Astrophysics of Galaxies
MUSE-ALMA Haloes XV: Cold molecular, ionised, and stellar kinematics of HI-rich galaxies at z $\sim$ 0.5
C. Barfety, N. M. Förster Schreiber, C. Péroux et al. (+13 more)
Spatially resolved
galaxy kinematics are well studied at z $\sim$ 0 and z > 1, revealing that disks are common out to z $\sim3-6$, albeit with higher velocity dispersions. z $\sim$ 0.5 marks a key transition in the drivers of disk
turbulence and baryonic-dark matter mass budgets, yet multi-tracer resolved kinematic studies remain rare beyond the local Universe. We exploit a unique
dataset combining ALMA CO observations with MUSE ionised gas and
stellar continuum data to study the resolved kinematics of six
galaxies at 0.43 < z < 0.83, part of the MUSE-ALMA
Haloes program, selected via their association with H I absorption systems and spanning
stellar masses from log$(M_\star/M_\odot) = 10.1 - 11.8$. Combining new ALMA/CO data with existing MUSE H$\beta$ kinematics and HST morphologies, we classify
galaxies using morpho-kinematic criteria. For rotating disks, we jointly model H$\beta$ and CO(2-1) kinematics with DYSMALPY and compare results to theoretical predictions for pressure support, while pPXF is used to fit
stellar absorption features. Four of the six
galaxies are classified as disks, with two having known group members. These disks show elevated gas velocity dispersions relative to z $\sim$ 0 disks, consistent with interpolated trends between z $\sim$ 0 and z > 1. The results support marginally stable gaseous disks where gravitational instability still contributes alongside
stellar feedback, with tentative evidence for a dynamically hotter warm ionised phase relative to cold gas ($\sigma_{0, H\beta} \sim 1.7 \times \sigma_{0, CO}$). We derive an average dark matter fraction $\langle f_{DM} \rangle = 0.42\pm0.14$, consistent with observations at similar
redshifts,
stellar masses, and surface densities. This work demonstrates the value of self-consistent, multi-wavelength analyses for probing disk settling physics in a relatively unexplored
redshift range.
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All authors C. Barfety, N. M. Förster Schreiber, C. Péroux, L. J. Tacconi, J. Chen, S. Weng, V. Bollo, T. O'Beirne, M. Zwaan, R. Augustin, B. Casavecchia, L. Chemin, A. L . Danhaive, N. Guerra-Varas, V. Kulkarni, R. Potlia
Astrophysics of Galaxies
MUSE-ALMA Haloes XIV: The ALMA Large Programme Data Release
Céline Péroux, Jianhang Chen, Victoria Bollo et al. (+10 more)
The interactions between gas and
galaxies are of paramount importance to our understanding of structure formation. A fundamental element of such
baryon cycle studies is a complete census of the condensed matter (
stars and cold gas) in both
galaxies and their immediate surroundings, the so-called circumgalactic medium. Of particular importance are the processes of converting molecular gas into
stars and deciphering whether this <100K gas is tracing gas flows. The MUSE-ALMA
Haloes survey has assembled probes of the neutral atomic gas HI, ionised gas and
stellar component for a sample of 79 $z\sim0.5$
galaxies. This is achieved by combining absorption line spectroscopy of background
quasars with projected impact parameter as low as 5 kpc and up to 250 kpc to probe the low density circumgalactic gas with emission line tracers of both ionised gas and
stars. This paper presents the Large Programme observational set-up and releases the data characterising the molecular phase of some of the MUSE-ALMA
Haloes targets so as to reach a complete census of their condensed
baryons. ALMA's unique millimetre coverage and high sensitivity is ideal to characterise the CO emission of these $z\sim0.5$ HI-selected
galaxies. By measuring the molecular mass, kinematics, gas flows and gas fractions, this project then: i) quantifies the role of molecular gas in HI-rich
galaxies, ii) characterises the molecular phase of gas flows from morpho-kinematics analyses, and iii) establishes a census of the condensed
baryons in the interstellar and circumgalactic media. Ultimately, these results will provide unique insights into the
baryon cycle - a crucial component of
galaxy formation.
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All authors Céline Péroux, Jianhang Chen, Victoria Bollo, Tamsyn O'Beirne, Capucine Barfety, Simon Weng, Ramona Augustin, Benedetta Casavecchia, Martin Zwaan, Linda Tacconi, Natascha Föster Schreiber, Laurent Chemin, Varsha Kulkarni
High Energy Astrophysical Phenomena
Quasi-periodic eruption spectral-timing: EMRIs crossing warped accretion disks
Joheen Chakraborty, Andrew Mummery, Eliot Quataert et al. (+3 more)
Quasi-periodic eruptions (QPEs) are repeating X-ray transients from
galactic nuclei potentially caused by a
stellar-mass orbiter repeatedly colliding with the
accretion disk of a supermassive black hole (SMBH) in an extreme mass-ratio inspiral (EMRI). In this picture, the eruption arrival times encode the orbit and its relativistic precessions, while the quiescent spectral energy distribution (SED) probes the same disk and SMBH, providing two independent constraints on the same orbit-disk system. We present a joint spectral-timing framework that takes advantage of this by simultaneously fitting an analytic QPE timing model built on Kerr geodesic frequencies and a warped disk geometry, coupled to a self-irradiated disk SED model sharing the same SMBH mass,
spin, and disk parameters. We apply it to the QPE sources GSN 069 and eRO-QPE2, showing that the QPE timings and quiescent spectra can be reproduced simultaneously in each, providing circumstantial support for the EMRI model and warped disks in these systems. However, given the sparse timing data in both sources, neither admits a unique solution. In eRO-QPE2, we identify six physical modes which reproduce the timings and SED comparably well, motivating denser observing campaigns to identify one unambiguously. Our results demonstrate both the promise of QPE spectral-timing as a precision probe of SMBHs, their
accretion disks, and orbiting companions, and the aliasing subtleties of sparsely sampled QPE timings.
