Quantum Gases
Formation and dynamics of self-bound droplets in dipolar molecular condensate
Xinyi Tang, Tianmiao Zhang, Zibin Zhao et al. (+5 more)
We study self-bound
quantum droplets in the regime dominated by microwave-induced non-axisymmetric dipole-dipole interactions, using the extended Gross-Pitaevskii equation with the Lee-Huang-Yang corrections. We identify the existence region through numerical simulations and employ an anisotropic Gaussian-super-Gaussian variational ansätz to capture the characteristic density profile of the droplets, with a Gaussian profile along the narrow $x$ direction and super-Gaussian profiles in the extended $(y,z)$ plane. Within this variational framework, we characterize the self-binding, spatial localization, and density-compression properties of the droplets and find good agreement between the variational predictions and the numerical results. Collisions between droplets moving along different directions reveal a strong directional dependence, with outcomes ranging from quasi-elastic rebound and merger to fragmentation. In addition, we explore the rotational dynamics of a single self-bound droplet about all three Cartesian axes, revealing rich and controllable three-dimensional rotational dynamics. Together, these results demonstrate how non-axisymmetric dipolar interactions provide versatile means for controlling the translational, collisional, and rotational dynamics of self-bound
quantum droplets.
Read the full abstract ▾
All authors Xinyi Tang, Tianmiao Zhang, Zibin Zhao, Guilong Li, Zhaopin Chen, Bin Liu, Boris A. Malomed, Yongyao Li
High Energy Physics (Phenomenology)
Taming Symbolic IBP Reduction with Intermediate Bases
Qian Song
Despite many years of development in integration-by-parts reduction, reconstructing all reduction coefficients, which are rational
polynomials of kinematic variables and the space-time dimension, remains a non-trivial problem. The main difficulty comes from the large number of unknowns in a general ansatz, which can lead to a linear system that is too large to solve. In this paper, we present an
algorithm for reconstructing reduction coefficients through a sequence of intermediate bases. The resulting analytic reduction coefficients are products of a few analytic
matrices, whose non-zero entries are simple rational
polynomials. We demonstrate the efficiency of this
algorithm with two cutting edge examples: a three-point massive box-triangle and a four-point massive pentagon-triangle. Reconstructing all reduction coefficients for the box-triangle (pentagon-triangle) requires 3289 (13013) numerical samplings, significantly fewer than the number of unknowns in the general ansatz, 1407406 (21638331).
Read the full abstract ▾
High Energy Physics (Theory)
The conformal null string in $d+2$ and $d$ dimensions
Ulf Lindström
In [arXiv:2605.26185 [hep-th]] it is pointed out how the tensionless string with a gauged scale
symmetry discussed in the recent articles, [arXiv:2605.12414 [hep-th]], [arXiv:2605.25817 [hep-th]], [arXiv:2605.26822 [hep-th]], is a reduction of the conformal string [arXiv:hep-th/9410143 [hep-th]] to Minkowski space. Here we corroborate this by choices of slices in Dirac $d+2$ dimensional conformal space. We perform a Dirac reduction of the model and its
algebra of constraints and see how they map to the constraints in $d$ dimensions, including how the semidirect product of the Virasoro
algebra with a su(1,1) Kac-Moody
algebra becomes the Corrollian-Weyl
symmetry in $d$ dimensions.
Read the full abstract ▾
Optics
An LLM-Orchestrated Agent for Directional-Coupler Design with Self-Consistent Eigenmode and FDTD Validation
Saumya Biswas, Amrit De and Md Tauhidul Islam
We present a design
agent which is a Large
Language Model (LLM) that orchestrates, but does not perform, the numerical simulations to design a silicon-on-
insulator (SOI) $2\times2$ directional coupler. We choose a symmetric phase-matched coupler where a lot of analytical results are available that help the design strategy. The LLM proposes candidate gap values (a geometrical dimension size) and judges convergence, while all physics is owned by deterministic solvers: a frequency-domain eigenmode solver estimates the coupling coefficient~$\kappa$ for the current design, and an independent Finite-Difference Time-Domain (FDTD) stage validates it. Both solvers operate on a common slab-projected two-dimensional (2D) effective-index reduction of the silicon film, so the design~$\kappa$ and the FDTD response are consistent by problem design; the residual between them is shown to be a single constant phase offset~$\phi$, attributable to a fixed excess coupling length $L_{\mathrm{extra}}=\SI{2.837(11)}{\micro\meter}$ that we find invariant across a factor-of-two range in~$\kappa$. Folding this offset into a closed-loop length correction, the
agent delivers a $50/50$ splitter whose FDTD-measured cross fraction is $0.498$ (target $0.500$), a residual of $0.0017$. Results are made self-consistent within the 2D effective-index model; and the LLM succeeds in delivering a suitable design over a number of attempts.
