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Physics

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Tuesday 30 June

Chemical Physics

Conical Intersections Enable Ultrafast Molecular Spin Control in a Chromium Complex

Zihui Liu, Junhua Zhou, Tianrui Chen et al. (+8 more)

Molecular spintronics seeks to control spin states in single molecules for ultrafast switching and efficient information processing. Transition metal complexes are promising candidates for such applications due to their modular ligand fields, diverse spin configurations, and potential for spin-vibronic coupling that facilitates rapid spin dynamics. Chromium(III) complexes, in particular, offer long-lived emissive doublet states and chemical robustness, making them attractive for room-temperature spin control. Here we investigate the spin-state dynamics of tris(2,4-pentanedionato)chromium(III), [Cr(acac)3], a photochemically stable d3 complex with minimal vibrational congestion. Using ultrafast transient grating and two dimensional electronic spectroscopy with ~10 fs resolution, we directly probe vibrational and electronic dynamics associated with the 4T2 -> 2E intersystem crossing (ISC). These measurements reveal coherent vibrational modes implicated in mediating nonadiabatic spin transitions. Complementary theoretical modelling shows that vibronic coupling and spin orbit interactions promote the formation of multiple conical intersections, providing ultrafast channels for spin-flip dynamics. Metal-ligand bending and stretching modes serve as tuning and coupling coordinates, enabling ISC despite weak spin-orbit coupling in 3d transition metal. Our study provides mechanistic insight into spin-vibronic dynamics in Cr(III) complexes and establishes a design framework for achieving ultrafast molecular spin switching, advancing the development of optically addressable spin centres for future spintronic and quantum technologies.
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All authors Zihui Liu, Junhua Zhou, Tianrui Chen, Michael Penny, Sara Mosca, Mengyuan Cui, Vandana Tiwari, R. J. Dwayne Miller, Fulu Zheng, Ajay Jha, Hong-Guang Duan

Soft Condensed Matter

Self-Generated Electric Fields in Polyelectrolyte Gradients Increase Microparticle Transport

Max Huisman, Ali Azadbakht, Patrick B. Warren et al. (+1 more)

There are many situations in nature and industry where small particles are exposed to gradients of charged polymers, such as enzymes in biological gradients of DNA or RNA, virus particles in respiratory droplets, and colloidal particles in stratifying paint layers. Here, we study the phoretic propulsion of charged microparticles in a polyelectrolyte gradient. We theoretically predict the emergence of a macroscopic electric field from charge-separation dynamics in a polyelectrolyte gradient under a continuous diffusive driving force. We confirm the presence of this self-generated electric field experimentally and show that it significantly increases the phoretic velocity of the microparticles. Finally, for high molecular weight polyelectrolytes we observe that propulsion becomes gradient-independent, consistent with diffusiophoretic predictions for asymmetric electrolytes. Our results show that self-generated electric fields in polyelectrolyte gradients can enhance microparticle transport, with potential applicability wherever charged species of different mobility are continuously driven out of equilibrium.
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All authors Max Huisman, Ali Azadbakht, Patrick B. Warren, Daniela J. Kraft

High Energy Physics (Theory)

Exact Planar Black Hole in AdS-Einstein-Scalar Gravity with IR-Emergent Nearly Conformal Fluid

Sangheon Yun

We study an exact static planar hairy black hole of Einstein gravity minimally coupled to a neutral scalar in four dimensions, which arises in a consistent truncation of type IIA supergravity on AdS$_4\times\mathbb{CP}^3$ dual to the ABJM theory. For nonzero hair the asymptotic region is hyperscaling violating rather than AdS, and the dual theory is a three-dimensional QFT deformed in the UV by an effectively marginally relevant operator with logarithmic running, which flows to the ABJM fixed point in the IR. On the gravity side, treating the hair parameter as an independent variable leads to a thermodynamic central charge $C_t$ and a generalized first law, organized by a radial scaling isometry. Holographic renormalization by the Hamilton–Jacobi method gives the one-point functions in closed form and the trace Ward identity. With the source held fixed, black branes exist below a maximal temperature $T_{\max}\simeq0.19\,\Lambda$ in two branches. On the stable branch the plasma approaches the conformal ABJM fluid with corrections of relative order $(T/\Lambda)^3$, which arise from a state-dependent rescaling of the boundary coordinates, while the other branch is governed by hyperscaling violation with $\theta=9$. A scale-invariant multi-trace boundary condition, which fixes the hair parameter instead of the source, selects the same solutions as the thermal states of a second theory, whose energy density is the bulk mass density and whose equilibrium thermodynamics is exactly conformal. Since the source mode is not normalizable, this second theory is established only in equilibrium, and the theory with fixed source is the dual of the solutions.
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Instrumentation and Methods for Astrophysics

Mechanical Studies of an Additional Light Baffle for the LSST Camera

Hannah Mary Margaret Pollek, Gabriele Rodeghiero, John Andrew et al. (+11 more)

