Optics
Upper bound to optical forces through the multipolar control of optical beams
Enrique Ayllón-García, Iker Gómez-Viloria, Quimey Pears Stefano et al. (+6 more)
Optical tweezers enable the manipulation of microscopic objects using light, yet the fundamental limits to the optical forces that can be exerted on matter remain unknown. Here we derive a general upper bound to the maximum optical force that can be applied to a particle, based on an expansion of electromagnetic fields into well-defined helicity multipolar modes. This method finds the optimal force for any kind of fields external to the particle, including evanescent fields. We apply the method to homogeneous spherical particles in a stable trap and identify the field distributions that saturate this bound for the trapping stiffness. We further provide experimentally accessible strategies to approach these optimal conditions, including configurations using counterpropagating and single-beam traps. Experiments demonstrate a threefold enhancement of trapping forces relative to conventional designs, while theoretical predictions indicate that order-of-magnitude improvements are achievable for larger particles and high angular momentum beams. Our results establish fundamental design principles for maximizing optical forces and define the ultimate limits of optical manipulation.
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All authors Enrique Ayllón-García, Iker Gómez-Viloria, Quimey Pears Stefano, Jason T. Francis, Ángel Cifuentes, Ásier Mongelos-Martinez, Shah Jee Rahman, Miguel Varga, Gabriel Molina-Terriza
Quantum Physics
Worst-case depth hierarchy for shallow quantum circuits
Min-Hsiu Hsieh, Michael de Oliveira, Sathyawageeswar Subramanian et al. (+1 more)
Circuit depth is a central resource in complexity theory. While bounded-depth classical
circuits admit well-understood hierarchy
theorems, the internal structure of constant-depth
quantum computation remains comparatively unexplored. We prove an explicit depth hierarchy
theorem for $\mathsf{QNC}^0$. For each $d\ge 12$, we construct a family of two-round interactive problems on which no depth-$(d-1)$
quantum circuit can achieve near-perfect success, regardless of gate set,
circuit size, or ancillary
qubits. In contrast, we prove that our construction admits realizations by simple bounded fan-in
quantum circuits of depth larger than $d$ by a small constant factor. Moreover, all bounded fan-in classical
circuits of sublogarithmic depth (in the input size) fail to achieve perfect success on these tasks for every $d$, yielding a hierarchy of problems that show unconditional
quantum advantage of $\mathsf{QNC}^0$ over $\mathsf{NC}^0$. A key obstacle is the scarcity of lower bound techniques for
quantum circuits. To address this, we develop methods to analyze how depth affects a
circuit's ability to realize nonlocal correlations amongst its output
qubits in a fine-grained manner. Our approach exploits the correspondence between constraint systems and nonlocal games, translating group-theoretic constructions into rigid operator-valued constraint systems and then into non-local games. In particular, we construct constraint systems whose unique faithful operator-valued solutions require every perfect strategy, and every near-perfect strategy to a fixed precision, to implement multi-controlled phase operations. This reduces to a nonlocal
unitary-synthesis problem, yielding depth lower bounds for both shallow
quantum and classical
circuits. These results show that increasing depth strictly increases computational power within $\mathsf{QNC}^0$, establishing a genuinely
quantum hierarchy.
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All authors Min-Hsiu Hsieh, Michael de Oliveira, Sathyawageeswar Subramanian, Xingjian Zhang
Mesoscale and Nanoscale Physics
Real-space spectral functions of three-dimensional billion-size topological non-Hermitian matter with tensor networks
Yitao Sun, Jose L. Lado and Guangze Chen
Non-Hermitian systems host unconventional topological phenomena, while real-space spectral calculations in three dimensions remain computationally challenging. Here, we develop a tensor-network framework that combines a quantics-based
matrix-product-operator representation of large real-space tight-binding
Hamiltonians with a non-Hermitian kernel
polynomial method. The Hermitized spectral problem is retained within the compact tensor-network representation, enabling real-space spectral function calculations for systems exceeding one billion
lattice sites. Using this approach, we investigate a three-dimensional non-Hermitian higher-order topological
insulator and resolve its corner-mode spectral response on a billion-site
lattice, demonstrating the scalability and computational reach of the method. By tuning the gain–loss strength, we identify distinct in-gap corner-mode features in the weak- and strong-gain–loss regimes. Our results establish a scalable tensor-network framework for real-space spectral calculations in exceptionally large non-Hermitian
lattice systems.
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Mathematical Physics · Cross-listed from math.AP
Edge modes generated by intersection between 3 energy bands
Clotilde Fermanian Kammerer and Nicolas Frantz
In this contribution, we investigate 2-dimensional model problems of three coupled equations. We assume that the underlying
Hamiltonian presents a symmetric intersection between three
eigenvalues of Dirac's type with a mass function that vanish along a curve. We investigate the existence of edge modes for these models: such functions are solutions of the semiclassical associated
evolution problem that are asymptotic to a coherent state with zero energy and break the correspondence principle by propagating inside the crossing set and not along a classical trajectory.
