Nuclear Theory
Physics-informed interpretable forms for dipole resonances and quantities relevant for astrophysics
Gourab Banerjee, Jhilam Sadhukhan, Debasish Mondal et al. (+3 more)
We have employed
Bayesian inference to extract the centroid energies and widths from the isovector giant dipole resonance (IVGDR) data for the IVGDR built on the ground states of
nuclei.These IVGDR properties were modeled by explicitly incorporating the structural effects like isospin asymmetry, nuclear deformation and shell correction. The resulting parametrizations reproduce the IVGDR systematics with remarkable precision for both spherical and axially deformed
nuclei. Subsequently, the extracted IVGDR parameters were used to constrain the coefficients of the nuclear
symmetry energy, which are found to be in good agreement with recent measurements of nuclear dipole polarizability. Furthermore, these
symmetry-energy coefficients were employed to predict the dipole polarizability within different self-consistent mean-field models and to investigate its correlation with the
neutron-skin thickness. The present findings provide valuable input for large-scale calculations of radiative capture processes relevant to nuclear astrophysics and for improving our understanding of astrophysical scenarios under extreme conditions.
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All authors Gourab Banerjee, Jhilam Sadhukhan, Debasish Mondal, B. K. Agrawal, Chandrani Sen, S. Mukhopadhyay
Quantum Physics
Spin-outcome correlations and memory-assisted entropic uncertainty in Bhabha scattering with an entangled spectator
Zan Cao, Meng-Long Song, Xue-Ke Song et al. (+2 more)
We investigate
spin-outcome correlations and
memory-assisted entropic uncertainty in tree-level Bhabha scattering, where an incident electron $A$ scatters with a positron $B$ initially entangled with a spectator electron $C$. For the fixed-angle post-selected final state, we compare the total
memory-assisted uncertainty $U_A$ for three alternative Pauli measurements on $A$ with the
entanglement entropy $S(\rho_A)$ across the $A|BC$ partition. We resolve $U_A$ into the separate uncertainties $U_B$ and $U_C$ and evaluate the corresponding outcome-
memory mutual-information sums $G_B$ and $G_C$. This separates changes in the randomness of the outcomes on $A$ from changes in their correlations with each
memory. In the parameter regions studied, enhanced $A|BC$
entanglement is accompanied by lower $U_A$, most prominently near high-energy backscattering. An analytic treatment of this limit shows that $B$ factorizes from $AC$: $G_B$ vanishes, whereas $G_C$ increases with the initial $B$-$C$
entanglement. An entropic complete complementarity analysis characterizes the accompanying loss of local helicity predictability in $\rho_A$ and changes in the coherence, predictability, and mixedness of the interacting pair $\rho_{AB}$. These results show that initial $B$-$C$
entanglement can lower the total
memory-assisted uncertainty in high-energy backscattering by strengthening
spin-outcome correlations with the spectator $C$, thereby identifying the distinct roles of the interacting particle and the spectator as
quantum memories.
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All authors Zan Cao, Meng-Long Song, Xue-Ke Song, Liu Ye, Dong Wang
General Relativity and Quantum Cosmology
FLRW-Compatible Tensors and Perfect-Fluid Universality in Modified Gravity
Cem Dalk{\i}rmaz and Yaghoub Heydarzade
We study FLRW-compatible tensor fields on Friedmann–Lemaître–Robertson–Walker spacetimes in $(D+1)$ dimensions equipped with Levi-Civita connection. We prove that any covariant rank-$N$ tensor field invariant under the spatial homogeneity and isotropy group, with $D>N$, admits a finite decomposition into monomials constructed from the metric tensor $g_{\mu\nu}$ and the unit timelike vector $u_\mu$, with scalar coefficients depending only on
cosmic time. As a direct consequence, any rank-two correction term appearing in an Einstein-like rearrangement of the FLRW background field equations has the effective perfect-fluid form for $D>2$. Thus, the result provides an arbitrary-rank tensorial classification underlying the perfect-fluid structure of modified
gravity equations on FLRW backgrounds, complementing existing rank-two universality results. Applications to generalized Friedmann equations and to the geodesic deviation equation in modified
gravity are also discussed.
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High Energy Physics (Theory)
No Particle Production and Integrability in AdS$_2$
De-liang Zhong and Xinan Zhou
We propose an analogue of the no particle production condition in two-dimensional anti-de Sitter space, and demonstrate how this criterion uniquely reconstructs the curved-space Liouville and Toda theories via general-multiplicity holographic correlators.