Commissioning the NSF-DOE Vera C. Rubin Observatory consisted of engineering operation and on-sky data-taking, initially with the Commissioning Camera followed by the commissioning run of the LSST Camera (LSSTCam). As with other wide-field astronomical projects, the Rubin team anticipated a significant amount of stray light effects which would necessitate investigation and systematic mitigation. This led the Rubin stray light working group to develop tools, including a robust model of the entire observatory in Zemax, to trace the light paths of stray light artifacts back to their sources. This model along with the other efforts of the working group enabled significant improvements in stray light mitigation leading up to the commencement of the Legacy Survey of Space and Time (LSST). One such potential source was identified as a small chamfer on the L3 lens, for which it was hypothesized that a simple baffle added inside of the LSSTCam near the L3 should prove beneficial to the quality of data being collected in the LSST. Initial Zemax models proved this hypothesis to be correct, but it is important to weigh the improvements made versus the effort, risk, and cost especially when considering any hardware modifications to an instrument that is already running and collecting immense amounts of data each night. This paper investigates the impacts of installing an L3 baffle via a collection of mechanically focused studies, where the principal areas of focus are installation feasibility, baffle geometry, materials & coating selection, and potential impacts to the purge system.
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All authors Hannah Mary Margaret Pollek, Gabriele Rodeghiero, John Andrew, Alex Drlica-Wagner, Alessio Taranto, Luca Rosignoli, Aashay Pai, Douglas R. Neill, Travis Lange, Andrew P. Rasmussen, Aaron Roodman, Pierre Antilogus, Alexandre Boucaud, Martin Nordby

High Energy Astrophysical Phenomena

High Frequency Wideband Study of FRB 20240114A with the Allen Telescope Array

Param Joshi, Vishal Gajjar, Joel Earwicker et al. (+14 more)

We present a high-frequency, wideband observing campaign of the hyperactive repeating fast radio burst FRB 20240114A with the Allen Telescope Array. Between 27 January and 29 October 2024, we obtained 1167 hr of on-source observations across 1344 MHz of simultaneous bandwidth covering frequencies from approximately 900 MHz to 7620 MHz. We detected 97 bursts between ~900 MHz and ~5 GHz, including a strong S-band activity episode, while no bursts were detected in the highest-frequency tunings above ~5 GHz despite substantial exposure. This campaign provides one of the very few extended samples of repeating-FRB activity above 3 GHz, a regime that remains sparsely sampled. We find that the burst rate varies strongly with both observing frequency and epoch, confirming that the emission from FRB 20240114A is highly chromatic and band-limited. We measure the spectro-temporal properties of the bursts and their sub-components, confirming that fractional bandwidth remains approximately scale-invariant. Sub-burst durations decrease toward higher frequencies, and the magnitude of the downward drift rate increases with frequency. The cumulative spectral-energy-density distribution above our completeness threshold is well described by a shallow power law, indicating that high-energy bursts contribute substantially to the observed energy output. We also compare our detections with recently proposed long-timescale frequency-modulation models and find that the ATA high-frequency burst storm is not consistent with a strictly phase-coherent modulation inferred from other datasets. Our results demonstrate that incomplete time-frequency coverage can bias interpretations of burst activity and highlight the need for sustained, simultaneous wideband monitoring of hyperactive repeaters.
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All authors Param Joshi, Vishal Gajjar, Joel Earwicker, Sofia Z. Sheikh, Mohammed A. Chamma, Joe Bright, Luigi F. Cruz, Roy H. Davis, David R. DeBoer, R. A. Donnachie, Wael Farah, Phil Karn, Joao Paolo C. M. Oliveira, Karen I. Perez, Alexander W. Pollak, Andrew Siemion, Michael Snodgrass

Materials Science

Proximity-Induced Skyrmion Stabilization at the Cu2OSeO3/Bi2Se3 Interface

Sina Mehboodi, Victor Ukleev, Chen Luo et al. (+7 more)

We investigate proximity-induced magnetic interactions at the interface between the topological insulator Bi2Se3 and the chiral magnetic insulator Cu2OSeO3, with particular focus on the low temperature skyrmion phase. Broadband ferromagnetic resonance spectroscopy reveals enhanced stability of noncollinear spin textures in the Cu2OSeO3/Bi2Se3 heterostructure compared with bare Cu2OSeO3. In addition to an extra resonance mode in the tilted conical phase that is absent in bare Cu2OSeO3, field cycling resolves two counterclockwise skyrmion resonance branches separated by approximately 238 MHz, consistent with the coexistence of a bulk skyrmion lattice and an interfacial skyrmion phase stabilized by proximity-induced exchange coupling and enhanced interfacial Dzyaloshinskii-Moriya interactions. The finite frequency separation indicates that the two skyrmion phases occupy distinct magnetic energy landscapes while retaining similar resonance character. Resonant elastic x-ray scattering measurements further confirm that the interfacial skyrmion phase spans a broader magnetic-field range than the bulk phase, demonstrating enhanced stability and ordering of topological spin textures at the interface. These findings establish interface engineering as a promising route for extending the stability regime of skyrmion and tilted-conical phases in topological-magnetic heterostructures.
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All authors Sina Mehboodi, Victor Ukleev, Chen Luo, Radu-Marius Abrudan, Jie Xiao, Ronny Golnak, Florin Radu, Matthias Kronseder, Christian H. Back, Aisha Aqeel

Materials Science

Giant perpendicular Edelstein polarization in 2D compensated magnets via bichromatic Floquet driving

Mohsen Yarmohammadi, Daegeun Jo, Marco Berritta et al. (+3 more)

