Nuclear Theory
In-medium hyperon potentials and the quarkyonic hyperon onset: charged $\Sigma$'s in $\beta$-equilibrium and the neutrino connection
Jaroslaw Nowak
Quarkyonic matter resolves the
neutron-
star hyperon puzzle statistically:
neutrons fill low-momentum $d$-
quark phase space, shifting the $S=-1$ threshold from $\muB=M_Y$ to $2M_Y-M_N$ and suppressing residual softening by $1/\Nc^3$ in the Fujimoto–Kojo–McLerran (FKM) mechanism. We dress FKM's IdylliQ model with in-medium potentials, constrained by hypernuclear data and
neutrino-induced hyperon FSI, and find: (i) the dressed onset, $\muB^{\rm onset}=(2M_Y{-}M_N)+2U_Y-\UN$, carries $U_Y$ at weight 2, with $dn_{\rm onset}/dU_Y\simeq0.3\,\nz$ per $10\MeV$, twice the leverage. (ii) A self-consistent
neutron potential enters at weight $-2$, so protection needs $\UN(n_{\rm onset})\lesssim+96\MeV$. (iii) With
leptons in $\beta$
equilibrium, the $\Sigma^-$ ($dds$) onset becomes $\mue\ge258\MeV+\US-\UN$, never reached inside a $2\,\Msun$ core: $\Sigma^-$ switches from first hyperon to forbidden and the $\Sigma$ ordering inverts. (iv) The $\kY\ge\kbu$ continuation gives TOV softening below $0.05\,\Msun$ in the FKM ansatz family and below $0.025\,\Msun$ for the realistic interacting
star, $4$–$8$ below hadronic models. In the family this is a ceiling; generally it is a floor, since hyperons above $\kbu$ are omitted. (v) In an interacting low-density sector calibrated to $\Mmax=2.12\,\Msun$, core strangeness is controlled by $(\UL(\nz),c_\Lambda)$: at $\UL(\nz)=-28\MeV$, the maximum-mass
star is hyperon-free once the supra-saturation $YNN$ turn-over exceeds a few-MeV threshold $c^*_\Lambda$. Projected SBND+DUNE FSI precision pins $\UL(\nz)$ but leaves $c_\Lambda$ – to which
neutrino data are blind – decisive: with the heavy-ion prior, $P({\rm hyperon\mbox{-}free\ core})=0.90$, versus $0.89$ from priors alone, prior-dominated rather than measured. The sharpest observable is differential: $d\Mmax/dU_Y$ is an order of magnitude smaller than in mean-field models, discriminating the two resolutions.
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Disordered Systems and Neural Networks
Transient Reserves, Sink Dampers, and the Failure of Eigenvalue Reasoning in the Attention Propagator
Li Hengyu
The
attention matrix of a causal
transformer is row-
stochastic, iterated over depth, and non-normal by construction. For non-normal operators,
eigenvalues control only asymptotic behavior; finite-depth behavior is controlled by resolvent quantities such as pseudospectra and Kreiss constants. We test, under pre-registered criteria, whether this resolvent view predicts anything about trained
transformers that
eigenvalues miss. Two structural facts organize the analysis: the mask pins the Kreiss constant of every causal
stochastic matrix at $\sqrt{n}$, and deflating the mask-forced Perron projector factorizes the depth deviation dynamics exactly into a product of deflated operators. Across GPT-2, Pythia-410m, and Llama-3-8B, learned non-normality proves to be signed. A routing minority carries excess transient reserve that tracks previous-
token function and doubles when induction heads engage, while the sink majority is suppressed below matched shuffle nulls, so that
attention sinks act as transient dampers. On depth products,
eigenvalue predictions of surviving deviations err by seven to eleven orders of magnitude, an error absent in matched nulls. Checkpoint censuses date this organization to a consolidation phase after
circuit formation, and a clamping intervention on Llama-3-8B establishes a causal chain from three massive activation dimensions through sink
attention to transient damping; LayerNorm models implement the same functions elsewhere. A cross-validated contest concludes that resolvent features are required for depth-transient persistence and routing-head identity, and that no single-operator summary of any kind predicts per-head causal criticality.
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Statistical Mechanics
The scales of disorder in perfect quasicrystals
Alan Rodrigo Mendoza Sosa, Atahualpa S. Kraemer, Michael Schmiedeberg et al. (+1 more)
The classical dichotomy between crystalline order and amorphous disorder is increasingly challenged by novel states that lack conventional crystalline
symmetries while retaining
crystal-like properties. Quasicrystals occupy a distinctive position within this expanding framework by possessing long-range order without translational periodicity, thereby permitting arbitrary $N$-fold rotational
symmetry. Paradoxically, far from their unique
symmetry center, high-
symmetry quasicrystals closely resemble disordered patterns, raising the question of how deterministic order can be detected. Here we show that increasing rotational
symmetry progressively suppresses local statistical signatures of quasiperiodicity, while preserving its underlying exact long-range order. This order is thus concealed below an emergent crossover length that grows linearly with $N$. Therefore, as $N \rightarrow \infty$, the disorder-like regime expands without bound, defining a
symmetry-controlled
geometric critical point at which deterministic order and randomness become statistically indistinguishable over any finite observation window. For finite $N$, however, quasiperiodic order becomes detectable beyond this crossover, revealing a second emergent length scale that we identify as the size of a statistical unit
cell – finite patches over which statistical properties recur despite the absence of conventional translational periodicity. In one dimension, the statistical-unit-
cell size coincides with the crossover length, whereas in two dimensions it grows as $N^2$, remaining smaller than the size of typical approximants and establishing a hierarchy of emergent length scales. Together, the disorder-to-order crossover and statistical unit
cells provide a quantitative framework connecting
crystals, quasicrystals, and amorphous matter, showing how apparent disorder can emerge from purely deterministic geometry.