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Quantum Physics
A short proof of the modified Kretschmann-Schlingemann-Werner conjecture
Satvik Singh
Let $\Phi_1, \Phi_2 : \mathbb{M}_d(\mathbb{C})\to \mathbb{M}_n(\mathbb{C})$ be two
quantum channels with respective Stinespring isometries $V_1, V_2 : \mathbb{C}^{d}\to \mathbb{C}^{n} \otimes \mathbb{C}^{m}$ on any common dilation space $\mathbb{C}^{m}$. We prove that there exists a
unitary $U$ on $\mathbb{C}^{m}$ such that $\|V_1-({\bf1}\otimes U)V_2\|_\infty\leq\sqrt{2\|\Phi_1-\Phi_2\|_\diamond},$ thus resolving vom Ende's modification of the Kretschmann-Schlingemann-Werner
conjecture in the affirmative.
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Materials Science
Twistronic control of shift current in multilayer moiré system
Michele Bagaglini, Cesare Tresca, Federico Bisti et al. (+1 more)
The bulk photovoltaic effect in non-centrosymmetric materials provides an alternative mechanism for the conversion of light into a current response compared to p-n junctions. Among its various contributions, the shift current is particularly attractive because it is governed by the
geometric properties of electronic wavefunctions and can generate large photocurrents in low-dimensional materials. Here, we investigate the
evolution of the shift current response in mono-, bi-, and trilayer H-MoS2, as well as in twisted moiré
bilayers and trilayers. To describe large moiré supercells we develop a Slater-Koster tight-binding model parametrized from first-principles calculations. The resulting electronic structures and shift-current responses are compared with density functional theory calculations and Wannier-interpolated results to verify the accuracy of the approach. The model accurately reproduces the electronic structure near the band edges and captures the main spectral features of the shift current conductivity. We show that twisting breaks the
crystal symmetry and activates additional conductivity tensor components that are forbidden in untwisted structures, leading to new tunable in-plane photocurrent components. Analysis of the shift distance reveals a direct connection between the twist-induced modification of the electronic wavefunctions and the increase of the nonlinear response. Our results establish the twist angle as an effective parameter for engineering shift current generation in multilayer transition-metal dichalcogenide base systems and demonstrate that tight-binding approaches provide a practical route for exploring nonlinear optical phenomena in large-scale moiré materials beyond the limits of conventional first-principles calculations.
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All authors Michele Bagaglini, Cesare Tresca, Federico Bisti, Gianni Profeta
Mesoscale and Nanoscale Physics
Direct Nanoscale Pyroelectric Characterization of a CuInP${}_2$S${}_6$ van der Waals Nanogenerator
Valentin Fonck, Roop K. Mech, Mohammadali Razeghi et al. (+8 more)
Pyroelectric energy conversion offers a route for harvesting time-dependent thermalfluctuations that are abundant in natural and technological environments. Twodimensional ferroelectrics are particularly attractive for this purpose because reduced dimensionality enables ultrathin, mechanically compliant device architectures. Here, we demonstrate direct nanoscale pyroelectric characterization of an out-of-plane van der Waals nanogenerator based on CuInP2S6 (CIPS) encapsulated between few-layer
graphene electrodes. A scanning thermal microscopy (SThM) probe is employed as a localized nanoscale heat source while the electrically generated response is measured in situ through the device electrodes. Harmonic detection isolates the pyroelectric signal from parasitic first-harmonic electromechanical contributions, while finite-element thermal modeling combined with probe calibration enables direct determination of the local pyroelectric coefficient from the measured electrical response. Beyond quantitative characterization, the spatially resolved measurements directly identify electrically inactive regions associated with device defects, revealing local performance-limiting features that remain hidden in conventional spatially averaged pyroelectric measurements. The presented approach establishes a versatile platform for quantitative nanoscale pyroelectric characterization and the optimization of van der Waals pyroelectric devices.
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All authors Valentin Fonck, Roop K. Mech, Mohammadali Razeghi, Stuart Finch, Aljoscha Söll, Phillip Dobson, Jonathan R. Weaver, Zdenek Sofer, Oleg Kolosov, Jean Spièce, Pascal Gehring
High Energy Physics (Theory)
Effect of $\xi R\phi^2$ non-minimal coupling on gravitational light bending
Ayan Kumar Naskar, Avijit Sen Majumder and Sourav Bhattacharya
We investigate the bending of massless fields by a massive object in the presence of a
curvature-scalar $\sqrt{-g}\xi R \phi^2$ non-minimal coupling up to one loop, using the perturbative
quantum gravity computations. It is well known that without such coupling a self interacting scalar field theory cannot be renormalised in the presence of
gravity. The massive object is modelled by a massive scalar $\phi$, and it is assumed to be non-relativistic, e.g., a
star. We compute the 2-2 scattering of massless scalar and
photons off this object via graviton exchanges. Assuming both $\xi$ and the bending angle to be small, we use the eikonal approximation to compute the angle up to ${\cal O}(\xi G^2)$. At tree level $({\cal O}(\xi G))$ we find no bending, and hence the ${\cal O}(\xi G^2)$ result happens to be leading in this case. The non-minimal vertices are qualitatively different from that of the standard minimal ones, e.g. $ \sqrt{G} h_{\mu\nu} T^{\mu\nu}$, as the former contains explicit momenta of the gravitons instead of the scalar, complementing the second. The bending angle is found to behave like $\sim b^{-7}$, where $b$ is the impact parameter. We have emphasised the qualitative differences of our results from that of the well studied minimal case.
