Peer Revenue Impact factor: volatile

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics Physics

physics Watch Physics

Tuesday 7 October

General Physics

Holographic connection of f(G) gravity through Barrow and a generalized version of holographic dark fluid

Surajit Chattopadhyay

In the context of f(G) modified gravity, we address the cosmic application of the most generalized form of holographic dark energy (The European Physical Journal C, 77, (2017): 1-8) in this study, as well as a specific instance of it in the form of Barrow holographic dark energy (Physical Review D, 102(12), p.123525). Holographic dark energy and a well-known power law form of the scale factor a(t) are added to the f(G) model in order to achieve this. It is observed that a sufficient criterion for a realistic modified gravity model is satisfied by the reconstructed f(G). The reconstruction models are also tested under the four energy situations.
Read the full abstract

Instrumentation and Detectors

Long wave infrared detection using probabilistic spintronic bolometer arrays

Utkarsh Singh, Leif Bauer, Angshuman Deka et al. (+5 more)

The use of probabilistic spintronic devices for infrared radiation detection has introduced a shift in approach to thermal imaging. The integration of probabilistic magnetic tunnel junctions with infrared plasmonic nano-antennas achieves high-sensitivity digital-mode infrared sensors at room temperature. Here, we present a scalable approach towards multipixel plasmonic-spintronic bolometer array fabrication and readout. We fabricate proof-of-concept 2x2 row-column multiplexed probabilistic plasmonic sprintronic arrays and show their response to long-wave infrared radiation (8-14um) with high readout speeds (10K-1M counts per second). These spintronic, ultrafast, nanoscale (SUN) bolometers can result in novel high-pixel density CMOS compatible infrared detection platforms. Our work provides a broadband (9kHz to 3GHz) readout platform for future digital probabilistic detector applications. Furthermore, our approach addresses a key challenge associated with scaling infrared pixel sizes that can drive progress towards high pixel density detector arrays for infrared sensing and microscopy applications.
Read the full abstract

All authors Utkarsh Singh, Leif Bauer, Angshuman Deka, Mohamed Mousa, Daien He, Sakshi Gupta, Bhagwati Prasad, Zubin Jacob

Space Physics

Influence of Solar Sails on Magnetic Field Measurements in Space Plasmas

Konstantinos Horaites, Juan V. Rodriguez and Ying Liu

Solar sail technology is ready to be deployed in a satellite mission carrying a science-grade magnetometer. In preparation for such a mission, it is essential to characterize the interactions between the sail and the ambient plasma that could affect the magnetometer readings. The solar wind magnetic field is a key parameter in space weather prediction, because it governs the energy-releasing magnetic reconnection process at Earth's magnetopause. This paper investigates the influence of solar sails on the ambient magnetic field, particularly focusing on two critical electromagnetic effects: eddy currents and magnetic pileup. We find the induced eddy currents in the metallic sail can significantly perturb the local magnetic field at high frequencies. We also suggest that magnetic pileup can influence the spacecraft's environment when the sail size is comparable to the electron kinetic scales of the surrounding plasma. This research provides an initial guide for determining when sail-plasma interactions could impact magnetometer performance.
Read the full abstract

Instrumentation and Detectors

Study of few-electron backgrounds in the LUX-ZEPLIN detector

D.S. Akerib, A.K. Al Musalhi, F. Alder et al. (+204 more)

The LUX-ZEPLIN (LZ) experiment aims to detect rare interactions between dark matter particles and xenon. Although the detector is designed to be the most sensitive to GeV/$c^2$–TeV/$c^2$ Weakly Interacting Massive Particles (WIMPs), it is also capable of measuring low-energy ionization signals down to a single electron that may be produced by scatters of sub-GeV/$c^2$ dark matter. The major challenge in exploiting this sensitivity is to understand and suppress the ionization background in the few-electron regime. We report a characterization of the delayed electron backgrounds following energy depositions in the LZ detector under different detector conditions. In addition, we quantify the probability for photons to be emitted in coincidence with electron emission from the high voltage grids. We then demonstrate that spontaneous grid electron emission can be identified and rejected with a high efficiency using a coincident photon tag, which provides a tool to improve the sensitivity of future dark matter searches.
Read the full abstract

