Earth and Planetary Astrophysics
The Dynamics of Planetary Ejection
Malena Rice, William DeRocco and Sean N. Raymond
The ubiquity of free-floating
planets inferred from microlensing and direct imaging surveys suggests that planetary ejection—a process in which
planets initially born encircling a
stellar host become gravitationally unbound—is common. Four overarching mechanisms have been proposed to induce planetary ejection: close approaches of neighboring
planets, instabilities in binary or multi-
star systems,
stellar and planetary flybys, and post-main-sequence
stellar evolution. Here we review the mechanisms underlying planetary ejection, as well as predictions derived from each. Current and upcoming microlensing surveys offer the potential to test existing models and distinguish between planetary ejection mechanisms, offering further insight into the demographic-level architectures of
exoplanets across
stellar environments.
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Physics and Society
Discovery is not the opposite of application
Hiranya V. Peiris
Restructuring research funding as a choice between discovery and application gets the economics wrong, the evidence wrong and the people wrong.
Quantum Physics
Fault-Tolerant Heisenberg-Limited Quantum Sensing
Lorcan O. Conlon, Yu-Xin Wang, Erfan Abbasgholinejad et al. (+3 more)
Quantum sensors hold great promise for achieving better sensitivity in the measurement of physical quantities compared to their classical counterparts. However, the conditions under which
quantum advantage in sensing can be achieved are rather restrictive, and most
quantum enhancements in sensing are lost in the presence of noise, errors, or a poorly calibrated system. To overcome these limitations, we are motivated to import ideas from fault-tolerant
quantum computing to
quantum sensing. Specifically, we consider a
qubit noise model where the probability of phase-flip errors is exponentially smaller (in
qubit number) compared to the probability of bit-flip errors that occur with probability $p$. For this noise structure, we demonstrate that, given a total sensing time $T$, Heisenberg scaling can be attained for times up to $T\propto 1/p^{(N+1)/2}$ for a $N$-
qubit repetition code, in contrast with $T\propto 1/p$ without using a fault-tolerant sensing protocol.
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All authors Lorcan O. Conlon, Yu-Xin Wang, Erfan Abbasgholinejad, Victor V. Albert, Michael J. Gullans, Alexey V. Gorshkov
Strongly Correlated Electrons
Shape of Wigner Crystals and Hole Self-Doping in a Mexican-Hat Dispersion
Minho Luke Kim and Xiao-Gang Wen
We study Wigner
crystals (WCs) induced by a strong Coulomb interaction from the ring-like
Fermi surface of a Mexican-hat dispersion $\epsilon_k= c_2k^2+c_4k^4$. We design orbital shape in order to minimize the energy of the WC, and find that a low ground-state energy requires an orbital shape with a depletion of electrons near $k=0$. To capture the Coulomb-induced correlations, we include a Jastrow factor as well as a factor describing the correlation between electrons and doped vacancies. Using variational Monte Carlo calculations, we calibrate the effective band parameters $c_2$ and $c_4$ to reproduce the two transitions observed experimentally as the electron density is lowered: from a
spin-valley-polarized
Fermi liquid with a disk-like
Fermi surface, to one with a ring-like
Fermi surface, and finally to a WC. We find that, even with an optimized orbital shape that depletes electrons near $k=0$, a WC with hole self-doping near $k=0$ can still be energetically favorable near the WC transition, provided that the electron-vacancy correlation is included. We also estimate the dispersion of the doped hole.
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High Energy Physics (Theory)
Dynamics of nucleation in thermal phase transitions
Oliver Gould, Joonas Hirvonen, Andrey Shkerin et al. (+1 more)
We study dynamical effects during nucleation in thermal first-order phase transitions in field theory. Focusing on the classical regime of the decay of a metastable state, we present the general formula for the thermal decay rate including the dynamical prefactor and give a recipe for its systematic evaluation. We describe the physical mechanism which reduces the actual thermal decay rate with respect to the statistical rate obtained in
equilibrium theory. We also discuss the thermality conditions ensuring the existence of a steady-state thermal rate, in which case our formula is exact up to exponentially small corrections. We show that it reproduces the known results for the nucleation rate in
stochastic mechanics and field theory, and allows us to unify and go beyond them. We illustrate this in real-time numerical simulations of simple field theory models. We observe significant non-perturbative contributions which can dominate the dynamical prefactor in weakly-coupled field theories at moderate exponential suppression of the decay rate. We explore the connection of these non-perturbative effects to oscillons. Notably, our numerical method requires exponentially less computing time than direct simulations of decays and is thus applicable to systems with arbitrarily strong exponential suppression. Finally, we discuss small or poorly thermalized systems when the thermality conditions are violated and the steady-state rate does not exist.