General Relativity and Quantum Cosmology
Holographic dark energy from generalized entropies and extended infrared cut-offs
Ke Chen, Simone D'Onofrio, Sergei D. Odintsov et al. (+1 more)
We study holographic dark energy models constructed from generalized
entropy functionals and local infrared cut-offs. Three
entropies (Barrow and the three and five-parameter generalized
entropies) are each combined with the Granda-Oliveros (GO) cut-off and two extensions, one adding a $\gamma H^{-2}$ term and one a $\gamma \ddot{H}/H$ term, the latter raising the dark-energy
evolution equation to second order. The nine resulting models are constrained against DESI DR2 BAO, Pantheon+ and a Planck compressed CMB likelihood through an MCMC analysis, and compared using the Akaike and
Bayesian information criteria. The Hubble constant is stable across all models. The $H^{-2}$ term is unconstrained in every case, as it becomes relevant only in the far future, and never improves on the GO cut-off. The $\ddot{H}/H$ term, instead, is tightly constrained for Barrow and $S_5$, where it improves the fit substantially, but not for $S_3$. The best fit is obtained for Barrow
entropy with the $\ddot{H}/H$ cut-off, yet the Barrow exponent remains compatible with zero in all cases. The data thus favour a higher-order infrared cut-off, while showing no significant evidence for a departure from the Bekenstein-Hawking area law. We also investigate the dark energy equation of state (EoS) of $S_3$ and $S_5$, discovering quintessence-like behavior and phantom crossing.
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All authors Ke Chen, Simone D'Onofrio, Sergei D. Odintsov, Tanmoy Paul
Mathematical Physics
Extended States on the Bethe Lattice Revisited
Vojkan Jaksic and Yoram Last
We give a short proof of the classical weak-disorder result that the Anderson model on the Bethe
lattice has purely absolutely continuous spectrum on compact intervals in the interior of the free spectrum. This note continues [6], where we gave a minimal proof of the existence of a nontrivial absolutely continuous component using the cyclicity criterion of [8]. There, Hellinger overlap yields the required non-cyclicity. Here, a stability argument for the forward Green function, followed by the zero–one law for the tree recursion, yields positivity of its boundary imaginary part. This positivity already gives absolutely continuous spectrum throughout the interval; the structural result of [7] excludes singular spectrum and yields purity. We also observe that the same structural argument shortens the final passage from boundary positivity to purity in the recent OpenAI preprint on the weak-disorder Anderson model on $\zz^d$, $d\geq3$ [10].
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Quantum Physics
Remote nonreciprocal magnon magnon entanglement via the Barnett effect with coherent feedback
Jinhao Jia, Yingyu Li, Ran Liang et al. (+3 more)
We propose a scheme for generating and controlling remote nonreciprocal
magnon–
magnon entanglement in a cavity magnonic system with coherent feedback.The two microwave cavities are driven by independent single-mode squeezed
vacuum fields, with a rotating YIG sphere in the left cavity and a stationary one in the right cavity. For a fixed rotation direction, reversing the bias
magnetic field applied to the rotating sphere changes the sign of the Barnett shift, leading to nonreciprocal
magnon–
magnon entanglement. By tuning the cavity detuning and feedback phase,
entanglement can be generated for one direction of the bias
magnetic field while it vanishes for the opposite direction, yielding complete nonreciprocity. Coherent feedback enhances the
entanglement at an appropriate reflectivity, whereas stronger feedback can reduce it. The relative squeezing phase provides additional control, and an appropriate choice of unequal squeezing factors improves the
entanglement at fixed total input
photon occupation. With the squeezed inputs kept fixed, moderate feedback also increases the critical temperature for
magnon entanglement.Our results provide a controllable approach to preparing remote nonreciprocal
quantum correlations in cavity magnonic systems.
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All authors Jinhao Jia, Yingyu Li, Ran Liang, Qinghua Cai, Xin Wen, Mei Zhang
High Energy Astrophysical Phenomena
Radio Continuum Study of One of the Brightest Large Magellanic Cloud Supernova Remnants N 132D
Rami Z. E. Alsaberi, Zachary J. Smeaton, Miroslav D. Filipovic et al. (+5 more)
We present a new
radio continuum study of the Large Magellanic Cloud
supernova remnant N 132D using observations from the Australia
Telescope Compact Array (ATCA) and MeerKAT. The
radio morphology shows a clear spatial correlation with the X-ray emission in the central and left regions of the remnant, as well as in the right portion of the shell, indicating a close connection between the thermal and non-thermal
plasma components. Polarisation measurements reveal predominantly radial
magnetic fields, with mean fractional polarisations of 1.2 per cent, 3.0 per cent, and 4.0 per cent at 2100, 5500, and 9000 MHz, respectively. There is also a complex structure in the Faraday Depth spectrum, showing a double-peaked profile that indicates regions with differing magnetisation properties or varying
magnetic field geometry. The rotation measure derived from ATCA data has an average value of ~2 rad m^-2, with a maximum of ~338 rad m^-2. We estimate a constant partition
magnetic field of ~90 microG and a minimum energy of 3 x 10^50 erg, which is in a constant partition between the energy density of electrons and the energy density of the
magnetic field. The integrated
radio spectrum follows a power law with a spectral index of -0.74 +- 0.01. These results provide new constraints on the
magnetic field structure and energetic properties of N 132D and offer insight into particle acceleration and shock
evolution in young
supernova remnants.