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All authors Alan Rodrigo Mendoza Sosa, Atahualpa S. Kraemer, Michael Schmiedeberg, Erdal C. Oğuz
Nuclear Theory
Neutrino-induced hyperon final-state interactions as a probe of the in-medium hyperon potential
Jaroslaw A. Nowak
Hyperon single-particle potentials U_Y(rho) govern hyperon propagation in
nuclei and the appearance of hyperons in dense matter, where they soften the
neutron-
star equation of state (EOS) and lower the maximum mass M_max, the hyperon puzzle. Charged-current (anti)
neutrino interactions on argon-40 create Lambda and Sigma hyperons inside the
nucleus. The reconstructed Lambda yield and momentum and a kaon-vetoed final-state-interaction (FSI) Sigma+ tag respond to U_Lambda and U_Sigma at SBND and DUNE energies. We write the potential at low density as U_Y = U_Y(rho_0) (rho/rho_0)^gamma, plus a correction that vanishes at saturation. A detector-level Fisher forecast, with production cross sections, fluxes and efficiencies as nuisance parameters and the
muon kinematics calibrating the production model, determines U_Lambda best at rho* = 0.82 rho_0, independently of gamma. The statistical precision is 1.5 MeV; with the production model profiled and the remaining systematic uncertainties added in quadrature, the total is +-31 MeV, of which the largest item, 18 MeV, is the convention by which the cascade applies the potential. The measurement is a check, with different systematics, of the hypernuclear constraint, +-3.3 MeV at rho*. U_Sigma is not constrained. In relativistic mean-field EOSs anchored to hypernuclear and Sigma-atom depths, M_max for n p Lambda Sigma- matter is 1.94 M_sun for GM1 and 2.03 M_sun for FSU2H with the phi
meson; it depends on a high-density Lambda NN term c_Lambda that the
neutrino data do not constrain. The calculations use the StrangeMC Monte Carlo generator.
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Solar and Stellar Astrophysics
Structure of the Stellar Neighborhood of CQ Tau in the Presence of a Companion in an Elongated Orbit
Tatiana Demidova
There are indirect signs of the presence of a companion near the
star CQ\,Tau. A period of 10\;years was found in the brightness changes. The image of the disk shows an extensive cavity with a size of about 25~AU, surrounded by a
dust ring with a distribution maximum near 53~AU. A simulation of the interaction of
dust and gas in the vicinity of the
star with the CQ\,Tau parameters was carried out, assuming the existence of a companion in an orbit with a period of 10\;years. It was shown that an M-class
star in a highly elongated orbit is capable of forming a region of reduced density around the center of mass of the system, with a size close to the observed one. However, the
dust ring-like structure in this case is located noticeably closer to the
star than observed. Evidence has been obtained that a massive
planet in an outer, relatively binary orbit, could form a ring-shaped
dust structure at a distance similar to that observed.
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Optics
Co-design approach to aperture masking for imaging through atmospheric turbulence
Olivier Herscovici-Schiller, Laurent M. Mugnier, Alice Fontbonne et al. (+5 more)
Aperture masking interferometry is a technique originally designed to alleviate the influence of atmospheric
turbulence on images recorded on ground-based
telescopes. In this communication, we explore the optimization of the aperture mask by an optical/digital co-design approach in order to obtain diffraction-limited images of relatively bright objects imaged through
turbulence. We show that, with a few simplifying assumptions, it is possible to express the Mean Square Error of the restored image as a function of the chosen mask, of the spatial Power Spectral Density of the observed object and of the noise level, without actually computing any image. This allows us to optimize the aperture mask with a reduced computing cost. We also implement a multi-frame myopic
algorithm to estimate jointly the observed object, the piston and the tip-tilt in front of each sub-aperture, and check by simulations that the aperture masks obtained indeed allow a satisfactory image reconstruction.
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All authors Olivier Herscovici-Schiller, Laurent M. Mugnier, Alice Fontbonne, Pauline Trouvé-Peloux, Frédéric Champagnat, Yann Lucas, Yann Lai-Tim, Frédéric Cassaing
Mesoscale and Nanoscale Physics
Terahertz field-driven nonlinear Hall effect and other second order transport phenomena in two-dimensional tellurene
M. D. Moldavskaya, L. E. Golub, E. Mönch et al. (+4 more)
We study terahertz field-driven second-order nonlinear electron transport phenomena, including the nonlinear
Hall effect (NLHE), in two-dimensional tellurene flakes. The dc current excited by linearly polarized terahertz (THz) radiation in
Hall bar samples is investigated in directions both along and perpendicular to the $c$-axis of tellurene. As expected for second-order transport phenomena, the current scales as the square of the in-plane electric field of the radiation $\bf E$, and depends on its orientation. The current results from a combination of three contributions, including the NLHE, the Nonlinear Longitudinal (NLL) and Nonlinear Diagonal (NLD) currents. We established the equivalence between NLH, NLL, and NLD transport currents and Linear photogalvanic effect (LPGE) contributions induced by the absorption of linearly polarized and unpolarized THz radiation. All contributions can be controlled by a gate voltage and have opposite signs for electron and hole conductivity. The magnitude of the current increases drastically when the samples are cooled from room temperature to 4.2 K. It also increases with decreasing radiation frequency. These results are well described by the developed phenomenological and microscopic theories. We show that the THz radiation-induced electric current originates from microscopic mechanisms such as skew scattering, side jump, and the Berry
curvature dipole.