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All authors Oliver Gould, Joonas Hirvonen, Andrey Shkerin, Sergey Sibiryakov
Data Analysis and Statistics
Lossless Compression Performance for PETRA III Datasets
Malte Buschmann, Yannis Schumann, Christian Voss et al. (+2 more)
Large-scale research facilities increasingly face the challenge of managing rapidly growing data volumes while maintaining sustainable archival infrastructures. We present the first comprehensive study of data heterogeneity and lossless general-purpose compression performance for representative
datasets from the PETRA III synchrotron radiation source. Our corpus comprises more than 212 TiB of raw and processed data from ten experiments spanning multiple beamlines, detector systems, and scientific workflows. We observe substantial heterogeneity both between and within experiments, resulting in compression ratios that vary by more than two orders of magnitude across
datasets. Evaluating nine widely used lossless compression tools, we find that Zstandard and LZ4 consistently occupy the high-throughput region of the Pareto front, whereas ZPAQ achieves the highest compression ratios. Furthermore, heterogeneous compression strategies that adapt compressor choice to the underlying file category outperform uniform compression policies. Extrapolating from the benchmarked
datasets to the full PETRA III non-tape storage system, we estimate achievable compression ratios ranging from approximately 1.6 at $\sim$900 MiB/s throughput to 2.1 at $\sim$2 MiB/s. These results provide a quantitative basis for future archival and storage decisions at PETRA III, its future successor, PETRA IV, and other large-scale scientific facilities.
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All authors Malte Buschmann, Yannis Schumann, Christian Voss, Tigran Mkrtchyan, Philipp Neumann
Strongly Correlated Electrons
Ahmed Abouelkomsan, Filippo Gaggioli, Daniele Guerci et al. (+1 more)
Experiments on rhombohedral
graphene have uncovered an extraordinary wealth of correlated
quantum phases - from
chiral superconductors to electronic
crystals - all within a single family of atomically thin materials. Here, we introduce a simple indicator, derived from the noninteracting band dispersion, that identifies strongly correlated regions in the phase diagram of rhombohedral
graphene as a function of carrier density and displacement field. We develop a neural-network variational Monte Carlo method, combined with Hartree-Fock theory, to solve the interacting ground states. Our calculation reveals a variety of electron
crystals with no classical analog. These include, at increasing density: Wigner
crystal, self-doped Wiger
crystal, as well as ”anticrystal”, a
lattice of holes in an electron
liquid. We discuss their experimental manifestations and possible connection to superconductivity.
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All authors Ahmed Abouelkomsan, Filippo Gaggioli, Daniele Guerci, Liang Fu
High Energy Physics (Phenomenology)
The flavour of SU(15) composite quarks and leptons
Benoît Assi, Ryan Plestid, Amartya Sengupta et al. (+1 more)
We study the flavour structure of an $SU(15)_p$ confining
chiral gauge theory in which the Standard Model (SM)
quarks,
leptons, and
Higgs emerge as composite bound states. The couplings of two scalar fields in the conjugate antisymmetric ($\overline{\mathbf{105}}$) and conjugate symmetric ($\overline{\mathbf{120}}$) representations of $SU(15)_p$ provide two $SU(4)_F$ flavour-breaking spurions that generate both the SM Yukawa couplings and the flavour-changing processes. The up and down Yukawa
matrices are tightly-correlated due to a "right-handed isospin"
symmetry, which predicts a trivial CKM
matrix in the absence of spontaneous
symmetry breaking. The
lepton Yukawas are correlated with the
quarks due to a common source of flavour spurions. With a judicious Froggatt-Nielsen-like texture for the two flavour spurions we find that a
benchmark fit with $\mathcal{O}(1)$ non-perturbative coefficients reproduces all six
quark masses, three charged
lepton masses, and the CKM
matrix. The same spurions mediate charged
lepton flavour violation, neutral
meson mixing, rare kaon decays, and induce electric dipole moments. We compare the reach on the compositeness scale $\Lambda_{\rm pre}$ across these observables in the numerical
benchmark and find that the electron EDM and $K^0$-$\bar{K}^0$ mixing provide the strongest sensitivity, reaching $\mathcal{O}(10^4)$ TeV, the lower end of the range probed by
proton decay, while $\mu\to e\gamma$, $D^0$-$\bar{D}^0$ mixing, and $\mu$-$e$ conversion give complementary reach at $10^2$-$10^3$ TeV. The projected electron EDM sensitivity extends this to $\mathcal{O}(10^6)$ TeV, beyond the reach of planned
proton decay searches.
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All authors Benoît Assi, Ryan Plestid, Amartya Sengupta, Jure Zupan
Lattice Field Theory
Arbitrary-Distance Quantum Error Correction with Gauss's Law for $\mathbb Z_2$ Lattice Gauge Theory
Neel S. Modi, Lento Nagano, Masazumi Honda et al. (+2 more)
It has previously been shown by Rajput, Roggero, and Wiebe that $\mathbb Z_2$ Gauss's law constraints can be used to build efficient
quantum error-correcting codes (QECCs) that are robust against arbitrary single-
qubit errors. In this work, we generalize the construction to be robust against arbitrary $t$-
qubit errors, where $t$ is any positive integer. This includes a derivation of the optimal Gauss's law code within the considered family by minimizing the number of physical
qubits required for a given code distance. Finally, we compare our codes against other efficient QECCs on metrics such as the number of physical
qubits, the locality of the encoded
Hamiltonian, and the logical error rate in the code capacity setting. Compared to using a domain-agnostic code for every
lattice degree of freedom, we find that the Gauss's law code primarily excels at reducing the locality of the encoded
Hamiltonian. Moreover, the physical
qubit overhead is also reduced for $t \le 3$ (distance $d \le 7$).