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Astrophysics of Galaxies
Co-evolution of bar and spiral arms in TNG50 simulations using Information Theory
Anagha A G and Arunima Banerjee
Using Information Theory, we investigate the co-
evolution of bars and spiral arms in barred-spiral
galaxies from the cosmological magneto-hydrodynamic Illustris TNG50 simulations. We first calculate Mutual Information (MI) between a structural or kinematic parameter of the bar (bar strength $A_{2bar}$, bar length $r_{bar}$, bar pattern speed $\Omega$) and that of a spiral arm (spiral strength $A_{2spiral}$, spiral arm pitch angle $\Psi$). We calculate MI in two different
galaxy samples: (i) one forming bars before spirals (ii) other forming spirals before bars. We note, spirals form immediately after bars in the first sample, whereas bars form 1.7 Gyrs after spirals in the second. We find a high mean MI value in each of these samples (0.4 - 0.5), and in the combined sample (0.4-0.8), confirming a fair degree of association of the bar and the spiral arm. To identify whether the bar or the spiral arm effectively drives their co-
evolution, we calculate the Transfer
Entropy (TE) (bar-to-spiral TE, spiral-to-bar TE), from the time series data of each of the above bar-spiral parameter pairs. We find that the median bar-to-spiral TE and spiral-to-bar TE values vary between $ 0.33$ and $ 0.42$ for each
galaxy sample, comparable to those of the combined sample. A similar trend was observed in our calculated Liang information flow rates. Our novel approach may possibly indicate that the bar and the spiral arm regulate their co-
evolution on an equal footing.
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Disordered Systems and Neural Networks
Non-Equilibrium Model Selection via Finite-Time Thermodynamics
Masayuki Ohzeki
Information criteria such as WAIC and WBIC extend model selection to singular learning machines, but they are usually derived for
equilibrium posteriors. We formulate a finite-time analogue of WBIC by replacing the
equilibrium posterior with an effective ensemble generated by learning dynamics under a resource constraint. When this ensemble admits an analytic effective potential, singular learning theory yields a resource-dependent real log canonical threshold. The resulting
estimator gives a computable thermodynamic contribution to time-bounded MDL and identifies the finite-time singular complexity relevant to the structural information measured by epiplexity.
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Optics
Octave bandwidth 3D-Printed Couplers for Low-Loss Thin-Film Lithium Tantalate Circuits
Erik Jung, Xinyu Ma, Jan Brandes et al. (+9 more)
Low-loss, broadband photonic integrated
circuits (PICs) are critical enablers for optical communications, photonic computing, and
quantum applications. Lithium tantalate on
insulator (LTOI) is an emerging photonic platform offering a wide transparency window and strong Pockels effect, and thereby enabling efficient electro-optic modulation and high data rates. Here, we present the first implementation of efficient out-of-plane
polymer coupling interfaces fabricated via 3D direct
laser writing for both fully etched strip and partially etched rib LTOI waveguides, achieving ultra-low coupling losses of 0.9 dB (strip) and 1.25 dB (rib) per interface. Both coupler types exhibit a 3 dB optical bandwidth spanning more than an octave from 850 nm to 1740 nm and maintain stable operation under 1 W optical input power. Combined with on-chip waveguides exhibiting propagation losses below 0.1 dB/cm, these characteristics represent a key step toward unlocking the full potential of LTOI for high-speed optical signal processing with an unprecedented degree of parallelism. In addition, the octave-spanning bandwidth enables efficient interfacing of both the fundamental and second-harmonic signals, making the platform highly attractive for second harmonic generation based
quantum squeezing applications.
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All authors Erik Jung, Xinyu Ma, Jan Brandes, Caghan Ünlüer, Shabnam Taheriniya, Seongmin Jo, Philipp Schmidt, Eric Biedert, Liam McRae, Julian Rasmus Bankwitz, Frank Brückerhoff-Plückelmann, Wolfram Pernice
Strongly Correlated Electrons
Quantum oscillations in proximity to high-angular-momentum band inversion
Jiahao Yang and Gang v. Chen
Quantum oscillations provide a fundamental probe of electronic structure in
magnetic fields, revealing the
Fermi surface
topology in metals, and/or the quasiparticle properties even in the insulating regimes. Here we study
quantum oscillations in minimal models of high-angular-momentum (HAM) band inversion for both a
chiral two-band model and a time-reversal-invariant four-band model. In the former case, finite oscillations can appear at the hybridized Chern-insulating regime due to thermal-activated excitations. In the latter case, interference between the two time-reversal-related blocks drives a strong deviation from the Lifshitz-Kosevich form, producing a non-monotonic temperature dependence of the oscillation amplitude and characteristic suppression temperatures whose number follows the angular momentum $l$. These results identify experimentally accessible signatures of HAM band inversion and provide a framework for other discrete-
symmetry-related hybridizations and excitonic pairings.
