Peer Revenue Publish or profit

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics

Watch Physics

Thursday 3 September

Soft Condensed Matter

Effects of Charge Regulation on the Conformations and Dynamics of a Polyelectrolyte during Nanoparticle Adsorption

Kawaljeet Kaur, Rashmi Kandari, Sunita Kumari et al. (+1 more)

Customizing the surface characteristics and stimuli-responsive behavior of polyelectrolyte (PE) during interaction with nanoparticles (NP) have potential applications ranging from biological interactions to advanced diagnostic technologies. Using numerical simulations, we investigate how charge regulation (CR) shapes the conformation, dynamics and adsorption of PE on a oppositely charged NP and compared the results with constant charge (CC) conditions. At low solvent ion concentrations, CR barely affects the adsorption fraction, while significantly enhancing the dynamical response of the PE. However, at high ion concentrations, while complexation is suppressed in the CC case, the CR environment helps to overcome the energy barriers related to Debye screening and thermal fluctuations, thereby promoting the adsorption. By maintaining the strong PE-NP electrostatic interaction, PE exhibits a more directed ballistic-like dynamics towards NP during adsorption, in comparison to the diffusive and sub-diffusive behavior observed in the CC case. Our results emphasize that in high ion concentrations, with a strong Debye screening effect, a small fraction of charge-fluctuating sites suffices for adsorption to happen. A tunable CR mechanism is thus an efficient and robust strategy to control the biomolecular interaction and stability in complex environments.
Read the full abstract

All authors Kawaljeet Kaur, Rashmi Kandari, Sunita Kumari, Subhajit Paul

Quantum Physics

Optimizing Atom Transport, Gate-Count and Depth with Parity Twine

Javad Kazemi, Michael Fellner, Riccardo J. Valencia-Tortora et al. (+2 more)

We present an efficient implementation of the Parity Architecture for neutral-atom quantum processors. We adapt Parity Twine Networks (PTNs) to different atom layouts, native entangling gates, and atom-shuttling capabilities. This provides a general framework for hardware-aware optimization of gate count, circuit depth, and atom transport for quantum circuits encoding arbitrary interaction graphs in a common basis. Specifically, we develop PTN constructions based on different native entangling-gate realizations, namely CZ, CZSWAP, and iSWAP, providing flexibility to accommodate different hardware capabilities on both static and mobile neutral-atom platforms. Using the quantum Fourier transform (QFT) as a representative example, we demonstrate substantial reductions in two-qubit gate count, atom transport, and circuit depth. These resource savings translate into an estimated circuit fidelity three orders of magnitude higher than competing compilation strategies for a 30-qubit QFT. We further extend the construction to the recently introduced optimistic QFT and discuss the broader applicability of PTNs to other quantum algorithms on neutral-atom platforms.
Read the full abstract

All authors Javad Kazemi, Michael Fellner, Riccardo J. Valencia-Tortora, Michael Schuler, Wolfgang Lechner

Data Analysis and Statistics

The Greedy Bump Bias: Local Profiling Geometry and the Look-Elsewhere Effect

Tommaso Dorigo

When fitting a localized signal whose position or shape is not known in advance, one typically allows these parameters to vary together with the signal amplitude and chooses the values that maximize the likelihood. This freedom has two related statistical consequences. If a genuine signal is present, its fitted amplitude will be affected by a positive bias; otherwise, the same freedom increases the chance of finding an unusually signal-like background fluctuation, giving rise to the look-elsewhere effect. We show that these two effects can be understood as consequences of the same local geometry of the family of signal templates. We study this connection in a Gaussian matched-filter model, where a smooth D-dimensional family of normalized templates describes the unknown signal location or shape. In the normalized matched-filter problem, the curvature of a genuine signal peak and the fluctuations that determine the curvature of a high background peak are governed by the same template metric. This allows us to derive an explicit asymptotic relation. We then follow the problem away from the strong-signal and high-threshold limits. Separating the signal-associated maximum from the best competing maximum gives an exact decomposition of the global bias into a local profiling contribution and a contribution from remote-peak competition. In a one-dimensional Gaussian example, the second factorial cumulant accounts for most of this correction, while the third brings the prediction into close agreement with simulation. A two-point Kac–Rice calculation reproduces the second cumulant and reveals a quartic short-distance suppression of nearby maxima. The resulting picture separates the roles of local dimension, model-dependent curvature, and global extremal competition within a common framework.
Read the full abstract

Nuclear Experiment

First Measurement of Near-Threshold J/{\psi} Photoproduction on the Neutron

R. Tyson, D.G. Ireland, B. McKinnon et al. (+139 more)

We report the first measurement of the total and t-differential cross sections for near-threshold J/$\psi$ photoproduction on the neutron, obtained with the CLAS12 detector at the Thomas Jefferson National Accelerator Facility. The measurements, performed using a liquid-deuterium target, also provide the incoherent total and t-differential cross sections on the bound proton, enabling the first direct comparison of near-threshold J/$\psi$ photoproduction on bound protons and neutrons. Interpreted within Vector Meson Dominance, holographic QCD, and GPD-based frameworks, the data allow for the investigation of the gluonic structure of bound nucleons. A comparison with free proton results reveals hints of modifications to the gluon structure of nucleons in the nuclear medium, within the assumptions of the extraction and on the underlying production mechanism. The comparison of bound neutron and bound proton cross sections provides new constraints on the near-threshold J/$\psi$ production mechanism, which is crucial in order to establish J/$\psi$ photoproduction as a probe of the nucleon's gluonic structure.
Read the full abstract

