Quantum Physics
Induced random mixed states are symmetric Dirichlet mixtures
Brian T. Kirby, Alexander C. B. Greenwood, Sanjaya Lohani et al. (+1 more)
We establish an exact equivalence in distribution between $D$-dimensional random mixed states induced by partial traces over $K$-dimensional environments and the Mai-Alquier distribution, a mixture of $K$ independent Haar-random pure states weighted by a symmetric Dirichlet distribution. This identification recasts a class of expectation values for induced ensembles into calculations involving Dirichlet moments and low-order Haar averages on a single-system state space. As applications, we recover exact purity moments up to fourth order, derive the mean
Hilbert–Schmidt distance between independent induced ensembles with possibly different environment dimensions, and obtain exact average determinants. These results provide a unified and constructive perspective on induced random mixed states and on the evaluation of quantities such as purity moments, overlaps, and determinants.
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All authors Brian T. Kirby, Alexander C. B. Greenwood, Sanjaya Lohani, Joseph M. Lukens
General Relativity and Quantum Cosmology
Perturbations of Charged Black Holes with Higher-Order Interactions
Oleksandr S. Stashko, Roman A. Konoplya and Mark P. Hertzberg
We study linear gravitational perturbations and the corresponding quasinormal-mode spectra of electrically and magnetically charged black holes in the presence of higher-order corrections to the Einstein-
Hilbert action. In particular, we consider a four-derivative interaction that couples the Riemann tensor to the electromagnetic field strength in the unique (Horndeski) combination that preserves second-order equations of motion. We provide a comprehensive analysis of the stability conditions. We numerically confirm the absence of exponentially growing modes throughout the physically admissible region of parameter space where the theory remains free of pathologies. We then investigate in detail the properties of the quasinormal-mode spectra and identify several distinctive features induced by the higher-order interaction.
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General Relativity and Quantum Cosmology · Cross-listed from math.DG
Area-constrained Willmore surfaces in Lorentzian manifolds: curvature inequalities and the Hawking quasi-local energy
Alejandro Peñuela Diaz
We develop an area-constrained Willmore theory for closed spacelike surfaces in four-dimensional Lorentzian
manifolds. Since the Euler–Lagrange equation is normal-bundle-valued, we introduce directional criticality along a prescribed normal direction and identify a class of connection-compatible directions determined by the normal connection. Our main result is the sharp inequality $2\lambda|\Sigma|+\int_\Sigma |\vec H|^2,d\mu\leq 8\pi\chi(\Sigma)$ for criticality in a connection-compatible spacelike direction under an Einstein-tensor sign condition. Under the dominant energy condition and $\lambda\geq0$, this yields $\int_\Sigma |\vec H|^2,d\mu\leq16\pi$. Equality is rigid: $\Sigma$ is round and satisfies Minkowski causal-diamond
rigidity. We also prove an analogous sharp inequality for null critical directions. These results give positivity,
rigidity, stationarity, and infinitesimal monotonicity statements for the Hawking quasi-local energy. A hypersurface formulation recovers the previously studied Hawking-surface problem as criticality in the spatial normal direction. Explicit examples in spherical
symmetry, Kerr, and FLRW spacetimes distinguish directional from full criticality and show the necessity of the sign assumptions in the
rigidity theory.
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Instrumentation and Detectors
Intrinsic time resolution of a hexagonal BC404 scintillator: A Monte Carlo study of interaction geometry and optical reflectivity
C. H. Zepeda-Fernández, L.F. Rebolledo-Herrera and E. Moreno Barbosa
Time resolution is an important parameter in particle detectors, as it determines their ability to distinguish between two temporally separated events. It can be decomposed into electronic and intrinsic contributions, the latter being influenced by scintillation, optical transport, detector geometry, particle type and energy, and the sensitive area of the photosensor. In this work, a Monte Carlo simulation based on Geant4 is used to investigate the intrinsic time resolution of a hexagonal BC404 plastic scintillator. The analysis includes the evaluation of the optical-
photon distribution over the hexagonal surfaces and the characterization of the intrinsic time resolution for different interaction configurations. The intrinsic time resolution is investigated using
muons as
cosmic-ray proxies with energies ranging from 4~GeV to 1~TeV. In addition, the effect of surface reflectivity on optical-
photon transport and timing performance is studied for reflectivities ranging from 0% to 100%. The results show that the intrinsic time resolution exhibits little dependence on the incident
muon energy, while a clear dependence on the interaction position is observed. Furthermore, although the number of detected
photons varies with the interaction position and surface reflectivity, the intrinsic time resolution is not solely determined by
photon statistics, indicating that optical transport and geometrical effects play an important role in the timing performance. Across the investigated configurations, intrinsic time resolutions ranging from approximately 15 to 100~ps are obtained. These findings highlight the importance of the interaction position, optical transport,
photon statistics, and surface reflectivity in determining the timing performance of hexagonal plastic scintillators and provide guidance for the optimization of their optical properties and geometry for timing-sensitive applications.