Read the full abstract ▾
Solar and Stellar Astrophysics
FAUST XXXI. Grain properties and variability of three sources in GSS 30
Q. Yang, H. Baobab Liu, S. Feng et al. (+55 more)
To advance our understanding of
dust properties in class 0/I young
stellar objects, it is crucial to resolve their structures at multiple wavelengths and investigate how grain growth and environmental effects shape their spectral properties. We present 0.5 arcsec resolution ALMA observations of the GSS 30 complex at 1.2-3.0 mm from the FAUST large programme, achieving a linear resolution of 69 au. We analyse the
dust continuum emission and perform modelling to constrain
dust properties and disk structures. For IRS3, the spectral index increases radially from 2.0 at the centre to 2.5 at the disk edge, while decreasing to 1.6-1.8 along the
outflow direction. The asymmetric low-alpha region towards the northeastern blueshifted lobe may result from cold outer envelope
dust obscuring warmer inner regions. SED fitting suggests maximum grain sizes of tens of microns and a
dust mass of 650-1510 M_earth. IRS1 is associated with an extended north-eastern structure, which may represent an
outflow-disk complex, a trailing structure linked to a circumbinary disk, or a gas streamer accreting onto IRS1. The central IRS1 shows alpha < 0.8, consistent with marginally optically thick free-free emission. IRS2 displays brightness variations over 420 s, and multi-epoch comparison suggests a
flare lasting tens of minutes, likely caused by
magnetic activity in the protostar. Our results highlight the importance of environmental effects, including
dust obscuration and streamer structures, in shaping the observed properties of young disks, and reveal millimetre variability associated with possible protostellar
magnetic flares.
Read the full abstract ▾
All authors Q. Yang, H. Baobab Liu, S. Feng, C. J. Chandler, F. Fontani, N. Sakai, Y. Oya, T. Hanawa, C. Codella, C. Ceccarelli, I. Jiménez-Serra, L. Cacciapuoti, E. Bianchi, M. Bouvier, M. De Simone, A. Isella, D. Johnstone, L. Loinard, G. Sabatini, Y. Shirley, Y. Aikawa, M. J. Maureira, P. Caselli, F. Menard, N. Balucani, E. Caux, S. Charnley, N. Cuello, F. Dulieu, L. Evans, D. Fedele, T. Hama, E. Herbst, T. Hirota, B. Lefloch, A. López-Sepulcre, L. T. Maud, A. Miotello, G. Moellenbrock, H. Nomura, Y. Oba, S. Ohashi, Y. Okoda, J. Pineda, L. Podio, A. Rimola, T. Sakai, D. Segura-Cox, B. Svoboda, L. Testi, C. Vastel, S. Viti, N. Watanabe, Y. Watanabe, Y. Zhang, Z. E. Zhang, F. O. Alves, S. Yamamoto
Mesoscale and Nanoscale Physics
Quantum Metric Bound State of Light
Jinchao Zhao, Rongning Liu, Xue-Yang Song et al. (+1 more)
The spatial confinement of defect-induced bound states is conventionally governed by the effective mass in dispersive bands. More recently, Compact Localized States (CLSs) arising from exact destructive interference have been utilized to achieve confinement in flat bands. However, CLSs rely on pristine
lattice symmetries and fine-tuned defect profiles. The introduction of a generic local
impurity inevitably breaks these strict phase-matching conditions, resulting in extensive bound states whose fundamental length scale has remained an open question. Here, we establish a third regime of confinement: the
quantum metric bound state. We provide a rigorous mathematical proof demonstrating that in the absence of kinetic energy and CLS protection, the exponential decay length of these states is lower-bounded by the
quantum metric of the unperturbed flat band. We demonstrate the tightness of this
geometric limit by constructing a family of highly tunable flat-band generators, and we verify its universality across diverse realistic architectures. Ultimately, this classification establishes the independently measurable
quantum metric as a predictive design principle for engineering confined modes in synthetic wave platforms.
Read the full abstract ▾
All authors Jinchao Zhao, Rongning Liu, Xue-Yang Song, K.T. Law
Materials Science · Cross-listed from math.AP
A Classical Elliptic Regularity Approach to Almost Harmonic Maps and Related Systems
Giovanni Di Fratta
We develop an abstract regularity framework for a class of two-dimensional nonlinear
elliptic systems, including almost harmonic maps. The approach combines a Campanato-type iteration scheme with a Caccioppoli-type estimate and identifies general assumptions under which local Hölder continuity follows. More precisely, we prove that any class of admissible pairs $(u,f)$ that is stable under rescaling and satisfies an oscillation-decay property consists of locally Hölder continuous maps. The resulting Hölder exponent is explicit and matches the classical Morrey–Campanato threshold determined by the Lebesgue integrability of the source term $f$. The framework is purely analytic and avoids the use of $\mathcal{H}^1$–$\mathrm{BMO}$ duality, Wente's inequality, moving frames, and conformal uniformization. We illustrate the flexibility of the framework through several classes of
elliptic systems. As a first example, we recover local Hölder continuity for almost harmonic maps \[ -\Delta u=|\nabla u|^2u+f \] into $\mathbb{S}^n$ with $L^q$-integrable tension fields by means of a direct argument independent of the classical harmonic map regularity theory. We next consider systems of the form \[ -\Delta u=\Omega\cdot\nabla u+f, \] showing that the analytic condition $\operatorname{div}\Omega\in L^q$ for some $q>1$ is sufficient to ensure regularity (for classical harmonic maps, $\operatorname{div}\Omega=0$). We further apply the framework to...
Read the full abstract ▾
High Energy Physics (Experiment)
Searches for resonant and nonresonant multi-Higgs production in ATLAS and CMS
Emmanouil Vourliotis
The measurement of the
Higgs boson self-coupling is one of the key physics goals of the LHC program, providing direct access to the shape of the
Higgs potential and offering sensitivity to physics beyond the Standard Model (BSM).
