Quantum Physics
Mitigating quantum decoherence via global optimal control
Ashkan Abedi, Roberto Menta, Julien Despres et al. (+3 more)
We show that global optimal control can drastically suppress the impact of decoherence in globally driven superconducting
quantum computing architectures, taking as a prototype a recently proposed quasi-two-dimensional ladder geometry. Using a tensor-network-based approach, we quantify how amplitude-damping and dephasing channels degrade the flow of
quantum information along the ladder and the fidelity of one- and two-
qubit gate operations. We then demonstrate that shaping the global drive compresses the gate sequences by an order of magnitude in time, restoring high gate fidelities. We stress that this mitigation is far from trivial: in a globally driven processor, dissipation acts on every physical
qubit—including those outside the logical register that sustain the surrounding ordered phases—so its impact cannot be suppressed by protecting an isolated subsystem, and is instead overcome purely through the temporal shaping of the global drive.
Read the full abstract ▾
All authors Ashkan Abedi, Roberto Menta, Julien Despres, Marco Polini, Francesco Caravelli, Vittorio Giovannetti
Instrumentation and Detectors
Design and beam-test characterization of the CRILIN semi-homogeneous crystal calorimeter
S. Ceravolo, M. Cavallina, V. Ciccarella et al. (+17 more)
CRILIN is a high-granularity semi-homogeneous electromagnetic calorimeter based on longitudinally segmented PbF$_2$
crystal matrices read out by UV-extended silicon photomultipliers. The concept combines fast Cherenkov response, fine transverse granularity, longitudinal shower information, and radiation tolerance for future
lepton-
collider experiments. This paper reports the construction of a large-area prototype and its performance measured in beam tests at the CERN SPS. The detector comprises five $7\times7$ PbF$_2$
crystal matrices, has a depth of about $22X_0$, and is read out by four $3\times3~\mathrm{mm}^2$ SiPMs per
crystal integrated in a single electronic channel. Electron data between 10 and 120~GeV and dedicated 150~GeV
muon data were used to characterize the detector response. A time resolution below 50~ps is achieved for electron energies above 10~GeV, reaching values below 20~ps above 60~GeV. The energy resolution is described by a
stochastic term of $(6.58\pm0.04)\%/\sqrt{E/\mathrm{GeV}}$ and a constant term of $(0.23\pm0.02)\%$, with an additional noise contribution fixed from pedestal data. The longitudinal
segmentation enables event-by-event corrections based on the reconstructed shower development, resulting in a significant improvement of the energy resolution. A light yield of approximately 0.54~photoelectrons/MeV is measured consistently using both electron showers and minimum-ionizing particles. A Geant4-based simulation incorporating the relevant experimental effects reproduces the measured energy resolution. These results validate the CRILIN architecture as a compact, fast, and longitudinally segmented electromagnetic calorimeter for future
collider experiments.
Read the full abstract ▾
All authors S. Ceravolo, M. Cavallina, V. Ciccarella, E. Di Meco, E. Diociaiuti, R. Gargiulo, Q. Han, E. Leonardi, D. Lucchesi, M. Moulson, L. Palombini, N. Pastrone, I. Raghib, A. Russo, A. Saputi, I. Sarra, S. Salamino, L. Sestini, S. Squerzanti, D. Zuliani
Instrumentation and Methods for Astrophysics
DB-Bench: Benchmarking Deblenders for LSST DESC Using the Blending ToolKit
Aidan Berres, Grant Merz, Xin Liu et al. (+3 more)
Blending will be a major source of systematic uncertainty in downstream science analyses of LSST data. We
benchmark the performance of several deblenders, leveraging the Blending ToolKit (BTK) to perform rigorous, end-to-end testing. This
benchmark incorporates key deblending
algorithms, including SourceExtractor, SCARLET, and DeepDISC, with the goal of comparing their effectiveness in handling blended
galaxy images from LSST/Rubin simulations. A key focus is characterizing
algorithm performance in the regime of unrecognized blends, where multiple
galaxies are misidentified as a single object, as these cases introduce systematic biases that propagate into downstream cosmological analyses for
galaxy surveys. By utilizing BTK's ability to create customized, reproducible blends, we systematically test these deblenders against different blending conditions, such as source separation and brightness. The toolkit's standardized evaluation metrics, including detection precision,
segmentation accuracy, and source reconstruction, are comprehensive assessments of each
algorithm's strengths and limitations. Each deblender has performance caveats that may impact their true performance in real survey conditions. We find that SCARLET has high
segmentation and reconstruction performance, whereas DeepDISC has strong detection recall for faint and low-SNR sources, and SourceExtractor has accurate peak finding abilities but low
segmentation and reconstruction performance. This
benchmark provides valuable insights into the performance of existing deblenders and highlights areas for future development.
Read the full abstract ▾
All authors Aidan Berres, Grant Merz, Xin Liu, Éric Aubourg, Cécile Roucelle, the LSST Dark Energy Science Collaboration
Instrumentation and Methods for Astrophysics
Statistical treatment of searches for counterparts of positionally-uncertain astrophysical sources: from flux upper limits to detection
Julian Sitarek, Abelardo Moralejo, Juan Jiménez Quiles et al. (+3 more)
Rapid growth of the multimessenger and multiwavelength astrophysics had led to an increasing number of observations of the same events with instruments with different point spread functions. In particular pointing instruments with good angular resolution are used to pin-point the source of poorly-localized alert. In case no clear detection of the source counterpart is reached, the interpretation of the results requires statistical analysis. We investigate two approaches using the probability density function of the alert: frequentist and
Bayesian, as well as agnostic approach not using this information. We discuss the advantages and problems of all the methods, and compare their reliability and performance. We consider both a simple one-dimensional toy simulations and a realistic use case of full simulations of the follow-up of a gravitational wave event with gamma-ray
telescopes. The performance of both frequentist and
Bayesian approaches for weak signals is comparable and superior to the agnostic one.
