to a scaling limit whose law is singular with respect to Brownian motion and whose invariant measure is given by Gaussian multiplicative chaos. The proof uses a renormalization group induction: at each scale, the elliptic operator is well approximated by a
Laplacian with effective diffusivity decaying as a power of scale. We compute this exponent exactly in dimension two.
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Quantum Physics
Quantum Co-Design of Inhomogeneous Many-Body Neutrino Fast Flavor Transformation
Zoha Laraib, Sherwood Richers, Alessandro Baroni et al. (+2 more)
Dense-
neutrino flavor
evolution is a
quantum many-body problem whose fully correlated treatment becomes rapidly more expensive with increasing particle number and spatial structure. We develop a QCNO
quantum simulation code that maps a inhomogeneous forward-scattering
neutrino Hamiltonian with advection and finite-range interactions to TEBD2 product-formula
quantum circuits, and connects ideal many-body simulation, backend-aware execution, and fault-tolerant resource estimation within the same physical model. We reproduce the exact many-body
evolution of the suppressed mean-field-like transverse fast flavor instability through $N=30$ and show that even a single open-boundary interaction generates Rënyi
entanglement and non-stabilizer magic, although noisy backends still produce polarization RMSEs of order $0.1$–$0.3$. The restricted active interaction graph of this problem allows us to estimate the
circuit depth and $T$ gate cost through $N=50$ for both NISQ and fault-tolerant approaches. The measured TEBD2 error in our fiducial ideal simulation of order $10^{-3}$ motivates a synthesis tolerance $\varepsilon_{\rm syn}\sim10^{-7}$, corresponding to about $70$ $T$ gates per $R_Z$ rotation. The generated
circuit contains $1.4\times10^4$ $T$ gates per
qubit for open boundaries (twice that for closed boundaries), requiring an application-level logical-$T$ error target of order $10^{-7}$ for early fault-tolerant architectures.
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All authors Zoha Laraib, Sherwood Richers, Alessandro Baroni, Kathleen Hamilton, In-Saeng Suh
Mathematical Physics
Wave packets asymptotics in $\kappa$-minkowski space
Adith A and A. Bhagwat
In this paper, we study the nature of wave packets and their decay behavior in the $\kappa$-Minkowski space. We employ techniques from singularity theory throughout our analysis. Specifically, we use methods from the theory of Lagrangian singularities and caustics to study the
topology of the energy-level
manifold. The Newton polyhedron method from the theory of oscillatory integrals is applied to analyze the decay behavior of wave packets. We find that for a generic
Hamiltonian in the $\kappa$-Minkowski space, the associated wave packets exhibit different decay rates depending on the control parameter of the system. When the control parameter takes values on the cusp, the system exhibits decay of order $t^{-1/4}$; otherwise, it exhibits decay of order $t^{-1/2}$. This distinctive behavior of wave packets in the $\kappa$-Minkowski makes it fundamentally different from commutative spacetime.
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Computational Physics · Cross-listed from cs.AI
Prior or Feedback? What an LLM Uses When Adapting Neural Operators
Julian Chan and Javier Mora Jimenez
Do LLM scientific
agents rely only on their initial task context, or do they adapt their decisions in response to experimental feedback? We study this question in neural operator adaptation, where a large
language model (LLM) selects fine-tuning configurations under a limited trial budget. Across transfers within and between partial differential equation (PDE) families, the LLM achieves lower held-out test nRMSE than random search and
Bayesian optimisation in nearly every matched comparison. Endpoint performance alone cannot distinguish what happens, so we verify each attribution with controlled interventions. Before observing any validation score, the LLM's first configuration already ranks near the top of the corresponding random-search pool, indicating a useful initial bias. A complementary cold-start intervention shows that the selected base learning rate shifts with the PDE description. Once feedback becomes available, reassigning validation scores among evaluated configurations changes the next proposal in every case tested, whereas a value-preserving rewrite produces no comparable aggregate effect. These interventions establish that the LLM's decision-level actions respond to the given task and observed outcomes, showing that it combines a task-dependent prior with sensitivity to experimental feedback.
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Solar and Stellar Astrophysics
Rotation period of the O giant xi Persei: Coexistence of cyclic and periodic variability. A weakly magnetic candidate star
H.F. Henrichs, N.P. Sudnik and A. David-Uraz
OB
stars exhibit line profile variability, often associated with rotation; notably, in their UV wind-sensitive lines where discrete absorption components tend to recur cyclically. We searched for periodicity in spectral regions of the O7.5III(n)((f))
star xi Persei formed very close to the
star. The NIV 1718 A line was identified as the most uncontaminated spectral with a large and homogeneous available
dataset is available: 307 IUE spectra over 12 years and 11 STIS spectra taken 21 years later. We also studied 322 time-resolved HeII 4686 A spectra and MOST, BRITE, and TESS space photometry, covering a time span of 13 years. We also reconsidered X-ray studies with Chandra. A CLEAN analysis and subsequent weighted least-squares fit of the flux in this region resulted in a unique period of 2.040514(20) d, attributed to rotation. The phase of maximum flux in the NIV, SiIV, Ha, and HeII line profiles coincide with the results of X-ray variability studies. This period was also found in the photometric data. Given the coherent periodic behaviour probing the region of the wind nearest the stellar surface, we propose that xi Per has an as-yet undetected weak global surface
magnetic field. The sinusoidal behaviour suggested that only one
magnetic pole is visible, implying an inclination of i approximately 51 deg, and therefore, 39 deg for the
magnetic obliquity. We present a conceptual framework within which weak wind confinement by a global
magnetic field can create a small magnetospheric disc, while allowing for the formation of more classic corotating interaction regions at higher
magnetic latitudes. The periodic variations are then understood to result from the changing projected area of the magnetospheric disc as a function of rotational phase, both along the line of sight and off the stellar limb.
