Atomic Physics · Cross-listed from quant-ph
SDQC: Distributed Quantum Computing Architecture Utilizing Entangled Ion Qubit Shuttling
Seunghyun Baek, Seok-Hyung Lee, Dongmoon Min et al. (+1 more)
We propose Shuttling-based Distributed
Quantum Computing (SDQC), a hybrid architecture that combines the strengths of physical
qubit shuttling and distributed
quantum computing to enable scalable trapped-ion
quantum computing. SDQC performs non-local
quantum operations by distributing entangled ion
qubits via deterministic shuttling, combining the high-fidelity and deterministic operations of shuttling-based architectures with the parallelism and pipelining advantages of distributed
quantum computing. We present (1) a practical architecture incorporating
quantum error correction (QEC), (2) pipelining strategies to exploit parallelism in
entanglement distribution and measurement, and (3) a performance evaluation in terms of logical error rate and clock speed. For a 256-bit
elliptic-curve discrete logarithm problem (ECDLP) instance, which requires 2,871 logical
qubits at code distance 13, SDQC achieves a logical error rate which is $1.20^{+0.94}_{-0.45}\times10^{-8}$ of Photonic DQC error rate and $3.79^{+5.09}_{-2.84}\times10^{-3}$ of
Quantum Charge-Coupled Device (QCCD) error rate, while providing 2.82 times faster logical clock speed than QCCD.
Read the full abstract ▾
All authors Seunghyun Baek, Seok-Hyung Lee, Dongmoon Min, Junki Kim
Optics
Terahertz Emission from Spintronic Stack Nanodecorated with Drop-Cast Core-Shell Plasmonic Nanoparticles
Vittorio Cecconi, Akash Dominic Thomas, Ji Tong Wang et al. (+10 more)
Spintronic emitters promise to revolutionise terahertz (THz) sources by converting ultrafast optical pulses into broadband THz radiation without phase-matching constraints. Because the conversion relies on
spin-current injection across a nanometre-thin
magnetic layer, its efficiency is ordinarily limited by weak optical coupling. Here, we present a demonstration of a drop-casting based approach to introduce ultrafast plasmonic-mediated coupling: a sparse-layer of silica-gold core-shell nanoparticles is deposited directly onto a W/Fe/Pt spintronic trilayer. This sparse (six percent) decoration increases the wafer-averaged THz pulse energy, pointing to a very high local conversion enhancement for this low-coverage spintronic emitter compared with the bare stack. This demonstration points to a viable pathway toward highly efficient spintronic terahertz emitters with potential applications in spectroscopy, imaging, and ultrafast technologies.
Read the full abstract ▾
All authors Vittorio Cecconi, Akash Dominic Thomas, Ji Tong Wang, Cheng-Han Lin, Anoop Dhoot, Antonio Cutrona, Abhishek Paul, Luke Peters, Luana Olivieri, Elchin Isgandarov, Juan Sebastian Totero Gongora, Alessia Pasquazi, Marco Peccianti
Applied Physics
A Novel Injection-Locked S-Band Oven Magnetron System Without Waveguide Isolators
S Wang, Y Shen, C Liao et al. (+2 more)
A novel injection-locked S-band microwave oven magnetron system is proposed, analyzed, and experimented. The magnetron is considered as a two-port oscillator, and the filament structures of it are used as a port for injection locking. To our knowledge, it is the first time that microwaves have been injected through magnetron filaments. The microwave is injected into the magnetron filter box using a self-designed injection structure, entering the resonant cavity through filament leads. The intrinsic isolation between the magnetrons output and filament is utilized as an isolator. No waveguide circulators or couplers between the injection source and the magnetron were used in the system, resulting in low cost and compact injection locking. Two types of injection structures were performed. The maximum locking bandwidth of 0.7 MHz was achieved at an injection ratio of 0.2. The weight and volume of the proposed injection-locked magnetron system were reduced to 28% and 16%, respectively. The magnetron output is successfully locked by an external signal. The experiment results reveal that the proposed low-cost injection-locked oven magnetron system works reliably. It has significant potential applications for future microwave ovens with frequency-selective heating to improve both efficiency and uniformity.
Read the full abstract ▾
All authors S Wang, Y Shen, C Liao, J Jing, C Liu
Instrumentation and Detectors
Discovery and rectification of an error in high resistance traceability at NPL: a case study in how metrology works
Stephen Giblin
We broach a seldom-discussed topic in precision metrology; how subtle errors in calibration processes are discovered and remedied. We examine a case study at the National Physical Laboratory (NPL), UK, involving the calibration of DC standard resistors of value 100 MOhm and 1 GOhm. Results from the period 2001 to 2015 were in error by approximately 0.7 parts per million (ppm), with quoted uncertainties (k=2) of 0.4 ppm and 1.6 ppm respectively. Inter-comparisons did not detect the error, mainly because the uncertainty due to the transportation drift of the comparison standards was too large to resolve it. Likewise, research into single-electron current standards did not detect the error because at this resistance value it was on the borderline of statistical significance. The key event was a comparison between PTB (Germany) and NPL (UK) of a new small-current measuring instrument, the ultrastable low-noise current amplifier (ULCA). At that time, the transport stability of the ULCA was not well established. Nevertheless, calibrations of the ULCA at NPL using a 100 MOhm resistor were sufficiently discrepant with the PTB calibrations to motivate a thorough investigation into the NPL traceability chain, which uncovered the error. This instructive episode illustrates a positive interplay between calibration and research activities and shows that cutting-edge calibration uncertainties must be supported by a vigorous research programme. It is also important for NMIs to maintain a comfortable buffer (at least a factor of 10) between their claimed uncertainty and the uncertainty that their customers require, so that small errors can be resolved without significant impact on measurement stakeholders.