All authors R. Tyson, D.G. Ireland, B. McKinnon, P. Chatagnon, V. Kubarovsky, S. Stepanyan, A.G. Acar, P. Achenbach, J.S. Alvarado, M.J. Amaryan, W.R. Armstrong, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, F. Benmokhtar, A. Bianconi, A.S. Biselli, A. Biswas, M. Bondi, F. Bossù, S. Boiarinov, K.-Th. Brinkmann, W.J. Briscoe, W.K. Brooks, J Bryce, N.L. Bucuru, S. Bueltmann, V.D. Burkert, T. Cao, D.S. Carman, A. Celentano, H. Chinchay, G. Ciullo, E.W. Cline, P.L. Cole, M. Contalbrigo, A. D'Angelo, N. Dashyan, R. De Vita, A. Deur, S. Diehl, C. Dilks, C. Djalali, R. Dupre, H. Egiyan, M. Ehrhart, A. El Alaoui, L. El Fassi, L. Elouadrhiri, C. Fanelli, M. Farooq, S. Fegan, I.P. Fernando, E. Ferrand, A. Filippi, C. Fogler, S. Frantzen, K. Gates, G.P. Gilfoyle, D.I. Glazier, R.W. Gothe, Y. Gotra, S. Gramigna, B. Gualtieri, K. Hafidi, H. Hakobyan, M. Hattawy, F. Hauenstein, T.B. Hayward, D. Heddle, T. Hellstern, M. Hoballah, M. Holtrop, Y. Ilieva, E.L. Isupov, H.S. Jo, S. Joosten, M. Kerr, H.T. Klest, V. Klimenko, A. Kripko, C. Lama, L. Lanza, S. Lee, P. Lenisa, D. Martiryan, V. Mascagna, M. Masud, A. Mehta, R.G. Milner, R. Milton, M. Mirazita, V. Mokeev, E.F. Molina Cardenas, C. Munoz Camacho, P. Nadel-Turonski, T. Nagorna, K. Neupane, S. Niccolai, M. Osipenko, P. Pandey, M. Paolone, L.L. Pappalardo, R. Paremuzyan, E. Pasyuk, C. Paudel, S.J. Paul, L. Polizzi, J. Poudel, Y. Prok, A. Radic, K. Ramage, M. Ripani, M Ronayette, P. Rossi, A.A. Rusova, S. Schadmand, A. Schmidt, Y.G. Sharabian, E.V. Shirokov, S. Shrestha, E. Sidoretti, N. Sparveris, I.I. Strakovsky, S. Strauch, M. Tenorio, F. Touchte Codjo, M. Ungaro, S. Vallarino, C. Velasquez, L. Venturelli, H. Voskanyan, E. Voutier, Y. Wang, D.P. Watts, U. Weerasinghe, X. Wei, N. Wuerfel, Z. Xu, Z.W. Zhao, M. Zurek

Materials Science

High-Throughput Computational Discovery of Inverted Resistive Switching in Two-Dimensional Materials

Sanchali Mitra, Arnab Kabiraj, Benjamin W. J. Chen et al. (+8 more)

Atomristors, non-volatile resistive switching devices based on two-dimensional (2D) monolayers, are promising building blocks for energy-efficient memory and neuromorphic computing. However, their design remains restricted to a few materials such as MoS2 and h-BN, limiting functional diversity and design flexibility. Here, a high-throughput computational framework combining density functional theory, machine-learning molecular dynamics, and quantum transport simulations screens about 2,900 exfoliable monolayers for vacancy-mediated resistive switching, identifying 17 thermally stable candidates in two mechanistically distinct classes. In Class 1 monolayers, such as GaS, Au adsorption at the native vacancy introduces conducting states, switching the insulating monolayer from a high- to a low-resistance state (HRS-to-LRS). Class 2 monolayers, comprising ionically bonded metal oxyhalides and nitrohalides such as BiOCl, exhibit previously unreported inverted switching. Vacancy-released electrons delocalize and push the Fermi level into the conduction band, placing the device natively in the LRS; Au adsorption re-localizes these carriers and returns the Fermi level to the gap, driving LRS-to-HRS switching. Quantum transport simulations confirm both mechanisms, while migration-barrier calculations identify the electrode-2D separation as a key parameter governing Au migration and the resistance window. These findings expand the atomristor landscape and establish complementary switching as a design paradigm for multifunctional memory and neuromorphic hardware.
Read the full abstract

All authors Sanchali Mitra, Arnab Kabiraj, Benjamin W. J. Chen, Han Zhang, Haiyu Meng, Shi-Jun Liang, C. S. Lau, Lei Shen, Lain-Jong Li, Kah-Wee Ang, Yee Sin Ang

Materials Science

SALTED: a symmetry-adapted machine-learning program for predicting electron-densities in molecules and materials

Zekun Lou, Alan M. Lewis, Théophane Bernhard et al. (+5 more)