Higgs pair production probes the trilinear self-coupling, while triple
Higgs production is sensitive to the quartic coupling. In addition, resonant searches for heavy scalars decaying to pairs of
Higgs bosons or to a
Higgs boson and a new scalar are motivated by a broad class of BSM models. Recent results on multi-
Higgs production searches from the ATLAS and CMS experiments at the Large
Hadron Collider (LHC) are presented, covering both resonant and nonresonant production modes across a variety of final states.
Read the full abstract ▾
High Energy Physics (Theory)
Ru-Qing Chen, Hui Zeng and Zhang-Yu Nie
We investigate a
holographic s+p
superconductor model coupled to nonlinear electrodynamics in the probe limit. The equations of motion are solved numerically, and the condensates as well as the grand potential curves for phase transitions at different values of the nonlinear parameter $b$ are illustrated. It is found that as $b$ increases, both the pure s-wave and p-wave condensates are suppressed. From the $b-T$ phase diagram, we observe that the region of the pure s-wave phase gradually shrinks with increasing $b$, which is attributed to the stronger suppression on the s-wave condensate compared to the one on the p-wave. Moreover, a smaller charge ratio $q_p/q_s$ is needed for the s+p coexistent phase to appear as $b$ grows. A particularly interesting feature is that, due to the nonlinear self-interaction of the electromagnetic field, charge accumulates spontaneously outside the event horizon from the bulk perspective even in the absence of scalar and vector condensates, thereby invalidating the conventional formula for the superconducting charge density. We improve the definition of the superconducting charge density as the background-subtracted value of the accumulated charge outside the horizon with respect to that in the normal phase. Furthermore, the optical conductivity in the normal phase is also modified by this accumulated charge for finite $b$, and its imaginary part develops a minimum at a finite frequency. This minimum persists in the superconducting phase near the critical point, confusing the extraction of the gap frequency.
Read the full abstract ▾
Nuclear Experiment
Hyper-Nuclei $^4_{\Lambda}\hbox{He}$ Production in $\sqrt{s_{\rm{NN}}}$ = 3 GeV Au+Au collisions at RHIC
The STAR Collaboration
The
STAR experiment reports the first measurement of the $^4_{\Lambda}\hbox{He}$ hyper-
nuclei yield as a function of rapidity and transverse momentum in 0-50% central Au+Au collisions at $\sqrt{s_{\rm{NN}}} =$ 3 GeV. The $^4_{\Lambda}\hbox{He}$ is reconstructed through its three-body decay channel, $^4_{\Lambda}\rm{He} \rightarrow {}^{3}\rm{He} + \rm{p} + \pi^-$, with a statistical significance of about 9.5 standard deviations. We find that the yield of $^4_{\Lambda}\hbox{He}$ as a function of rapidity is consistent with that of $^4_{\Lambda}\hbox{H}$, and the rapidity-dependent yield ratio of $^4_{\Lambda}\hbox{He}$/$^4_{\Lambda}\hbox{H}$ is consistent with that of $^3$He/t. All the measurements, as well as the transverse-momentum spectra, can be reasonably described by the JAM with a coalescence afterburner, suggesting a coalescence-based formation scenario for hyper-
nuclei at this energy. The canonical thermal model reproduces the observed yield ratios but overpredicts the absolute hyper-
nuclei yields.
Read the full abstract ▾
Earth and Planetary Astrophysics
Julia V. Seidel, Vivien Parmentier, Bibiana Prinoth et al. (+29 more)
Magnetic fields are ubiquitous in the universe. They play a key role in shaping the activity of
stars, the habitability of rocky
planets, and the long-term retention of planetary atmospheres. Theoretical scaling laws are largely constrained by the limited set of
stars and
Solar System
planets, leading to a wide range of possible values for hot
giant planets outside of the
Solar System from fractions of the Jovian field to orders of magnitude larger. Ultra-hot Jupiters, with their highly ionised atmospheres, provide a new avenue to probe
magnetic effects, as their atmospheric circulation could be directly sensitive to atmospheric
magnetic field strength. Using high-spectral resolution observations targeting the iron lines of ultra-hot Jupiters we measure the Doppler shift and thus the wind speed of seven transiting ultra-hot Jupiters. We find a clear decrease of wind speed with increasing planetary temperature, a trend inconsistent with purely hydrodynamic mechanisms but naturally reproduced by
magnetic drag. From this relation we estimate the possible strength of
magnetic fields of hot
giant planets to at most a few gauss - comparable to the Jovian equatorial field. Our results support the idea that
magnetic fields affect the atmospheric circulation of ultra-hot Jupiters and could provide a crucial
benchmark for scaling laws used to predict
magnetic fields in
exoplanets, from hot Jupiters to rocky Earths with additional implications for future direct observations.
