Quantum Physics
Entanglement engineering in magnomechanical system via cross-Kerr interaction and mechanical parametric amplification
E. Kongkui Berinyuy, P. Djorwé, A. N. Al-Ahmadi et al. (+2 more)
Quantum entanglement in cavity magnomechanical system has a wide range of applications in modern
quantum technologies. In this work, we propose a theoretical scheme to generate and enhance
quantum entanglement through cross-Kerr nonlinearity and mechanical parametric amplification (MPA) in a magnomechanical system. Our system is made of a magnonic mode that is simultaneously driving the acoustic phononic and the center-of-mass motion (CMM)
phonon in a yttrium iron garnet sphere. The acoustic mode and the center-of-mass mechanical (CMM) mode are weakly coupled via the
phonon hopping rate $J_m$. Moreover, the magnonic and phononic modes interact through cross-Kerr interaction, while the phononic mode is additionally driven via a Mechanical Parametric Amplification (MPA). Without the mechanical coupling ($J_m = 0$) and the MPA, the generation of
entanglement among the subsystems requires a relatively strong effective cross-Kerr coupling. However, when
phonon hopping and MPA are accounted,
quantum entanglement can be generated even for weak values of the cross-Kerr coupling strength, revealing the key role of these interactions in the engineering of
quantum correlations in our proposal. Furthermore, the related purity of the generated entangled states remains high for the same parameter's regime, revealing that the generated
quantum entanglement is established without significantly increasing the mixing of the involved states in the system. Our work suggests how robust and stable
quantum correlations can be engineered in magnomechanical structures based on nonlinear interactions. These results are useful for modern
quantum applications including
quantum information processing,
quantum communication, and
quantum computational tasks.
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All authors E. Kongkui Berinyuy, P. Djorwé, A. N. Al-Ahmadi, H. Ardah, A.-H. Abdel-Aty
Optics · Cross-listed from cs.CV
OSOG: A Differentiable, Physics-Informed Synthetic Data Engine for Micro-Optical Environments
Caio Silva
Deep learning in computational microscopy is severely constrained by the scarcity of densely annotated
datasets. While synthetic data generation has bridged this gap in macroscopic computer
vision, traditional graphics engines rely on
geometric ray-tracing, failing to capture the micro-optical phenomena required for microscopy. Conversely, while wave-optics formulations exist, rendering them computationally tractable at the scale required for deep learning remains a massive systems challenge. To address this, we introduce the Optical Synthetic Object Generator (OSOG), a high-performance, fully differentiable forward-modeling engine. Drawing on established physical models of diffraction and phase retardation, OSOG maps continuous Optical Path Difference (OPD) calculations into a highly optimized, PyTorch-native Structure-of-Arrays (SoA) architecture. We validate this computational framework across three axes: First, object detection models (YOLOv11-OBB) trained purely on OSOG-generated data achieve robust zero-shot transfer to real-world highly occluded Lysozyme micrographs. Second, we introduce DiffOSOG, demonstrating that the engine's end-to-end differentiability allows for the exact recovery of continuous optical parameters via curriculum-guided inverse rendering. Finally, OSOG bypasses the $\mathcal{O}(N)$ bottlenecks of sequential ray-tracing, demonstrating sub-linear scaling by synthesizing 40,000 complex wave-optic particles in under 50 milliseconds (\>20 FPS). By providing a fast, scalable, and physically grounded tensor pipeline, OSOG enables true real-time, on-the-fly
dataset generation.
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High Energy Physics (Phenomenology)
Theoretical consistency and phenomenology of supercooled cosmological phase transitions
Maciej Kierkla
This dissertation investigates a supercooled phase transition (PT) in the early Universe. Using high-temperature dimensional reduction (DR), we compute the NLO thermal bubble nucleation rate. By explicitly evaluating fluctuation determinants, we provide a state-of-the-art description of thermal bubble nucleation. As a case study, we consider the SU(2)cSM, an extension of the conformal Standard Model with an additional SU(2)$_X$ gauge sector and scalar field that acquires a vev through radiative
symmetry breaking. This
symmetry breaking proceeds via a supercooled first-order phase transition. The first part of the thesis introduces the theoretical framework, including effective actions, RG improvements, finite-temperature
quantum field theory, effective field theory techniques, and thermal bubble nucleation. The second part applies these methods to the SU(2)cSM. We establish a consistent power-counting scheme, construct the leading-order effective potential, analyse
symmetry breaking and parameter space, derive an RG-improved potential, and incorporate thermal corrections. We then apply high-temperature DR to a classically scale-invariant model for the first time, derive the corresponding three-dimensional EFT, and compute the NLO nucleation rate. A detailed numerical evaluation of fluctuation determinants enables a comparison of different approximation schemes and their limitations. Finally, we present the phenomenological implications. We determine phase transition parameters, perform parameter scans, and predict the resulting gravitational wave signals. We find that the supercooled phase transition in the SU(2)cSM produces a strong signal detectable by LISA throughout the parameter space considered, making the model experimentally testable. We also demonstrate that higher-order corrections can significantly affect both phase transition dynamics and gravitational wave predictions.