Read the full abstract ▾
All authors Julian Sitarek, Abelardo Moralejo, Juan Jiménez Quiles, Giacomo D'Amico, Andrea Simongini, Antonio Stamerra
Strongly Correlated Electrons
From Exact Diagonalization to DMRG: A Complete Numerical Study of the Transverse-Field Ising Model
Chandra Sekhar Prayaga
We present a self-contained numerical study of the one-dimensional transverse-field Ising model (TFIM), tracing its ground-state
entanglement structure from exact diagonalization at small system size (L=8,14,20) through density-
matrix renormalization group (DMRG) calculations up to L=100. A single, consistent methodology - identical field grid, identical convergence diagnostic (independent runs at bond dimensions chi=100 and chi=200 at every point) - is used across all seven system sizes, and we show explicitly where exact diagonalization and DMRG must agree exactly rather than merely approximately. Along the way we document and resolve a bond-dimension convergence artifact that produced a spurious discontinuity in an earlier, less systematic
dataset, as a worked cautionary example for practitioners. Using the resolved
dataset we extract the central charge of the transition via two complementary routes - the leading logarithmic finite-size scaling of the mid-chain
entropy, and the full Calabrese-Cardy formula applied to every bond of every system size simultaneously - obtaining c_eff to 0.51-0.52 as short-distance
lattice corrections are systematically excluded, consistent with the exact two-dimensional Ising value c=1/2. We review the
quantum-classical (Suzuki-Trotter) correspondence that underlies this agreement and discuss how the Widom-Kadanoff scaling hypothesis transplants from the classical to the
quantum problem. The manuscript is intended as both a physics result and a worked methodological example of careful finite-size numerics.
Read the full abstract ▾
Atmospheric and Oceanic Physics
Memory compression and physical state augmentation favor different AMOC prediction tasks
Mauricio Herrera-Marín
The Atlantic Meridional Overturning Circulation is monitored and emulated through reduced indices, but such projections discard thermohaline structure and may require either explicit physical state or
memory of the observed index. We compare these strategies in 30 branch-consistent CMIP6 trajectories from eight model families using leave-one-family-out validation. Salinity, temperature and density information improves direct 20-year forecasts, whereas compact scalar
memory is top-ranked at every recursive horizon and yields the lowest case-averaged Brier score. A matched ablation confirms that feedback from
memory improves long-horizon prediction. Physical state and recent trends also predict future ocean-state changes beyond the emissions pathway, most robustly at five years. NorESM under SSP5–8.5 identifies a forcing-dependent limit of scalar compression, while MIROC shows negative long-horizon transfer. A resolvent analysis explains why stable
memory components do not guarantee stability of the complete learned model. Physical augmentation and
memory compression therefore serve different AMOC prediction tasks.
Read the full abstract ▾
Physics Education
Trajectories into Careers in the Quantum Industry: Beyond Knowledge and Skills
Shams El-Adawy, A.R. Piña, Benjamin M. Zwickl et al. (+1 more)
Career preparation for participation in the
quantum industry is often framed in terms of formal educational pipelines, workforce projections, and knowledge and skills needed for various roles. Less is known about how
quantum industry professionals themselves characterize their preparation for participation in the field. In this paper, we analyze interviews with
quantum industry professionals working across a range of positions and company types to examine the experiences that enable entry into the
quantum industry. Using thematic analysis, we identify four trajectories: (1) continuity of research practice from academia to industry, (2) reframing of prior expertise for
quantum applications, (3) incremental engagement through various professional opportunities, and (4) network-enabled entry. These trajectories often co-occur within individual narratives, showing that preparation emerges from a combination of educational, professional, and relational experiences. Our findings demonstrate that supporting preparation for
quantum industry careers requires more than the design of formal coursework and degree programs. Our results highlight the importance of experiential learning opportunities that allow students to apply their knowledge and skills and develop professional connections that facilitate entry into
quantum careers.
Read the full abstract ▾
All authors Shams El-Adawy, A.R. Piña, Benjamin M. Zwickl, H.J. Lewandowski
Computational Physics
Fast and Accurate Equivariant Foundation Models for Atomistic Simulation
Seán R. Kavanagh, Chuin Wei Tan, Menghang Wang et al. (+12 more)
Machine-learned interatomic potentials (MLIPs) have emerged as a transformative tool for computational materials science and chemistry, with universal potentials trained on large and diverse
datasets now routinely deployed as 'foundation models' for downstream fine-tuning in targeted chemical spaces. Many scientific applications of the resulting models, such as molecular dynamics (MD), require high inference and training speeds as well as accuracy. In this work, we examine the limits of equivariant MLIPs, which directly encode physical
symmetries in model architectures, to achieve these competing targets – particularly in the regime of extremely large
datasets where data efficiency is less critical. We show how this trade-off can be addressed, and present a family of foundation potentials in the NequIP and Allegro equivariant MLIP architectures which achieve leading inference speeds and strong scalability as well as excellent accuracies across a range of community
benchmarks – spanning materials discovery, thermal conductivity prediction, and near-
equilibrium mechanical and thermodynamic properties. Accelerations implemented within the NequIP infrastructure now permit training of high-accuracy foundation potentials on ultra-large
datasets with dramatically reduced computational cost. Alongside, we show that efforts to improve model accuracy for materials discovery should focus on
dataset diversity and improved, consistent descriptions of transition metal compound energy surfaces.