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Nuclear Experiment
Detailed experimental study of excited states in $^{50}$Ti via the $(d,p)$ and $(d,p\gamma)$ reactions
B. Kelly, M. Spieker, L. T. Baby et al. (+7 more)
Excited states of semi-magic $^{50}$Ti were studied up to the
neutron-separation energy via the $(d,p)$ and $(d,p\gamma)$ reactions. In total, 82 excited states were identified based on the measurement of angular distributions with the Super-Enge Split-Pole Spectrograph (SE-SPS) at Florida State University. From the experimental data, sum rules related to vacancies were calculated for the $2p_{3/2}$, $2p_{1/2}$, $1f_{5/2}$, $1g_{9/2}$, and $2d_{5/2}$
neutron single-particle orbitals and compared to predictions obtained with the time-dependent continuum shell model (TDCSM), the quasiparticle-
phonon model (QPM), and the relativistic equation of motion theory (REOM$^3$). A comparison for the $(d,p)$ data obtained for $^{51}$Ti and $^{50}$Ti is also presented, focusing on differences of the single-particle strength fragmentation in even-$A$ and odd-$A$
nuclei.
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All authors B. Kelly, M. Spieker, L. T. Baby, S. Baker, A. L. Conley, D. Houlihan, K. W. Kemper, E. Litvinova, N. Tsoneva, A. Volya
Astrophysics of Galaxies
TDCOSMO XXX: Spatially resolved kinematics of the deflectors in time-delay lens systems B1608+656 and SDSSJ1206+4332 from JWST-NIRSpec observation
Pritom Mozumdar, Shawn Knabel, Anowar J. Shajib et al. (+3 more)
We present spatially resolved
stellar kinematics of the deflector
galaxies in two time-delay lens systems, B1608+656 and SDSS J1206+4332, measured from JWST NIRSpec integral field spectroscopy. B1608+656 is a quadruply imaged
quasar lensed by a pair of tidally interacting
galaxies, the primary deflector (G1) and a close companion (G2), for which we quantified G2's
tidal influence on G1 and define a criterion identifying the region where this perturbation is negligible and standard Jeans-equation modeling remains valid. SDSS J1206+4332 is a doubly imaged
quasar whose extended host
galaxy is itself quadruply imaged by a foreground massive
galaxy (G0), accompanied by a fainter perturber (G1). For both systems, we report the first spectroscopic
redshift and velocity dispersion measurements of the perturber
galaxies. For G2 in B1608+656, we measure {\sigma}_v = 188 +/- 7 (stat.) +/- 2 (sys.) km/s at z = 0.6307, identical to the
redshift of the main deflector G1. For G1 in SDSS J1206+4332, we find {\sigma}_v = 100 +/- 21 (stat.) +/- 2 (sys.) km/s at z = 0.7403, slightly lower than the primary deflector G0. The resolved velocity maps of both primary deflectors show clear rotation signatures and we visually classify them as fast or regular rotators. The data products will be made publicly available and will be combined with time delays, lens models, and line-of-sight convergence to measure cosmological parameters in the upcoming TDCOSMO 2026 milestone publication.
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All authors Pritom Mozumdar, Shawn Knabel, Anowar J. Shajib, Tommaso Treu, Michele Cappellari, Aymeric Galan
Plasma Physics
RF-Specific Tungsten Erosion and Global Transport in ITER under Neon Seeding
Atul Kumar, Dhyanjyoti Nath, Wouter Tierens et al. (+15 more)
Ion cyclotron
radio-frequency heating (ICRH) is a key auxiliary heating system in ITER, but high-power RF operation can enhance
plasma-material interactions through rectified RF sheath potentials on
antenna structures and nearby
plasma-facing components. We present the first predictive application of the STRIPE (Simulated Transport of RF
Impurity Production and Emission) framework to assess RF sheath-driven tungsten (W) erosion and global
impurity transport from the ITER ICRH
antenna under ITER-relevant neon-seeded conditions. STRIPE couples SOLPS-ITER
plasma backgrounds, full-wave RF sheath calculations, geometry-specific ion energy-angle distributions, sputtering physics, and three-dimensional
impurity transport. Simulations predict RF sheath potentials of 1 to 3 kV on
antenna limiter sidewalls, increasing gross W erosion by about a factor of 64 relative to thermal sheath conditions and producing a gross source of 3.34e18 W atoms per second. Erosion is governed by RF-modified ion energy-angle distributions together with local
plasma flux rather than sheath voltage alone. About 10 percent of sputtered W is locally redeposited, giving a net source of 3.01e18 W atoms per second. The RF-induced
antenna source remains about three orders of magnitude smaller than the thermal divertor source and more than two orders of magnitude smaller than the integrated thermal main-chamber source. After 100 ms, about 22 percent of the mobile W inventory resides within the SOLPS-covered confined-
plasma region, corresponding to an annular W concentration of 1.70e-6. These results indicate that the ITER ICRH
antenna is unlikely to dominate the total W source budget under the conditions considered and demonstrate the need for coupled modeling of RF waves, sheaths, sputtering, redeposition, and global
impurity transport.
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All authors Atul Kumar, Dhyanjyoti Nath, Wouter Tierens, Jeremy D. Lore, Andrei Pshenov, Tom Wauters, Andrea Galvan, Davide Curreli, Syun'ichi Shiraiwa, Nicola Bertelli, Guillaume Urbanczyk, Sebastijan Brezinsek, Onkar Sahni, Mark Shephard, Walid Helou, Xavier Bonnin, Klaus Schmid, Volodymyr Bobkov
Quantum Physics
Balancing Expressivity and Overfitting in Quantum Gaussian Process Regression
Saasha Joshi, Udson C. Mendes and Luke C. G. Govia
Active learning is a paradigm of machine learning that can be utilized to model expensive black-box functions by training a surrogate model from actively queried training points. The performance of this framework depends heavily on the choice of the surrogate model. When the surrogate is Gaussian Process Regression (GPR), its performance is largely determined by the expressivity of the underlying kernel. In this work, we investigate the peculiarities of using a
quantum kernel to change the computational dynamics of active learning with GPR, focusing on the sensitivity to regularization by hyperparameter tuning. While generic, unstructured kernels suffer from exponential concentration at large scale, we empirically demonstrate that even at small scale overfitting can collapse GPR performance. Kernel regularization can be used to counteract this effect, but due to the smoothness of the
quantum fidelity kernel, regularization must be carefully chosen to balance expressivity and overfitting. Our qualitative results transfer to the practical application of restricted
quantum kernels designed to avoid exponential concentration and also present the kinds of noise that may be valuable to kernel training in near-term
quantum devices.