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Quantum Physics
Collective enhancement in sideband cooling of ion crystals
Ivan Vybornyi, Artem Zhdanov, Matthias Bock et al. (+4 more)
Low-
entropy motional states of ion Coulomb
crystals are an essential prerequisite for a plethora of applications and are typically prepared by
laser cooling. As larger
crystals are operated in the
quantum regime, it remains unclear, and has recently become debated, whether increasing the ion number can be beneficial for cooling. Here, we investigate theoretically and experimentally many-ion sideband cooling and the role of collective effects in different
spin-motion coupling regimes. For weak coupling, the many-body effects are insignificant. In the strong-coupling regime, however, the
spin and motional subsystems undergo a coherent state swap, enabling cooling by a suitably timed
laser pulse. Using planar Coulomb
crystals with up to 91 ions, we demonstrate that the residual mean
phonon occupation after one such pulse scales as $1/N^2$ with the number of ions. By iterating the pulses, we measure mean
phonon occupations $<2\cdot10^{-4}$. For large
crystals in the coherent regime, we further show that the
spin-motion dynamics becomes largely independent of the initial
phonon statistics. Through
spin measurements, the state-swap mechanism can be utilized to probe the
phonon distribution in the mode.
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All authors Ivan Vybornyi, Artem Zhdanov, Matthias Bock, Leo Walz, Nele Griesbach, Klemens Hammerer, Christian F. Roos
Quantum Physics
Noise robustness of three outcome Bell certified quantum randomness
Raffaele D'Avino, Ignacio Perito, Piotr Mironowicz et al. (+2 more)
We investigate device-independent certification of global randomness based on Bell inequality violations in bipartite scenarios with three outcomes per party. Our goal is to determine whether multi-outcome measurements allow one to surpass the amount of randomness achievable with binary outputs in realistic scenarios. We begin by analyzing several known Bell expressions and evaluating their robustness against noise for randomness certification. We then introduce a systematic method for generating new Bell expressions within structured families and perform a large-scale numerical study. We find that a substantial number of inequalities certify significant amounts of min-
entropy. In particular, we identify simple inequalities that achieve near-maximal global randomness while involving a reduced number of measurement settings, thus improving the balance between certified randomness and number of inputs. Moreover, the vast majority of nontrivial certificates exhibit robustness against realistic noise, maintaining positive certified randomness away from the ideal regime. These results demonstrate that strong device-independent randomness expansion in multi-outcome scenarios is not restricted to carefully engineered inequalities, but arises generically within suitably constructed families of Bell expressions.
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All authors Raffaele D'Avino, Ignacio Perito, Piotr Mironowicz, Antonio Acín, Remigiusz Augusiak
Biological Physics
Computationally guided modifications of CviUPO to improve catalytic activity
Hanna-Friederike Poggemann, Tim Dirks, Timo Jacob et al. (+1 more)
Unspecific peroxygenases (UPOs) are promising biocatalysts that selectively oxyfunctionalize saturated hydrocarbons using only hydrogen peroxide as a co-substrate. Peroxide-induced enzyme inactivation makes targeted enzyme engineering essential to mitigate this effect and also enhance catalytic performance. To meet this need, systematic approaches are used, including extensive database studies for rational enzyme design, as well as computational enzyme engineering. In this study, we followed the latter strategy and explored the possibility for computationally-guided modification of UPOs. Specifically, our focus was on uncovering the influence of active site amino acids on the catalytic activity of the enzyme CviUPO. Two mutations were introduced close to the active center, and the changes in the energy barriers leading to the activated complex were investigated in detail by
Quantum Mechanics/Molecular Mechanics Nudged Elastic Band simulations. Our studies revealed that a change of the glutamic acid, assisting the catalytic cycle, by the shorter aspartic acid, leads to an increased reaction barrier, probably decreasing the catalytic activity of the enzyme. Exchanging the heme-anchoring cysteine group by a histidine exhibited promising behavior as the energy barriers decreased significantly. However, it is possible that the histidine modification also alters the reaction behavior of the peroxygenase, turning it into a peroxidase, an aspect that so far could not be confirmed beyond doubt. Simulations alone cannot conclusively determine whether substrate specificity and reactivity are maintained in the modifications tested. Nevertheless, our results highlight the importance of
spin states and active pocket hydration for the catalytic reaction and demonstrate why a synergistic approach of theoretical predictions and experimental verifications is required for efficient enzyme engineering.
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All authors Hanna-Friederike Poggemann, Tim Dirks, Timo Jacob, Christoph Jung
Quantum Physics
Maximal global device-independent randomness from projective measurements in every dimension
Máté Farkas, Piotr Mironowicz and Remigiusz Augusiak
Device-independent random number generation (DIQRNG) is the most secure form of generating private randomness using
quantum physical processes. Its strength lies in producing numbers that are impossible to predict by any eavesdropper restricted by the laws of
quantum theory. Moreover, security is proven solely from observed measurement statistics, without the need to characterise or trust the devices used in random number generation. Implementing DIQRNG is, however, costly, as it requires high-quality entangled systems. It is therefore important to make the best use of available resources. In this work, we show that using projective measurements – which are most readily implementable experimentally – one can certify $2\log(d)$ bits of device-independent randomness from a bipartite system of local dimension $d$ for every $d \ge 2$, thus reaching the theoretically maximum possible rate of DIQRNG. We provide explicit protocols reaching $2\log(d)$ bits based on mutually unbiased bases. Furthermore, we compute numerical bounds on the rate for the case of imperfect implementations, showing that our protocols are robust to experimental noise.
