High Energy Physics (Phenomenology)
Forward-backward asymmetry in the $H\to Z\gamma\to\overline{f}{f}\gamma $ decay
A.I. Hernández-Juárez, G. Tavares-Velasco, A. Fernández-Téllez et al. (+1 more)
We study the forward-backward asymmetry in the three-body decay process $H\to Z\gamma\to\overline{f}f\gamma$, induced by complex form factors in the $HZ\gamma$ vertex. To estimate its magnitude, we derive constraints on the real and imaginary parts of the $CP$-violating form factor $h_3^{Z\gamma}$ using current LHC measurements, obtaining upper limits of about $0.9$ GeV. These bounds are of the same order of magnitude as those derived from electric dipole moments (EDM). We find that the asymmetry can reach values of order $10^{-1}$ and may be accessible at the HL-LHC.
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All authors A.I. Hernández-Juárez, G. Tavares-Velasco, A. Fernández-Téllez, D. Watko
Superconductivity
Demonstration of a scalable all-solid-state refrigerator exploiting diffusion geometries and limiting interfacial conductances at temperatures below 1 kelvin
Robert M. Young, Zachary Stegen, John X. Przybysz et al. (+32 more)
Solid-state refrigerators using Normal-metal/
Insulator/
Superconductor (NIS) junctions have previously demonstrated excellent electron cooling but limited ability to cool
phonons. The energy gap of the
superconductor is used as an energy filter to allow higher than average energy electrons to preferentially tunnel from the normal-metal through the
insulator into the
superconductor where they travel as quasi-particles. Typically, the heat is moved and work is done to deposit hot quasi-particles into a normal-metal quasi-particle trap for rejection to the next refrigeration stage. Realizing that (1) the quasi-particles flow diffusively, driven by a concentration gradient in the electric field-free
superconductor, and (2) that the undesirable backwards leaking of heat from the hot-side trap can be reduced by engineering the geometry and materials at the
superconductor-to-trap interface, enhanced cooling can be achieved. Fabrication of the refrigerator was accomplished using a tungsten and titanium-tungsten
alloy as the cold-side normal-metal, aluminum
oxide as the
insulator, aluminum as the
superconductor, and gold as the trap, with the cold-side NIS portion being attached to the hot-side gold trap by bump bonding. The refrigerator consisted of 1121 junction pairs, each pair being an SINIS unit, all electrically connected in series. Using this we have measured the effective
phonon temperature of a 3.9 mm x 3.9 mm x 0.65 mm silicon chip driven down to 70 mK from a bath temperature of 120 mK, and down to 174 mK from a 271 mK rejection temperature (a cooling of -97 mK). This is the first demonstration of the sub 1 K cooling of an entire silicon chip using NIS junctions.
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All authors Robert M. Young, Zachary Stegen, John X. Przybysz, Edward R. Engbrecht, Aaron A. Hathaway, Justin C. Hackley, Kirby B. Myers, Christian C. Thorpe, Aurelius L. Graninger, Robert Miller, Diego A. Morales, Roberto D. Carcamo, Glen Walters, Jeric P. Sarad, Nicholas F. Pleim, Seth Whitsitt, Joshua T. Shipman, Anil Erol, Melissa G. Loving, Evan Donohue, Corey A. Kegerreis, Benjamin Dalfort, Moe S. Khalil, Christopher Pinion, Randi Jaramillo, John Milinichik, Sandro J. Di Giacomo, Thomas Zodda, Nilesh Tralshawala, Gregory R. Boyd, Jonathan M. Cochran, Katherine A. Maddock, Michael P. De Feo, Aaron A.Pesetski, Marc E. Sherwin
Accelerator Physics
Bayesian Optimization of Molybdenum-99 Production by Laser Wakefield Acceleration Using Coupled PIC and Monte Carlo Simulations
Bruno Silveira Nunes, Nilson Dias Vieira Junior, Mirko Salomón Alva Sánchez et al. (+2 more)
This work applies
Bayesian optimization to a loop composed of PIC simulations of
laser electron acceleration and Monte Carlo (MC) simulations of bremsstrahlung-induced
nuclear reactions, to maximize the production of molybdenum-99, the precursor of the most used radiopharmaceutical in
nuclear medicine, metastable technetium-99. PIC and MC simulations are computationally intensive, and besides reducing the time spent, the
Bayesian optimization coupling both simulations resulted in an improvement of an order of magnitude in the $^\text{99}$Mo yield over a previous work, in which the output of an optimization loop based solely on PIC simulations was used a posteriori to estimate $^{99}\mathrm{Mo}$ production through a MC simulation.
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All authors Bruno Silveira Nunes, Nilson Dias Vieira Junior, Mirko Salomón Alva Sánchez, Alexandre Bonatto, Ricardo Elgul Samad
Quantum Physics
Entanglement assisted quantum $(r,\delta)$-locally recoverable codes
Carlos Galindo, Fernando Hernando, Helena Martín-Cruz et al. (+1 more)
Quantum $(r,\delta)$-locally recoverable codes are
quantum error-correcting codes capable of correcting $\delta-1$ qudit erasures within one subset of qudits of cardinality at most $r+\delta-1$. In this paper, we introduce the more general framework of
entanglement-assisted
quantum $(r,\delta)$-locally recoverable codes, assuming that the local recovery operation is assisted by receiver-held qudits that remain unaffected by erasures. We establish necessary and sufficient conditions for these codes to satisfy this property. For codes derived from Hermitian or Euclidean constructions, we establish connections between
entanglement-assisted
quantum and classical notions of $(r,\delta)$-local recoverability, and derive a Singleton-like bound. Furthermore, we construct optimal pure entan\-gle\-ment-assisted
quantum $(r,\delta)$-locally recoverable codes from several families of classical codes, including bivariate $J$-affine variety codes, BCH codes, and homothetic-BCH codes.