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All authors Neel S. Modi, Lento Nagano, Masazumi Honda, Nobuyuki Yoshioka, Christian W. Bauer
Cosmology and Nongalactic Astrophysics
Evidence for a thermal pressure deficit in galaxy groups from the tSZ effect and weak lensing
Jared Siegel, Alexandra Amon, Jenny E. Greene et al. (+3 more)
Measurements of the thermal Sunyaev-Zel'dovich (tSZ) effect have yet to form a consistent picture of the thermodynamic state of the gas in the intracluster medium: their interpretation is complicated by foreground contamination and uncertain
halo masses. We present new measurements of the tSZ effect around the Dark Energy Spectroscopic Instrument (DESI) Luminous Red
Galaxy (LRG) sample, together with
galaxy-
galaxy lensing (GGL) measurements that enable a like-with-like comparison to state-of-the-art hydrodynamical simulations. We robustly isolate the tSZ signal by directly modeling the
dust and
radio emission of the target
galaxies using the Atacama Cosmology
Telescope (ACT) single-channel temperature maps, substantially reducing uncertainties from astrophysical foregrounds. Across
halo masses $M_{500}=10^{13}-10^{14}~M_\odot$ and
redshifts $0.4<z<1$, we find that the fiducial 1 Gpc$^3$ FLAMINGO simulation significantly overpredicts the observed tSZ signal at $\lesssim3'$ (i.e., $\lesssim 4\,R_{500}$ at $z=0.7$). Even the simulation with the strongest gas expulsion—which successfully reproduces the gas density inferred from kinetic SZ measurements of the same
galaxy sample—overpredicts the thermal pressure. Because the strongest feedback model already reproduces the observed gas density, the remaining discrepancy is difficult to explain with additional gas depletion alone. Instead, current hydrodynamical simulations appear to overpredict the thermal pressure of
galaxy groups by a factor of two, pointing toward missing non-thermal pressure support or significant departures from hydrostatic
equilibrium.
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All authors Jared Siegel, Alexandra Amon, Jenny E. Greene, Ian G. McCarthy, Eliot Quataert, William Coulton
Quantum Physics
Realization of a Quantum Topological Photon Pump
Qianao Yue, Bernardo Barrera, Martin Ritter et al. (+4 more)
Topological pumps transfer charge or energy at quantized rates determined solely by band
topology, independent of the details of the control fields.
Photon pumps operating on this principle could enable the robust preparation of non-classical states in a
quantum cavity, even in the presence of control imperfections, but have not been directly observed. We present the first experimental observation of a topological
photon pump, using a transmon
qubit coupled to a microwave cavity. The pump operates in the
quantum regime, pumping up from the
vacuum state up to $\approx 7$
photons, and produces demonstrably non-classical cavity states for the first few cycles.
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All authors Qianao Yue, Bernardo Barrera, Martin Ritter, David M. Long, David A. Lane, Anushya Chandran, Alicia J. Kollár
High Energy Physics (Phenomenology)
Ubiquitous Corotation of Dark Matter Halos: Implications for Direct Detection
Dylan Folsom, Carlos Blanco, Mariangela Lisanti et al. (+1 more)
Cosmological simulations have recently begun to quantify the
halo-to-
halo variance in the phase-space distribution of dark matter around the Sun. We use a sample of nearly one hundred Milky Way-like
galaxies from the TNG50 simulation to determine what aspects of this variance control the predictions for dark matter direct detection. Contrary to the isotropy assumed in the standard
halo model, we find the dark matter median azimuthal velocity is nonzero and preferentially corotating, i.e., in the direction of the baryonic disk's rotation, ranging from 6-70 km/s (16th-84th percentile). This corotation suppresses predicted scattering rates in laboratory experiments searching for dark matter lighter than 50 GeV and significantly affects the expected daily modulation amplitude for directional detectors. In particular, this induces a 21% uncertainty on the upper limit of the dark matter-nucleon interaction cross section at peak sensitivity for a typical isotropic ton-scale experiment. This uncertainty is not irreducible, however: it is strongly correlated with the rotational velocity. If studies of the Milky Way's formation history determine the rotation speed, this astrophysical uncertainty is reduced to 7%.
