Optics
Mapping the strong-to-weak coupling crossover in polymer-film microcavity lasers
Denis A. Sannikov, Nailya M. Urazova, Maksim D. Kolker et al. (+10 more)
Organic
semiconductors are particularly attractive for polaritonics due to their large
exciton binding energies and oscillator strengths. Among them, the ladder-type conjugated
polymer poly(paraphenylene) is distinguished by its rigid backbone, narrow
exciton linewidth, high photoluminescence
quantum yield, and enhanced photostability, making it an excellent candidate for organic polariton devices. While polariton lasing has been reported in various organic systems, systematic studies of the transition from polariton lasing to conventional
photon lasing within a single, well-controlled material platform remain limited. Here, we present planar organic microcavities incorporating MeLPPP as the active medium, in which continuous tuning of the effective cavity length within a single device enables us to map the strong-to-weak coupling transition across five distinct cavity-mode orders. We demonstrate an approximately eighteen-fold increase in the lasing threshold when crossing from polariton to
photon lasing. We further establish a quantitative framework in which the spectral dependence of the threshold governs a universal V-shaped blueshift of the emission energy across both coupling regimes. Finally, we show that vibron-mediated
exciton relaxation, previously identified in the strong-coupling limit, persists across the crossover: lasing-threshold minima track the vibron resonances throughout the coupling transition.
Read the full abstract ▾
All authors Denis A. Sannikov, Nailya M. Urazova, Maksim D. Kolker, Grigorij D. Ivanov, Anton D. Putintsev, Aleksandr V. Averchenko, Daria Khmelevskaia, Liliya T. Sahharova, Nikita S. Shlapakov, Ioannis Paschos, Pavlos G. Savvidis, Valentine P. Ananikov, Pavlos G. Lagoudakis
Atomic Physics
Collective excitation of Bose-Einstein condensate of Bose atoms with Pöschl-Teller interaction
Avra Banerjee, Arnab Bhowmik and Dwipesh Majumder
We investigate the collective excitations of Bose atoms in the condensate phase with finite-range interactions, modeled using the Pöschl-Teller (PT) potential to explicitly account for the finite interaction range. Utilizing Bogoliubov theory, we derive the excitation spectrum and examine its dependence on interaction parameters. Our analysis reveals that the emergence and disappearance of the roton minima are directly influenced by the range of the PT interaction. Furthermore, we calculate the static structure factor and find enhanced correlations in the low-momentum regime, with their nature controlled by the characteristics of the PT potential. We have examined the interaction dependence of sound velocity and compressibility in detail.
Read the full abstract ▾
Biological Physics · Cross-listed from cond-mat.soft
Physical Models of Embryonic Epithelial Healing
Rafael Almada, Nuno Araújo and Pedro Patrício
Embryonic healing in epithelial tissues is distinct from adult wound healing, as it lacks inflammatory responses or immune
cell recruitments, making it ideal to test models of wound healing driven primarily by epithelial dynamics. Many models have been developed to describe this process, ranging from simple mechanistic models to more elaborate multiscale simulations. We review different classes of physical models, from discrete to continuum models, and how they address key questions about the mechanics, signaling, and coordination of
cells during wound closure. We highlight tensions between model complexity and interpretability and discuss recent efforts to bridge gaps across scales. Finally, we identify directions for hybrid modeling and model-experiment integration that could push forward our understanding of epithelial repair in development and disease.
Read the full abstract ▾
Applied Physics · Cross-listed from quant-ph
An Industry-Academia Partnership for Advancing Quantum Frontiers: Perspective from the U.S. Center for Quantum Technologies
David Stewart, Gerardo Ortiz, Peter M. Kogge et al. (+2 more)
The U.S. Center for
Quantum Technologies (CQT) is a multi-university consortium established under the National Science Foundation's (NSF) Industry-University Cooperative Research Centers (IUCRC) program. Led jointly by Purdue University, Indiana University (both Bloomington and Indianapolis campuses), and the University of Notre Dame, CQT integrates academic research with industrial and governmental collaboration to accelerate
quantum innovation. This perspective outlines the consortium's strategic mission, interdisciplinary research agenda, and its role in shaping the future of
quantum-enabled technologies through collaborative development, translational impact, and workforce cultivation.
Read the full abstract ▾
All authors David Stewart, Gerardo Ortiz, Peter M. Kogge, Ricardo S. Decca, Tongcang Li
Atomic Physics · Cross-listed from quant-ph
Efficient lambda-enhanced gray molasses using an EIT-based laser locking scheme
Timothy Leese, Siobhan Patrick, Silvia Bergamini et al. (+1 more)
We present a novel implementation of lambda-enhanced gray molasses cooling in a non-standard beam geometry and with an inexpensive
laser locking set-up. In contrast to the established use of resource-intensive phase locking methods, our
laser system uses two independent
lasers, frequency -locked to a spectral feature produced by an electromagnetically induced transparency (EIT) resonance. We show that this approach achieves sufficient coherence to enable effective gray molasses cooling without the need for costly GHz electronics, significantly reducing the complexity and cost of experimental setups and represents a step toward more accessible cold atom technologies. A wave-function Monte Carlo analysis supports the experimental findings, offering insight into the cooling dynamics of this unconventional scheme
Read the full abstract ▾
All authors Timothy Leese, Siobhan Patrick, Silvia Bergamini, Calum MacCormick
Accelerator Physics
Introduction to Optics Design
Guido Sterbini
This lecture provides an overview of the principles and methodologies involved in linear optics design. It aims to introduce key concepts such as the
matrix formalism, the symplecticity, the quantities that are preserved in the single particle
evolution, e.g., the Courant-Snyder invariant. It also covers the concept of beam emittance and matching conditions for an ensemble of particles. The goal is to equip readers with the foundational tools needed for both theoretical understanding and practical application in linear optics and accelerator design.