All authors D.S. Akerib, A.K. Al Musalhi, F. Alder, B.J. Almquist, C.S. Amarasinghe, A. Ames, T.J. Anderson, N. Angelides, H.M. Araújo, J.E. Armstrong, M. Arthurs, A. Baker, S. Balashov, J. Bang, J.W. Bargemann, E.E. Barillier, K. Beattie, T. Benson, A. Bhatti, T.P. Biesiadzinski, H.J. Birch, E. Bishop, G.M. Blockinger, B. Boxer, C.A.J. Brew, P. Brás, S. Burdin, M.C. Carmona-Benitez, M. Carter, A. Chawla, H. Chen, Y.T. Chin, N.I. Chott, S. Contreras, M.V. Converse, R. Coronel, A. Cottle, G. Cox, D. Curran, C.E. Dahl, I. Darlington, S. Dave, A. David, J. Delgaudio, S. Dey, L. de Viveiros, L. Di Felice, C. Ding, J.E.Y. Dobson, E. Druszkiewicz, S. Dubey, C.L. Dunbar, S.R. Eriksen, A. Fan, N.M. Fearon, N. Fieldhouse, S. Fiorucci, H. Flaecher, E.D. Fraser, T.M.A. Fruth, R.J. Gaitskell, A. Geffre, J. Genovesi, C. Ghag, A. Ghosh, S. Ghosh, R. Gibbons, S. Gokhale, J. Green, M.G.D.van der Grinten, J.J. Haiston, C.R. Hall, T. Hall, S.J. Haselschwardt, M.A. Hernandez, S.A. Hertel, G.J. Homenides, M. Horn, D.Q. Huang, D. Hunt, E. Jacquet, R.S. James, K. Jenkins, A.C. Kaboth, A.C. Kamaha, M.K. Kannichankandy, D. Khaitan, A. Khazov, J. Kim, Y.D. Kim, J. Kingston, D. Kodroff, E.V. Korolkova, H. Kraus, S. Kravitz, L. Kreczko, V.A. Kudryavtsev, C. Lawes, D.S. Leonard, K.T. Lesko, C. Levy, J. Lin, A. Lindote, W.H. Lippincott, J. Long, M.I. Lopes, W. Lorenzon, C. Lu, S. Luitz, P.A. Majewski, A. Manalaysay, R.L. Mannino, C. Maupin, M.E. McCarthy, D.N. McKinsey, J. McLaughlin, J.B. McLaughlin, R. McMonigle, B. Mitra, E. Mizrachi, M.E. Monzani, E. Morrison, B.J. Mount, M. Murdy, A.St.J. Murphy, H.N. Nelson, F. Neves, A. Nguyen, C.L. O'Brien, F.H. O'Shea, I. Olcina, K.C. Oliver-Mallory, J. Orpwood, K.Y Oyulmaz, K.J. Palladino, N.J. Pannifer, N. Parveen, S.J. Patton, B. Penning, G. Pereira, E. Perry, T. Pershing, A. Piepke, S.S. Poudel, Y. Qie, J. Reichenbacher, C.A. Rhyne, G.R.C. Rischbieter, E. Ritchey, H.S. Riyat, R. Rosero, T. Rushton, D. Rynders, S. Saltão, D. Santone, A.B.M.R. Sazzad, R.W. Schnee, G. Sehr, B. Shafer, S. Shaw, K. Shi, T. Shutt, C. Silva, G. Sinev, J. Siniscalco, A.M. Slivar, R. Smith, V.N. Solovov, P. Sorensen, J. Soria, A. Stevens, T.J. Sumner, A. Swain, M. Szydagis, D.R. Tiedt, M. Timalsina, Z. Tong, D.R. Tovey, J. Tranter, M. Trask, K. Trengove, M. Tripathi, A. Usón, A.C. Vaitkus, O. Valentino, V. Velan, A. Wang, J.J. Wang, Y. Wang, L. Weeldreyer, T.J. Whitis, K. Wild, M. Williams, J. Winnicki, L. Wolf, F.L.H. Wolfs, S. Woodford, D. Woodward, C.J. Wright, Q. Xia, J. Xu, Y. Xu, M. Yeh, D. Yeum, W. Zha, H. Zhang, T. Zhang

Instrumentation and Detectors · Cross-listed from astro-ph.IM

CCAT: Design, Implementation, and Testing of a System to Read Out over 10,000 280 GHz KIDs using RFSoC Electronics

Darshan A. Patel, Yuhan Wang, Cody J. Duell et al. (+26 more)

Over the past decade, kinetic inductance detectors (KIDs) have emerged as a viable superconducting technology for astrophysics at millimeter and submillimeter wavelengths. KIDs spanning 210 - 850 GHz across seven instrument modules will be deployed in the Prime-Cam instrument of CCAT Observatory's Fred Young Submillimeter Telescope at an elevation of 5600 m on Cerro Chajnantor in Chile's Atacama Desert. The natural frequency-division multiplexed readout of KIDs allows hundreds of detectors to be coupled to a single radio frequency (RF) transmission line, but requires sophisticated warm readout electronics. The FPGA-based Xilinx ZCU111 radio frequency system on chip (RFSoC) offers a promising and flexible solution to the challenge of warm readout. CCAT uses custom packaged RFSoCs to read out KIDs in the Prime-Cam instrument. Each RFSoC can simultaneously read out four RF channels with up to 1,000 detectors spanning a 512 MHz bandwidth per channel using the current firmware. We use five RFSoCs to read out the >10,000 KIDs in the broadband 280 GHz instrument module. Here, we describe and demonstrate the readout hardware, software and pipeline for the RFSoC system. We present a detector position map of the 280 GHz module focal plane and preliminary averaged spectral responses of a small subset of detectors from the TiN and first Al arrays. These measurements demonstrate our ability to simultaneously readout thousands of detectors, validate the end-to-end performance of the readout and optical systems, and represent a critical step toward reading out the ~100,000 KIDs in Prime-Cam in its future full capacity configuration.
Read the full abstract

All authors Darshan A. Patel, Yuhan Wang, Cody J. Duell, Jason E. Austermann, James Beall, James R. Burgoyne, Scott Chapman, Steve K. Choi, Rodrigo G. Freundt, Eliza Gazda, Christopher Groppi, Zachary B. Huber, Johannes Hubmayr, Ben Keller, Lawrence T. Lin, Philip Mauskopf, Alicia Middleton, Michael D. Niemack, Cody Roberson, Adrian K. Sinclair, Ema Smith, Jeff van Lanen, Anna Vaskuri, Benjamin J. Vaughan, Eve M. Vavagiakis, Michael Vissers, Samantha Walker, Jordan Wheeler, Ruixuan Xie

Chemical Physics

Systematic improvement of trial states in phaseless auxiliary-field quantum Monte Carlo

Eirik F. Kjønstad, Yann Damour, Sandeep Sharma et al. (+1 more)