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All authors M. D. Moldavskaya, L. E. Golub, E. Mönch, Chang Niu, Peide D. Ye, J. Wunderlich, S. D. Ganichev
Nuclear Theory
Accelerator neutrinos as a probe of in-medium hyperon potentials
Jaroslaw A. Nowak
Charged-current (anti)
neutrino interactions create Lambda and Sigma hyperons inside the
nucleus, so the hyperons that reach a detector have crossed
nuclear matter and carry the imprint of the in-medium potentials U_Y(rho) that also govern the appearance of hyperons in
neutron stars. In the StrangeMC simulation of argon, the reconstructed Lambda yield and momentum and a kaon-vetoed Sigma+ tag respond to U_Lambda and U_Sigma at SBND and DUNE energies. A detector-level forecast, with the production cross sections, fluxes and efficiencies as nuisance parameters and the
muon kinematics calibrating the production model, determines U_Lambda at rho* = 0.82 rho_0, independently of the low-density exponent of the potential, to 1.5 MeV statistically and +-31 MeV in total. The largest item, 18 MeV, is the convention by which the cascade applies the potential. The measurement is a check, with different systematics, of the hypernuclear constraint, +-3.3 MeV at rho*, for momentum-independent potentials; U_Sigma is not determined. In the relativistic mean-field equations of state GM1 and FSU2H, anchored to the hypernuclear and Sigma-atom depths, the maximum
neutron-
star mass depends on the Lambda NN repulsion, which these data do not constrain.
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Quantum Gases
Observation of a Rydberg-atom time crystal with an ultralong lifetime
Qi-Feng Wang, Tian-Yu Han, Ya-Jun Wang et al. (+9 more)
Continuous time
crystals (CTCs) represent a nonequilibrium
quantum phase that spontaneously breaks time-translation
symmetry without periodic external driving, manifesting as persistent, long-lived oscillations under steady pumping. The lifetime is constrained by the instability of the limit cycle phase, balanced between nonlinear feedback and energy dissipation, which have rarely been studied in experiments before. Here, we report an observation of an ultralong-lived Rydberg-atom CTC in a driven-dissipative many-body atomic system. By harnessing long-range interactions and engineering a dissipative environment that stabilizes the limit-cycle dynamics, we suppress heating and decay effects that typically destroy time-crystalline order. The key factor underlying the ultralong-lived CTC is the closing of the Liouvillian gap and the near-zero real part of the system's Liouvillian eigenspectrum. Through systematic optimization, we achieve an oscillatory lifetime exceeding 16.95 hours-orders of magnitude longer than previous CTC realizations. Our work establishes a robust platform for exploring long-lived autonomous nonequilibrium phases and paves the way for applications in
quantum sensing and continuous-time
quantum information processing.
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All authors Qi-Feng Wang, Tian-Yu Han, Ya-Jun Wang, Dong-Yang Zhu, Chao Yu, Yu Ma, Yi-Ming Yin, Guang-Can Guo, Bang Liu, Li-Hua Zhang, Dong-Sheng Ding, Bao-Sen Shi
Mesoscale and Nanoscale Physics
Screening-controlled dynamical criticality in the quantum Hall regime
Tanima Chanda, Simrandeep Kaur, Anantbir Virk et al. (+5 more)
At continuous electronic phase transitions, Coulomb interactions can modify the relation between length, energy, and temperature, but experimentally disentangling their effects on spatial versus dynamical criticality has remained difficult, since finite-temperature scaling alone measures only the combined exponent $\kappa = 1/(z\gamma)$. Here, we introduce two advances that resolve this limitation. First, by combining temperature scaling with independent current scaling, we separately extract the dynamical exponent $z$ and the localization-length exponent $\gamma$ at the
quantum Hall plateau transition – rather than inferring one from an assumed value of the other. Second, using dual-graphite-gated
graphene devices in which the effective Coulomb interaction range is tuned geometrically by the ratio of the
magnetic length $l_B$ to the graphite-gate distance $d$, we track this separation across both screened and unscreened interaction regimes within the same device platform. Temperature scaling gives $\kappa \simeq 0.21$ in the screened regime and $\kappa \simeq 0.41$ in the unscreened regime; combining this with current scaling reveals that screening changes $z$ from $\simeq 1$ in the unscreened regime to $\simeq 2$ in the screened regime. In contrast, $\gamma$ remains close to $2.4$ throughout. Our results establish that gate-controlled screening selectively modifies the interaction-dependent dynamical sector of the
quantum Hall transition, leaving the localization-length exponent $\gamma$ unchanged within experimental uncertainty. More broadly, this work establishes
geometric screening as a versatile tool for controlling interactions and disentangling interaction and disorder effects in correlated two-dimensional systems, including fractional
quantum Hall states, moiré materials, and other strongly localized electronic phases.