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All authors Joheen Chakraborty, Andrew Mummery, Eliot Quataert, Riccardo Arcodia, Itai Linial, Erin Kara
Mesoscale and Nanoscale Physics
Gentle Floquet control of orbital Hall effect and orbital inverse Faraday effect
Pei-Han Lin, Roderich Moessner and Egor I. Kiselev
Floquet engineering controls material responses via a time-periodic electromagnetic drive. An important task in practice is to reduce the driving strengths required to implement Floquet protocols. We show that in systems with strong phase-space constraints, where the response is dominated by a small region of momentum space, the relative impact of a resonant Floquet drive is enhanced. We demonstrate this idea on the example of the orbital
Hall effect, where
equilibrium occupations restrict the interband coherence to a narrow momentum interval $\hbar\Delta k$. The ratio $eE_0/(\Omega_0\hbar\Delta k)$, where $\Omega_0$ is the frequency of the drive, is considerable even at modest field amplitudes $E_0$, leading to a large relative change in the orbital
Hall conductivity. Due to the non-trivial orbital texture, the circularly polarized drive induces an inverse orbital Faraday effect by magnetizing the electrons. We show that the corresponding susceptibility is controlled by the interband
quantum metric that determines the resonant Floquet hybridization.
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High Energy Physics (Phenomenology)
Short-Range Correlation Scaling of Nuclear Parton Modifications: Consistency Tests and Recoil-Tagged Charm-Production DIS
Yong Zheng, Shu-Man Hu, Wei Wang et al. (+2 more)
We investigate short-range correlation (SRC) scaling of
nuclear gluon modifications using nCTEQ SRC abundances and EPPS21
gluon distributions. Rescaling the EPPS21 central modifications by these abundances yields an approximately common curve for six
nuclei from carbon to lead over $0.1\leq x\leq0.4$ at $Q^2=10$ and $100\,\mathrm{GeV}^2$. The SRC interpretation is supported by the broad agreement between the fitted abundances and high-momentum
proton fractions from variational Monte Carlo calculations. Using an SRC
proton fraction of approximately $20\%$ in carbon, the measured EMC-SRC correlation also gives a pure-SRC EMC slope of $1.94\pm0.12$, consistent with the nCTEQ estimate $2.02\pm0.20$. To test the connection between this scaling and SRC configurations, we propose
recoil-tagged charm-production in deuteron deep-inelastic scattering (DIS), combining a backward high-momentum
proton tag with a
gluon-sensitive hard process. We formulate leading-power collinear factorization through an extended fracture function, which reduces within the plane-wave impulse approximation to a deuteron light-front spectral factor times a
recoil-conditioned
neutron gluon distribution. The tagged charm reduced cross section and its ratio to inclusive tagged DIS provide complementary observables for comparing
gluon modifications in SRC-enriched configurations with the scaling inferred from inclusive nPDFs.
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All authors Yong Zheng, Shu-Man Hu, Wei Wang, Ji Xu, Shuai Zhao
Fluid Dynamics · Cross-listed from cs.ET
Analytical Modeling of Open- and Closed-Loop Dispersive Molecular Communication Channels with Pulsatile Flow
Theofilos Symeonidis, Fardad Vakilipoor, Timo Jakumeit et al. (+3 more)
Molecular communication (MC) is a communication paradigm in which information is conveyed through the release, propagation, and reception of molecules. Many envisioned healthcare applications of MC are expected to operate inside the human body, where the cardiovascular system (CVS) may serve as the physical propagation environment and molecular transport is governed by
diffusion and blood flow. Although blood flow is inherently pulsatile, most analytical MC channel models assume steady flow. In this paper, we develop a time-variant analytical model for dispersive MC channels with pulsatile flow. We derive the straight-duct response as a Normal distribution with time-variant mean and variance, capturing the combined effects of
diffusion and pulsatile flow, and extend it to closed-loop channels through a wrapped-Normal representation. The model is validated against three-dimensional (3D) particle-based simulations (PBSs) for synthetic and physiologically motivated velocity waveforms. We further derive a closed-form first-order approximation for the first-arrival peak time and introduce the nondimensional indicator $S_{\mathrm{Rx}}$ for assessing the applicability of the reduced one-dimensional (1D) model. Our results show that pulsatility has the strongest influence when molecular transport is predominantly advective and the temporal flow variations are not averaged out, whereas stronger
diffusion and faster pulsations reduce its impact on the received signal. Moreover, a PBS-based parameter sweep supports $S_{\mathrm{Rx}} \ge 2$ as a practical criterion for the applicability of the proposed analytical model. Finally, relating the analytical assumptions to representative blood-vessel classes shows that model applicability depends not only on the transport conditions but also on physiological properties such as vessel
rigidity,
geometric uniformity, and blood rheology.