We extend the use of coupled cluster (CC) trial states in the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method beyond single and double excitations to include both triple and quadruple excitations. With this AFQMC/CC hierarchy, we are able to systematically benchmark the method's performance on molecular systems as the quality of the trial is improved. Our results show that the phaseless AFQMC energy improves systematically and is typically significantly more accurate than the energy of the underlying trial state. However, the relative improvement compared to the trial CC energy decreases as we ascend the CC hierarchy. As the CC wavefunction is usually further approximated when used as an AFQMC trial, we also explore the relationship between the components of the CC wavefunction and the resulting AFQMC/CC error. Our results suggest that improving the representation of the CC wave function in the AFQMC trial does not always lower the bias even when it increases the fidelity of the trial with the exact ground state.
Read the full abstract

All authors Eirik F. Kjønstad, Yann Damour, Sandeep Sharma, Garnet Kin-Lic Chan

Atmospheric and Oceanic Physics

Skill of Long-Range Forecasts of Ocean Wave Spectra from the Navy ESPC Version 2 System

W.E. Rogers and M.A. Janiga

We report the outcome of evaluations of the skill of long-range forecasts from the ocean wave model component of the Navy's global coupled modeling system. Specifically, the model output is taken from a single member of the ensemble system, and we evaluate the skill of predicting seven model "wave height" parameters, computed from: energy in four frequency bands, energy in all bands combined, swell energy, and wind sea energy. The model is evaluated using two methods of "ground truth". The first is a new instrument for measuring wave spectra from space, Surface Waves Investigation and Monitoring (SWIM). The second is analyses from the same model. We propose a new method of band-wise bias correction of the observational dataset, using in situ wave observations, with the numerical wave model used as an intermediary.
Read the full abstract

Optics

In-space manufacturing of optical lenses: Fluidic Shaping aboard the International Space Station

Omer Luria, Mor Elgarisi, Eytan Stibbe et al. (+12 more)

In-space manufacturing technologies are vital for enabling advanced space missions and addressing logistical limitations of space exploration. While additive manufacturing has progressed rapidly, it still falls short of delivering the ultra-smooth surfaces required for optical elements. Fluidic Shaping is a novel method that harnesses surface tension under microgravity to form optical components with exceptionally smooth surfaces. This study demonstrates the feasibility and potential of Fluidic Shaping as a method for manufacturing optical components in space through two experiments performed aboard the International Space Station (ISS) during the Ax-1 mission. The first experiment involved fabricating centimeter-scale polymer lenses, solidifying them via ultraviolet (UV) curing, and analyzing the resultant optics upon their return to Earth. While sub-nanometric surface smoothness was achieved, some polymer lenses displayed unexpected thermo-chemical deformations, indicating complex polymerization dynamics unique to the microgravity environment. In the second experiment, a large-scale, 172 mm diameter water lens was deployed, confirming Fluidic Shaping's scalability and demonstrating basic optical functionality through image analysis. These experiments collectively underline the technique's relevance for both small-scale optics and large-aperture applications. Our results highlight critical considerations for future research, including optimizing polymerization processes and refining liquid-handling methods to advance practical, in-space optical manufacturing capabilities.
Read the full abstract

All authors Omer Luria, Mor Elgarisi, Eytan Stibbe, Michael Lopez-Alegria, Crissy Canerday, Alexey Razin, Sivan Perl, Valeri Frumkin, Jonathan Ericson, Khaled Gommed, Daniel Widerker, Israel Gabay, Ruslan Belikov, Edward Balaban, Moran Bercovici

Physics and Society

Deep Generative Model for Human Mobility Behavior

Ye Hong, Yatao Zhang, Konrad Schindler et al. (+1 more)

Understanding and modeling human mobility is central to challenges in transport planning, sustainable urban design, and public health. Despite decades of effort, simulating individual mobility remains challenging because of its complex, context-dependent, and exploratory nature. Here, building on the activity-based view of daily mobility, we propose MobilityGen, a diffusion-based generative framework for simulating multi-attribute activity-travel sequences over days to weeks at large spatial scales. By linking behavioral attributes with environmental context, MobilityGen reproduces key patterns such as scaling laws for location visits, activity time allocation, and the coupled evolution of travel mode and destination choices. It reflects spatio-temporal variability and generates diverse and plausible mobility patterns consistent with the built environment. Beyond standard validation, MobilityGen enables analyses that have been difficult with earlier models, including how access to urban space varies across travel modes and how co-presence dynamics shape social exposure and segregation. Together, these results support an integrated, data-driven basis for fine-grained studies of human mobility behavior and its societal implications.
Read the full abstract

All authors Ye Hong, Yatao Zhang, Konrad Schindler, Martin Raubal

Physics and Society

Kinetic modeling of knowledge and wealth dynamics in national and global markets

Marzia Bisi, Martina Conte and Maria Groppi

We propose a kinetic model to describe the dynamical evolution of wealth and knowledge in national and global markets, starting from a microscopic description of individual interactions. The model is built upon interaction rules that account for a strong interdependence between the microscopic variables, influencing agents' trading and saving propensities, knowledge acquisition, and the stochastic market effects. We begin with a domestic market scenario and extend the framework to international trade, incorporating the possibility of individual transfers between different countries. The dynamics of the system are described through Boltzmann-type equations, which allow for a detailed study of the evolution of the agent distribution in each country. In this context, we study the evolution of macroscopic quantities of the system, focusing on the number density of individuals, and the mean wealth and knowledge of each population, and we discuss these results in relation to existing models in the literature. Finally, under a quasi-invariant trading limit, we derive simplified Fokker-Planck type equations that reveal some emergent behaviors of the system, including the formation of Pareto tails in the long-term wealth and knowledge distributions.
Read the full abstract