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Soft Condensed Matter
A force model for dense granular flows and particle segregation
M.P. van Schrojenstein Lantman
Dense granular flows are a common occurrence throughout nature and industry, but still exhibit phenomena that are not fully understood. One of these phenomena is the segregation of particles that constitute a dense granular flow, where particles separate due to differences in properties such as size and density. This work approaches segregation from a new perspective by developing a force model for a single particle based on the observation that there are two opposing drag forces acting on the particle. Validation of the model in mono-disperse flows reveals a family of velocity profiles, including a Bagnold profile. Further validation is done by comparing with known particle scaling laws in literature. The force model shows that the mechanism of segregation is always present in dense granular flows and that mono-disperse flows are a unique case where it is not distinctly visible. The insights in this paper prove a fundamental new way of thinking about dense granular flows and its individual particles, opening the field for new research directions.
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High Energy Physics (Phenomenology)
Heavy Higgsino Interpretation of the LZ Event
Kevin Langhoff
The LZ experiment has recently reported a $248$ keV
nuclear recoil event in a region where backgrounds are expected to be low. A pure higgsino scattering inelastically through a $Z$-
boson is an exciting possible interpretation of this event, but at the mass required for thermal freeze-out to account for all dark matter, $m_\chi = 1.1$ TeV, it predicts several events in the empty high-energy sideband corresponding to $E_R\gtrsim350$ keV and is further excluded by searches for high energy
neutrinos coming from the Sun by the IceCube detector. We fit the higgsino mass scale and neutral state mass splitting, $m_\chi$ and $\delta$, to the event and the empty sideband. We additionally recompute
solar capture bounds as a function of $m_\chi$. The LZ data alone are best fit at low mass, $m_\chi \approx (240,\,450)$ GeV, but is excluded by
solar capture. The parameter space most consistent with the event, the empty sideband and the
solar capture bound is $m_\chi \approx (10^5,\,10^6) $ GeV with $\delta \approx (330,\,480)$ keV, with some dependence on DM
halo modeling. Such a higgsino must be produced by some other method than standard freeze-out; this can be achieved by freezing-out during a period of early matter domination which ends by reheating the universe to temperature $T_{\rm RH}\approx 1$ TeV. We give a simple proof of concept model which does this via a Kim-Nilles mechanism and therefore connects to the origin of the Higgsino mass scale and solves the strong CP problem.
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Strongly Correlated Electrons
Emergent Electronic Bond-Order Wave in a Quasi-One-Dimensional Chain
Honghao Wang, Tristan R. Cao, Pedro Schlottmann et al. (+1 more)
Collective order is notoriously difficult to stabilize in one dimension, where strong fluctuations suppress
symmetry-breaking states. Here we report the emergence of an electronic bond-order wave (BOW) in the quasi-one-dimensional (1D) material Ba9Rh8O24, in which structural bonds become active electronic degrees of freedom that overcome 1D fluctuations to establish long-range order. Single-
crystal X-ray diffraction uncovers a striking inversion of inequivalent Rh-Rh bonds across a transition TA = 180 K, where short and long bonds interchange their identities rather than undergoing conventional Peierls dimerization. This bond inversion coincides with a heat-capacity anomaly and a profound reorganization of the dielectric response with strong suppression of dielectric loss upon cooling. The BOW exhibits strongly nonlinear, frequency-dependent I-V characteristics, clockwise hysteresis, and nonvolatile memristive switching. These findings uncover an unprecedented transformation from a dynamic bond
liquid to a rigid yet electrically reconfigurable BOW, establishing bond-centered electronic order as a new organizing principle for 1D
quantum matter.
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All authors Honghao Wang, Tristan R. Cao, Pedro Schlottmann, Gang Cao
Earth and Planetary Astrophysics
Beyond Pebble Isolation: Diverse Pathways to Giant Planet Formation Across Stellar and Orbital Scales
Lorenzo Peerani, Sho Shibata and Ravit Helled
Context.
Giant planet formation requires reaching crossover mass, i.e., when the mass of the gaseous envelope becomes equal to the mass of the core, within the disc's lifetime. The formation process depends critically on the orbital distance and
stellar mass. Aims. We simulate
planet formation via pebble
accretion up to crossover mass around
stellar hosts with masses of 0.1-1.5 Msun, considering a range of formation locations, with and without Type I migration. Methods. We use a modified version of MESA that couples pebble
accretion, gas
accretion, and disc
evolution. Results. We find that cold/warm Jupiters form, whereas in-situ formation fails at short orbital separations: viscous heating raises the isolation mass enough to assemble adequate cores, but the accompanying high disc's temperature prevents cooling and suppresses gas
giant formation. This supports migration-based explanations for the origin of hot Jupiters. At large orbital distances, crossover can be reached before pebble isolation mass. This is possible due to efficient envelope contraction in the cold, low-opacity outer disc. Inferred core masses at crossover range between 0.7 and 20 M_Earth. Conclusions. Pebble
accretion accommodates multiple formation pathways.
