Optics
Constant-Amplitude $2\pi$ Phase Modulation from Topological Pole–Zero Winding
Alex Krasnok
Resonant phase shifters inevitably mix phase and amplitude. We present a topological synthesis that guarantees a full $2\pi$ phase swing at a prescribed constant scattering magnitude $|S_{ij}|=C$ by winding a scattering zero around the operating point in the complex-frequency plane while avoiding pole windings. We realize this either by complex-frequency waveform excitation on an iso-$|S_{ij}|$ (Apollonius) loop or by adiabatic co-modulation of detuning and decay at fixed carrier, suppressing AM–PM conversion and quantizing $\Delta\phi$ by the Argument Principle. The approach targets integrated resonant modulators, programmable photonic
circuits, and
quantum/beam-steering interferometers that require amplitude-flat phase shifts.
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Classical Physics · Cross-listed from math-ph
Hamilton-Jacobi as model reduction, extension to Newtonian particle mechanics, and a wave mechanical curiosity
Amit Acharya
The Hamilton-Jacobi equation of classical mechanics is approached as a model reduction of conservative particle mechanics where the velocity degrees-of-freedom are eliminated. This viewpoint allows an extension of the association of the Hamilton-Jacobi equation from conservative systems to general Newtonian particle systems involving non-conservative forces, including dissipative ones. A
geometric optics approximation leads to a dissipative Schrödinger equation, with the expected limiting form when the associated classical force system involves conservative forces.
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Plasma Physics
Multivariate scaling of proton and ion energies, divergence, and charge states in Target Normal Sheath Acceleration
Vasiliki E. Alexopoulou
The interaction of an intense
laser pulse with a solid target produces energetic
proton and ion beams through the Target Normal Sheath Acceleration (TNSA) mechanism. Such beams are under active investigation for applications in
proton beam therapy, materials modification, and
nuclear and high-energy-density physics. Despite extensive experimental and theoretical effort, predictive correlations between
laser and target parameters and the resulting ion-beam properties remain an open research question, owing to the intrinsically multiphysics and strongly coupled nature of
laser-
plasma interactions. Here, we employ our unified multiphysics model that reproduces
laser-solid interaction dynamics with accuracy exceeding 95% over a broad range of short- and ultrashort-pulse conditions. Using this model, we derive statistically validated scaling laws and probability maps that correlate
proton, carbon, and oxygen ion cutoff energies, beam divergences, and ionization states to a wide set of
laser and target parameters, including pulse duration,
laser power,
laser beam spot, target thickness, prepulse-main pulse interval, contrast,
laser wavelength, and polarization. Continuous beam properties (cutoff energies and beam divergences) are described using multivariate regression with cross-validation, while discrete ionization states are analyzed using classification and regression tree (CART) methods, enabling nonlinear and threshold-dependent behavior to be captured. The resulting scaling relations, contour maps, and box plots elucidate the coupled roles of
laser pulse, and target geometry in governing TNSA ion acceleration and charge-state formation. These results provide a predictive and physically interpretable framework for understanding and optimizing
laser-driven ion sources across a wide parameter space.
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Optics
Twist-Tuned Strong Coupling in Sub-GHz Wire Metasurface Bilayers
Ingrid Torres and Alex Krasnok
Twist-angle control offers a bias-free route to reconfigurable metasurfaces, yet its extension to deeply subwavelength resonant platforms at VHF/UHF remains limited. We demonstrate a sub-GHz double-layer wire metasurface formed by two identical wire grids separated by a gap G, with in-plane rotation angle as the sole tuning parameter. One-port, loop-coupled S11 measurements supported by full-wave simulations reveal twist-driven hybridization of the dominant resonant
manifold. For small G, the lower hybrid resonance
redshifts continuously from 409 MHz to 210 MHz (2:1 tuning), enabling compact, twist-programmable resonant surfaces. Simulations further show that twisting imprints moire-like
magnetic near-field super-modulations. From resonance frequencies, linewidths, and normal-mode splitting extracted from the complex response, we obtain normalized coupling up to g = 0.43 with cooperativity exceeding unity over broad angular ranges, meeting the resolved-splitting criterion. The rapid collapse of tunability at larger G confirms the near-field origin of the interaction.