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Nuclear Experiment
CBM physics program and recent experimental developments
CBM Collaboration
The Compressed Baryonic Matter (CBM) fixed-target experiment is under construction at the Facility for Antiproton and Ion Research. It aims to explore the phase structure of strong interaction (QCD) matter at high net-
baryon densities and moderate temperatures using heavy-ion collisions in the center-of-mass energy range per nucleon pair $\sqrt{s_{\mathrm{NN}}} =$ 2.7–4.9\,GeV. Equipped with fast and radiation-hard detector systems and an advanced triggerless data acquisition scheme, CBM will collect data at interaction rates of up to 10 MHz by performing online reconstruction and event selection. This will facilitate measurements of rare probes not accessible so far in this energy range, including multi-strange
hadron production and their flow coefficients, high-order net-
baryon cumulants, dileptons, as well as production of double-strange hypernuclei. The CBM detector is outlined and selected physics performance results based on realistic simulations are discussed.
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Applied Physics · Cross-listed from stat.AP
Calibrating the Brody exponent as a quantitative measure of short-range exclusion in 2D spatial point processes
Dawid Kucharski
The Brody distribution, originally a phenomenological interpolation between Poisson and Wigner level-spacing statistics in
quantum chaos, is calibrated here as a quantitative measure of short-range exclusion in 2D spatial point processes. Two results form the core. First, the 2D complete-spatial-randomness baseline is recalibrated to $\beta=0.96\pm0.15$, correcting the inappropriate 1D Poisson reference. Second, an empirical $\beta$–$r_{\text{excl}}$ calibration is validated against the effective hard-core radius with Spearman $\rho=0.988$. The framework is demonstrated on 58 manufactured surfaces (10 materials, 10 processes), phase-extracted interferometric profilometry of a certified roundness standard, and 2D binary
embeddings of
prime numbers. A sparse-integer control proves the
prime $\beta=2.15$ signal is genuinely arithmetic ($\Delta\beta=+0.68$ over random-integer control), while a Cantor-
embedding null result ($\beta=1.40$, TOST $p<0.01$) demonstrates that 2D exclusion is
embedding-created rather than intrinsic. Density-thinning experiments establish that $\beta$ captures exclusion strength rather than point density, while absolute values are density-dependent. A distinct CSR baseline for binary fields at low fill fraction is identified, with a decision table provided. The $\beta$–$r_{\text{excl}}$ calibration, the CSR baseline correction, and the control protocols together constitute a calibrated measurement framework for reproducible characterisation of short-range exclusion in 2D spatial point processes.
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Soft Condensed Matter
Effect of a Cone Shape on the Motion of Active Janus Colloids
Zhiyuan Zhao, Teun W.J. Verouden, Dillip K. Mohapatra et al. (+2 more)
The propulsion of active colloids is governed by their
symmetry and shape, yet a systematic investigation of how small
geometric effects influence the locomotion of anisotropic active colloids is lacking. In this paper, we study the effect of a cone shape by combining high-resolution two-
photon polymerization 3D printing with AC electric field experiments to study anisotropic Janus micro swimmers. We fabricate a series of Janus colloids with different shapes, ranging from a sphere to a hemisphere with a cone-protrusion, but containing similar hemispherical gold-coatings. Under an applied alternating current (AC) electric field, all particles exhibit active, ballistic motion. We find a shape and size dependence on the propulsion velocity, with the spherical Janus particle moving fastest, followed by a small cone and a large cone protrusion, while surprisingly a printed sphere with a flat side moves slowest. In addition, a reversal in the direction of motion for all shapes was triggered, a phenomenon governed by a transition from induced-charge electrophoresis (ICEP) at low frequencies to self-dielectrophoresis (sDEP) at high frequencies. We reveal a distinct shape influence, with the large cone-protrusion increasing their velocity in the sDEP regime. Our results provide insight into the link between active particle geometry and their propulsion velocity that are important for understanding biological micro swimmers and designing optimized microrobots.
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All authors Zhiyuan Zhao, Teun W.J. Verouden, Dillip K. Mohapatra, Evert M.E. Simons, Janne-Mieke Meijer
Fluid Dynamics
Engine position effects on contrail evolution for a realistic aircraft configuration
Rémy Annunziata, Nicolas Bonne and François Garnier
This study investigates the influence of representative engine positions on contrail
evolution during the
vortex and dissipation regimes, using three-dimensional simulations of a realistic aircraft geometry. Large Eddy Simulations are employed, coupled with an Eulerian microphysical bulk model, and initialized using fields obtained from prior Reynolds-Averaged Navier-Stokes simulations. This approach enables a consistent transition from near-field jet-
vortex interactions to far-field wake dynamics. Three engine placements are examined under two atmospheric stratifications and two relative humidity conditions. The results reveal that engine position influences the onset and
evolution of
vortex instabilities, alters the descent of the
vortex pair, and leads to slight changes in the distribution of particles within the wake. Despite these aerodynamic differences, the microphysical properties of the contrails tend to converge over time for the parameters and configurations covered in this study. From a broader perspective, engine placement strongly influences initial contrail formation and early
vortex-regime dynamics. At later stages, these differences largely disappear, as
vortex dynamics and atmospheric conditions dominate over the initial dilution changes induced by engine position.