Computational Physics · Cross-listed from cond-mat.mtrl-sci

Local Order Average-Atom Interatomic Potentials

Chloe A. Zeller, Ronald E. Miller and Ellad B. Tadmor

This article describes an extension to the effective Average-Atom (AA) method for random alloys to account for local ordering (short-range order) effects by utilizing information from partial radial distribution functions. The new Local Order Average-Atom (LOAA) method is rigorously derived based on statistical mechanics arguments and validated for non-stoichiometric binary 2D hexagonal crystals and 3D FeNiCr and NiAl alloys whose ground state is obtained through Monte Carlo sampling. Material properties for these alloys computed from atomistic simulations using standard interatomic potentials (IPs) exhibit a strong dependence on local ordering that is captured by simulations with effective LOAA IPs, but not the original AA method. The advantage of LOAA is that it requires smaller system sizes to achieve statistically converged results and therefore enables the simulation of complex materials, such as high-entropy alloys, at a fraction of the computational cost of standard IPs.
Read the full abstract

Biological Physics

Nitrogen-doped carbon quantum dots enhance bacteria growth and biosensing signals

David Rutherford, Marketa Šlapal Bařinková, Jaroslav Kuliček et al. (+3 more)

Carbon quantum dots (CQDs) are known for their antibacterial properties and ability to inhibit bacteria growth. In the current study, we observed a dopant and concentration-dependency on the antibacterial effect of CQDs. High concentrations of CQDs completely inhibited bacteria growth yet low concentrations enhanced growth. Unlike undoped CQDs, nitrogen-doped CQDs (N-CQDs) enhanced bacteria growth in a concentration-dependant manner and nitrogen/iron co-doped CQDs (Fe/N-CQDs) resulted in growth profiles similar to untreated bacteria. N-CQDs also exhibited the strongest photoluminescence (PL) signal which was quenched by bacteria, and the reduction in the maximum PL intensity was linear over the concentration range tested until saturation. N-CQDs were found to be located around the bacteria cell periphery suggesting intimate interactions. Illumination prior to interaction with bacteria had little influence on these growth effects. Absorbance measurements of colloidal CQD, N-CQD and Fe/N-CQD confirmed long-term stability (7 days). Such materials have potential for incorporation into rapid sensing and diagnostic systems for bacteria detection in liquids for biomedical applications.
Read the full abstract

All authors David Rutherford, Marketa Šlapal Bařinková, Jaroslav Kuliček, Jelena Kozic, Jovana Prekodravac Filipović, Bohuslav Rezek

Chemical Physics

A unified framework for semiclassical reaction rate theory

Joseph E. Lawrence

A general semiclassical theory for the calculation of reaction rate constants is developed. The theory can be understood as a formal framework that encompasses existing semiclassical methods: instanton theory and semiclassical transition state theory (SCTST). Unlike SCTST, the present formalism does not start from the concept of "good" action-angle variables. Instead, it is based on a conjectured connection between the cumulative reaction probability and the instanton contribution to the formally exact generalisation of Gutzwiller's formula for the trace of the Green's function. The formalism effectively generalises the "imaginary free-energy" formulation of instanton theory to microcanonical scattering rates and all orders in $\hbar$. In one dimension, explicit expressions are derived for the generalised reduced action up to $O(\hbar^4)$ using exact WKB/quantum Hamilton-Jacobi theory. The connection between the present formalism and the standard second order vibrational perturbation theory (VPT2) version of SCTST is explored. It is also shown that the standard thermal instanton rate theory, as well as higher order (dividing surface independent) "perturbative" corrections can be straightforwardly derived from the framework. Above the crossover temperature, first-order corrections in $\hbar$ to the parabolic barrier ("sphaleron") rate are also derived. A simple anharmonic transition state theory and anharmonic version of the Wigner tunneling correction are presented. Finally, the potential for the development of new and improved semiclassical methods for modelling reaction kinetics is discussed.
Read the full abstract

Applied Physics

Physical learning in reprogrammable metamaterials for adaptation to unknown environments

Kai Jun Chen, Catherine Catrambone, Christopher Sowinski et al. (+5 more)

Reprogrammable mechanical metamaterials, composed of a lattice of discretely adaptive elements, are emerging as a promising platform for mechanical intelligence. To operate in unknown environments, such structures must go beyond passive responsiveness and embody traits of mechanical intelligence: sensing, computing, adaptation, and memory. However, current approaches fall short, as computation of the required adaptation in response to changes in environmental stimuli must be pre-computed ahead of operation. Here we present a physical learning approach that harnesses the structure's mechanics to perform computation and drive adaptation. The desired global deformation response of nonlinear metamaterials with adaptive stiffness is physically encoded as local strain targets across internal adaptive elements. The structure adapts by iteratively interacting with the environment and updating its stiffness distribution using a model-free algorithm. The resulting system demonstrates autonomous real-time adaptation (~seconds) to previously unknown loading conditions without pre-computation. Physical learning inherently accounts for manufacturing imperfections and is robust to sensor noise and structural damage. We also demonstrate scalability to complex metamaterial structures and different metamaterial architectures. By uniting sensing, computation, and actuation in a mechanical framework, this work makes key strides towards embodying the traits of mechanical intelligence into adaptive structures. We expect our approach to open pathways towards in-situ adaptation to unknown environment for applications in hypersonic flight, adaptive robotics, and exploration in extreme environments.
Read the full abstract

All authors Kai Jun Chen, Catherine Catrambone, Christopher Sowinski, Jacob Mukobi, Enzo Andreacchio, Enquan Chew, Alexandre Morland, Maria Sakovsky