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Optics
Coherently Assisted Wireless Power Transfer Through Poorly Transparent Barriers
Alex Krasnok
Poorly transparent barriers (e.g., reinforced walls, shielding panels, metallic or high-contrast dielectrics) strongly reflect incident radiation, limiting wireless power transfer (WPT) unless the barrier is structurally modified to support a narrowband transparency window. Here we introduce a barrier-agnostic alternative based on coherent scattering control: a phase-locked auxiliary wave is launched from the receiver side with an amplitude and phase chosen from the measured complex scattering parameters of the barrier. In a two-port (single-channel-per-side) description, we derive closed-form conditions for (i) canceling back-reflection toward the transmitter and (ii) maximizing the net extracted power at the receiver side. In the lossless limit these conditions imply unit transmitter-to-receiver efficiency (all transmitter power is routed to the receiver side) even when the barrier is nearly opaque under one-sided illumination. We validate the concept using (1) an analytically solvable high-index Fabry–Pérot slab and (2) a numerically simulated perforated PEC metasurface exhibiting vanishing one-sided transmission; in both cases, coherent assistance yields near-unity transmission and large enhancement factors. We further analyze dissipative barriers using a receiver-side energy-balance metric, showing that substantial net delivery can persist well into the lossy regime. The approach is closely related to coherent perfect absorption and time-reversal ideas in wave physics, but targets reflectionless delivery through barriers without modifying the obstacle itself.
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Fluid Dynamics
Observation of the Aharonov-Bohm Effect in Pilot-Wave Hydrodynamics
Georgi Gary Rozenman, Kyle I. McKee, Arnaud Lazarus et al. (+2 more)
We report the results of an experimental study of an analog of the Aharonov-Bohm (AB) effect achieved with the hydrodynamic pilot-wave system. A walking droplet is confined to an annular cavity that encircles a shielded
vortex, but lies outside its range of direct influence. While there is no
vortex-induced flow in the immediate vicinity of the droplets, the
vortex modifies the droplet's spatially extended pilot-wave field that guides its motion, producing a
vortex-dependent bias in the droplet's orbital speed. High-speed tracking and delay-
embedding reconstructions yield Wigner-like phase-space distributions for this hydrodynamic system that exhibits a rigid, flux-dependent translation, providing a force-free, gauge-like realization of an AB-type phase.
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All authors Georgi Gary Rozenman, Kyle I. McKee, Arnaud Lazarus, Valeri Frumkin, John W M Bush
Plasma Physics · Cross-listed from astro-ph.HE
Minijets and Broken Stationarity in a Blazar : Novel Insights into the Origin of $\gamma$-ray Variability in CTA 102
Agniva Roychowdhury
High-energy blazar light curves, in X-rays and beyond, have historically preferred a log-normal flux distribution, signifying multiplicative processes either in the jet itself or due to connection(s) with
accretion. Here we present 18 year archival
Fermi-LAT light curves (0.1-100 GeV) of the flat spectrum
radio quasar (FSRQ) CTA 102 from August 2008 to November 2025, which underwent a huge
flare in 2017, with a $\sim$ factor of 100 jump in $\gamma$-ray flux, along with similar flaring in X-rays. Our statistical analyses confirm that neither the pre nor the post-
flare total GeV light curves follow a strictly log-normal distribution. Instead, we observe a statistically significant reduction in skewness from the pre to the post-
flare light curves, which implies the blazar transitioned from an energetic state with frequent flaring to a more plateaued state with occasional flaring. We further find that this state transition can be explained through
magnetic relaxation, where many reconnection events caused the 2017
flare, after which the
magnetic field was ordered and its energy reached a minimum. To explain this further, we use a Monte Carlo simulation of a modified minijets-in-a-jet model where GeV
flares are produced only when a maximum number of minijets move toward the broad line region and towards the line of sight, in the context of an external Compton model. The flux distributions (both observed and simulated) could be fit by a modified log-normal power-law distribution, implying our minijets model can reproduce the GeV
flares in CTA 102 as well as their flux distributions.
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Accelerator Physics
Study of laser-beam arrival time synchronization towards sub-picosecond stability level
Konstantin Popov, Hiroshi Kaji, Tetsuya Kobayashi et al. (+7 more)
A precise synchronization between
laser pulse and electron beam arrival time is essential for achieving sub-picosecond stability in modern accelerator facilities. In this work, a Low-Level RF system architecture combined with White Rabbit based timing system has been tested through a collaboration between KEK (Japan) and CNRS/IN2P3, IJClab (France). The setup combines a frequency standard generator, an IDROGEN carrier board with an embedded White Rabbit node, and SkyWorks synthesizers of different form factors to distribute phase-locked clock signals over telecommunication fiber. Phase noise power spectral density measurements were performed at several RF sub-harmonics to confirm synchronization performance. These results demonstrate the feasibility of implementing the White Rabbit-IDROGEN synchronization scheme for large-scale accelerators, including applications to
laser-based diagnostics.