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All authors Theofilos Symeonidis, Fardad Vakilipoor, Timo Jakumeit, Robert Schober, Nunzio Tuccitto, Maximilian Schäfer
Soft Condensed Matter
Self-organization in Chiral Gliding Filaments
Josue Yaedalm Son, Hyejeong Kim and Vahid Nasirimarekan
Filamentous cyanobacteria form extensive kilometer-scale mats in aquatic environments, yet the physical mechanisms driving their macroscopic self-organization remain elusive. Here, we investigate the dynamics of filamentous cyanobacterial assemblies within a quasi-two-dimensional confinement. Our observations reveal that
chiral gliding drives active tangling between individual filaments, inducing rapid network contraction and the formation of densely packed aggregates. By quantifying single-contact forces, we demonstrate that these mechanical interactions generate significant contractile stresses. Together, our findings sug- gest that
chiral gliding has evolved as a physical mechanism to maximize inter-filament interactions and drive large-scale collective organization.
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Statistical Mechanics
Percolation on interdependent one-dimensional long-range networks
Adar Sharabi, Amir Bashan, Sergey V. Buldyrev et al. (+1 more)
We study the emergence of a mutual
giant component in a multiplex network comprised of two one-dimensional long-range networks on a
lattice. The probability that two nodes on one
lattice, with a distance $r$ between them, are connected with an edge falls algebraically with distance as $Cr^{-(1+\sigma)}$, where $0 < \sigma < 1$ and $0 < C \leq 1$. A mutual
giant component exists if $C > C_c^{\mathrm{mul}}$, where $C_c^{\mathrm{mul}}(\sigma)$ is a critical value of $C$ that is dependent on $\sigma$. We find rigorous lower bounds on $C_c^{\mathrm{mul}}$, and a tree approximation whose estimate of $C_c^{\mathrm{mul}}$ agrees with simulations within 0.6% for $\sigma \leq 0.5$. The multiplex network is significantly less stable than the single network case, as is evident by the larger value of $C_c^{\mathrm{mul}}$, which is up to 2.4 times the single-layer value. Our simulations indicate that the order of the transition depends on $\sigma$. For $\sigma \leq 0.35$ the mutual
giant component collapses abruptly, in a first-order phase transition, while for $\sigma \geq 0.4$ the transition is continuous. When the dependency links connect random pairs of nodes, the transition is first order for all $\sigma$.
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All authors Adar Sharabi, Amir Bashan, Sergey V. Buldyrev, Guy Amit
Disordered Systems and Neural Networks
Revealing more on complex energy landscapes by passing less local information: Cavity approach with trust region in non-convex optimization problems
Zhiqi Xu and Chi Ho Yeung
Energy landscapes of non-convex optimization problems are high-dimensional surfaces that are difficult to reveal, visualize, or analyze. Message-passing
algorithms, or equivalently cavity approaches in statistical physics, may fail to identify local minima as messages do not converge owing to the ruggedness of the energy landscapes. Here we aim to reveal the characteristics of these complex energy landscapes by limiting the amount of information passed in local messages, improving the convergence of messages for local minima. By studying a routing optimization problem with its convexity governed by a single parameter, we introduce a cavity message-passing
algorithm with a trust region, and sample ensembles of converged local minima of rugged energy landscapes across many independent realizations of the same problem instances. We observe three regimes with different characteristics of the energy landscapes: (1) a maximally rugged regime with a peak in the diversity of low-energy minima; (2) an intermediate regime with a hierarchical multi-cluster organization of low-energy solutions; and (3) a smooth regime dominated by a single minimum. Additional tests show that the converged energies are largely insensitive to the size of the trust region if the size is small or moderate, demonstrating the robustness of the proposed approach in identifying characteristics of rugged energy landscapes.
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High Energy Physics (Phenomenology)
Phenomenology of axion-meson mixing and scattering processes
Noé Duarte-González
We study the mixing between a generic
axion-like particle (ALP) and the light pseudoscalar
mesons within
chiral perturbation theory ($\chi$PT), and its consequences for low-energy scattering and decay processes. Starting from the most general ALP effective Lagrangian, we derive the ALP-
meson kinetic and mass mixing induced at leading order in the ALP decay constant and isospin breaking for arbitrary ALP masses. As a result, we obtain the physical ALP mass to $\mathcal{O}(F^2/f_a^2)$, recovering the QCD-
axion limit and finding that any ALP with a vanishing bare mass shares the QCD-
axion mass. We provide a compact parameterization of every four-body amplitude involving pseudoscalar
mesons and an arbitrary number of ALPs. As an illustration, we show the $K\bar{K}\to P^0a$ scattering. The framework applies for general ALP masses and couplings and consistently incorporates isospin breaking, essential for otherwise forbidden processes.