Giant planets can also have very small cores. Overall, different formation conditions significantly influence planetary growth and can explain the diversity in compositions and internal structures observed in the
exoplanet population.
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General Relativity and Quantum Cosmology
Gravitational Radiation from Shockwave Scattering in the Self-Force EFT
Emanuele Rosi
We investigate the high-energy collision of two spinless bodies within the Self-Force Effective Field Theory (EFT), taking one of them to be massless and highly energetic, such that it generates a gravitational shockwave (GSW) background. The GSW is perturbed by the second body, either massless or massive, satisfying respectively $E_2/E_1\ll1$ or $m_2/E_1\ll1$. Although the Self-Force expansion for shockwaves is frame-dependent, we freely choose a frame in which this EFT manifests its power, obtaining results valid to all orders in Newton's constant that make the underlying resummation patterns evident. Specifically, we push the expansion to 1SF order and prove the all-order vanishing of the so-called
recoil operators in light-cone gauge. We obtain the exact graviton propagator on the shockwave background, matching previous results, and use it to compute the on-shell waveform at 1SF order in momentum space, specialising to the massless-massless collision. The waveform is computed to all orders in the Post-Minkowskian, or weak-field, expansion. In the trans-Planckian regime, its resummed form is proved to yield a UV-finite angular spectrum of radiated energy.
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Strongly Correlated Electrons
Tuning Charge Density Wave transitions through lattice strain in NbSe3
Antoine Gallo Frantz, Aleksander Sinchenko, Luc Ortega et al. (+7 more)
The Charge Density Wave (CDW) state is a perfect example of a combined structural and electronic state, both characterized by a periodic
lattice distortion and an electronic modulation of condensed electrons, resulting from electron-
phonon coupling. They are thus prone to be tuned by
lattice strain. NbSe3 is a prototypical example of CDW states, with a chain-like structure displaying two CDWs at 145K and 59K, with wavevectors along and inclined with respect to the chain axis b. Here, we report on the
evolution of the
lattice structure and CDW properties in the quasi-one-dimensional charge-density-wave system NbSe3 under tensile stresses applied along and perpendicular to the chains axis b by a combination of X-ray diffraction and transport measurements. We find that the
lattice structure show exotic Poissons coefficients and strongly anisotropic Youngs
moduli while the
evolution of the electrical resistance demonstrates shifts of both charge-density-wave critical temperatures that are strongly correlated with the
lattice parameters. The two CDW transitions display different behaviours under applied stresses, and suggest that a modification of the band
curvature leads to the observed transport signatures.
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All authors Antoine Gallo Frantz, Aleksander Sinchenko, Luc Ortega, Pavel Grigoriev, Vladislav Kochev, Pierre Godard, Pierre Olivier Renault, Dominique Thiaudiere, David Le Bolloch, Vincent Jacques
Quantum Physics
Non-Multiplicativity of the Holevo Barycenter of Quantum Channels
Sayantan Chakraborty, Stefano Mancini, Leonardo Rossetti et al. (+1 more)
The Holevo barycenter of a
quantum channel is the unique output state obtained as the average output of any ensemble achieving the Holevo capacity. Given two
quantum channels, the multiplicativity problem asks whether this barycenter tensorizes under parallel composition, namely whether the barycenter of the product channel coincides with the tensor product of the individual barycenters. This question is closely related to the additivity problem for the Holevo capacity: additivity implies tensorization of the Holevo barycenter, while tensorization alone is not sufficient for additivity. Although a construction is known that demonstrates the existence of channels with non-additive Holevo capacity, their corresponding Holevo barycenters still tensorize, leaving open whether multiplicativity might ultimately hold universally. Here, we answer this question in the negative by exhibiting channels for which the Holevo barycenter is not multiplicative under the tensor product of the channel with itself. Moreover, we show that the
entropy of the Holevo barycenter is neither universally subadditive nor universally superadditive under tensor product.
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All authors Sayantan Chakraborty, Stefano Mancini, Leonardo Rossetti, Andreas Winter
Quantum Physics
Materials for Quantum Information Science: Roles in the Quantum Evolution 2.0
Thang Pham, Vsevolod Ivanov, Dominic P. Goronzy et al. (+4 more)
Quantum information science is entering a second phase, the
Quantum Evolution 2.0, in which the challenge has shifted from demonstrating coherent control of individual
quantum states to building scalable multi-
qubit processors and networks. This transition places materials science at the center of the field. Across superconducting
circuits,
quantum defects,
quantum photonic devices, and emerging materials platforms, including two-dimensional materials and
heterostructures, performance is now limited less by device design than by poorly controlled surfaces, buried interfaces, and defects whose atomic identities remain incompletely known. This review surveys the materials challenges of these
quantum platforms together with the characterization methods needed to resolve them. For each platform we identify the dominant decoherence mechanisms, the current state of materials understanding, and the most pressing open materials problems. A cross-platform comparison then reveals a shared structure-coherence problem. The implicated material chemistry recurs across platforms, involving light elements in disordered or buried environments, yet no platform can quantitatively connect a specific atomic-scale structure to a measured change in coherence. We close by identifying three needs, mechanistic understanding of decoherence at the atomistic level, high-throughput proxy metrics predictive of device performance, and characterization tools built for
quantum materials, whose resolution would advance coherence, scalability, and integration across all platforms.