Read the full abstract ▾
All authors Seán R. Kavanagh, Chuin Wei Tan, Menghang Wang, Marc L. Descoteaux, Gabriel de Miranda Nascimento, Ulrik Unneberg, Laura Zichi, Francesco Libbi, Norma Rivano, Austin Glover, Vivek Bharadwaj, Anders Johansson, William C. Witt, Albert Musaelian, Boris Kozinsky
Strongly Correlated Electrons
Field-Selected Topological Buffering in a Disordered Skyrmion Crystal
Wenyu Su, Nvsen Ma, Chen Cheng et al. (+1 more)
Quenched disorder can disrupt crystalline order without immediately destroying the
topology of its constituent textures, but the relation between these processes in skyrmion
crystals remains unclear. Using large-scale simulations of a triangular-
lattice chiral magnet with random DM interactions, we show that the
magnetic field selects between two disordering routes. At high fields, global translational coherence is lost at a weak-disorder scale, while sixfold bond-orientational order survives to a larger disorder strength and the total topological charge remains nearly locked up to a substantially larger scale. The resulting interval defines a topological buffer containing a Bragg-glass- like skyrmion regime followed by a skyrmion-glass regime. Finite-size scaling, spatial correlations, defect statistics, and
spin autocorrelations support their distinct structural and glassy character. At lower fields, bond-orientational disordering nearly coincides with topological reconstruction, eliminating the skyrmion-glass window and contracting the buffer. These results identify the
magnetic field as a control knob for separating crystalline disordering from topological-charge loss and establish topological buffering as a mechanism by which topological textures can remain robust in structurally disordered media.
Read the full abstract ▾
All authors Wenyu Su, Nvsen Ma, Chen Cheng, Hong-Gang Luo
Mathematical Physics
Integrability in Asymptotic Symmetries of Spacetime: the $\text{BMS}_3$ scenario
Corentin Vitel
We discuss the existence of a well-defined $\mathfrak{bms}_3$-integrable hierarchy, introduced in Fuentealba et al. (JHEP, 2018), using different structural methodologies. Specifically, from the variational complex on the ring of
polynomial symbols, a $\mathfrak{bms}_3$ bi-
Hamiltonian structure is constructed on which a Nijenhuis operator can be attached. A similar argument is made for the $\mathrm{AdS}_3$ case, where we check that the flat limit of the latter recovers the asymptotically flat situation. An alternative $\tau$-scheme description is also presented. Moreover, a Lie-Poisson description suggests that such a $\mathfrak{bms}_3$-hierarchy is not unique. For a subclass of so-called energy-dependent Schrödinger operators, it is shown that their Lax flows are described by the coadjoint orbits of $\mathfrak{bms}_3$.
Read the full abstract ▾
Quantum Physics
Quantum Steering and Nonlocal Correlations Between Non-Interacting Delocalized Electrons Under Rashba Spin-Orbit Interaction
Zakaria Bouafia and Mostafa Mansour
We investigate
quantum steering and nonlocal correlations between two electrons in a two-dimensional electron gas (2DEG) as functions of Rashba
spin-orbit interaction (RSOI) strength and inter-electron separation. We focus particularly on the Bi/Ag(111) system characterized by its strong RSOI ($\alpha_0 = 3.05\times10^{-11}$ eV~m), and we explore the influence of tuning intensity of RSOI and inter-electron distance on the dynamics of Bell nonlocality, uncertainty-induced nonlocality and steering. We find that, although increasing $\alpha_R$ initially suppresses
quantum correlations, all three metrics exhibit a non-monotonic recovery as functions of $\alpha_R$, peaking near an optimal coupling strength $\alpha_R = 4.32\times10^{-11}$~eV~m across the range of inter-electron separations considered. This finding establishes RSOI as a critical control parameter for stabilizing
quantum properties in two-dimensional electron gases against the decay of
quantum correlations with inter-electron separation, and shows that the suppression and recovery of
quantum resources within the Bi/Ag(111) system can be controlled by adjusting the inter-electron distance and carefully tuning the RSOI strength.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Dynamics of compact binary systems in massive scalar Gauss-Bonnet gravity
Iris van Gemeren, Tanja Hinderer and Stefan Vandoren
Inspiraling binary systems of compact objects probe
gravity in strong-field regimes, thereby exploring potential higher
curvature corrections to General Relativity. Parity-invariant quadratic corrections can be described by scalar-Gauss-Bonnet (sGB) theory, which involves a scalar field dynamically coupled to
curvature scalars and can give rise to scalar condensates around black holes. Considering a mass for the scalar field is natural and leads to new phenomenology related to this additional scale. We compute the dynamics of a binary system of nonspinning black holes in massive sGB using the post-Newtonian (PN) approximation. We obtain solutions for the equations of motion, center-of-mass transformation, and binding energy for circular and eccentric orbits up to 1PN order, where for the first time the higher
curvature coupled to scalar mass corrections are included. While most of our calculations are valid for generic scalar masses, the final explicit expressions assume that the mass is small compared to the total mass of the binary and expand to quadratic order in this ratio. We show that the scalar mass corrections to the gauge-invariant binding energy come with same and opposite sign order terms, contributing an overall opposite sign contribution in the perturbative limit, decreasing the binding energy slightly. The effects are largest for binary systems with high mass ratio and large eccentricity. Our methods and results will also be useful as a basis for computing the gravitational waves sourced by such systems.