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All authors Konstantin Popov, Hiroshi Kaji, Tetsuya Kobayashi, Aurelien Martens, Daniel Charlet, Cedric Esnault, Antoine Back, Paul-Eric Pottie, Fabian Zomer, Alexander Aryshev
Instrumentation and Detectors
Operation of a tunable Power over Fiber system for light detectors down to 4.6 K
A.Andreani, C.Brizzolari, E.J.Cristaldo Morales et al. (+11 more)
The Power over Fiber (PoF) technology delivers electrical power by transmitting
laser light through a lightweight, non-conductive fiber optic cable to a remote photovoltaic optical converter, which in turn powers sensors or electrical devices. Among the several advantages offered by this solution are spark-free operation in the presence of electric fields, elimination of noise induced by power lines, immunity to electromagnetic interference, and high robustness in hostile environments. The R&D for the application of PoF in cryogenic environments started at FNAL and BNL (USA) in 2020 to power the
Photon Detection System of the DUNE Vertical Drift module. This paper presents the results obtained in the framework of Cryo-PoF project where we developed a single-
laser input line system to power an electronic amplifier and the photosensors at cryogenic temperatures. Unlike the DUNE solution, our system allows tuning of the photosensor bias by adjusting the input
laser power. We also demonstrate the operation of the optical converter at temperatures down to 4.6 K, opening the possibility of using this technology in a much broader range of applications.
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All authors A.Andreani, C.Brizzolari, E.J.Cristaldo Morales, M.J.Delgado Gonzalez, A.Falcone, N.Gallice, C.Gotti, M.Lazzaroni, L.Meazza, G.Pessina, D.Santoro, F.Terranova, M.Torti, V.Trabattoni
Optics · Cross-listed from quant-ph
All-optical control and multiplexed readout of multiple superconducting qubits
Xiaoxuan Pan, Chuanlong Ma, Jia-Qi Wang et al. (+12 more)
Superconducting
quantum circuits operate at millikelvin temperatures, typically requiring independent microwave cables for each
qubit for connecting room-temperature control and readout electronics. However, scaling to large-scale processors hosting hundreds of
qubits faces a severe input/output (I/O) bottleneck, as the dense cable arrays impose prohibitive constraints on physical footprint, thermal load, wiring complexity, and cost. Here we demonstrate a complete optical I/O architecture for superconducting
quantum circuits, in which all control and readout signals are transmitted exclusively via optical
photons. Employing a broadband traveling-wave Brillouin microwave-to-optical transducer, we achieve simultaneous frequency-multiplexed optical readout of two
qubits. Combined with fiber-integrated photodiode arrays for control signal delivery, this closed-loop optical I/O introduces no measurable degradation to
qubit coherence times, with an optically driven single-
qubit gate fidelity showing only a 0.19% reduction relative to standard microwave operation. These results establish optical interconnects as a viable path toward large-scale superconducting
quantum processors, and open the possibility of networking multiple superconducting
quantum computers housed in separate dilution refrigerators through a centralized room-temperature control infrastructure.
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All authors Xiaoxuan Pan, Chuanlong Ma, Jia-Qi Wang, Zheng-Xu Zhu, Linze Li, Jiajun Chen, Yuan-Hao Yang, Yilong Zhou, Jia-Hua Zou, Xin-Biao Xu, Weiting Wang, Baile Chen, Haifeng Yu, Chang-Ling Zou, Luyan Sun
Optics
Controlling photothermal forces and backaction in nano-optomechanical resonators through strain engineering
Menno H. Jansen, Cauê M. Kersul and Ewold Verhagen
In micro- and nanoscale optomechanical systems, radiation pressure interactions are often complemented or impeded by photothermal forces arising from thermal strain induced by optical heating. We show that the sign and magnitude of the photothermal force can be engineered through deterministic nanoscale structural design, by considering the overlap of temperature and modal strain profiles. We demonstrate this capability experimentally in a specific system: a nanobeam zipper cavity by changing the geometry of its supporting tethers. A single design parameter, corresponding to a nanoscale geometry change, controls the magnitude of the photothermal backaction and even its sign. These insights will allow engineering the combined photothermal and radiation pressure forces in nano-optomechanical systems, such that backaction-induced linewidth variations are deterministically minimized if needed, or maximized for applications that require cooling or amplification at specific
laser detuning.
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Medical Physics
Equivariant Multiscale Learned Invertible Reconstruction for Cone Beam CT: From Simulated to Real Data
Nikita Moriakov, Efstratios Gavves, Jonathan H. Mason et al. (+3 more)
Cone Beam CT (CBCT) is an important imaging modality nowadays, however lower image quality of CBCT compared to more conventional Computed
Tomography (CT) remains a limiting factor in CBCT applications. Deep learning reconstruction methods are a promising alternative to classical analytical and iterative reconstruction methods, but applying such methods to CBCT is often difficult due to the lack of ground truth data,
memory limitations and the need for fast inference at clinically-relevant resolutions. In this work we propose LIRE++, an end-to-end rotationally-equivariant multiscale learned invertible primal-dual scheme for fast and
memory-efficient CBCT reconstruction.