Chemical Physics · Cross-listed from cond-mat.mes-hall

Many-Body Effects in a Molecular Quantum NAND Tree

Justin P. Bergfield

Molecules provide the smallest possible circuits in which quantum interference and electron correlation can be engineered to perform logical operations, including the universal NAND gate. We investigate a chemically encoded quantum NAND tree based on alkynyl-extended iso-polyacetylene backbones, where inputs are set by end-group substitution and outputs are read from the presence or absence of transmission nodes. Using quantum many-body transport theory, we show that NAND behavior persists in the presence of dynamic correlations, but that the nodal positions and their chemical shifts depend sensitively on electron-electron interactions. This sensitivity highlights the potential of these systems not only to probe the strength of electronic correlations but also to harness them in shaping logical response. The thermopower is identified as a chemically robust readout of gate logic, providing discrimination margins that greatly exceed typical experimental uncertainties, in an observable governed primarily by the variation of transport rather than its absolute magnitude.
Read the full abstract

Applied Physics

Neutron-Assisted Breakdown Enhancement in $\beta$-Ga$_2$O$_3$ Schottky Diodes

Saleh Ahmed Khan, Sudipto Saha, Ahmed Ibreljic et al. (+6 more)

This study demonstrates a substantial enhancement of breakdown voltage in $\beta$-Ga$_2$O$_3$ Schottky diodes through an approach that combines fast neutron irradiation with controlled post-irradiation electro-thermal annealing. Devices irradiated with 1 MeV neutrons at a high fluence of 1E15 n/cm^2 exhibited substantial degradation, including a drastic reduction in on-current and an increase in on-resistance. Electrothermal testing, conducted through simultaneous current-voltage (J-V) measurements and thermal annealing, resulted in significant recovery. After four cycles of electro-thermal testing, the devices demonstrated significant improvements in performance, with a substantial recovery of on-current and a reduction in on-resistance compared to the post-radiation condition, approaching pre-radiation levels. Most recovery occurred during the first two cycles, with diminishing improvements in later cycles, indicating that most thermally recoverable traps were mitigated early. Capacitance-voltage (C-V) measurements revealed a substantial reduction in carrier concentration, decreasing from 3.2E16 cm^-3 pre-radiation to 5.5E15 cm^-3 after the first electro-thermal testing cycle, indicating an over 82% reduction. Following the third cycle, the carrier concentration partially recovered to 9.9E15 cm^-3, reflecting a carrier removal rate of ~22 cm^-1. The breakdown voltage exhibited a remarkable enhancement, increasing from approximately 300 V to 1.28 kV (a ~325% improvement) after the first electro-thermal testing, attributed to the reduction in carrier concentration by compensating radiation-induced traps. Subsequent testing reduced breakdown voltage slightly to 940 V due to partial recovery of carrier concentration, but it remained significantly higher than pre-radiation levels.
Read the full abstract

All authors Saleh Ahmed Khan, Sudipto Saha, Ahmed Ibreljic, Stephen Margiotta, Jiawei Liu, Walid Amir, Surajit Chakraborty, Uttam Singisetti, A F M Anhar Uddin Bhuiyan

Applied Physics · Cross-listed from quant-ph

Prediction of Molecular Single-Photon Emitters: A Materials-Modelling Approach

Erik Karlsson Öhman, Daqing Wang, R. Matthias Geilhufe et al. (+1 more)

Interfacing light with quantum systems is an integral part of quantum technology, with the most essential building block being single-photon emitters. Although various platforms exist, each with its individual strengths, molecular emitters boast a unique advantage – namely the flexibility to tailor their design to fit the requirements of a specific task. However, the characteristics of the vast space of possible molecular configurations are challenging to understand and explore. Here, we present a theoretical and computational framework to initiate exploration of this vast potential by integrating database analysis with microscopic predictions. Using a model system of dibenzoterrylene in an anthracene host as benchmark, our approach identifies promising new candidates, among them a chiral molecular emitter. Future extensions of our approach integrated with machine learning routines hold the promise of ultimately unlocking the full potential of molecular quantum light-matter interfaces.
Read the full abstract

All authors Erik Karlsson Öhman, Daqing Wang, R. Matthias Geilhufe, Christian Schäfer

Computational Physics · Cross-listed from cond-mat.soft

Phase segregation of liquid-vapor systems with a gravitational field

A. Lamura

Phase separation in the presence of external forces has attracted considerable attention since the initial works for solid mixtures. Despite this, only very few studies are available which address the segregation process of liquid-vapor systems under gravity. We present here an extensive study which takes into account both hydrodynamic and gravitational effects on the coarsening dynamics. An isothermal formulation of a lattice Boltzmann model for a liquid-vapor system with the van der Waals equation of state is adopted. In the absence of gravity, the growth of domains follows a power law with the exponent $2/3$ of the inertial regime. The external force deeply affects the observed morphology accelerating the coarsening of domains and favoring the liquid accumulation at the bottom of the system. Along the force direction, the growth exponent is found to increase with the gravity strength still preserving sharp interfaces since the Porod's law is found to be verified. The time evolution of the average thickness $L$ of the layers of accumulated material at confining walls shows a transition from an initial regime where $L \simeq t^{2/3}$ ($t$: time) to a late-time regime $L \simeq g t^{5/3}$ with $g$ the gravitational acceleration. The final steady state, made of two overlapped layers of liquid and vapor, shows a density profile in agreement with theoretical predictions.
Read the full abstract