While unconventional $p$-wave magnets can generate nonrelativistic Edelstein polarizations, spin-group symmetries strictly forbid these responses in unconventional magnets with higher-order harmonics, such as $d$-wave altermagnets. Here, we demonstrate that combining Rashba spin-orbit coupling with bichromatic Floquet driving activates giant perpendicular Edelstein polarizations (PEPs) across 2D altermagnets and broader classes of unconventional spin-polarized magnets – a feat monochromatic driving cannot achieve. By dynamically breaking two-fold rotational symmetry, the two-frequency drive (including bilinear, bicircular, and circular-linear configurations) induces a stray-field-free in-plane Zeeman-like field that generates orbitally dominated PEPs (0.5–1.5 $\mu_{\rm B}$). This massive response is governed by universal selection rules tied to the system's magnetic parity and the second beam's harmonics. These emergent PEPs provide a powerful mechanism for perpendicular memory writing.
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All authors Mohsen Yarmohammadi, Daegeun Jo, Marco Berritta, Libor Šmejkal, James K. Freericks, Peter M. Oppeneer

Quantum Physics

State-dependent Gaussian gate set using an optical tweezer for trapped ions

Philip Leindecker, Luka Milanovic, Tanja Behrle et al. (+5 more)

We demonstrate a state-dependent Gaussian gate set on the motional modes of trapped $^{40}$Ca$^+$ ions, realized with an optical tweezer. Dynamic control of the tweezer intensity and position enables local displacement, squeezing, phase-space rotation, and beamsplitter operations, constituting a complete gate set. By varying the tweezer position relative to the ion, we show how the strength of each operation is set by the corresponding spatial derivative of the local optical potential. We further demonstrate the inherent dependence of each operation on the ion's internal state and use coherent spin-motion coupling provided by the tweezer to create a motional cat state. Our work establishes optical tweezers as a unified and local resource for continuous-variable quantum control in trapped ion systems.
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All authors Philip Leindecker, Luka Milanovic, Tanja Behrle, Edgar Brucke, Matteo Marinelli, Julian Schmidt, Jonathan Home, Cornelius Hempel

Superconductivity

Anomalous Hall Effect Driven by Chiral Superconductivity

Alex Levchenko and Leonid Levitov

Direct dc-current signatures of unconventional superconductivity remain scarce. Existing probes of unconventional pairing are typically indirect, relying on phase-diagram anomalies, responses to external fields, or optical measurements. Here we propose a zero-field Hall drag effect as a direct transport signature of chiral superconductivity. The effect arises from Coulomb drag between quasiparticles in a chiral superconductor and those in an adjacent time-reversal-symmetric normal layer. We develop a minimal hydrodynamic theory that includes both quasiparticle normal current and condensate supercurrent in the superconducting layer. In an open-circuit superconducting layer, the condensate generates a counterflowing supercurrent that cancels the net layer current, while a finite quasiparticle current remains and mediates the transverse drag response. This results in anomalous Hall voltage signal appearing abruptly when $T$ is lowered below $T_c$, of the sign reflecting the sign of the superconducting order parameter phase winding.
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Instrumentation and Methods for Astrophysics

Determining stress-based bending mode limits for the Vera C. Rubin Observatory M1M3 active mirror system

Malhar Sonaniskar, Douglas Neill, Ellie Hileman et al. (+1 more)

The Vera C. Rubin Observatory Simonyi Survey Telescope's primary-tertiary mirror (M1M3) is an actively supported, 8.4-m cast borosilicate optic controlled by 156 pneumatic actuators. This work presents a rapid stress-estimation methodology based on the root-sum-square (RSS) combination of Finite Element Analysis to derive pre-computed unit bending mode stresses. Since the stress is proportional to strain, and strain is proportional to displacements, we theorized that since the bending mode displacements can be combined RSS, that the peak stresses would also combine by RSS. We validate the RSS-based major principal stress predictions against NASTRAN simulations for representative bending mode combinations, demonstrating agreement within a few percent for peak Principal major stress across the mirror glass substrate. Unit displacement and corresponding unit stress fields for the first 20 natural bending modes of the M1M3 system are generated using NASTRAN. Representative multi-mode corrections including combinations that include astigmatism, coma, and spherical modes of higher order are then analyzed to compare the resulting peak principal stresses with RSS-based predictions. The method enables near instantaneous evaluation of stress margins for active optics corrections, safety-limit checking, and actuator-force optimization during telescope operations. This paper outlines the formulation, implementation workflow, validation results, and practical use cases for integrating RSS-based stress prediction into the Vera C. Rubin Observatory's M1M3 active optics system.
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All authors Malhar Sonaniskar, Douglas Neill, Ellie Hileman, Petr Kubánek

Quantum Physics

Generating uniform quantum state ensembles with continuous measurement

Theodore McKeever, Ahsan Nazir and Harry J. D. Miller

We investigate the generation of uniform quantum state ensembles via continuous measurement. Using the $SU(d)$ Bloch representation, we derive the associated Langevin and Fokker-Planck equations and identify geometric conditions under which homogeneous monitoring causes global convergence to the uniform pure-state ensemble. We then extend the analysis to mixed states, showing that homogeneous purity-dependent decoherence rates generate uniform Hilbert-Schmidt and Bures ensembles of qubit states through an effective nonlinear stochastic evolution. Additionally, we introduce a post-mixing protocol for qubits: target mixed-state ensembles are assembled by classically sampling trajectories generated with different fixed efficiencies (or decoherence rates). This provides an experimentally feasible route to reconstructing Hilbert-Schmidt and Bures-random mixed-state ensembles, demonstrating that continuous monitoring provides both an exact dynamical generator of Haar-random pure states and a practical route to constructing mixed-state ensembles.
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Astrophysics of Galaxies