Read the full abstract ▾
Fluid Dynamics
Stable stratification enhances transient growth in streaky shear flows
Will Oxley and Rich Kerswell
Recent work has found that the well-known `lift-up' mechanism is not important for, and may even inhibit, the transient growth possible on streaky wall-bounded shear flows which is believed an important process in the near-wall cycle for turbulent flows. Moreover, artificially removing the wall-normal velocity has been found to unleash 3 orders of magnitude more perturbation energy growth in an unbounded streaky flow model. Motivated by this, we examine the effect of introducing stable stratification which naturally suppresses wall-normal velocities (the `vertical' shear case) and find it permits the hugely enhanced linear energy growth predicted by simply removing the wall-normal velocity. Alternatively, imposing stable stratification such that the spanwise velocities are suppressed (`horizontal shear') not surprisingly inhibits transient growth by weakening the active `push over' mechanism. A formula for the critical stratification strength to completely suppress the preferred growth mechanism is determined which proves a useful predictor for what is seen in the full numerical solutions of the model. Implications for a stratified near-wall cycle are briefly discussed.
Read the full abstract ▾
Instrumentation and Detectors
Evaluation of 3D pixel silicon sensors for the CMS Phase-2 Inner Tracker
The Tracker Group of the CMS Collaboration
The high-luminosity upgrade of the CERN LHC requires the replacement of the CMS tracking detector to cope with the increased radiation fluence while maintaining its excellent performance. An extensive R&D program, aiming at using 3D pixel silicon sensors in the innermost barrel layer of the detector, has been carried out by CMS in collaboration with the FBK (Trento, Italy) and CNM (Barcelona, Spain) foundries. The sensors will feature a pixel
cell size of \mbox{$25\times100~\mu m^2$}, with a centrally located electrode connected to the readout chip. The sensors are read out by the RD53A and CROCv1 chips, developed in 65~nm CMOS technology by the RD53 Collaboration, a joint effort between the ATLAS and CMS groups. This paper reports the results achieved in beam test experiments before and after irradiation, up to a fluence of approximately \mbox{\SI{2.6e16}{n_{eq}/\cm^{2}}}. Measurements of assemblies irradiated to a fluence of \mbox{\SI{1e16}{n_{eq}/\cm^{2}}} show a hit detection efficiency higher than 96% at normal incidence, with fewer than 2% of channels masked, across a bias voltage range greater than \SI{50}{V}. Even after irradiation to a higher fluence of \mbox{\SI{1.6e16}{n_{eq}/\cm^{2}}}, similar performance is maintained over a bias voltage range of \SI{30}{V}, remaining well within CMS requirements.
Read the full abstract ▾
Medical Physics
Five Years of Clinical Application of independent Monte Carlo-Based Patient-Specific Quality Assurance at the Maastro Proton Therapy Center
Ilaria Rinaldi, Giorgio Cartechini, Angelo Schiavi et al. (+6 more)
At the Maastro
Proton Therapy Center in Maastricht, patient-specific quality assurance (PSQA) using an independent GPU-accelerated Monte Carlo (MC) calculation has fully replaced conventional measurements, which are time-consuming and have limited sensitivity to clinically relevant errors. A fully automated and robust pipeline was developed, integrating two clinical workflows based on the fast MC code Fred. The system is fully operational, and automatic verification reports are part of daily clinical practice. The first workflow performs a pre-treatment dose recalculation in Fred using the planning CT and clinical plan. The second uses Fred with machine log files to verify the actually delivered dose. Both generate automatic reports for clinical review. Over five years, this workflow has become part of routine clinical operations, providing robust 3D dosimetric verification in heterogeneous anatomies. So far, Fred has recalculated more than 6000 pre-treatment plans and 3513 log file-based PSQA cases, saving an estimated 4090 hours of QA work. The pipeline identified true negatives and detected two planning-related failures that would have been missed by conventional measurements. No false positives or negatives were observed, confirming high accuracy and reliability. The MC-based PSQA pipeline offers an efficient, sensitive, and clinically meaningful alternative to measurement-based QA in pencil beam scanning
proton therapy. By eliminating routine measurements, it saves resources while improving patient safety and treatment quality. Five years of experience confirm that measurement-less MC-based PSQA is a viable and superior approach, providing full 3D verification and early error detection - a practical blueprint for other
proton therapy centres.