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All authors Carlos Galindo, Fernando Hernando, Helena Martín-Cruz, Ryutaroh Matsumoto
Cosmology and Nongalactic Astrophysics
Confirmation of the Finch Flatter-Fainter Relation for the Quadruple Images of Lensed Point Sources
Kaitlyn E. Roman and Paul L. Schechter
Finch et al (2002) derived relations for the summed absolute magnifications of quadruply lensed images that vary inversely with flattening in two alternative isothermal gravitational potential models. However, they did not elaborate on the selection effects this "flatter-fainter” relation induces in actual lensed systems. We test the relation against the Luhtaru et al (2021) sample of 39 quadruply lensed
quasars (38 of which we model successfully), using predicted rather than observed magnifications to avoid the complication of microlensing. We found that the summed predicted magnification decreases by a factor of ten over the observed range of flattening.
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Quantum Physics
Block Encoding Non-Abelian Lattice Gauge Theory
Patrick Draper
Gauge theories like
lattice QCD present a complex problem for
quantum simulation. In a basis where the electric part of the
Hamiltonian is simple, the
magnetic part, generally expressed as a sum over the plaquette operators of the
lattice, is quite complicated, producing correlated transitions between several link and site degrees of freedom. We provide an efficient block encoding of the plaquette operator in the irrep basis, a refinement of the electric basis where the internal gauge-variant degrees of freedom are integrated out. The construction removes the plaquette
matrix element scaling wall which has been a significant barrier for other approaches in this basis. The
algorithm leverages a convenient factorization property of the
matrix elements, cheap classical precomputation, and
quantum oracles built from lookup tables and programmed rotations.
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Quantum Physics
Hardness of approximation for minimum-weight decoding of two-dimensional topological quantum codes
Louay Bazzi and Georges Khater
Efficient decoding is essential for the practical realization of fault-tolerant
quantum computers. We study the computational complexity of minimum-weight decoding for topological
quantum codes. For surface codes under the depolarizing channel, we consider Minimum-Weight decoding, which seeks a minimum-weight Pauli error consistent with both the $X$- and $Z$-syndromes. For color codes under independent $X$- and $Z$-error models, we consider Separate Minimum-Weight decoding. Assuming $P\neq NP$, we establish
polynomial additive inapproximability gaps for these problems. Specifically, for the toric code and the $4.8.8$ color code on the
torus, there exists a constant $c>0$ such that no
polynomial-time
algorithm can always produce a solution whose weight is within $cN^{1/14}$ of the optimum, where $N$ is the number of
qubits, unless $P=NP$. For the planar surface code, we obtain an $\Omega(N^{1/18})$ gap. Our inapproximability results use Håstad's hardness of approximation for MAX-3SAT. Our reduction develops a general, modular framework for
embedding logical constraints into coupled primal–dual join problems on a
lattice. A key ingredient is a localization argument that controls unintended interactions between different parts of the construction.
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High Energy Physics (Phenomenology)
$CP$-odd form factor in the $HWW$ vertex
A.I. Hernández-Juárez, G. Tavares-Velasco and J. Martínez-Ramón
We revisit the $CP$-odd form factor in the $HWW$ vertex within the Standard Model (SM), which is induced only at the one-loop level when one of the $W$
bosons is off-shell. To the best of our knowledge, the numerical evaluation of this form factor is presented for the first time. The relevant contributions from
quark loops are of order $10^{-5}$, well below the current experimental sensitivity. The phenomenological implications are studied through asymmetries in unpolarized and polarized observables in three-body decays.
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Pattern Formation and Solitons
Vector Akhmediev Breathers and State Transitions in the Degenerate and Nondegenerate Regimes for the Coupled Sasa-Satsuma System
Mengyuan Lan, Lei Wang and Yinchuan Zhao
We investigate vector Akhmediev breathers (ABs) in the degenerate and nondegenerate regimes for the coupled Sasa-Satsuma system describing two coupled ultrashort optical pulse envelopes. Based on the carrier-wavenumber relations of the two-component background, we examine three configurations: a single vanishing wavenumber, a pair of opposite wavenumbers, and two nonzero wavenumbers of unequal magnitudes. These configurations admit distinct maximal degrees of nondegeneracy. For each configuration, we derive the reduced spectral equations, construct the existence diagrams, and compare the resulting branches with the modulation-instability gain spectra. Owing to the distinct carrier-wavenumber
symmetries, nondegenerate-type modes can occur in spectrally degenerate regions, whereas degenerate-type ones may also appear in spectrally nondegenerate regions. Moreover, all admissible branches in the degenerate regimes satisfy the state-transition condition and correspond to periodic-wave states, while such branches are also present in nondegenerate regimes. Direct numerical simulations of representative solutions further confirm the analytical predictions.