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Mathematical Physics · Cross-listed from math.PR
Two dimensional Villain model in the BKT phase
Jiwoon Park and Wei Wu
We establish sharp two-point function asymptotics for the two dimensional Villain model at sufficiently low temperatures, confirming a central prediction in the Berezinskii-Kosterlitz-Thouless theory. We characterise the power law exponent through the renormalisation group flow of a marginal line defect observable in the dual high-temperature Discrete Gaussian model.
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Atomic Physics
A scanning cavity for large area coherent coupling in atom interferometry
D. O. Sabulsky, Q. Beaufils, A. Bertoldi et al. (+3 more)
Optical cavities can enhance atom-light coupling in atom interferometry, but free-fall geometries require large transverse modes. Marginally stable resonators provide such modes, yet aberrations and
alignment imperfections turn their near-degenerate response into detuning-dependent transverse ring modes, strongly limiting the usable interaction volume under static excitation. Here, we turn this limitation into a resource. By chirping the interrogation frequency across the cavity resonance while dynamically shaping the input amplitude, we map
laser detuning onto the transverse position and scan the cavity-enhanced coupling across the atomic cloud. In a cavity-enhanced Bragg diffraction experiment with $^{87}$Rb atoms, this produces a nearly uniform effective interaction region of about 15 mm and increases the transfer efficiency from about 5% to 28%. We also demonstrate phase-coherent operation of a three-pulse atom interferometer using chirped cavity-enhanced Bragg pulses. These results establish scanning-cavity interrogation as a route to large-area, cavity-enhanced atom interferometry.
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All authors D. O. Sabulsky, Q. Beaufils, A. Bertoldi, A. Landragin, P. Bouyer, B. Canuel
Geophysics
Quantification of plastic deformation in anorthite using micropillar compression
Sarah Incel, Chunhua Tian, Anja Schreiber et al. (+2 more)
Plagioclase is the most abundant mineral group of the crust and will therefore either control or strongly influence crustal rheology. Yet, we still know little about
crystal plasticity in plagioclase as brittle deformation dominates under most laboratory conditions. To overcome past challenges in quantifying
crystal plastic deformation in plagioclase, we used micropillar compression to quantify the strength of specific slip systems as well as the stresses necessary for mechanical twinning in anorthite. Pillars with diameters of around 1 micrometre were milled from three differently oriented cuts of the same anorthite single
crystals using focused-ion beam. Uniaxial deformation of 36 pillars in total was then conducted inside a scanning-electron microscope under either 25, 300, or 800 degrees Celsius. Most pillars were deformed with a constant displacement rate that corresponds to a strain rate of around 0.001 1/s on the pillars. We find that the critical resolved shear stress (CRSS) for mechanical (pericline) twinning lies at around 300 MPa and is, as expected from previous studies on other materials, insensitive to changes in temperature or strain rate. Pillar deformation in
crystals oriented to activate slip exhibit a strong decrease in yield stress with increasing temperature. Among the deformation mechanisms active during pillar deformation, twinning is the easiest under the applied conditions, followed by slip on (011)[100] regardless of temperature. Slip on (011)[0-11] or (0-11)[011] is consistently the hardest mechanism to activate in our anorthite pillars.
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All authors Sarah Incel, Chunhua Tian, Anja Schreiber, Vladimir Roddatis, Sandra Korte-Kerzel
Quantum Physics
Tradeoff between Wigner negativity and decoherence time for cubic Gaussian states
Matthieu Arnhem, Valerio Crescimanna, Giuseppe Patera et al. (+1 more)
Wigner negativity has been shown to be a resource in
quantum computing, raising the question of how to efficiently produce states with a large Wigner negativity. Cubic Gaussian states, obtained when a cubic gate is applied to a Gaussian state, have been proposed as candidates for this purpose. We show that cubic Gaussian states with a large Wigner negativity $\mathcal N$ necessarily have a short decoherence time $\tau$ that is bounded above by $\mathcal N^{-2}$. In other words, a large Wigner negativity comes at a cost: the decoherence time $\tau$ of cubic Gaussian states decreases at least quadratically in the negativity $\mathcal N$. Maximizing $\tau$ at fixed Wigner negativity $\mathcal N$, we show that this upper bound is reached by optimal cubic Gaussian states. They have the property that for large negativity, the optimal squeezing scales as $\ln\mathcal N$ and the optimal cubicity as $\mathcal N^{-1}$. Optimal cubic Gaussian states with large negativity can therefore be constructed with small cubicity, provided sufficient squeezing is applied. However, their decoherence time decreases with growing negativity. In addition, we show that their preparation is extremely sensitive to thermal noise. Finally, we compare, for each integer $n$, the optimal cubic Gaussian state with the $n$th Fock state that has the same negativity: despite their pronounced differences in
photon number distribution and Wigner function, we show that they have similar, be it slightly larger, decoherence times and
entanglement generating potential through a beam splitter.