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Astrophysics of Galaxies
JWST CAPERS: Spectroscopic evaluation of very high redshift galaxy candidates
Callum T. Donnan, Mark Dickinson, Lorenzo Napolitano et al. (+21 more)
JWST/NIRCam imaging has enabled efficient selection of a large number of
galaxy candidates at very high
redshifts. Accurate and robust selection is crucial for statistical analyses, such as measurement of the ultraviolet luminosity function (UV LF). A variety of selection methods and criteria have been proposed in the literature. We evaluate the selection methodology of
galaxy candidates at $z\geq8.5$ using 183 candidates with secure spectroscopic
redshifts obtained from the CAPERS JWST/NIRSpec PRISM program. The success of high-$z$ confirmation is strongly correlated with the photometric signal-to-noise ratio (SNR) in the detection filter, the strength of the Lyman-$\alpha$ break, and the $\Delta \chi^2$ between the best-fitting low-
redshift and high-
redshift spectral energy distribution model. However, the most efficient selection method is the use of a UV LF prior on the inferred $p(z)$ of a source, raising the success rate from $\simeq 35\%$ to $\simeq 77\%$ while achieving greater completeness than conservative SNR and $\Delta \chi^2$ cuts. Out of the 183 candidates we spectroscopically confirm 48 sources at $z\geq8.5$ via detections of emission lines and/or the Lyman-$\alpha$ break (particularly important for those with no emission line detection). We report the highest-
redshift source in CAPERS as UDS-111893 at $z_{\mathrm{spec}}=12.98$, with no sources confirmed at $z>13$. This work provides spectroscopic quantification of JWST/NIRCam photometric selection at $z\geq8.5$, and demonstrates the effectiveness of a UV LF prior for high-
redshift photometric selection.
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All authors Callum T. Donnan, Mark Dickinson, Lorenzo Napolitano, Pablo Arrabal Haro, Anthony J. Taylor, Hollis B. Akins, Ryan Begley, Davide Bevacqua, Adam C. Carnall, Marco Castellano, Fergus Cullen, James S. Dunlop, Steven L. Finkelstein, Carter Flayhart, Mauro Giavalisco, Michaela Hirschmann, Ray A. Lucas, Derek J. McLeod, Ross J. McLure, Casey Papovich, Laura Pentericci, Borja Pérez-Díaz, Thomas M. Stanton, L. Y. Aaron Yung
Quantum Physics
Quartic Certificates for Pure-State Tomography with Pauli Measurements
Hengjian Li, Baisong Sun and Bei Zeng
Full Pauli-basis
tomography of an arbitrary $n$-
qubit state uses the expectation values of all nonidentity Pauli observables. For multiqubit systems, prior knowledge that the state is pure allows some of these observables to be omitted while retaining uniqueness. We study two resulting notions of uniqueness: whether every pure state is uniquely determined among pure states (UDP), and whether every pure state is uniquely determined among all states, including mixed states (UDA). We derive quartic uniqueness certificates from the fourth elementary symmetric
polynomial of operators in the real span of the omitted Pauli observables. An exact quartic identity shows that, for $n$-
qubit systems with $n\geq 3$, every pure state is UDA whenever the omitted Pauli observables contain no four distinct operators that commute pairwise and multiply to $\pm I$. For three
qubits, this condition is also necessary for UDP, yielding an exact characterization of both UDP and UDA. We further prove that UDP and UDA coincide for any number of
qubits whenever the omitted Pauli observables commute pairwise. These results provide directly checkable structural criteria for certifying pure-state
tomography from restricted Pauli measurements.
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High Energy Physics (Theory)
Cornering the Heterotic String
Li-Yuan Chiang, Yu-tin Huang and He-Chen Weng
We study tree-level completions of four-dimensional $\mathcal N=4$ Yang–Mills theory coupled to $\mathcal N=4$ supergravity. Six-point factorization and supersymmetry Ward identities, supplemented by a peculiar-parity restriction on scalar contact terms, impose nonlinear relations between the single- and double-trace Wilson coefficients, $a_{k,q}$ and $b_{k,q}$, of the four-gluon amplitude. The simplest relation, $\kappa^2a_{0,0}=0$, excludes the single-trace $F^4$ interaction at nonzero gravitational coupling, despite its compatibility with four-point supersymmetry. On this gravitational branch, five double-trace parameters determine all coefficients through $a_{7,q}$ and $b_{8,q}$, which are reproduced by a common exponential generating form. Both the heterotic string and a family of infinite-
spin-tower (IST) amplitudes realize this structure. Combining these relations with dispersion relations and partial-wave positivity in $SO(N)$ color channels yields a narrow numerical band closely bounded by the heterotic and simplest IST amplitudes. A
spin-dependent mass gap excludes the IST spectrum and further localizes the region near the heterotic trajectory. An analytic unitarity analysis of the simplest IST gives $N\leq48$ and $g^2/(\kappa^2 m^2)\leq4$, matching the upper limits of the heterotic amplitude, where $m$ is the mass of the first massive level. Along the heterotic trajectory, the numerical bounds also sharply constrain the gauge-to-
gravity coupling ratio at $N=48$.