AGN Feeding & Feedback Over the Galactic Scales

Filippo M. Maccagni, Vincenzo Mainieri, Isabella Prandoni et al. (+8 more)

Active Galactic Nuclei (AGN) are key drivers of galaxy evolution, triggered by cold gas accreting onto a super-massive black hole. However, the processes regulating this gas accretion (feeding) and how AGN alter the interstellar medium to affect star formation (feedback) remain poorly understood. A major observational challenge is the vast range of spatial scales involved: AGN fuelling and jet-ejection occur over the sub-pc scales, while AGN feedback shocks and heats the ISM preventing star formation over the galactic and circum-galactic scales. Moreover, it is unclear how short stochastic AGN episodes are connected with the long timescales of gas accretion and star formation. In this manuscript, we illustrate how SKAO will provide the unprecedented opportunity to solve the observational limitations of AGN feeding and feedback studies by observing hundreds of nearby AGN down to low radio powers ($10^{21}$ W Hz$^{-1}$). Simultaneous SKA-Low and Mid observations of nearby galaxies will trace the thermal emission associated with star formation and AGN feedback and the synchrotron emission of their jets of relativistic plasma. These broad-band radio observations enable the detailed characterisation of the AGN duty-cycle, unravelling the time-scales of the nuclear activities. Reaching in 10 hours neutral atomic hydrogen (HI) column density sensitivities $\sim 10^{19}$ cm$^{-2}$ at arcsecond resolution, SKA AA4 observations will trace the typical low column density of HI gas in AGN inflows and outflows, to understand the impact AGN feedback over the full galaxy and trace fuelling processes from the environment onto the SMBH. Combining SKA with mm, sub-mm and optical Integral Field Spectrographic observations at comparable arcsecond resolution will provide an exhaustive understanding of the link between multi-phase AGN feeding and feedback processes and star formation.
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All authors Filippo M. Maccagni, Vincenzo Mainieri, Isabella Prandoni, Massimo Gaspari, W. J. G. de Blok, Ilaria Ruffa, Stanislav S. Shabala, Dipanjan Mukherjee, Mayur B. Shende, Antonino Marasco, Paolo Serra

Superconductivity

Universal Spectral Mirage Gaps in Superconductors with Time-Reversal-Symmetric Spin-Orbit Coupling

Xusheng Wang, Gaomin Tang and Shuai-Hua Ji

Spectral mirage gaps, regarded as evidence of finite-energy pairing correlations, have so far been mainly studied in superconductors with Ising spin-orbit coupling (SOC). Here, we show that superconductors with any time-reversal-symmetric SOC can generate mirage gaps near the SOC energy scale when the applied magnetic field has a component perpendicular to the SOC texture, whereas the parallel component produces Zeeman-split spectral features near the superconducting gap. We demonstrate this general principle in superconductors with Rashba and Rashba-Ising SOC. These universal field-dependent signatures establish superconducting spectroscopy as a powerful probe of SOC textures and strengths.
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Soft Condensed Matter

Designing topological edge currents in chiral active matter

Yuta Kuroda, Ellen Meyberg, Gaurav Gardi et al. (+2 more)

Achieving robust functionality in active matter driven away from thermal equilibrium is a current theoretical and experimental challenge. Several recent studies have reported edge currents–persistent transport along walls and density inhomogeneities–in chiral active matter. Yet, the microscopic rules that render these edge currents robust with respect to the confinement geometry and defects remain elusive. Here, we introduce a simple particle model of two-dimensional chiral active swimmers that undergo chirality switching and demonstrate that the model exhibits robust edge currents, i.e., when a single particle is confined, edge currents arise regardless of the confinement geometry or the presence of defects. We also investigate the collective behavior of interacting particles in bulk and find that chirality switching induces phase separation accompanied by edge currents along interfaces. This phase separation is distinct from motility-induced phase separation and is qualitatively explained by an effective hydrodynamic theory derived via bottom-up coarse-graining. Furthermore, by analyzing the topological properties of the linearized hydrodynamic equations, we show that the edge currents in our system are genuine topological edge modes. Notably, phase separation induced by chirality switching can be regarded as the coexistence of two topologically distinct domains. Our results provide guidelines for designing robust edge currents in active matter systems.
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All authors Yuta Kuroda, Ellen Meyberg, Gaurav Gardi, Thomas Speck, Saeed Osat

Soft Condensed Matter

Optimal interactions for addressable self-assembly

Tighe McAsey, Sushrut Tadwalkar, Ali Fele-Paranj et al. (+1 more)