Memory optimizations and multiscale reconstruction allow for fast training and inference, while rotational equivariance improves parameter efficiency. LIRE++ was trained on simulated projection data from a fast quasi-Monte Carlo CBCT projection simulator that we developed as well. Evaluated on synthetic data, LIRE++ gave an average improvement of 1 dB in Peak Signal-to-Noise Ratio over alternative deep learning baselines. On real clinical data, LIRE++ improved the average Mean Absolute Error between the reconstruction and the corresponding planning CT by 10 Hounsfield Units with respect to current proprietary state-of-the-art hybrid deep-learning/iterative method.
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All authors Nikita Moriakov, Efstratios Gavves, Jonathan H. Mason, Carmen Seller-Oria, Jonas Teuwen, Jan-Jakob Sonke
Data Analysis and Statistics · Cross-listed from q-bio.NC
Active inference and artificial reasoning
Karl Friston, Lancelot Da Costa, Alexander Tschantz et al. (+4 more)
This technical note considers the sampling of outcomes that provide the greatest amount of information about the structure of underlying world models. This generalisation furnishes a principled approach to structure learning under a plausible set of generative models or hypotheses. In active inference, policies - i.e., combinations of actions - are selected based on their expected free energy, which comprises expected information gain and value. Information gain corresponds to the KL divergence between predictive posteriors with, and without, the consequences of action. Posteriors over models can be evaluated quickly and efficiently using
Bayesian Model Reduction, based upon accumulated posterior beliefs about model parameters. The ensuing information gain can then be used to select actions that disambiguate among alternative models, in the spirit of optimal experimental design. We illustrate this kind of active selection or
reasoning using partially observed discrete models; namely, a 'three-ball' paradigm used previously to describe artificial insight and 'aha moments' via (synthetic) introspection or sleep. We focus on the sample efficiency afforded by seeking outcomes that resolve the greatest uncertainty about the world model, under which outcomes are generated.
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All authors Karl Friston, Lancelot Da Costa, Alexander Tschantz, Conor Heins, Christopher Buckley, Tim Verbelen, Thomas Parr
Plasma Physics
Coherent-field QED transitions based on coherent-state boundary conditions
Keita Seto
We develop a coherent-field formulation of
quantum electrodynamics (QED) based on coherent-state boundary conditions, in which
laser fields are represented by asymptotic coherent states rather than by prescribed classical background fields. Starting from coherent-state boundary conditions and the displacement-operator formalism, we construct operator and path-integral descriptions of transitions between distinct electromagnetic coherent states. This formulation provides a coherent-field extension of conventional background-field QED and incorporates the
quantum dynamics of the coherent field itself. The corresponding path-integral representation contains a functional integral over coherent-field histories in addition to the usual functional integral over
quantum fluctuations, thereby extending the conventional background-field description. The resulting path-integral representation naturally leads to an effective action for the stationary coherent-field configuration. The corresponding saddle-point condition yields an effective Maxwell equation containing contributions from
vacuum polarization,
photon fluctuations, and coherent-field fluctuations. In the limit where the latter two contributions vanish, the formalism reduces to the conventional Heisenberg-Euler description.
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Optics
Dual-comb spectroscopy for the characterization of laboratory flames
Bernat Frangi, Laura Monroy, Aldo Moreno-Oyervides et al. (+4 more)
Optical spectroscopy, in particular dual-comb (DC) spectroscopy, is a critical, non-invasive tool for combustion diagnostics, offering high precision and calibration-free advantages. However, its implementation remains challenging, especially in the mid-infrared region. This work presents the development of a robust DC spectroscopic system based on electro-optical (EO) frequency comb generators and difference frequency generation (DFG), specifically designed for the characterization of laboratory flames. Operating at a center wavelength of 3427.43 nm, the system utilizes a differential detection strategy to enable precise, calibration-free measurements of unburned methane ($\mathrm{CH_{4}}$) concentrations in a McKenna burner. The experimental results demonstrate an estimated detection limit of 1.1 ppm for a 1 m path length and effectively resolve spatial concentration gradients across the combustion region. Furthermore, the system's high temporal resolution allowed for the identification of dynamic combustion instabilities, including self-sustained pulsations and fuel leakage under fuel-lean conditions. These findings validate the proposed EO architecture as a flexible and highly sensitive tool for advanced flame characterization.