Read the full abstract ▾
Optics · Cross-listed from cond-mat.other
Vladimir L. Zhiliakov, Nataliia E. Kopteva, Irina A. Yugova et al. (+3 more)
We theoretically investigate the
spin structure and
spin dynamics of
excitons in bulk lead halide perovskite
semiconductors with cubic, tetragonal, and orthorhombic
crystal symmetry. The
exciton spin structure and its modification by an external
magnetic field are modeled for different regimes defined by the relative magnitude of the electron-hole exchange interaction (splitting between dark and bright states) and the Zeeman
spin splitting. The effects of
crystal symmetry and
magnetic field orientation with respect to the
crystal axes are considered for lead halide perovskite
crystals with band gaps in the range 1.4 - 3.5 eV, having different ratios of electron and hole g-factors. For cubic
symmetry, in a longitudinal
magnetic field, our theory predicts
quantum beats between the bright
exciton states under linearly polarized excitation and detection, while the dark
exciton remains optically inactive. In a transverse
magnetic field, all
exciton spin states become optically active and can be excited by circularly polarized light. Reduction of the
crystal symmetry leads to a zero-field offset of the
exciton Larmor precession frequencies, modifying the Zeeman splitting energy dependence on
magnetic field. This theoretical framework allows for the extraction of the strength of the exchange interaction and the
crystal symmetry. Experimentally, we measure the
exciton spin coherence via time-resolved photoluminescence at a temperature of 1.6 K in longitudinal and transverse
magnetic fields in orthorhombic MAPbI3
crystals. Polarization beats at the frequency of the bright
exciton are observed in both configurations. Comparison with theory indicates that the
excitons are in the strong exchange interaction regime, and the reduction of
symmetry does not lead to a significant splitting of the
exciton spin levels.
Read the full abstract ▾
All authors Vladimir L. Zhiliakov, Nataliia E. Kopteva, Irina A. Yugova, Dmitri R. Yakovlev, Ilya A. Akimov, Manfred Bayer
Optics
Communication-ready high-power soliton microcombs in highly-dispersive Fabry-Perot-microresonators
Yinke Cheng, Zhenyu Xie, Yuanlei Wang et al. (+9 more)
Microcombs generated in optical microresonators are widely regarded as promising light sources for next-generation communication systems, but the optical power available per comb line has so far fallen short of practical requirements. Here we introduce an integrated Fabry-Pérot microresonator platform that overcomes fundamental dispersion-engineering constraints and enables bright
soliton microcombs with unprecedented power per line. The resonator is defined by chirped Bragg gratings that provide exceptionally large anomalous group-velocity dispersion, allowing more than ten comb lines to reach the milliwatt level. These combs can be used directly in coherent communication systems without additional amplification, achieving an aggregate data rate of 2 Tb/s. Once integrated, our high-power
soliton microcombs could be instantly ready for communications as well as a broad range of practical comb-based applications.
Read the full abstract ▾
All authors Yinke Cheng, Zhenyu Xie, Yuanlei Wang, Binbin Nie, Xing Jin, Haoyang Luo, Junqi Wang, Zixuan Zhou, Qihuang Gong, Lin Chang, Yaowen Hu, Qi-Fan Yang
History and Philosophy of Physics
Limiting Reduction and Modified Gravity
Antonis Antoniou and Lorenzo Lorenzetti
Modified Newtonian Dynamics (MOND) is a framework of theories that adjust Newton's laws of
gravity to explain effects such as
galactic rotation anomalies, offering an alternative to dark matter. This essay examines the justification of MOND by assessing its inter-theoretical relationship to established theories across relevant scales, in particular its connection to Newtonian gravitation. We argue that MOND fails a key condition for a theory's justification–what we call 'reduction-wise justification'–since it does not adequately reduce to Newtonian
gravity in a fully non-arbitrary way. More precisely, despite satisfying the standard formal criteria for successful limiting reduction, MOND does not properly reduce to Newtonian gravitation because of (i) the absence of a fundamental theoretical framework to justify the interpolating function introduced in MOND and (ii) the lack of a unified mathematical structure working across all scales, independent of Newtonian theory. Hence, the case study of MOND provides crucial results for the general debate on inter-theoretic reduction in science: MOND's failure as a case of reduction highlights important limitations in standard accounts of limiting reduction. We respond by proposing a more refined framework for limiting reduction that introduces two additional criteria to better distinguish successful from pathological reductions. More broadly, this case illustrates how analysing reduction-wise justification can serve as a powerful tool for evaluating the validity of novel theories that are not yet empirically established.