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All authors Dylan Folsom, Carlos Blanco, Mariangela Lisanti, Mark Vogelsberger
Quantum Physics
Optimal Decoding for Measurement-Based GHZ State Preparation: The Maximum-Utility Decoder
Misha Yutushui, Theo Haas and Simon Trebst
The meticulous preparation of macroscopic Greenberger-Horne-Zeilinger (GHZ) states provides a foundational resource for
quantum technologies such as metrology, cryptography, and fault-tolerant codes. While state-of-the-art measurement-based protocols offer efficient low-depth execution, their performance can be bottlenecked by conventional decoders, such as minimum weight perfect matching (MWPM) or even maximum-likelihood decoding (MLD), which optimize for $binary$ logical recovery and fail to maximize the $continuous$ long-range order characteristic of a GHZ state for two-dimensional geometries. Here we overcome this limitation by framing the decoding problem as minimum
Bayesian risk inference, introducing a general paradigm that maximizes the expected ${utility}$ of the decoded state. Implementing this maximum-utility approach, we construct an
algorithm that achieves the highest possible per-shot decoded
quantum order and thereby establish an optimal decoding strategy for measurement-based GHZ state preparation. To improve its computational efficiency, we design a scalable two-stage decoder, which first encodes the syndromes into the edge weights of MWPM and then refines the result with a convolutional neural network trained to maximize the expected utility, at a fraction of the cost of the optimal decoder. Remarkably, we find that the first stage alone$\unicode{x2014}$which makes the matching aware of the gauge choice at no cost beyond bare MWPM$\unicode{x2014}$already performs near-optimally up to the largest sizes we study, $N=256\times256$, closing up to $87\%$ of the gap between the bare-MWPM and optimal decoding thresholds. Generalizing MWPM and MLD, the maximum-utility decoder (MUD) establishes a versatile framework that can be explicitly tailored to the operational demands of specific experiments by redefining the utility function.
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High Energy Physics (Theory)
The Lorentzian Geometry of Tunneling in Global de Sitter at Late Time
Thibaut Coudarchet, Ben Freivogel, Bjoern Hassfeld et al. (+1 more)
It is widely believed that Coleman–De Luccia (CDL) instantons characterize tunneling transitions in a de Sitter multiverse. Their most naive interpretation uses analytic continuation to Lorentzian de Sitter at the minimal size of the spatial three-sphere. However, what one really wants is a geometry where a small bubble of new
vacuum forms within the huge spatial sphere of an old parent de Sitter. Even by applying de Sitter isometries to the original CDL solutions, this cannot in general be achieved. In particular, it fails in the
gravity-dominated regime, i.e. for up-tunneling and for transitions with heavy domain walls. These cases remain pathological in that the whole multiverse is in the causal future of every single up-tunneling event. To solve this problem, we develop a
Hamiltonian description of how a small off-shell bubble grows and eventually goes on shell within the large spatial sphere of late-time de Sitter. We provide the corresponding WKB analysis, recovering the CDL rate. We explain that our tunneling process and that of CDL are described by two different analytic continuations of a unique on-shell trajectory in the
Hamiltonian treatment. Our analysis has crucial implications for the Larfors–Johnson problem, which questions the standard mechanism for populating the string-theoretic flux landscape on the basis of an instability of the relevant domain walls.
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All authors Thibaut Coudarchet, Ben Freivogel, Bjoern Hassfeld, Arthur Hebecker
High Energy Physics (Phenomenology)
Extra-dimensional Origins of Chemical Potentials at the Cosmological Collider
Raman Sundrum and Zhaohui Xu
We study the realization of the chemical potential mechanism in cosmological
collider physics in a robust class of inflationary models arising from multiple higher-dimensional gauge fields. The rolling inflaton background corresponds to an electric field in the extra dimension in which charged particles are produced analogously to the Schwinger mechanism, while neutral particles can be produced through non-minimal interactions. We show that particles heavier than the inflationary Hubble scale can be created without Boltzmann suppression in both cases. In particular, charged Kaluza-Klein excitations can be created through minimal gauge interactions. We construct realistic models along these lines consistent with both theoretical and experimental constraints.
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Disordered Systems and Neural Networks
An asymptotically solvable model of many-body critical phases: mobility edges, scars, and inverted scars
Yi-Ting Tu, Zi-Jian Li and Sankar Das Sarma
While the prethermal regime of random many-body localized (MBL) systems is dominated by accidental many-body resonances, another class of resonances, originating from the underlying potential structure, is expected in large-size deterministic systems. It is known that this class of resonances can lead to single-particle critical phases that are neither localized nor extended, but the consequences in interacting systems remain unclear. In this work, we construct an asymptotically solvable model of a one-dimensional nearest-neighbor interacting
spin chain, whose spatial structure induces a hierarchy of mirror-like many-body resonances. We derive two phases in the thermodynamic limit, characterized by the satisfaction and violation of a version of the weak eigenstate thermalization hypothesis (ETH). While these two phases are similar to the usual MBL and ETH phases, there exist rare eigenstates that behave like the opposite phase, interpreted as many-body scars and inverted scars. Surprisingly, the two phases can be separated by a finite-temperature phase transition, corresponding to a thermodynamic many-body mobility edge, which was often believed to be impossible. Our results also suggest the existence of delocalized rare regions in an otherwise-localized interacting Aubry-André model, even if there are no low-disorder regions like those in random systems. This challenges the common belief that there is no avalanche instability in quasiperiodic MBL.