Addressable self-assembly asks that each building block assemble into a particular location in a target structure. Although particles may all be distinct, achieving high yield is a challenge because of monomer depletion: more target structures can nucleate than there are building blocks for, so they form partial fragments which cannot complete growth. We ask how to design the interactions between building blocks to achieve the highest yield in a given time. Using reaction equations describing all the intermediate steps of assembly, combined with numerical optimization, we show that the optimal interactions are such that (i) all bonds are either very strong or very weak, and (ii) the strong bonds form a spanning tree of the target structure. We then prove that when interactions form a spanning tree, monomer depletion cannot occur: assembly can always proceed downhill in energy space, with no kinetic traps. This result is a combinatorial property of the underlying interaction graph, and does not depend on the particular model for the kinetics. It suggests a robust design principle: create a network of strong interactions that has no loops, and make all other interactions much weaker. We validate this principle in numerical simulations of larger structures, and we further show that spanning trees that are more compact have typically better yield. Our results suggest a new framework for understanding monomer depletion and addressable self-assembly, which may be applied to DNA nanotechnology and which may give insight into the assembly pathways of certain multiprotein complexes.
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All authors Tighe McAsey, Sushrut Tadwalkar, Ali Fele-Paranj, Miranda Holmes-Cerfon

Quantum Physics

Automatic quantum function parallelization and memory management in Qrisp

Raphael Seidel

Automated optimization of quantum programs has gathered significant attention amidst the recent advances of hardware manufacturers. In this work we introduce a novel data-structure for representing quantum programs called permeability DAG, which captures several useful properties of quantum programs across multiple levels of abstraction. Operating on this representation facilitates a variety of powerful transformations such as automatic parallelization, memory management and synthesis of uncomputation. More potential use-cases are listed in the outlook section. At the core, our representation abstracts away a class of non-trivial commutation relations, which stem from a feature called permeability. Both memory management and parallelization can be made sensitive to execution speed details of each particular quantum gate, implying our compilation methods are not only retargetable between NISQ/FT but even for individual device instances.
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Astrophysics of Galaxies

Distance to Sh2-106 from Gaia DR3 and its embedded radio population: implications for a candidate explosive outflow

Sergio A. Dzib

Sh2-106 has recently been proposed as a candidate explosive molecular outflow (EMO), but the physical interpretation of the region depends critically on its distance. Published estimates span a wide range, leading to large uncertainties in the inferred size, energetics, and evolutionary timescale of the system. Using Gaia DR3 astrometry, we identify a kinematically coherent stellar population associated with Sh2-106 and derive a cluster parallax of $\varpi_{\rm corr}=0.607\pm0.013$\,mas, corresponding to a distance of $1.65\pm0.04$\,kpc. This value is significantly larger than the commonly adopted extinction-break estimate of 1.09\,kpc. At this revised distance, the inferred kinetic energy of the expanding ionized nebula increases by a factor of $\sim6.5$, reaching $E_{\rm exp}\simeq1.3\times10^{48}$\,erg and placing Sh2-106 in the same order-of-magnitude energetic regime as the Orion BN/KL explosive event, although at a substantially older dynamical age ($\sim3500$\,yr). Archived 5.8\,GHz Karl G. Jansky Very Large Array observations reveal ten compact radio sources in the central region, identifying embedded stellar objects that are suitable for future multi-epoch radio astrometry. No unambiguous high-velocity stellar ejecta are detected in Gaia DR3, although S106\,IR shows a modest peculiar transverse velocity of $\sim5$\,km\,s$^{-1}$ relative to the cluster centroid. The Gaia-based cluster distance, therefore, significantly revises the physical scale and energetics of Sh2-106 and provides the observational framework required to test whether the region represents an older analogue of the Orion BN/KL dynamical disintegration or a distinct explosive phenomenon.
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Quantum Physics

BRIDGE: Lazy-Move Compilation for Dual-Species Neutral-Atom Quantum Computers

Chen Huang, Jingbo Wang, Zhemin Zhang et al. (+5 more)

Neutral-atom quantum computers commonly connect distant qubits by transporting atoms, incurring trap-handover errors, heating, and atom loss. We present BRIDGE (Buffer-Relay Interconnect for Data-stable Gate Execution), a hardware–software co-design that connects stationary data atoms through a fixed, second-species buffer network. Short buffer chains mediate remote controlled-Z gates and return to their initial states after each operation. BRIDGE-F combines relay routing with buffer-mediated SWAPs to relocate quantum states without transporting atoms. BRIDGE-H additionally permits data-atom transport when its full modeled cost is offset by higher survival-weighted fidelity. Across 21 circuits, BRIDGE-F exceeds ZAP and Enola in modeled survival-weighted fidelity, with geometric-mean ratios of $2.1\times$ and $38\times$ and medians of $1.3\times$ and $3.7\times$. Modeled execution latency is lower by factors of approximately $500$ and $1{,}350$, respectively, with circuit single-qubit costs excluded and relay/SWAP Hadamards included. On the same fabric, BRIDGE-F matches or exceeds SABRE-based routing on 17 circuits. Rescoring nominal plans with relay-module error equal to direct-CZ error preserves the advantage over ZAP across all 21 circuits, although recompilation can underperform on QFT. These results identify stationary buffer-mediated connectivity as a promising alternative to repeated atom transport under the stated physical assumptions.
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All authors Chen Huang, Jingbo Wang, Zhemin Zhang, Ming Zhong, Zhuo Fu, Zhiding Liang, Yuan Sun, Dong E. Liu

Computational Physics

Navigating committor landscape of biomolecules with a general pairwise interaction model