Read the full abstract ▾
Biological Physics · Cross-listed from cond-mat.soft
Modulation of DNA rheology by a transcription factor that forms aging microgels
Amandine Hong-Minh, Yair Augusto Gutiérrez Fosado, Abbie Guild et al. (+4 more)
Proteins and nucleic acids form non-Newtonian
liquids with complex rheological properties that contribute to their function in vivo. Here we investigate the rheology of the transcription factor NANOG, a key
protein in sustaining embryonic stem
cell self-renewal. We discover that at high concentrations NANOG forms macroscopic aging gels through its intrinsically disordered tryptophan-rich domain. By combining molecular dynamics simulations, mass photometry and Cryo-EM, we also discover that NANOG forms self-limiting micelle-like clusters which expose their DNA-binding domains. In dense solutions of DNA, NANOG micelle-like structures stabilize intermolecular entanglements and crosslinks, forming microgel-like structures. Our findings suggest that NANOG may contribute to regulate gene expression in a unconventional way: by restricting and stabilizing genome dynamics at key transcriptional sites through the formation of an aging microgel-like structure, potentially enabling mechanical
memory in the gene network.
Read the full abstract ▾
All authors Amandine Hong-Minh, Yair Augusto Gutiérrez Fosado, Abbie Guild, Nicholas Mullin, Laura Spagnolo, Ian Chambers, Davide Michieletto
Geophysics
Leveraging generative adversarial networks with spatially adaptive denormalization for multivariate stochastic seismic data inversion
Roberto Miele and Leonardo Azevedo
Probabilistic seismic inverse modeling often requires the prediction of both spatially correlated geological heterogeneities (e.g., facies) and continuous parameters (e.g., rock and elastic properties). Generative
adversarial networks (GANs) provide an efficient training-image-based simulation framework capable of reproducing complex geological models with high accuracy and comparably low generative cost. However, their application in
stochastic geophysical inversion for multivariate property prediction is limited, as representing multiple coupled properties requires large and unstable networks with high
memory and training demands. A more recent variant of GANs with spatially adaptive denormalization (SPADE-GAN) enables the direct conditioning of facies spatial distributions on local probability maps. Leveraging on such features, an iterative geostatistical inversion
algorithm is proposed, SPADE-GANInv, integrating a pre-trained SPADE-GAN with geostatistical simulation, for the prediction of facies and multiple correlated continuous properties from seismic data. The SPADE-GAN is trained to reproduce realistic facies geometries, while sequential
stochastic co-simulation predicts the spatial variability of the facies-dependent continuous properties. At each iteration, a set of subsurface realizations is generated and used to compute synthetic seismic data. The realizations providing the highest similarity coefficient to the observed data are used to update the subsurface probability models in the next iteration. The method is demonstrated on both 2-D synthetic scenarios and field data, targeting the prediction of facies, porosity, and acoustic impedance from full-stack seismic data. Results show that the
algorithm enables accurate multivariate prediction, mitigates the impact of biased prior data, and accommodates additional local conditioning such as well logs.
Read the full abstract ▾
Plasma Physics
Qubit Lattice Algorithm Simulations of the Scattering of a Bounded Two Dimensional Electromagnetic Pulse from an Infinite Planar Dielectric Interface
Min Soe, George Vahala, Linda Vahala et al. (+3 more)
Qubit lattice algorithm (QLA) simulations are performed for a two-dimensional (2D) spatially bounded pulse propagating onto a plane interface between two dielectric slabs. QLA is an initial value scheme that consists of a sequence of
unitary collision and streaming operators, with appropriate potential operators, that recover Maxwell equations in inhomogeneous dielectric media to second order in the
lattice discreteness. For the case of total internal reflection, there is transient energy transfer into the second medium due to the evanescent fields as the Poynting unit vector of the pulse is rotated from its incident to reflected direction. Because of the finite spatial extent of the pulse, a self-consistent Goos-Hanchen-type displacement along the interface is found without imposing any explicit interface boundary conditions on the fields. For normal incidence. the standard Fresnel coefficients are recovered for appropriately averaged QLA fields. Energy is conserved at all times to seven significant figures.
Read the full abstract ▾
All authors Min Soe, George Vahala, Linda Vahala, Efstratios Koukoutsis, Abhay K. Ram, Kyriakos Hizanidis
Physics Education
A Critical Analysis of Affirmative Action and Academic Performance: A Response to the Preprint Authored by Matheus et al. (2025)
Claudio Andre Barbosa de Lira and Ricardo Borges Viana
This article offers a critical response to the preprint by Matheus et al. (2025), which evaluates the academic performance of students admitted through different entry routes at Sao Paulo State University. Although the
dataset compiled by the authors is valuable, their analysis contains conceptual, methodological, and historical limitations that undermine the validity of their conclusions. We argue that the preprint misinterprets the purpose of Brazil's affirmative action policy, which is intended to ensure equitable access rather than equalize academic performance at the point of university entry. Early performance differences among universal system, public school, and racial-quota students reflect longstanding inequalities in Brazil's basic education system. Furthermore, the preprint generalizes findings basically from only three undergraduate programs (Physics, Biology, and Pedagogy) to represent entire academic domains (STEM, Biological Sciences, and Humanities), an extrapolation that reduces the reliability of its conclusions. Overall, we contend that early performance differences indicate structural educational inequality, not policy failure. Affirmative action fulfills its mandate by guaranteeing access, while universities bear the responsibility for providing equitable conditions for academic progression.