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All authors Thang Pham, Vsevolod Ivanov, Dominic P. Goronzy, Abhiram Devata, Joshua Feldon, David Barton, You Zhou
Classical Physics
Dunkl-Based Modeling of Vibrational Modes in Lightweight Elastic Beams
Hacene Bouguerne
Optimizing slender elastic structures for renewable energy applications requires non-classical continuum formulations capable of accounting for spatial micro-interactions without sacrificing analytical tractability. Here, we extend beam vibration mechanics by replacing standard spatial derivatives with the Dunkl differential operator. This modification introduces a reflection-coupled mathematical structure that accounts for spatial parity effects across the beam domain. We formulate the governing dynamic equations into a generalized
eigenvalue problem and derive exact analytical expressions for modal characteristics under standard boundary conditions. The classical limit confirms exact convergence to classical Euler-Bernoulli formulations. Parametric analyses reveal that the Dunkl parameter acts as a reflection-induced modulation parameter, significantly shifting natural frequencies and altering the modal characteristics of higher modes. These results provide an analytical baseline for dynamic optimization in lightweight structural components.
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Materials Science
Phase stability and mechanical response of Ag-interlayered Al/Cu resistance spot-welded joints
Shuang Lin, Kyubok Lee, Jiahui Ye et al. (+6 more)
Dissimilar Al/Cu joints are essential to battery-pack assemblies; however, their mechanical strength is limited by brittle Al-Cu intermetallic compounds (IMCs) such as Al2Cu and Al4Cu9. Interlayer strategies to suppress these phases remain largely empirical, lacking a predictive framework linking interlayer chemistry to the phases that form and to their intrinsic mechanical character. Here an Ag interlayer is introduced and combines computational thermodynamics, first-principles calculations, microstructural characterization, and mechanical testing into a single self-consistent description of the joint. CALculation of PHAse Diagrams (CALPHAD)
equilibrium and Scheil simulations predict the solidification path of the Al-rich Al-Ag fusion zone and explain why Cu incorporation is limited when Ag is present; energy-dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) confirm an FCC Al-Ag solid solution as the dominant constituent. First-principles
phonon calculations within the quasiharmonic approximation yield finite-temperature
entropy and Gibbs energy, benchmarked against CALPHAD, while elastic constants assess ductility via the Pugh criterion (i.e., the bulk/shear (B/G) modulus ratio). All Al-Ag phases, including the observed solid solution, exceed the Pugh threshold of 1.75, whereas the targeted Al-Cu IMCs do not, giving a mechanistic basis for the interlayer's effectiveness. This microstructural change translates into improved performance: nominal strength rises from 47.9 to 67.4 MPa. Nanoindentation gives a fusion-zone reduced modulus of 82.8 GPa (Young's modulus 82.0 GPa), versus a calculated 0 K Voigt-Reuss-Hill value of 71.4 GPa. The present work establishes a transferable CALPHAD, first-principles, and experiment workflow for rational interlayer selection in dissimilar-metal joining.
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All authors Shuang Lin, Kyubok Lee, Jiahui Ye, Ho Kwon, Shun-Li Shang, Allison M. Beesea, Xun Liu, Jingjing Li, Zi-Kui Liu
Adaptation and Self-Organizing Systems · Cross-listed from math.AP
Breathing and moving vesicles in a geometric mechanochemical model
Alexander Meiners and Hannes Uecker
We consider a
geometric mechanochemical model of vesicles which couples the Helfrich flow for the shape of a lipid
bilayer vesicle membrane $X$ with a reaction-
diffusion equations for a single “morphogen” $\phi$ on $X$. The Helfrich flow is the $L^2$ gradient flow of the elastic bending energy $E(X)=\int_X (H-c_0)^2 dS$ of $X$, typically supplemented by area or volume constraints, or both. The morphogen $\phi$ adsorbs/desorbs at places of high/low mean
curvature $H$, i.e., the kinetics of $\phi$ depend on $H$, and conversely $\phi$ modifies the spontaneous
curvature $c_0$ on $X$. The flow is no longer gradient, and hence allows for more complicated dynamics, including time periodic orbits, e.g., “breathing and moving” vesicle shapes. We show how to compute bifurcation diagrams for such solution branches via numerical continuation and bifurcation methods. We mostly focus on “planar” vesicles (1D closed curves) but also give an outlook on 3D vesicles (2D closed membranes).
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Quantum Physics
From the Unknown to the Desired: Transforming Unknown Initial States in the Resource Theory of Work and Heat
Tanmoy Biswas and Andreas Winter
We study thermodynamic state transformations in the resource theory of work and heat when the initial
quantum state is unknown. Moving beyond state-dependent protocols, we develop a universal framework in which a single transformation applies to all admissible input states. For mutually commuting conserved charges, we construct charge-conserving protocols whose transformation error, quantified by trace distance, decays super-polynomially with the number of system copies. As an application, we demonstrate universal work extraction: asymptotically optimal work can be extracted without microscopic knowledge of the initial state, with a super-polynomially small error. Our results show that thermodynamic state transformations remain achievable under limited prior information and establish a universal framework for resource-theoretic thermodynamics beyond the state-aware setting.