Applied Physics

A Flux-Tunable Discrete Angular Filter

Tristan M. Lawrie and Oliver M. Brown

Recent work by Lawrie et al. [PRR 7, 023209 (2025)] introduced a non-diffracting resonant angular filter on a network of thin channels (modelled via quantum graph theory) that exhibits unit transmission of acoustic waves at a discrete, symmetry-paired set of incidence angles determined solely by the graph topology, while transmission at all other angles is strictly forbidden. In the present work, we study the same filtering geometry for waves governed by the magnetic Schrödinger equation rather than the classical wave equation. Using a phase shift induced by non-reciprocal wave propagation due to the presence of the magnetic potential and tuning $\delta$-type vertex boundary conditions, we make the previously topology-fixed discrete pass directions continuously tunable: both the transmission angle and the transmission coefficient become control parameters. The resulting flux-tunable angular filtering device replaces topology-constrained passbands with a programmable steering device, broadening the scope for wave-filter and beam-shaping applications.
Read the full abstract

Fluid Dynamics

Stability of vortex lattices in rotating flows

Julián Amette Estrada, Alexandros Alexakis, Marc E. Brachet et al. (+1 more)

Vortex lattices – highly ordered arrays of vortices – are known to arise in quantum systems such as type II superconductors and Bose-Einstein condensates. More recently, similar arrangements have been reported in classical rotating fluids. However, the mechanisms governing their formation, stability, and eventual breakdown remain poorly understood. We explore the dynamical stability of vortex lattices in three-dimensional rotating flows. To that end we construct controlled initial conditions consisting of vortex lattices superimposed on turbulent backgrounds. We then characterize their evolution across different Rossby numbers and domain geometries. By introducing an Ekman drag we are able to reach a steady state where vortex lattices persist with near constant amplitude up until spontaneous breakup of the lattice, or an equivalent of “melting,” occurs. We examine an ensemble of runs in order to determine the mean lifetime of the lattice as a function of the system parameters. Our results reveal that the stability of the lattices is a memory-less random process whose mean life-time depends sensitively on the system parameters that if finely tuned can lead to very long lived lattice states. These metastable states exhibit statistical properties reminiscent of critical systems and can offer insight into long-lived vortex patterns observed in planetary atmospheres.
Read the full abstract

All authors Julián Amette Estrada, Alexandros Alexakis, Marc E. Brachet, Pablo D. Mininni

Computational Physics · Cross-listed from cs.LG

Lagrangian neural ODEs: Measuring the existence of a Lagrangian with Helmholtz metrics

Luca Wolf, Tobias Buck and Bjoern Malte Schaefer

Neural ODEs are a widely used, powerful machine learning technique in particular for physics. However, not every solution is physical in that it is an Euler-Lagrange equation. We present Helmholtz metrics to quantify this resemblance for a given ODE and demonstrate their capabilities on several fundamental systems with noise. We combine them with a second order neural ODE to form a Lagrangian neural ODE, which allows to learn Euler-Lagrange equations in a direct fashion and with zero additional inference cost. We demonstrate that, using only positional data, they can distinguish Lagrangian and non-Lagrangian systems and improve the neural ODE solutions.
Read the full abstract

Chemical Physics · Cross-listed from quant-ph

Quantum matrix arithmetics with Hamiltonian evolution

Christopher Kang and Yuan Su

The efficient implementation of matrix arithmetic operations underpins the speedups of many quantum algorithms. We develop a suite of methods to perform matrix arithmetics – with the result encoded in the off-diagonal blocks of a Hamiltonian – using Hamiltonian evolutions of input operators. We show how to maintain this $\textit{Hamiltonian block encoding}$, so that matrix operations can be composed one after another, and the entire quantum computation takes $\leq 2$ ancilla qubits. We achieve this for matrix multiplication, matrix addition, matrix inversion, Hermitian conjugation, fractional scaling, integer scaling, complex phase scaling, as well as singular value transformation for both odd and even polynomials. We also present an overlap estimation algorithm to extract classical properties of Hamiltonian block encoded operators, analogous to the well known Hadamard test, at no extra cost of qubit. Our Hamiltonian matrix multiplication uses the Lie group commutator product formula and its higher-order generalizations due to Childs and Wiebe. Our Hamiltonian singular value transformation employs a dominated polynomial approximation, where the approximation holds within the domain of interest, while the constructed polynomial is upper bounded by the target function over the entire unit interval. We describe a circuit for simulating a class of sum-of-squares Hamiltonians, attaining a commutator scaling in step count, while leveraging the power of matrix arithmetics to reduce the cost of each simulation step. In particular, we apply this to the doubly factorized tensor hypercontracted Hamiltonians from recent studies of quantum chemistry, obtaining further improvements for initial states with a fixed number of particles. We achieve this with $1$ ancilla qubit.
Read the full abstract

Optics

Interpretation of measured 3x3 partial depolarizing Mueller matrices

Jose J. Gil, Ignacio San Jose, Monica Canabal-Carbia et al. (+3 more)

Mueller polarimetry is a powerful technique with broad applications in astronomy, remote sensing, advanced material analysis, and biomedical imaging. However, instrumental constraints frequently restrict the measurement to an incomplete Mueller matrix limited to its upper-left 3x3 submatrix. Simply padding the missing entries with zeros to form a 4x4 matrix can produce physically inconsistent results, even for nondepolarizing systems. To address this issue, we present a systematic procedure to complete 3x3 measured Mueller matrices into physically consistent 4x4 matrices. The method relies on the covariance matrix formalism and selects, among the infinitely many admissible completions, the one with maximal polarimetric purity. This criterion ensures that the synthesized matrix corresponds to the least random (most deterministic) model compatible with the measurement. The procedure is fully general and can be applied to any 3x3 partial Mueller polarimetric data, providing a reliable and physically grounded reconstruction tool for polarimetric imaging and materials characterization.
Read the full abstract

All authors Jose J. Gil, Ignacio San Jose, Monica Canabal-Carbia, Juan Campos, Angel Lizana, Irene Estevez