Read the full abstract ▾
Physics Education
Learning Science and the Illusion of Understanding: Exploring the Effects of Integrating Learning Tasks after Explainer Videos
Madeleine Hörnlein and Christoph Kulgemeyer
Explainer
videos are increasingly used to support science learning. While prior research has demonstrated their potential, studies have also identified limitations - particularly their tendency to foster an illusion of understanding, where learners overestimate their grasp of a topic despite gaps in their actual knowledge. Pairing explainer
videos with cognitively engaging elements may help mitigate this effect. This paper reports two experimental studies examining the immediate and long-term effects of learning tasks following a physics explainer
video on learners' illusion of understanding. Study 1 (N = 244 learners) compared high-level learning tasks with watching the
video alone. Study 2 (N = 175) compared high-level and low-level tasks. Results show that high-level learning tasks significantly reduce the illusion of understanding immediately after the intervention compared to watching the
video alone (t(88) = 6.50, p < .001, d = 0.69). Over the long term, both high-and low-level tasks are similarly effective. Learners with lower prior content knowledge are more susceptible to an illusion of understanding. We conclude that explainer
videos should not be used in isolation in science classrooms. To prevent misjudged understanding - particularly among students with limited prior knowledge - they should be combined with cognitively demanding follow-up activities.
Read the full abstract ▾
Atmospheric and Oceanic Physics
Q-triplet characterization of atmospheric time series at Antofagasta: A missing values problem
Hishan Farfán-Bachiloglu, Francisco A. Calderón and Darío G. Pérez
Located in northern Chile (23.7{\deg}S, 70.4{\deg}W), Antofagasta has an exceptionally arid and stable
climate characterized by minimal precipitation and consistent weather patterns. Nevertheless, despite these
climate conditions being meaningful for several research and practical applications, our understanding of weather dynamics remains limited. The available meteorological data from 1969 to 2016 is analogical, which presents a significant challenge to analyze because these records are riddled with missing values, some measurements were taken at irregular measuring intervals, making it an interesting puzzle to grasp the Antofagasta's
climate scenario. To overcome this issue, we present a comprehensive statistical analysis of atmospheric temperature, pressure, and humidity time series. Our analytical approach involves the q-triplet calculation method, serving as a powerful tool to identify distinctive behavior within systems under non-
equilibrium states. Our results suggest that, in general, the q-triplet values satisfy the condition $q_\text{sens}<1<q_\text{stat}<q_\text{rel}$, a pattern that has been observed in previous studies.
Read the full abstract ▾
Optics · Cross-listed from gr-qc
Universality and Falsifiability of Quantum Spacetime Decoherence: A Gauge-Invariant Framework for Gravitational-Wave Phase Diffusion
Hu Cang and Yuan Wang
We develop a fully gauge-invariant and rigorously derived framework for computing the cumulative decoherence of gravitational waves (GWs) propagating through a
stochastic quantum spacetime. Working directly with the Riemann-tensor two-point function and exploiting the extreme adiabaticity of cosmological GW propagation, we show that phase
diffusion, rather than amplitude attenuation or mode mixing, is the unique leading-order imprint of microscopic
curvature fluctuations. Our main theoretical result is a universality
theorem: for any
quantum-
gravity model whose
curvature fluctuations possess a finite correlation length, the accumulated phase variance grows linearly with distance, independent of the underlying microphysics. This diffusive scaling contrasts sharply with coherent astrophysical effects and with nonlocal models. The frequency exponent therefore becomes a clean spectral discriminator, separating string-foam
recoil,
holographic or scale-invariant noise, and causal-set discreteness. We obtain these results from first principles by evaluating the projected Riemann correlator along null geodesics and determining the exact conditions under which deviations from universality can arise. Finally, we outline a hierarchical
Bayesian strategy for measuring this effect with LIGO, LISA, and
Pulsar Timing Arrays. Although standard Planck-scale fluctuations remain far below current sensitivity, this framework provides a sharp and falsifiable test of exotic
quantum-spacetime scenarios, particularly those with macroscopic correlation lengths or strong energy dependence.
Read the full abstract ▾
Chemical Physics
Enhanced particle diffusion in fluctuating binary environments
Fivos Perakis, Takeshi Kawasaki and Shinji Saito
We investigate single-particle
diffusion in a two-state Langevin model where the friction coefficient randomly switches between low-friction (
liquid-like) and high-friction (glassy-like) states. The dynamics are governed by the ratio between the friction switching time $\tau$ and the intrinsic velocity relaxation time $\tau_0$. For fast switching ($\tau/\tau_0 \lesssim 1$) the motion is homogeneous and Brownian, whereas for slow switching ($\tau/\tau_0 \gg 1$) the particle exhibits intermittent dynamics and an enhanced
diffusion coefficient. Analysis of the single-particle overlap function $Q(t)$ and the dynamic susceptibility $\chi_4(t)$ reveals decoupling of the
diffusion coefficient from the average friction upon cooling, which coincides with increasing temporal dynamic heterogeneity. This minimal model provides a transparent framework for understanding single-particle transport in media with fluctuating local mobility, including supercooled
liquids and phase-separated soft materials.