Read the full abstract ▾
All authors Ilaria Rinaldi, Giorgio Cartechini, Angelo Schiavi, Jan Gajewski, Nils Krah, Antoni Rucinski, Gloria Vilches Freixas, Vincenzo Patera, Sebastiaan Nijsten
Chemical Physics · Cross-listed from cond-mat.mtrl-sci
Surface Properties of Ga-Cu Based Liquid-Metal Alloys: Impact of Cu Dilution Topography and Reaction Conditions
Tzung-En Hsieh, Michael S. Moritz, Andreas Mölkner et al. (+10 more)
We studied the surface properties of Ga-Cu based
liquid metal
alloys, a promising material system for supported catalytically active
liquid metal solutions (SCALMS). The impact of Cu dilution in the (
liquid) Ga
matrix is in-detail investigated by X-ray and UV photoelectron spectroscopy (XPS/UPS) and Machine-Learned-Force Field (ML-FF) calculations. With decreasing Cu content, microscopic and macroscopic Ga-Cu model samples exhibit a shift of the Cu 2p core level line to higher binding energies (Eb) as well as a correspondingly shifted and narrowed d-band with respect to pure Cu, which we ascribe to site isolation. To study the property
evolution of Ga-Cu at SCALMS reaction conditions, i.e., where Cu is present in
liquid Ga, additional XPS measurements were performed between 100 and 500 oC. The observed Cu 2p shift to lower Eb is tentatively ascribed to changes in the local environment with increasing temperature, i.e. bond elongation, which is corroborated by ML-FF simulations. The increased Cu surface content at low temperatures is attributed to the presence of crystallized Cu-rich intermetallic compounds, as evidenced by transmission electron microscopy images. In an attempt to generalize the findings for filled d-band transition metals (TMs) in
liquid Ga also Ga-Ag and Ga-Au model systems were investigated. The observed insights may be another step of paving the way for an insight-driven development of low-temperature melting
liquid metals for heterogeneous catalysis.
Read the full abstract ▾
All authors Tzung-En Hsieh, Michael S. Moritz, Andreas Mölkner, Christoph Wichmann, Johannes Frisch, Julien Steffen, Caiden J. Parker, Vaishnavi Krishnamurthi, Torben Daeneke, Hans-Peter Steinrück, Andreas Görling, Christian Papp, Marcus Bär
History and Philosophy of Physics
Mathématiques et Mécanique à Strasbourg entre 1871 et 1939
D Huilier
The University of Strasbourg, fundamentally humanistic since its creation, has a complicated history, being sometimes German, sometimes French through the ages. If one focus, from 1871, on the area of mathematics, we can identify two periods. Political goals led to send high-level scientists, sometimes rather young, to develop theoretical, later applied mathematics, leading to a novel area, mechanics. The first period, under Prussian influence until 1918, will see the emergence of an Institute of mathematics such it was existing in Göttingen; the second, dominated by the French influence, will make Strasbourg an anteroom to positions at the prestigious Faculty of Sciences in Paris, the Sorbonne, the Academy of Sciences or the ENS. Present communication will give an inside, through its history, of the development of Mathematics in Strasbourg, prelude to emerging Mechanics and the creation of what will become the Institut de Mécanique des Fluides et des Solides en 2000.
Read the full abstract ▾
Optics
Generative model for information metamaterial design
Jun Ming Hou, Long Chen, Xuan Zheng et al. (+9 more)
Generative models such as AlphaFold and MatterGen can directly generate novel material structures with desired properties, accelerating the new materials discovery and revolutionizing the material design paradigm from traditional trial-and-error approach to intelligent on-demand generation. AlphaFold is focused on
protein prediction with specific aperiodic structures; while MatterGen is focused on predicting periodic and stable
crystal structures. The universal design of metamaterials is much more complicated, since it involves to design meta-atoms (similar to the periodic structures) and their arbitrarily inhomogeneous distributions in space. Here, we propose InfoMetaGen, a universal generative model for information metamaterial design, which combines a pre-trained foundation model with lightweight functional adapters to intelligently generate artificial structures on-demand spanning from meta-atoms to arbitrary space coding patterns. In contrast to conventional intelligent metamaterial design methods that require training dedicated models for specific functionalities, InfoMetaGen enables a single universal generative model capable of switching across diverse functionalities by fine-tuning the lightweight adapters, significantly improving both efficiency and generalizability. Experimental results demonstrate that InfoMetaGen can not only accelerate the diverse discovery of new metamaterials, but also achieve breakthroughs in metamaterial performance. This work fills the gap of universal generative framework in designing artificial materials, and opens up unprecedented opportunities to expand the capability of generative models from the passive discovery of microscopic natural material to the active creation of macroscopic artificial materials.