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Instrumentation and Methods for Astrophysics
Data Representation Matters: Optimizing Machine Learning for X-ray Source Classification by Leveraging Spatio-Spectral Information
Maggie Lieu, Ivan Valtchanov, Marguerite Pierre et al. (+4 more)
Distinguishing between faint extended X-ray sources is a fundamental yet challenging task in X-ray surveys. This paper presents a
benchmark comparison of convolutional neural network models for classifying simulated XMM-Newton observations of AGN and
galaxy clusters, focusing on the impact of data representation and interpretability of that data. We evaluate 1D, 2D, 2D+1D, and 3D CNNs trained on distinct data representations derived from simulated XMM-Newton observations of AGN and clusters: 1D (spectral), 2D (imaging) and 3D (event cube) data. We further apply 3D-GradCAM to interpret the learned features and assess the physical basis for the model's decision making to move beyond black-box classification. Our results demonstrate that increased spectral resolution enhances classifier performance using 1D and 2D information provides a strong baseline, the integration of both domains yields significant diagnostic gains. We find that a 3D CNN architecture applied directly to spatio-spectral event cubes provides the most robust performance, with superior consistency across cross-validation folds. Interpretability analysis reveals that the 3D model autonomously learns to distinguish the diffuse thermal emission of the intracluster medium from the localized, non-thermal power-law signatures of AGN. It exploits multi-dimensional correlations that are lost in lower-dimensional projections. While the performance gain over combined 2D and 1D baselines is marginal, the 3D approach demonstrates an ability to perform implicit background characterisation. By operating directly on total
photon counts within event cubes, this method bypasses the need for manual background subtraction and modelling, offering a consistent, streamlined, end-to-end pipeline for automated classification of X-ray sources in large-scale catalogues.
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All authors Maggie Lieu, Ivan Valtchanov, Marguerite Pierre, Esin Gulbahar, Elias Koulouridis, Iván Muñoz Rodríguez, Lucio Chiappetti
Chemical Physics
MERCE: Method-Space Correlation Energy Extrapolation toward High-Rank Coupled Cluster Accuracy
Mateusz Witkowski, Szymon Śmiga, Pavlo O. Dral et al. (+1 more)
Energy extrapolation is a well-established strategy for approaching
quantum-chemical limits without performing prohibitively expensive calculations. Complete basis set extrapolation is widely used, whereas extrapolation across electronic structure methods remains much less developed. Method-Space Effective-Rank Correlation Energy Extrapolation (MERCE) is introduced as an adaptive effective-rank framework for estimating high-rank finite-basis correlation energies from second-order Moller-Plesset perturbation theory (MP2), coupled cluster with single and double excitations (CCSD), and CCSD with perturbative triples [CCSD(T)]. The method assigns adaptive effective ranks to MP2 and CCSD(T) from the local MP2-CCSD-CCSD(T) correlation energy pattern and fits a compact three-point extrapolation form for each system. A hierarchical model-selection protocol balances cross-
dataset transferability, maximum
dataset-level mean absolute error (MAE) ratios, robustness on developmental sets referenced to full configuration interaction (FCI), size-consistency defects, and performance for A24 noncovalent interaction energies. Across the chemically diverse
benchmarks used during model development, the selected MERCE model substantially reduces CCSD(T) errors and frequently improves upon the tested higher-rank coupled cluster baselines. Transferability is further assessed using calculations performed only after the functional form and parameters were frozen. Formal nonadditivity is quantified using artificial noninteracting pairs and the actual A24 and selected S66 component calculations.
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All authors Mateusz Witkowski, Szymon Śmiga, Pavlo O. Dral, Ireneusz Grabowski
Quantum Physics
Residual-Guided Global-Drive Design in Trapped-Ion Quantum Simulators
Yuanjing Zhang and Zewen Zhang
Trapped-ion
quantum simulators are powerful platforms for exploring many-body physics, yet engineering of arbitrary interaction graphs remains a central challenge. To leverage the intrinsic structure of native motional modes and thereby enhance programmability, a residual-guided optimization protocol is introduced for the systematic design of multi-tone global drive spectra. While the achievable interaction fidelity is fundamentally bounded by the available motional modes, this adaptive strategy converges on the theoretical limit using a number of
laser tones that scales nearly linearly with system size. The versatility of this method enables the synthesis of both long-range and traditionally difficult short-range coupling
topologies. Additionally, by incorporating a penalty for residual motional excitation, the
algorithm effectively mitigates errors associated with incomplete closure of phase-space trajectories. Overall, this scalable framework significantly expands the programmable capabilities of trapped-ion architectures while maintaining low computational overhead and high potential for experimental implementation.