Read the full abstract ▾
Instrumentation and Detectors
Position-Sensitive Silicon Photomultiplier Array with Enhanced Position Reconstruction by means of a Deep Neural Network
Cyril Alispach, Fabio Acerbi, Hossein Arabi et al. (+4 more)
Single-
photon sensitive detectors like Silicon Photomultipliers are widely used in many medical imaging applications. By using detectors with position resolutions, it is possible to build compact photodetector readouts with reduced number of channels, but still preserving position resolution and gamma-rays imaging capabilities. In this work, we present the advantage of using a Deep Neural Networks (DNNs) light position reconstruction applied to a 2x2 array of linearly-graded SiPMs (LG-SiPMs), to minimize the distortions on the reconstructed event maps. Our approach significantly enhances both the resolution and linearity of position detection compared to the nominal reconstruction formula based on the device architecture. Remarkably, the DNN-based reconstruction boosts the number of resolved areas (pixels) by a factor of 5.7 to 12.1 (depending the training splitting used) allowing for a higher level of precision and performance in light detection.
Read the full abstract ▾
All authors Cyril Alispach, Fabio Acerbi, Hossein Arabi, Domenico della Volpe, Alberto Gola, Aramis Raiola, Habib Zaidi
Optics · Cross-listed from cond-mat.mes-hall
Topological Pseudospin Hall Effect and Multi-frequency Corner Modes in Kagome-based Lattices
Shenglong Guo, Qinhui Jiang, Yuma Kawaguchi et al. (+2 more)
Topological phases and modes, including pseudospin-
Hall-selective edge transport and corner states, provide robust control of wave propagation and modal confinement in classical wave platforms. Under a tight-binding framework, we theoretically investigate two
lattice designs derived from the kagome
lattice. These extended kagome
lattices support a series of localized modes, including pseudospin-
Hall-like topological edge states and corner modes in different bandgaps and frequencies, which were not only achieved under lower
lattice symmetries than Wu-Hu
lattices, but also enable more degrees of freedom in topological and localized modes. By introducing two types of extended kagome
lattices with different topological properties, multiple interesting phenomena, including newly emerged multiple groups of corner states, parametric tunable pseudospin
Hall effect, and type-II corner states without long-range interactions, are found in theoretical models, which are possible and viable to achieve in artificial classical systems such as photonic, acoustic, or electrical
circuits.
Read the full abstract ▾
All authors Shenglong Guo, Qinhui Jiang, Yuma Kawaguchi, Bo Li, Mengyao Li
Atomic Physics · Cross-listed from cond-mat.mtrl-sci
Ultrasensitive Anti-Stokes Luminescence Thermometry in Transition Metal Dichalcogenide Monolayers
Sharada Nagarkar, Fahrettin Sarcan, Elanur Hut et al. (+4 more)
Accurate temperature mapping at the nanoscale is a critical challenge in modern science and technology, as conventional methods fail at these dimensions. To address this challenge, we demonstrate a highly sensitive nanothermometer using anti-Stokes photoluminescence, also known as photoluminescence upconversion (UPL), in monolayer tungsten disulfide ($\mathrm{WS_2}$). Leveraging the direct band gap and strong
exciton-
phonon coupling in the two-dimensional monolayers, we achieve an exceptional relative sensitivity above $4\%\,\mathrm{K}^{-1}$ across the 300 K to 425 K range, ranking it among the best-performing materials reported. A strong resonantly enhanced UPL is observed, confirming the central role of optical
phonons in the upconversion mechanism. Furthermore, we introduce a new analytical model to quantitatively describe the UPL process, taking into account the interplay of
phonon populations, bandgap narrowing, and substrate effects, which predicts resonant temperatures and provides a framework with broad applicability to any material exhibiting an anti-Stokes photoluminescence response. To demonstrate its use as a high-resolution optical thermometer, we map a $20\,^{\circ}\mathrm{C}$ thermal gradient across a $20\,\mu\mathrm{m}$ long monolayer with a spatial resolution of $1\,\mu\mathrm{m}$. With its high sensitivity, strong signal, and excellent reproducibility, our work establishes monolayer transition metal dichalcogenide as a leading platform for non-invasive thermal sensing in advanced microelectronic and biological systems.
Read the full abstract ▾
All authors Sharada Nagarkar, Fahrettin Sarcan, Elanur Hut, Emiliano R. Martins, Stuart A Cavill, Thomas F. Krauss, Yue Wang
Atomic Physics · Cross-listed from quant-ph
Observation of non-Hermitian many-body phase transition in a Rydberg-atom array
Yao-Wen Zhang, Biao Xu, Yijia Zhou et al. (+8 more)
Non-Hermitian
quantum mechanics with parity-time (PT)
symmetry offers a powerful framework for exploring the complex interplay of dissipation and coherent interactions in open
quantum systems. While PT-
symmetry breaking has been studied in various physical systems, its observation on a
quantum many-body level remains elusive. Here, we experimentally realize a non-Hermitian XY model in a strongly-interacting Rydberg-atom array. By measuring the Loschmidt Echo of a fully polarized state, we observe distinct dynamical signatures of a PT-
symmetry-breaking phase transition. Dipole interactions are found to play a crucial role, not only determining the transition point but also triggering a non-Hermitian many-body blockade effect that protects the Loschmidt Echo from decay with a non-monotonic dependence on the system size. Our results reveal intricate interaction-induced effects on PT-
symmetry breaking and open the door for exploring non-Hermitian many-body dynamics beyond single-particle and mean-field paradigms.