General Physics

Charged galactic wormholes: shadow imaging, accretion disks, and charged-particle deflection

Md Khalid Hossain, Humaun Kabir Laskar, Farook Rahaman et al. (+1 more)

We investigate the gravitational deflection of charged massive particles by a charged galactic wormhole supported by the Sofue dark matter density profile \cite{r57}, $\rho(r)=\rho_0 e^{-r/r_0},$ where $\rho_0$ and $r_0$ denote the central dark matter density and the characteristic scale radius, respectively. This phenomenological profile models the dark matter distribution in galactic halos and acts as the matter source sustaining the wormhole geometry. Extending our previous investigation of light rays and neutral massive particles in this spacetime \cite{b1}, we study the combined effects of gravitational and electromagnetic interactions on the motion of charged massive particles. The deflection angle is computed independently using the Rindler–Ishak method based on the Jacobi metric and the Gauss–Bonnet theorem, enabling a systematic comparison between the two approaches. We find that the predictions of the two methods become nearly indistinguishable in the relativistic regime, whereas the differences at lower velocities arise from the velocity-dependent correction terms proportional to $(1-v^2)$ in the trajectory equation. We further perform backward relativistic ray tracing of optically thin accretion flows around the charged galactic wormhole to investigate its shadow and photon-ring structure. Although the shadow remains circular because of the spacetime's spherical symmetry, its radius, photon-ring structure, and intensity distribution exhibit a nontrivial dependence on the wormhole charge, providing potential observational signatures of charged galactic wormholes. These results provide new insights into the interplay between gravitational and electromagnetic interactions in charged wormhole spacetimes and their observational manifestations.
Read the full abstract

All authors Md Khalid Hossain, Humaun Kabir Laskar, Farook Rahaman, Aritra Sanyal

Instrumentation and Detectors

Ultracold Neutron Guide-Coating Facility at U.Winnipeg

T. Hepworth, A. Zahra, B. Algohi et al. (+72 more)

We report the construction and commissioning of a new ultracold neutron (UCN) guide-coating facility at the University of Winnipeg. The facility employs pulsed laser deposition (PLD) to produce diamond-like carbon (DLC) coatings on cylindrical UCN guides up to 1 m in length with a 200 mm outer diameter. DLC is a promising material for UCN transport and storage due to its high real component of the optical potential, low neutron absorption cross section, and low depolarization probabilities. First coating attempts on a full length aluminum UCN guide and matching blank flange were successfully coated with a carbon film with density of 2.3 g/cm$^3$, corresponding to optical potentials of 200 neV, as measured by X-ray reflectometry (XRR). Coating thicknesses were measured to be 90 nm for the UCN guide and 180 nm for the flange with no evidence of delamination. The implementation of a plasma plume collimator and plasma feed back control via a time of flight in vacuum ion probe produced a film with an XRR measured density of 2.8 g/cm$^3$, corresponding to an optical potential of 240 neV. This 80 nm thick film had poor adhesion to the aluminum tube substrate. These results establish a baseline for the coating facility. Ongoing and future work focuses on improving the diamond content of films and adhesion through plasma plume collimation, TOF ion probe feed back, and pre/post treatment methods with the goal of providing high quality DLC UCN guides for the TUCAN experiment at TRIUMF.
Read the full abstract

All authors T. Hepworth, A. Zahra, B. Algohi, R. de Vries, S. Pankratz, P. Switzer, T. Reimer, M. McCrea, J.W. Martin, R. Mammei, D. Anthony, L. Barrón-Palos, M. Bossé, M.P. Bradley, A. Brossard, T. Bui, J. Chak, R. Chiba, C. Davis, K. Drury, D. Fujimoto, R. Fujitani, M. Gericke, P. Giampa, C. Gibson, R. Golub, T. Higuchi, G. Ichikawa, I. Ide, S. Imajo, A. Jaison, B. Jamieson, M. Katotoka, S. Kawasaki, M. Kitaguchi, W. Klassen, E. Korkmaz, E. Korobkina, M. Lavvaf, T. Lindner, N. Lo, S. Longo, K.W. Madison, Y. Makida, J. Malcolm, J. Mammei, Z. Mao, C. Marshall, R. Matsumiya, E. Miller, M. Miller, K. Mishima, T. Mohammadi, T. Momose, M. Nalbandian, T. Okamura, R. Patni, R. Picker, K. Qiao, W.D. Ramsay, W. Rathnakela, D. Salazar, J. Sato, W. Schreyer, T. Shima, H.M. Shimizu, S. Sidhu, S. Stargardter, R. Stutters, I. Tanihata, Tushar, W.T.H. van Oers, N. Yazdandoost, Q. Ye, M. Zhao

Atmospheric and Oceanic Physics

Mass Conservation on Rails – Rethinking Physics-Informed Learning of Ice Flow Vector Fields

Kim Bente, Roman Marchant and Fabio Ramos

To reliably project future sea level rise, ice sheet models require inputs that respect physics. Embedding physical principles like mass conservation into models that interpolate Antarctic ice flow vector fields from sparse & noisy measurements not only promotes physical adherence but can also improve accuracy and robustness. While physics-informed neural networks (PINNs) impose physics as soft penalties, offering flexibility but no physical guarantees, we instead propose divergence-free neural networks (dfNNs), which enforce local mass conservation exactly via a vector calculus trick. Our comparison of dfNNs, PINNs, and unconstrained NNs on ice flux interpolation over Byrd Glacier suggests that "mass conservation on rails" yields more reliable estimates, and that directional guidance, a learning strategy leveraging continent-wide satellite velocity data, boosts performance across models.
Read the full abstract