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Quantum Physics
Measuring the entanglement-breaking index of a qubit collision channel on a quantum processor: protocol and worked example
Eran Kopel
The
entanglement-breaking index of a
quantum channel is the smallest number of self-compositions after which the channel destroys all
entanglement with any reference system. A photonic experiment has fixed an index of 2; to our knowledge no larger index has been located by measuring the n-round channel across rounds. We give a protocol for doing so on a programmable processor, for any
qubit channel realised as a collision model whose ancillas are prepared in states diagonal in a known basis, so that the bath polarisation is set exactly by weighting basis-state configurations in the analysis. Single-
qubit process
tomography of the n-round channel gives the smallest
eigenvalue of its partially transposed Choi
matrix, read against zero at a pre-registered five standard deviations;
entanglement breaking survives further rounds, so the readings are monotone in n and the index follows. Comparing each direct measurement with the composition of the measured single-round map tests the repeated-interaction assumption. We show that a readable step needs margins on both sides, show how depolarising and reset errors move the readings, and give a power-based pilot rule. As a worked example we take one round of a three-
qubit feedback loop, compiled to eight CZ gates on a heavy-hex path with mid-
circuit reset, with certified ideal indices 3, 2 and 2 for three baths. The run is estimated to cost a few hundred seconds of processor time, and simulations under a device noise model, with the pilot's shot raise at low noise, recover all three indices.
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Superconductivity · Cross-listed from cs.CE
Fixed-mesh based approach for modeling of superconducting magnetic bearings
Elias Paakkunainen, Bárbara Maria Oliveira Santos, Gabriel dos Santos et al. (+3 more)
Numerical simulations of superconducting
magnetic bearings (SMBs) are complicated by the relative motion between high temperature
superconductors and the
magnetic guideway, which commonly requires repeated updates of the geometry and mesh. We present a fixed-mesh based approach for modeling the motion induced effects in which a coordinate transformation is applied only to the air region between the moving regions. The transformation can be included in a time-dependent anisotropic material tensor, leaving the mesh during the simulation and the rest of the formulation unchanged. To provide numerical examples, the approach is implemented in 2D using the finite element method with the $j$-$a$ formulation and is combined with homogenization and
circuit coupling for double-crossed loops of coated conductors. The open-source model implementations are made available. The proposed approach is verified and validated against existing modeling approaches and experimental results from the literature for SMBs. Two simulation examples are presented, and in both of them the levitation force predicted by the fixed-mesh model agrees with the experimental results, yielding $R^2$ values above 0.99. For a verification problem, it is shown that the fixed-mesh model converges towards the remeshed reference solution under mesh refinement as expected. For an SMB undergoing vertical and horizontal translations, the homogenized fixed-mesh model reproduces the lateral-force response of a fully resolved moving-geometry reference model. Additionally, the homogenized fixed-mesh model is computationally more efficient than the reference model, indicating a significant reduction in the number of degrees of freedom and the computation time. The results demonstrate accurate and computationally efficient simulation of translational motion with the fixed-mesh based approach.
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All authors Elias Paakkunainen, Bárbara Maria Oliveira Santos, Gabriel dos Santos, Timo Tarhasaari, Paavo Rasilo, Sebastian Schöps
Fluid Dynamics
Influence of wall thermal boundary condition on mean-flow characteristics of a Mach 2.5 fully rough turbulent boundary layer
Mateus A. R. Braga and Robyn L. Macdonald
We investigate turbulent boundary layers at Mach 2.5 over sinusoidal roughness at matched $Re_\tau=784$. We considered three wall temperatures, $T_w/T_r=$ 1.0, 0.7, and 0.4. Each wall temperature was repeated with a smooth and rough surface, the latter following a three-dimensional sinusoidal profile with effective slope 0.5 and matched $k^+=79.1$. In total six direct numerical simulations were completed. Analysis of mean wall shear and heat transfer detailed the augmentation in skin friction and heat transfer coefficient between smooth and rough cases; resulting in the classical failure of the Reynolds analogy for rough walls. We also show that differences in shear stress across wall temperatures are driven by the viscous component even though the pressure component dominates. The roughness sublayer was found to be $R_{RSL}=3k-6k$, consistent with the literature. Moreover, the wall offset $d=d_\Theta\approx0.5k$ for both momentum and thermal boundary layers, signifying the offset represents the half peak-to-valley height rather than the "mean roughness height." For the mean momentum boundary layer, we find the present conditions recover the incompressible roughness function $\Delta u_1^+$ when matched via the semi-local roughness Reynolds number $k^*$. For this reason, an equivalent sand-grain roughness of $k_s^*\approx3.7k^*$ is proposed. The existing compressible transformations hold regardless of wall temperature or roughness - contradicting recent claims otherwise. The generalized Reynolds analogy works for smooth walls but fails for rough walls; a roughness correction term is proposed and validated. Compressible mean temperature transformations fail for cold walls, especially when $(T_w-T_e)/(T_r-T_e)<0$. The thermal roughness function, $\Delta\Theta^+$, is reported with caution given transformation singularities.
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Cosmology and Nongalactic Astrophysics
A Finely-Binned Measurement of the Connected Even-Parity Galaxy 4-Point Correlation Function of DESI Year 1 Luminous Red Galaxies
William Ortolá Leonard, Alex Krolewski, Zachary Slepian et al. (+46 more)
We present the connected even-parity
galaxy 4-Point Correlation Function (4PCF) of DESI Year 1 (Y1) Luminous Red
Galaxies (LRGs). This is one of the first measurements of the connected 4PCF on data, and shows a clear detection at $\sim$12 to 17$\sigma$ in the full-sky analysis. We test the robustness of the signal by varying three factors: hemisphere (north vs. south),
redshift range (either the full range $0.4 < z < 1.1$ or the higher-number-density interval $0.4 < z < 0.8$), and sample completeness (the full sample vs. only the most complete regions within the number density-motivated cut). Finally, we cross-correlate different patches that are spatially well-separated, and thus should have largely independent noise. This approach, at leading order, is able to remove mismatch between the covariance
matrix of the data and that of the mocks; however, in certain cases at the cost of sensitivity. We find $\sim$15$\sigma$ evidence for an even-parity 4PCF in this approach. Overall, the studies of the 4PCF presented here probe sensitively any mismatch between mock catalogs and data, and also open up the prospect of fitting a model, constraining cosmological parameters and
galaxy biases, and searching for
Baryon Acoustic Oscillation (BAO) features.