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All authors Rami Z. E. Alsaberi, Zachary J. Smeaton, Miroslav D. Filipovic, Roland Kothes, Hidetoshi Sano, Ahmed H. Abdullah, Dejan Urosevic, Sanja Lazarevic
Plasma Physics
Imaging ablator-fuel mix of hot spot in inertial confinement fusion via resonant X-ray absorption using an X-ray free electron laser
Lingen Huang, Long Yang, Alejandro Laso Garcia et al. (+44 more)
A novel diagnostic is proposed for active probing of doped inertial confinement fusion (ICF) spherical shells, enabling direct measurements of mix and burn dynamics at next-generation implosion facilities via resonant absorption imaging with an X-ray free-electron
laser (XFEL). The charge-state-sensitive imaging of embedded dopants provides spatiotemporally resolved constraints on ionization, opacity, and material mix seeded by hydrodynamic instabilities in stagnated
plasmas. Proof-of-principle experiments demonstrating resonant XFEL probing of hot spot in coated copper wires driven by an ultra-short relativistic
laser pulse, have established the feasibility of this approach. Furthermore, atomic and radiation-hydrodynamic simulations, combined with synthetic resonant X-ray absorption imaging, extend the diagnostic concept to
laser-driven direct-drive ICF shells with copper-doped ablators and radiation-driven indirect-drive shells with tungsten-doped ablators. This unique approach, combining a
laser-driven implosion facility with a high-brightness XFEL, could enable precise measurements of fusion-relevant hot dense
plasmas at multi-keV temperatures, provide stringent
benchmarks for radiation-hydrodynamics models, and advance the realization of inertial fusion energy.
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All authors Lingen Huang, Long Yang, Alejandro Laso Garcia, Oliver S. Humphries, Michal Šmíd, Mikhail Mishchenko, Victorien Bouffetier, Carsten Baehtz, Erik Brambrink, Samuele D. Di Dio Cafiso, Gabriel Pérez-Callejo, Yangzhe Cui, Thea Engler, Wen Feng, Sebastian Göde, Joerg Grenzer, Christian Gutt, Johannes Hagemann, Marie-Luise Herbert, Arthur Hirsch-Passicos, Hauke Höppner, Thomas Kluge, Dominik Kraus, Julian Lütgert, Masruri Masruri, Motoaki Nakatsutsumi, Özgül Öztürk, Paweł Ordyna, Xiayun Pan, Franziska Paschke-Bruehl, Alexander Pelka, Thomas R. Preston, Chongbing Qu, S.V. Rahul, Lisa Randolph, Martin Rehwald, Hans-Peter Schlenvoigt, Samuel Schumacher, Ulrich Schramm, Jan-Patrick Schwinkendorf, Georgiy Shoulga, Monika Toncian, Jan Vorberger, Karl Zeil, Ulf Zastrau, Toma Toncian, Thomas E. Cowan
Astrophysics of Galaxies
Measuring radial flows in disc galaxies
Yi He, Filippo Fraternali, Pavel E. Mancera Piña et al. (+1 more)
Numerous theoretical studies suggest that gas
accretion from the intergalactic medium is essential to feed
star formation in
galaxies throughout
cosmic time. However, the mechanism of gas
accretion remains poorly understood, as direct evidence is lacking. In some models, gas
accretion is expected to take place in the outer discs of
galaxies, from where it should be transferred to the inner
star-forming discs through radial flows. Finding such flows and quantifying them, therefore, opens the possibility of inferring the detailed properties of the accreting gas. Unfortunately, detecting radial flows is challenging due to the large disparity between radial and rotational velocities. Additionally, the distortions in velocity fields produced by these flows resemble the effects of warped structures, further complicating their quantification. To address this, we have developed a new methodology to measure axisymmetric radial velocities in disc
galaxies. Relying on the 3D kinematic fitting software \texttt{$^{\rm 3D}$Barolo}, we have designed a dedicated workflow to measure axisymmetric radial motions in disc
galaxies and to obtain robust uncertainty estimates through a bootstrapping approach. We validated this approach using realistic axisymmetric mock
galaxies as well as a small sample of `observed' Milky Way-like
galaxies drawn from the TNG50 hydrodynamic simulation. These tests demonstrate that our method works well and is capable of overcoming the degeneracy between radial motions and warps. The TNG50
galaxies we analysed have large regions in their discs with non-axisymmetric inflows and outflows, but they show, on average, no global trend of coherent radial flows.
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All authors Yi He, Filippo Fraternali, Pavel E. Mancera Piña, Enrico M. Di Teodoro
Materials Science
Achieving room temperature plasticity in TiO2 ceramics by flash processing
Xinghua Su, Zhenyu Li, Xufei Fang et al. (+3 more)
Ceramics are indispensable materials for modern engineering and high-technology applications. However, the intrinsic brittleness at room temperature can cause catastrophic failure and severely limit their widespread applications. Here, we report a flash processing (FP) method based on the coupling of electric and thermal fields to significantly improve the room-temperature plasticity of TiO2 ceramics with a large plastic compressive strain of 15.4% during micropillar compression. This large room-temperature plasticity is attributed to the proliferation of stacking faults and twin boundaries during the loading process, which may be assisted by the high concentration of oxygen vacancies introduced by the FP method. Our findings suggest that FP can be a simple and effective method for achieving improved room-temperature plasticity of ceramic materials through defect engineering.