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High Energy Physics (Theory)
Stringy resolution of bouncing singularities
Ilija Burić, Ivan Gusev and Andrei Parnachev
We study the near-horizon geometry of near-extremal NS5 branes, which admits an exact worldsheet description in terms of the $SL(2,\mathbb{R})_k/U(1)$ coset. In the supergravity limit, the analytically continued time-domain reflection amplitude exhibits a singularity associated with a null geodesic bouncing off the black-hole singularity, analogous to the bouncing singularities of boundary correlators in asymptotically AdS spacetimes. We show that finite-string-length effects render this amplitude an entire function of complex time, completely resolving the bouncing singularity. This resolution is nonperturbative in the inverse coset level: the singularity persists at every finite order in the expansion.
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Instrumentation and Methods for Astrophysics
Opening the Black Box: What Neural Networks Learn from Pulsar Timing Array Data
James Alvey, Andrea Mitridate, Mauro Pieroni et al. (+1 more)
In recent years, simulation-based inference (SBI) methods have been proposed to address several data-analysis challenges faced by existing and planned gravitational-wave experiments. For example, SBI classification has recently been shown to significantly improve the prospects for detecting anisotropies in
pulsar timing array (PTA) data. In this work, we use a simple toy model of a PTA to provide a more pedagogical explanation of how, and under which circumstances, SBI-based detection can improve on classical detection statistics for gravitational-wave background anisotropies.
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All authors James Alvey, Andrea Mitridate, Mauro Pieroni, Joseph D. Romano
Instrumentation and Detectors
Cavity Characterization for the Princeton Axion Search
Nate Otto, Jianyang Fu, Joelle-Marie Begin et al. (+4 more)
The Princeton
Axion Search (PXS) targets the mass window $0.8\text{--}2.1~\mu\text{eV}$ (corresponding to frequencies $200\text{--}500~\text{MHz}$) at DFSZ sensitivity. The experiment, a haloscope, will use a cylindrical copper-plated aluminum cavity of $700~\text{mm}$ diameter and $1022~\text{mm}$ height, immersed in a $5~\text{T}$ solenoidal
magnetic field. A $152~\text{mm}$ diameter tuning rod spanning the height of the cavity rotates to tune the primary mode resonance from $390\text{--}480~\text{MHz}$, the frequency range for initial operations. We deduce the electric and
magnetic field mode patterns using a combination of dielectric and metallic bead perturbations on the empty cavity. The measured mode frequencies and the $\text{TM}_{010}$ field profile, as a function of tuning rod position, are in excellent agreement with simulations. We describe the effect of fabrication and assembly imperfections, including the bowing of end plates and tilt of the tuning rod. The welded seams and end-cap joints are demonstrated to not significantly degrade $Q$. We combine measurement and simulation to assess an uncertainty on form factor across the full tuning range. Our results validate PXS's cavity architecture and inform future searches for sub-$\mu\text{eV}$
axions, in which large-volume high-$Q$ structures are required to reach QCD sensitivity.
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All authors Nate Otto, Jianyang Fu, Joelle-Marie Begin, Saptarshi Chaudhuri, Roman Kolevatov, Lyman Page, Joe Wiedemann
Materials Science
The Stability of Rutile Oxides for Oxygen Evolution Catalysis: From Mechanistic Understanding to New Descriptors
Katarina Kretschmer, Michael H. Eikerling and Tobias Binninger
Polymer electrolyte water electrolysis is considered as a pivotal technology for green hydrogen production. Iridium dioxide (IrO2) serves as the
benchmark electrocatalyst for the anodic oxygen
evolution reaction (OER) in these
cells. However, the scarcity and cost of iridium drives efforts to find durable and cost-effective replacements or drastically reduce the iridium loading. While ruthenium dioxide (RuO2) offers comparable activity, its practical utility is impacted by its stability being inferior to IrO2. The presented computational study analyzes the metal-oxygen bond strengths in bulk IrO2 and RuO2 to provide insights into the electronic origins of their differing stabilities. Through a comparative analysis of the electronic structure of bulk rutile IrO2, RuO2, and selected MO2 systems, it is able to discriminate the covalent and ionic contributions to the metal-oxygen bond using
crystal-orbital-derived electronic descriptors.
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Strongly Correlated Electrons
Transducing quantum-spin-ice correlations into Weyl Fermi-arc transport at a synthetic Kondo lattice interface
Tsung-Chi Wu, Michael Terilli, Christian Zaprianov et al. (+5 more)
Quantum spin ice hosts collective excitations and
quantum fluctuations that are largely electrically silent because the materials supporting them are insulating. Coupling this
magnetic environment to surface-localized Weyl states offers a route to encode its correlations directly into Fermi-arc transport. Experimental access to this regime, however, has remained largely unexplored. Here, we realize a synthetic Kondo
lattice interface between the Weyl semimetal $\mathrm{Eu_2Ir_2O_7}$ and the
quantum-
spin-ice candidate $\mathrm{Tb_2Ti_2O_7}$, and demonstrate that
quantum-
spin-ice correlations are imprinted on Weyl Fermi-arc transport. At ultra-low temperature, electronic transport evolves from a sixfold anisotropic response at low field into a twelvefold response over an intermediate field window, before entering a reentrant sixfold anisotropy at high field. No analogous twelvefold response occurs at the classical-
spin-ice interface. The
quantum–classical contrast shows that the same itinerant electronic channel acquires qualitatively different
symmetry information when interacting with the
quantum-fluctuating Tb moments, consistent with an interfacial coupling between the Weyl surface states and the transverse, multipolar degrees of freedom, in addition to the longitudinal, dipolar contribution. Our work establishes synthetic Kondo
lattice interfaces as a route for transducing frustrated
quantum magnetism with multipole correlations into distinct Weyl Fermi-arc transport responses.