Read the full abstract ▾
All authors Jun Ming Hou, Long Chen, Xuan Zheng, Jia Wei Wu, Jian Wei You, Zi Xuan Cai, Jiahan Huang, Chen Xu Wu, Jian Lin Su, Lianlin Li, Jia Nan Zhang, Tie Jun Cui
Optics
Phase stabilization for long baseline interferometry of incoherent optical sources
Joshua J. Collier, David R. Gozzard, John S. Wallis et al. (+1 more)
The maximum baseline, and therefore resolution, of optical astronomical interferometers is limited by attenuation and phase noise within the optical path between the apertures and beam combiner, as well as the practical challenges of constructing optical delay lines more than a few hundred meters in length. We implement off-band phase stabilization on two fiber optic links of 85~km, creating a total baseline of 170~km. We show that the system is able to effectively phase stabilize signals from an incoherent pseudo-thermal source with a bandwidth of 11.2~nm. We are able to reduce the phase noise by 4-5 orders of magnitude between 1 and 100~Hz such that we could resolve an applied phase difference of 0.16~cycles per second with continuous measurement. We show that, with phase stabilization active, the interferometer is able to recover both first-order and second-order
photon correlations. These results demonstrate the feasibility of this technique for long-baseline optical and
quantum astronomical interferometers. The present results are limited by chromatic dispersion within the fiber, which can be mitigated using dispersion compensating modules.
Read the full abstract ▾
All authors Joshua J. Collier, David R. Gozzard, John S. Wallis, Benjamin P. Dix-Matthews
Biological Physics · Cross-listed from quant-ph
Agency cannot be a purely quantum phenomenon
Emily C. Adlam, Kelvin J. McQueen and Mordecai Waegell
What are the physical requirements for agency? We investigate whether a purely
quantum system (one evolving unitarily in a coherent regime without decoherence or collapse) can satisfy three minimal conditions for agency: an
agent must be able to create a world-model, use it to evaluate the likely consequences of alternative actions, and reliably perform the action that maximizes expected utility. We show that the first two conditions conflict with the no-cloning
theorem, which forbids copying unknown
quantum states: world-model construction requires copying information from the environment, and deliberation requires copying the world-model to assess multiple actions. Approximate cloning strategies do not permit sufficient fidelity or generality for agency to be viable in purely
quantum systems. The third agency condition also fails due to the linearity of
quantum dynamics. These results imply four key consequences. First, agency requires significant classical resources, placing clear constraints on its physical basis. Second, they provide insight into how classical
agents emerge within a
quantum universe. Third, they show that
quantum computers cannot straightforwardly simulate agential behavior without significant classical components. Finally, they challenge
quantum theories of agency, free will, and consciousness.
Read the full abstract ▾
Computational Physics · Cross-listed from cond-mat.mtrl-sci
Towards Universal Material Property Prediction with Deep Learning and Single-Descriptor electronic Density
Feng Chen, Shu Li, Xin Chen et al. (+3 more)
Owing to its high scalability and computational efficiency, machine learning methods have been increasingly integrated into various scientific research domains, including ab initio-based materials design. It has been demonstrated that, by incorporating modern machine learning
algorithms, one can predict material properties with practically acceptable accuracy. However, one of the most significant limitations that restrict the widespread application of machine learning is its lack of transferability, as a given framework is typically applicable only to a specific property. The origin of this limitation is rooted in the fact that a material's properties are determined by multiple degrees of freedom – and their complex interplay – associated with
nuclei and electrons, such as atomic type, structural
symmetry, and the number and
quantum states of the valence electrons, among others. The inherent complexity rules out the possibility of a single machine learning framework providing a full description of these critical quantities. In this paper, we develop a universal machine learning framework based solely on a physically grounded and theoretically rigorous descriptor – electronic charge density. Our framework not only enables accurate prediction of eight different material properties (with R$^2$ values up to 0.94), but also demonstrates outstanding multi-task learning capability, as prediction accuracy improves when more target properties are incorporated into a single training process, thereby indicating excellent transferability. These results represent a significant step toward realizing the long-standing goal of a universal machine learning framework for the unified prediction of all material properties.
Read the full abstract ▾
All authors Feng Chen, Shu Li, Xin Chen, Dennis Wong, Biplab Sanyal, Duo Wang
Atmospheric and Oceanic Physics
Investigating Buoyant Plume Dynamics Induced by Localized Fire-Simulated Heating over Plant Canopies Using LES
Ajinkya Desai, Antonio Quim Cervantes and Tirtha Banerjee
The interaction of a buoyant plume with a plant canopy results in turbulent flow features distinct from those in a grassland environment. In this work, we model the
turbulence dynamics of a buoyant plume in a homogeneous plant canopy with a crosswind using large-eddy simulations. As the plume interacts with the crosswind, we observe increased vorticity at the windward edge and tilted hair-pin-like vortical structures on the leeward side. Strong rotational cores, representing counter-rotating
vortex pairs (CVPs), form as the flow twists and spirals into the leeward side of the buoyancy source from either side. Flow patterns aloft exhibit helical motions as the CVPs aloft propagate downstream, trailing the plume. We also simulate a no-canopy environment to facilitate comparison. The plume tilts less steeply near the source in the canopy case due to the canopy drag and its leeward side is marked by flow recirculation near the canopy top, which obstructs the upstream flow as it approaches. Moreover, the plume transition from the rise phase to the bent-over phase is delayed due to the canopy's aerodynamic effects and the oscillatory behavior of the far-field mean plume centerline is more damped. Additionally, in the canopy environment, there is downward momentum transfer primarily via ejections above the canopy and sweeps within the canopy space, upstream of the plume centerline. On the leeward side, counter-gradient motions play a significant role in transferring momentum away from the buoyancy source, with outward interactions being most dominant. Contrarily, in the no-canopy environment, counter-gradient motions near the surface are flanked upstream by an ejection-dominated region and downstream by a sweep-dominated region. Insights into the distinct plume behavior in canopy vs. no-canopy environments are vital for comparing with experiments and refining fire behavior or plume rise models.