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All authors William Ortolá Leonard, Alex Krolewski, Zachary Slepian, Alessandro Greco, Simon May, J. Aguilar, S. Ahlen, O. Alves, A. Aviles, F. Beutler, D. Bianchi, D. Brooks, A. Carnero Rosell, T. Claybaugh, A. de la Macorra, Biprateep Dey, S. Ferraro, J. E. Forero-Romero, E. Gaztañaga, Satya Gontcho A Gontcho, G. Gutierrez, K. Honscheid, D. Huterer, M. Ishak, S. Juneau, T. Karim, R. Kehoe, D. Kirkby, O. Lahav, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. A. Newman, E. Paillas, W. J. Percival, F. Prada, I. Pérez-Ràfols, C. Ravoux, R. Ruggeri, L. Samushia, E. Sanchez, C. Saulder, D. Schlegel, J. H. Silber, M. Siudek, G. Tarlé, B. A. Weaver
High Energy Physics (Phenomenology)
Constraints on Neutron-Electron Quantum Dark Forces
V. Kurmangaliyeva, B. Massak, O. Agyl-Mussapar et al. (+2 more)
Interactions induced by dark matter particles which couple bilinearly to standard model particles through
quantum fluctuations were termed
quantum dark forces by Brax, Fichet, and Pignol, who constrained the mass and couplings of dark scalar, dark vector, and dark
fermion bilinear exchange between nucleons. We extend their results to derive new constraints on
quantum dark forces from bilinear scalar exchange between
neutrons and electrons
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All authors V. Kurmangaliyeva, B. Massak, O. Agyl-Mussapar, S. Amangeldinova, W. M. Snow
Quantum Physics
Execution-transcript privacy for fault-tolerant surface-code memories
Jiachen Shen and Hui Zhong
A fault-tolerant
quantum computer runs behind a telemetry stream logging syndromes, decoder actions, resets and timing separately from the answer. Can it reveal the logical input? For a distance-$d$ rotated surface-code
memory on a fixed schedule of $T=\Theta(d)$ rounds, under three stated hypotheses (sector-scalar honest backbone, transcript locality, Kotecky-Preiss smallness), the channel from logical
qubit to transcript is $e^{-\Theta(d)}$-close in diamond norm to one that ignores the input. A statement of this kind follows generically from correctability-
privacy duality. Anisotropy does not. Each logical axis pays the distance of its own coset, so under amplitude damping the computational-basis label is governed by the code's $Z$-distance $d_Z\ge d_{\min}$ and not by the code distance. Two codes of
quantum distance $1$ make the gap concrete. A phase-flip code's $X$-syndrome transcript is exactly input-independent under unobserved damping, while a repetition code leaks at first order. A matched converse identifies the records that do expose it, among them a
lattice-surgery parity readout. On a 156-
qubit superconducting processor our sufficient certificate misses by $21.5\times$, so the
theorem cannot be invoked there. Measured directly, a $d_Z=1$
memory's record identifies its input with total variation $\ge 0.927$ under randomised, label-balanced acquisition. Holding the code fixed and varying the damping exposure reproduces the parameter-free law, with exponent $0.85\pm0.03$ against a predicted $0.86$. Randomized encoding returns the statistic to the floor at no two-
qubit-gate cost. Fault tolerance does not grant transcript
privacy. It relocates it, and only to the logical state, not to the
circuit's identity.
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Instrumentation and Methods for Astrophysics
The future of high-resolution UV spectroscopy: Science with a UV Échelle spectrograph on the Habitable Worlds Observatory, or a dedicated mission
Annalisa De Cia, David Cont, Kevin Heng et al. (+39 more)
High-resolution UV spectroscopy serves a diversity of science cases, from small bodies to
planets,
stars, and
galaxies, but is currently limited to the Hubble Space
Telescope and bright targets. Major advances require increasing sensitivity by at least one order of magnitude. Here we present the UV science cases for PEGASUS (
Planets, Earths,
Galaxies, And
Stars UV Spectrograph), a UV Échelle high-resolution spectrograph concept, with $R = \lambda/\delta\lambda \sim 100\,000$ (full range 10 000-140 000) and covering 90–400 nm, with a foreseen extension to at least 800 nm. PEGASUS is ideally suited for the Habitable Worlds Observatory (HWO), enabling transformative science across the UV/optical wavelength ranges. PEGASUS will be unique in high sensitivity (effective area) and high spectral resolution – an uncharted territory – as well as robustness, thanks to the simplicity of its design. Its UV science cases include: I) Formation and
evolution of
planets and their habitability: properties of
exoplanets and atmospheres, protoplanetary disks,
Solar System bodies; II)
Stellar lives and deaths at their extremes: the first
stars and the origin of the elements, compact and massive
stars,
Supernovae; III) Gas and metals in the
baryon cycle of
galaxies: the interstellar, circumgalactic, and intergalactic medium and their roles in
galaxy growth. These are essential for the Astro Decadal 2020 Survey, Voyage 2050, and HWO. While this paper focuses on high-impact science enabled by UV high-resolution spectroscopy, PEGASUS will extend into the optical regime and lower spectral resolution, making it a multi-purpose, widely used, workhorse spectrograph for HWO.