SALTED provides an open-source Python package for machine learning the quantum-mechanical electron density, $n(\mathbf{r})$, in molecular and condensed-phase systems based on input atomic coordinates and species. The program adopts a linear atom-centered decomposition of the electron density, which makes it highly transferable across diverse atomistic configurations sharing similar chemical environments. Because of this representation choice, SALTED is naturally interfaced with state-of-the-art electronic-structure programs based on atomic orbitals, namely CP2K, FHI-aims, and PySCF, from which reference electron-density data can be generated and used to train a model. The learning algorithm is based on a symmetry-adapted extension of Gaussian process regression, making SALTED especially efficient in small-data regimes. Thanks to the implementation of vector-field kernel functions, SALTED can also learn the first-order response of the electron density to applied electric fields, $\partial n(\mathbf{r})/\partial \mathbf{E}$. The application of SALTED within computational workflows has already shown its utility in a wide variety of contexts, including the calculation of polarization vectors and polarizability tensors, the accurate evaluation of Coulomb forces in QM/MM molecular-dynamics simulations, and electronic-structure studies of large-scale 2D materials.
Read the full abstract

All authors Zekun Lou, Alan M. Lewis, Théophane Bernhard, Lukas Seifert, Agustin Salcedo, Florian Kleemiss, Mariana Rossi, Andrea Grisafi

Earth and Planetary Astrophysics

Trans-Neptunian Object dynamics even better explained by a stellar flyby after 4.5 Gyr of evolution

Susanne Pfalzner, Frank W. Wagner and Marco Bischoff

The Trans-Neptunian objects (TNOs) formed together with the planets from a flat disc of gas and dust but now orbit the Sun mostly on inclined, eccentric orbits. One explanation for the TNOs' orbits is a close flyby of another star. One with a mass of $M_p =$0.8 Msun at $q_p =$ 110 au and $i_p =$70{\deg} fits the observations. However, such close encounters were more frequent when the Sun was young and still part of its birth cluster. Assuming that the flyby happened then, we use numerical $N$-body simulations to model how the TNOs' orbits changed due to interactions with the planets over the 4.56 Gyr since the Sun formed. We find that the cold Kuiper belt region lost about 80% and the hot Kuiper belt population about 40% of its initial population. About 7% –8% of the TNOs were injected into the planet region, but almost all (99%) were ejected afterwards. By contrast, the orbital parameters of distant Sedna-like objects ($q >$60 au) remained basically unchanged. Surprisingly, in sum, these changes improve the fit to the observed TNO population even more, strengthening the argument for a close flyby to the Solar System. The remaining differences concern the location of the cold population and the inclination distribution of the Sedna population. We discuss possible reasons and steps to resolve these issues.
Read the full abstract

Soft Condensed Matter

Heterogeneous collapse in thermoresponsive copolymer microgels varying molar composition

Jacopo Vialetto, Francesco Brasili, Letizia Tavagnacco et al. (+5 more)

Understanding the internal architecture of copolymer microgels is crucial for establishing how nanoscale polymer organization controls their stimuli-responsive behavior. Here we focus on thermoresponsive P(N-isopropylacrylamide-co-N-isopropyl-methacrylamide), P(NIPAM-co-NIPMAM), microgels with varying mole fraction of the components, synthesized via radical precipitation polymerization, and we demonstrate that changes in their volume phase transition and equilibrium swelling are governed by composition-dependent internal heterogeneity. Comparison between small-angle neutron scattering (SANS) with isotopic labeling and monomer-resolved simulations show a block-like monomer distribution of the two components. SANS analysis reveals a universal maximum in the polymer mesh correlation length near the transition, evidencing coexistence of collapsed NIPAM-rich and swollen domains. The correlation length increases with increasing NIPMAM content, with a maximum for 75 mol % NIPMAM, implying sparse collapsed regions within the network and thus a large degree of heterogeneity induced by the presence of an increasingly large fraction of intercalated, non-collapsing PNIPMAM. The maximum heterogeneity correlates with the equilibrium swelling ratio, indicating that collapsed microgels retain a structural memory of the transition and present a less-compliant structure in response to temperature variations. Overall, these insights highlight a complex effect of the block-like monomer distribution on the responsive properties of copolymer microgels with different compositions, thus providing a design rule for tailoring responsive colloids for functional soft materials.
Read the full abstract

All authors Jacopo Vialetto, Francesco Brasili, Letizia Tavagnacco, Gavino Bassu, Elena Buratti, Stephen King, Emanuela Zaccarelli, Marco Laurati

Atomic Physics

Low stray-field ion pump configuration for cold atom experiments

Preeti Sharma, Luisa Loranca Cruz, Leonardo Ricci et al. (+1 more)

Ion pumps used in cold-atom experiments generate stray magnetic fields that can perturb magneto-optical trapping, shift Zeeman sensitive energy levels, and introduce systematic errors in precision spectroscopy. We numerically investigate a compact low-stray-field ion pump configuration designed to reduce magnetic flux leakage through the ultrahigh-vacuum port without increasing the overall pump size. Starting from a simplified magnetic model of a standard ion pump, we study two complementary modifications: auxiliary permanent magnets surrounding the original pump magnets with opposite magnetisation, and a soft-magnetic honeycomb field stopper integrated at the pump port. The resulting combined configuration strongly reduces the magnetic flux density outside the pump. In the geometry considered here, the field at 10 mm from the UHV port is reduced by 97.9%, while the calculated reduction in effective pumping speed due to the honeycomb stopper is 17.9%. These results indicate that engineered magnetic compensation and field-guiding structures can support more compact cold-atom vacuum systems while preserving pumping performance. Further work should validate the design with nonlinear magnetostatic modelling, molecular-flow simulations, and measurements on a complete pump geometry.
Read the full abstract

All authors Preeti Sharma, Luisa Loranca Cruz, Leonardo Ricci, Andrea Bertoldi

Earth and Planetary Astrophysics

Effect of stellar spot-only spectral lines in high-resolution transit spectroscopy