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All authors Bernat Frangi, Laura Monroy, Aldo Moreno-Oyervides, Oscar E. Bonilla-Manrique, Mariano Rubio-Rubio, Mario Sanchez-Sanz, Pedro Martín-Mateos
Optics
Non-Abelian gauge field optics in the time domain
Yucheng Lai, Yongliang Zhang and Kai Chang
Artificial gauge fields open up burgeoning opportunities for wave engineering in different disciplines. So far,previous works have mostly focused on synthesizing spatial gauge fields, where the pseudo-
magnetic fields lie at the heart of these phenomena. In this Letter, we generalize the paradigm of gauge field optics to the time domain by using time-varying media with rotating anisotropy. Dual to its spatial counterpart, the temporal gauge field induces a pseudo-electric field for optical pulses, leading to the
spin-dependent longitudinal shift and Zitterbewegung for both trajectory and frequency. In addition, we analyze the temporal non-Abelian interference effect induced by temporally bounded non-Abelian gauge field media, which results in the temporal
spin-precession and the temporal analogy of the non-Abelian Aharonov-Bohm effect. Our work not only fills the gap between synthetic gauge fields and time-varying physical systems, but also provides a fundamentally new approach for manipulating light with time-varying media.
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Chemical Physics
Hamiltonian-Informed Point Group Symmetry-Respecting Ansatz for Variational Quantum Eigensolver
Runhong He, Arapat Ablimit, Xin Hong et al. (+5 more)
Solving molecular energy levels via the Variational
Quantum Eigensolver (VQE)
algorithm represents one of the most promising applications for demonstrating practically meaningful
quantum advantage in the noisy intermediate-scale
quantum (NISQ) era. To strike a balance between ansatz complexity and computational stability in VQE calculations, we propose the HiUCCSD, a novel
symmetry-respecting ansatz engineered from the intrinsic information of the
Hamiltonian. We theoretically prove the effectiveness of HiUCCSD within the scope of Abelian point groups. Furthermore, we compare the performance of HiUCCSD and the established SymUCCSD via VQE and Adaptive Derivative-Assembled Pseudo-Trotter (ADAPT)-VQE numerical experiments on ten molecules with distinct point groups. The results show that HiUCCSD achieves equivalent performance to SymUCCSD for Abelian point group molecules, while avoiding the potential performance failure of SymUCCSD in the case of non-Abelian point group molecules. Across the studied molecular systems, HiUCCSD cuts the parameter count by 18%-83% for VQE and reduces the excitation operator pool size by 27%-84% for ADAPT-VQE, as compared with the UCCSD ansatz. With enhanced robustness and broader applicability, HiUCCSD offers a new ansatz option for advancing large-scale molecular VQE implementation.
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All authors Runhong He, Arapat Ablimit, Xin Hong, Qiaozhen Chai, Junyuan Zhou, Ji Guan, Guolong Cui, Shenggang Ying
Instrumentation and Detectors · Cross-listed from nucl-ex
Electron spectral shape of the third-forbidden $\beta$-decay of $^{87}$Rb measured using a Rb$_2$ZrCl$_6$ crystal scintillator
P. Belli, R. Bernabei, F. Cappella et al. (+12 more)
In recent years, interest in experimental studies of $\beta$-decay electron spectra – often referred to as $\beta$ spectra – has been growing. This is particularly true for $\beta$ transitions where the electron spectra are sensitive to the effective value of the weak axial coupling, $g_{\rm A}$. Such measurements serve as important
benchmarks for
nuclear physics calculations and can also be used to characterize background in astroparticle physics experiments. In this work, a dedicated experiment has been carried out to investigate the spectral shape of the third-forbidden $^{87}$Rb $\beta$-decays, with the goal of estimating the effective $g_{\rm A}$ value for this transition and of deriving the T$_{1/2}$ value. This was done by comparing the experimental spectral shape with the estimates from various phenomenological models. The $^{87}$Rb source was embedded directly within the detector material of a new Rb$_2$ZrCl$_6$
crystal scintillator; the data taking was performed deep underground at Gran Sasso National Laboratory. The obtained experimental half-life value for the studied process is T$_{1/2} = 5.08(13) \times$ 10$^{10}$ yr; while a $g_{\rm A}$ value in the range 0.4 to 0.6 is obtained when accounting for uncertainties and depending on the model adopted as discussed in detail in the text.
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All authors P. Belli, R. Bernabei, F. Cappella, V. Caracciolo, R. Cerulli, A. Incicchitti, A. Leoncini, V. Merlo, S.S. Nagorny, V.V. Nahorna, S. Nisi, P. Wang, J. Suhonen, M. Ramalho, J. Kostensalo
Fluid Dynamics
Rayleigh-Plateau instability of an elasto-viscoplastic filament
James D. Shemilt and Neil J. Balmforth
A slender-thread model is used to explore the Rayleigh-Plateau instability of a filament of elasto-viscoplastic fluid. Without elasticity, a finite yield stress suppresses any linear instability for a filament of constant radius. Including sub-yield elastic deformation permits an elastic Rayleigh-Plateau instability above a critical Deborah number. If stresses over the thinner sections of the thread breach the yield threshold, viscoplastic deformations then drive the filament towards pinch-off. The thread consequently evolves to a beads-on-a-string structure. The elasto-plastic anatomy of the beads is explored and categorized.