Read the full abstract ▾
All authors Yao-Wen Zhang, Biao Xu, Yijia Zhou, De-Sheng Xiang, Hao-Xiang Liu, Peng Zhou, Kuan Zhang, Ren Liao, Thomas Pohl, Weibin Li, Lin Li
Medical Physics
BART Streams: Real-time Reconstruction Using a Modular Framework for Pipeline Processing
Philip Schaten, Moritz Blumenthal, Bernhard Rapp et al. (+2 more)
Purpose: To create modular solutions for interactive real-time MRI using reconstruction
algorithms implemented in BART. Methods: A new protocol for streaming of multidimensional arrays is presented and integrated into BART. The new functionality is demonstrated using examples for cardiac interactive real-time MRI based on radial FLASH, where iterative reconstruction is combined with advanced features such as dynamic coil compression and gradient-delay orrection. We analyze the latency of the reconstruction and measure end-to-end latency of the full imaging process. Results: Reconstruction pipelines with iterative reconstruction and advanced functionality were built in a modular way using scripting. Latency measurements demonstrate latency sufficient for interactive real-time MRI, on the order of 30 ms for BART processing and network transfer time, or 200 ms for end-to-end latency including acquisition, vendor processing, and display. Conclusion: With the new streaming capabilities, real-time reconstruction pipelines can be assembled using BART in a flexible way, enabling rapid prototyping of advanced applications such as interactive real-time MRI.
Read the full abstract ▾
All authors Philip Schaten, Moritz Blumenthal, Bernhard Rapp, Christina Unterberg-Buchwald, Martin Uecker
Optics
Design and optimization of zone plates for flying focus applications
Zhengkun Li, Yisong Zhou, Changbo Fu et al. (+1 more)
Flying focus
laser pulse technology, characterized by programmable velocity profiles and the ability to break the traditional link between focal spot motion and group velocity constraints, holds significant potential for revolutionary advances in high-intensity
laser related fields. However,the flying focus generated with conventional approaches suffers from a low maximum intensity, as the energy is spread over a long distance, and the size of the focusing optics is also limited. Here, we propose a zone-plate-based flying focus scheme in which the zone widths are modulated by a sinusoidal random distribution. Numerical simulations show that the high-order foci produced by the modulated zone plate can be suppressed by more than two orders of magnitude. Meanwhile, the scheme sustains a high-intensity focal region extending over more than 100 Rayleigh lengths. Furthermore, the focal speed can be tuned over a wide range, including values exceeding the speed of light in
vacuum. Owing to these advantages, the proposed modulated zone-plate scheme offers new possibilities for high-intensity
laser physics and holds promise for applications such as
laser wakefield acceleration,
photon acceleration, and more.
Read the full abstract ▾
All authors Zhengkun Li, Yisong Zhou, Changbo Fu, Yugang Ma
Optics
Engineered mode coupling in high-Q microresonators enables deterministic low-repetition-rate soliton microcombs
Yi Zheng, Yang Liu, Haoyang Tan et al. (+4 more)
Soliton optical frequency combs have become key enablers for a wide range of applications, including telecommunications, optical atomic clocks, ultrafast distance measurements, dual-comb spectroscopy, and astrophysical spectrometer calibration, many of which benefit from low repetition rates. However, achieving such low-repetition-rate
soliton microcombs is nontrivial as long cavities require substantially higher pump power, which induces stronger thermal effects that, in turn, exacerbate thermal instability and complicate access to stable
soliton states. The dual-mode pumping scheme, in which a continuous-wave pump couples to both the comb-generating mode and an auxiliary mode, has proven simple and effective for mitigating thermal instability and enabling thermally accessible
soliton generation. Yet, in long-cavity devices, the standard bus-to-resonator coupling conditions for these two modes diverge substantially, resulting in insufficient pump coupling to the auxiliary mode, which makes dual-mode pumping particularly challenging for low-repetition-rate microcombs. In this work, we overcome this limitation by coupling the pump to the auxiliary mode via inter-modal coupling, which can be introduced in racetrack microresonators and engineered by tailoring the cavity bend design. We validate this approach in a high-Q (>$10^7$) silicon nitride microresonator and demonstrate thermally accessible, deterministic single-
soliton generation at a repetition rate of 33 GHz. This work provides a simple and robust pathway for generating low-repetition-rate
soliton microcombs.