W. Dethier, E. Cristo, O. D. S. Demangeon et al. (+3 more)

We investigate how a representative single spectral line present only in a stellar spot can introduce distortions in high-resolution planetary absorption spectra. Specifically, we assess whether such spot-induced features may resemble planetary atmospheric absorption and the observational or stellar conditions under which they become significant. Using the SOAPv4 code, we simulated transit observations of an atmosphere-less planet across a star with a spot containing an additional absorption line compared to the photosphere's spectrum. Two systems were modelled: a close-in Jupiter-sized planet and a distant Earth-sized planet transiting a Sun-sized star. We varied the stellar rotation period and the spot size, and ensured that the planet transits the spot. Spectral lines were idealised Gaussians to isolate the impact of the spot-specific feature. We show that a single stellar spot line can generate spurious features in the absorption spectrum. These features contaminate the absorption spectrum in ways that may lead to misinterpretation if not accounted for. For Jupiter-sized planets with short transits, the features are mainly emission-like, but can nonetheless dampen a potential true atmospheric absorption signature. For Earth-sized planets with long transits, the distortion is mainly absorption-like and could be interpreted as planetary absorption. These results highlight the importance of accounting for stellar heterogeneity and activity in the analysis of high-resolution absorption spectra.
Read the full abstract

All authors W. Dethier, E. Cristo, O. D. S. Demangeon, J. P. Lucero, N. C. Santos, B. Tessore

Earth and Planetary Astrophysics

Dynamically favorable hosts for submoons around Jupiter and Saturn

Ryan Dahoumane, Valéry Lainey and Kevin Baillié

The long-term stability of small bodies orbiting natural satellites (submoons) in the Solar System has been previously investigated using an analytical approximation of a three-body problem, focusing mainly on tidal forces and neglecting other perturbations. This approach suggests that submoons around most of the regular satellites in the Solar System could be stable. However, no such object has been detected to date. In this work, we extend these previous results by numerically testing the survival of submoons around a large number of satellites of Jupiter and Saturn. Our goal is to rank the satellites of Jupiter and Saturn according to how dynamically favorable they are for submoon survival over the simulated timescales. For each regular or irregular satellite considered, we performed 130 separate N-body integrations, each containing one hypothetical submoon with a different initial semimajor axis and inclination. From the 1 Myr survival fractions, we rank the satellites according to their dynamical favorability for submoon survival over the simulated timescale. We find that, after 1 Myr, the satellites with the highest survival fractions (above 30%) are Iapetus ($\approx 37\%$), Titan ($\approx 35\%$), Rhea ($\approx 32\%$), Phoebe ($30\%$), Callisto ($\approx 34\%$), and Ganymede ($30\%$). Rather than providing absolute probabilities for the existence of submoons, these survival fractions identify the most dynamically favorable hosts. Iapetus, Titan, Rhea, Phoebe, Callisto, and Ganymede are the most dynamically favorable submoon hosts among the tested satellites.
Read the full abstract

Statistical Mechanics

Sample-specific rectification-like response in a boundary-driven exclusion process

Issei Sakai and Takuma Akimoto

We investigate the current response of a boundary-driven symmetric exclusion process with quenched site disorder. Hard-core particles hop symmetrically on a one-dimensional lattice with site-dependent rates and are injected and removed at the boundaries by two reservoirs of different densities. We approximate the steady-state density profile using a Galerkin projection at linear order and a mean-field closure at higher orders, and thereby obtain the current as a nonlinear function of the reservoir density difference. At linear order in the reservoir density difference, the current-response coefficient depends on the mean reservoir density $\rho$, in contrast to the homogeneous case. Through the linear-response relation, this dependence leads to an equilibrium current-fluctuation coefficient that is asymmetric under $\rho\rightarrow 1-\rho$. Beyond linear response, nonzero even-order current contributions break the antisymmetry of the current under reversal of the reservoir density difference, producing rectification-like behavior in individual disorder realizations. We further show that spatial-reflection symmetry of the equilibrium density profile rules out such behavior, so broken spatial-reflection symmetry of the profile is a necessary condition for rectification-like behavior. Within the present approximation, we further find that, for continuously distributed site disorder, rectification-like behavior occurs arbitrarily close to equilibrium for almost every disorder realization. At the ensemble level, however, the disorder-averaged current remains antisymmetric because the disorder ensemble is invariant under spatial reflection. These results provide a mechanism for rectification-like transport arising from sample-specific spatial heterogeneity rather than from an explicitly imposed directional asymmetry.
Read the full abstract

Mathematical Physics · Cross-listed from math.PR

An Effective SPDE Model for a Schrödinger Equation with a Fluctuating Magnetic Potential

Franco Flandoli, Reika Fukuizumi, Francesco Grotto et al. (+1 more)

We consider the Schrödinger equation for a charged particle in a randomly fluctuating external magnetic field and establish a singular perturbation limit in which the solution converges to a deterministic Schrödinger equation with Gaussian fluctuations. We propose a stochastic Schrödinger equation incorporating the behavior of both the deterministic average and the fluctuations and show that it has the same limiting behavior as the original model, while providing a simpler way to study the distribution of relevant observables.
Read the full abstract

All authors Franco Flandoli, Reika Fukuizumi, Francesco Grotto, Eliseo Luongo

Mesoscale and Nanoscale Physics

Spectral Function Method and Janus Quantum Numbers in Quasiperiodic Systems

Tian-Le Wu, Shi-Ping Ding, Miao Liang et al. (+2 more)