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Quantum Physics
Bell inequalities tailored to optimal global randomness certification
Ignacio Perito, Raffaele D'Avino, Michał Jung et al. (+3 more)
We present two novel families of bipartite Bell inequalities designed to achieve optimal global randomness certification for an arbitrary number of outputs $d$. We first use
symmetry arguments to argue that their maximal
quantum violations certify $2\log d$ random bits. For the first family, we construct a
quantum realization using $d\times d$ maximally entangled states which provides a
quantum violation that we
conjecture to be optimal for any $d$. It is then numerically shown that the obtained
quantum violation certifies optimal global randomness, up to numerical precision, for $d=3,4$. For the second family, we provide the optimal
quantum violation and its
quantum realization for any $d$, again using $d\times d$ maximally entangled states and projective measurements over at least two unbiased bases on one of the parties. We self-test this realization for $d=3$, which implies the optimal certification of two fully random trits.
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All authors Ignacio Perito, Raffaele D'Avino, Michał Jung, Piotr Mironowicz, Antonio Acín, Remigiusz Augusiak
Astrophysics of Galaxies
Extended [CII] gas emission in and around a massive quiescent galaxy at z=7.3
F. Valentino, A. Pensabene, A. Weibel et al. (+16 more)
We report the discovery of [CII] 158 micron emission in and around the most distant known massive quiescent
galaxy RUBIES-UDS-QG-z7 at z = 7.27. Observed with ALMA in band 6, the [CII] line independently confirms the spectroscopic
redshift from JWST/NIRSpec spectra at low and medium resolution. The emission extends over an effective radius R_eff,[CII] = 8 +/- 3 kpc, well beyond the compact
stellar body traced by JWST/NIRCam (R_eff = 209 (+33/-24) pc), with a significant fraction of approximately 70% of the flux arising from a circumgalactic
halo. No
dust continuum is detected at rest-frame ~160 micron, setting an upper limit on the infrared luminosity of L_IR < 1.4 x 10^11 Lsun, overall consistent with expectations from rest-frame UV to near-infrared SED modeling under energy balance. Converting the
galaxy-scale [CII] emission into cold gas mass, we find log(M_mol/Msun) = 9.53 (+0.32/-0.31) and log(M_HI/Msun) = 9.46-10.34, depending on the assumed calibration and
metallicity. Despite being approximately 10x more gas-poor than typical
star-forming
galaxies at fixed
redshift,
stellar mass, and [CII] to gas mass conversion, RUBIES-UDS-QG-z7 retains a substantial cold gas reservoir with fractions f_gas >~ 20% and long depletion timescales across most assumptions. The extended [CII]
halo carries approximately twice as much gas as the
galaxy alone and shows a blueshifted velocity offset consistent with the tentative gas
outflow detected in MgII absorption in previous work, suggesting a past episode of AGN-driven gas expulsion possibly linked to the suppression of
star formation. The presence of a large gas reservoir in and around a massive quiescent
galaxy just 700 Myr after the Big Bang implies that whatever mechanism is suppressing
star formation must be remarkably effective at maintaining a low
star formation efficiency on ~100 Myr timescales, even in the presence of abundant fuel.
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All authors F. Valentino, A. Pensabene, A. Weibel, A. de Graaff, D. J. Setton, P. Oesch, G. Brammer, W. M. Baker, R. Bezanson, J. E. Greene, K. E. Heintz, K. Ito, M. Lee, J. Leja, J. Matthee, B. Wang, K. E. Whitaker, C. C. Williams, P. Zhu
Quantum Physics
Quantum Beam-Splitter Cooling and Thermometry in Large Trapped-Ion Crystals
Kirthik Rajakumar, Ansh Das, Abhinay Pandey et al. (+1 more)
We propose and characterize a protocol for rapid near-ground state cooling of the center-of-mass (c.m.) mode of a large trapped ion
crystal. When the initial mean thermal occupation of the mode $\bar{n}_i$ is small compared to the number of ions $N$ ($\bar{n}_i \ll N$), a red sideband drive implements a beam-splitter type state exchange (SWAP operation) between the mode and the collective
spin of the $N$ ions, with the latter effectively serving as a
quantum harmonic oscillator. Subsequently, a reset of the
spins removes the
entropy, leading to near-ground state cooling of the c.m. mode. We term this protocol as
quantum beam-splitter cooling (QBSC). We analyze the impact of several practical imperfections on the final temperature achievable under QBSC, including finite ion number, off-resonant carrier and blue-sideband contributions, the sideband drives arising from spectator modes, and spatially inhomogeneous driving across the
crystal. We outline practical strategies to eliminate the carrier drive. We extend our analysis to multiple cycles of QBSC and also generalize the analysis to demonstrate the cooling of non-c.m. modes using this protocol. Furthermore, we show that measuring the population statistics of the ions at the end of the SWAP operation can enable near-optimal
quantum beam-splitter thermometry (QBST), with the classical Fisher information approaching the
quantum Fisher information of a thermal state. We discuss the connection of QBSC with continuous sideband cooling and compare QBST with a recently proposed rapid adiabatic passage-based thermometry scheme. Our work constitutes an example of harnessing many-body effects to open new routes to
laser cooling and thermometry in large trapped ion
crystals.