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General Relativity and Quantum Cosmology
Exact black hole solutions with semi-symmetric vectorial torsion
Lehel Csillag and Tiberiu Harko
Semi-Symmetric metric
gravity extends general relativity by introducing a semi-symmetric connection with vectorial torsion. The modified field equations contain extra contributions from the torsion vector and its derivatives. Assuming a purely radial torsion vector consistent with spherical
symmetry, we derive two exact
vacuum solutions. The metric depends on two integration constants, defining the Schwarzschild radius and a new cosmological-type length scale. Classical
Solar System tests, including perihelion precession, light deflection, and radar echo delay, are used to constrain the new length scale and the associated deviations from general relativity. The thermodynamic properties of the resulting black hole solutions are investigated, and it is shown that the vector perturbation sector is linearly stable.
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Instrumentation and Methods for Astrophysics
Simulating Zernike-based CWFSing with HCIPy
Klaus Subbotina Stephenson and Kate Jackson
This work explores optimal sensing distances in Zernike-based
Curvature WaveFront Sensing (CWFS). By using HCIPy, an open-source Python package, we simulate the first 100 Zernike modes at a variety of propagation distances (1 to 20,000 m) to explore the relationship between the propagation of a wavefront and its spatial complexity to understand an idealized CWFS' sensitivity to individual modes. We find that there exist distinct optimal sensing distances for low-spatial-order-modes, with high-spatial-order modes demonstrating grouping behavior at exponentially shorter optimal sensing distances. Our results indicate that there is a sensitivity gap in current CWFSing that can be resolved by resorting to a high number of sensing planes for the low spatial order regime, with one sensing plane for each individual low-order mode; similarly, we propose several high-order regime sensing planes, with each sensing plane dedicated to small groups of localized modes centered around the highest modal sensitivity at a given propagation distance. We also discuss the caveats in dealing with high-order Zernike modes and the need for carrying out further propagation analysis in the
Fourier space to extend preliminary work presented here. Lastly, we suggest the development of a new reconstruction
algorithm that weighs the ability to reconstruct a complete wavefront according to the sensitivity (gain) to each mode at an individual sensing distance.
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Quantum Physics
Lie-Algebraic Classical Simulation of Bosonic Systems Beyond Gaussian Dynamics
Adelina Bärligea, Timothy Heightman, Jakob S. Kottmann et al. (+1 more)
Classical simulability is ultimately determined by both the dynamics of a
quantum system and the observables being evaluated. Lie-algebraic simulation exploits the latter to make exact
polynomial-time classical simulations by propagating observables through low-dimensional invariant operator spaces. However, its conventional formulation in terms of
polynomial-dimensional dynamical Lie
algebras does not directly accommodate bosonic systems as their
algebras are neither compact nor semisimple. In this contribution, we overcome this limitation, making bosonic systems accessible to the Lie-algebraic programme of exact
polynomial-time classical simulation. We prove that expectation values, fixed-order correlation functions, including multi-time correlators and out-of-time-ordered correlators, and gradients are efficiently computable whenever their operator modules have
polynomial dimension. This recovers Gaussian
quantum optics and extends it to non-Gaussian input states, while identifying exact
polynomial regimes of interacting non-Gaussian dynamics including bounded-
photon Kerr and pair-hopping
Hamiltonians and nilpotent
polynomial phase dynamics. We show that unlike in the finite-dimensional
spin and fermionic setting treated previously, a finite-dimensional bosonic generator
algebra alone does not guarantee finite observable dynamics. We further derive a controlled perturbative hierarchy for squeezing beyond exact sector confinement and confirm the predicted error orders numerically. We also evaluate operator spreading on interacting chains of up to $400$ modes and connect a topological doublon band with flux-reversed edge motion. These results provide a unified formalism for classifying, discovering, and systematically approximating tractable bosonic
quantum dynamics with classical
polynomial-time simulation.
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All authors Adelina Bärligea, Timothy Heightman, Jakob S. Kottmann, Antonio Acín
High Energy Physics (Phenomenology)
Probing the Internal Structure of $X(3872)$ via Magnetic Moment: Distinguishing Color-Singlet and Compact Configurations
M. Monemzadeh and N. Tazimi
The nature of the $X(3872)$ exotic
hadron remains one of the most debated questions in
hadron spectroscopy. We calculate its
magnetic moment within a non-relativistic
quark model that includes the three-body force arising from the cubic Casimir operator of $SU(3)_C$ with consistent dimensional analysis. Unlike previous works that used an uncontrolled large coupling, we fix the three-body strength using the realistic value of $\sim 10$–$20$ MeV extracted from the recent analysis of Noh et al.~(2024) based on
lattice QCD and
baryon spectroscopy. We find that the
magnetic moment predictions fall into two distinct regions: the pure color-singlet configuration yields $\mu_X = -0.99 \pm 0.02\,\mu_N$, while the compact configurations yield $\mu_X = -1.17$ to $-1.23\,\mu_N$. The difference between the two compact scenarios ($0.06\,\mu_N$) is comparable to the systematic uncertainty of the model ($\sim 0.15\,\mu_N$) and should be interpreted with caution. However, the distinction between the pure color-singlet and the compact scenarios ($\sim 0.18$–$0.24\,\mu_N$) is larger than the estimated model systematic uncertainty and may provide a qualitative structural indicator. We emphasize that the pure color-singlet configuration is a simplified proxy for a molecule and does not represent a physical $D^0\bar{D}^{*0}$ molecule with large spatial extent. A full molecular treatment would require coupled-channel dynamics and long-range pion-exchange potentials, which are beyond the scope of this work. We also resolve a long-standing dimensional inconsistency in the cubic Casimir three-body force formulation and demonstrate through a detailed sensitivity and uncertainty analysis that our conclusions are robust for the physically relevant range of the three-body coupling.