The absence of translational symmetry in quasiperiodic systems invalidates conventional band theory, posing the central challenge in the field. Building upon the incommensurate energy band (IEB) concept, we establish a unified spectral theory for quasiperiodic systems by introducing two key advances. First, we develop an efficient spectral function method that calculates $A(k,\omega)$ using a small truncated Hamiltonian matrix, bypassing full diagonalization. It converges via a distinctive successive locking of energy moments, yielding exact thermodynamic-limit results without finite-size scaling. Second, we introduce that quasiperiodic eigenstates possess Janus quantum numbers: a single eigenstate, continuously tracked across localization transitions, carries dual labels in momentum and real space, which naturally reduce to the familiar Bloch momentum and band index in the commensurate limit. Together with IEB, these advances constitute a “band theory” for quasiperiodic systems, enabling us to define, compute, and label states with the same facility as in periodic ones.
Read the full abstract

All authors Tian-Le Wu, Shi-Ping Ding, Miao Liang, Jing-Tao Lü, Jin-Hua Gao

Quantum Physics

Enhancing noise robustness in device-independent conference key agreement with asymmetric parity-CHSH inequalities

Makoto Ishihara, Wojciech Roga, Jonatan Bohr Brask et al. (+1 more)

Conference key agreement allows multiple remote parties to establish a shared secret key with information-theoretical security. In device-independent conference key agreement, security can be guaranteed with minimal assumptions on the devices used, provided that a violation of a Bell inequality is observed. However, implementations are extremely challenging because high detection efficiency is required to observe loophole-free Bell violations. Here, we enhance the robustness of device-independent conference key agreement by introducing a new family of multipartite Bell inequalities called the asymmetric parity-Clauser-Horne-Shimony-Holt (CHSH) inequalities. We derive a tight analytical lower bound on the conditional von Neumann entropy of the outcomes of one of the parties in a protocol based on this inequality, including noisy preprocessing. Using this bound, we analyze robustness to detection inefficiencies as well as local and global depolarizing noise. We show that the combination of the asymmetric parity-CHSH inequality and noisy preprocessing can significantly improve the robustness to imperfections.
Read the full abstract

All authors Makoto Ishihara, Wojciech Roga, Jonatan Bohr Brask, Masahiro Takeoka

Plasma Physics

$X$-dispersionless solver for electromagnetic and axion fields in a cylindrical particle-in-cell code

Xiangyan An, Min Chen, Yipeng Wu et al. (+3 more)

We develop a quasi-cylindrical direction-splitting (QDS) dispersionless Maxwell solver for the open-source EPOCH particle-in-cell framework. The method preserves the exact axial phase velocity for every retained azimuthal mode by advecting transverse transport variables with the $c\Delta t=\Delta x$ shift. Building on the same transport viewpoint, we formulate an axion solver that advances the Klein–Gordon equation and the axion-regenerated electromagnetic fields within the QDS solver, so that axion–photon coupling is handled self-consistently. Benchmarks demonstrate that the cylindrical QDS solver reproduces the standard Yee wakefield structure while removing the axial group-velocity error and reducing computational cost by orders of magnitude. In the resonant axion generation test via two-color laser mixing, the QDS solver eliminates the spurious vacuum source term and maintains phase matching, whereas the Yee solver suffers from rapid dephasing due to numerical dispersion. The proposed algorithm therefore enables quasi-3D simulations of axion–photon physics in laser-plasma interaction with dispersion-free laser transport.
Read the full abstract

All authors Xiangyan An, Min Chen, Yipeng Wu, Jianglai Liu, Zhengming Sheng, Jie Zhang

Other Condensed Matter

Magnetic Couplings in Half-Filled Bipartite Graphs

Georges Bouzerar

We break from perturbative frameworks to establish a non-perturbative generalization of magnetic exchange rules in half-filled bipartite networks. While historical models remain strictly tied to the debatable perturbation approach in the dilute limit and require the absence of zero-energy modes, our universal mechanism governs exchange interactions across arbitrary bipartite graphs. By bypassing traditional expansion bottlenecks, this framework provides an analytical predictive tool for magnetism in complex lattices, offering key design principles to engineer stable, long-range order in next-generation 2D spintronic devices
Read the full abstract

Nuclear Theory

Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed $0^+\rightarrow 0^+$ beta decays

Jakub Wysocki, Jan Miśkiewicz, Jagjit Singh et al. (+1 more)

The symmetry-conserving density functional theory (DFT)-based no-core configuration-interaction (DFT-NCCI) framework is applied for the first time to investigate the impact of configuration interaction (CI) on the Coulomb (isospin) impurity, $\alpha_{\rm C}$, in the ground and excited states of $^{10}$C, $^{10}$B, and $^{14}$N, as well as on the isospin-symmetry-breaking (ISB) correction to the superallowed $0^+ \rightarrow 0^+$ $\beta$ decay of $^{10}$C. We demonstrate, among other findings, that within the DFT-NCCI framework CI has a negligible effect on the ground-state isospin impurities, which are dominated by a single doorway state. In contrast, CI significantly modifies the impurities in excited states, including the isobaric analogue $I=0^+,\,T=1$ state in $^{10}$B. Hence, it also has a non-negligible impact on the ISB correction to the superallowed $\beta$ decay of $^{10}$C. Our calculations yield $\bar{\delta}_{\rm C}=0.45(4)\%$ when the Coulomb interaction is taken as the sole source of ISB, and $\bar{\delta}_{\rm ISB}=0.46(6)\%$ when short-range charge-symmetry-breaking (CSB) terms are included in addition. Hence, no statistically significant dependence of the ISB correction on the short-range CSB interaction is observed for this decay. Comparison with our previous results reveals a strong sensitivity to the nuclear symmetry energy, which governs the strength of the isospin-restoring force and whose value in finite nuclei remains difficult to constrain because of its intricate dependence on the momentum-dependent terms of the effective interaction.
Read the full abstract