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All authors Kirthik Rajakumar, Ansh Das, Abhinay Pandey, Athreya Shankar
Quantum Physics
Efficient Verification of Entangled Measurements with Local States
Kun Wang and Masahito Hayashi
We develop a framework for
quantum measurement verification (QMV) using only local state preparations. For locally transitive and irreducible projective measurements, we prove that
symmetry reduces locality constrained QMV to
quantum state verification of a single basis state, thereby reducing protocol design to the optimization of homogeneous verification operators. We apply the framework to generalized Bell measurements, single-parameter measurements on two
qubits, elegant joint measurements, and stabilizer state induced measurements, and derive explicit local protocols together with closed form verification operators, success probabilities, and sample complexities. We further show that homogeneous QMV protocols can estimate measurement fidelity directly from observed passing frequencies.
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Instrumentation and Detectors
Enhanced electron-beam lithography to reduce the frequency scatter of 200-400 GHz superconducting microstrip resonators for on-chip filterbank spectrometers
L. G. G. Olde Scholtenhuis, D. J. Thoen, J. J. A. Baselmans et al. (+4 more)
Integrated superconducting spectrometers (ISSs) provide the instantaneous bandwidth, sensitivity, and scalable architecture for large-scale spectroscopic surveys in submillimeter-wave astronomy and cosmology. However, the accuracy with which the resonant frequencies of superconducting microstrip band pass filters can be spaced, has limited the spectral resolution for these spectrometers with continuous spectral coverage to $\frac{F}{\Delta F} < 500$. The origin of this frequency scatter has been largely unknown. In this work, we demonstrate a four-fold improvement in the frequency spacing of superconducting microstrip resonators by optimizing electron-beam lithography. We find that reducing the beam step size (BSS) on the nanometer scale reduces the random frequency scatter, and that avoiding main-field stitching across filter patterns can eliminate a systematic frequency shift between groups of resonators, indicating the different origins of these two modes of frequency deviation. These findings demonstrate that nanometer-scale control of lithographic processes is imperative for the realization of the next-generation integrated superconducting spectrometers with higher spectral resolution.
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All authors L. G. G. Olde Scholtenhuis, D. J. Thoen, J. J. A. Baselmans, K. Karatsu, L. H. Martin, S. Vollebregt, A. Endo
Optics
Mitigating Outages in a 4.6-km FSO Link via Mode-Diverse Reception: An Experimentally Validated Digital Twin Approach
Jonas Krimmer, Vincent van Vliet, Menno van den Hout et al. (+3 more)
Terrestrial coherent FSO requires mitigating
turbulence-induced coupling losses. We experimentally validate a "Digital Twin" channel model against fading statistics from a 4.6-km link. Combining long-term scintillometer data with mode-diverse receiver simulations, we demonstrate that a 6-mode receiver reduces
turbulence-induced outage probabilities to 2.02e-5.
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All authors Jonas Krimmer, Vincent van Vliet, Menno van den Hout, Eduward Tangdiongga, Chigo Okonkwo, Sebastian Randel
Medical Physics
MORSE-PI – Flexible and artefact-free image reconstruction for structural and functional QSM and other phase-critical imaging applications
Barbara Dymerska, Oliver Josephs, Benjamin James et al. (+3 more)
Phase imaging applications such as QSM are highly sensitive to noise amplifications, phase singularities, and other artefacts, particularly in challenging scenarios such as ultra-high field (7T), under-sampled or single-echo acquisitions. We present a novel image reconstruction method, MORSE-PI, designed to produce high-SNR, artefact-free, and singularity-free phase images for both structural and functional phase-based
brain imaging. MORSE-PI extends our previous approach, MORSE, by introducing a Virtual Reference Coil (VRC). The VRC is constructed as a linear combination of coil sensitivity maps, with correlations enhanced between coil elements using the noise covariance
matrix. Such a VRC ensures robust signal support across the entire
brain and is used to correct phase offsets in the MORSE-derived coil sensitivity estimates, resulting in artefact-free, high SNR phase. Compared to GRAPPA with ASPIRE phase correction, MORSE-PI demonstrates greater robustness to artefacts such as noise amplification and aliasing, and shows improved reproducibility in structural imaging at both 3T and 7T. Unlike ESPIRiT and GRAPPA combined with adaptive coil combination methods, MORSE-PI yields singularity-free phase maps. MORSE-PI enables high-SNR reconstructions even for the most challenging scenarios, such as single-echo EPI at 7T. Its efficient, containerised implementation using the Gadgetron framework supports deployment on the MRI scanner console during measurements. MORSE-PI offers a flexible and computationally efficient solution for generating high-SNR, artefact- and singularity-free phase images in both single- and multi-echo GRE and EPI acquisitions. This makes it particularly well-suited for structural and functional QSM, as well as other phase-based MRI applications. Its robustness and rapid computational time facilitate efficient deployment on scanners across field strengths.