Read the full abstract ▾
Solar and Stellar Astrophysics
Magnetic Reconnection Process in Partially Ionized Fluids: Insights from the Solar Chromosphere
Adrian R. Montañez-Lobo and Fabio D. Lora-Clavijo
Magnetic reconnection converts stored
magnetic energy into kinetic energy, heat, and radiation. While extensively studied in fully ionized
plasmas, observations show that ionization and recombination also play a role by modifying the local
plasma resistivity and enabling additional heating channels. This study examines
magnetic reconnection in the partially ionized
solar chromosphere, analyzing its morphology and energy releases with
attention to elastic collisions, ionization, and recombination. The MAGNUS code, originally built for ohmic resistivity and heat transfer, was modified to handle elastic and inelastic collisions. The simulations are 2.5D resistive MHD with two-fluid effects (charged + neutrals), adapted to handle interactions via these collision terms. A mixed explicit-implicit scheme was implemented to manage the stiffness of these terms. Simulations were carried out for three
magnetic field strengths: 100~G, 110~G, and 120~G. These values correspond to the low- to mid-chromosphere under quiet-Sun conditions. We found that reconnection heats the
plasma components by 18% to 110%. Although
plasma beta rises only slightly, the energy release grows far more, indicating that charged–neutral collisions, not just beta or available
magnetic energy, drive the enhanced reconnection. Furthermore, ionization and recombination become most significant in regions of peak temperature, particularly where particles are accelerated. Maximum reconnection rates from temporal analysis are 0.226, 0.253, and 0.279, respectively. Finally, in terms of energy, our results show that in a chromospheric volume of $0.4 \times 0.01 \times 0.4$~Mm$^{3}$, the energy released ranges from $10^{22}$ to $10^{23}$.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Inflation, Open Universes, and Dark Energy
Anton Chudaykin, Mikhail M. Ivanov, Renata Kallosh et al. (+3 more)
We study the impact of spatial
curvature ($\Omega_k$) and dynamical dark energy (parametrized by $w_0$ and $w_a$) on the spectral index $n_s$ using a combination of
cosmic microwave background
datasets (Planck, SPT, and ACT), and spectroscopic
galaxy samples from DESI, including both BAO and full-shape clustering measurements. We show that a small negative
curvature, $\Omega_k\simeq 3\times 10^{-3}$, lowers the value of $n_s$, bringing it closer to predictions of the Starobinsky,
Higgs, and simplest $\alpha$-attractor inflationary models. In particular, we find $n_s= 0.9667\pm0.0041$ (using Planck and DESI data) or $n_s= 0.9692\pm0.0035$ (adding ACT and SPT). Allowing for time-evolving dark energy also reduces the spectral index, leading to $n_s=0.9716\pm0.0032$ (from the combined
dataset), or $n_s=0.9694\pm0.0035$ in combination with a small negative
curvature. Our results demonstrate that the tension between current observational data and the Starobinsky,
Higgs, and simplest $\alpha$-attractor models holds only for $\Lambda$CDM, and can be mitigated in extended cosmological models. We discuss implications of these findings for inflationary models in an open universe and/or with dynamical dark energy, including scenarios with
quantum tunneling and non-standard
topology. Furthermore, we briefly describe a special class of $\alpha$-attractor models, where one can make $n_s$ arbitrarily large, and we describe the $\alpha$-attractor quintessence model. Such models may be of particular relevance when future data from DESI, as well as DESI-II, SPHEREx, Euclid, Rubin, and Roman, becomes available.
Read the full abstract ▾
All authors Anton Chudaykin, Mikhail M. Ivanov, Renata Kallosh, Andrei Linde, Oliver H. E. Philcox, Yusuke Yamada
Lattice Field Theory
On credit attribution and research software: A case study from lattice QCD
Alessandro Sciarra
Questions of authorship, credit attribution, and the recognition of research software contributions have become increasingly prominent in continually expanding research areas in which software constitutes an essential part of the research process. While general guidelines and best practices exist, their application in concrete situations often raises nontrivial interpretative and procedural issues. This article presents a documented case study from
lattice QCD research in which the author was directly involved, illustrating how the development of numerical strategies, long-term software infrastructure, and conceptual extensions of existing work can give rise to complex questions of authorship, priority, and credit attribution. Rather than discussing the underlying scientific results, the focus is on the sequence of events, the role of software as long-term research infrastructure, and the interaction with established mechanisms for credit attribution and research integrity assessment. The aim of this work is to contribute to transparency and discussion on how current practices and guidelines are applied in realistic collaborative environments, and to highlight structural tensions that may arise between open scientific collaboration, software sustainability, and traditional notions of authorship. The article is intended as a factual account and reflection on research practice, and aims to stimulate discussion on whether additional community standards for recognising long-term research software contributions may be beneficial within
lattice QCD.