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All authors Tanima Chanda, Simrandeep Kaur, Anantbir Virk, Kenji Watanabe, Takashi Taniguchi, G. J. Sreejith, Yuval Gefen, Aveek Bid
Accelerator Physics
Weak-Strong Steady-State Microbunching Accelerator Light Source
Xiujie Deng, Alexander Wu Chao, Wenhui Huang et al. (+3 more)
We propose a phase space manipulation involving one energy modulation sandwiched by two dispersion sections which converts a bunched particle beam or bunch train to ultra-high-harmonic density modulation, while the energy modulation in principle can be arbitrarily weak. The same scheme can also be used for energy bunching, creating energy levels in a bunched beam. We further propose a mechanism invoking three
laser modulators in a storage ring to longitudinally focus the electron beam both weakly and strongly, such that a microbunch train and its high-density-harmonics or energy bunching form and sustain turn-by-turn. We call this mechanism weak-strong steady-state microbunching (Weak-Strong SSMB). The longitudinal beta function can vary by seven orders of magnitude along such a ring, with the minimal value squeezed to 10 nm. An example application of Weak-Strong SSMB for kW coherent EUV radiation is presented. Extension to X-ray can be anticipated. An energy-leveled electron beam enables $\gamma$-ray frequency comb production. The ideas can be scaled to wavelengths like RF and THz, for bunch length and energy spread control, ultrashort X-ray and coherent THz generation. Our work establishes a new paradigm for longitudinal dynamics study, accelerator light source development, and opens great potential for accelerator physics and technology.
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All authors Xiujie Deng, Alexander Wu Chao, Wenhui Huang, Zhilong Pan, Chuanxiang Tang, Jingyuan Zhao
Quantum Physics
Quantum stochastic thermodynamics of macroscopic systems: an algebraic approach
Antoine Rignon-Bret and Cyril Elouard
We build a framework for the thermodynamics of macroscopic
quantum systems. In contrast with approaches requiring access to the full density
matrix, our framework relies on a coarse-grained description, based on measurement statistics of a few observables. When these observables commute, the outcomes define classical macrostates whose
entropy is quantified by observational
entropy, accounting for uncertainty about both the macrostate and the microstate within it. We extend this notion to non-commuting observables forming a subalgebra of the operator space, and use Jaynes' principle to define an
algebra-dependent
entropy interpolating between von Neumann and observational
entropies. Given initial and final measurement sets, connected by internal and/or environment-induced dynamics, we derive a second law for the coarse-grained dynamics. Unlike formulations based on von Neumann
entropy, our inequality captures irreversibility from both non-
unitary environment-induced dynamics and internal equilibration. It takes the usual form of a positive
entropy production when the system is initially at internal
equilibrium, while correction terms capture nonequilibrium resources ignored by the coarse-graining. We also derive fluctuation
theorems for coarse-grained thermodynamic quantities. Along a quasi-static path of measurement schemes, we identify
quantum macroscopic notions of work and heat fulfilling the first and second laws, including an additional work contribution from manipulating the
algebra to which the system is confined, through external constraints or
quantum measurement backaction. Finally, we apply our framework to examples illustrating the impact of varying the coarse-graining scheme. Our approach unifies macroscopic and
stochastic thermodynamics in a genuinely
quantum framework, laying the basis for a versatile, experimentally friendly toolbox to analyze complex
quantum dynamics.
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Fluid Dynamics
Coherence does not always imply causality in wall-bounded turbulence
Peng E S Chen and Javier Jimenez
Compact structures of intense tangential Reynolds stress (Q events) are well-known components of wall-bounded
turbulence, and have been shown to be coherent because they approximately govern their own
evolution. It has therefore often been assumed that they also are causally significant, in the sense that they explain the
evolution of the incoherent component of the flow, which could thus be modeled as a superposition of structures. Since strong events typically only fill a small percentage of the total flow volume, this is also cited as a reason for considering structures as targets for efficient engineering flow control. This paper shows that the causality assumption does not hold in general. Only about half of the structures identified in the flow are causally more significant than an equivalent volume of incoherent
turbulence. To explain this variability, feature-based analysis and conditional averaging are performed. For wall-attached Q2 events and wall-detached structures, causally enhanced events are characterized by elevated strain rate and spanwise vorticity. These signatures are traced to intense upstream strain regions generated by the interaction of Q4-like motions impinging on Q2 events. For wall-attached Q4 events, the dominant indicators are instead the wall-normal and streamwise vorticity components; enhanced causal significance is associated with strong wall-normal vorticity. These findings show that quadrant events cannot be treated as a dynamically homogeneous class in causal analyses. Their causal significance depends strongly on the local flow environment, emphasizing the need to interpret coherent structures in terms of their interactions with the surrounding
turbulence.
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Cosmology and Nongalactic Astrophysics
Cosmological Constraints on the DGP Model in light of DESI DR2 2025 Data
Xinyi Dai, Yupeng Yang and Yicheng Wang
We present updated constraints on both flat and non-flat Dvali-Gabadadze-Porrati (DGP) cosmological models using the latest
baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument Data Release 2 (DESI DR2), in combination with
cosmic chronometer (CC), Type Ia
supernova (SNIa), and
cosmic microwave background (CMB) distance priors. For the non-flat DGP model, we obtain $H_0 = 64.05 \pm 0.27\, \rm{kms^{-1}Mpc^{-1}}$, $\Omega_m = 0.3264 \pm 0.0043$, and $\Omega_k = 0.0088 \pm 0.0016$, corresponding to a transition
redshift $z_t \sim 0.41$. For the flat case, the constraints are $H_0 = 63.28 \pm 0.25\, \rm{kms^{-1}Mpc^{-1}}$ and $\Omega_m = 0.3303 \pm 0.0036$. In both scenarios, the inferred Hubble constant is significantly lower than the Planck $\mathrm{\Lambda}$CDM value, indicating that the DGP framework does not alleviate the Hubble tension. Current observations strongly disfavor the DGP framework, primarily due to its inability to simultaneously accommodate DESI BAO and CMB constraints.By incorporating the latest high-precision DESI observations within a unified analysis framework, this work provides updated and more stringent limits on the DGP scenario, offering a consolidated assessment of its viability in the context of current cosmological data.