All authors Jakub Wysocki, Jan Miśkiewicz, Jagjit Singh, Wojciech Satuła

Quantum Physics

Pulse-Controlled Topologically Protected Quantum Batteries

Jin Yang, Biao Xiong, Jibing Liu et al. (+4 more)

Quantum batteries have emerged as a promising new generation of energy-storage devices for powering quantum technologies. Long-distance charging is particularly attractive because it minimizes interference between the charger and the battery, thereby attracting considerable interest. Here, we propose a topologically protected long-distance charging protocol for quantum batteries based on a pulse-controlled superconducting qubit chain. By dynamically modulating the pulse-mediated couplings, we realize topologically protected energy transfer from the charger to the battery. We show that the charging process is free of energy backflow and remains robust against imperfections in pulse control. Moreover, the energy stored in the battery at the target time is fully extractable, and the protocol remains effective for relatively large system sizes. To further accelerate charging, we optimize the pulse shape and elucidate the underlying physical mechanism. Our pulse-controlled topological quantum battery protocol provides a versatile framework for implementing long-distance topological charging and establishes a theoretical foundation for designing optimal-control strategies to enhance quantum battery performance.
Read the full abstract

All authors Jin Yang, Biao Xiong, Jibing Liu, Houguo Yu, Dehua Liu, Feng Mei, Chuanjia Shan

Quantum Physics

Heralded one-, two- and three-photon states from waveguided parametric down-conversion

Borrero Landazabal Daniel and Laiho Kaisa

The manifold coincidences and singles counting provides a resource-saving quantum-optics analysis tool, since it is appropriate even in the presence of heavy experimental imperfections. Here, we prepare cross-polarized twin beams in the telecommunication wavelength range via parametric down-conversion in a periodically-poled KTiOPO$_4$ waveguide and herald photon-number states up to three photons. First, we show that the single-click probability is a versatile tool not only for extracting the state's mean photon number but also for sampling values of the moment generating function being the core behind any quantum optical state. Second, we measure values of the normalized factorial moments of photon number, $g^{(m)}_{\text{h}}$, up to the order $m = n+1$ for the heralded $n$-photon state. These normalized photon correlations provide an expedient method for examining the higher-order non-classicality of light by violating the condition $g^{(m+1)}_{\text{h}} \ge g^{(m)}_{\text{h}} \ge 1$.
Read the full abstract

Computational Physics

BU-MBAR: A hybrid solution strategy for the MBAR equations

Fabio Müller, Francesco Alesiani and Henrik Christiansen

The multi-state Bennett acceptance ratio (MBAR) equations combine the data collected under different thermodynamic conditions in a statistically optimal way. Due to their practical importance, several solution strategies have been devised to optimize the convergence of the resulting set of coupled equations. However, even with graphics processing unit (GPU) acceleration, the convergence of these methods can still be either unstable or slow. We propose a new approach where the equations are interpreted as the limit of infinitesimal bin width of the respective weighted histogram analysis method (WHAM). In the proposed binned-to-unbinned MBAR (BU-MBAR) method, the bin width is adapted dynamically to ensure a stable and efficient convergence to the asymptotic solution.
Read the full abstract

Soft Condensed Matter

Near-surface colloidal dynamics in jammed and slipping microgel suspensions

Masoodah Gunny, Frédérick Caetano, Matilde Bureau et al. (+4 more)

Jammed suspensions of soft microgel particles may exhibit slippage along smooth boundaries. Owing to their expected sub-micrometric dimensions, direct observations of dynamics within the near-surface layers supposed to be responsible for this slippage have been difficult to achieve. Here, we use total internal reflection fluorescence microscopy (TIRFM) to observe nanoparticle dynamics near glass/microgel-suspension interfaces. Indicating near-wall dynamic heterogeneity, velocity profiles for suspensions are nonlinear. These profiles tend to a constant slippage velocity at submicrometric distances from the wall, consistent with macroscopic wall slip measurements. Furthermore, nanoscale particle altitude distributions are strongly dependent on the slip velocity, revealing a dynamically-mediated and nanoscale particle-organisation effect. The collected observations give support for the existence of near-wall heterogeneity as a dominant mechanism contributing to microgel wall slip. Our work also opens new perspectives for the study of particle dynamics and organisation in complex interfacial environments.
Read the full abstract

All authors Masoodah Gunny, Frédérick Caetano, Matilde Bureau, Alexandre Vilquin, Marie Le Merrer, Joshua D Mcgraw, Catherine Barentin

Plasma Physics

Formation and interaction of two-dimensional electron-acoustic solitons and breathers in superthermal plasmas