Read the full abstract ▾
Materials Science
Transport Evidence of Magnetic Polarization in the Altermagnetic Candidate MnTe
Younes Ghorbani, Nayana Devaraj, Joshua Maile et al. (+7 more)
The ability to precisely control
magnetic properties is central to the development of future
spin-based electronics. In this work, we report the successful growth of epitaxial {\alpha}-MnTe thin films on InP(111) substrates using molecular beam epitaxy. Magneto-transport measurements at low temperatures reveal a distinct, hysteretic butterfly longitudinal magnetoresistance alongside a nonlinear transverse magneto-resistance response, suggesting the presence of a finite net
magnetic polarization in the films. To understand the origin of this behavior, density functional theory (DFT) calculations were performed. While pristine bulk MnTe is a compensated antiferromagnet, our computational results suggest multiple pathways through which a finite magnetization can emerge in thin-film geometries, including interface-induced
symmetry breaking and point defects. These findings demonstrate an epitaxial route for engineering
magnetic responses in thin films.
Read the full abstract ▾
All authors Younes Ghorbani, Nayana Devaraj, Joshua Maile, Samuel Poage, Qihua Zhang, Maria Hilse, Stephanie Law, Salva Salmani-Rezaie, Awadhesh Narayan, Kaveh Ahadi
High Energy Astrophysical Phenomena
Binary neutron stars in the next-generation era: Multi-messenger detection prospects and constraints on the equation of state, mass distribution, and cosmology
Hauke Koehn, Thibeau Wouters, Gilad Sadeh et al. (+5 more)
Next-generation gravitational-wave (GW) observatories will provide crucial insights into the nature of
neutron star (NS) matter and the cosmological expansion history. We estimate the number of multi-messenger detections from binary
neutron stars (BNS) with the Einstein
Telescope (ET) and
Cosmic Explorer (CE), and project the resulting constraints on the equation of state (EOS), BNS mass distribution, and cosmology via joint hierarchical
Bayesian inference. Assuming a local merger rate of 106.6 Gpc$^{-3}$ yr$^{-1}$ and considering two different mass functions, a narrow one centred around 1.4 $M_\odot$ and a wide one ranging between 1.1–2 $M_\odot$, we find that for ET, our mock follow-up
algorithm results in at least $\sim40$ and up to $\sim100$ successfully identified electromagnetic counterparts per year, depending on the detector layout and mass distribution. In a joint network with CE, the number of multi-messenger detections can range from $\sim 200$ to $\sim500$. Additionally, several more afterglows from gamma-ray bursts or KNe could be found with dedicated late-time observations. Based on the identified multi-messenger events, we perform an injection campaign to hierarchically constrain the EOS, mass distribution, and cosmology in a fully
Bayesian framework. Focussing on ET alone, we show how in an ideal scenario, GW signals, KNe, and host
galaxy redshifts can constrain the canonical NS radius $R_{1.4}$ within $\sim 0.2$ km and the Hubble constant $H_0$ within $\sim 1$ km s$^{-1}$ Mpc$^{-1}$, while recovering the essential features of the mass distribution. By comparing inference results that rely solely on GW data and those that incorporate light curve information, we find that while KN light-curve posteriors have a negligible impact on the EOS constraints, they can benefit the inference of cosmological parameters.
Read the full abstract ▾
All authors Hauke Koehn, Thibeau Wouters, Gilad Sadeh, Peter T.H. Pang, Mattia Bulla, Chris Van Den Broeck, Michael W. Coughlin, Tim Dietrich
Quantum Physics
Classical Tensor Network and Quantum Fourier Transform Approaches for Large-Scale Carr-Madan Option Pricing
Sascha Hauck and Ivica Turkalj
Fourier-based methods are among the most widely used techniques for pricing European options when the characteristic function of the underlying asset process is available. Their applicability to increasingly fine discretizations, however, is limited by the rapidly growing
memory requirements of classical
Fourier transforms, which become a computational bottleneck for large-scale pricing problems. In this work, we overcome this limitation by reformulating the Carr-Madan pricing framework using tensor networks. Specifically, we employ the Superfast
Fourier Transform (SFFT), a compressed Tensor Train representation of the
Quantum Fourier Transform (QFT), and apply it directly to tensorized option pricing without ever explicitly constructing exponentially large vectors or
Fourier operators. This formulation also enables a direct comparison between the classical tensor network
algorithm and its
quantum counterpart through QFT-based option pricing on
quantum simulators and
quantum hardware. Numerical experiments for European call options demonstrate that the proposed SFFT method maintains pricing accuracy while substantially reducing
memory requirements and achieving subexponential computational scaling compared with conventional FFT-based pricing. The accompanying
quantum simulations and hardware executions enable a direct comparison between the classical tensor network formulation and its QFT-based
quantum counterpart, showing that both approaches avoid the exponential scaling of conventional
Fourier implementations and provide complementary perspectives on large-scale option pricing. Together, these results establish a unified framework connecting classical
Fourier pricing, tensor network
algorithms, and
quantum computing approaches, demonstrating how tensorized
Fourier methods can provide scalable alternatives for high-dimensional financial computations.