Read the full abstract ▾
All authors Julia V. Seidel, Vivien Parmentier, Bibiana Prinoth, Thea Hood, Nishil Mehta, Valentin De Lia, Konstantin Batygin, Tristan Guillot, Ragnar Van den Broeck, Hayley Beltz, Brian Thorsbro, Florian Debras, Daniel D. B. Koll, Thaddeus D. Komacek, Emily Rauscher, Lorenzo Pino, Matteo Brogi, Joost P. Wardenier, Jacob L. Bean, Björn Benneke, Jean-Michel L. B. Désert, Pablo Drake, Siddharth Gandhi, Mark Hammond, David Kasper, Michael R. Line, Elspeth K. H. Lee, Stefan Pelletier, Andreas Seifahrt, Adrien Simonnin, Peter C. B. Smith, Kevin B. Stevenson
Statistical Mechanics · Cross-listed from q-bio.QM
Kinetics of multistate DNA polymerases
Pierre Gaspard
In the present paper, we apply the iterative mathematical method previously developed for the kinetics of template-directed multistate copolymerization to the kinetics of DNA replication by polymerases having multiple structural states. In particular, we study a two-state kinetic model for the T7 DNA polymerase. We obtain the mean velocity for the growth of the copy along the template, the error probability of DNA replication by the polymerase, and the local probabilities of base-pair formation along the template sequence. Furthermore, we show that the iterative method is more than a million times faster than usual numerical simulation methods. Results are also obtained in the approximation of homogenization of template heterogeneities.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from q-bio.QM
Kinetics of template-directed multistate copolymerization
Pierre Gaspard
We consider processes of template-directed multistate copolymerization by molecular machines such as polymerases or ribosomes, having multiple states of conformation or activation. We show that the kinetic equations of these processes can be exactly solved for the mean growth velocity, the sequence probabilities of the grown copy, and the local probabilities and fractions of monomeric units in the copy. Asymptotically, in the long-time limit, the kinetic equations are solved with a
matrix factorization ansatz in terms of a backward iteration, forming an iterated
matrix function system, and a complementary forward iteration, both running along the template sequence. The iterative method is very significantly faster than usual computational methods, as demonstrated with a numerical example.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Unified Mass-Scaled QPO Signatures of Kerr Sen Black Holes from Stellar Mass to Supermassive Sources
Orhan Donmez and G. Mustafa
In this study, we numerically investigate Bondi-Hoyle-Lyttleton (BHL)
accretion around Kerr-Sen black holes and examine how the charge-related deformation of the spacetime affects the shock-cone morphology, the variation of the mass
accretion rate, and the quasi-periodic oscillation (QPO)-like temporal behavior. The relativistic BHL flow is solved numerically in the equatorial plane for two different black hole
spin parameters, a = 0.9 M and a = 0.5 M. From the numerically computed mass
accretion rate signal, we calculate the power spectral density (PSD) and perform multi-component Lorentzian fits to identify the dominant QPO-like modes excited around the black hole. The results show that the Kerr-Sen deformation shifts the characteristic frequencies, changes the coherence properties of the oscillation modes, and produces near-resonant harmonic structures close to 3:2 and 2:1. By using inverse mass scaling, the numerically computed frequencies are compared with observed QPOs from
stellar-mass, intermediate-mass, and supermassive black hole systems. In particular, reasonable agreement between the numerical simulation results and observations is found for the sources GRS 1915+105, IGR J17091-3624, M82 X-1, NGC 5408 X-1, RE J1034+396, 1H 0707-495, and ESO 113-G010. This comparative analysis indicates that Kerr-Sen black hole shock-cone oscillations may provide a unified framework for interpreting timing features over a broad range of black hole masses and may additionally contribute to constraining the mass and
spin parameters of sources whose properties are not yet fully established observationally. These findings further imply that combined hydrodynamical and timing diagnostics constitute a promising approach for assessing the extent to which deviations associated with the Kerr-Sen geometry can be empirically distinguished from those of the Kerr spacetime.
Read the full abstract ▾
Mathematical Physics
Localized oscillations of an Euler–Bernoulli beam with time-varying parameters on a visco-elastic foundation: asymptotics, adiabatic invariant, and equivalent Hamiltonian system
Ekaterina V. Shishkina, Serge N. Gavrilov and Yulia A. Mochalova
We consider localized oscillations of an Euler–Bernoulli beam on a visco-elastic foundation coupled to a damped discrete oscillator. All system parameters vary slowly and independently in time. For the conservative case, we employ three different analytical approaches: an asymptotic method, a technique based on the adiabatic invariance of the action of a trapped wave, and an analysis of the equivalent
Hamiltonian system. All three approaches yield the identical formula for the oscillation amplitude. In the dissipative case, the oscillation amplitude is obtained solely via the asymptotic approach. Finally, we validate our analytical findings against numerical simulations, demonstrating excellent agreement.
Read the full abstract ▾
Biological Physics
Data-driven geometric phase in biological locomotion
Pyae Hein Htet and Kenta Ishimoto
Geometric phase quantifies net locomotion in dissipative media via gauge theory, but linking this theoretical quantity to noisy, sparse, and weakly periodic biological shape data is challenging. We develop a theory-guided, data-driven Koopman autoencoder to recover the limit cycle embedded in imperfect cyclic data and extract shape gaits and
geometric phase from sperm and nematode data. We introduce a
geometric phase sensitivity function that quantifies responses to shape perturbations and reveals mechanical information using only gauge-theoretic structure, without assuming mechanical laws.