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All authors Barbara Dymerska, Oliver Josephs, Benjamin James, Vahid Malekian, Nadine N. Graedel, Martina F. Callaghan
Astrophysics of Galaxies
All-sky modeling of Galactic emission at radio and microwave frequencies
Gabriel A. Hoerning, Clive Dickinson, Stuart E. Harper et al. (+13 more)
We present a new all-sky model of low-frequency diffuse
Galactic emission in the regime where synchrotron, free-free, and spinning
dust dominate. The model extends the Planck 2015 diffuse component-separation analysis by incorporating recent
radio and microwave surveys. We fit 35 full- and partial-sky maps at 1 degree resolution, including S-PASS at 2.30 GHz, C-BASS at 4.76 GHz, and QUIJOTE at 10-20 GHz, together with reprocessed WMAP and Planck LFI data from the Cosmoglobe collaboration and Planck HFI channels. Using a
Bayesian parametric approach with Commander, we derive spatially varying amplitude and spectral parameter maps for the dominant low-frequency foreground components in total intensity. The main products are a full-sky synchrotron amplitude and spectral-index solution, an all-sky characterization of spinning
dust emission with a single-component log-normal spectral model, and a reconstructed all-sky total-intensity map at 4.76 GHz tracing diffuse synchrotron emission with reduced systematics relative to Haslam 408 MHz. The revised low-frequency anchoring increases the recovered synchrotron amplitude: at 4.76 GHz, it is approximately a factor of two higher than the Planck 2015 prediction. The model achieves RMS temperature residuals below 10 $\mathrm{\mu}$K over 95% of the sky up to 353 GHz, with fractional residuals below 1.5% in the
Galactic plane and below 5% across QUIJOTE bands. Residual angular power spectra lie more than two orders of magnitude below the CMB spectrum. These products describe the transition between
radio and microwave emission and provide a new reference for foreground modeling and sky-simulation applications.
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All authors Gabriel A. Hoerning, Clive Dickinson, Stuart E. Harper, Roke Cepeda-Arroita, Hans K. Eriksen, Melis O. Irfan, J. Patrick Leahy, Jamie Leech, Michael E. Jones, Timothy J. Pearson, Michael W. Peel, Vasundhara Shaw, Angela C. Taylor, Duncan J. Watts, Ingunn K. Wehus, Gilles Weymann-Despres
General Relativity and Quantum Cosmology
Thermal Stability and QNMs of a Hairy Black Hole in the Presence of a Monopole Field
George Koutsoumbas, Andri Machattou and Eleftherios Papantonopoulos
We study the stability of a generalization of the GHS-GM black hole in the presence of a dilaton and a monopole field. We find that the thermal behaviour of system depends on the scalar charge of the dilaton field and as this parameter is decreasing the system becomes more thermally stable. We also find that, as the charge of the black hole is increasing, both the real and the imaginary parts of the quasi-normal frequencies decrease in absolute value. The overtone modes die out faster than the fundamental modes and no positive imaginary parts appear, indicating the stabilty of the system
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Medical Physics
Patient-specific immobilisation for radiotherapy treatment of extensive lower-limb carcinoma
Tanya Kairn, Tania Poroa, Jenna Luscombe et al. (+3 more)
When non-melanoma skin cancers extend over large areas of skin, effective radiotherapy treatments can be delivered using volumetric modulated arc therapy (VMAT) beams with narrow segments that rotate around the affected surfaces. For lower-limb carcinoma treatments, careful immobilisation is needed to achieve the degree of reproducible and stable positioning required to ensure the narrow field segments treat the targeted tissue and avoid underlying anatomy. To meet this need, a 3D printed patient-specific foot support was created in the form of a solid box containing a deep “footprint”, shaped to match the outline of the patient's relaxed foot when lying supine, supported by a
vacuum bag. For our first patient treated with a 3D printed foot support, image guidance data and clinical notes were evaluated against corresponding information from all recent lower-leg VMAT treatments. The patient feedback was recorded as “good”, with no complaints of discomfort or poor fit, and the proportion of treatment fractions requiring shifts greater than 5 mm after setup imaging (20%) compared favourably to the proportions for patients without a patient-specific foot support (23%-84%). The patient-specific foot support was particularly useful for minimising longitudinal shifts and leg rotations. Evidently, 3D-printed patient-specific immobilisation devices have the potential to enhance positioning stability, and therefore potentially improve accuracy and effectiveness of VMAT treatments, for patients with extensive lower-limb carcinomas.