Read the full abstract ▾
Materials Science
Hydration-Controlled Layer Stacking in (NH$_3$)$_2$Cu$_5$(SeO$_3$)$_2$(OH)$_6$(H$_2$O)$_{2+x}$ ($x$ = 0, 1, and 3)
Priya R. Baral, Christian Jandl, Pauline Pradal et al. (+3 more)
Hydration and dehydration are powerful yet underexplored variables for controlling the architecture of layered inorganic materials, because intercalated water can modify interlayer separation, hydrogen-bonding networks, and layer stacking. Here, we report the reflux synthesis of a new family of hydrated layered copper selenites, (NH$_3$)$_2$Cu$_5$(SeO$_3$)$_2$(OH)$_6$(H$_2$O)$_{2+x}$ ($x$ = 0, 1, and 3). From the
crystal structures determined using electron diffraction and single
crystal X-ray diffraction, we deduce that all three compounds share an identical layer built from Cu(OH)$_4$ squares and Cu-centered square pyramids forming distorted kagomé-like Cu$^{2+}$ network. While the intralayer atomic arrangement is preserved across the series, the degree of hydration governs both the interlayer separation and the stacking sequence. These compounds therefore provide a rare platform relevant to the design of hydration-responsive materials for sensing, ion transport, separations, actuation, and energy-related applications. The preservation of distorted kagomé-like Cu$^{2+}$ layers across hydration states further suggests potential interest for examining how interlayer water and stacking sequence affect low-dimensional
magnetic coupling. Under reflux conditions, these phases are also shown to act as reactive intermediates in the formation of Cu$_2$OSeO$_3$, establishing them as tunable precursors for copper oxoselenite synthesis.
Read the full abstract ▾
All authors Priya R. Baral, Christian Jandl, Pauline Pradal, Johann Roos, Wenhua Bi, Arnaud Magrez
Quantum Physics
Improved Convergence of Carleman-Embedded Quantum Algorithm for the Vlasov-Poisson System
Matthew Christensen, Tom Goffrey and Animesh Datta
We extend the regime of convergence of Carleman-embedded
quantum algorithms that solve the Vlasov-Poisson equations from kinetic
plasma physics. We establish convergence, using both analytical and numerical lower bounds, for physically reasonable collision frequencies using a
Fourier-Hermite expansion of the shifted phase-space distribution function. We also show that for a large class of basis functions, the convergence of the Carleman-embedded Vlasov-Poisson system requires increasing collision frequency strength with velocity resolution. The complexity of the
quantum algorithm depends strongly on whether we seek time-averaged or -resolved outputs.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Anomalous metal and superconducting phases in rhombohedral graphene
Anna Okounkova, Abigail Sohm, Tobias Faehndrich et al. (+7 more)
Two-dimensional superconductivity is now well established in
graphene-based systems, with many such realizations showing evidence for unconventional pairing. Yet in several of the gate-tuned phases that otherwise exhibit clear signatures of superconductivity, the resistance does not vanish as temperature is lowered, instead saturating at a finite value. Here we report a systematic study of this behavior in rhombohedral
graphene on a WSe$_2$ substrate, finding regions of gate space with zero-resistance superconductivity alongside others with finite saturation resistance. At zero
magnetic field, these regions appear as isolated pockets in gate space that otherwise exhibit strikingly similar phenomenology, including abrupt transitions to the normal state as temperature, perpendicular
magnetic field, and current are raised above critical values. A small in-plane field expands and merges these pockets without qualitatively altering their behavior, producing a sharp boundary at millikelvin base temperature between states of zero or finite resistance. The finite-resistance state reproduces key phenomenology associated with the anomalous metal, a state that has been observed in thin-film
superconductors for decades but lacks an accepted theoretical explanation. The tunability and reproducibility of ultra-clean rhombohedral
graphene place strong constraints on extrinsic explanations and provide a new platform for understanding this behavior.
Read the full abstract ▾
All authors Anna Okounkova, Abigail Sohm, Tobias Faehndrich, Manish Kumar, Derek Waleffe, Jiaqiang Yan, Kenji Watanabe, Takashi Taniguchi, Joshua Folk, Matthew Yankowitz
Quantum Physics · Cross-listed from cs.LG
QAdapt: Noise-Adaptive Neural Pre-Decoding for Surface-Code Quantum Error Correction
Ran Miao, Rui Luo, Xiaohan Shan et al. (+1 more)
Fault-tolerant
quantum computing relies on
quantum error correction to protect logical information, requiring classical decoders that keep pace with syndrome generation. Heterogeneous, changing hardware noise and the distribution shift from simulation to experiment challenge the accuracy and robustness of fixed neural decoders. We present QAdapt, a noise-adaptive neural pre-decoding framework for surface-code
quantum error correction. QAdapt learns local spatiotemporal correlations, continually adapts across noise environments, and passes the residual syndrome to a conventional global decoder. Online elastic weight consolidation limits forgetting as training moves between measurement, idle, CNOT, and Pauli-bias noise regimes. At distance nine, the HTNet pre-decoder reduces equivalent per-round logical error by 15.64% relative to Ising-Fast, with 28.75% fewer parameters and 9.07% less matching-backend time. Online EWC reduces average forgetting by 76.52% relative to sequential fine-tuning. With weights frozen, it reduces equivalent per-round logical error by 5.66% relative to continued base-environment training on a fixed valid domain of 331 unseen compound-noise conditions; whole-sequence failure probability falls by 2.54% over all 396 conditions. On native Willow records, the corresponding per-round reductions are 19.44%, 17.47%, and 17.95% at 10, 30, and 50 rounds, without target-domain fine-tuning. These results show how adaptive neural pre-decoding can improve logical accuracy, preserve performance across noise regimes, and reduce residual matching workload within an established decoding pipeline.