Jintu Zhang, Zichang Jin, Huifeng Zhao et al. (+5 more)

Sampling rare conformation transitions between metastable states is a central challenge in atomistic simulations. While the committor function serve as an ideal reaction coordinate for driving enhanced sampling, their high-dimensional inputs and complex functional forms limit the efficacy of standard feedforward neural networks in modeling them. Inspired by recent breakthroughs in biomolecular structure prediction, we propose a novel committor learning framework grounded in the AlphaFold 3 paradigm. By integrating a lightweight, differentiable atom-level embedding with a simplified Pairformer architecture, our method inherently captures intricate dynamical features of diverse biosystems without requiring specialized prior knowledge. We demonstrate the superior expressiveness and accuracy of the proposed framework across multiple atomistic processes. For the folding of the chignolin mini-protein, our model reveals the finer-grained structure of its transition state ensemble (TSE) and a detailed bifurcated reaction mechanism. Furthermore, for calixarene host-guest systems, we develop a unified committor model that elucidates how ligand substituents regulate the ratio between distinct binding pathways, offering new perspectives for structure-based drug design.
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All authors Jintu Zhang, Zichang Jin, Huifeng Zhao, Kai Zhu, Bowei Zhao, Xujun Zhang, Peilin Kang, Tingjun Hou

Materials Science

A technical report on the surface-energy and morphology-based screening for electrode/electrolyte interface compatibility in SOFC/ReSOC materials

Guido Violano and Luciano Afferrante

The performance and durability of solid oxide fuel cells and reversible solid oxide cells are strongly affected by the electrode-electrolyte interface, where charge transfer, ionic transport, adhesion, morphology and thermomechanical stability interact. Early-stage compatibility screening is usually based on electrochemical or compositional criteria, whereas surface-related descriptors are rarely included in a unified framework. This work proposes a surface-based methodology to assess the expected compatibility of candidate electrode-electrolyte pairings. Contact-angle measurements with water and glycerol are used to determine total, dispersive and polar surface free energy components through the Owens-Wendt-Rabel-Kaelble method. Confocal topography is used to extract ISO 25178 roughness parameters, including average roughness, peak-to-valley height, valley depth, skewness, kurtosis and surface slope. A compatibility matrix is constructed by combining energetic affinity and morphological suitability, with emphasis on the electrolyte surface, since the electrode is deposited directly onto the electrolyte substrate. The results indicate that the most promising interfaces are not necessarily those with the highest surface free energy, but those combining high adhesion work, low interfacial energy and a substrate morphology suitable for continuous electrode deposition. The proposed approach provides a rational pre-electrochemical screening tool to prioritize electrode-electrolyte combinations for subsequent validation by electrochemical impedance spectroscopy, area specific resistance, electrical contact resistance, microstructural analysis and durability testing. Although it does not replace electrochemical characterization, it offers a physically grounded way to connect surface chemistry, topography and interface formation in solid oxide cell materials.
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Quantum Physics

Correlation-enhanced metrology from scrambling dynamics in a solid-state spin system

Yu-Chen Li, Shengyu Zhang, Ze Wu et al. (+6 more)

Quantum information scrambling, the dispersal of local information into many-body degrees of freedom, provides a powerful mechanism for generating large-scale correlations and entanglement essential for quantum-enhanced metrology. However, experimentally verifying such quantum-enhanced metrology remains a demanding task. Here, we correlate thousands of spins by engineering chaotic scrambling dynamics in a solid-state nuclear spin system. By leveraging the newly developed scramblon theory, we reveal exponential scaling in both the quantum Fisher information and the signal response to a phase shift. The signal response achieves a correlation-enabled enhancement of $33(2)$ dB over uncorrelated spins. After accounting for signal loss due to imperfect time reversal in the readout stage, we obtain a total metrological gain of 18(1) dB with a phase sensitivity of 40(3) ${\mathrm{\mu rad}}$. Our results bridge quantum chaos with practical quantum metrology, establishing reversible scrambling dynamics as a powerful resource for precision measurements.
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All authors Yu-Chen Li, Shengyu Zhang, Ze Wu, Haochuan Yin, Liqiang Zhao, Xiaoxue An, Jiaxi Cui, Dieter Suter, Xinhua Peng

Instrumentation and Methods for Astrophysics

In Situ Measurements of the Reflectances of the LSSTCam Optics and Assessing the Impact of Optical Ghosts

Aashay Pai, Alex Drlica-Wagner, Lee S. Kelvin et al. (+4 more)

Optical ghosts are image artifacts caused by successive reflections of light between optical surfaces such as lenses, filters, and detectors. These artifacts are unavoidable due to the nonzero reflectances of optical elements and are a major source of contamination for low-surface-brightness science. We use optical ray tracing simulations tuned to observations from LSST Commissioning to quantify the impact of optical ghosts on the LSST data. In particular, we find that ~0.57% of the LSSTCam focal plane is impacted by optical ghosts when averaged across all bands. We also use data from the Collimated Beam Projector to measure the reflectances of various optical elements, generally confirming estimates of ~2% from the systems engineering throughput predictions.
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All authors Aashay Pai, Alex Drlica-Wagner, Lee S. Kelvin, Joshua E. Meyers, Elana K. Urbach, Fritz Mueller, Robert H. Lupton