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All authors Xinghua Su, Zhenyu Li, Xufei Fang, Wenjun Lu, Mengyao Wang, Peng Zhao
Optics
Undetected Photon Spectroscopy in the Long-wave and Far Infrared
Jinghan Dong, Jingrui Zhang, Haichen Zhou et al. (+3 more)
Spectroscopy with undetected
photons allows the spectral response of a sample at long wavelengths to be measured through interference of a shorter-wavelength signal field, without directly detecting the light that probes the sample. Previous demonstrations of undetected-
photon spectroscopy in the molecular fingerprint region have reached approximately 10.5 microns, leaving longer wavelengths largely unexplored. Here, we extend this approach to 20 microns wavelength, demonstrating infrared undetected-
photon spectroscopy using a BaGa2GeSe6 (BGGSe)-based nonlinear interferometer while only the near-infrared (NIR) signal is detected using a silicon detector. Rotation of the BGGSe
crystal provides broad wavelength tuning, and
Fourier-transform analysis of the signal interferograms yields the corresponding idler spectra and sample transmittance. Broadband absorption spectroscopy is demonstrated using Kapton across a 7.8-20 microns wavelength range, with the measured absorption agreeing with independent infrared measurements. The same system is further employed to detect sulfur hexafluoride (SF6) gas via spectroscopy near 10.55 microns. These results substantially extend the accessible spectral range of spectroscopy with undetected
photons while retaining silicon-based NIR detection.
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All authors Jinghan Dong, Jingrui Zhang, Haichen Zhou, Weijie Nie, John G. Rarity, Alex S. Clark
High Energy Physics (Phenomenology)
Selected open-charm decays of the narrow \(P_c\) states: Quark-interchange predictions and pion-exchange sensitivity
Vandan Patel and Ajay Kumar Rai
The proximity of the narrow $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ structures to the $\Sigma_c\bar D^{(*)}$ thresholds motivates their interpretation as hadronic molecules. We treat the $P_c(4312)$ as an $S$-wave $\Sigma_c\bar D$ state with $J^P=1/2^-$ and examine both $J^P=1/2^-$ and $3/2^-$ $\Sigma_c\bar D^*$ assignments for each heavier peak. The selected $S$-wave open-charm transitions to $\Lambda_c\bar D^{(*)}$ are calculated at Born order in the
quark-interchange model, including the prior and post rearrangement diagrams and their color, flavor,
spin, and spatial
matrix elements. Across the input variations considered, the
quark-interchange widths robustly favor $\Lambda_c\bar D^*$ over $\Lambda_c\bar D$ for every $J^P=1/2^-$ assignment. At either heavier peak mass, the $\Lambda_c\bar D^*$ width for $J^P=3/2^-$ is suppressed by approximately one order of magnitude relative to $J^P=1/2^-$, providing a potential decay-based discriminator of the
spin assignments. The large channel hierarchies arise from spatial overlaps and interference between
spin-independent and hyperfine contributions and are not universal heavy-
quark-
spin-
symmetry ratios. We also explore a retarded one-pion-exchange transition at first Born order. It affects $P_c(4312)\to\Lambda_c\bar D^*$ most strongly, while the coherent widths remain sensitive to the cutoff, energy-transfer prescription, short-distance subtraction, and unresolved relative matching sign. The
quark-interchange hierarchies are therefore the central predictions, whereas the pion-exchange results quantify matching sensitivity. Measurements of the $\Lambda_c\bar D^*$ modes can directly test these patterns.
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High Energy Physics (Theory) · Cross-listed from math.AG
Injectivity of specialization maps in critical cohomology
Yalong Cao
Specialization maps are natural maps from equivariant vanishing cycle cohomology to the equivariant cohomology of the ambient space. We study their injectivity problem for moduli stacks of representations of quivers with potentials, including those associated with generalized conifolds and finite subgroups of $SO(3,\mathbb{C})$. Applications to the irreducibility of modules of Reshetikhin type shifted Yangians are also given.
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Strongly Correlated Electrons
Multipolar fluctuations in localized $4f^2$-electron systems from dynamical mean-field theory: application to $\mathrm{PrCdNi}_4$
Koki Numa and Junya Otsuki
Multipolar-fluctuation analysis based on density functional theory combined with dynamical mean-field theory is extended from $4f^1$- to $4f^2$-electron systems. Two methodological developments are presented. First, many-particle states are constructed within the $j$-$j$ coupling scheme in the $j=5/2$ subspace, so as to reproduce the crystalline-electric-field splitting of the $4f^2$ Hund's-rule ground-state multiplet. Second, multipolar susceptibilities and interactions between $4f^2$ multiplets are derived through a mapping from single-particle to many-particle bases. We apply this framework to PrCdNi$_4$, which has a non-Kramers $\Gamma_3$ doublet ground state, and propose a $(3z^2-r^2)$-type antiferroquadrupolar order at $\boldsymbol{q}=(2\pi,\pi,0)$ driven by the competition between nearest- and fourth-nearest-neighbor interactions. The formalism developed here is applicable to general $4f^n$-electron systems.