Read the full abstract ▾
All authors Ran Miao, Rui Luo, Xiaohan Shan, Xiaoming Sun
High Energy Physics (Theory)
Covariant variation and its applications
Wen-Bin Liu and Jiang Long
We define a covariant variation of tensor fields by combining its Lie derivative with the metric variation. This operator preserves the metric, contractions, and Hodge duality, but its commutator is not closed due to an anomaly. We derive its algebraic and
geometric properties, and compare it with the Kosmann derivative. Combining the covariant variation with Kosmann derivative gives total covariant variation for the fields with both spacetime and Lorentz structure, all of which belong to the metric Lie derivative. Moreover, we introduce families of extended operators which contain the affine connection, Lie derivative, and covariant variation. From the anomaly of the covariant variation along the superrotation, an electromagnetic helicity flux appears at null hypersurfaces in four dimensions. We also apply the covariant variation and its anomaly to tensor fields in arbitrary spacetime dimensions, and especially focus on the $p$-forms in $d=2p+2$ dimensions.
Read the full abstract ▾
Statistical Mechanics
Convergence to the exact kinetics of the one-dimensional Riviera model
Pascal Viot
The Riviera model is a random sequential deposition model for house building on a
lattice, in which a house cannot be built when both nearest-neighbor sites are already occupied. In one dimension, an attempted deposition is therefore rejected whenever the target site is an isolated vacancy. Despite the apparent simplicity of this rule, no exact analytical solution of the original model is currently known. We derive an infinite hierarchy of kinetic equations governing its dynamics and introduce a systematic closure scheme that can be implemented at arbitrary finite order. Solving the resulting systems order by order, we show that the corresponding kinetics converges rapidly toward the exact behavior. At high order, the method yields an exceptionally accurate estimate of the jamming density while retaining explicit analytical expressions for the full time-dependent
evolution.
Read the full abstract ▾
Materials Science
Quasiparticle phono-conversion: filming carriers coalescing into excitons
Enrico Perfetto, Takumi Fukuda, Xing Zhu et al. (+12 more)
Condensed matter physics is replete with phenomena involving high-energy free particles coalescing into low-energy bound few-particle states. While the cooling of the individual particles is well understood, the crucial step by which cold free carriers form a bound state remains elusive, involving complex energy and momentum relaxation pathways. Here, by combining ultrafast time- and momentum-resolved photoemission spectroscopy on a monolayer WSe$_2$ with the first-principles excitonic-Bloch equations, we resolve the conversion of initially free electrons and holes at the bandedges into bound
excitons. With unprecedented energy resolution, we observe the transient coexistence of free-carrier and excitonic bands, accompanied by a transfer of spectral weight between the two. We establish the phononic origin of
exciton formation and ascribe this coexistence to a sequential relaxation cascade toward the lowest-energy excitonic states, wherein intermediate states remain weakly populated. The efficiency of this process is controlled by valley multiplicity, large-momentum
phonon emission and
spin-flip processes. By elucidating how bound states emerge from their elementary constituents, our results point to strategies for engineering
exciton formation, with direct implications for optical materials and devices that operate with
excitons or free carriers.
Read the full abstract ▾
All authors Enrico Perfetto, Takumi Fukuda, Xing Zhu, Jacques Hawecker, Harley Suchiang, Joanna Nadolna, Nanami Tomoda, Suji Park, Houk Jang, Kenji Watanabe, Takashi Taniguchi, Michael K. L. Man, Julien Madéo, Keshav M. Dani, Gianluca Stefanucci
Medical Physics
A reduced viscoelastic FDTD formulation for ultrasound-driven shear wave propagation in soft tissue
Gianmarco Pinton
Ultrasound-driven shear wave propagation in soft tissue underlies shear wave elastography (SWE) and emerging elastomechanical hypotheses of ultrasonic neuromodulation, both of which require accurate, efficient modeling of radiation-force–induced tissue motion. General-purpose finite-element elastodynamic solvers are often computationally expensive and unnecessarily broad for shear-dominant applications. We derive a reduced viscoelastic formulation by applying near-incompressibility, small-strain linearization, Helmholtz decomposition, and solenoidal force projection to the full Navier equations, yielding a Kelvin–Voigt shear wave equation that retains only the transverse dynamics relevant to radiation-force–induced motion. An explicit finite-difference time-domain (FDTD) implementation with second-order spatial and temporal accuracy enforces the solenoidal body-force constraint via a
matrix-free conjugate-gradient Poisson solve. For separable radiation-force sources, a pre-computed projection reduces this cost by one to two orders of magnitude. In homogeneous media the solver recovers the theoretical shear wavespeed to within $<$0.1%, exhibits clear second-order grid convergence (trace-$L_2$ self-convergence, $p\gtrsim2$), and matches analytical Kelvin–Voigt attenuation and phase speed to within ${\sim}3\%$ and $<$1% over a 16-point viscosity sweep ($\eta\in[0,1.5]$~Pa$\cdot$s). An end-to-end RSNA QIBA phantom
benchmark recovers shear wave speeds to within ${\sim}1\%$ across a tenfold shear-modulus range ($G=1$–$10$~kPa). The framework accommodates spatial heterogeneity in shear modulus, density, and viscosity, and integrates with acoustic simulators. Transcranial demonstrations through micro-CT skull geometries produce shear displacements of 1.7–5~$\mu$m consistent with clinical ARFI.