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Materials Science
Over what length scale does an inorganic substrate perturb the structure of a glassy organic semiconductor?
Kushal Bagchi, Chuting Deng, Camille Bishop et al. (+6 more)
While the bulk structure of vapor-deposited glasses has been extensively studied, structure at buried interfaces has received little
attention, despite being important for organic electronic applications. To learn about glass structure at buried interfaces, we study the structure of vapor-deposited glasses of the organic
semiconductor DSA-Ph (1,4-di-[4-(N,N-diphenyl)amino]styryl-benzene) as a function of film thickness; structure is probed with grazing incidence X-ray scattering. We deposit on silicon and gold substrates and span a film thickness range of 10-600 nm. Our experiments demonstrate that interfacial molecular packing in vapor-deposited glasses of DSA-Ph is more disordered compared to the bulk. At a deposition temperature near room temperature, we estimate ~ 8 nm near the substrate can have modified molecular packing. Molecular dynamics simulations of a coarse-grained representation of DSA-Ph reveal a similar length scale. In both the simulations and the experiments, deposition temperature controls glass structure beyond this interfacial layer of a few nanometers.
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All authors Kushal Bagchi, Chuting Deng, Camille Bishop, Yuhui Li, Nicholas E Jackson, Lian Yu, M.F. Toney, J.J. de Pablo, M.D. Ediger
Soft Condensed Matter
Rejuvenation versus overaging: The effect of cyclic loading/unloading on the segmental dynamics of PMMA glasses
Trevor Bennin, Enran Xing, Josh Ricci et al. (+1 more)
The acceleration of structural relaxation or physical aging by deformation, known as overaging, has been reported in experiments and simulations of
polymer and colloid glasses, and correctly accounting for overaging is important for the prediction of the long-term behavior of
polymer glasses in engineering applications. Here the effects of cyclic loading/unloading on the segmental dynamics and mechanical properties of PMMA glasses are investigated using a probe reorientation technique and time-aging time superposition of the mechanical response, respectively. Sets of 5000 tensile loading/unloading cycles were performed at temperatures between Tg - 10 K and Tg - 25 K with cycle extension strains ranging from 0.003 to 0.007. After cycling, the segmental dynamics measured with the probe reorientation technique either remained unchanged or were faster relative to an undeformed sample. The relaxation times of cycled glasses recovered with a common time scale on the order of their aging time, indicating that they retain a
memory of their original age, as opposed to a full erasure of their thermal and mechanical history. Surprisingly, changes as a result of cycling were more obvious in probe reorientation measurements than in the mechanical properties, suggesting that the probe reorientation technique can sensitively detect nonlinear effects of deformation. No evidence of overaging was observed in the optical or mechanical measurements as a result of these cyclic loading/unloading experiments.
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All authors Trevor Bennin, Enran Xing, Josh Ricci, M.D. Ediger
Quantum Physics
Readout Orientation Controls Measurement-Accessible Quantum Tangent Geometry
Marwan Ait Haddou
A fixed
quantum measurement can expose substantially more tangent information than a restricted observable readout retains. We study this second restriction. For a normalized covariance $C \succeq 0$, $\mathrm{Tr} C = 1$, of measurement-induced tangent scores in an $N$-dimensional centered score space, and a rank-$r$ readout projector $P$, we quantify retained tangent mass by $R=\mathrm{Tr}(PC)$. The ratio $\rho=R/(r/N)$ separates the actual retained mass from a rank-only random-orientation reference. Standard Grassmann averaging gives $\mathbb{E}\rho=1$ and $\mathrm{Var}(\rho) \le 2/(r d_{\mathrm{eff}})$, where $d_{\mathrm{eff}}=1/\mathrm{Tr}(C^2)$. We use this identity as a null model rather than as a new random-projection
theorem. Numerically, family-balanced one- and two-body readouts remain close to the rank reference through $n=16$ even as the tangent covariance becomes strongly anisotropic. The decisive equal-rank comparison holds the
circuit, measurement record, readout rank, and evaluation shot budget fixed. For Haar-$U(4)$ at $n=12$, cross-fitted
alignment increases the mean directional gradient-energy proxy by a factor 9.584 and the finite-shot signal-to-noise ratio by a factor 3.111 relative to the physical one-body readout, while a random rank-matched subspace remains near the rank baseline. A half-filled $U(1)$-conserving family provides a structured counterexample to generic orientation: physical low-weight $Z$ readouts are already strongly aligned with leading tangent directions over the tested finite-size range. We treat this
symmetry result as a case study, not as a claim that $U(1)$
symmetry generically prevents barren plateaus or that hydrodynamics is the established mechanism. The results isolate readout orientation as a degree of freedom invisible to rank alone that directly controls how much measured tangent information remains usable after readout restriction.
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Soft Condensed Matter
Controlling Structure and Properties of Vapor-Deposited Glasses of Organic Semiconductors: Recent Advances and Challenges
Kushal Bagchi and MD Ediger
The last decade has seen great progress in manipulating the structure of vapor-deposited glasses of organic
semiconductors. By varying the substrate temperature during deposition, glasses with a wide range of density and molecular orientation can be prepared from a given molecule. We review recent studies that show the structure of vapor-deposited glasses can be tuned to significantly improve the external
quantum efficiency and lifetime of OLEDs (organic light emitting diodes). We highlight the ability of molecular simulations to reproduce experimentally observed structures, setting the stage for in-silico design of vapor-deposited glasses in the coming decade. Finally, we identify research opportunities for improving the properties of organic
semiconductors by controlling the structure of vapor-deposited glasses.