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Physics and Society
Breaking Behavioral Uniformity in Traffic Flow: Analytical Derivation and Numerical Verification of Optimal Cooperative Buffering
Raphael Korbmacher and Antoine Tordeux
Stop-and-go waves pose a persistent challenge in traffic flow theory, significantly compromising highway safety, operational efficiency, and environmental sustainability. This paper mathematically derives an optimal cooperative driving policy based on the premise that connected vehicles can cooperate and assume distinct roles. In doing so, we depart from the classical assumption of uniform vehicular behavior. Through a rigorous optimization formulation constrained by linear stability conditions, it is analytically proved that the traffic system's throughput is globally maximized when a single designated "buffer" vehicle maintains an enlarged headway to absorb perturbations, enabling the remaining vehicles to form a tightly spaced, high-capacity platoon. This analytically derived optimum is confirmed via numerical spectral analysis and stability-constrained flow optimization using the Intelligent Driver Model and the Full Velocity Difference Model. The results demonstrate that this non-uniform cooperative buffering strategy yields dual benefits. It radically expands the string-stable parameter space to actively dissipate SGWs, while simultaneously achieving significantly higher traffic flow compared to both unbuffered traffic and non-cooperative Jam-Absorption Driving strategies.
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Materials Science
Demonstration of ultrafast coherent sub-picosecond magnon pulses
Peter Kubaščík, Miina Leiviskä, Martin Bušina et al. (+20 more)
Ultrafast magnonics explores routes towards energy-efficient information processing by replacing electrons with pulses of terahertz
magnons. The critical, but so far elusive, requirement on the
magnon pulses is the combination of high-speed and a long-range propagation while maintaining a well-defined narrow waveform of the pulses. Here, we demonstrate the launching of 0.4-picosecond
magnon pulses in the altermagnetic
insulator $\alpha$-Fe$_2$O$_3$ (hematite) using broadband terahertz
spin-orbit torques by an adjacent platinum layer. Phase-resolved terahertz transmission reveals that these sub-picosecond pulses travel ballistically, coherently and non-dispersively at a constant velocity of 23 nm/ps, transport angular momentum and retain their temporal waveform shape over 160 nm, with an inferred relaxation length in hundreds of nanometers or more. Beyond establishing $\alpha$-Fe$_2$O$_3$ as an optimal platform for ultrafast magnonics, our technique introduces a high-resolution, tabletop method to directly extract dispersion relations up to high wavevectors, and explore ultrafast
magnon dynamics in altermagnets and other
magnetic materials with teraherz-range dynamics.
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All authors Peter Kubaščík, Miina Leiviskä, Martin Bušina, Zdenek Kašpar, Katharina Müller, Jonathan Mak, Monika Scheufele, Gal Lemut, Jose Solano, Oliver Franke, Rostislav Matuška, Jiří Jechumtál, Eva Schmorranzerová, Petr Němec, Petr Kužel, Tobias Kampfrath, Piet W. Brouwer, Matthias Opel, Stephan Geprägs, Matthias Althammer, Tomáš Jungwirth, Helena Reichlova, Lukáš Nádvorník
Astrophysics of Galaxies
Isotopic ratios as probes of star formation and the origin of molecular gas in the Central Molecular Zone
Laura Colzi
The Central Molecular Zone (CMZ) contains most of the dense molecular gas in the Milky Way but forms
stars at a surprisingly low rate. Isotopic ratios provide a unique tool to investigate both the local physical conditions and the nucleosynthetic history of this gas. I summarize recent isotopic studies toward the molecular cloud G$+$0.693$-$0.027. Deuterium fractionation (D/H ratios) reveals a cold ($T_{\rm kin}\lesssim30$ K), relatively quiescent gas component embedded within the otherwise warm and turbulent CMZ, indicating that the earliest stages of
star formation can survive in this extreme environment. I also present new $^{12}$C/$^{13}$C measurements from HC$_3$N and HC$_5$N, including the first constraints from doubly substituted $^{13}$C isotopologues. After accounting for isotopic fractionation with astrochemical models, the inferred elemental ratio ($\sim37$–48) exceeds the canonical CMZ assumed value ($\sim$20), supporting a scenario in which the Galactic center is replenished by less chemically processed gas flowing inward along the Galactic bar.