Read the full abstract ▾
General Relativity and Quantum Cosmology
The BGV Theorem and the Null Convergence Condition
William H. Kinney
We examine the relationship between the Null Convergence Condition (NCC) and the Borde-Guth-Vilenkin (BGV)
Theorem. We first show that, for an expanding spacetime foliated orthogonally to a timelike geodesic congruence with vanishing shear and vorticity, the BGV
Theorem follows when the NCC holds and the spatial
curvature is non-positive, ${}^3\mathcal{R} \leq 0$. The situation becomes more complex in the presence of shear, or non-geodesic threading of the spacetime. In these cases, the local expansion that enters the BGV construction depends not only on the local scalar expansion, but acquires terms given by the contraction of the shear and acceleration with locally defined spatial unit vectors. In the general case, null convergence and non-positive
curvature are no longer sufficient to guarantee that the BGV
Theorem holds. We discuss the result in the context of eternal inflation in the presence of comoving
curvature perturbations and state a more general version of the BGV condition relevant to asymptotically past-de Sitter eternal inflation.
Read the full abstract ▾
Quantum Physics
Nearly optimal quantum circuits for Boolean oracles
Junhong Nie and Wei Zi
Quantum oracle of Boolean functions is one of the central bridges between classical and
quantum algorithms, but the study focusing at
quantum circuit optimization of such oracle is yet closed. In this paper, we propose nearly optimal tradeoffs among
circuit size,
circuit depth and ancilla count, for
quantum oracles of three kinds of Boolean functions: general total Boolean functions with output size $b$: with $1\le m\le\Theta\left(\frac{2^n}{n}\right)$ ancilla, size $\mathcal{O}\left(\frac{b2^n}{\log(n+m)}\right)$, depth $\mathcal{O}\left(\frac{b2^n}{n+m}\right)$; partial Boolean functions of effective support size $d$ and output size $b$: with $\Theta\left(\log d\right)\le m\le \Theta\left(d\right)$ ancilla, size $\mathcal{O}\left(n\log d+bd\right)$, depth $\mathcal{O}\left(\frac{n\log n\log d}{n+m}+\log n+\frac{d(\log d+b\log m)}{m}\right)$; sparse Boolean functions of true input size $d$: with $\Theta\left(\log n+\log d\right)\le m\le\Theta\left(\frac{nd}{\log d}\right)$ ancilla, size $\mathcal{O}\left(n^2\log d+\frac{nd}{\log(\log d+m/n)}\right)$, depth $\mathcal{O}\left(\frac{n^2\log n\log d}{n+m}+\log n+\frac{nd}{m}\right)$. All the size and depth bounds are asymptotically optimal up to logarithmic factors in the corresponding ancilla count regions. We hope these results find applications in scenarios where classical procedures are needed to be embedded into
quantum circuits, such as QROM implementation and
quantum algorithm design.
Read the full abstract ▾
High Energy Physics (Theory)
Missing Descendants in the Carrollian Conformal Family
Yu-fan Zheng
In the Carrollian conformal
algebra, the relation $[P^0,K^0]=0$ implies that $K^0$ annihilates all operators generated from a primary by temporal translation $P^0$. The standard conformal family defined by translation descendants does not contain the independent descendant chain that $K^0$ lowers successively to the primary. We construct the complete Carrollian conformal representation by including this chain together with all of its translation descendants. We derived the corresponding local operators, orbit structures, and checked their Casimirs in 2D and 3D. For each orbit configuration, the global two-point Ward identities fix the kinematic factors and selection rules for both
magnetic non-contact branches and electric contact branches. Unlike ordinary conformal
symmetry, Carrollian conformal
symmetry generally determines the correlators only up to arbitrary functions of Carrollian invariants rather than constants. The complete representation contains sectors with $\mathcal{C}_2=m^2=\kappa\rho-\beta^2>0$ for 2D and $\mathcal{C}_2=m^2=\kappa\rho-\vec{\beta}^{\,2}>0$ for 3D, which may describe massive states in flat holography.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Estimating amplitude of matter density fluctuations in solar and supernova models using neutrino flavor evolution
Caroline Laber-Smith, Hansen Torres, Lily Newkirk et al. (+3 more)
Neutrinos can undergo substantial
flavor evolution between their production in astrophysical sources-such as the Sun and core-collapse
supernovae-and their subsequent detection in terrestrial detectors. This
flavor evolution is strongly influenced by the environment that the
neutrinos interact with, making them useful astrophysical messengers capable of potentially carrying information about the properties of the source wherein they are produced. In this work, we apply the framework of statistical data assimilation (SDA) in order to ascertain the extent to which a
neutrino signal at detection may contain information about matter density fluctuations along their path from the source. Using simplified models of
neutrino flavor evolution and propagation in the sun and in a core-collapse
supernova (CCSN), we find that the SDA method is able to extract information about the amplitude of density fluctuations in both the
solar and CCSN scenarios, with the method showing relatively greater reliability in the
solar neutrino case. Nonetheless, even in the CCSN
neutrino model, the method proved effective at high fluctuation amplitudes
Read the full abstract ▾
All authors Caroline Laber-Smith, Hansen Torres, Lily Newkirk, Dhriti Rathod, A. Baha Balantekin, Amol V. Patwardhan