High Energy Physics (Phenomenology)

NNLO QCD predictions for $t\bar{t}W$ production at the LHC

Xiang Chen

The production of a top-antitop quark pair in association with a $W$ boson ($t\bar{t}W$) is one of the heaviest signatures currently explored at the Large Hadron Collider (LHC) and the corresponding rates have been found to be consistently higher than the Standard Model predictions, highlighting the need for more accurate theoretical predictions. In this contribution, I present next-to-next-to-leading order (NNLO) predictions for this process, in which, for the first time, the necessary two-loop amplitudes are explicitly evaluated in the generalised leading-colour limit.
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Instrumentation and Methods for Astrophysics

Early Telescope Throughput Results from the Collimated Beam Projector at the Vera C. Rubin Observatory

Nathan Amouroux, Parker Fagrelius, Thibault Guillemin et al. (+6 more)

The Vera C. Rubin Observatory LSST requires precise photometric calibration to meet its science goals, particularly for cosmological analyses based on Type Ia supernovae. The Collimated Beam Projector (CBP) has been developed to support this effort by projecting monochromatic point sources of known wavelength and flux directly into the telescope aperture, enabling direct in situ measurements of the full system throughput. We present initial results demonstrating the CBP capability to characterize the instrumental response of the Rubin Telescope and to measure the transmission profiles of LSSTCam broadband filters. In particular, the CBP enables spatially resolved mapping of filter bandpass edge shifts across the focal plane, which can vary by several nanometers as a function of the ray angle of incidence. These early results establish the CBP as a powerful photometric calibration tool and lay the groundwork for continuous throughput monitoring throughout LSST operations.
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All authors Nathan Amouroux, Parker Fagrelius, Thibault Guillemin, Fritz Mueller, Jérémy Neveu, Eli Rykoff, Thierry Souverin, Christopher W. Stubbs, Elana Urbach

Nuclear Theory

Nuclear excitation via inelastic scattering of low-energy vortex electrons

Jia-Lin Zhang, Zhi-Wei Lu, Mamutjan Ababekri et al. (+2 more)

Vortex particles carrying orbital angular momenta (OAMs) have found important applications in broad fields. However, the experimental verification of OAM transfer at the nuclear scale remains a great challenge. Here, we put forward a novel method to probe such OAM transfer through nuclear excitation via inelastic scattering of low-energy vortex electrons. We develop a Dirac distorted-wave Born approximation framework that incorporates the incident-electron OAM and a nonperturbative treatment of the Coulomb field, and apply it to $^{229}\mathrm{Th}$. We find that the vortex and non-vortex electrons yield opposite angular distributions, attributed to the OAM-modified selection rule and the Coulomb-induced redistribution of partial-wave strengths, providing an angle-resolved signature. Moreover, the vortex electron exhibits topological protection in the nuclear Coulomb field. Our method offers a route to probing nuclear-scale OAM transfer and deepens our understanding of the topological properties of vortex particles.
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All authors Jia-Lin Zhang, Zhi-Wei Lu, Mamutjan Ababekri, Yuanbin Wu, Jian-Xing Li

Instrumentation and Methods for Astrophysics

Design and Performance of the Carruthers Geocoronal Imager

Martin Sirk, Alex M. Zhang, Thomas J. Immel et al. (+13 more)

The GeoCoronal Imager (GCI) onboard the Carruthers Geocorona Observatory is the primary scientific instrument of the mission. It is designed to measure far ultraviolet light at 121.6 nm (Lyman-alpha) emitted by hydrogen (H) atoms in Earth's exosphere with the sensitivity, accuracy and precision to meet the mission's scientific objectives regarding the nature of terrestrial exospheric structure and dynamics on both global and regional scales. The GCI is comprised of two co-aligned UV imaging systems. The Narrow Field Imager (NFI) acquires nearly continuous images of exospheric Lyman-alpha radiance near and above the Earth's limb at relatively high spatial and temporal resolution, while the Wide Field Imager (WFI) uses relatively higher optical sensitivity and a wider field of view to detect faint Lyman-alpha emission from the exosphere's outermost extent. Both imaging channels feature identical active pixel sensor cameras, gain-intensifiers, and 6-position optical filter wheels. This paper outlines the instrument design requirements, informed by mission science goals, as well as its performance as measured in the vacuum ultraviolet laboratory test and calibration.
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All authors Martin Sirk, Alex M. Zhang, Thomas J. Immel, Jason B. McPhate, William W. Craig, Cathy Chou, Kodi Rider, Edward H. Wishnow, Anna L. Butterworth, Ellen R. Taylor, Lara Waldrop, John T. Clarke, Evan M. Widloski, Pascal Blain, Jérémy Brisbois, Jean-François Vandenrijt

High Energy Physics (Phenomenology)

Particle Cosmology

Venus Keus

Particle cosmology is the branch of science that seeks to understand the birth and evolution of the Universe by applying the principles of particle physics. It brings together the physics of the very small (fundamental particles and forces) with the physics of the very large (the structure and evolution of the cosmos). In many ways, the early Universe acts as a natural laboratory - one far more energetic than any collider we can build - offering unique insights into phenomena that may never be accessible on Earth. Cosmological observations such as the Cosmic Microwave Background, the distribution of galaxies, and the accelerating expansion of the Universe serve as windows into the fundamental laws of nature. At the same time, theoretical developments in particle physics have led to theories, such as inflation, baryogenesis, and Dark Matter, that help explain key features of the cosmos.
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Strongly Correlated Electrons