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Optics
Generation of hallow vector beam by high-order cylindrical vector beams
Brijesh Kumar Mishra and Brijesh Kumar Singh
We propose a method for generating hollow beams using higher-order cylindrical vector modes of the form R-TEMpl, where the radial index p is varied from 1 to 3 while the azimuthal index is fixed at l = 1. It is found that this scheme performs identically under incident illumination with either radial or azimuthal polarization. For this purpose, we use a focusing lens in combination with a diffractive optical element formed by a computer-generated hologram containing multiple alternate opaque and transparent regions. Based on vector diffraction theory, our analysis shows that the multi-zone amplitude mask redistributes the beam energy, thereby leading to the formation of a hollow beam. The proposed method provides control over the beam width which maintains a uniform dark core size after focusing through the various NA lens across all the higher order modes. Further the width of high intensity ring can be tuned by varying the NA of the focusing lens. This study shows that the proposed method is well suited for trapping particles or atoms while avoiding exposure to high central intensity, enabling improved contrast and resolution, facilitating ring-shaped ablation or heating, guiding atoms through dark regions to minimize thermal effects, and supporting information encoding using orbital angular momentum and other advanced optical applications.
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Atomic Physics
Acetaldehyde as a molecule for testing variations of electron-to-proton mass ratio
J. S. Vorotyntseva, S. A. Levshakov and M. G. Kozlov
We present the
quantum-mechanical calculations of the dimensionless sensitivity coefficients Q to small changes in the fundamental physical constant mu = m_e/m_p - the electron-to-
proton mass ratio - for a number of low-frequency (1-50 GHz) transitions of the acetaldehyde (CH3CHO) molecule. The calculations show that Q varies in the range from 0.62 to 3.61. An example of the practical use of the CH3CHO and CH3OH lines tracing the same regions in three molecular clouds, located at large galactocentric distances (D_GC ~ 8 kpc) is considered. This results in a limit on the mu variations of Delta mu/mu = (0.1 +/- 0.4)*10^(-7) which is in line with previously obtained most stringent upper limits on changes in mu based on other molecules and methods. The limit obtained restricts hypothetical violations of the Einstein principle of the local position invariance at the level of 4*10^(-8) in the
Galactic disk at large galactocentric distances.
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Fluid Dynamics · Cross-listed from cond-mat.soft
Wave-Like Statistics from Classical Active Particles with Internal Degrees Of Freedom
Rahil N. Valani
Wave-like spatial statistics in walking-droplet systems are often associated with wave-mediated interactions and wave-
memory effects. Here we explore how similar statistical structure can arise from the low-dimensional nonlinear dynamics of an inertial active particle with internal degrees of freedom. In this framework, steady propulsion corresponds to internal-state fixed points whose spiral or transiently chaotic relaxation organizes oscillatory ensemble densities. Local perturbations then generate wave-like statistics in both open and closed geometries, suggesting that wave-like ensemble behavior may emerge more generally from internal-state attractor dynamics in inertial active matter.
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Atmospheric and Oceanic Physics · Cross-listed from astro-ph.EP
Quantum scattering of hot H/D on CO$_2$: Cross sections and rate coefficients for planetary atmospheres and their evolution
Cheikh T. Bop and Marko Gacesa
Collisions between hot hydrogen atoms and CO$_2$ play a central role in energy transfer and atmospheric escape in CO$_2$-rich planetary atmospheres. We present
quantum mechanical $j_z$-conserving coupled-states calculations of state-resolved cross sections for H/D–CO$_2$ collisions at energies up to 5~eV, benchmarked to within 7% of close-coupling results. Scattering is strongly forward-peaked, yielding momentum-transfer cross sections substantially smaller than commonly assumed: mass-scaling from O/C–CO$_2$ systems overestimates H–CO$_2$ total cross sections by factors of 30–45, while existing empirical fits underestimate the low-energy regime by up to $\sim$45%. Isotopic substitution (H/D) produces energy-dependent differences of up to 35% at $E<0.1$~eV, invalidating uniform scaling approaches for D/H fractionation. Maxwellian-averaged rate coefficients derived from our cross sections are significantly smaller than mass-scaled values, implying reduced H–CO$_2$ energy transfer efficiency. In atmospheric escape modelling, these revisions can shift Martian exobase altitudes by 10–20~km, leading to order-unity changes in thermal escape rates, and have implications for hydrogen loss in early CO$_2$-dominated planetary atmospheres. Our results provide essential
quantum-mechanical inputs for revisiting atmospheric
evolution scenarios on Mars, early Earth, and CO$_2$-rich
exoplanets.