Read the full abstract ▾
Exactly Solvable and Integrable Systems
Long-time asymptotics of a full arbitrary-genus dark soliton gas for the defocusing nonlinear Schrodinger equation
Dedi Yan, Xianguo Geng and Mingming Chen
We introduce a full arbitrary-genus dark
soliton gas for the defocusing nonlinear Schrödinger equation with finite-density boundary conditions. Starting from a generalized meromorphic Riemann–
Hilbert problem with two alternating residue families on each unit-circle arc, we derive an exact thermodynamic limit whose jump
matrix contains two nonzero continuum densities. The limiting Riemann–
Hilbert problem is uniquely solvable. In contrast with the half dark-
soliton gas, every spectral arc of the full gas carries both oscillatory exponentials. We analyze the resulting problem by the Deift–Zhou nonlinear steepest-descent method on a fixed genus-$N$ spectral curve. The moving point in each mixed sector is a stationary factorization-switching point, not a branch point. The active arc is split into two parts and opened crosswise, while lenses are opened around every remaining arc. After removal of exponentially small lens jumps, the model contour therefore retains all $N$ spectral arcs in every self-similar sector. A quotient-curve zero-counting argument proves strict monotonicity of the characteristic velocity and the global ordering of all endpoint velocities, so the self-similar line is divided into $2N+1$ nonempty sectors. The leading term is an $N$-dimensional Riemann-theta finite-gap solution. The error is $O(t^{-1})$ in the $N+1$ pure sectors and $O(t^{-1/2})$ in the $N$ mixed sectors, uniformly away from the critical rays.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Tracing Large-scale Structure with the MeerKLASS On-the-Fly Survey: Angular Clustering of Radio Sources at 816 MHz
Sourabh Paul, Suman Chatterjee, Keith Grainge et al. (+8 more)
We present the first measurement of the angular two-point correlation function \(w(\theta)\) of
radio sources from the MeerKAT Large Area Synoptic Survey (MeerKLASS) UHF on-the-fly (OTF) continuum Data Release~1. DR1 provides interferometric Stokes-\(I\) imaging at a reference frequency of 816\,MHz over \(\sim 800~\mathrm{deg}^2\) within the DESI footprint. We detect a positive clustering signal over \(0.02^\circ \lesssim \theta \lesssim 10^\circ\). The measurement is stable to reasonable variations of the depth mask and flux threshold on intermediate and large scales. Modelling the intermediate-scale signal (\(0.112^\circ\le\theta\le 1.36^\circ\)) with a fixed-slope power law (\(\gamma=1.8\)) yields \(A(1^\circ)=(1.434\pm0.475)\times10^{-3}\), corresponding to \(\log_{10}A=-2.843^{+0.124}_{-0.175}\). We infer an effective large-scale bias by fitting \(\Lambda\)CDM projected-matter templates \(w_{\rm DM}(\theta)\) computed with CAMB and Limber projection, including an integral-constraint correction evaluated from random–random weights. Using two bracketing T-RECS
redshift-distribution priors, we obtain \(b_{\rm eff}=1.998\pm0.350\) (AGN prior) and \(b_{\rm eff}=1.530\pm0.265\) (TOTAL prior), demonstrating that the dominant modelling uncertainty arises from \(N(z)\). As a derived summary we Limber-invert the power-law amplitude to obtain \(r_0=6.18\pm1.13\) and \(5.59\pm1.02~h^{-1}\mathrm{Mpc}\) for the AGN and TOTAL priors, respectively. These results establish MeerKLASS UHF DR1 as a new wide-area, intermediate-frequency
dataset for
radio-continuum clustering. As MeerKLASS expands and overlapping optical/IR spectroscopy provides improved
redshift calibration, future releases will enable population-split clustering and bias
evolution measurements with substantially reduced modelling uncertainty.
Read the full abstract ▾
All authors Sourabh Paul, Suman Chatterjee, Keith Grainge, Laura Wolz, Aishrila Mazumder, Steven Cunnington, Sarvesh Mangla, Joseph J. Mohr, Mario G. Santos, Oleg Smirnov, Cyril Tasse
General Relativity and Quantum Cosmology
An Interplay Between Fractional Calculus and Holographic Dark Energy
Ayush Bidlan
This dissertation aims to put forth a systematic construction of a fractional-calculus extension of
holographic dark energy (HDE). We show that linking late-time
cosmic acceleration to non-local or
memory effects encoded in a fractional (Riesz) derivative within black hole thermodynamics produces deviations from standard HDE and can address some challenges of the Hubble cutoff. In particular, a Riesz fractional spatial derivative is introduced into the
Hamiltonian constraint of a Schwarzschild black hole in
quantum geometrodynamics, leading to a Fractional Wheeler–DeWitt equation whose solutions yield fractionally corrected thermodynamic quantities, notably fractional Bekenstein–Hawking
entropy governed by the Lévy index \(\alpha\), with \(1<\alpha\leq2\). Using this
entropy with Cohen's inequality, a new dark energy density is constructed, defining the Fractional
Holographic Dark Energy (FHDE) framework. The cosmological implications of FHDE are then investigated. Within the Hubble cutoff, its late-time
evolution is analysed through cosmological observables, and the model is reconstructed using effective field descriptions with
spin-\(0\) and
spin-\(1\) candidates, allowing kinetic and potential terms to be extracted as functions of
redshift \(z\) and \(\alpha\). The framework is then extended to BD, DGP, EPN, and Horndeski theories to derive the equation-of-state and deceleration parameters in terms of \(z\) and \(\alpha\). In addition, the fate of the Universe is studied through late-time singularities, namely the big, little, and pseudo-rip, within the Granda–Oliveros FHDE setting. In short, this dissertation proposes FHDE as a theoretically motivated extension of HDE, bridging non-locality in
quantum gravity with the late-time dynamics of the Universe, and offering a route toward understanding
cosmic acceleration beyond \(\Lambda\)CDM.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Analytical calculation of the spectrum of nonlinear Compton scattering beyond local approximations
M. P. Malakhov, Th. Benahmed, E. G. Gelfer et al. (+4 more)
We derive compact analytical formulae for the spectrum of nonlinear Compton scattering in a finite plane-wave pulse with a smooth temporal envelope. The strong-field QED probability is reduced to finite-pulse phase integrals, which are evaluated asymptotically for multicycle pulses with a broad class of smooth envelopes. We use the uniform approximation to remove the caustic divergences that appear at the nonlinear edges of broadened harmonics. Away from the caustics, it reduces to the standard saddle-point result. The behavior near the linear edge is further improved by an envelope-corrected saddle-point approximation. The approach retains the harmonic substructure in the spectral-angular region carrying the dominant part of the emitted radiation. The locally monochromatic approximation is recovered by averaging the finite-pulse interference. Within their asymptotic domain of applicability, the resulting formulae agree with direct numerical calculations and can be used to evaluate spectra from an electron beam.