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All authors Tanya Kairn, Tania Poroa, Jenna Luscombe, Shaun Chan, Michelle Grogan, Scott B. Crowe
Fluid Dynamics
Flow mechanisms governing oscillation in a sonic fluidic oscillator
Chris J. Nicholls, Michael R. Fenelon, Yang Zhang et al. (+1 more)
Two factors that influence the oscillation mechanism of a sonic fluidic oscillator are investigated: the geometry of the feedback channel connections (control ports) and the influence of flow restrictions in the oscillator outlets. Phase-averaged planar PIV measurements are performed inside the oscillator, synchronised with unsteady pressure measurements, and analysed using space-only proper orthogonal decomposition (POD). The POD analysis reveals two coupled modes: a Sweeping Mode capturing lateral jet displacement and a Bending Mode capturing jet
curvature during switching, the latter being the primary driver of outlet mass flux modulation. Flow separation at the control port entrances is shown to throttle the feedback flow and progressively limit oscillation strength at higher inlet flow rates. Restrictive outlet paths induce a differential back pressure that is shown to cause the jet to separate from its attachment wall and bend towards the splitter tip (`secondary separation'). The secondary separation reduces the differential outlet mass flux and introduces a flow
curvature that limits the upstream propagation of the back pressure and thus shields the primary jet attachment. The consequence of these effects is that strong oscillations are sustained down to the smallest outlet apertures investigated. The principal contribution is to demonstrate that the assumed coupling between upstream jet attachment and outlet flow split is broken when the outlet aperture is reduced, with significant implications for the design of fluidic oscillators operating with downstream flow impedances.
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All authors Chris J. Nicholls, Michael R. Fenelon, Yang Zhang, Louis N. Cattafesta III
Quantum Physics
Temporal processing of quantum states with hybrid quantum-classical reservoirs
Mateu Coll-Comas, Gian Luca Giorgi and Roberta Zambrini
A distinctive feature of
Quantum Reservoir Computing (QRC) is the ability to directly embed
quantum input states into the reservoir dynamics. However, the resulting output is fundamentally linear for a single input state, preventing QRC from naturally computing nonlinear functionals such as purity or
entropy. We overcome this limitation with a
quantum-classical hybrid architecture combining a
qubit quantum reservoir with a classical echo state network (ESN), allowing both nonlinear functional approximation and effective temporal processing. We systematically study performance under two information regimes: full-
tomography and partial information (single-axis measurements), with the latter demonstrating that the hybrid system outperforms its standalone components in both linear and nonlinear tasks due to the enhanced information
retrieval provided by the
quantum reservoir. Building on these results, we apply an online monitoring protocol that explicitly accounts for measurement back-action and finite measurement ensembles, enabling a realistic assessment of performance under experimental conditions. These results establish hybrid
quantum-classical reservoir computing (HRC) architectures as a practical and scalable route for enhanced
quantum machine learning on near-term
qubit hardware.
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Soft Condensed Matter
Quasi-one-dimensional motion of an active MXene sheet driven by chemo-hydrodynamic waves
Hui Wang, Huan Liu, Ling Yuan et al. (+4 more)
Signal-driven motion is widespread in natural and artificial systems, yet quantitative characterization of how transient chemo-hydrodynamic waves are converted into mechanical driving forces remains limited. Here, we investigate the self-propulsion of a MXene sheet asymmetrically coated with catalase in hydrogen peroxide solution. By combining dual-view particle image velocimetry experiments and numerical simulations reveal that active motion of the sheet is driven by chemo-hydrodynamic waves and exhibits direct-wave motion, the driving force of which is analyzed in terms of the shear stress on the sheet surface caused by chemo-hydrodynamic waves. This work suggests theoretical principles for designing and controlling hydrodynamically driven active motion.
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All authors Hui Wang, Huan Liu, Ling Yuan, Zihao Liu, Meng Zhang, Irving R Epstein, Qingyu Gao
Strongly Correlated Electrons
Importance of effective Coulomb interactions for $T_c$ in cuprates
Jakša Vučičević, Upendra Kumar, Chia-Nan Yeh et al. (+2 more)
Cuprate
superconductors exhibit the highest observed superconducting $T_c$ at atmospheric pressure. However, the magnitude of $T_c$ varies significantly between different cuprates. At present, it is unclear what properties of the
crystal structure affect $T_c$ most strongly, yet such an understanding must underpin any efforts toward high-$T_c$ materials design. To address this issue, we perform a large scale systematic study, employing a combination of data collection, state-of-the-art numerical methods, and statistical analysis. We identify about 40 different cuprate compounds, and we compile detailed data about their $T_c$'s and
crystal structures from literature and the available databases. Using a fully automated procedure, for each compound we compute the DFT bandstructure and downfold it to two of the most commonly studied low-energy
lattice models, namely the single-band Hubbard and the three-band Emery models. The downfolding is based on the approach of MLWFs and cRPA. Finally, we apply a thorough and unbiased statistical analysis to investigate the correlations between the experimentally measured $T_c$'s and the computed parameters of our theoretical models. Our data indicates that more sophisticated models might be needed to describe all cuprates on the same footing. Nevertheless, we find that $T_c$ scales well with simple functions of model parameters. We confirm a previously observed trend that $t'$ in the single-band model correlates with the experimental $T_c$, and we find that $T_c$ appears to vanish below a finite value of $t'$, in agreement with recent ground-state calculations for the Hubbard model. However, we find that the coupling strength also plays a role: throughout our entire
dataset, $T_c$ correlates the most with the Coulomb coupling on the $p$-orbitals in the 3-band model, highlighting the importance of the oxygen sites in the copper-
oxide planes.