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Materials Science
Melt-Quench Failures and Practical Solutions for Universal Machine-Learning Interatomic Potentials in Amorphous Structure Generation
Shuwei Li, Yuqi An, Xingyu Guo et al. (+2 more)
Generating experimentally relevant amorphous structures via melt-quench molecular dynamics is prohibitively expensive at the first-principles level. Universal machine-learning interatomic potentials (uMLIPs) could accelerate such simulations, but their reliability under non-
equilibrium conditions remains unclear. Here, we examine eight leading uMLIPs for generating amorphous IrO2, using this electrocatalytically relevant
oxide as a diagnostic case. Under the conventional melt-quench protocol, all models yield unphysically expanded structures with densities of 1-4 g/cm3, far below the ab initio molecular dynamics (AIMD) reference value of 10.04 g/cm3. Comparisons against ab initio references show that accurate energies and forces alone do not ensure stable NPT dynamics; correct energy-volume responses and pressure predictions are also essential. We identify two practical remedies: pressure-targeted fine-tuning and a revised NVT-quench/NPT-equilibration protocol that avoids unphysical volume expansion without additional ab initio training data. Both recover IrO2 densities and local structures consistent with AIMD. Across 30 chemically diverse materials, the volume-expansion failure proves general, and the revised protocol substantially improves density predictions, reducing the AIMD-referenced MAE from 2.46 to 0.35 g/cm3. This work establishes practical validation criteria and simulation strategies for robust uMLIP-driven amorphous structure generation.
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All authors Shuwei Li, Yuqi An, Xingyu Guo, Wenqiang Yang, Zhenbin Wang
General Relativity and Quantum Cosmology
Generalized Unimodular Gravity and Cosmological Perturbations
Júlio C. Fabris and Alexander Yu. Kamenshchik
The generalized unimodular theory is revisited and its consequence for cosmology is discussed. The usual matter components of the universe are obtained in a pure
geometric way. This result gives a new perspective to the studies of the dark sector of the universe. A background and perturbative analysis are carried out, recovering the corresponding results obtained through the general relativity theory but with a different interpretation.
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High Energy Physics (Phenomenology)
Static linear response of hot and dense QCD matter to electromagnetic fields: Leading hard and soft QCD corrections
Osvaldo Ferreira, Eduardo S. Fraga, Tyler Gorda et al. (+3 more)
We compute the static electromagnetic susceptibilities of a hot and dense
quark-
gluon plasma using perturbative
Quantum Chromodynamics (QCD). Our evaluation includes the leading $\mathcal{O}(\alpha_s)$ correction as well as the leading soft, resummed contribution of $\mathcal{O}(\alpha_s^{3/2})$ within electrostatic QCD. By matching to
Lattice QCD at vanishing
baryon chemical potential through
Lattice perturbation theory, we establish a connection between perturbative results and
Lattice simulations and assess the size of higher-order corrections. This extends the electromagnetic susceptibilities to finite
baryon chemical potential, where
Lattice methods are not applicable and establishes first-principle constraints on the
quark-
gluon plasma's electromagnetic response at temperatures and densities relevant for intermediate-energy heavy-ion collisions.
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All authors Osvaldo Ferreira, Eduardo S. Fraga, Tyler Gorda, Risto Paatelainen, Leon Sandbote, Kaapo Seppänen
Quantum Physics
Scalable Graph State Generation with O(1) Local Feedforward in Quantum Networks
Xiaoyi Zheng, Chan-Tong Lam, Lin Chen et al. (+1 more)
The development of
quantum networks faces a key challenge: the contradiction between probabilistic long-range
entanglement generation and finite coherence time. Existing routing protocols typically focus on global state computation or path optimization. As the network scales up, classical delays accumulate and exacerbate decoherence, leading to a decrease in
entanglement fidelity. To reduce routing decision delays to levels far below the coherence time of
qubits, we propose a protocol based on local measurement and classical feedforward. This protocol reduces the local decision complexity to amortized O(1) level, ensuring that the decision delay is always much smaller than the coherence time of
qubits. We map this protocol onto a dual-species trapped-ion platform and perform hybrid simulations. The results show that the proposed protocol performs well in terms of both resource efficiency and time feasibility. Noise analysis indicates that readout fidelity is the main bottleneck of this protocol, but noise suppression can be achieved by employing an erasure transformation in the dual-species architecture, combined with spatial multiplexing and branch independence, thereby ensuring the generation of high-fidelity
star subgraphs. This protocol provides a clear path to achieving high-fidelity
star subgraphs. These subgraphs can serve as general modules, merging to construct arbitrary subgraphs, providing a feasible solution for future fault-tolerant distributed
quantum computing.