The exceptional origin of the strange metal and the LFL-HFL transition

Eoin Quinn

We propose an algebraic framework for the strange metal regime of strongly correlated electrons. We show that the exceptional superconformal algebra $D(2,1;\alpha)$ admits two distinct contractions of its conformal sector: one to a pair of canonical fermions, the underlying degrees of freedom of the Landau–Fermi liquid (LFL), and one to the algebra of Hubbard operators, which characterise a distinct metallic regime, the Hubbard–Fermi liquid (HFL). We argue that competition between these two metallic states drives the emergence of the strange metal as a $0+1$D superconformal bath. We analyse the resulting thermodynamics, and at leading order obtain a parameter-free prediction, $4\pi^2\gamma^{-1} =\chi_s^{-1} + \chi_c^{-1}$, relating the Sommerfeld coefficient to the static spin and charge susceptibilities. We further show that the LFL-HFL transition is discontinuous at low temperature, forced by an algebraic constraint on the Hubbard contraction, and map out the resulting phase diagram. We connect the framework to microscopic lattice models and to the phenomenology of correlated insulators.
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Mathematical Physics

Quantum Stokes matrices and quantum Riemann-Hilbert-Birkhoff maps

Xiaomeng Xu

In this paper, we define quantum Stokes matrices of meromorphic linear systems of ordinary differential equations with noncommutative coefficients and a pole of order $p+1$. We prove that these quantum Stokes matrices satisfy natural quantum exchange relations. These relations allow us to interpret the quantum Stokes matrices as an associative algebra homomorphism, which may be viewed as a quantization of the Riemann-Hilbert-Birkhoff map, regarded as a Poisson map, for meromorphic connections.
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Instrumentation and Methods for Astrophysics

The On-Sky Performance of the LSST Camera CCD Array

Sean Patrick MacBride, Aaron Roodman, Stuart Marshall et al. (+88 more)

The focal plane of the LSST Camera contains 189 individual science CCDs, arranged into 21 raft tower modules, along with 4 wavefront and 8 guider CCDs located in 4 additional corner RTMs. Altogether, the LSST Camera CCDs compose the largest focal plane ever constructed. The LSST Camera is the primary instrument of Rubin Observatory, which will begin the Legacy Survey of Space and Time in 2026. In this paper, we describe the on-sky performance of the LSST Camera CCDs, from receipt at NSF/DOE Vera C. Rubin Observatory in May 2024 to on-sky observations during the first year of operations. We discuss the process to establish functionality of several CCDs which were affected by an electrical short and faulty analog-digital converter, optimizations of readout timing in response to changes in the survey strategy, and implementation of enhanced focal plane safety measures through an active clearing mechanism on the CCDs. Finally, we discuss sensor features observed on-sky, and global performance during the first year of operations. The operations to date of the LSST Camera CCDs have demonstrated the capability of performing a wide, fast, and deep optical imaging survey of the entire southern sky at the Rubin Observatory.
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All authors Sean Patrick MacBride, Aaron Roodman, Stuart Marshall, Yousuke Utsumi, Kevin Fanning, John Banovetz, Theo Schutt, Alexander Broughton, Shuang Liang, Andrew P. Rasmussen, Pierre Antilogus, John Gregg Thayer, Homer Neal, Anthony S. Johnson, Pierre Astier, Seth W. Digel, Andrew Bradshaw, Johan Bregeon, James Chiang, Céline Combet, Guillaume Dargaud, Johnny H. Esteves, Marcelle Soares-Santos, Thibault Guillemin, Claire Juramy-Gilles, Craig S. Lage, Myriam Migliore, Daniel Polin, J. Anthony Tyson, Renee Nichols, Steven M. Ritz, Eli S. Rykoff, Adrian Shestakov, Adam Snyder, Max Turri, Duncan Wood, Travis Lange, Martin Nordby, Hannah Mary Margaret Pollek, Shawn Osier, Boyd Bowdish, Diane Hascall, Margaux Lopez, Scott P. Newbry, Juan Carlos Lazarte, Vincent Lee, Michael Silva, Dave Kiehl, Andrew Hau, Tom Nieland, Nico Linton, David Shelley, Yongqiang Qiu, Mark Freytag, Stephen Cisneros, Chris Mendez, Stephen A. Tether, Alan M. Eisner, Dmitry Onoprienko, Owen Saxton, Kevin A. Reil, Vincent J. Riot, Justin Wolfe, Scott E. Winters, Brian J. Bauman, William Wahl, Paul O'Connor, Françoise Virieux, Alexandre Boucaud, Camille Parisel, Éric Aubourg, Eric Lagorio, Pierre Karst, Aurélien Marini, Didier Laporte, Francis Vezzu, Guillaume Daubard, Patrick Breugnon, Tim W. Bond, Eric Charles, Richard Dubois, Steven M. Kahn, Andrés A. Plazas Malagón, Rafe H. Schindler, Joanne Bogart, Hye Yun Park, Aurélien Barrau, Christopher Z. Waters, Merlin Fisher-Levine, Antoine Bernard, Mile Kusulja