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All authors Jakša Vučičević, Upendra Kumar, Chia-Nan Yeh, Miguel A. Morales, Malte Rösner
Chaotic Dynamics · Cross-listed from cs.LG
Distinguishing indistinguishable attractors: Unsupervised anomaly detection with reservoir computers
Davide Prosperino, Haochun Ma and Christoph Räth
Detecting when a nonlinear dynamical system departs from its normal regime is a recurring problem across the sciences, from cardiology to
climate and energy systems. We show that a very simple Kolmogorov–Smirnov test on the output weights of a reservoir computer is highly sensitive to regime changes in nonlinear dynamical systems, including those invisible to both classical nonlinear measures and modern deep-learning detectors. The core idea of our
algorithm is to treat the readout layer of a reservoir computer as a representation of the input dynamics. Since the input mapping and the reservoir itself are random and fixed, the trained output weights are the only object encoding the system at hand. We summarize this fingerprint by the empirical cumulative distribution function of the readout weights and compare it to a reference band built from the training data. This unsupervised, online detector distinguishes two visually indistinguishable butterfly-shaped attractors, resolves parameter drifts seven times smaller than the strongest deep-learning baseline, flags noise four orders of magnitude below the signal, and identifies ventricular flutter in a clinical ECG recording. More broadly, we aim to establish a perspective on reservoir computers in which the trained output weights are treated as a representation of the learned system in their own right, rather than merely as a means to
forecasting.
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Medical Physics
Adapting a 3D scanning water phantom for use in brachytherapy dosimetry
Rachael Wilks, Samuel C. Peet, Tanya Kairn et al. (+1 more)
In external beam radiotherapy, 3D scanning water phantoms are the gold standard for obtaining relative dosimetry data. These phantoms, consisting of a water tank and mechanical arm, along with accompanying software, are de-signed to acquire dose profiles along and orthogonal to the beam axis. In brachy-therapy, the acquisition of analogous dose profiles is more difficult, and is generally achieved with complex custom-built phantoms or chemical dosimeters such as film or gel. In this study, a low-cost 3D-printed jig was designed and fabricated within a clinical department, to allow precise brachytherapy dose measurements using a PTW BeamScan water phantom. Specifically, this jig al-lowed applicators to be suspended securely and reproducibly within the water phantom. Protocols were developed to relate the scanning system coordinates to the physical source position, and to obtain isodose planes both parallel and radial to the source axis. The developed solution has the potential to be used for physical verification of TG43 dose calculation parameters (e.g. anisotropy functions), the characterization of dose for a single dwell position in a complex applicator containing non-water equivalent materials, or the collection of point dose measure-ments for treatments incorporating multiple dwell positions or catheters.
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All authors Rachael Wilks, Samuel C. Peet, Tanya Kairn, Scott B. Crowe
Statistical Mechanics
From Landau Equation and Large Deviations to Efficient Simulations of Dynamical Fluctuations
Anwar El Rhirhayi, Jean-Baptiste Fouvry and Julien Barré
The (deterministic) Landau equation captures the mean long-term
evolution of dynamically hot long-range interacting finite-$N$ systems. Though successful, this kinetic equation fundamentally ignores dynamical fluctuations. Building upon Large Deviation Theory, we present a physically-consistent system of Langevin equations that simultaneously recovers the mean Landau dynamics and accurately captures the corresponding fluctuations among different realizations. We show in particular how these Langevin equations can be derived from Rostoker's principle in the limit of weak two-body deflections. We extensively validate these equations against tailored direct $N$-body simulations, showing an exquisite level of agreement.
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High Energy Physics (Phenomenology)
Large Language Model-Assisted Framework for BSM Model Building
Shaikh Saad
Recent advances in artificial intelligence (AI), particularly large
language models (LLMs), have created new opportunities for natural-
language interaction with scientific software, but reliable theoretical model building still requires deterministic symbolic calculations. We present bsm_
agent, an open-source symbolic framework for beyond the Standard Model (BSM) model building that combines a deterministic physics backend with an LLM chat interface. Starting from the SM field content and a user-specified set of additional scalars and/or
fermions, the package constructs renormalizable Lagrangian, performs gauge-anomaly checks, expands operators into component fields, and derives electroweak
symmetry breaking stationary conditions and tree-level mass
matrices. The key novelty of the framework is that all of these tasks are performed automatically once the user specifies the
quantum numbers of the new fields through a natural-
language interface, eliminating the need for manual model construction. The symbolic calculations are performed entirely by the Python backend to ensure the correctness and reproducibility of the physics results; the LLM is used only as an orchestration layer that interprets natural-
language requests, manages confirmation steps for ambiguous inputs, triggers backend tools, and formats report-ready summaries. The package supports three provider classes: local Ollama inference, remote self-hosted model servers accessed through the implemented remote provider interface, and commercial hosted APIs via OpenAI and Anthropic. This separation between conversational control and deterministic computation preserves reproducibility while making interactive BSM model construction substantially more convenient.