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Cosmology and Nongalactic Astrophysics
Kazuyuki Akitsu, Shi-Fan Chen and Zvonimir Vlah
Galaxy shapes are unique tensor tracers of large-scale structure, providing a promising avenue to both enhance current cosmological programs and detect new physics beyond the scalar sector. We develop a general formalism to describe the full 3D structure of
galaxy shapes and their statistics, including the breaking of isotropy by the line of sight and
redshift space distortions. We constructively show that the
redshift-space mapping generates a kinematic basis whose form factors are strictly
polynomial in the line-of-sight angle $\mu = \hat{k} \cdot \hat{n}$, and that parity selection rules restrict scalar-tensor and tensor-tensor correlators to 3 and 13 independent form factors, respectively, with the latter further reduced to 9 by exchange
symmetry. We show that this polynomiality is preserved transforming into a total helicity basis denoted by total angular momentum $M$—sourced to be nonzero by powers of the line-of-sight $\hat{n}$—and that this is equivalent to the form factors having
spin weights $(1 - \mu^2)^{|M|/2}$ and described by associated Legendre
polynomials $P^{|M|}_\ell$. We construct
estimators for form factors in the normalized total-helicity basis that provide the optimal angular weighting to extract shape information, and connect the full tensor basis to projected shape statistics. To validate our formalism, we study the above tensor form factors within a toy model, showing that all allowed channels are generated even within simplified assumptions, and apply our
estimators to
halo shape statistics in N-body simulations wherein all channels up to total angular momentum $|M| \leq 2$ are detected. We anticipate that the methods developed here will have applications ranging from optimal extraction of intrinsic-
alignments in hydrodynamical simulations to identifying new physics in tensor channels forbidden by selection rules in the standard model of cosmology.
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Instrumentation and Methods for Astrophysics
The Roman Coronagraph Community Participation Program: trials and triumphs of designing an observing program for a technology demonstration instrument
Schuyler G. Wolff, Vanessa P. Bailey, Justin Hom et al. (+19 more)
The Coronagraph Instrument onboard the Nancy Grace Roman Space
Telescope serves as a crucial technology pathfinder for the Habitable Worlds Observatory, with on-sky verification of high-contrast imaging techniques and the potential to image a Jupiter analog in reflected light for the first time. Together with the Roman Project Team, the Community Participation Program (CPP) is responsible for target selection, preparatory observations, developing an exposure time calculator, target database, data reduction pipeline, simulation tools, and engagement with the broader community. Here we present an overview of the CPP activities over the past two years with an emphasis on observation planning activities for the initial in-orbit checkout and the first six months of the observation phase. Finally, we present future opportunities for the astronomical community to interact with the data as it becomes public early in the mission.
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All authors Schuyler G. Wolff, Vanessa P. Bailey, Justin Hom, Beth Biller, Dmitry Savransky, Julien H. Girard, Ellis Bogat, Óscar Carrión-González, Clarissa R. Do Ó, Masayuki Kuzuhara, Chen Xie, Maxwell Millar-Blanchaer, Susan Redmond, Johan Mazoyer, Macarena Vega-Pallauta, Gael Chauvin, Matthieu Ravet, Alexandra Greenbaum, Eric Cady, Ramya Anche, James Ingalls, the Roman Coronagraph Community Participation Program Team
Quantum Gases
Hidden Ergodic Relaxation in the Quench Dynamics of a Bichromatic Mott Lattice
Áttis V. M. Marino, Rhombik Roy, M. A. Caracanhas et al. (+5 more)
We investigate the nonequilibrium dynamics of strongly interacting
bosons in a finite bichromatic Mott
lattice following a sudden quench of the secondary
lattice amplitude. The coefficient
entropies and second Rényi
entropy exhibit pronounced growth toward their Gaussian Orthogonal Ensemble (GOE) predictions from random-
matrix theory, consistent with GOE-like statistical spreading in the employed multiconfigurational representation. In striking contrast, experimentally accessible observables, including the momentum distribution, fragmentation, and Glauber correlation functions, remain nearly unchanged throughout the
evolution. For the sampled strong quenches, the coefficient
entropies, second Rényi
entropy, and the $N$-body coefficient spreading collapse onto a common relaxation trajectory that becomes largely independent of the perturbation strength. Our results reveal an emergent hidden ergodic relaxation beneath the persistent local Mott-like order. An effective embedded random-
matrix model captures the qualitative crossover from restricted to extensive
Hilbert-space spreading, providing an interpretive framework for the observed relaxation dynamics.