Read the full abstract ▾
Accelerator Physics
RFSoC Based LLRF System Design at ALS
Qiang Du, Shreeharshini Murthy, Victoria Moore et al. (+5 more)
The Advanced Light Source (ALS) at LBNL is upgrading several LLRF systems for its Linac and Sub-Harmonic Bunchers, where it is desired to have a unified LLRF system design to support various RF frequencies (at 125MHz, 500MHz and 3GHz) and configurations. This paper demonstrates an open-source, direct sampling RFSoC based LLRF system design, featuring: sample-to-sample Multi-Tile Synchronization, deterministic latency, digital up/down conversion, arbitrary waveform generation and acquisition, in-pulse closed loop control, timing and EPICS integration, modular RF frontend and hardware designs. Measured RF characteristics show that the RFSoC based LLRF system is able to meet the system requirements.
Read the full abstract ▾
All authors Qiang Du, Shreeharshini Murthy, Victoria Moore, Angel Jurado Lopez, Michael Chin, Shree Subhasish Basak, David Nett, Benjamin Flugstad
Atmospheric and Oceanic Physics
Scaling analysis for buoyant plumes over wildland fires
Ajinkya Desai, Antonio Quim Cervantes and Tirtha Banerjee
Tracking the structure and
geometric properties of a buoyant plume in crosswind is critical for managing smoke hazards and improving disaster mitigation decision-making. Plume features, such as tilt angle, height, and
curvature changes, are impacted by multiple forcing parameters, with canopy-induced
turbulence patterns adding complexity. This study examines how these parameters, reduced to fewer dimensionless groups, affect the plume centerline slope, both near the surface and in the far field. Results from large-eddy simulations, conducted in both canopy and no-canopy environments, explore power-law dependencies, based on prior formulations, between the slopes and dimensionless groups describing the (1) relative strength of the buoyancy source to ambient wind forcing, (2) plume
turbulence intensity relative to upstream
turbulence, and (3) canopy density and height. Near-surface slopes are an order of magnitude higher in the canopy cases, although their sensitivity to group (1) is similar across both environments. In the canopy cases, the near-surface slope follows a one-fourth power-law dependence with group (2). This effect is absent in the no-canopy case, reflecting differences in the momentum-flux structure near the source. Moreover, the canopy aerodynamic effects delay the plume transition from the rise phase into the far-field, bent-over phase; however, canopy effects diminish as buoyancy source strength increases. The near-surface plume slope exhibits a more complex dependence on canopy geometry, increasing almost linearly with the canopy height but showing weaker sensitivity to canopy drag. Our findings support the development of scaling laws for plume structures across varied vegetative landscapes and inform improved predictive modeling efforts.
Read the full abstract ▾
Instrumentation and Detectors
The BUTTON-30 detector at Boulby
J. Bae, M. Bergevin, E. P. Bernard et al. (+62 more)
The BUTTON-30 detector is a 30-tonne technology demonstrator designed to evaluate the potential of hybrid event detection, simultaneously exploiting both Cherenkov and scintillation light to detect particles produced in
neutrino interactions. The detector is installed at a depth of 1.1 km in the Boulby Underground Laboratory allowing to test the performance of this new technology underground in a low background environment. This paper describes the design and construction of the experiment.
Read the full abstract ▾
All authors J. Bae, M. Bergevin, E. P. Bernard, D. S. Bhattacharya, J. Boissevain, S. Boyd, K. Bridges, L. Capponi, J. Coleman, D. Costanzo, T. Cunniffe, S. A. Dazeley, M. V. Diwan, S. R. Durham, E. Ellingwood, A. Enqvist, T. Gamble, S. Gokhale, J. Gooding, C. Graham, E. Gunger, J. J. Hecla, W. Hopkins, I. Jovanovic, T. Kaptanoglu, E. Kneale, L. Lebanowski, K. Lester, V. A. Li, M. Malek, C. Mauger, N. McCauley, C. Metelko, R. Mills, A. Morgan, F. Muheim, A. Murphy, M. Needham, K. Ogren, G. D. Orebi Gann, S. M. Paling, A. F. Papatyi, A. Petts, G. Pinkney, J. Puputti, S. Quillin, B. Richards, R. Rosero, A. Scarff, Y. Schnellbach, P. R. Scovell, B. Seitz, L. Sexton, O. Shea, G.D. Smith, R. Svoboda, D. Swinnock, A. Tarrant, F. Thomson, J. N. Tinsley, C. Toth, M. Vagins, G. Yang, M. Yeh, E. Zhemchugov
Atomic Physics · Cross-listed from quant-ph
Autler-Townes spectroscopy of a Rydberg ladder
Tai Xiang, Yue-Hui Lu, Jacquelyn Ho et al. (+3 more)
Ladder-type two-
photon excitation of an atom from a ground state $|g\rangle$, to an intermediate excited state $|e\rangle$, and, finally, to a Rydberg state $|r\rangle$, has a variety of uses from
quantum information to sensing. A common scheme for detecting this transition optically is through electromagnetically induced transparency (EIT). However, in inverted wavelength schemes, where the ground-to-excited transition wavelength is shorter than the excited-to-Rydberg transition wavelength, the strength of the EIT feature on the lower-leg beam is strongly reduced in a Doppler-broadened medium. Here, we report on an alternative two-
photon spectroscopic feature, which we term the two-
photon Autler-Townes resonance, observed on the upper-leg beam. Compared to the EIT signal, this feature's superior signal-to-noise ratio allows one to resolve Rydberg resonances with principal
quantum number as high as $n=80$. We also show that such a feature can be utilized to generate an error signal for stabilizing the frequency of the upper-leg beam.