Read the full abstract ▾
All authors M. P. Malakhov, Th. Benahmed, E. G. Gelfer, A. M. Fedotov, O. Klimo, S. Weber, S. G. Rykovanov
Materials Science · Cross-listed from cs.AI
SVGym (SciVerseGym): An Environment for Reinforcement Learning and Bayesian Optimization in Crystal Discovery
Bin Cao
Machine-learned interatomic potentials now enable efficient atomistic evaluation for interactive materials discovery, yet closed-loop
crystal search methods remain fragmented across bespoke pipelines for editing, relaxation, scoring, constraints, and bookkeeping. We introduce SciVerseGym, a Gymnasium-compatible environment for sequential
crystal discovery that frames
crystal design as a Markov decision process.
Agents observe an atomistic structure, apply chemically meaningful edits, and receive feedback from a configurable evaluator. SciVerseGym supports local and global actions, including elemental substitution,
lattice perturbation, atomic displacement, vacancy creation, and atom insertion, along with configurable chemical spaces, structure pools, atomistic and graph-based observations, custom rewards, optional relaxation, and stability or
phonon-related diagnostics. Each step applies an edit, evaluates the candidate using a machine-learned interatomic potential or any ASE-compatible calculator, and returns the standard (obs, reward, terminated, truncated, info) tuple. By decoupling
agent logic from materials infrastructure, SciVerseGym provides an open, reproducible, and extensible testbed for reinforcement learning,
Bayesian optimization, evolutionary search, and
language-
agent workflows in closed-loop
crystal discovery. Code is available at: https://github.com/Bin-Cao/SciVerseGym.
Read the full abstract ▾
Quantum Physics
A Three-Layer Architecture for Fault-Tolerant Quantum Computing
Zhirao Wang, Zhou You, Yiming Huang et al. (+4 more)
Fault tolerance is an indispensable prerequisite for constructing large-scale universal
quantum computers. Drawing philosophies from classical computer architecture, this paper presents a hardware-agnostic three-layer high-level architectural framework for generic fault-tolerant
quantum computation. Guided by the real execution workflows of fault-tolerant
quantum algorithms, the proposed model is decoupled from specific physical
qubit hardware platforms and
quantum error correction codes, serving as a universal abstract standard rather than a platform-specific implementation scheme. Special
attention is devoted to the intermediate Fault-Tolerance Layer, which serves as the architectural bridge between application-level logical programs and hardware-level execution. We systematically characterize its five internal components, the interfaces and data exchanged among them, and the execution, correction, and adaptation paths that together enable logical synthesis, fault-tolerant resources management, decoding, and runtime fault-tolerant control. An end-to-end example is further provided to illustrate the full-stack operating pipeline of fault-tolerant
quantum algorithms under this framework. Given the increasing emphasis on modular, heterogeneous, and cross-layer fault-tolerant
quantum systems, our architecture provides a unified foundational model for organizing such designs.