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Quantum Physics
Quickly extracting fidelity decay rates in random circuit benchmarking experiments
Ake Köhne, Stavros Efthymiou, Joanna Majsak et al. (+6 more)
Randomized benchmarking (RB) with structured
circuits is experimentally scalable, but gives biased short-depth fidelity estimates because incomplete ensemble mixing introduces transient modes. Waiting for these transients to decay in deeper
circuits can push the signal below the noise floor. This is a well-established obstacle, e.g. in linear cross-
entropy benchmarking (LinXEB). Here we overcome this obstacle solely through classical post-processing. We introduce a one-parameter family of
estimators that interpolate between the standard LinXEB-type post-processing and a new post-processing technique we call the trace filter function. Under practical assumptions, the trace filter function provably suppresses transient modes, exposing an interpretable fidelity decay at short depth, with theoretical guarantees comparable to standard RB, at the cost of an increased variance. We bound the variance, analyze the evaluation complexity of the new
estimators, and develop practical post-processing
algorithms. Experiments on a Rigetti superconducting processor validate the method for one-dimensional
circuits of up to 12
qubits: where the standard
estimator requires depth beyond a 40-layer experimental window, the trace filter function yields consistent estimates below 10 layers. Trace-filtered randomized benchmarking therefore extends reliable fidelity characterization to relevant structured
circuit ensembles and short-depth regimes that are inaccessible to conventional
estimators.
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All authors Ake Köhne, Stavros Efthymiou, Joanna Majsak, Jadwiga Wilkens, Bram Evert, Andrew D. Patterson, Jonas Helsen, Markus Heinrich, Ingo Roth
Quantum Physics
An Efficient Quantum Circuit for Flow Model Execution Using Quantum Neural Networks
Rui Che and Ludvig af Klinteberg
Flow models generate trajectories from an initial distribution to a target distribution by solving an ordinary differential equation defined by a velocity field. Flow matching learns this velocity field by modeling the transport dynamics between the two distributions. Wavefunction flow establishes a formal connection between flow models and
quantum dynamics by introducing a continuity
Hamiltonian, which drives the Schrödinger
evolution of
quantum states. In this paper, we investigate accurate and efficient
quantum simulation of the wavefunction flow, thereby realizing the efficient implementation of flow models on
quantum computers. We first leverage a
quantum read-only
memory (QROM)-based phase kickback framework for the wavefunction flow simulation, generating probability densities that closely match those produced by the corresponding conventional flow model. To address the high
circuit-resource cost, we further incorporate a trained
quantum neural network (QNN) into the phase kickback framework, replacing QROM for data encoding. Numerical experiments demonstrate that our proposed method implements flow models on
quantum computers more efficiently, since it maintains the accuracy of wavefunction flow simulation compared with the QROM-based framework, and significantly reduces the
circuit resources.
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Quantum Gases
Nonlinearity management of matter-wave vector solitons of Bose-Einstein condensates in two dimensions
F. Kh. Abdullaev, J. S. Yuldashev and M. Ögren
The
evolution of matter-wave vector
solitons in two dimensions under nonlinearity management is studied. The averaged over strong and rapid modulations in time of the inter-species interactions vector Gross-Pitaevskii equation is derived. The averaging gives the appearance of the effective nonlinear
quantum pressure depending on the population of the other component. Using this system of equations, the dynamical stabilization of the two-dimensional vector matter-wave
solitons under the management of the mean-field nonlinearity is investigated. It is shown that the nonlinear
quantum pressure arrests the collapse in the averaged system, giving rise to stable vector
solitons. Full numerical simulations of the original, time-dependent system of Gross-Pitaevskii equations confirm that the management strongly prolongs the lifetime of these
solitons compared to the unmanaged case.
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Quantum Physics
A Power-Liouville Hermite Orbit: Common Spectral Quantization of the Singular Sextic Oscillator and Fractional-Power Potentials
Artur Ishkhanyan and Miloslav Znojil
A singular sextic oscillator in the finite-Hermite biconfluent-Heun hierarchy generates an exact four-member power-Liouville Hermite orbit. Power coordinate transformations with the Liouville amplitude map the hierarchy member $N=4$ to four half-line Schrödinger spectral charts while preserving the physical regular-recessive Wronskian zero set under energy-coupling reparametrization. Two charts are the previously studied $x^{2/3}$ and inverse-square-root conditionally integrable potentials; the orbit embeds this known power-dual pair together with the singular sextic and linear-plus-quadratic charts. On the selected physical slice, the degree-five accessory compatibility obstruction vanishes identically, while the transformed Frobenius index reproduces both published fractional-power centrifugal coefficients. The common endpoint condition yields an exact discrete sequence of quartic Sturmian eigencouplings for the sextic oscillator. Independent two-sided shooting confirms representative eigencouplings and node counts. A matched large-action analysis further derives the first matched-endpoint correction within the leading Langer action and improves the Maslov-shifted effective-level approximation. The construction thus connects exact Hermite solvability, energy quantization, coupling quantization, and power duality within a single spectral orbit.