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All authors Áttis V. M. Marino, Rhombik Roy, M. A. Caracanhas, N. D. Chavda, Antônio M. S. Macêdo, V. S. Bagnato, Robin P Sagar, B. Chakrabarti
Quantum Physics
Aditya Kumar and Sumit Chongder
Federated deployments of variational
quantum classifiers are attractive for cross-organisation risk prediction in supply chains, because raw data never leaves the client, yet data-protection regulations such as the GDPR grant clients a right to request that their contribution be removed from a trained model after the fact. Retraining a
federated model from scratch to honour such a request is correct but wasteful, and it is not obvious which
quantum circuit parameters actually carry a given client's influence. We introduce
Entanglement-Weighted
Pruning (EWP), an unlearning procedure for
quantum federated learning that scores every trainable
circuit parameter with the product of two signals: the diagonal entry of the
quantum Fisher information
matrix estimated on the target client's data via the parameter-shift rule, and a structural
entanglement weight associated with the parameter's gate. Parameters with the lowest scores are pruned, optionally followed by a short fine-tuning pass on the retained clients. We implement the full pipeline in Qiskit for a four-
qubit data-re-uploading ansatz trained with FedAvg across five simulated supply-chain-risk clients, and
benchmark EWP against full retraining, fine-tuning alone, random
pruning, Fisher-only
pruning, and
entanglement-only
pruning, over three random seeds. EWP attains a mean post-unlearning accuracy statistically indistinguishable from the full-retraining oracle, while producing a lower forgetting score and requiring roughly 16 times less wall-clock time. Ablations over
pruning threshold, client count, and non-IID strength show that combining the two signals is necessary, as
entanglement-only and Fisher-only
pruning each substantially degrade accuracy relative to EWP.
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Quantum Physics
Exact Moments of Gaussian Gram Hafnians Reveal an $n^2/\log n$ Threshold for Weak Anticoncentration
Hongru Zhao
Anticoncentration is central to hardness arguments for approximate sampling. In the independent Gaussian surrogate for collision free Gaussian
boson sampling, the moment ratio studied here also determines the averaged ideal linear cross
entropy reference value. Let $H_{k,n}=\mathrm{haf}(X^{\mathsf T}X)$, where $X\in\mathbb{C}^{k\times 2n}$ has independent standard circular complex Gaussian entries. We evaluate $\mathbb{E}|H_{k,n}|^2$ and $\mathbb{E}|H_{k,n}|^4$ exactly by reducing four hafnian copies to a rank two Gaussian integral. For $R_{k,n}=(\mathbb{E}|H_{k,n}|^2)^2/\mathbb{E}|H_{k,n}|^4$, we obtain $R_{k,n}=4^{-n}\binom{2n}{n}/F_{k,n}$, where $F_{k,n}={}3F_2(-n,-n,1/2;1,k/2;1)$ is a terminating generalized hypergeometric
polynomial. If $k/n^2\to c>0$, then $F{k,n}\to e^{1/c}I_0(1/c)$, where $I_0$ is the modified Bessel function of the first kind of order zero, and consequently $R_{k,n}\sqrt{\pi n}\to[e^{1/c}I_0(1/c)]^{-1}$. Thus $k\asymp n^2$ is a smooth Bessel crossover, whereas the scaling order boundary for inverse
polynomial weak anticoncentration is $k\asymp n^2/\log n$. These conclusions concern the Gaussian surrogate moment criterion; finite dimensional Haar moment transfer and high probability small ball anticoncentration remain separate problems.
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High Energy Physics (Theory)
Robin boundary conditions in global AdS$_4$: exact double-trace thermodynamics and a soft-mode instability
David A. Lowe and Juanyi Yang
We consider a conformally coupled scalar field in four-dimensional global anti-de Sitter space with Robin boundary conditions, parametrized by an angle $\alpha$. On the boundary cylinder $\mathbb{R}\times S^{2}$ these conditions realize the double-trace deformation $\tfrac12\lambda\!\int O^{2}$ of the dimension-one operator $O$ in the alternate quantization with $\lambda=\cot\alpha/L$. Because the conformal map to one half of the Einstein static universe is exact, the boundary integral equation can be diagonalized, and the deformed two-point function follows in closed form, $\widehat{\mathcal G}_{\alpha}=\widehat{\mathcal G}_{N}/(1+\lambda\widehat{\mathcal G}_{N})$. Its poles give the normal-mode spectrum, and its determinant gives the free energy exactly within this Gaussian sector. After three local boundary counterterms, the Casimir energy reaches the stability endpoint with a finite square-root cusp. At any finite coupling the bulk $T^{4}$ and $T^{3}$ terms are independent of $\alpha$ and cancel in the difference from Neumann, leaving $\tfrac{\pi}{3}\cot\alpha\,LT^{2}$ as the leading $\alpha$-dependent term. All nonanalyticity comes from one static homogeneous mode, which becomes soft at $\alpha_{\rm crit}$, in agreement with the known classical stability threshold. The susceptibility diverges with exponent $\gamma=1$ and the gap closes with exponent $1/2$. Beyond this angle the mode is tachyonic, and a stable phase would require a stabilizing interaction. In the flat-space limit the physical coupling scales to zero at fixed energy, so the Robin dependence survives only in the soft-frequency sector, which we characterize by a meromorphic Mellin transform in the boost weight. The Robin angle thus gives a control parameter for a Gaussian stability endpoint that can be followed exactly, and raises the analogous question for relaxed boundary conditions in AdS
gravity.