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Optics
Dynamic dark-field FFOCT and dynamic reflection differential phase contrast for label-free functional imaging at reflective biomaterial interfaces
Tual Monfort
Strong reflections from metallic and engineered substrates severely limit label-free functional imaging of living
cells at biomaterial interfaces, neural electrodes, and implantable devices. Here we introduce two complementary approaches for recovering intracellular dynamic contrast at highly reflective interfaces. Dynamic dark-field full-field optical coherence
tomography (D-dFFOCT) suppresses the dominant substrate reflection and restores intracellular visibility through selective detection of scattered light. In parallel, asymmetric illumination generates a distinct directional dynamic contrast that is most consistently interpreted as dynamic reflection differential phase contrast (D-RDPC). Both approaches reveal intracellular activity that remains poorly visible with conventional dynamic full-field optical coherence
tomography. D-RDPC exhibits characteristic signatures of phase-gradient imaging, including contrast reversal upon illumination inversion, enhancement with increasing illumination asymmetry, and recovery of spatial localization through directional
Hilbert-transform reconstruction. Together, these results establish new strategies for functional imaging at reflective interfaces and suggest that differential phase contrast signals can support temporal fluctuation analysis.
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Medical Physics
Characteristics of a 9 MeV electron beam for total skin electron radiotherapy evaluated in comparison to a 6 MeV electron beam
Tanya Kairn, Craig M. Lancaster and Scott B. Crowe
Characteristics of a 9 MeV electron beam were investigated, to evaluate potential benefits for patients with extensive mycosis fungoides lesions that are deeper than commonly treated with 6 MeV total skin electron therapy (TSET or TSE/TSEI/TSEB/TSEBT). A comprehensive commissioning measurement program was completed for TSET delivery using high-dose-rate 6 MeV and 9 MeV electron beams from a Varian TrueBeam linac. Various phantoms and dosimeters were set up 300 cm from isocenter, behind a 6 mm PMMA spoiler screen, and used for optimising beam-pair gantry angles, measuring depth-dose, lateral and horizontal profiles and B-factors, as well as performing end-to-end tests. The key clinical distinctions observed for the 9 MeV TSET beam pair compared to the 6 MeV TSET beam pair were that the 80% dose depth increased to nearly 1 cm and the practical range increased to 3.5 cm, while the maximum dose remained within 0.2 cm of the surface. Vertical and horizontal dose profiles measured with the two energies were almost indistinguishable. The 9 MeV TSET beam has been shown to achieve greater depth penetration compared to the commonly used 6 MeV TSET beam, without detrimentally affecting the dose uniformity achievable in the patient plane. TSET treatments with 9 MeV electrons may be advisable for patients with extensive lesions that are too deep for effective treatment with a 6 MeV beam.
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Chemical Physics
Property-Specific Molecular Representations via Feature-Space Transfer Compression
Ali Banjafar and Guido Falk von Rudorff
In many machine learning applications, molecules need to be transformed into representations, i.e. mathematical objects. Those representations are typically considered to be property-agnostic and as such are expected to be over-complete: for different physical properties, different parts or the representation may be relevant. In this work, we propose a method to sub-select and re-weight the representation by adapting it to the property in question. We find that in most cases this makes representations shorter and more accurate at the same time. The feature selection itself uses cheap semi-empirical data instead of high-quality labels. We study four properties (total energy, heat capacity, dipole moment, and polarizability) for three representations (cMBDF, FCHL19, and MACE-MP-0 descriptors) on two
datasets (QM9 and VQM24). We can reduce the number of dimensions of a representation in the median by 72\,% (range 36-98\,%) while retaining the accuracy. Tuning for accuracy instead we can increase the learning efficiency for dipole moments such that the same accuracy can be reached with 19\,% of the training data. Our approach yields data-driven interpretations of feature importance, lossless compact representations, and increased data efficiency, requiring only expendable surrogate data.
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Quantum Physics
Time-Bin BB84 QKD System Using Indium Phosphide and Silicon Nitride Photonic Integrated Circuits
Denis Fatkhiev, Alexander Grebenchukov, João dos Reis Frazão et al. (+3 more)
We demonstrate a dual-chip InP-SiN photonic QKD system with on-chip pulse generation and reconfigurable decoding, implementing time-bin BB84 with finite-key security against coherent attacks. The system sustains a QBER below 4% and delivers secret keys at kbps rates over 150-250 km of fiber.
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All authors Denis Fatkhiev, Alexander Grebenchukov, João dos Reis Frazão, Gleb Nazarikov, Chigo Okonkwo, Idelfonso Tafur Monroy
Optics
A dressed polarizability framework for interface-coupled meta-atoms and large-scale metasurfaces
Peng Fu, Jean-Paul Hugonin, Maxime Bertrand et al. (+2 more)
The modeling of large collections of interacting meta-atoms remains a central challenge in photonics because it requires the simultaneous treatment of complex scatterer geometries, multiple scattering, and heterogeneous environments. Here, we introduce the dressed Global Polarizability
Matrix (dGPM), a reduced-order electromagnetic framework in which complex meta-atoms are represented by compact scattering operators that explicitly incorporate the influence of nearby interfaces. The dGPM accurately reconstructs near- and far-field electromagnetic responses for interface-coupled structures, including geometries beyond the practical applicability of conventional T-
matrix approaches. The framework naturally combines interface-coupled and free-space scatterers within a unified multiple-scattering formalism and enables simulations of large ordered and disordered metasurfaces. More broadly, the dGPM extends operator-based electromagnetic modeling to heterogeneous photonic environments while preserving a compact scatterer-based representation, providing an efficient framework for the simulation and design of large-scale photonic systems.
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All authors Peng Fu, Jean-Paul Hugonin, Maxime Bertrand, Kevin Vynck, P. Lalanne