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All authors Annalisa De Cia, David Cont, Kevin Heng, Boris Gänsicke, Frank Grupp, Ralf Bender, Helena Lamprecht, Frances H. Cashman, Hsiao-Wen Chen, Valentina D'Odorico, Kevin France, Andrew Fox, Jens Hoeijmakers, Masahiro Ikoma, Wynn Jacobson-Galán, Sean D. Johnson, Mansi Kasliwal, Shingo Kameda, Varsha Kulkarni, Carlo F. Manara, Antonija Oklopčić, Cyrielle Opitom, Lidia Oskinova, Anna F. Pala, Ian U. Roederer, P. Christian Schneider, Peter Scicluna, Daniel E. Welty, Sascha Zeegers, Abel de Burgos Sierra, Miriam García, Avery Kim, Christina Konstantopoulou, Roberto Maiolino, Daniel Pauli, Tanita Ramburuth-Hurt, Philipp Richter, Andreas A.C. Sander, Tomer Shenar, Sergio Simón-Díaz, O. Grace Telford, Anna Velichko
Biological Physics
A thermodynamically consistent framework for finite growth of multi-constituent mixtures with application to tumor growth
Jonathan Stollberg, Marco F. P. ten Eikelder and Dominik Schillinger
Biological tissues grow by continuously producing, transporting, and reorganizing multiple interacting constituents. These processes are intrinsically coupled to finite deformation and residual stress. Existing models typically capture either finite growth kinematics or multi-constituent transport, but rarely both within a thermodynamically consistent setting. In particular, existing approaches do not consistently link the volume created by finite growth to the mass produced for each individual constituent. In this work, we develop a general continuum framework that unifies finite growth kinematics and multiphase mixture theory for fully saturated multi-constituent mixtures containing an arbitrary number of dilute dissolved solutes. Formulated in a solid-skeleton-based description, the framework rests on constituent-wise balance laws and a free-energy dissipation principle, from which thermodynamically admissible constitutive closures are derived for all mass-exchange, transport, reaction, and growth processes. The central novelty of the framework is a coupling between growth-induced volume creation and constituent mass production, expressed through volume accumulation fractions that distribute the newly created volume among the constituents while preserving saturation. We cast the resulting model in a total Lagrangian mixed weak form and specialize the general theory to a four-constituent, two-solute model of avascular tumor growth that couples nutrient transport, waste production, phenotype transitions between proliferative, hypoxic, and necrotic
cells, volume growth, elastic deformation, and growth-induced residual stress. The model is implemented within a finite element setting and its capabilities are demonstrated on representative
benchmark problems.
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Solar and Stellar Astrophysics
Chromospheric and Transition Region Responses of activities at the base of Coronal Plumes
Biswanath Malaker, Vishal Upendran and Durgesh Tripathi
We present the identification of the co-spatial and co-temporal small scale jets – sometimes also named as jetlets – at the base of the coronal hole plume associated with chromospheric and transition region (TR) flows. We identified 19 jets with coordinated observations recorded on March 19, 2016 using the
Solar Dynamics Observatory (SDO) and the Interface Region Imaging Spectrograph (IRIS). Our analysis of \ion{Si}{4} 1393.7~Å line suggests blueshifts mostly in the range of 10 to 33~km~s$^{-1}$, but few less than -10~km~s$^{-1}$, while analysis of co-spatial \ion{Mg}{2}~h~&~k lines show both blueshifts and
redshifts in the range of {–}9 to 17~km~s$^{-1}$. We observed highly asymmetric, enhanced intensity in \ion{Si}{4} line during these events. The upflows observed in transition region through \ion{Si}{4} is strongly correlated with chromospheric downflows observed in \ion{Mg}{2}. We interpret these results as a signature of interchange reconnections creating bi-directional flows – giving rise to upflows (downflows) in transition region (chromosphere).
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High Energy Astrophysical Phenomena
cuDART: a GPU-accelerated ray tracing code for generating synthetic observations of relativistic astrophysical sources
Henry Whitehead, Emma L. Elley and Christoper N. Everett
The generation of synthetic observations is required to compare simulations of astrophysical phenomena with real sources. We present a new open-source toolkit cuDART which allows meshed simulation data to be rapidly rendered into synthetic observations of optically thin emission, automatically accounting for a range of relativistic and
geometric effects such as Doppler boosting. Unlike previous visualisation schemes which generally consider a single snapshot in time, cuDART is capable of accounting for the finite time delay across astrophysical distances by rendering data from multiple simulation epochs simultaneously. We demonstrate how failing to account for a finite light time delay can result in synthetic observations with incorrect observed motion, morphologies and fluxes. The code does not require a static pattern frame for integration, relaxing standard assumptions required for analytical observational estimates. The rendering processes is accelerated through hardware (using GPUs) and software (using the 3D differential digital analyser
algorithm), allowing for rapid generation of observations from a large number of viewing orientations. In this paper we describe the physical motivation, document the code operation and test the output against theoretical relativistic and
geometric expectations. cuDART is publicly available via GitHub and documented using ReadTheDocs.
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