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Fluid Dynamics
Turbulent Microscale Flow Field Prediction In Porous Media Using Convolutional Neural Networks
Vishal Srikanth, Ching-Wei Huang, Ryan Harradine et al. (+1 more)
Turbulence modeling in porous media can be greatly improved by combining high-resolution numerical methods with modern data-driven techniques. The development of accurate macroscale models (length scale greater than the pore size) will enable real-time systemic simulations of porous media flow. We consider the case of turbulent flow in homogeneous porous media, typically encountered in engineered porous media (heat exchangers, metamaterials, combustors, etc.). The underlying microscale flow field is inhomogeneous and determined by the geometry of the porous medium. Neural Networks are able to resolve the geometry-dependence and the non-linearity of porous media turbulent flow. We are proposing to separate the macroscale model into individual blocks that predict a unique aspect of the microscale flow, such as microscale spatial flow distribution and
vortex dynamics. In the present work, we determine the feasibility of the prediction of the Reynolds-averaged microscale flow patterns by using Convolutional Neural Networks (CNN). The porous medium is represented by using a square
lattice arrangement of circular cylinder solid obstacles. The pore-scale Reynolds number of the flow is 300. The porosity of the porous medium is varied from 0.45 to 0.92 with 60 steps. The microscale flow field is simulated by using Large Eddy Simulation (LES) with a compact sixth-order finite difference method. We demonstrate satisfactory prediction of the microscale flow field using the CNN with a global error less than 10%. We vary the number of training samples to study the deterioration of the model accuracy. The CNN model offers a O(106) speedup over LES with only 10% loss in accuracy.
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All authors Vishal Srikanth, Ching-Wei Huang, Ryan Harradine, Andrey V. Kuznetsov
Mesoscale and Nanoscale Physics
Emissivity by Design: Geometric Mesh Inductance Governs Thermal Radiation in Metallic Nanowire Networks
Amaury Baret and Ngoc Duy Nguyen
The thermal infrared emissivity of metallic nanowire networks - the property that makes them candidate low-emissivity transparent electrodes - follows regularities that have resisted physical explanation: a strong wire-diameter dependence with no wire-length dependence, a correlation with sheet resistance that breaks down above ~15 ohm/sq, and an angular signature that turns from dielectric-like to metallic as the network densifies. We show that all of them follow from one local
geometric length, the average inter-wire gap g, acting through the
geometric inductance of a mesh finer than the thermal wavelength: $X_L = Z_0 (g/\lambda) \ln(2g/\pi D)$, a parameter-free reactance that exceeds the ohmic loss and, unlike the DC sheet resistance, stays finite instead of diverging at the percolation threshold. Since the gap is fixed by areal density and wire diameter alone, the optics is length-independent and decoupled from percolative transport; what has been read as a second, optical percolation is instead a smooth impedance crossing. With a single fitted parameter the theory reproduces 56 silver-nanowire samples across four diameters to a mean absolute error of 0.04, collapses them onto one universal curve, and - unchanged - predicts the emissivity-transmittance data of five independent groups and the measured spectral emissivity, including the silica
phonon band. Because this reactance contains no material constant, the inter-wire gap emerges as the master design variable for the radiative properties of metallic nanowire transparent conductors.
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Nuclear Experiment
Determination of Tritium Content in D2 Gas and Heavy Water
Sandeep Puri, Noah D'Amico, Ian Jones et al. (+4 more)
A simple experimental method for the determination of tritium concentration in natural hydrogen and deuterium gas down to the femtomole level is described. Palladium and platinum catalysts were used to react hydrogen and oxygen, creating water that could be analyzed in a Revvity Quantulus GCT 6220. This analysis produced sub-femtomole detection limits of tritium present in hydrogen gas or heavy water. A contamination level of $\sim 1\text{ femtomole/SL}$ was found in the $\text{D}_2$ gas sample that was analyzed. A contamination level of $\sim 0.025\text{ femtomole/SL}$, which is below the noise level of the Quantulus, was found in the standard hydrogen gas sample that was analyzed. The choice of palladium or platinum catalyst did not significantly affect the resulting tritium measurement. By showing that common $\text{D}_2$ samples can be contaminated with trace amounts of tritium orders of magnitude above natural abundance, this test demonstrates that a baseline tritium measurement for deuterium samples is highly important for determining the validity of results in
nuclear fusion yield experiments.
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All authors Sandeep Puri, Noah D'Amico, Ian Jones, Sonny Alaniz, Andrew Gillespie, Cuikun Lin, R. V. Duncan
General Relativity and Quantum Cosmology
Wormhole Reconstruction in Non-Conservative Unimodular Gravity: Ricci Scalar as an Independently Prescribed Curvature Profile
Marcelo H. Alvarenga, Rodrigo Santos Bufalo and Júlio C. Fabris
The absence of an algebraic relation between the
Ricci scalar and the trace of the energy-momentum tensor in Non-Conservative Unimodular
Gravity ($\mathrm{NUG}$) opens new possibilities for constructing spacetime geometries from prescribed
curvature profiles. Exploiting this property, we develop a
curvature reconstruction framework in which traversable wormhole geometries are generated directly from a prescribed
curvature profile rather than from the matter sector or the metric functions. The reconstruction procedure is implemented for a power-law
Ricci scalar combined with three different
redshift functions, leading to distinct classes of static and spherically symmetric wormhole solutions. We investigate their geometrical properties, asymptotic behavior and null energy condition. Although the radial null energy condition remains necessarily violated at the throat, we show that the dimensionless
curvature parameter controls the intensity of the exotic matter supporting the wormhole, while the
curvature exponent determines the global asymptotic structure of the reconstructed spacetime. In particular, the critical configuration separating asymptotically flat solutions from geometries with residual asymptotic deformation naturally emerges from the reconstruction scheme. These results establish
curvature reconstruction from prescribed
Ricci scalar profiles as a viable geometrical framework for generating compact-object spacetimes within non-conservative unimodular
gravity.