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Solar and Stellar Astrophysics
Gaseous SiO and Silicate Clouds in Three Benchmark Early-L Dwarfs
Zhijun Tu, Shu Wang, Xiaodian Chen et al. (+2 more)
Tracing silicon from gaseous SiO into silicate condensates provides a direct view of the condensation process that forms silicate clouds in L-dwarf atmospheres. Here we present evidence for gaseous SiO in three
benchmark early-L dwarfs, HD 89744B, GJ 1048B, and LSPM J0632+5053B, using JWST/NIRSpec and MIRI spectroscopy. Atmospheric
retrievals with and without SiO under multiple cloud prescriptions identify the strongest SiO signatures at 4.0–4.2 and 7.7–8.2 $\mu$m, with the local likelihood diagnostic reaching $4.6\sigma$. In the physical cloud
retrievals, the 8 $\mu$m band probes lower pressures than the 4 $\mu$m overtone, reaching atmospheric layers where
equilibrium SiO is more strongly depleted by silicate condensation. All three objects also show compact Fe opacity at pressures of a few bar. Their inferred gas-phase C/O ratios are consistent with expectations from the host-
star compositions after accounting for refractory oxygen sequestration. Within the adopted Mie treatment of amorphous silicate grains, the silicate mineralogies favor Mg$_2$SiO$_4$ for HD 89744B and a mixed Mg$_2$SiO$_4$+MgSiO$_3$ cloud for GJ 1048B. Extending this framework to cooler L dwarfs will trace the coupled
evolution of gaseous SiO depletion and silicate-cloud formation along the L-dwarf sequence.
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All authors Zhijun Tu, Shu Wang, Xiaodian Chen, Haomiao Huang, Jifeng Liu
Materials Science · Cross-listed from cs.AI
AtomWorld-Mirror: Macro-Step World Modeling of Critical Evolution Backbones for Materials Dynamics
Ziming Pan, Ruge Zhang, Haozhi Han et al. (+7 more)
Atomistic simulation is a fundamental tool for studying long-term materials
evolution, from
diffusion and defect dynamics to interfacial reactions and fracture. Yet conventional simulators typically advance at microscopic resolution, spending substantial computation on low-impact local updates before reaching structurally consequential states, an evolutionary-resolution bottleneck that limits long-horizon simulation. We propose AtomWorld-Mirror, a time-aware macro-step world model for the critical
evolution backbone of atomic systems. For Step-Wise atomistic simulation, AtomWorld-Mirror distills short micro-event segments into physically reachable transitions between key states, jointly predicting sparse structural edits and accumulated physical time through latent macro-step dynamics. Local reachability, inventory conservation, and continuous-time consistency constrain each transition. By amortizing local atomic physics into a reusable latent macro model and replacing explicit micro-event replay with macro-step inference, this formulation provides a path toward substantially faster prediction of long-term materials
evolution while preserving structural validity and time semantics. Across five atomic systems, spanning Cu-rich RPV steel irradiation aging, Cu-Zr metallic glass, and Li$_3$N-based anti-perovskite solid electrolyte, macro-step inference delivers a speed up of $10^3$ to $10^4$ times over event-by-event simulation.
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All authors Ziming Pan, Ruge Zhang, Haozhi Han, Junkai Zhou, Xingyuan Chen, Yifeng Chen, Yunquan Zhang, Ting Cao, Yunxin Liu, Kun Li
General Relativity and Quantum Cosmology
Bulk-boundary decompositions and exact perfect fluid stellar distributions
Sudan Hansraj, Christian G. Boehmer and Ndumiso Buthelezi
The decomposition of the Ricci scalar in terms of bulk and boundary terms gives rise to an interesting gravitational field theory as proposed by Böhmer and Jensko (BJ). BJ went on to suggest functional forms of the bulk contributions in the Lagrangian. For the purposes of astrophysical modelling the boundary terms are non-dynamical and the entire theory is built from the bulk contribution only. The field equations for a stellar perfect fluid distribution are obtained against the background of a conformostatic metric. Since the linear form of the function of the bulk term is equivalent to Einstein we probe the next level of complexity namely the pure quadratic case. The field equations are substantially more complicated than Einstein's equations. The equation of pressure isotropy proves intractable even with simple choices of one of the
geometric potential functions. Accordingly we analyse the case of the potentials varying inversely with the radius. Viable models do not arise in this case and so we postulate a proportional relationship between the potentials. It turns out that a physically reasonable shell of isotropic fluid may be constructed that satisfies elementary physical requirements. Finally we investigate the isothermal fluid where both density and pressure go as the inverse square law of the radius. This results in fluid behaviour that is comparable to that in the corresponding Einstein model.
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Quantum Physics · Cross-listed from cs.CR
Certifying Hidden Paths: Scalable Topology Assurance for QKD Networks
Alessandro Colombo, Margherita Cozzolino, Stephan Krenn et al. (+1 more)
Large-scale
Quantum Key Distribution (QKD) networks rely on trusted repeaters, making the security properties of the selected communication path an essential part of end-to-end assurance. At the same time, network operators may be unwilling to disclose their internal
topology. We present a
topology-certification mechanism that lets a provider prove in zero knowledge that policy-compliant routes between two endpoints exist, without disclosing the routes in an individual presentation. Our main idea is to certify nodes and edges independently using multi-message signatures, rather than signing the complete graph as one object. For a route chosen in advance, proof size and cryptographic proving and verification work depend on its positions and attributes, independently of the overall network size, whereas route discovery and certification have separate graph-dependent costs. The construction hides the actual route length up to a public bound and sketches extensions to node-disjoint routes and monotonic additions within a graph epoch. We give a formal security model and conditional proofs of unforgeability and graph hiding for a generic construction. For a BBS-based construction, presentation-size estimates remain below $300$\,KiB at $\ell=m=n=50$, and measured generation and verification times remain below $400$\,ms at $\ell=64$ and $m=n=8$.