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All authors Xiaoyi Zheng, Chan-Tong Lam, Lin Chen, Zheng Xing
Optics
Optomechanical parametric control of mid-infrared photons via molecular vibrational polariton
Ryoko Sakuma, Koji Sakai, Hajime Okamoto et al. (+2 more)
Controlling mid-infrared (MIR)
photons using well-developed telecom photonic platforms would enable new functionalities in molecular and
quantum photonics. However, establishing efficient interactions between MIR and telecom
photons remains challenging due to their large spectral separation and weak nonlinear coupling. Here, we demonstrate optomechanical control of MIR
photons mediated by vibrational polaritons, enabling
photon-
photon interaction between MIR and telecom fields across distant spectral regions. Using a Fabry-Pérot cavity incorporating a vibrationally active
polymer, we observe telecom-driven dissipation enhancement of MIR
photons at 9.5 $\mu$m with a modulation depth of 1% under a 4 mW pump. The linear power dependence, mixing-ratio dependence, and detuning response consistently indicate a MIR and telecom
photon-
photon conversion enabled by strong light-matter coupling. This approach establishes a polaritonic optomechanical platform for bridging disparate spectral regimes and provides a dissipation-engineered route toward hybrid MIR photonics and
quantum transduction.
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All authors Ryoko Sakuma, Koji Sakai, Hajime Okamoto, Motoki Asano, Hiroshi Yamaguchi
High Energy Physics (Phenomenology)
Liwei Liu, Xiqing Hao, Dianwei Wang et al. (+2 more)
Considering two-
fermion $F_a F_b$ productions and decays via one scalar or
photon exchange at the $e^+e^-$
collider, we show that the rank $r_{\rho}$ of
spin density
matrix $\rho$ is equal to the number of degrees of freedom of the mediator. For one generic scalar exchange, the
spin density
matrix is rank one for a pure state. With rank-one condition, we can determine the
spin analyzing powers for $F_a$ and $F_b$ and their product if the CP
symmetry is violated and conserved, respectively, and probe the CP violation. These results can be applied to the $\eta_c \to \Lambda {\bar \Lambda}$ at the BESIII experiment and the
Higgs $\to \tau \tau $ at the LHC. For one
photon exchange, the
spin density
matrix is rank two for a mixed state. Considering the $\Lambda \bar \Lambda $ productions and decays at the BESIII experiment as an example, we show that the
spin analyzing powers for $F_a$ and $ F_b$ can be determined by the rank-two conditions in details. Therefore, we can reconstruct the
spin density
matrices, probe the
quantum entanglement and Bell non-locality, and evade the no-go
theorem. Furthermore, we
conjecture that the $N\times N$
spin density
matrix with $r_{\rho} \le N-2 $ can be reconstructed at the
lepton colliders in general.
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All authors Liwei Liu, Xiqing Hao, Dianwei Wang, Lina Wu, Tianjun Li
Plasma Physics
The Effect of Anomalous Resistivity on Tearing Instability
D. Tsiklauri
We study the modification of classical tearing instability due to anomalous resistivity by incorporating a variable, second-order resistivity model into the resistive magnetohydrodynamics (MHD) framework. We evaluate the resulting {weakly non-linear boundary-layer scaling laws under a localized current-feedback mechanism}. By extending the {inner-layer analysis to capture localized current feedback}, we resolve localized spatial singularities ($\delta$ and $\delta'$) at the threshold boundary. These singularities generate unexpected matching jump conditions, demonstrating an early-stage phase-slip layer that forces a
hyperbolic, time-dependent growth rate divergence prior to macroscopic saturation. Physical estimates for fusion devices and
solar flares prove that this {consistent weakly non-linear matching formulation} triggers an abrupt transition into the explosive reconnection regime, offering an exact analytical resolution to the long-standing
solar and tokamak
flare/disruption “trigger problem,” respectively. Finally, a comparative analysis using a truncated linear expansion of the threshold model regularizes the singular behavior, confirming that the explosive finite-time singularity is uniquely driven by the higher-order non-linear current feedback.
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Astrophysics of Galaxies
The gas kinematics in 70 {\mu}m dark molecular clumps with ammonia
Chao Ou, Shanghuo Li, Junzhi Wang et al. (+5 more)
We present the investigation of the gas kinematics and assess the evolutionary stages of dense cores embedded in four infrared dark clouds (IRDCs) using the NH$_3$(1,1) and NH$_3$(2,2) lines obtained from the VLA and GBT observations. There is no 1.3 cm continuum emission counterpart in 1.3 mm continuum emission revealed by the SMA toward these IRDCs. The low production rate $N_{\rm uv} \sim 10^{44}$ s$^{-1}$ of Lyman continuum
photons, indicates that the four IRDCs are in very early evolutionary stages, in which free–free emission is still absent. We have identified 61 dense cores at the size scale of $\sim$0.1 pc using the inner satellite groups of NH$_3$(1,1) line. Among them, 38 dense cores exhibit a single velocity component, while 23 dense cores show multiple velocity components. We find that the nonthermal velocity dispersion ($\sigma_{\mathrm{non}}$) increases with increasing radial distance from the center of dense core within the inner 0.1 pc toward eight dense cores, indicating that the
turbulence is likely dissipated toward the center of these dense cores. In addition, two dense cores in AGAL031.024+00.262 and one core in AGAL024.314+00.086 exhibit nearly sonic motions on a small scale of 0.01 pc. The weakening of nonthermal support against
gravity suggests that these dense cores are close to gravitational collapse or are already collapsing. Conversely, there are seven dense cores in AGAL031.024+00.262 showing a decrease in $\sigma_{\mathrm{non}}$ with increasing radial distance from the center. By comparing this trends with the
outflow revealed by CO J=2-1 line, we find that these cores are likely associated with embedded
star formation activities. Higher angular resolution observations on sub-parsec scales are essential to reveal the transition from thermal to nonthermal-dominated regions, especially in dense cores associated with multiple velocity components.