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All authors Tsung-Chi Wu, Michael Terilli, Christian Zaprianov, Eun Sang Choi, David Graf, Qinghua Zhang, Lin Gu, Mikhail Kareev
High Energy Physics (Phenomenology)
Machine Learning Meets High-Energy Nuclear Physics: From Pattern Recognition to Physics-Integrated Discovery
Xun Chen, Weiyao Ke, Yu-Gang Ma et al. (+2 more)
Machine learning (ML) in high-energy nuclear physics (HENP) is entering a new stage in which physical knowledge is incorporated more directly into data analysis, simulation, and physics inference. This mini-review focuses on developments that have matured in the past several years. Whereas earlier applications emphasized event classification, pattern recognition, and surrogate models for selected observables, recent work has moved toward physics-integrated workflows: calibrated
Bayesian extraction of QCD matter properties, dense-matter equation-of-state inference from heavy-ion and
neutron-
star data, generative event modeling, neural unfolding of weak physical signals, differentiable inverse solvers, gauge-equivariant and
diffusion-based
lattice-field samplers, and neural reconstruction of model functions in holographic QCD. We survey recent applications of ML in heavy-ion collisions,
neutron-
star physics,
lattice QFT, and holographic or continuum QCD. The emphasis is not on ML architectures alone, but on how they enter concrete physics workflows, how physical constraints such as
symmetries, conservation laws, causality, thermodynamic stability, and
topology are imposed, and how uncertainty quantification and validation determine whether an AI-assisted result can support a reliable physics conclusion.
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All authors Xun Chen, Weiyao Ke, Yu-Gang Ma, Long-Gang Pang, Kai Zhou
High Energy Physics (Phenomenology)
Bosonic Contribution to Parity-Violating Møller Scattering at NNLO
Lisong Chen, Jens Erler, Ayres Freitas et al. (+1 more)
We calculate the dominant bosonic two-loop virtual electroweak corrections to parity-violating Møller scattering at low energies. The electron effective weak charge is extracted from the polarization asymmetry, retaining all contributions that are enhanced by $(1-4\sin^2\theta_W)^{-1}$ or $\ln^2(M_{W,Z}^2/Q^2)$ relative to the tree-level contribution. Analytical results are obtained using the expansion by regions method in the low-energy limit $Q^2\ll M_{W,Z}^2$. Within this approximation, the dominant two-loop bosonic corrections shift the electron effective weak charge (or equivalently the polarization asymmetry) by $0.3\%$. We examine the origin of the leading contributions to this result and assess the remaining theoretical uncertainty from purely bosonic contributions for the MOLLER experiment to about 0.1%.
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All authors Lisong Chen, Jens Erler, Ayres Freitas, Juhun Kwak
Mesoscale and Nanoscale Physics
Accessing electronic entanglement via photo-assisted two-electron tomography
M. Paulet, G. Rebora, M. Bienioszek et al. (+4 more)
Witnessing
entanglement between electrons propagating in
quantum circuits requires accessing their two-electron coherences, which encode the two-particle
quantum correlations generated by Coulomb interactions. Yet, experimental reconstruction of two-electron coherence remains a major challenge. We introduce photo-assisted two-electron
tomography, a
quantum coherence reconstruction protocol from dc-currents and time-averaged current correlations, routinely measured in electron
quantum optics experiments. Driving an energy filter with a small rf tone encodes off-diagonal coherences in the frequency domain into the dc-current response, enabling single-electron
tomography without resorting to current-noise measurements. Extending it to two channels, current correlations after two photo-assisted filters reconstruct the two-electron Wigner distribution and isolate its irreducible two-body part. When applied to Coulomb-coupled
quantum Hall edge channels, the protocol reveals interaction-induced energy
entanglement. Signatures of this
entanglement are visible through the violation of an
entanglement witness based on Cauchy-Schwarz inequalities, as well as Wigner function negativities, which remain resolved above the thermal background for realistic device parameters. A generalized Franson geometry further extends the approach to intra-channel two-electron coherences. This opens a direct pathway to detect and characterize electronic
entanglement in ballistic
quantum circuits.