Read the full abstract ▾
All authors Tai Xiang, Yue-Hui Lu, Jacquelyn Ho, Tsai-Chen Lee, Zhenjie Yan, Dan M. Stamper-Kurn
Optics
Scalable Generalized Meta-Spanners Enabling Parallel Multitasking Optical Manipulation
Tianyue Li, Wenyu Gao, Boyan Fu et al. (+12 more)
Optical manipulation techniques offer exceptional contactless control but are fundamentally limited in their ability to perform parallel multitasking. To achieve high-density, versatile manipulation with subwavelength photonic devices, it is essential to sculpt light fields in multiple dimensions. Here, we overcome this challenge by introducing generalized optical meta-spanners (GOMSs) based on metasurfaces. Relying on complex-amplitude modulation, this platform generates lens-free, customizable optical fields that suppress diffractive losses. As a result, several advanced functionalities are simultaneously achieved, including longitudinally varying manipulation and in-plane spanner arrays, which outperforms the same operations realized by conventional donut-shaped orbital flows. Furthermore, the particle dynamics is reconfigurable simply by switching the input and output polarizations, facilitating robust multi-channel control. We experimentally validate the proposed approach by demonstrating single-particle dynamics and the parallel manipulation of particle ensembles, revealing exceptional stability for multitasking operations. These results demonstrate an ultracompact platform scalable to a much larger number of optical spanners, advancing metadevices from wavefront sculptors to particle manipulators. We envision that the GOMS will catalyze innovations in cross-disciplinary fields such as targeted drug delivery and
cell-level biomechanics.
Read the full abstract ▾
All authors Tianyue Li, Wenyu Gao, Boyan Fu, Tianhua Shao, Yuchao Fu, Siarhei Zavatski, Jeeban Kumar Nayak, Shaohui Yan, Xiaohao Xu, Shuming Wang, Baoli Yao, Zhenlin Wang, Shining Zhu, Olivier J. F. Martin, C. T. Chan
Fluid Dynamics
Statistical properties of compressible isothermal turbulence from sub- to supersonic conditions
F. Thiesset and C. Federrath
This paper investigates the statistical properties of isothermal
turbulence in both the subsonic and supersonic regimes. The focus is on the influence of the Mach number ($Ma$) and the Reynolds number ($Re$) on both the space-local and scale-dependent fluctuations of relevant gas variables, the density, velocity, their derivatives, and the kinetic energy. We carry out hydrodynamical simulations with explicit viscosity and therefore controlled $Re$. We confirm previous work that the probability density functions (PDFs) of the gas density are approximately log-normal and depend on $Ma$. In contrast, derivatives of the density and velocity field are sensitive to $Re$, with the probability of extreme events growing with $Re$. The PDFs of the density gradient and velocity divergence (dilatation) exhibit increasingly heavy tails with growing $Ma$, signalling enhanced internal intermittency. At sufficiently high $Ma$, the statistics of dilatation are observed to saturate at a level determined solely by $Re$, suggesting that turbulent dilatation becomes limited by viscous effects. We also examine the scale-by-scale distribution of kinetic energy through a compressible form of the Kármán-Howarth-Monin (KHM) equation. In the intermediate range of scales, a marked difference is found between subsonic and supersonic
turbulence: while Kolmogorov-like scaling applies in the sub- and transonic regimes, supersonic
turbulence aligns more closely with Burgers
turbulence predictions. The analysis of individual terms in the KHM equation highlights the role of the pressure-velocity coupling as an additional mechanism for converting kinetic energy from large to small scales. Moreover, the contributions of the KHM terms exhibit non-monotonic behaviour with increasing $Ma$, with dilatational effects becoming more pronounced and acting to oppose the cascade of kinetic energy.
Read the full abstract ▾
Atomic Physics
Compact Continuous Cold Atomic Beam from a Single Cell with 3D Cooling and Ultra-low Light Shift
Sheng-Zhe Wang, Qian-Lan Cai, Zhi-Xin Meng et al. (+2 more)
We report a compact single-
cell source of a continuous cold-atom beam with three-dimensional (3D) cooling. By integrating an off-axis moving optical molasses (OM) with a two-dimensional magneto-optical trap (MOT), we achieve simultaneous 3D cooling within a 50 mm interaction region. The source delivers a continuous flux up to 4.9(5)x10^9 atoms/s, with a transverse temperature of 94(5) microK, a longitudinal temperature as low as 231(65) microK, and a tunable mean velocity between 5 and 20 m/s. Custom in-
vacuum mirrors integrate the reflective geometry for the off-axis OM beams with a 0.8 mm output aperture, ensuring stable
alignment while suppressing stray light and fluorescence leakage. Ultra-low light shift and decoherence are verified via continuous Raman-Ramsey interferometry, yielding a light shift of -0.51(4)Hz and a typical fringe contrast of 90.85(30)% at a Raman separation of 100 mm (interrogation time of 8.70 ms). This compact continuous cold-atom beam source constitutes a practical building block for atomic-beam clocks and interferometers, enabling reduced aliasing noise together with improved sensitivity and accuracy for field applications.