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Chemical Physics
Serially Improved GTOs for Molecular Applications (SIGMA): basis sets from monovalent ions
Ignacio Ema, Guillermo Ramirez, Rafael Lopez et al. (+1 more)
A new family of ionic basis sets, denoted i{\sigma}XZ1, is presented for molecular calculations on systems containing monovalent ions. The basis sets extend the SIGMA family by explicitly accounting for the different electronic structure of cations and anions. Auxiliary basis sets for resolution-of-the-identity calculations are also developed for the Coulomb term. The performance of the proposed basis sets is assessed for alkali-halide clusters. Compared with conventional basis sets, i{\sigma}XZ1 provides an accurate description of structural, energetic, and electronic properties while showing remarkable robustness against near-linear dependencies, allowing stable calculations on systems containing up to 792 NaCl units. These features make the i{\sigma}XZ1 family a reliable and efficient alternative for large-scale calculations on ionic systems.
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All authors Ignacio Ema, Guillermo Ramirez, Rafael Lopez, Jose Manuel Garcia-de-la-Vega
High Energy Physics (Phenomenology)
Tensor-polarized parton distribution functions of the deuteron by a convolution model
S. Kumano and Kenshi Kuroki
Tensor-polarized parton distribution functions (PDFs) are calculated for the deuteron by using a convolution formalism, where the tensor-polarized PDFs are given by the corresponding nucleon's unpolarized PDFs convoluted with the tensor-polarized nucleon momentum distribution in the deuteron. These distributions are obtained at $Q^2=2.5$ GeV$^2$ in order to compare with the tensor-polarized PDFs which were determined by HERMES $b_1$ data. The obtained distributions are very different from the ones determined from the HERMES data, which indicates further studies are needed to clarify the difference, possibly by considering a new mechanism beyond the simple bound system of a
proton and a
neutron. The obtained PDFs $\delta_T q $ and $\delta_T \bar q$ are converted to the PDFs of the Trento convention $f_{1LL}^{\, q}$ and $f_{1LL}^{\, \bar q}$, and they are used for estimating the twist-3 PDFs $f_{LT}^{\, q}$ and $f_{LT}^{\, \bar q}$ by using a Wandzura-Wilczek-like relation. Because deep-inelastic-scattering experiments are under preparation for structure functions with a tensor-polarized deuteron target at the Thomas Jefferson National Accelerator Facility, and a Drell-Yan experiment will be possible at
hadron accelerator facilities, such as the
Fermi National Accelerator Laboratory, the obtained tensor-polarized PDFs will be tested experimentally.
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High Energy Physics (Theory)
Quantum field nucleating and Wigner functions
Joonas Hirvonen
We present a novel real-time framework for the decay of metastable states in
quantum field theories using Wigner functions. The framework introduces a nonperturbative nucleation rate formula that captures both
quantum tunneling and over-the-barrier nucleation, alongside steps to evaluate it perturbatively. We apply it to a simple thermal example with direct relevance to current analog experiments. Our derived one-loop nucleation rate fundamentally differs from the widely cited high-temperature result by Linde: The prefactor contains
quantum effects and also asymptotes to a differing form at high temperatures, where the
quantum effects become negligible. Rather, the result is a generalization of Affleck's rate formula to
quantum field theories, asymptoting to the effective field theory approach, and Langer's rate, at high temperatures. The example also reveals that the high-temperature side of the “
quantum-to-classical” transition of thermal
vacuum decay is still inherently
quantum mechanical, even though the bounce background possesses the classical, $\mathrm{O}(d)\times S^1$,
symmetry.
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Plasma Physics
Tens of MeV, collimated, bright fluxes of protons from ordered nano-structured targets in ultra-relativistic laser-matter interaction
Sagar Dam, Stefania Ionescu, Jian Fuh Ong et al. (+20 more)
Laser-driven
proton acceleration from nanostructured solid targets has been extensively studied, yet its performance under realistic temporal contrast conditions at petawatt-class facilities remains an open question. We present an experimental investigation of
proton generation from nanostructured and flat solid targets performed at the ELI-NP facility using femtosecond
laser pulses at peak intensities of $\sim 3\times10^{21}$ \wcm.
Proton spectra are compared for two contrast regimes: $\sim 10^{-10}$ without
plasma mirror and $\sim 10^{-13}$ with single
plasma mirror. Importantly, measurable enhancement in the cutoff energy persists for the nanowire targets at both contrast levels, indicating robustness of nanowire targets against moderate pre-pulse intensities. Alongside, study of energy resolved angular distribution reveals that nanowires promote more directional emission with higher flux of high-energy
protons along the target normal, while flat targets produce broader angular distributions. The results are well supported and explained by 3D particle-in-
cell simulations.