Read the full abstract ▾
All authors Zhirao Wang, Zhou You, Yiming Huang, Tianyi Li, Ying Li, Xiao Yuan, Yuan Yao
Cosmology and Nongalactic Astrophysics
Shape-Preserving Evolution of the Global Ultraviolet Quasar Luminosity Function to $z\simeq7.5$
Wenjie Wang, Zunli Yuan, Yu Luo et al. (+1 more)
We present a global unbinned-likelihood analysis of the rest-frame ultraviolet (UV)
quasar luminosity function (QLF) over $0.1\le z\le7.5$, using a final analysis sample of 70,960 Type~1
quasars selected from the homogenized compilation of Kulkarni et al. (2019). We test a shape-preserving luminosity and density
evolution (LADE) framework, in which the local luminosity function (LF) shape is fixed and the
redshift evolution is described by separate density- and luminosity-
evolution factors. For a double-power-law (DPL) local LF, we search 81 LADE models built from nine density-
evolution and nine luminosity-
evolution functions, and compare them with two flexible double-power-law (FDPL) reference models. The fiducial shape-preserving LADE model gives the lowest Akaike information criterion (AIC) and
Bayesian information criterion (BIC) values among the main models considered, and 12 DPL-based LADE models have lower AIC and BIC values than both FDPL reference models. Repeating the model-grid analysis with a modified-Schechter local LF gives the same preferred evolutionary structure, indicating that the result is not driven only by the assumed local LF shape. The fitted
evolution functions further show that the luminosity-
evolution component is the more stable part of the LADE decomposition: it rises rapidly to $z\simeq2$–3 and then flattens or slowly declines. The density-
evolution component is more model dependent, but the preferred LADE models consistently require a declining effective normalization toward high
redshift. Taken together, we conclude that a shape-preserving framework offers a statistically efficient and compact empirical description of the global UV QLF.
Read the full abstract ▾
All authors Wenjie Wang, Zunli Yuan, Yu Luo, Longhua Qin
High Energy Physics (Phenomenology)
Probing Anomalous $t{\bar q}Z$ Interactions at Muon Colliders
Liangliang Shang, Lu Zhang, Bingfang Yang et al. (+1 more)
In the framework of effective field theory, we study the anomalous $t{\bar q}Z$ interaction through the process $\mu^+\mu^- \to t{\bar q}Z$ at future
muon colliders with $\sqrt s= 3, 10, 14\,\text{TeV}$. Based on the top
quark decay modes involving $W$ and $Z$
bosons, we first divide the signal into six cases. Then, in order to obtain the limits on the corresponding branching ratios, we perform a detector simulation for both signals and Standard Model backgrounds. To enhance the signal significance, we exploit the polarization of the
muon beams and employ the fat jet method to reconstruct signals in hadronic final states. For $\sqrt s= 14\,\text{TeV}$ with $20\,\text{ab}^{-1}$, we find that the upper limit on the branching ratio for $t\to qZ$ can reach the order of $\mathcal{O}(10^{-8})$, which exceeds the limits provided by the CMS and ATLAS collaborations by 2 to 3 orders of magnitude. Our study thus demonstrates that TeV-scale
muon colliders can provide an efficient and complementary platform for probing rare top
quark interactions.
Read the full abstract ▾
All authors Liangliang Shang, Lu Zhang, Bingfang Yang, Stefano Moretti
General Relativity and Quantum Cosmology
Starobinsky-inflation in asymptotically safe shift-symmetric scalar-tensor theory
Benjamin Koch, Cristobal Laporte and Frank Saueressig
We investigate the constraining power of scalaron-driven inflation on asymptotically safe scalar-tensor theories. Starting from a Horndeski-type theory and applying a renormalization group improvement procedure generates higher-derivative couplings which are fixed in terms of the microscopic parameters - a structure that is expected to occur also within first principle computations based on the asymptotic safety mechanism. The latter are taken to be the free parameters appearing at the Gaussian fixed point. We find that the free parameter initially associated with the non-minimal
gravity-matter coupling is not confined to the
gravity-matter sector of the theory and also enters the effective higher-derivative couplings in the gravitational sector. We review the setting of multi-field inflationary models which is appropriate to analyze the inflationary dynamics in this context and illustrate their applicability by working out the explicit bounds on the non-minimal
gravity-matter coupling resulting from cosmological observations. Given the fixed point structure of asymptotically safe scalar-tensor theories, the results indicate that UV-completions by two of the three available non-Gaussian fixed points can be ruled out while pinpointing phenomenologically viable RG trajectories emanating from the third fixed point.
Read the full abstract ▾
Statistical Mechanics
Perturbative Renormalization and Universality Diagram for Long-Range Quantum Criticality
Zhiyi Li, Zhijie Fan, Kun Chen et al. (+1 more)
Experimental progress in
quantum simulators highlights the role of long-range (LR) interactions in reshaping
quantum criticality and stabilizing exotic phases beyond the short-range (SR) paradigm. We study
ferromagnetic long-range
quantum $O(n)$ models with interactions decaying as $1/r^{d+\sigma}$ and develop a perturbative renormalization-group expansion around the LR–SR boundary by setting $d=3-\epsilon$ and $\sigma=2-\delta$. In this parametrization, the full interacting LR window $2d/3<\sigma<2$ becomes $0<\delta<2\epsilon/3$, and is therefore perturbatively controlled. A two-loop calculation yields explicit expressions, in terms of $\epsilon$, $\delta$, and $n$, for the correlation-length exponent $\nu$ and for the frequency and momentum anomalous dimensions $\eta_\omega$ and $\eta_k$. The resulting exponents reduce to long-range Gaussian scaling at $\sigma=2d/3$ and to SR
quantum Wilson-Fisher scaling in the $\sigma \to 2$ limit, thereby identifying $\sigma_*=2$ as the LR–SR boundary within the controlled $3-\epsilon$ expansion. Combining the RG results with scaling boundaries and classical LR analogies, we propose a $(d,\sigma)$ universality diagram for
ferromagnetic long-range
quantum $O(n)$ criticality and use it as an organizing framework for the phase diagram of long-range
quantum spin chains.