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All authors Alessandro Colombo, Margherita Cozzolino, Stephan Krenn, Thomas Lorünser
Materials Science
Effects of chlorine substitution on the magneto-optical properties of CrSBr
Z. Śnioch, R. Komar, M. Kuna et al. (+7 more)
We present a systematic study of the effects of chlorine substitution on the magneto-optical properties of the van der Waals layered
semiconductor CrSBr. Our study shows that even at substitution level of $x=56\%$ the $\mathrm{CrSBr_{1-x}Cl_{x}}$ material exhibits qualitatively the same clear magneto-optical coupling that was observed in pure CrSBr
crystals. The values of the relevant parameters are shown to vary smoothly across different substitution levels, thus offering promising tunability for this family of 2D
magnetic materials.
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All authors Z. Śnioch, R. Komar, M. Kuna, M. Raczyński, K. Mosina, A. Söll, Z. Sofer, K. Wohlfeld, P. Kossacki, T. Kazimierczuk
Optics
Learning qBIC Resonances across Metasurface Families in Dielectric Fourier Space
Shuangteng Lei, Li Yu, Tianxin Li et al. (+1 more)
Bound states in the continuum (BIC) metasurfaces are typically described by geometry-specific parameters, hindering cross-geometry comparison, while ultranarrow qBIC features are easily diluted in full-spectrum learning. Here, 2015 samples from seven dielectric metasurface families are mapped to a shared reciprocal-
lattice grid, where two frozen low-order
Fourier channels capture resonance shifts with mean within-branch $R^2$ values of 0.871-0.999. Field-level analysis of two representative branches further confirms that these shifts are consistent with the Maxwell-
Fourier perturbation picture. A five-channel K-space backbone models the broadband spectrum, while a local complex K-space expert parameterizes the qBIC resonance through a differentiable Fano layer. The expert reduces resonance-position mean absolute error (MAE) from 3.2 to 0.95 nm and the resonance-depth error by 14-fold on a geometry-blocked test set. The same coordinate supports spectrum-to-structure reconstruction.
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All authors Shuangteng Lei, Li Yu, Tianxin Li, Wei Lu
Atomic Physics
Response of the near-threshold resonances of the $\bm{dt\mu}$ molecular ion to an effective atomic $2s$–$2p$ splitting
Yi Zhang
For the nonrelativistic three-body Coulomb
Hamiltonian, near-threshold resonances of the deuterium–tritium muonic molecular ion ($dt\mu$) are supported by the long-range dipole coupling between degenerate atomic $2s$ and $2p$ states. We study the effect of atomic $2s$–$2p$ splitting on their positions and decay widths. Three-body complex-absorbing-potential calculations resolve additional members of the $L^\pi=0^+$ and $1^-$ series. Their
geometric spacing agrees with that expected from the $1/R^2$ dipole attraction, where $R$ is the atom–
nucleus separation. To assess the effect of splitting, we scan a prescribed $2s$–$2p$ interval using an effective potential in a
spin-independent, nonrelativistic
Hamiltonian. This models the atomic splitting without an explicit Lamb-shift calculation. Within this model, the studied resonances lie closer to the $d\mu(2s)+t$ threshold and have smaller Coulomb decay widths than in the degenerate case. At an effective interval of $0.2\eV$, the seventh $1^-$ member lies within $2\meV$ of this threshold with a full width of about $4\meV$, compared with $48$ and $15.6\meV$ at degeneracy. These values characterize the response within the tested numerical representations. Its width decreases, but its separation from the threshold decreases more strongly. The long-range analysis attributes these shifts and width reductions to modified dipole mixing. It further suggests that atomic $2s$–$2p$ splitting may truncate the infinite accumulation of resonances predicted for degenerate atomic $2s$ and $2p$ levels.
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Quantum Physics
Topological Superradiant Universality Classes in Cavity-Mediated Spin Chains
Yunhao Liu, Sheng Yang, Mingyuan Chen et al. (+1 more)
Superradiant phase transitions are fundamental phenomena in light-matter coupled systems. Here, we uncover a novel class of superradiant criticality that is topologically distinct from previously known superradiant transitions. Using cavity-mediated cluster-Ising chains as an illustrative example, we numerically demonstrate that the critical line separating the superradiant phase from the cavity topological phase hosts robust
symmetry-protected edge degeneracies, a feature absent in conventional superradiant transitions. Remarkably, although its local bulk critical properties are indistinguishable from those of the previously identified topologically trivial superradiant transition, the two criticalities cannot be smoothly connected without breaking the protecting
symmetries or passing through a multicritical point. We further show that such topological superradiant criticality is generic, also occurring in cavity-mediated $\mathbb{Z}_{n}^{}$ cluster-qudit chains, as supported by complementary
lattice simulations.
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All authors Yunhao Liu, Sheng Yang, Mingyuan Chen, Xue-Jia Yu