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All authors Sagar Dam, Stefania Ionescu, Jian Fuh Ong, Ameya Parab, Sk Rakeeb, Hideaki Habara, Gabriel Cojocaru, Vojtěch Horný, Dmitrii Nistor, Saidbek Norbaev, Rudrajyoti Palit, Daniel Popa, Deepak Sangwan, Klaus Spohr, Bianca Stan, Antonia Toma, Lucian Tudor, Daniel Ursescu, Adrian Vatcu, Keita Yamanaka, Prashant Kumar Singh, Kazuo A. Tanaka, G. Ravindra Kumar
Instrumentation and Detectors
Energy, time, and position resolution measurements of an array of large tapered LYSO crystals
O. Beesley, J. Carlton, D. Ding et al. (+19 more)
We report on the performance of six custom-made tapered LYSO
crystals of unprecedented volume, which constitute a sector of the 19 radiation length electromagnetic calorimeter planned for the PIONEER experiment. The longitudinal response uniformity of each
crystal was measured using radioactive sources before characterizing the energy and time resolution of the
crystals in an array using a 20 to 80 MeV positron beam at the Paul Scherrer Institute. The array demonstrated an energy resolution better than 2 % for energies above 40 MeV and a time resolution better than 140 ps for energies above 30 MeV. The spatial resolution was measured in the central region of the array to be 5.06 mm in x and 5.20 mm in y at 70 MeV. The measured properties satisfy the key design parameters of the PIONEER calorimeter for the measurement of rare pion decays.
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All authors O. Beesley, J. Carlton, D. Ding, S. Foster, K. Frahm, T. Frank, L. Gibbons, D. Goeldi, T. Gorringe, D. W. Hertzog, S. Hochrein, J. Hui, E. Klemets, J. LaBounty, J. Liu, P. Lopez Maggi, W. Osar, R. Roehnelt, P. Schwendimann, W. Shuai, A. Soter, E. Swanson
Nuclear Theory
Medium-mass nuclei with neural quantum states
Bryce Fore, Jane Kim, Alessandro Lovato et al. (+1 more)
We compute ground-state energies and charge radii of light- to medium-mass
nuclei with up to $A=58$ nucleons, leveraging a variational Monte Carlo method based on Pfaffian-Jastrow neural
quantum states. To further understand which elements of the
nuclear Hamiltonian are "essential" to predict binding energies and charge radii across the
nuclear chart with few-percent errors, we consider different interactions inspired by pionless effective field theory. Specifically, in addition to model "o" of [Phys. Rev. C 103, 054003 (2021)], we study the impact of charge-
symmetry-breaking and charge-dependent terms in the nucleon-nucleon force, as well as $p$-wave contributions, which have been found to be critical for the stability of $p$-shell
nuclei. In addition to its intrinsic interest, our work assesses the performance of neural
quantum states in the medium-mass regime and examines the impact of these interaction modifications. Using the resulting ground-state simulations, we analyze the computational scaling of variational Monte Carlo with neural
quantum states as a function of system size and computational resources, enabling projections for future large-scale calculations.
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All authors Bryce Fore, Jane Kim, Alessandro Lovato, Anthony Tropiano
Physics and Society
I see you, do you see me? Perception-based crowdedness and behavioral responses in pedestrian dynamics
Igor Hołowacz and Pratik Mullick
Pedestrian traffic is commonly characterized using local density, yet the interactions experienced by individuals depend on the relative positions and perceptual relevance of surrounding pedestrians. This raises the question of whether behavioral relationships inferred from local crowdedness are robust to the representation of perceptual anisotropy, and how interaction geometry shapes pedestrian adaptation over time. We analyze experimental pedestrian crossing flows over angles from 0 to 180 degrees using a distance-weighted measure of local crowdedness. Perceptual anisotropy is varied by reducing the contribution of pedestrians outside the focal pedestrian's field of view. We examine the temporal
evolution of crowdedness and its relationships with velocity, directional deviation, and acceleration. Anisotropy primarily changes the numerical scale of crowdedness, while the qualitative dynamics, temporal progression, and crossing-angle dependence remain largely preserved. Pedestrians deviate appreciably from their expected group directions, but changes between successive walking directions remain small, indicating adaptation through smooth, incremental corrections rather than abrupt turns. Acceleration dynamics reveal an asymmetry between disruption and recovery: initial deceleration varies strongly with crossing geometry, whereas recovery accelerations are more similar across angles. Non-retracing trajectories in the behavioral phase spaces show that similar instantaneous conditions can correspond to different phases of the interaction. Overall, interaction geometry has a stronger influence on the organization of crossing flows than the perceptual weighting used to quantify local crowdedness. More broadly, dynamic fundamental diagrams provide a more complete characterization of transient pedestrian interactions than conventional relationships based on instantaneous state variables alone.
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Instrumentation and Detectors
Laser-Induced Fluorescence for measuring salt mass fraction in evaporating saline solutions
Antoine Dumain, Florine Giraud, Ophélie Caballina et al. (+2 more)
A non-intrusive optical diagnostic based on
Laser-Induced Fluorescence (LIF) is developed for measuring salt mass fraction in highly concentrated aqueous solutions relevant to absorption heat pump applications. The method relies on a systematic
redshift of the fluorescence emission spectra of several dyes, likely induced by an increase of ionic strength with salt mass fraction. A two-color ratiometric approach, based on the ratio of fluorescence intensities in two spectral bands, enables robust mass fraction measurements. This study demonstrates that the techniques is not limited to LiBr but also NaCl, relevant for desalination applications. In parallel, fluorescence lifetime measurements using Time-Correlated Single
Photon Counting (TCSPC) reveals that fluorescence lifetime is also affected by the LiBr mass fraction, allowing an alternative measurement technique. For both techniques, many dyes are tested and are compared in terms of salt mass fraction sensitivity. Both techniques are validated independently through comparison with shadowgraphbased measurements during evaporation of droplets. Good agreement is obtained in
liquid-phase conditions over a wide range of salt mass fractions, confirming the reliability of the proposed diagnostics. Key sources of uncertainty including temperature, reabsorption effects and phase changes has been identified and analyzed. Finally, preliminary results demonstrate the potential extension of the approach toward planar imaging of evaporating droplets and more complex multiphase flows. The methodology provides a basis for future quantitative diagnostics of heat and mass transfer in desorption systems such as falling-films.