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Instrumentation and Methods for Astrophysics
The Roman Coronagraph Community Participation Program: pre-launch reference star list and impact of reference star properties on post-processing performance
Justin Hom, Schuyler G. Wolff, Jessica Gersh-Range et al. (+51 more)
The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory (HWO) that aims to directly image and characterize habitable exoEarths. The nominal Roman Coronagraph observing plan involves alternating observations of a science target and a bright, nearby reference
star for both wavefront calibration and reference differential imaging post-processing. Reference
star criteria for the most demanding coronagraph mode are restrictive, limiting the sample to only 40 candidates for which thorough observational vetting is needed to assess their suitability. Reference
star properties such as resolved diameters, presence of circumstellar
dust, and close point sources may also have more subtle impacts on post-processing efficacy that may inhibit final contrast performance. In this work, we describe the current progress of the CoronaGraph Instrument Reference
stars for
Exoplanets (CorGI-REx) observing campaign, a 300+-hour observing campaign that utilizes instruments from around the world to vet reference
stars for high-order wavefront control suitability. We will present the pre-launch list of reference
star candidates being utilized for the Roman Coronagraph Observation Phase constructed from a thorough analysis of high contrast and interferometric observations. We will also present the results of simulations investigating the impact of reference
star resolved diameters and companions on post-processing performance. We conclude by discussing the importance of reference
star selection for scheduling observations and optimizing contrast performance for the Roman Coronagraph along with implications for HWO coronagraph operations.
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All authors Justin Hom, Schuyler G. Wolff, Jessica Gersh-Range, Ramya M. Anche, Vanessa P. Bailey, Jean-Philippe Berger, Beth A. Biller, Wolfgang Brandner, Marah Brinjikji, Gaël Chauvin, David R. Ciardi, Catherine A. Clark, Laird M. Close, Robert J. De Rosa, Sarah Deveny, Warren B. Foster, Julien H. Girard, Alexandra Z. Greenbaum, Olivier Guyon, Sebastiaan Y. Haffert, Alexander D. Hedglen, Steve B. Howell, Parker T. Johnson, Maggie Y. Kautz, Jay K. Kueny, Masayuki Kuzuhara, Manon Lallement, Rico Landman, Colin Littlefield, Jean-Baptiste Le Bouquin, Jialin Li, Joshua Liberman, Joseph D. Long, Miles Lucas, Jennifer Lumbres, Bruce Macintosh, Jared R. Males, Eric Mamajek, Matthijs Mars, Eden A. McEwen, Avalon L. McLeod, Maxwell A. Millar-Blanchaer, Toshiyuki Mizuki, Sophie Noiret, Tiffany Nguyen, Lauren Schatz, Nicholas T. Schragal, Adam K. Taras, Elena Tonucci, Katie Twitchell, Kyle Van Gorkom, Macarena C. Vega-Pallauta, Jason J. Wang, Jingwen Zhang
Nuclear Experiment
Accurate Charge Radius Measurement of $^{14}$C Confronts Ab Initio Theory
Kristian König, Patrick Müller, Tobias Gesser et al. (+11 more)
Located at the
neutron shell closure $N = 8$, the long-lived radioactive isotope $^{14}$C plays a critical role in geochronology and
nuclear structure studies. Despite its widespread use, the
nuclear charge radius of $^{14}$C has remained less precisely known compared to its stable counterpart $^{12}$C. Here, we report a high-precision determination of the $^{14}$C charge radius using collinear
laser spectroscopy at the COALA setup at TU Darmstadt, improving upon the precision of previous muonic measurements by a factor $5$ and revealing a $1.9\sigma$ discrepancy of combined uncertainty, indicating a likely underestimated uncertainty in the muonic determination. This measurement challenges state-of-the-art ab initio
nuclear theory calculations, including auxiliary field
diffusion Monte Carlo, the valence-space in-medium similarity renormalization group, and the no-core shell model, augmented by neural-network techniques. With $^{12}$C and $^{14}$C now forming one of the most precisely characterized even-even isotope pairs, these results also enable improved QED tests.
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All authors Kristian König, Patrick Müller, Tobias Gesser, Emily Burbach, Stefano Gandolfi, Matthias Heinz, Phillip Imgram, Alessandro Lovato, Pieter Maris, Takayuki Miyagi, Wilfried Nörtershäuser, Robert Roth, Julien Spahn, Achim Schwenk
Instrumentation and Methods for Astrophysics
pynucastro 3: A community library for nuclear astrophysics
Zhi Chen, Khanak Bhargava, Eric T. Johnson et al. (+8 more)
We describe the latest release of pynucastro: a community python library for
nuclear astrophysics. The goal of the pynucastro project is to build the tools needed to interactively explore
nuclear properties, reaction rates, and networks, and to export these networks to a variety of simulation codes. Major changes in pynucastro since the last major release include new rate approximations, a
stellar equation of state, support for the StarLib library and rate uncertainties, and new tools for exploring networks.
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All authors Zhi Chen, Khanak Bhargava, Eric T. Johnson, Reth Lopes, Melissa Rasmussen, Alexander Smith Clark, Michael Zingale, Brendan Boyd, Kiran Eiden, Sam Glosser, Don E. Willcox