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Fluid Dynamics
Passive scalar cascade in the intermediate layer of turbulent channel flow for $Pr\leq 1$
Emanuele Gallorini, Shingo Motoki, Genta Kawahara et al. (+1 more)
Similarities and differences between Kolmogorov scale-by-scale
equilibria/non-
equilibria for velocity and scalar fields are investigated in the intermediate layer of a fully developed turbulent channel flow with a passive scalar/temperature field driven by a uniform heat source. The analysis is based on intermediate asymptotics and direct numerical simulations at different Prandtl numbers lower than unity. Similarly to what happens to the velocity fluctuations, for the fluctuating scalar field Kolmogorov scale-by-scale
equilibrium is achieved asymptotically around a length scale $r_{min}$, which is located below the inertial range. The lengthscale $r_{min}$ and the ratio between the inter-scale transfer and dissipation rates at $r_{min}$ vary following power laws of the Prandtl number, with exponents determined by matched asymptotics based on the hypothesis of homogeneous two-point physics in non-homogeneous
turbulence. The interscale transfer rates of turbulent kinetic energy and passive scalar variance are globally similar but show evident differences when their aligned/anti-aligned contributions are considered.
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All authors Emanuele Gallorini, Shingo Motoki, Genta Kawahara, Christos Vassilicos
Optics · Cross-listed from cs.CV
A Large-Depth-Range Layer-Based Hologram Dataset for Machine Learning-Based 3D Computer-Generated Holography
Jaehong Lee, You Chan No, YoungWoo Kim et al. (+1 more)
Machine learning-based computer-generated holography (ML-CGH) has advanced rapidly in recent years, yet progress is constrained by the limited availability of high-quality, large-scale hologram
datasets. To address this, we present KOREATECH-CGH, a publicly available
dataset comprising 6,000 pairs of RGB-D images and complex holograms across resolutions ranging from 256*256 to 2048*2048, with depth ranges extending to the theoretical limits of the angular spectrum method for wide 3D scene coverage. To improve hologram quality at large depth ranges, we introduce amplitude projection, a post-processing technique that replaces amplitude components of hologram wavefields at each depth layer while preserving phase. This approach enhances reconstruction fidelity, achieving 27.01 dB PSNR and 0.87 SSIM, surpassing a recent optimized silhouette-masking layer-based method by 2.03 dB and 0.04 SSIM, respectively. We further validate the utility of KOREATECH-CGH through experiments on hologram generation and super-resolution using state-of-the-art ML models, confirming its applicability for training and evaluating next-generation ML-CGH systems.
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All authors Jaehong Lee, You Chan No, YoungWoo Kim, Duksu Kim
Optics
Robust photon blockade with hybrid molecular optomechanics
Jian Tang, Baijun Li, Bin Yin et al. (+4 more)
Molecular cavity optomechanical systems, featuring ultrahigh vibrational frequencies and strong light-matter interactions, hold significant promise for advancing applications in
quantum science and technology. Specifically, by introducing metallic nanoparticles into microcavities, hybrid molecular cavity optomechanical systems can further enhance optical quality factors and system tunabilities, which enables scalable and controllable
quantum platforms. In this study, we propose how to realize robust
photon blockade, i.e., strong
photon antibunching with arbitrary detuning conditions, by combining degenerate optical parametric amplification with a hybrid molecular cavity optomechanical system. More interesting, we find near-perfect optomechanical
photon blockade at room temperature, which is robust against temperature and optical dissipation. In addition, our approach can release the strict condition of high temporal resolution by combining features of conventional and unconventional
photon blockade. Our approach offers a feasible route to study intriguing
quantum effects in hybrid molecular cavity optomechanical systems, and holds promise for applications in nonclassical state engineering,
quantum sensing, and photonic precision measurements.
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All authors Jian Tang, Baijun Li, Bin Yin, Tian-Xiang Lu, Ran Huang, Franco Nori, Hui Jing
Applied Physics · Cross-listed from quant-ph
Quantum Homotopy Algorithm for Solving Nonlinear PDEs and Flow Problems
Sachin S. Bharadwaj, Balasubramanya Nadiga, Stephan Eidenbenz et al. (+1 more)
Quantum algorithms to integrate nonlinear PDEs governing flow problems are challenging to discover but critical to enhancing the practical usefulness of
quantum computing. We present a near-optimal, robust, and end-to-end
quantum algorithm to solve time-dependent, dissipative, nonlinear PDEs. We embed the PDEs in a truncated, high-dimensional linear space on the basis of
quantum homotopy analysis. The linearized system is discretized and integrated using finite-difference methods with a compact
quantum algorithm. The present approach can adapt its input to the nature of nonlinearity and underlying physics. The complexity estimates improve existing approaches in terms of the time-marching system size, simulation time, accuracy parameters, and post-selection parameters. We provide a general
embedding strategy, bounds on stability criteria, accuracy, gate counts, and query complexity. A physically motivated measure of nonlinearity is connected to a parameter similar to the flow Reynolds number $Re_{\textrm{H}}$, whose inverse marks the allowed integration window, for given accuracy and complexity. We illustrate the
embedding scheme with numerical simulations of Burgers, Fisher–KPP, damped Kuramoto–Sivashinsky, and real Ginzburg–Landau/Allen–Cahn equations. Together, these examples encompass cubic nonlinearity and saturation, quadratic transport, and fourth-order dissipative stiffness. This work shows the potential of hybrid
quantum algorithms for simulating nonlinear problems on near-term and fault-tolerant devices.