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Optics
A 2D Holographic Approach for All-Optical Single-Shot Temporal Characterization of SASE FEL Pulses
A. Azzolin, O. Cannelli, K.-F. Wong et al. (+31 more)
X-ray Free-electron
lasers (XFELs) deliver ultrashort and ultrabright radiation in a
photon-energy range spanning from extreme ultraviolet to hard X-rays. Supporting pulse durations down to hundreds of attoseconds, these sources are unique in enabling imaging of matter with unprecedented temporal and spatial resolution. However, schemes that produce such ultrashort pulses typically rely on Self-Amplified Spontaneous Emission (SASE), a
stochastic process that introduces significant temporal and spectral jitter, therefore requiring single-shot characterization methods for post sorting the acquired data. Although various methods have been developed for pulse characterization and delay tagging, they often come with experimental and computational complexity. Moreover, no existing method currently combines both single-shot pulse reconstruction and delay tagging at the attosecond time scale. To close this gap, we present two-dimensional time-domain Double-Blind Holography (2D-TDDBH), an entirely novel approach combining double-blind holography with concepts from diffractive imaging and ptychography. By recording the 2D spatial profile of the spectral interference between an extreme ultraviolet (XUV) FEL source and a high-harmonic generation (HHG)-based source, we achieve simultaneous waveform reconstruction and delay tagging of sub-10 fs FEL pulses with attosecond precision.
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All authors A. Azzolin, O. Cannelli, K.-F. Wong, V. J. Yallapragada, E. P. Månsson, C. Papadopoulou, E. Appi, U. Frühling, A. Magunia, M. Seitz, J. Hahne, A. bin Wahid, P. Biesterfeld, P. Mosel, S. Fröhlich, G. Cirmi, N. Kschuev, J. Roensch-Schulenburg, S. Schulz, S. Düsterer, M. Kovacev, U. Morgner, R. Moshammer, T. Lang, C. M. Heyl, V. Wanie, O. Raz, C. Ott, T. Pfeifer, E. Schneidmiller, N. Dudovich, D. Oron, A. Trabattoni, F. Calegari
Soft Condensed Matter
A Synthetically-accessible Universe of Chemically Recyclable Polymers
Anagha Savit, Wei Xiong, Harikrishna Sahu et al. (+3 more)
Polymers synthesized via ring-opening polymerization (ROP) of cyclic monomers represent an important class of materials due to their chemical recyclability and possible insertion in several critical applications. We present a
dataset of 1 million synthetically realizable ROP
polymer structures generated through a combination of Virtual Forward Synthesis (VFS) and
polymer expert
language models and qualified by stringent chemical heuristics. VFS is used to generate ROP
polymers by applying known reactions to existing monomers. The
polymer foundation models polyBART and POLYT5 further enable the generation of ROP candidates, with polyBART exploring its learned latent space and POLYT5 producing candidates via sequence-to-sequence generation. The resulting ROP
polymers are subjected to robust filtering criteria to ensure novelty, validity and overall data quality through a combination of automated validation pipelines and a comprehensive set of chemist-informed heuristic rules introduced in this work for the first time. We hope that this
dataset will serve as a valuable resource for downstream sustainable applications.
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All authors Anagha Savit, Wei Xiong, Harikrishna Sahu, Shivank S. Shukla, Will R. Gutekunst, Rampi Ramprasad
High Energy Physics (Phenomenology)
Low-lying singly heavy baryon states based on the rigorous calculation with the relativized quark model
Zhen-Yu Li, Guo-Liang Yu, Zhi-Gang Wang et al. (+1 more)
In this work, the low-lying $\mathbf{6}_{F}$ singly heavy
baryon states with positive-parity are studied in detail in the framework of the relativized
quark model by using the improved calculation scheme which has successfully explained the fine structure of the low-lying negative-parity singly heavy
baryons. The complete mass spectra of all the singly heavy
baryon families obtained in the same framework and calculation scheme are systematically analyzed. The
baryon states marked with (mass)$J^{P}$ are obtained by considering the mixing effect rigorously. It is found that the mixing effect in the singly heavy
baryons depends on the
flavor symmetry of the two light
quarks and the
baryon parity. The results show that the high-precision calculation can reproduce most of the data perfectly, and the statistical error between the calculated masses and the experimental data is only 6.96 MeV. This confirms the reliability of the improved calculation scheme. The rigorous calculation achieved by the two-step GEM enables us to analyze the detailed behavior of the various strong interaction components within the
baryons with a high-precision and discover the truth of the “soft QCD”. The large amount of data obtained in this work serves as the reliable references for related experimental and theoretical researches.