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All authors Matthieu Arnhem, Valerio Crescimanna, Giuseppe Patera, Stephan De Bièvre
Solar and Stellar Astrophysics
Wave-Growth-Limited Particle Confinement in a Near-Parallel Interplanetary Shock Observed by Parker Solar Probe
A. Kouloumvakos, I. C. Jebaraj, M. A. Malkov et al. (+11 more)
Collisionless shocks confine the particles they accelerate with the upstream wave field they themselves drive. Streaming particles resonantly amplify Alfvén waves, and the waves then confine the same particles by pitch-angle scattering. The
rigidity a shock precursor can hold is therefore capped by how fast those waves grow, and that coupling has not previously been constrained in-situ at any interplanetary shock. Here we report Parker
Solar Probe measurements of a fast, near-parallel coronal mass ejection-driven shock at 0.24~AU on 2023 March 13 that constrain this wave-particle coupling through the energetic-particle population it accelerates. We measure the spectral folding energy, the boundary between the confined and the upstream-escaping
protons, and find that it falls from $\sim$6 to $\sim$1.5~MeV as $E_\mathrm{fold}\propto\Delta t^{\,\alpha}$ with $\alpha\simeq0.34$, where $\Delta t$ is the time remaining before shock arrival. One precursor convective time before arrival this boundary is at $E_\mathrm{c}\simeq 2.46$~MeV, a characteristic confinement energy of a precursor of scale $L_\mathrm{EP}$. Read through the quasi-linear marginal-stability condition, the same
evolution implies a resonant wave-growth timescale $\tau_\mathrm{growth}(E)\propto E^{1/\alpha}\simeq E^{2.92}$ that exceeds the precursor convective time above $E_\mathrm{c}$. The post-shock pitch-angle anisotropy reverses sign across the same confinement–escape transition at 2–5~MeV. The
rigidity to which a shock precursor can confine particles is therefore set, in-situ, by how quickly the streaming population builds its own confining waves.
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All authors A. Kouloumvakos, I. C. Jebaraj, M. A. Malkov, G. D. Berland, M. Gedalin, N. Wijsen, C. M. S. Cohen, O. V. Agapitov, D. J. McComas, D. G. Mitchell, E. Husidic, S. Yadav, M. E. Hill, R. McNutt
Materials Science
Universal orbital-coupling rules for hydrogen-defect interactions in bcc metals
Qianxi Zhu, Hao-Xuan Huang, Zichen Zhang et al. (+2 more)
Hydrogen-defect interactions control the performance of body-centered-cubic (bcc) metals. However, the complex variations among defects lead to various empirical models that lack transferability across defects. Here, we propose an orbital-coupling model, built on coordination number and interatomic distance, that quantifies the H solution energetics across nanovoids, vacancy loops and grain boundaries in bcc metals, and even predicts the potential-energy surfaces of H at nanovoids. Our model reveals an unconventional s-d coupling rule in the confined environment of defects: H-metal interactions exhibit a unique coordination-dependent law, whereas H-H interactions, deviating from the usually speculated s-s coupling, acquire the distance-decay law of H-metal coupling. This unusual rule proves essential to reproduce the experimentally observed bimodal profile of H desorption. Our electronic-structure-origin, unified model is thus crucial to understanding the nature of chemical bonds under constraint and engineering the H-tolerant materials.
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All authors Qianxi Zhu, Hao-Xuan Huang, Zichen Zhang, Hong-Bo Zhou, Wang Gao
Mesoscale and Nanoscale Physics
Charge transport in two-dimensional conductors with hybrid three-component plasma
A. D. Levin, V. A. Chitta, Z. D. Kvon et al. (+2 more)
Electron–hole
plasma in two-dimensional systems has mainly been studied in two limiting cases: degenerate semimetals with
parabolic bands and nondegenerate symmetric Dirac systems such as
graphene. Here we investigate a different regime realized in a gapless HgTe
quantum well: a multicomponent
plasma where massless Dirac carriers coexist with thermally activated heavy holes from lateral valence-band valleys. Near charge neutrality, the resistance increases approximately as $T^2$, in sharp contrast to the nearly temperature-independent resistivity expected for a symmetric Dirac
plasma. We show that once heavy holes are populated, charge neutrality pins the chemical potential above the Dirac point, leaving the Dirac electrons moderately degenerate while the heavy holes remain nondegenerate and obey Boltzmann statistics. The light electrons therefore scatter almost elastically from the heavy holes, allowing a relaxation-time treatment of interparticle transport. Using carrier densities from self-consistent band-structure calculations, we reproduce the data with a short-range electron–hole interaction in the weakly disordered limit, for which the conductivity scales as $T^{-2}$ and the excess resistivity is proportional to the heavy-hole density. In contrast, an unscreened Coulomb interaction would give a temperature-independent conductivity. The extracted interaction amplitude is of the expected Coulomb scale. These results establish near-critical HgTe
quantum wells as a platform for interaction-driven transport in multicomponent systems combining degenerate massless and nondegenerate massive carriers.