Read the full abstract ▾
All authors Zhiyi Li, Zhijie Fan, Kun Chen, Youjin Deng
Quantum Physics
Quantum Otto engine with field-decoupled idle levels in a non-Hermitian XY model
Maimaitiyiming Tusun and Fang Zhao
We propose a microscopic realization of the idle-level
quantum heat engine architecture based on a two-
qubit non-Hermitian XY model with a staggered imaginary
magnetic field. The energy spectrum naturally separates into two working levels coupled to the external field and two field-decoupled idle levels entirely independent of it. Tuning the non-Hermitian parameter drives the system from a dissipative accelerator regime into a genuine heat engine regime, while simultaneously enhancing both the net work output and the cycle efficiency. The efficiency enhancement originates from the compression of the idle-level gap, which redistributes level occupations and progressively suppresses the idle-level heat current, signalling the approach to the reverse heat-flow regime that underlies the idle-level engine principle. We map the full thermodynamic phase diagram identifying engine, refrigerator, accelerator, and heater regimes, and decompose the heat current into working-level and idle-level contributions to clarify the microscopic origin of the performance gain. The model is implementable in trapped-ion and NMR
quantum simulators. These results establish non-Hermiticity as a versatile control knob for idle-level
quantum thermal machines.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Null geodesic defocusing in dynamical black-hole-to-white-hole transitions
Johanna Borissova, Stefano Liberati and Matt Visser
We investigate the defocusing of null geodesics in dynamical, non-singular black-hole-to-white-hole transitions. Working at the level of spacetime kinematics, and without assuming any specific gravitational field equations, we show that the contraction and disappearance of a trapped region, as well as the subsequent formation and expansion of an anti-trapped region, necessarily require a violation of the null convergence condition. This conclusion follows directly from the behaviour of the null expansions across the trapping and anti-trapping horizons, and is therefore independent of the microscopic mechanism responsible for singularity resolution. We then illustrate this general argument by constructing a class of explicit bouncing geometries in generalised Painlevé-Gullstrand coordinates, obtained by promoting static regular black holes with de Sitter cores to time-dependent black-hole-to-white-hole transition models. For a Bardeen-type mass function, we show that the required violation of the null convergence condition is localised within the intermediate dynamical phase in which the trapped region evaporates and the anti-trapped region forms. Finally, we argue that the limiting case of an instantaneous black-hole-to-white-hole transition would require an unbounded violation of the null convergence condition, signalling a breakdown of the effective continuum metric description, and the need to appeal to a full
quantum-gravitational description.
Read the full abstract ▾
Disordered Systems and Neural Networks
Percolation of Zero-Weight Paths and the Shape of the Phase Boundary in the Two-Dimensional Random-Bond Ising Model
Amirhossein Manouchehri and Kirill Shtengel
We explore the connection between the low-temperature boundary of the
ferromagnetic phase in the two-dimensional $\pm J$ random-bond Ising model, where
antiferromagnetic bonds occur with probability $p$ and a
geometric transition dubbed “zero-weight percolation”. We argue that the onset of this percolation characterized by the emergence of a percolating path containing an equal number of $+J$ and $-J$ bonds is incompatible with
ferromagnetic ordering. Due to its purely geometrical nature, this percolation criterion is a property of a disorder realization and is independent of the temperature, which in turn suggests that the
ferromagnetic phase boundary is vertical below the Nishimori point in the $(p,T)$ plane. Using a dynamic-programming
algorithm combined with finite-size scaling, we identify the critical disorder at which zero-weight paths first percolate as $p_c = 0.1000(2)$, and we extract the associated critical exponents $\nu = 1.26(1)$, $\beta/\nu = 0.85(1)$, $\gamma/\nu = 0.264(5)$, and fractal dimension $d_f \approx 1.11$. The value of $p_c$ is below the previously reported values of the critical disorder strength corresponding to the loss of the
ferromagnetic order, both at zero temperature and the Nishimori point. Nevertheless, we argue that the percolation transition studied in this paper is behind the loss of ferromagnetism and thus provides a new, purely geometrical perspective on the stability of
ferromagnetic order in disordered
spin systems.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Pseudo-scalar dark matter from a broken gauged symmetry
Junho Kang, Sarif Khan, Jongkuk Kim et al. (+1 more)
We propose a novel model for pseudo-scalar dark matter (PSDM) by extending the Standard Model (SM) with a dark gauged $U(1)_X$
symmetry, but without dark charged
fermions. We impose a $Z_2$
symmetry to ensure the stability of pseudo-scalar dark matter and regard the $U(1)_X$
symmetry as being broken dominantly by a large VEV of the singlet scalar field. The would-be Goldstone associated with the $U(1)_X$ gauge
boson is almost orthogonal to the direction of PSDM. As a result, we show that PSDM appears as a stable pseudo-Nambu-Goldstone
boson receiving the mass from the $U(1)_X$ invariant mixing potential and the corresponding cross section for direct detection gets suppressed even for the weak-scale mass of PSDM. We also show that the correct relic density can be explained by the PSDM annihilations into the SM particles or into a pair of light
Higgs-like scalars, being compatible with the bounds from
Higgs invisible decay,
Higgs data and indirect detection.
Read the full abstract ▾
All authors Junho Kang, Sarif Khan, Jongkuk Kim, Hyun Min Lee