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All authors Zhen-Yu Li, Guo-Liang Yu, Zhi-Gang Wang, Jian-Zhong Gu
Quantum Physics
Annemarie Wolff, Kathleen Hamilton, Kahn Rhrissorrakrai et al. (+3 more)
Forecasting neural activity from short recordings remains a fundamental challenge. Reservoir computing may offer an efficient paradigm for temporal prediction, however classical reservoirs typically underperform in small-data regimes. Here we investigate whether
quantum reservoir computing (QRC) can help overcome this limitation. Building on recent advances, we introduce a
quantum reservoir based on a transverse-field Ising model, combined with heterogeneous
quantum measurements and
polynomial ridge regression. On a standard
benchmark task, results show that the
quantum reservoir outperforms a classical counterpart overall, with prediction accuracy strongly dependent on reservoir parameters. We further demonstrate feasibility by running the same task on
quantum hardware. To assess performance on biological signals, we evaluate QRC on simulated human electroencephalography (
EEG) data with a parallel reservoir architecture. On this challenging task, the tested
quantum reservoir did not match the performance of the classical one, but it produced stable, convergent predictions. This is a meaningful first step toward
forecasting of biologically realistic neural data using a
quantum reservoir. Overall, our findings indicate that although current
quantum hardware and parallel reservoir architectures do not yet surpass classical methods on complex neural signals, QRC can be executed on near-term devices and does converge with realistic
EEG-like data. This work establishes a practical baseline for future algorithmic and hardware developments aimed at clinical time-series
forecasting with
quantum systems.
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All authors Annemarie Wolff, Kathleen Hamilton, Kahn Rhrissorrakrai, Laxmi Parida, Filippo Utro, Guillaume Dumas
Materials Science
Vibrational spectroscopy identifies the bond asymmetry of hexagonal diamond
Li Zhu
Bulk hexagonal diamond has been synthesized by independent routes, but its structure remains contested: the two recent refinements disagree even on the sign of the difference between its two inequivalent bond lengths, 238~mÅ apart, and both depart from an earlier 2003 refinement. Here we test the competing structures with first-principles
lattice dynamics. Relaxed hexagonal diamond has an interlayer bond longer than the intralayer bonds by 24~mÅ in both functionals, an effect of its eclipsed conformation that scales with polytype hexagonality. The bright zone-center $A_{1g}$ mode gauges the interlayer bond at $\approx\!-2{,}100$~\icm~Å$^{-1}$, and neither refined coordinate reproduces the full pattern of measured modes. The only structure matching the twinned sample's three bands requires tens-of-gigapascals confining stress and
lattice constants excluded by its own diffraction. Raman spectroscopy and diffraction jointly select a small positive bond asymmetry: inverting the spectrum of the phase-pure sample gives $\OB-\OA=24\pm3$~mÅ (95% interval), and two determinations on separate samples give $+33\pm8$ and $+60\pm45$~mÅ. The 1{,}529~\icm{} feature cannot be assigned to homogeneous ideal 2H diamond, and the local HRTEM observation remains an open puzzle.
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Materials Science
Wrinkling of Randomly Heterogeneous Film-Substrate Systems
Xinyu Xing, Liyu Zhong, Feng Deng et al. (+1 more)
Wrinkling instabilities in stiff films on compliant substrates are strongly affected by spatial fluctuations in film stiffness. We develop a homogenized instability theory for one-dimensional film–substrate systems with random bending stiffness. The heterogeneous stability equation is reformulated as a Lippmann–Schwinger equation for the
curvature field, and a strong-contrast expansion is derived using a local–nonlocal kernel decomposition and a cavity-field formulation. Truncation at third order yields an effective polarizability and a Dyson-type dispersion relation for predicting the critical load and wavenumber. The stiffness is modeled as an exponentially mapped Gaussian random field, allowing the required two- and three-point connected statistics to be obtained analytically. The theory is validated against generalized
eigenvalue calculations and
Fourier spectral simulations. Increasing stiffness contrast lowers the critical load and shifts the instability toward higher wavenumbers, producing shorter wrinkles. At weak contrast, the threshold follows the universal scaling $N_c^{(0)}-N_c\sim\varepsilon^2$, whereas at moderate and strong contrast the third-order approximation is more accurate than the second-order theory. Wavelength selection is controlled by the ratio of the dominant material wavelength $\lambda^\ast$ to the harmonic-mean reference wavelength $\lambda_H$. For $\lambda^\ast/\lambda_H<1$, the harmonic-mean model accurately predicts the wrinkle wavelength. The framework provides a mechanics-based tool for reliability assessment and design of statistically heterogeneous film–substrate systems.