Read the full abstract ▾
All authors Yi Zheng, Yang Liu, Haoyang Tan, Yanjing Zhao, Andreas Jacobsen, Kresten Yvind, Minhao Pu
Biological Physics
Invariance under Structure Translation as the Origin of Host Immune Capacity Conservation from Noether's Theorem
Yexing Chen and Peng Cao
Biological processes are reproducible, including immunity. Different healthy individuals can exhibit similar disease courses and protective serum antibody levels when confronting the same pathogen. This widely observed phenomenon is the foundation of almost all immunological experiments and clinical trials. This is regarded as a property of immune homeostasis. But why? Modern studies reveal that the core processes in adaptive immunity are governed predominantly by
stochastic events, including V(D)J recombination and affinity maturation. The final composition of the serum antibody repertoire in each individual is also unique. What constrains these microscopic random processes to converge onto consistent, predictable macroscopic trajectories? What is the consistency behind this degeneracy? Here, we address these questions by introducing a theoretical framework based on Lagrangian analytical mechanics. We reformulate adaptive immune recognition as a dynamical system evolving in a high-dimensional immunological state space, with generalized coordinates representing the immune repertoire configuration and the effective antigenic structure. We identify a continuous
symmetry: the system's action remains invariant under specific translations within the antigenic structure space. Noether's
theorem dictates a consistency constraint, I, which acts as a physical constraint on the system's
evolution. It mandates that, irrespective of the specific
stochastic trajectory taken at the molecular level, the system must converge to the same terminal state for a given challenge. This unified principle offers a first-principles explanation for immune phenomenon. We transform the concept of immune homeostasis from a phenomenological description into a quantifiable, consistent physical entity called Immune Capacity, and establish a foundational framework for a unified, predictive immunology.
Read the full abstract ▾
Optics
Double-Helix based Real-Time Single Particle Tracking
Md Faysal Hossain and Sean B. Andersson
In Real-Time, Feedback-Driven Single Particle Tracking methods, measurements of the emission intensity from a labeled, nanometer-scale particle are used in a feedback loop to track the motion of the particle as it moves inside its native environment, including within living
cells. In this work, we take advantage of Point Spread Function (PSF) engineering techniques that encode the axial position of the particle into the shape of the PSF in the focal plane to eliminate the need for out-of-focal-plane measurements, reducing the complexity of implementation and decreasing the overall measurement time of the control loop. Specifically, we used the Double Helix PSF (DH-PSF) in which a single fluorescent source gives rise to two lobes in the image plane with the lobes rotating in the plane as the particle moves along the optical axis. We designed simple
estimators of the relative error between the particle and the tracker, and a simple proportional feedback controller to regulate that error to zero. We explored the efficacy of the approach through simulation studies, demonstrating the tracking of fast-moving particles (with
diffusion coefficients up to 10 {\mu\text{m}^2/\text{s}}) over long time periods (multiple seconds).
Read the full abstract ▾
Chemical Physics · Cross-listed from cond-mat.mtrl-sci
Rational regulation strategies of interstitial localized electrons in electride: A density functional theory study
L. Zhang, D. Wang, H. Wang et al. (+4 more)
As a class of electron-rich materials, electrides demonstrate promising applications in many fields. However, the required high pressure restricts the practical applications to some extent. This study reveals that the unique feature of electride, i.e., the localization of interstitial electrons, can be greatly enhanced and tuned by self-defective doping, applying tensile/compressive stress, or shear stress. Moreover, the requirement of orbital orthogonality between the valence and core electron wave functions, as well as the Pauli exclusion principle, should be the driven force for the electron interstitial localization; and the exertion of external pressure modifies the available space to accommodate the electronic wave functions, thus enhances the interstitial localization. These discoveries lay down the ground for searching for promising electrides that are practicable at ambient conditions.
Read the full abstract ▾
All authors L. Zhang, D. Wang, H. Wang, J. Li, Y. F. Wang, Q. Wu, Hua Y. Geng
History and Philosophy of Physics · Cross-listed from hep-ph
Chen Ning Yang Retrospective
Stephen L. Adler
Chen-Ning Yang made important contributions to the theory of solvable models in statistical mechanics, including generalizations of the Bethe Ansatz, magnetization in the Ising model, the Lee-Yang circle
theorem, and the Yang-Baxter equation. Most famously, Yang made transformative contributions to the current Standard Model of elementary particle interactions. The proposal of Yang and T. D. Lee, that left-right symetry (parity) is violated in weak particle decays, established that the primary currents involved in weak interactions are left handed. The work of Yang and R. L. Mills gave a framework for force carriers coupling to these currents that are non-Abelian generalizations of the electromagnetic
photon, which unlike the electrically neutral
photon, carry “charges” to which they self-couple . Two decades of work by others on quantization and mass-generation mechanisms then culminated in the Standard Model.
Read the full abstract ▾
Computational Physics · Cross-listed from quant-ph
Efficient Simulation of the 2D Hubbard Model via Hilbert Space-Filling Curve Mapping
Ashkan Abedi, Vittorio Giovannetti and Dario De Santis
We investigate tensor network simulations of the two-dimensional Hubbard model by mapping the
lattice onto a one-dimensional chain using space-filling curves. In particular, we focus on the
Hilbert curve, whose locality-preserving structure minimizes the range of effective interactions in the mapped model. This enables a more compact
matrix product state (MPS) representation compared to conventional snake mapping. Through systematic
benchmarks, we show that the
Hilbert curve consistently yields lower ground-state energies at fixed bond dimension, with the advantage increasing for larger system sizes and in physically relevant interaction regimes. Our implementation reaches clusters up to $32\times32$ sites with open and periodic boundary conditions, delivering reliable ground-state energies and correlation functions in agreement with established results, but at significantly reduced computational cost. These findings establish space-filling curve mappings, particularly the
Hilbert curve, as a powerful tool for extending tensor-network studies of strongly correlated two-dimensional
quantum systems beyond the limits accessible with standard approaches.