Jayshree Mondal, Prasanta Chatterjee and Biswajit Sahu

The nonlinear evolution and mutual interaction of two-dimensional electron acoustic (EA) nonlinear structures in superthermal plasma environment are studied. The plasma model consists of inertial cold electrons, superthermal hot electrons described by kappa ($\kappa$) distribution, and stationary ions providing overall charge neutrality. Using the extended Poincaré-Lighthill-Kuo (PLK) reductive perturbation technique, a pair of two-sided Kadomtsev-Petviashvili (KP) equations governing right- and left-propagating EA solitary waves (EASWs) is derived. Exact analytical solutions of the KP equations, including single soliton, multisoliton, breather, and lump structures, are obtained via the Hirota bilinear method. The effects of key plasma parameters such as hot electron concentration, temperature ratio, and superthermality index on the characteristics of these nonlinear excitations are examined. Particular attention is devoted to the head-on collision dynamics between solitons, breather-soliton, and breather-breather interactions. The results reveal quasi-elastic collisions accompanied by phase shifts, transient amplitude modulation, and localized energy concentration, with clear distinctions between oscillatory and non-oscillatory mode interactions. The present study provides new insights into multidimensional electron acoustic wave (EAW) dynamics and energy redistribution mechanisms in superthermal space plasmas, with direct relevance to planetary magnetospheric environments such as Saturn's ring region.
Read the full abstract

Astrophysics of Galaxies

Bright star-forming galaxies naturally forming at z>10 in the Shark semi-analytic model

Claudia D.P. Lagos, Angel Chandro-Gomez, Chris Power et al. (+1 more)

The James Webb Space Telescope (JWST) has unveiled the existence of numerous z>10 bright ultraviolet (UV) galaxies, potentially challenging galaxy formation models in a Lambda Cold Dark Matter (LCDM) universe. Modifications to star formation and stellar feedback models have been suggested to alleviate the tension. However, the fundamental challenge is to design a galaxy formation model that simultaneously reproduces observations from z=0 to those at the highest redshifts. Here, we present predictions from the Shark semi-analytic model of galaxy formation, which is tuned to reproduce the z=0 universe. We show that the same model is capable of reproducing the current UV luminosity function constraints even up to z=17 without the need to invoke variations in the baryon physics model. This model is also capable of reproducing reasonably well the stellar mass function evolution from z=0 to z=10 and the cosmic star formation rate (SFR) density at 0<z<15, again with the same baryon physics and parameters. The key to the success of Shark is the triggering of starbursts by violent disk instabilities included in the model, which leads to an increase in the variance of the UV luminosity with increasing halo mass at z>10. We demonstrate that without this mechanism, galaxies are not bursty enough in the model to reproduce the observations at z>10.
Read the full abstract

All authors Claudia D.P. Lagos, Angel Chandro-Gomez, Chris Power, Aaron S.G. Robotham

Mathematical Physics

Controllability, returning waves and scattering without reverberation in 3D acoustic dynamic system

Mikhail I. Belishev and Aleksei F. Vakulenko

The dynamic acoustic scattering system is governed by the wave equation $u_{tt}-\Delta u+qu=0$ in $\Bbb R^3,\,\,\,-\infty<t<\infty$, with a compactly supported potential $q$ and infinitely distant sources (controls) $f$, which initiate incoming spherical waves $u=u^f(x,t)$ provided $u^f\big|_{|x|<-t,\,\,\,t<0}=0$. These waves are focused at $x=0$ and fill up the whole space at the moment $t=0$. The system is controllable if the set of waves $u^f(\cdot,0)$ produced by all finite energy controls $f$, covers the space $L_2(\Bbb R^3)$. As we show, if the Hamiltonian $H=-\Delta+q$ has the bound states, then in the space the points $a$ appear such that the system, being refocused at $x=a$, loses controllability. The latter leads to a physical effect: the waves $u^f$ of finite energy appear, which vanish simultaneously in the past and future cones $|x|<\pm\, t$ and leave the region of inhomogeneity of $q$ without reverberation. This effect has some similarities with the wavefront reversal (Time Reversing Mirror), but is more meaningful from a mathematical point of view.
Read the full abstract

Mathematical Physics · Cross-listed from math.PR

Airy limit for the Jack process and topological expansion

Jiaming Xu

For every $\beta>0$, we establish multi-time soft-edge moment convergence for a class of Jack processes, including the Jack–Plancherel process, a discrete $\beta$-analogue of Dyson Brownian motion. The limiting moments admit an absolutely convergent expansion in terms of nonnegative Brownian bridges decorated by pairs of equal and opposite jumps. At equal times, we identify this limit with the joint Laplace statistics of the Airy$_\beta$ process for $\beta\geq1$. The same Brownian expansion yields an asymptotic $\beta$-topological expansion of the marginal $b$-conjecture and, at $\beta=2$, an explicit nonnegative formula for the Witten–Kontsevich intersection numbers.
Read the full abstract

High Energy Physics (Theory)

Topics in Kadyshevsky Field Theory

Th.A. Rijken and J.W. Wagenarr

In these notes we deal with several field theoretical topics in the framework of the Quantum Field Theory as developed by Kadyshevsky. The main motivation for studying the Kadyshevsky formalism is that in the kadyshevsky graphs, in contrast with the Feynman graphs, the particles remain on the mass shell. This facilitates the use of phenomenological form factors, e.g. Gaussian ones. In the first part we construct the second quantised quasi-particle formalism, which is employed to develop the functional integral formalism. In the latter we develop the path-integral, the Schwinger-Symanzik equations, generalised Wightman functions, and the Kadyshevsky reduction formulas. In the second part we cover the topics: (i) the relation between the Feynman and Kadyshevsky perturbation theory, and (ii) the Gross-Jackiw method in the Kadyshevsky formalism. The latter method is applied to the kadyshevsky formalism for interaction Lagrangians with derivatives, in particular for pion-nucleon interactions: (i) pseudo-vector $NN\pi$-, (ii) vector $NN\rho$-, and (iii) gauge-invariant $\Delta_{33}N\pi$ coupling.
Read the full abstract