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All authors Xinyu Xing, Liyu Zhong, Feng Deng, Sheng Mao
Instrumentation and Methods for Astrophysics
The critical role of HST UV spectroscopy in constraining red supergiant binary systems
Daniel Jadlovský, Andreas Sander, Lee Patrick et al. (+3 more)
The Hubble Space
Telescope (HST) has advanced our knowledge of
stellar evolution thanks to its unique high-spectral resolution and high-sensitivity capabilities in the UV region, especially for hot massive
stars. Within the field of red supergiants (RSGs), it has led to several major insights as well, such as, for example, characterizing the embedded hot companion in the VV Cephei system, the detection of surface mass ejection from Betelgeuse, and unveiling the rich population of RSG+B binaries in the Magellanic Clouds. We demonstrate that nowadays (and in the decade to come) we need HST more than ever, as for the first time, thanks to the significant advances of high-angular-resolution interferometric and astrometric techniques, we can resolve the orbital motion of
stellar components in RSG systems. However, the long wavelengths are dominated by the cool RSGs. Thus, observing such companions in the UV with HST is the only way to constrain the properties and velocity of the hot companions, adding the required missing piece of information for constraining the orbital solution and evolutionary status of RSG systems. Such observations are critical for understanding the interaction and mass transfer in massive binary systems and their connection to the observed population of
supernovae.
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All authors Daniel Jadlovský, Andreas Sander, Lee Patrick, Jiří Krtička, Gemma González-Torà, Matheus Bernini-Peron
Quantum Physics
Exact minimum measurement dependence for faithful local deterministic models of multipartite GHZ-Mermin correlations
Aaron Alai
A local deterministic model can reproduce Bell-inequality violations only if the hidden state depends on the measurement settings.
Hall found the minimum such dependence for the singlet state [Phys. Rev. Lett. 105, 250404 (2010)] and posed the corresponding problem for the Mermin state [Phys. Rev. A 84, 022102 (2011)]. This paper solves it, for the $n$-party GHZ-Mermin scenario at every $n \geq 3$, with the marginals reproduced as well as the correlators. The minimum measurement-dependence fraction is $F_{\min}(n) = R/[2(R+1)]$, with $R = 2^{\lfloor (n-1)/2 \rfloor}$ the Mermin violation ratio: $1/3, 2/5, 4/9, 8/17, \ldots$, always below $1/2$. The lower bound follows from Mermin's inequality by a general overlap bound; the upper bound is an explicit model, uniform on the hidden-variable classes that violate the fewest constraints, with closed-form counts; a reduction
theorem shows that for Mermin scenarios the marginals impose no additional dependence. The Mermin values are also certified by integer-arithmetic enumeration through $n = 22$. The formula was stated as a
conjecture in the first version of this paper and was first proved, by a different route, by Wang, Yao and Chen; the proof here was obtained independently and the two agree. Every minimal contradiction of size $k$ among stabilizer constraints has correlator-only minimum $1/(k-1)$. With the marginals included the minimum is the same on every core of the $C_5$ ring cluster, on the size-4 and size-5 cores of $C_4$ and on every four-core of $C_6$, but larger on the size-6 and size-7 cores of $C_4$ and on 112 of the 1,920 five-cores of $C_6$, with exact certificates on both sides in every case.
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General Relativity and Quantum Cosmology
Self-Forces as Nonlocal Probes of Gravastar Interiors
Bokai Zhang and Yungui Gong
Compact objects with the same exterior metric are locally indistinguishable to test particles, yet observables built from retarded fields can retain information about the spacetime outside the particle's immediate neighbourhood. The self-force acting on a particle in curved spacetime provides a unique probe of both the local geometry and the global structure of the background spacetime. We calculate the static, conservative self-force on minimally coupled scalar and electric charges in the simplest thin-shell gravastar: a de Sitter core matched to a Schwarzschild exterior. Weak-field expansions in the compactness $M/R$ are obtained analytically and summed in closed form. For a scalar charge outside the gravastar the self-force is nonzero—in contrast to the exactly vanishing result for a Schwarzschild black hole of the same mass—and behaves as $\tfrac{2}{5}q^2 M R^2/r_0^5$ at large distances, while for an electric charge the universal Smith–Will force $e^2M/r_0^3$ is corrected by a structure-dependent term $\tfrac{4}{5}e^2 M R^2/r_0^5$. Inside the gravastar the scalar self-force is directed toward the center at leading order in $M/R$, vanishes linearly at the center, and produces harmonic oscillations of the charge about the center; the electromagnetic self-force inside the gravastar behaves similarly. The results demonstrate explicitly that the self-force depends not only on the local
curvature surrounding the particle but also on the global structure of spacetime: although the exterior geometry of a gravastar is identical to that of a Schwarzschild black hole, the interior boundary conditions modify the regular field and therefore produce distinct self-forces.