Read the full abstract ▾
All authors Sheng-Zhe Wang, Qian-Lan Cai, Zhi-Xin Meng, Yi-Cheng Deng, Yan-Ying Feng
History and Philosophy of Physics · Cross-listed from math.HO
On Physical Mathematics: an approach through Gilles Châtelet's philosophy
John Alexander Cruz Morales
Starting from Greg Moore's description about Physical Mathematics, a framework is proposed in order to understand it, based on Gilles Châtelet's philosophy. It will be argued that Châtelet's ideas of inverting, splitting, augmenting and virtuality are crucial in the discussion about the nature of Physical Mathematics. Along this line, it will be proposed that mirror
symmetry is a natural study case to test Châtelet's ideas in this context. This should be considered as a first step in a long term project aiming to study the relations among mathematics, physics and philosophy in the construction of a global understanding of the structure of the universe, as it was envisioned by Grothendieck in the late 80's of the last century and it was started to be developed independently by Châtelet in the beginning of the 90's. The main suggestion of the essay is that it is in the relations between mathematics, physics and philosophy that new knowledge arises.
Read the full abstract ▾
Optics
Perfect Heat Rectification and Circulation with Nonreciprocal Radiative Surfaces in the Far Field
Sina Jafari Ghalekohneh and Bo Zhao
Controlling
photon mediated energy flow is central to the future of communications, thermal management, and energy harvesting technologies. Recent breakthroughs have revealed that many body systems violating Lorentz reciprocity can sustain persistent
photon heat current at thermal
equilibrium, hinting at a new paradigm of heat flow akin to superconductivity. Yet, the behavior of such systems far from
equilibrium remains largely unexplored. In this work, we uncover the rich physics of radiative heat transfer in nonequilibrium, far field many body systems composed of thermal emitters that break Lorentz reciprocity. We show that the total heat flow naturally decomposes into two distinct components: an
equilibrium term, which generates a persistent circulating heat current within the system, and a nonequilibrium term, which governs energy exchange with the environment. Remarkably, while the internal persistent heat current is ever present, the nonequilibrium contribution can be precisely engineered to achieve perfect heat rectification and circulation. Our results open a new route toward designing thermal systems with unprecedented control unlocking the potential for lossless heat circulation and one way thermal devices. This fundamentally shifts the landscape for next generation thermal logic, energy conversion, and photonic heat engines.
Read the full abstract ▾
Computational Physics
Long-Range Chiral Pairing enables Topological Superconductivity in Triangular Lattices without Spin-Orbit Coupling and Magnetic Field
Yizhi Li, Yanyan Lu, Jianxin Zhong et al. (+1 more)
This paper demonstrates a pathway to topological superconductivity in monolayer triangular
lattices through long-range pairing without requiring
spin-orbit coupling and
magnetic field, contrasting conventional frameworks reliant on superconductivity and
spin-orbit coupling and time-reversal
symmetry (TRS) breaking. Berry
curvature analysis reveals spontaneous TRS-breaking-induced peaks or valleys under long-range pairing, signaling nontrivial
topology superconducting state. Notably, the increase in the long-range pairing strength only changes the size of the energy band-gap, without triggering a topological phase transition. This characteristic is verified by calculating Berry
curvature and topological edge states. In zigzag and armchair-edge ribbons of finite width, the topological edge states are regulated by the ribbon boundary
symmetry and the interact range of long-range pairing. Under nearest-neighbor pairing, the topological edge states maintain particle-hole
symmetry and matches the corresponding Chern number. However, next-nearest-neighbor and third-nearest-neighbor pairings break the particle-hole
symmetry of the topological edge states in armchair-edge ribbon. This work proposes a mechanism for realizing topological superconductivity without relying on
spin-orbit coupling and
magnetic field, offering a theoretical foundation for simplifying the design of topological
quantum devices.
Read the full abstract ▾
All authors Yizhi Li, Yanyan Lu, Jianxin Zhong, Lijun Meng
Geophysics · Cross-listed from cond-mat.mtrl-sci
Melting phase relation of seifertite and pyrite-type SiO2 determined by machine learning potentials
Doyoon Park, Xin Deng and Jie Deng
Silica (SiO2) is fundamental to both industrial technology and planetary science, yet the phase relations of its high-pressure polymorphs remain poorly constrained. Here, we develop two machine learning potentials (MLPs) for SiO2 that faithfully represent the SCAN and PBEsol exchange-correlation functionals over a wide temperature (1000-10000 K) and pressure (100-400 GPa) range using deep neural networks. With large-scale two-phase simulations powered by these potentials, we determine the melting curves of seifertite and pyrite-type SiO2 and infer the solid-solid phase boundary between these two phases. The SCAN functional, which captures intermediate-range van der Waals interactions, reproduces structural and thermodynamic properties with high fidelity, predicting melting temperatures 6-10 % higher and a seifertite to pyrite-type transition pressure 22 % higher than the PBEsol. The strongly negative Clapeyron slope (-6.1 MPa/K) of this transition suggests that mantle convection could be highly layered in super-Earth
exoplanets, potentially affecting their long-term thermal
evolution and habitability.