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All authors M. Paulet, G. Rebora, M. Bienioszek, G. Ménard, G. Fève, A. Feller, P. Degiovanni
High Energy Physics (Phenomenology)
Bubble nucleation with thermal higher-dimensional operators
Fabio Bernardo, Maciej Kierkla, Nicholas Leister et al. (+2 more)
We quantify the impact of higher-dimensional operators in the effective theory for bubble nucleation, focusing on supercooled phase transitions in the classically conformal Abelian-
Higgs model. While high-temperature dimensional reduction organizes hard thermal corrections into a tower of operators in a three-dimensional effective field theory, recent results show that dimension-six terms can dominate over higher-loop corrections to the
equilibrium thermodynamics of the strongest transitions. To assess their effect on the nucleation rate and the derived near-
equilibrium phase-transition observables, we develop a perturbative framework that includes them in the full one-loop nucleation rate. Including higher-dimensional operators both in the bounce action and in the fluctuation determinants, we solve the resulting Sturm-Liouville problem without a derivative expansion, using a modified Gel'fand-Yaglom method. For strongly supercooled transitions, we find that higher-dimensional operators only marginally affect the nucleation rate and the resulting observables. As a byproduct, we delineate the regime of validity of the high-temperature nucleation effective theory in supercooled phase transitions.
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All authors Fabio Bernardo, Maciej Kierkla, Nicholas Leister, Philipp Schicho, Pedro Schwaller
Quantum Physics
Theory of the CH$_\text{S}^-$ Defect in MoS$_2$ Confirming the Origin of the Quantum Emission
Chanaprom Cholsuk and Tobias Vogl
Establishing the microscopic origin of localized emission in two-dimensional materials through consistent agreement between experiment and theory remains challenging. Recent STM/STS-STML measurements assigned an emission near 1.8 eV in monolayer MoS$_2$/hBN(2L)/
graphene to the negatively charged CH$_\mathrm{S}^{-}$ defect. However, a comprehensive theoretical description of this emitter is still lacking. Here, we develop such a description and systematically investigate the photophysical properties of CH$_\mathrm{S}^{-}$ in monolayer MoS$_2$, two bilayer configurations, and a MoS$_2$/hBN
heterostructure. The defect retains a similar local geometry and favors a singlet ground state in all four environments, whereas its electronic transition, zero-
phonon line, electron-
phonon coupling, radiative lifetime, and transition-dipole orientation depend strongly on the surrounding layers. The isolated-monolayer model exhibits substantial structural reorganization and produces a broad, dominant
phonon sideband that is inconsistent with experiment. Adding an adjacent layer, either MoS$_2$ or hBN, substantially suppresses the
phonon sideband, with only a minor dependence on the defect position in bilayer MoS$_2$. In particular, the MoS$_2$/hBN model yields a weak
phonon sideband and closely reproduces the experimental photoluminescence lineshape. Our results thus provide the first theoretical agreement of CH$_\mathrm{S}^{-}$ emission and further reveal the role of adjacent layers in determining the electronic, vibronic, and optical properties of the
quantum emitters in two-dimensional materials.
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Materials Science
A Universal Polybromide Melt Strategy for the Direct Conversion of Metals into Optoelectronic-Grade Bromide Perovskites
Arindam Mondal, Mark Baranov, Lonia R. Friedlander et al. (+2 more)
Halide perovskite systems require specific metal oxidation states (M2+ or M+/M3+ pairs), limiting processing flexibility during traditional synthesis and posing stability challenges for multivalent metals like Sn, Cu, and Au. This work anchors a profound paradigm shift: a universal, single-step, organic-solvent free synthetic platform that directly converts stable elemental metal films into bromide perovskite and perovskite-related systems for a wide variety of (opto)electronic applications. The synthetic platform uses methylammonium polybromide melt (PBM) that reacts at room temperature with different elemental metals, including Pb, Sn, Au, and Cu, successfully transforming them into their respective Br-perovskite phases: MAPbBr3, MASnBr3, MA2Au2Br6, and MA2CuBr4. It is shown that the PBMs chemical activity can be tuned, and in situ X-ray diffraction captures in two cases transient intermediate phases during phase
evolution. For Sn, which tends towards overoxidation to Sn4+ phase, changes in the PBMs composition coupled with a metallic Sn mediated comproportionation reaction allowed suppressing overoxidation, and formation of high quality MASnBr3 films under ambient conditions. Overall, oxidation and disproportionation potentials are found to be useful metrics for predicting M:PBM reaction outcomes. Industrially, this approach should be fully compatible with roll-to-roll infrastructure, providing a low-barrier pathway to scale next-generation optoelectronic technologies.
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All authors Arindam Mondal, Mark Baranov, Lonia R. Friedlander, Mariela J. Pavan, Kirill Sobolev Yevgeny Rakita
Earth and Planetary Astrophysics
Longitudinal distribution of Io's dayside atmospheric density
R. S. Giles, J. R. Spencer, T. K. Greathouse et al. (+3 more)
Since 2001, we have used the TEXES high resolution mid-infrared spectrograph at NASA's Infrared
Telescope Facility to study the density of Io's SO$_{2}$-dominated atmosphere. The spectra cover several SO$_{2}$ absorption lines near 530 cm$^{-1}$ and are used to retrieve the equatorial SO$_{2}$ column density. In addition to covering a long time period, our 191 independent observations also cover the full range of Io central longitudes, allowing us to study the longitudinal variability of Io's dayside atmosphere in more depth than has previously been possible. By improving our modeling of longitudinal variability and using a seasonal model to apply a temporal normalization to the retrieved SO$_{2}$ densities, we produce two complete longitudinal distributions of Io's equatorial SO$_{2}$ column abundances, one representing perihelion and one representing aphelion. Both show the same hemispheric asymmetry that has been observed in previous studies, with the highest densities near 200W and the lowest densities near 305W. We find that the contrast between the maximum and minimum densities is a factor of ~27 at aphelion and a factor of ~16 at perihelion. Both longitudinal distributions are asymmetric, with a sharper drop-off on Io's trailing hemisphere than on the leading. We compare these longitudinal distributions to the distributions expected if the spatial variability were primarily driven by volcanic activity, SO$_{2}$-ice inhomogeneity or the effects of eclipses. We conclude that the effect of eclipses is important, but insufficient to explain the shape of the observed longitudinal variability, and frost distribution is likely to also be important.