Fluid Dynamics

Mapping surface height dynamics to subsurface flow physics in free-surface turbulent flow using a shallow recurrent decoder

Kristoffer S. Moen, Jørgen R. Aarnes, Simen Å. Ellingsen et al. (+1 more)

Near-surface turbulent flows beneath a free surface are reconstructed from sparse measurements of the surface height variation, by a neural network algorithm known as the SHallow REcurrent Decoder (SHRED). The reconstruction of turbulent flow fields from limited, partial, or indirect measurements remains a grand challenge in science and engineering. The central goal in such applications is to leverage easy-to-measure proxy variables in order to estimate quantities which have not been, and perhaps cannot in practice be, measured. In the application considered here, the aim is to use a sparse number of surface height point measurements of a flow field, or drone video footage of surface features, in order to infer the turbulent flow field beneath the surface. SHRED is a deep learning architecture that learns a delay-coordinate embedding from a few surface height (point) sensors and maps it, via a shallow decoder trained in a compressed basis, to full subsurface fields, enabling fast, robust training from minimal data. We demonstrate the SHRED sensing architecture on two types of turbulent data from recent studies [Aarnes et al. J. Fluid Mech. 1007, A38 (2025) and Babiker et al. Phys. Rev. Fluids 11, 054802 (2026), respectively]: fully resolved DNS data and PIV laboratory data from a turbulent water tank. SHRED is capable of robustly mapping surface height fluctuations to full-state flow fields up to about one integral length scale deep, with as few as three surface measurements.
Read the full abstract

All authors Kristoffer S. Moen, Jørgen R. Aarnes, Simen Å. Ellingsen, J. Nathan Kutz

Applied Physics · Cross-listed from quant-ph

Optimised spectral purity of unfiltered photons via pump and nonlinearity shaping

Tommaso Faleo, Christopher L. Morrison, Roméo Beignon et al. (+6 more)

Photonic quantum technologies rely on the efficient generation and interference of indistinguishable photons. Exceptional achievements in this respect have been obtained by domain engineering of quasi-phase-matched parametric down-conversion sources, demonstrating high two-photon interference visibility using only moderate bandpass spectral filtering. Here, we optimised the spectral purity and indistinguishability of photons from telecom-wavelength sources by combining Gaussian quasi-phase-matching with Gaussian pump spectral shaping. Without spectral filtering, we used time-of-flight spectrometry to estimate an upper bound spectral purity of 99.9272(6)%, and achieved visibilities of up to 98.5(8)% in two-photon interference experiments with independent sources.
Read the full abstract

All authors Tommaso Faleo, Christopher L. Morrison, Roméo Beignon, Francesco Graffitti, Vikas Remesh, Stefan Frick, Alessandro Fedrizzi, Gregor Weihs, Robert Keil

Atmospheric and Oceanic Physics · Cross-listed from nlin.CD

Climate Model Tuning with Online Synchronization-Based Parameter Estimation

Jordan Seneca, Suzanne Bintanja and Frank M. Selten

In climate science, the tuning of climate models is a computationally intensive problem due to the combination of the high-dimensionality of the system state and long integration times. Supermodelling is a technique which has shown the potential for reducing climate model biases by dynamically coupling multiple models together, and training their coupling on a short timescale. Here, we introduce a new approach called adaptive supermodeling, where the internal model parameters of the member of a supermodel are tuned. We perform three experiments. We first directly optimize the internal parameters of a climate model. We then optimize the weights between two members of a supermodel in a classical supermodel approach. For a case designed to challenge the two previous methods, we implement adaptive supermodeling, which achieves a performance similar to a perfect model.
Read the full abstract

Optics

An integrated photonic millimeter-wave receiver with sub-ambient noise temperature

Junyin Zhang, Shuhang Zheng, Jiachen Cai et al. (+7 more)

Growing demands for timing precision in positioning systems, and resolution in atmospheric sensing and automotive radar, have extended receiver frontends into the millimetre-wave and THz regimes. At these frequencies, the noise performance of field-effect transistors used in low-noise amplifiers degrades rapidly due to parasitic effects, limited carrier mobility, hot electrons, and shot noise. Parametric transducers that couple electromagnetic signals to optical fields can offer quantum-limited sensitivity at room temperature. Electro-optic materials can enable receivers that transduce radiofrequency signals into optical phase shifts. Yet to date, room-temperature receivers using electro-optical detection have not attained a noise figure comparable to the electronic amplifiers. Here we demonstrate a room-temperature cavity electro-optic-based millimetre-wave receiver on a lithium tantalate photonic integrated circuit, achieving an on-chip photon-number transduction efficiency of 10%. The equivalent input-referred receiver-added noise temperatures reach $110\,\mathrm{K}$ on-chip and $202^{+35}_{-33}\,\mathrm{K}$ for the full system at 60.5 GHz, with noise figure matching state-of-the-art V-band electronic low-noise amplifiers. We resolve the thermal noise in cavity electro-optic transducers, showing that the system is limited by thermal photon occupation ($\sim$100) in the millimetre-wave cavity and optical vacuum noise, with no measurable excess noise. Our work demonstrates that integrated photonics can reach state-of-the-art electronic receiver noise performance while offering high-radiofrequency-power survivability and compatibility with remote optical readout. This establishes cavity electro-optics as a low-noise, electromagnetic interference-resilient, chip-scale receiver frontend for millimetre-wave applications, enabling scalable analogue processing in the optical domain.
Read the full abstract

All authors Junyin Zhang, Shuhang Zheng, Jiachen Cai, Connor Denney, Zihan Li, Yichi Zhang, Changhao Han, Xin Ou, Gabriel Santamaria-Botello, Tobias J. Kippenberg