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All authors A. D. Levin, V. A. Chitta, Z. D. Kvon, N. N. Mikhailov, G. M. Gusev
High Energy Physics (Theory)
A toy model for the quark pole mass
Marcos Marino and Maximilian Schwick
We study the pole mass for a heavy
quark probe in the Gross–Neveu model, at the first non-trivial order in the $1/N$ expansion. We show that this mass suffers from a perturbative renormalon ambiguity structurally similar to the one in QCD. The exact large $N$ solution leads however to an explicit expression for the pole mass which can be decoded as a trans-series, and we find that non-perturbative corrections cure the renormalon ambiguity. We also calculate the self-energy of the heavy
quark beyond perturbation theory by using the OPE method with condensates, and show that the results are in agreement with the large $N$ solution. The non-perturbative corrections to the pole mass turn out to be determined to a large extent by the condensate corrections to the self-energy. However, there is a class of corrections that has to be reorganized due to on-shell effects and cannot be obtained from the conventional condensate expansion. We discuss possible implications of this toy model for QCD.
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Atomic Physics
A solid-state nuclear clock based on VUV absorption spectroscopy of $^{229}$Th
Pengfei Wang, Xu-Fei Yin, Hanlin Wang et al. (+21 more)
We demonstrate sustained operation of a solid-state thorium-229
nuclear clock using continuous-wave absorption at 148.4 nm. In a $^{229}\mathrm{Th}:\mathrm{CaF}_2$
crystal, we resolve four quadrupole components of the D center and a broader O-center resonance. Feedback on the strongest narrow component is updated approximately every 10 s and remains active throughout a 30-h record. A hydrogen-maser-referenced frequency comb measures the output. Its fractional frequency instability follows approximately $1.29\times10^{-11}(\tau/\mathrm{s})^{-1/2}$ and reaches $1.24\times10^{-13}$ at $10^4$ s. A separate 6.6-h run demonstrates feedback on a second quadrupole component. These measurements connect the resolved absorption spectra with sustained
nuclear-clock operation and frequency comparisons between
crystal segments.
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All authors Pengfei Wang, Xu-Fei Yin, Hanlin Wang, Jinming Liu, Qichen Qin, Zhouzhi Tan, Chengrun Leng, Mingxuan Zhang, Zixuan Li, Wenxin Bu, Xuan Fan, Yihang Liu, Kjeld Beeks, Benedikt Gerstenecker, Sebastian Lahs, Meng Wang, Tung-Hsun Chung, Yong-Heng Huo, Yin Hang, Hanning Dai, Thorsten Schumm, Zhiqiang Zhang, Jian-Wei Pan, Yu-Ao Chen
Statistical Mechanics · Cross-listed from q-fin.TR
On Bonart's interpretation of the Square-Root Impact Law
J.-P. Bouchaud, I. Mastromatteo and B. Toth
The square-root impact law (SRIL), $I = Y\sigma\sqrt{Q/V}$, bundles two facts that a single mechanism must explain at once: a shape (impact proportional to square-root of traded volume $Q$) and an amplitude ($Y=O(1)$, independent of the participation rate $\varphi$). Bonart has recently proposed an elegant solution: if realized and counterfactual prices are both diffusive, information-neutral impact must have white increments and the SRIL follows without the wart. We reformulate and simplify his argument, and foreground the ingredient he himself regards as essential — that the
market whitens the stationary stream of each participant's metaorders, not any isolated one. The Lillo–Mike–Farmer model satisfies his premises, yet gives an isolated metaorder the super-square-root impact $\varphi^{(1-\gamma)/2}Q^{(1+\gamma)/2}$, $\gamma\in(0,1)$, because single metaorders (i.e. not part of a stream) are statistically invisible and thus priced mechanically. We then construct an explicit multi-
agent propagator that realizes Bonart's whitening, and show it reproduces the clean SRIL precisely when the
market can attribute trades to their issuer. But correct re-attribution of anonymous trades is a formidable task, which requires
markets to behave as implausibly efficient signal processing machines. The stream hypothesis makes a sharp, falsifiable prediction — isolated metaorders, well separated in time, should not obey the SRIL — that does not seem agree with empirical data known to us. Independently, a volume-conservation argument singles out the square-root law and lays bare the step the diffusivity route must assume: diffusivity fixes the variance of impact — an additive, stationary, age-blind quantity — whereas the SRIL is a law for the mean impact, which marginally decays as $1/\sqrt{\text{age}}$ and therefore demands an origin of time.