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All authors Sachin S. Bharadwaj, Balasubramanya Nadiga, Stephan Eidenbenz, Katepalli R. Sreenivasan
Chemical Physics
Formal O(N3) scaling GW calculations by block tensor decomposition for large molecule systems
Yueyang Zhang, Wei Wu and Peifeng Su
Within the framework of many-body perturbation theory based on Green's functions, the $GW$ approximation has emerged as a pivotal method for computing quasiparticle energies and excitation spectra. However, its high computational cost and steep scaling present significant challenges for applications to large molecular systems. In this work, we extend the block tensor decomposition (BTD)
algorithm, recently developed in our previous work [J. Chem. Phys. 163, 174109 (2025)] for low-rank tensor compression, to enable a formally $O(N^3)$-scaling $GW$
algorithm. By integrating BTD with an imaginary-time $GW$ formalism and introducing a real space screening strategy for the polarizability, we achieve an observed scaling of approximately $O(N^2)$ in test systems. Key parameters of the
algorithm are optimized on the S66
dataset using the JADE
algorithm, ensuring a balanced compromise between accuracy and efficiency. Our BTD-based random phase approximation also exhibits $O(N^2)$ scaling, and
eigenvalue-self-consistent $GW$ calculations become feasible for systems with over 3000 basis functions. This work establishes BTD as an efficient and scalable approach for large-scale $GW$ calculations in molecular systems.
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Optics
Fundamental Phase Noise in Thin Film Lithium Niobate Resonators
Ran Yin, Yue Yu, Chunho Lee et al. (+3 more)
Fundamental phase noise in thin-film lithium niobate (TFLN) photonic integrated
circuits is governed by thermal-charge-carrier-refractive (TCCR) dynamics arising from thermally driven carrier fluctuations. In contrast to the predominantly thermorefractive noise in silicon photonic platforms, TCCR noise represents a distinct mechanism that becomes critical for applications requiring high frequency stability and phase coherence, including optomechanical sensing, low-phase-noise microwave synthesis, and on-chip
quantum squeezing. A quantitative understanding of the deterministic parameters that control TCCR noise is therefore essential for engineering the next generation of low-noise TFLN photonic systems. Here, we identify two dominant contributors to the TCCR noise in TFLN microresonators: material anisotropy and surface states. Material anisotropy results in increased noise for extraordinarily polarized optical modes and leads to a geometry dependent phase noise. Surface-state effects manifest as increased noise in higher-order transverse modes as well as more than 120-fold higher noise in suspended microresonators. Finally, we demonstrate that post-fabrication annealing – widely used to reduce defect densities and recover
crystal quality – suppresses frequency noise by a factor of 8.2 in cladded microresonators. Together, these results establish a practical pathway for noise engineering in TFLN integrated photonic devices and accelerate their deployment in next-generation precision photonic systems.
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All authors Ran Yin, Yue Yu, Chunho Lee, Ian Christen, Zaijun Chen, Mengjie Yu
Optics
Magneto-optical Skyrmion for manipulation of arbitrary light polarization
Xinghong Chen, Xingxiang Wang, Guanjie Zhang et al. (+4 more)
Dynamic manipulation of arbitrary light polarization is of fundamental importance for versatile optical functionalities, yet realizing such full-Poincaré-sphere control within compact nanophotonic architectures remains a formidable challenge. Here, we theoretically propose and numerically demonstrate a magneto-optical skyrmion platform enabling full polarization control of cavity eigenmodes. We reveal the correspondence between the near-field wavefunctions of degenerate dipoles and far-field polarization. By applying multidirectional
magnetic fields to magneto-optical photonic
crystals, we achieve any complex superposition of orthogonal eigenmodes, thereby realizing arbitrary far-field polarization. This mapping manifests as a skyrmion with a topological charge of 2, guaranteeing coverage of the entire Poincaré sphere. Our theoretical model shows excellent agreement with full-wave simulations. Furthermore, we realize bound states in the continuum (BICs) with dynamically tunable polarization textures and demonstrate high-performance polarization-selective emission and transmission. This work establishes a topological paradigm for precise polarization shaping, offering new avenues for advanced optical communication and sensing.
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All authors Xinghong Chen, Xingxiang Wang, Guanjie Zhang, Xiao Hu, Wei Tao, Tomohiro Amemiya, Yifei Mao