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All authors R. S. Giles, J. R. Spencer, T. K. Greathouse, C. C. C. Tsang, E. Lellouch, M. A. López-Valverde
Medical Physics
Deep preferential evolution guided by pairwise comparisons enables motion correction in photoacoustic tomography
Karteekeya Sastry, Yousuf Aborahama, Junhao Zhu et al. (+2 more)
Motion artifacts in three-dimensional photoacoustic
tomography (PAT), caused by extended mechanical scanning of sparse arrays, degrade image quality. Since sparse sampling results in low-quality sub-reconstructions, tracking motion directly is challenging. While final image quality could in principle guide artifact correction, conventional regularizers do not accurately reflect photoacoustic image quality. Here, we introduce deep preferential
evolution (DPE), a derivative-free optimization framework where a learned image comparator guides evolutionary search over reconstruction parameters. By learning relative quality differences between same-target image pairs rather than absolute quality scores, the comparator generalized more robustly from simulation to in-vivo images (after unlabeled domain calibration) than an absolute scorer. Comparator-based DPE successfully corrected synthetic motion across diverse anatomies and backgrounds, and it mitigated artifacts from natural, unconstrained motion in human palm images. These results demonstrate that pairwise learned comparison can provide a transferable optimization objective for high-dimensional image restoration when labeled experimental training data are scarce.
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All authors Karteekeya Sastry, Yousuf Aborahama, Junhao Zhu, Manxiu Cui, Lihong V. Wang
Mathematical Physics
Sylvain Carrozza, Johann Chevrier and Luca Lionni
The
entanglement structure of a bipartite pure state is characterized by its
entanglement spectrum, or equivalently, by the family of Rényi-$k$
entanglement entropies with integer $k$. Taking the difference of two such
entropies defines a quantity known as an
entanglement spread, that is monotonous under local operations, and that vanishes if and only if the
entanglement spectrum of the state is flat. We introduce a multipartite generalization of this notion which, for a fixed number $D\geq 3$ of parties, results in a collection of maps indexed by pairs of $D$-edge-colored graphs (obeying some condition). Each member of this collection takes the form of a difference of two multipartite Rényi
entanglement entropies, each associated to a local
unitary polynomial invariant (known in this context as a trace-invariant), and is shown to be monotonous under local operations. We then argue that a previously introduced family of so-called hypergraph-tensor (HT) states can be understood as a multipartite counterpart to the family of flat bipartite states. Indeed, we first prove that, when $D=3$, a tripartite pure state is HT if and only if it minimizes a particular (infinite) family of
entanglement spreads. Second, we embed the set of HT states into the much larger family of spectral hypergraph-tensor (SHT) states, defined by a new Ansatz we introduce. We then prove that HT states can be uniquely characterized as the minimizers of some fixed
entanglement spread among SHT states, for arbitrary $D\geq 3$. We also investigate SHT states in their own right: in particular, we characterize their orbits under local
unitary transformations. Finally, along the way, the asymptotic large-$N$ expectation values of a number of
entanglement spreads are computed in the Haar-random state of local dimension $N$.
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Earth and Planetary Astrophysics
Gen-EBM: an energy balance model for terrestrial planets. Climate multistability from snowball to post-runaway greenhouse climates
Siddharth Bhatnagar, Emeline Bolmont, Maura Brunetti et al. (+6 more)
Climate multistability and tipping points are fundamental properties of planetary climates that depend sensitively on
climate feedbacks. We introduce the Geneva Energy Balance Model (Gen-EBM), a new 1-D latitudinal EBM for rapid exploration of terrestrial
planet climates, and use it to investigate how planetary rotation, eccentricity, and thermal inertia shape
climate attractors and multistability. Gen-EBM is implemented in Rust and builds on previous
exoplanet EBMs by incorporating a temperature-dependent outgoing longwave radiation prescription spanning Earth-like, runaway-onset, and post-runaway greenhouse regimes. We construct bifurcation diagrams from ensembles of simulations and explore the effects of rotation rate, orbital eccentricity under the mean-flux approximation, and surface thermal inertia. Including post-runaway greenhouse states substantially enlarges the parameter space over which multiple
climate states coexist. Within our model framework, slow rotators approach the spatially homogeneous limit and maintain broader temperate stability ranges, whereas fast rotators develop strong equator-to-pole temperature gradients that narrow the temperate branch. Under the mean-flux approximation, increasing eccentricity enhances
climate variability and can alter the attractor structure itself. The critical eccentricity at which temperate climates disappear depends strongly on thermal inertia, with ocean-rich
planets remaining stable to larger eccentricities than land-dominated
planets. Gen-EBM therefore broadens rapid parameter-space exploration to climates spanning temperate, runaway-onset, and post-runaway regimes. Its computational efficiency and flexibility make it a valuable bridge between simple
climate models and 3-D general circulation models.