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General Relativity and Quantum Cosmology · Cross-listed from math.DG
Almost-splitting of spacetimes under timelike sectional curvature bounds
Nicola Gigli, Melanie Graf, Robert J. McCann et al. (+3 more)
We establish an almost-splitting
theorem for spacetimes under timelike sectional
curvature bounds in the spirit of the celebrated Riemannian result due to Cheeger and Colding. More concretely, we show that if a globally
hyperbolic spacetime with timelike sectional
curvature bounded below by a nonpositive constant close to zero contains a long maximizing timelike segment, then causal diamonds along that segment are close in the Lorentzian Gromov–Hausdorff sense of Minguzzi–Suhr to those in a product metric spacetime. Our result can be interpreted as a quantitative analogue of the Lorentzian splitting
theorem for spacetimes with nonnegative timelike sectional
curvature by Beem–Ehrlich–Markvorsen–Galloway.
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All authors Nicola Gigli, Melanie Graf, Robert J. McCann, Argam Ohanyan, Eric Woolgar, Matteo Zanardini
Mesoscale and Nanoscale Physics
Coupled quantum critical states in a circuit simulator
D. B. Karki and Andrew K. Mitchell
Hybrid metal-
semiconductor quantum circuits offer a controlled setting for realizing and probing strongly correlated
quantum matter. A largely open question that may be addressed by such simulators is whether coupled critical states can combine into new non-
Fermi liquid (NFL) phases. Inspired by the recent realization of a two-site charge-Kondo
circuit [W. Pouse et al., \href{https://www.nature.com/articles/s41567-022-01905-4}{Nat. Phys. 19, 492 (2023)}], we uncover the fate of coupled Kondo anyons emerging from the two-channel-Kondo critical point at each site. Bosonization and
quantum Brownian motion methods yield the full quasiballistic phase diagram and low-temperature transport properties, while numerical renormalization group calculations resolve the complementary weak-coupling limit. Together, these provide a unified description, and reveal robust NFL phases with continuously tunable transport and susceptibility exponents. Stronger inter-site coupling ultimately produces a screened
Fermi liquid.
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High Energy Physics (Theory)
The Komar charges of type II supergravity and supersymmetric localization
Gabriele Barbagallo and Tomás Ortín
We compute the on-shell closed, generalized Komar charges associated to an arbitrary Killing vector of the two 10-dimensional $\mathcal{N}=2$ supergravity theories which are the low-energy effective field theories of the type~IIA and IIB superstrings. We study different rewritings of this charge in terms of Page charges and forms with special properties that are used in the derivation of thermodynamical relations in black $p$-brane spacetimes. The, we show that, when the Killing vector is the supersymmetric Killing vector built as a bilinear of a Killing spinor, the momentum maps of the different fields of the theory are
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Quantum Physics
Can we make sense out of negative kinetic energy?
Alessio Maiezza and Fabrizio Nesti
Many
Quantum Field Theory models, either designed to improve the ultraviolet behavior via higher derivative terms or aimed at providing unified descriptions of
Gravity, inevitably introduce negative-energy 'ghosts' states. These states raise fundamental questions regarding the stability of the theory. In this study, we investigate the time
evolution of simplified
quantum mechanical models consisting of two coupled normal and ghost subsystems. Although the full spectrum of these models is unbounded from below and, therefore, lacks a true ground state, we focus the time
evolution of a 'would-be ground state': a zero-energy eigenstate of the decoupled system. By analyzing its metastability under interactions, we gain insights into the dynamics of ghost-like states. Contrary to the standard paradigm, our results demonstrate that, across a broad range of couplings, the would-be ground state does not decay and remains dynamically stable over long times. This provides evidence towards resolving the stability problems of
Hamiltonians that are unbounded from below. We also discuss the connections with the corresponding classical and semiclassical dynamics.
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Disordered Systems and Neural Networks · Cross-listed from cs.LG
Matching of signal, noise and hardware timescales for filtering and forecasting of correlated noise signals
Joshua Donald, Alex Gabbitas, Arthur G. T. Coveney et al. (+2 more)
Physical reservoir computing exploits the nonlinear dynamics of physical systems to process time-dependent data with greater energy efficiency than conventional machine learning approaches. However, physical reservoirs have fixed intrinsic response timescales, whereas real-world signals combine deterministic and
stochastic components across multiple timescales. Here we show, using a nanoporous niobium
oxide reservoir, synthetic noisy signals and cryptocurrency-price
volatility, that the relationship among noise correlation time, reservoir
memory and forecast horizon determines whether correlated noise is filtered or predicted. Noise varying faster than the relevant reservoir
memory and forecast horizon is averaged by the reservoir, whereas the temporal structure of slower-varying noise is sufficient for algorithmic
forecasting. We introduce the reservoir
memory horizon and
forecasting regime index to distinguish these operating regimes. These contributions demonstrate that timescale matching can guide the encoding of input time series and development of physical reservoir architectures that filter, analyse and predict
stochastic signal components across distinct temporal scales.
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All authors Joshua Donald, Alex Gabbitas, Arthur G. T. Coveney, Sergey Savel'ev, Pavel Borisov
Mathematical Physics · Cross-listed from math.NT
Spacing statistics for a point scatterer on the cubic three-torus
Christopher Lutsko
We study the new
eigenvalues of a fixed point interaction on the cubic three-
torus. Their mean-one consecutive spacings converge to a probability law independent of the interaction parameter. We characterize this law by the consecutive zeros of a random meromorphic function built from three-squares congruence densities. Its small-gap distribution has the form $s^5\Psi(\log_2(s^{-2}))+o(s^5)$, where $\Psi$ is continuous, positive, and one-periodic. The proof combines periodic mean-square approximation, a weighted
Hilbert-transform estimate, and
Fourier estimates that retain the interactions between
primes.