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All authors Chao Ou, Shanghuo Li, Junzhi Wang, Yuqiang Li, Shuting Lin, Ian W. Stephens, Qizhou Zhang, Bo Zhang
Instrumentation and Detectors
Hit-rate capability of a silicon strip detector module for decay positron detection in the J-PARC muon $g-2$/EDM experiment
Ryuto Azuma, Katsunori Awa, Shunsuke Doi et al. (+34 more)
In the J-PARC
muon $g-2$/EDM experiment, a silicon strip detector will be used to detect positrons from
muon decays. The detector consists of planes of detector modules arranged radially. The expected maximum hit rate reaches 1.4~MHz per sensor strip, and achieving high detection efficiency even under such hit-rate conditions is a key performance requirement. We have developed the smallest unit of the detector module, and its performance was evaluated using a
muon beam at the J-PARC MLF H-line. The specifications of the detector module and the evaluated hit-rate capability are described in this article.
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All authors Ryuto Azuma, Katsunori Awa, Shunsuke Doi, Yowichi Fujita, Seiso Fukumura, Yu Goto, Ryotaro Honda, Sohtaro Kanda, Tetsuichi Kishishita, Tatsuya Kume, Tsutomu Mibe, Yukiharu Murata, Shoichiro Nishimura, Shinji Ogawa, Yuta Okazaki, Naohito Saito, Maki Sakakibara, Osamu Sasaki, Taiki Sato, Yutaro Sato, Yoshiaki Seino, Hiroshi Sendai, Koichiro Shimomura, Shohei Shirabe, Masayoshi Shoji, Patrick Strasser, Taikan Suehara, Shiori Sugahara, Junichi Suzuki, Toshikazu Takatomi, Manobu M. Tanaka, Junji Tojo, Hiroyuki A. Torii, Takashi Yamanaka, Hiroshi Yamaoka, Takayuki Yamazaki, Tamaki Yoshioka
Materials Science · Cross-listed from cs.CE
Phase-field analysis of fracture in heterogeneous wellbore systems: effects of casing eccentricity and cement-formation interface strength
Tharunsarathy Sachithanantham, Wasim Niyaz Munshi, Chandrasekhar Annavarapu et al. (+1 more)
Predicting the initiation and propagation of cracks in heterogeneous wellbore systems under complex in-situ conditions remains challenging. We present a hybrid phase-field fracture framework to model crack growth in heterogeneous wellbore systems with weak interfaces. The framework is first validated against
benchmark problems with available analytical and numerical solutions. Subsequently, numerical experiments are conducted to isolate the effects of interface strength and casing eccentricity on crack growth. The results show that casing eccentricity strongly influences both the pressure at crack initiation and the resulting crack paths, reducing the crack initiation pressure by up to 30% relative to the concentric configuration. For the examples considered here, beyond a critical eccentricity threshold of 50%, localized shear stresses drive the nucleation of inclined cracks in the rock formation in addition to radial cracking – a failure mode absent in concentric configurations. For sufficiently weak interfaces (i.e., interfaces with 30% of the toughness of the surrounding bulk material), radially propagating cracks in the cement sheath are deflected along the interface rather than penetrating into the rock formation. This deflection delays stress relaxation within the sheath, promotes the nucleation of additional radial cracks, and increases the risk of sustained casing pressure and wellbore failure. Finally, a three-dimensional simulation reveals depth-dependent crack nucleation, stress-shadow effects that suppress full-depth crack growth, and crack coalescence along the cement-rock interface – phenomena that are fundamentally inaccessible under plane-strain assumptions – demonstrating the applicability of the framework to realistic heterogeneous wellbore systems.