Read the full abstract ▾
Optics
Fully Integrated Perovskite Polaritonic Circuits with Tunable Lasing and Nonlinear Amplification
Antonio Fieramosca, Vincenzo Ardizzone, Rosanna Mastria et al. (+17 more)
Photonic integrated
circuits are emerging as a key technology for compact and energy-efficient optical information processing. Yet, their practical implementation remains limited by the intrinsically weak optical nonlinearities of conventional materials, which demand high power and large footprints to achieve significant nonlinear responses.
Exciton-polaritons, hybrid light-matter excitations of semiconducting materials, offer a promising solution by combining strong optical nonlinearities with the high speed and large scalability typical of photonic devices. However, despite their potential, working on-chip polaritonic elements demonstrating room temperature coherent lasing, controllable nonlinear propagation, or amplification have remained elusive. Here we demonstrate a fully integrated perovskite polaritonic
circuit that overcomes these limitations. Using a single-step microfluidic lithographic technique, we realize waveguide
circuits with integrated gratings that simultaneously act as couplers and mirrors, forming in-plane Fabry-Pérot cavities. These structures support robust in-plane polariton lasing between gratings, yielding coherent emission along the waveguide. Furthermore, we observe clear signatures of strong nonlinear self-phase modulation and, for the first time, optical amplification of guided polaritons at room temperature. Our simple, scalable platform opens the way to low-power, highly nonlinear optical
circuits for integrated photonics and neuromorphic architectures operating at room temperature.
Read the full abstract ▾
All authors Antonio Fieramosca, Vincenzo Ardizzone, Rosanna Mastria, Laura Polimeno, Lorenzo Dominici, Umberto Dellasette, Andrea Notargiacomo, Marialilia Pea, Raffaella Polito, Eugenio Maggiolini, Rughianah Gohar Ashfaq, Fabio Bruni, Elisa Fardelli, Simona Sennato, Francesco Todisco, Dario Gerace, Dario Ballarini, Milena De Giorgi, Ilenia Viola, Daniele Sanvitto
Optics
Multimode interface between optical free-space- and waveguide modes
Teresia Stranden, Oussama Korichi, Matias Eriksson et al. (+3 more)
Free-space and on-chip photonic systems are key components in optical communication networks. While free-space beams allow for the flexible generation and manipulation of spatial modes, integrated waveguides provide compact and stable platforms for on-chip signal processing. Bridging these two domains is essential for scalable multi-mode communication networks. Here, we present an efficient, broadband interface capable of converting multiple higher-order free-space Laguerre-Gauss (LG) modes into corresponding waveguide modes using the multi-plane light conversion (MPLC) scheme. We experimentally demonstrate low-crosstalk mode conversion between various set of three LG modes, and the first three TE modes of a multimode silicon waveguide across the telecom C-band. The system operates passively without active switching and can be adapted to different spatial mode sets. This platform provides a pathway to increased data capacities and may enable more compact and efficient multi-mode optical communication and on-chip processing schemes.
Read the full abstract ▾
All authors Teresia Stranden, Oussama Korichi, Matias Eriksson, Matteo Cherchi, George Thomas, Robert Fickler
Chemical Physics · Cross-listed from cond-mat.mtrl-sci
Competing excitonic couplings as origin of mimicked phase transitions in zinc-phthalocyanine single crystals
Lisa Schraut-May, Sebastian Hammer, Luca Nils Philipp et al. (+9 more)
The optical properties of molecular
crystals are largely determined by the excitonic coupling of neighboring molecules. This coupling is extremely sensitive to the arrangement of adjacent molecular units, as their electronic interaction is defined by the relative orientation of the individual transition dipole moments and their wave function overlap. Hence, the optical properties, such as fluorescence, are usually highly anisotropic and good indicators of structural changes during the variation of intensive thermodynamic parameters like temperature or pressure. Here, we discuss the peculiar though archetypical case of $\beta$-phase zinc-phthalocyanine: In single
crystals, we report a sudden change of spectral emission with temperature from a broad, unpolarized Frenkel-
exciton type luminescence to a narrow, highly polarized superradiance-like fluorescence below 80 K. Surprisingly, we find that there is no sign of a discrete structural phase transition in this temperature regime. To understand this apparent contradiction, we perform polarization-, temperature- and time-dependent photoluminescence measurements along different crystallographic directions to fully map the emission characteristics of the
crystal-
exciton. By means of ab-initio calculations on a density functional theory level we conclude that our observations are consistent with a dimer
exciton model when considering thermalized electronic states. As such, our study presents a representative case study on a well-established molecular material class demonstrating that caution is advised when attributing discrete changes in electronic observables to a structural phase transition. As we show for zinc-phthalocyanine in its $\beta$-phase modification, slowly varying excitonic couplings and thermal redistribution of excitations can mimic the same signatures attributed to a structural phase transition.
Read the full abstract ▾
All authors Lisa Schraut-May, Sebastian Hammer, Luca Nils Philipp, Krzysztof Radacki, Gabriele Tauscher, Helena Hollstein, Kilian Strauß, Martin Kamp, Heinrich Schwoerer, Holger Braunschweig, Roland Mitric, Jens Pflaum