High Energy Physics (Theory)

Center-twisted Gribov spectra and the finite-volume Gaussian response in the refined Gribov–Zwanziger framework

Okuto Morikawa

We develop a continuum framework for comparing the Gribov–Zwanziger and center-vortex descriptions of confinement through the gauge-invariant twisted partition function of the electric $\mathbb{Z}_N^{[1]}$ 1-form symmetry. A background 2-form field $B$, equivalently an 't~Hooft twist on a torus, labels a global sector and is not itself a dynamical center vortex. For a minimal irreducible twist on $T^4$, we derive the complete adjoint momentum lattice of $SU(N)$. The twisted spectrum is exactly the scalar spectrum on an enlarged torus with periods $(L_1,L_2,NL_3,NL_4)$ with the ordinary-torus sublattice removed. This yields a finite Faddeev–Popov gap at the flat representative and reduces twisted-minus-untwisted spectral traces to ordinary torus traces. For the refined Gribov–Zwanziger (RGZ) kernel, Poisson resummation gives an exact finite-volume Bessel-function winding sum with a universal center-twist projector. We evaluate the Gaussian one-loop integral at fixed RGZ parameters up to the finite-dimensional global zero-mode/stabilizer normalization. The Zwanziger determinants cancel, while the gauge-fixing/ghost sector leaves a universal massless primed determinant on $T^4$; the untwisted sector also contains constant gluon modes. The only normalization not fixed by the local quadratic Hessian is the relative zero-mode/stabilizer measure of the reducible untwisted and irreducibly twisted flat connections. We also derive closed finite-volume sources for the RGZ stationary equations. The massive response is exponentially suppressed at large volume, whereas the massless factor depends on the global zero-mode normalization. Thus the Gaussian calculation does not by itself establish the strong center-vortex-condensation criterion for $Z[B]/Z[0]$, but it isolates the remaining global normalization problem and separates a global twist from an actual dynamical vortex.
Read the full abstract

Strongly Correlated Electrons

Non-Resonant Impulsively Stimulated Raman Scattering by a Terahertz Field: a Case Study of 1T-TaS2

Haotian Zhang, Yuheng Guo, Zidu Yu et al. (+7 more)

Time-domain ultrafast and nonlinear terahertz spectroscopy techniques are recently applied to many condensed matter systems for investigating their collective excitations. In centrosymmetric systems, these collective modes are typically Raman-active and therefore do not couple directly to the terahertz electric field. The mechanism by which light-matter interaction realizes in these studies has not been explicitly discussed in detail. In this work, we perform terahertz pump - optical probe and terahertz third harmonic generation investigations on 1T-TaS2, a material exhibiting a rich charge-density-wave (CDW) phase diagram including the commensurate, nearly-commensurate and incommensurate CDW phases. The transition between these distinct states leaves a clear signature on the dynamical Raman response. We investigate how the Raman-active phonons couple to a broadband monocycle terahertz field as well as a narrowband multicycle terahertz field. Our results indicate that a modified impulsively stimulated Raman scattering mechanism involving two-photon absorption, also known as non-resonant Raman scattering, underlies the coherent excitation and observation of the lattice modes. These results are relevant for future spectroscopy investigation and coherent control of collective modes using low-energy terahertz field as well as cavity electrodynamical dressing of solids.
Read the full abstract

All authors Haotian Zhang, Yuheng Guo, Zidu Yu, Yongbo Lv, Yiting Wang, Liwen Feng, Jiaying Xu, Tianlong Xia, Xinbo Wang, Hao Chu

Materials Science

Orbital-Free DFT-Assisted Machine-Learned Molecular Dynamics for Electric-Field-Driven Ionic Transport

Yusuke Nishiya, Hiroya Nakata, Yosuke Harada et al. (+1 more)

We propose an orbital-free density functional theory (OFDFT)-assisted machine-learned molecular dynamics method in which field-independent interatomic forces are evaluated using a machine-learned potential and atomic charges that depend on the local environment are obtained from OFDFT calculations. The atomic charges obtained by Bader partitioning of the OFDFT electron density are multiplied by the electric-field vector and added to the forces from the machine-learned potential. This approach enables molecular dynamics simulations under an electric field at a lower computational cost than Kohn-Sham DFT (KSDFT)-based molecular dynamics. As a proof of concept, the method was applied to beta-Li3PS4 bulk and an S8/Li3PS4 heterostructure under periodic boundary conditions. For Li3PS4 bulk, OFDFT yielded Li charges and a total charge of the PS4 unit consistent with those obtained using KSDFT. In the heterostructure, Li ions migrated from the Li3PS4 region into the S-rich region within a simulation time of approximately 170 ps. Accompanying this migration, the mean Bader charge of the S atoms that initially formed S8 rings changed from nearly neutral to negative. A comparison with KSDFT for a representative interfacial structure also confirmed that the negative charging of the S atoms upon the arrival of Li and the magnitude of the Li charges were qualitatively reproduced. These results demonstrate the possibility of treating field-driven ionic transport and changes in interfacial charge states using a universal machine-learned potential without training an additional material-specific charge-prediction model.
Read the full abstract

All authors Yusuke Nishiya, Hiroya Nakata, Yosuke Harada, Yu-ichiro Matsushita