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All authors Antoine Dumain, Florine Giraud, Ophélie Caballina, Benoit Stutz, Guillaume Castanet
Plasma Physics
Comparison of DBS measurements of turbulence spectra by vertical-displacement and poloidal-angle scans using the Scotty synthetic diagnostic
Y.T. Tan, V. Hall-Chen and T. Rhodes
Doppler backscattering (DBS) measures electron density fluctuations. The measured wavenumber is typically varied by changing the probe beam poloidal launch angle. As most DBS systems are unable to steer during a shot, the shot is repeated and the poloidal angle is changed intershot. An alternative method is to keep the DBS launch angle fixed and move the
plasma up and down instead, enabling a range of wavenumbers to be measured within a single shot. We call this the bouncing ball method. We use the Scotty synthetic diagnostic (
Hall-Chen, 2022) to evaluate the similarities and differences between these two approaches. Both approaches are capable of measuring a similar range of fluctuation wavenumbers as well as radial locations. However, the vertical-displacement scan has a larger range of measured poloidal locations than the poloidal-angle scan. Using the same synthetic
turbulence spectrum as input, we show that the two approaches are expected to have different backscattered powers due to different instrumentation functions. When mismatch attenuation is accounted for via a synthetic diagnostic, the vertical-displacement scan can provide comparable radial and wavenumber coverage while reducing reliance on shot-to-shot repeatability. These results establish vertical-displacement scan as a practical route to single-shot DBS wavenumber spectra.
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High Energy Physics (Phenomenology)
Hunting for new physics in $B$ meson $b \to u$ transitions: A fresh look with Belle II data
Pietro Colangelo, Fulvia De Fazio, Maria Letizia Di Cuia et al. (+1 more)
We present an analysis of the decays $B^- \to \ell^- {\bar \nu}_\ell$, $\bar B^0 \to \pi^+ \ell^- {\bar \nu}_\ell$, and $B^- \to \rho^0 \ell^- {\bar \nu}_\ell$ leveraging the precise measurements of binned differential branching fractions recently reported by the Belle II Collaboration for the semileptonic modes. We adopt a generalized low-energy
Hamiltonian that incorporates all dimension-six operators with left-handed
neutrinos – consistent with the Standard Model effective field theory (SMEFT) – featuring complex,
lepton-
flavor-dependent Wilson coefficients. For three representative values of $|V_{ub}|$, we perform a fit to the measured $q^2$-binned observables to constrain the coupling parameter space and determine the corresponding confidence regions. Finally, we perform a global fit for the three decay channels, determining $|V_{ub}|$ together with the new physics couplings.
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All authors Pietro Colangelo, Fulvia De Fazio, Maria Letizia Di Cuia, Davide Milillo
General Relativity and Quantum Cosmology
Eccentricity-Modulated Phase Degeneracy and Distinguishability between Dark Matter and Accretion Disk Environmental Effects in EMRIs
Tian-Hao Wu and Shu-Jun Rong
Extreme mass-ratio inspirals (EMRIs) are sensitive probes of weak environmental effects around massive black holes, since such effects can accumulate into observable gravitational-wave phase shifts. In this work, we study the phase degeneracy between dark matter
halos and
accretion disks in eccentric EMRI waveforms. We model the dark matter (DM) environment with NFW and Beta
halo profiles, and describe the disk using a thin $\alpha$-disk model. Their distinguishability is quantified through eccentricity-dependent phase diagnostics and the residual signal-to-noise ratio (SNR) in the LISA band. Our results show that DM-induced dephasing depends only weakly on the initial eccentricity $e_0$, whereas disk-induced dephasing is strongly suppressed as $e_0$ increases. The distinguishability time exhibits a smooth and weakly non-monotonic dependence on the initial eccentricity, while being more strongly controlled by the environmental strength. For the
benchmark systems considered here, the DM–disk waveform difference can be detectable by LISA, and $e_0$ can serve as an auxiliary diagnostic in addition to the observation duration.
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Classical Physics
Mean field homogenization schemes for composites with prolate and oblate spheroids: use of the orientation tensors and computation of the strain second-moments
Antoine Martin
In this document we provide the homogenized stiffnesses from Mori-Tanaka scheme and Ponte-Castañeda and Willis scheme applied to composites with spheroidal inclusions. The inclusions can be prolate spheroids ('fibers') or oblate spheroids ('penny-shapes'). We show how to compute the homogenized stiffnesses for particular distribution of spheroid orientations, using the second-order and fourth-order orientation tensors. We also provide formulas to compute the derivatives of these quantities w.r.t. the material parameters, which is of particular interest for computing the second-moments of the strains.