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Strongly Correlated Electrons
Fourth-order perturbation theory for the Frohlich polaron: Analytic structure of the weak-coupling series and the crossover to strong coupling
Sankar Das Sarma
We calculate the Rayleigh-Schrodinger perturbation series for the ground-state energy and the effective mass of the three-dimensional Frohlich polaron through fourth order in the coupling constant alpha. The third- and fourth-order coefficients of the effective mass are new. Because the Frohlich interaction is a form-bounded perturbation of an isolated nondegenerate ground state at fixed total momentum, the series has a nonzero radius of convergence, and we analyze it with the ratio and Pade methods appropriate to convergent series. The coefficients are strikingly regular and are described by a simple power-law singularity at alpha near 8.5 with an exponent near 1.4. The couplings at which successive truncations of the inverse mass vanish, the first of which is the textbook breakdown value alpha = 6, are slowly converging estimates of this radius. Pade approximants built from the weak-coupling coefficients alone agree with diagrammatic Monte Carlo results for the mass to better than one percent for alpha up to 5. Exact results on the analyticity of the ground state and on the strong-coupling asymptotics imply that the coefficients cannot keep a constant sign, although all known coefficients do, so that the apparent singularity must be a complex-conjugate pair close to the positive real axis. It marks the crossover to strong coupling: the weak-coupling series locates this crossover accurately but cannot be continued through it.
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Materials Science
Solphin: Photovoltaic efficiency analysis for bulk materials using Python
Philippa U Cox, Peter P Russell, Andrea Crovetto et al. (+3 more)
In the development of photovoltaic materials, computational simulation has become a important tool for reducing the time and cost of exploring novel materials, as well as providing insights that help drive improvements in efficiency through increasing fundamental understanding. We present Solphin, a Python package for the generation, post-processing and analysis of photovoltaic calculations from periodic solid state Density Functional Theory. We include the ability to calculate the photovoltaic Figure of Merit, detailed balance and spectroscopic limited maximum efficiency, alongside other analysis methods. Solphin has been built to improve the access, reproducibility and ease of evaluating the photovoltaic potential of a material in an efficient and user-friendly manner.
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All authors Philippa U Cox, Peter P Russell, Andrea Crovetto, Alexander G Squires, Louie Slocombe, David O Scanlon
Strongly Correlated Electrons
Efficient Optimization of Tensor Rings with Low-Rank Environments
Matthieu Jeannin, Alessandro Chessari and Jan Von Delft
Tensor-ring (TR) decompositions provide a natural representation of periodic systems but are difficult to optimize because the closed geometry prevents a global canonical form and leads to costly, ill conditioned environments. Existing periodic DMRG methods alleviate this difficulty by compressing long environments to a low-rank representation, reducing local operations to $\mathcal{O}(p\chi^3)$, where $p$ is the retained environment rank. Here, we extend this approach to an efficient two-site Ring-DMRG
algorithm and improve its numerical robustness through appropriate gauge transformations and a generalized Davidson solver. A central challenge in the two-site formulation is the truncation step, which must account for the surrounding environment. When this environment is sufficiently separable, a suitable change of frame reduces the truncation to an ordinary SVD. When it is not separable, we instead use an alternating optimization that retains the full environment. The computational advantage of tensor rings over tensor trains depends on the scaling of the required environment rank $p$ with bond dimension and system size. For critical systems, the divergent correlation length makes long-range observables remain sensitive to the periodic geometry as the thermodynamic limit is approached. In this regime, the environment rank required to reach a fixed accuracy in the observable does not grow with the system size. Ring-DMRG therefore retains the same cubic scaling with bond dimension as standard DMRG, but at a substantially smaller bond dimension. The low-rank environment construction also provides a systematic generalization of belief propagation (BP), with standard BP recovered in the rank-one limit.
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Materials Science
Screening of tensor properties by magnetic point group symmetries: The PythMPG code package
Andrea Urru, Turan Birol, Trey Cole et al. (+1 more)
Understanding the
symmetry requirements that permit specific phenomena or physical effects is crucial in condensed matter physics for identifying candidate materials that exhibit one or more of these effects. To this end, screening tensor properties based on (
magnetic) point-group
symmetries is of particular interest. Here, we present the PythMPG code package, a tool designed for this purpose. Inspired by the MTENSOR utility of the Bilbao Crystallographic Server, PythMPG performs
symmetry analysis in a self-contained way to determine which tensors, characterized by their Jahn symbols, are allowed for each
magnetic point group and how many
symmetry-allowed independent components each tensor possesses. We describe the structure of the code and present some illustrative examples.
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All authors Andrea Urru, Turan Birol, Trey Cole, David Vanderbilt