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All authors Siddharth Bhatnagar, Emeline Bolmont, Maura Brunetti, Jérôme Kasparian, Tim Kallioinen, Marine Leyvraz, Guillaume Chaverot, Yonatan Birhanu Haile, Dóra Takács
Quantum Physics
Experimental generation of asymmetric keys from the parity structure of a two-photon six-qubit entangled state
Sanchari Chakraborti, Soumya Asokan, Sunita Khoth et al. (+2 more)
We propose and experimentally demonstrate an asymmetric key-generation scheme in which public and private keys are derived from a six-
qubit photonic entangled state. A six-
qubit entangled state is generated from two
photons, each carrying one polarization and two path
qubits. The state is prepared in an equal superposition of eight of the sixty-four six-
qubit basis states, in which each
photon's three
qubits form a codeword of the classical [3,2,2] even-parity code, and are distributed between the two parties, Alice and Bob. This ensures, each triple is a uniformly random codeword and the two codewords are locked together through the correlation. The parity constraint is a local stabilizer, so each party verifies it on its own data every round, and eliminates the bit flip errors arising from imperfections, detector dark counts and multiple occupancy before it enters the raw key. A single publicly announced bit, chosen at random from either of the path
qubits, allows each party to reconstruct the other's full triple while leaking no information to third party. We realize the desired six-
qubit state using a Sagnac-based type-II SPDC source, reporting a Bell-CHSH parameter S = 2.798 +/- 0.008, by implementing gate operation on polarization and path degree's of freedom. This approach provides a physics-based alternative to public-key cryptosystems built on computational hardness assumptions. A t-bit string generated from multiple rounds for encryption will be intrinsically random. Without the private key, one needs at least O(2^t) runs on an t-
qubit quantum system to find the matching bit to decrypt.
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All authors Sanchari Chakraborti, Soumya Asokan, Sunita Khoth, Sujai Matta, C. M. Chandrashekar
High Energy Physics (Theory)
Horizon symmetries of exact hydrodynamic actions
Mike Blake, Arpit Das and Richard A. Davison
We demonstrate how horizon
symmetries of AdS black holes are realised in the hydrodynamic actions for the dynamics of the dual stress tensor. A recent approach for obtaining such actions involves a choice of horizon boundary conditions, and we show that diffeomorphisms that preserve these give rise to
symmetries of the corresponding hydrodynamic action. We obtain explicit hydrodynamic actions for small amplitude perturbations of black holes in JT and AdS$_3$
gravity using this approach and demonstrate explicitly the existence of these
symmetries. For a natural choice of boundary conditions, the resulting actions manifestly realise gauge
symmetries previously proposed for effective theories of maximal chaos.
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Cosmology and Nongalactic Astrophysics
An analytical model for non-local stochastic field-level galaxy bias on the sphere
Maximilian von Wietersheim-Kramsta, Nicolas Tessore, Benjamin Joachimi et al. (+3 more)
We present the `Bias of Overdensities in Large-scale Tracers on the Sphere' (BOLTS) model, a novel analytic
galaxy bias model for projected fields on the sphere that incorporates stochasticity and non-locality already at linear order while enforcing physicality and statistical isotropy. Rather than as a deterministic transfer function, we model
galaxy bias as a statistically isotropic random field, allowing stochasticity to enter through fluctuations in the bias itself. The construction yields an explicit decomposition into a linear, non-local
stochastic and deterministic components in harmonic space. We fit the model parameters to the projected power spectra measured in large-volume hydrodynamical simulations (FLAMINGO), enabling sampling of
galaxy populations from simulated matter fields while conditioning on
galaxy properties such as
halo mass or
redshift. By construction, the model reproduces the two-point statistics down to the simulation resolution, and without being calibrated on it, BOLTS recovers the equilateral bispectrum within the sample variance of the simulation down to comoving scales of $\mathcal{O}(10 \, \mathrm{Mpc})$ for
halo masses $ M_{\rm{h}} > 10^{11.5}\,\rm{M}_{\odot} $ over
redshifts $0 < z < 3$. Relative to local bias prescriptions, it more accurately captures amplitude-phase correlations and mode coupling in the measured wavelet phase harmonics wherever the stochasticity of the tracers exceeds their discreteness, including low
redshifts and lower
halo masses $M_{\rm{h}} = 10^{11.5}\,\rm{M}_{\odot}$ where non-linearities become important. This model enables efficient field-level forward modelling for simulation-based inference and model comparison with large
datasets from forthcoming
galaxy surveys including Euclid, Rubin LSST, and Roman, while improving the accuracy of
galaxy bias modelling with respect to standard linear deterministic models.
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All authors Maximilian von Wietersheim-Kramsta, Nicolas Tessore, Benjamin Joachimi, Qianjun Hang, Niall Jeffrey, Joop Schaye