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All authors Tharunsarathy Sachithanantham, Wasim Niyaz Munshi, Chandrasekhar Annavarapu, Birendra Jha
Astrophysics of Galaxies
Optical Variability as a Probe of Hidden Nuclear Activity in Type 2 AGNs
Maša Lakićević
Optical variability in Type 2 active
galactic nuclei (AGNs) is rarely explored because the direct
accretion-disk continuum is obscured by circumnuclear
dust. Nevertheless, detectable optical variations are present in multi-epoch surveys such as SDSS Stripe~82, indicating that some component of the
nuclear emission is observed indirectly, for example through scattering or partial transmission. This study explores whether this variability is statistically connected to spectroscopic parameters of the narrow-line region (NLR), using the ALPAKA catalogue of spectral measurements. A subsample of 412 Type 2 AGNs was assembled by crossmatching SDSS Stripe 82 multi-epoch variability measurements in the $u,g,r,i,z$ bands with the ALPAKA spectroscopic catalogue. Correlations were then computed between the root-mean-square (RMS) variability amplitudes and the corresponding emission-line luminosities, kinematic widths and equivalent widths (EWs). Significant anti-correlations are found between the RMS amplitudes and [O III] 4949, [O III] 5007, [N II] 6548 and [NII] 6584 line luminosities. Velocity dispersions ($\sigma$) and EWs of forbidden-lines [O III] 5007 and [N II] 6584 also show moderate anti-correlations with RMS. The results demonstrate that even in obscured AGNs, optical variability carries information about the hidden
nucleus. The anti-correlation between RMS and line luminosity suggests a connection between
accretion stability and ionising output. Anti-correlations between RMS and the [O III] and [N II] velocity dispersions indicate a secondary correlation between optical RMS variability and the integrated kinematic state of the NLR. In addition, the anti-correlation between RMS and EW shows that the EW variations are primarily driven by changes in the continuum level, while the narrow-line flux itself remains effectively constant on the relevant timescales.
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Geophysics
Resonant lunar tides of Earth's core and basal magma ocean
Murray B.C. Kiernan, Hamish C.F.C. Hay, David W. Rees Jones et al. (+2 more)
Earth's
magnetic field is generated by fluid motion in the
liquid-metal core and has been active for billions of years. However, prior to the onset of inner-core growth, the sources of mechanical power that drove the geodynamo remain uncertain. During this period, the core may have been overlain by a basal magma ocean (BMO), creating two immiscible fluid layers separated by a density interface, beneath the solid mantle. We develop a theory for lunar tides in this core–BMO system, in which the
tidal potential acts on the density contrast between the two layers. The resulting dynamics differ fundamentally from previous models driven by imposed deformation of the core's bounding envelope. In the inviscid limit, the response transitions from an
equilibrium tide to an interfacial
gravity wave as forcing frequency increases. The two regimes are separated by a resonance that occurs when the forcing frequency matches the natural frequency of the degree-2, order-2 interfacial mode. The inviscid core flow is formally identical to the canonical elliptical
vortex, linking the problem to the theory of elliptical instability. Finite viscosity regularises the resonance, introduces phase lag and generates oscillatory boundary layers. Combined with parameterised models of lunar recession and BMO crystallisation, the theory predicts enhanced core-boundary ellipticity, core-flow speed,
magnetic Reynolds number and instability metrics, particularly near resonance. These results identify a previously unexplored mechanism for tidally driven flow in differentiated planetary bodies and show that a BMO can enhance
tidal coupling to the core, potentially contributing to dynamo action.
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All authors Murray B.C. Kiernan, Hamish C.F.C. Hay, David W. Rees Jones, James F.J. Bryson, Richard F. Katz
Statistical Mechanics
Thermodynamic Uncertainty Relation For a Multi-Phase Alternating Renewal Random Walk
Fatemeh Karimi and Farhad H. Jafarpour
Thermodynamic Uncertainty Relations (TURs) impose universal bounds linking current precision to
entropy production in nonequilibrium systems. While general bounds like the Proesmans–Van den Broeck (PV) relation provide a broad framework, they often remain loose for processes characterized by renewal events. In this work, we derive a generalized entropic bound for current fluctuations in renewal-reward processes. By utilizing a rigorous variance decomposition within the framework of renewal-reward theory, we obtain a model-independent bound that is not only rigorous but tighter than the standard PV relation. Notably, in the linear-response regime, our bound correctly scales with the renewal rate and identifies a precision penalty arising from cycle-length fluctuations. These results provide a physically informative constraint on the precision of run-and-tumble-type dynamics and highlight the universal limits of transport in complex
stochastic walkers.
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Superconductivity
Non-stationary longitudinal Josephson effect in electron-hole bilayers
O.M. Konstantynov and S.I. Shevchenko
The non-stationary longitudinal Josephson effect in
bilayer systems with pairing of spatially separated electrons and holes is investigated. The tunneling current between two (right and left) weakly coupled electron-hole condensates is analyzed in the presence of an external voltage applied along the layers. Two limiting regimes are considered: the high-density regime, where pairing occurs in momentum space similarly to conventional
superconductors, and the low-density regime corresponding to a Bose-Einstein condensate of spatially indirect
excitons. Using the tunneling
Hamiltonian approach, expressions for the quasiparticle, superconducting and interference contributions to the tunneling current are derived. It is shown that in the high-density limit the quasiparticle and interference currents vanish at zero temperature below a threshold voltage determined by the energy gap, so that only the supercurrent remains. In contrast, in the low-density regime the gapless spectrum of collective excitations leads to finite dissipative contributions even at zero temperature, resulting in damping of Josephson oscillations. For spatially separated tunneling barriers with distance exceeding the coherence length, phase jumps occur at each barrier, resulting in voltage oscillations across the electron and hole barriers and a non-sinusoidal current-phase relation governed by the critical currents of the two barriers.
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