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High Energy Physics (Phenomenology)
Testing Lepton Wave Function Factorization in $^{71}\text{Ge}$ Electron Capture
M. Cadeddu, N. Cargioli, M. Cau et al. (+2 more)
Electron-capture ratios provide precision tests of atomic wave functions and of possible non-factorization effects in
nuclear electron capture. By exploiting exact leptonic wave functions, we present a general framework for predicting the electron capture rates of $^{71}\mathrm{Ge}$. Adopting a non-factorized treatment of the transition
matrix element, we investigate the interplay between the
nuclear transition density, which encodes the
nuclear structure contribution, and the leptonic wave functions. Using phenomenologically constrained transition densities, we quantify the impact of non-factorization effects on the capture rates. Finally, we compare our theoretical predictions for the $L/K$, $M/K$ and $M/L$ electron capture ratios with the current experimental world averages, providing an up-to-date assessment of the theoretical and experimental status of $^{71}\mathrm{Ge}$ electron capture.
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All authors M. Cadeddu, N. Cargioli, M. Cau, F. Dordei, L. Ferro
Mathematical Physics · Cross-listed from math.CO
A bijective topological recursion for maps
Gaëtan Borot, Alessandro Giacchetto and Lasse Merkens
We prove bijectively a recursive excision formula for maps of arbitrary
topology. This yields the topological recursion formulae governing their enumeration, already at the level of formal generating series and without any analyticity assumption. We extend the result to maps carrying self-avoiding loop models and to stuffed maps, i.e. a variant of maps allowing faces of arbitrary
topology. Our results give a precise combinatorial meaning to all terms of the (blobbed) topological recursion known for (stuffed) maps, including the recursion kernel, which had so far been missing. The construction relies on the simple idea of iterating Tutte's
algorithm until the
topology changes. Equivalently, it can be interpreted as a pair-of-pants decomposition driven by a path issuing from the root of the first boundary, providing an analogue for maps of the Mirzakhani-McShane identity for
hyperbolic surfaces.
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Materials Science
AC Field-driven orientational crossover and energy dissipation in suspended magnetic nanoparticles
Iago López-Vázquez, Siraj Ul Haq, Kazuya Okada et al. (+4 more)
By combining the Landau–Lifshitz–Gilbert equation with Brownian rotational dynamics of
magnetic nanoparticles (MNPs), we theoretically investigate the role of particle rotation through easy-axis reorientation in
magnetic fluid hyperthermia (MFH). Our results reveal a field-driven crossover in the stationary orientation of the easy axes, from predominantly perpendicular to predominantly parallel or antiparallel to the applied field as the field amplitude increases. Although the precise crossover field depends on particle size and excitation frequency, it occurs at approximately $0.5H_k$, where $H_k$ is the uniaxial anisotropy field. These orientational regimes are directly linked to the underlying microscopic dynamics and the associated MFH performance through the occurrence of switching and non-switching hysteresis cycles, predominantly associated with Néel magnetization reversal and Brownian particle rotation, respectively. The relative importance of these dissipation mechanisms also depends on frequency: at $f=1$ MHz, Brownian heating dominates at low field amplitudes, whereas Néel heating dominates at high fields. By contrast, at $f=100$ kHz, both contributions remain comparable over most of the investigated field range.
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All authors Iago López-Vázquez, Siraj Ul Haq, Kazuya Okada, Sergiu Ruta, Roy W. Chantrell, Òscar Iglesias, David Serantes
Materials Science
Centimeter-scale fully suspended metal and metal oxide thin films by one-step transfer-free liquid metal capillary forming
Chunlei Song, Zhenqi Guo, Yuanting Su et al. (+4 more)
Fully suspended thin films can decouple substrate effects and provide additional tuning degrees of freedom compared with their substrate-supported counterparts, making them unique platforms for next-generation thin film devices. Here we report one-step, transfer-free and substrate-free fabrication of centimeter-scale ultrathin fully suspended metal and metal
oxide film structures via
liquid metal capillary forming. We show that, analogous to soap film formation, the instantaneously developed few-nanometer-thick native surface
oxide can laminate various
liquid metals into micrometer-thick metallic films. Surprisingly, the surfactant-like metal
oxide bilayer can survive dewetting-induced
liquid metal drainage, forming suspended two-dimensional films featuring an enormous lateral size-to-thickness ratio on the order of 10^7. We further demonstrate rapid prototyping of metallic minimal-surface thin-walled structures and ultra-sensitive acoustic wave detection with these suspended thin film platforms.
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All authors Chunlei Song, Zhenqi Guo, Yuanting Su, Changren Tian, Yeqi Zhu, Liang Lei, Jianbo Tang
Quantum Physics
Canonical quantization of the Pais-Uhlenbeck oscillator with a higher-derivative perturbation: a covariant phase space approach
Jie-qiang Wu and Jinan Zhao
In this paper, we apply the covariant phase space formalism to the perturbative canonical quantization of the Pais-Uhlenbeck oscillator, with the acceleration-squared term treated as a perturbation. We quantize this model by constructing the
symplectic form on the low-energy solution space. We then compute the energy spectrum and the unequal-time commutator in a perturbative way, and obtain the results that agree with the expansion of the exact low-energy theory. The perturbation method bypasses the standard Ostrogradsky construction and naturally decouples the Ostrogradsky ghost. This work extends our previous perturbative quantization scheme to genuine higher-derivative theories.
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