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Astrophysics of Galaxies
Performance of morphological classifiers for galaxy mergers compared to current machine learning methods
Aidan P. Cotter, William J. Pearson, Subhrata Dey et al. (+3 more)
Aims. Non-parametric morphological statistics can be used for efficient classification of
galaxy mergers. This work aims to compare the performance of morphological merger classifiers to state-of-the-art machine learning (ML) models. A secondary aim is to produce updated criteria for mergers based on non-parametric morphological statistics. Methods. The Gini coefficient (G), $M_{20}$ statistic, and concentration ($C$) were calculated for mock Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) images based on the IllustrisTNG and Horizon-AGN simulations, and observations from HSC-SSP. The IllustrisTNG images were used to find the line which best separates mergers and non-mergers in 2D morphological space with a Markov Chain Monte-Carlo (MCMC) method. Results. Based on the MCMC results, we classified
galaxies with $G>(-0.267\pm0.081)M_{20}+(0.143\pm0.012)$ or $G>(0.162\pm0.048)C-(0.149\pm0.12)$ as mergers, these criteria had precisions of 69.5% and 72.3% respectively when applied to previously unseen IllustrisTNG mock HSC-SSP images. The precisions of the morphological classifications are consistent with state-of-the-art ML methods. The morphological classifiers were found to be effective at selecting only pre-mergers; post-merger
galaxies are indistinguishable from non-mergers in terms of their $G$, $M_{20}$, and $C$ values. Morphological classifiers displayed a similar robustness to new data to ML methods up to a
redshift of $\sim0.52$ and maintained robustness better than ML methods based on convolutional neural networks in the
redshift range $0.52<z<1$. Conclusions. This work presents updated morphological classifiers which achieve similar precisions to ML based merger classifiers with a high robustness to new data. New morphological statistics are needed to identify the features of post-merger
galaxies.
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All authors Aidan P. Cotter, William J. Pearson, Subhrata Dey, Berta Margalef-Bentabol, Alejandro Guzmán-Ortega, Vicente Rodriguez-Gomez
Nuclear Theory
The impact of nuclear uncertainties on the p-process nucleosynthesis in Supernovae
S. Martinet, S. Goriely and A. Choplin
The p-process is responsible for the production of the stable
neutron-deficient
nuclei heavier than iron observed in the
solar system. However, important
nuclear uncertainties still limit our understanding of this nucleosynthesis process. Among the most significant are the
nuclear level densities (NLDs) and
photon strength functions (PSFs) entering the calculation of photodisintegration rates under
supernova conditions. We investigate both model (systematic) and parameter (statistical) uncertainties affecting NLDs and PSFs and quantify their impact on p-process nucleosynthesis in type-Ia and type-II
supernovae. Correlated model uncertainties are estimated using several NLD and PSF models that reproduce available experimental observables. Uncorrelated parameter uncertainties are evaluated with a backward-forward Monte Carlo approach, in which parameter variations are constrained by measured reaction rates before being propagated to unknown cross sections of
neutron-deficient
nuclei. The resulting uncertainties are propagated through p-process calculations while preserving model correlations. To identify the reactions driving abundance uncertainties, we combine regularized linear-response modeling, stability analysis, and contribution and interaction decompositions. We find that photoneutron-emission uncertainties dominate the overall uncertainty budget. The leading source of uncertainty arises from local parameter variations still compatible with current experimental constraints, highlighting the lack of constraining
nuclear data in the
neutron-deficient region. For many p-
nuclei, the dominant contribution originates either from the photoneutron emission of the p-
nucleus itself or from a nearby $(\gamma,n)$ reaction along the same isotopic chain. While improved
nuclear models remain important, many key reactions involve stable or near-stable
nuclei and should be experimentally accessible.
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High Energy Physics (Phenomenology)
Exclusive $J/\psi$ photoproduction in photon-proton diffractive scattering: A light-front Hamiltonian approach
Xiaoyi Wu, Zhi Hu, Chandan Mondal et al. (+5 more)
We investigate the cross-section for exclusive $J/\psi$ production in
photon-
proton diffractive scattering within the Basis Light-Front Quantization (BLFQ) framework. The leading-order contribution to this process is well approximated by the charge conjugation-even two-
gluon (“pomeron") exchange mechanism in the dipole model, which factorizes the total amplitude into the dipole scattering amplitude and the convolution of the $J/\psi$ and
photon light-front wave functions (LFWFs). We express the dipole scattering amplitude as the
matrix element of
gluon field operators inserted between
proton states, with the element being sensitive to the
proton LFWFs and the Bjorken scaling variable, $x$. The
proton and $J/\psi$ LFWFs are obtained by diagonalizing their respective light-front
Hamiltonians within the BLFQ approach, while the virtual
photon LFWFs are employed from perturbative QCD. Our results provide initial conditions for the Balitsky-Kovchegov (BK) equation, which can be used to probe the
proton structure at smaller Bjorken scales. This work offers valuable theoretical insights for future electron-ion
collider experiments.
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All authors Xiaoyi Wu, Zhi Hu, Chandan Mondal, Jiangshan Lan, Siqi Xu, Jiatong Wu, Xingbo Zhao, James P. Vary
High Energy Physics (Theory)
Cherednik integrable system: eigenfunctions at generic eigenvalues
A. Mironov, A. Morozov and A. Popolitov
Symmetric Macdonald
polynomials of $N$ variables provide eigenfunctions of the $N$-body trigonometric Ruijsenaars-Schneider integrable system at particular
eigenvalues. In order to construct eigenfunctions with arbitrary
eigenvalues, M. Noumi and J. Shiraishi used a recursion in $N$ (branching rule) for the symmetric Macdonald
polynomials and analytically continued them. This generated a power series, which is a part of triad (universal solution). In the present paper, we demonstrate that a similar procedure is available for another integrable system, $N$-body Cherednik integrable system inspired by the DAHA of type $A$, which has non-symmetric Macdonald
polynomials as its
polynomial eigenfunctions. However, in this system, the generic eigenfunction is more complicated: it is not just a simple power series as in the Noumi-Shiraishi case, but has an involved structure with $N!$ branches, each of them being a sum over the Weyl chambers of power series of the Noumi-Shiraishi type. As an illustration, we also provide explicit formulas for particular cases.
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