Read the full abstract ▾
Computational Physics · Cross-listed from cs.LG
Neural Triangular Transport Maps: A New Approach Towards Sampling in Lattice QCD
Andrey Bryutkin and Youssef Marzouk
Lattice field theories are fundamental testbeds for computational physics; yet, sampling their Boltzmann distributions remains challenging due to multimodality and long-range correlations. While normalizing flows offer a promising alternative, their application to large
lattices is often constrained by prohibitive
memory requirements and the challenge of maintaining sufficient model expressivity. We propose sparse triangular transport maps that explicitly exploit the conditional independence structure of the
lattice graph under periodic boundary conditions using monotone rectified neural networks (MRNN). We introduce a comprehensive framework for triangular transport maps that navigates the fundamental trade-off between exact sparsity (respecting marginal conditional independence in the target distribution) and approximate sparsity (computational tractability without fill-ins). Restricting each triangular map component to a local past enables site-wise parallel evaluation and linear time complexity in
lattice size $N$, while preserving the expressive, invertible structure. Using $\phi^4$ in two dimensions as a controlled setting, we analyze how node labelings (orderings) affect the sparsity and performance of triangular maps. We compare against Hybrid Monte Carlo (HMC) and established flow approaches (RealNVP).
Read the full abstract ▾
Optics
Breaking On/Off-coupling Loss Degeneracies via Bidirectional Nonlinear Optics
Bo-Han Wu, Mahmoud Jalali Mehrabad, Mengjie Yu et al. (+1 more)
Accurate evaluation of nonlinear photonic integrated
circuits requires separating input and output coupling efficiencies (i.e., $\eta_1$ and $\eta_2$), yet the conventional linear-transmission calibration method recovers only their product (i.e., $\eta_1\,\eta_2$) and therefore introduces systematic bias when inferring on-chip performance from off-chip data. We present bidirectional nonlinear optical
tomography (BNOT), a direction-aware metrology that uses forward and backward pumping of complementary nonlinear probes, with process-appropriate detection, to break the “degeneracy” of $\eta_1\,\eta_2$ and estimate individual interface efficiencies with tight confidence intervals. The method links off-chip measurements to on-chip quantities through a compact observation model that explicitly incorporates pump fluctuations and detector noise, and it frames efficiency extraction as a joint constrained optimization. Monte Carlo studies show unbiased convergence of the estimated efficiencies to ground truth with low error across realistic operating regimes. Using these efficiency estimates to reconstruct on-chip nonlinear figures of merit yields distributions centered on the true values with reduced variance, whereas conventional “degenerate” calibration is biased and can substantially misestimate on-chip performance. BNOT is hardware-compatible and platform-agnostic, and provides unbiased characterization of off- and on-chip coupling efficiencies across nonlinear processes, enabling reproducible, coupling-resolved benchmarking for scalable systems in
quantum optics, frequency conversion, and precision metrology.
Read the full abstract ▾
All authors Bo-Han Wu, Mahmoud Jalali Mehrabad, Mengjie Yu, Dirk Englund
Computational Physics · Cross-listed from cond-mat.mtrl-sci
Large-gap quantum anomalous Hall insulator in two-dimensional pentagonal TiN$_8$ monolayer
Zheng Wang, Linda Sophie Reitz, Beichen Ruan et al. (+4 more)
Discovering the
quantum anomalous
Hall (QAH) effect in two-dimensional magnets is a central goal of topological condensed matter physics, yet candidate materials combining a sizable gap with a well-defined Chern number remain scarce. We report a new material platform that realizes emergent magnetism and nontrivial band
topology within the largely overlooked family of two-dimensional MN$_8$ monolayers. Through first-principles calculations, we reveal that these systems exhibit out-of-plane
magnetic ground states and nontrivial topological features driven by the localized $d$-orbitals of the embedded transition metals. Remarkably, we identify TiN$_8$ as a
quantum anomalous
Hall insulator characterized by a Chern number of $C=-1$ with a large topological gap of 223 meV. As a companion system, MoN$_8$ is predicted to be a rare high-Chern-number QAH
insulator, with a Chern number of $C=2$, although its much smaller gap of 12 meV renders it more fragile. These findings establish the penta-MN$_8$ family as a versatile and promising platform to realize exotic topological
quantum states. This work not only broadens the material landscape for
magnetic topological
insulators but also lays a solid theoretical foundation for the development of next-generation spintronic and
quantum computing devices.
Read the full abstract ▾
All authors Zheng Wang, Linda Sophie Reitz, Beichen Ruan, Zhuoheng Li, Shu-Shen Lyu, Richard Dronskowski, Kaixuan Chen