Solar and Stellar Astrophysics
Early Planet Formation in Embedded Disks (eDisk). XXIV: Systematic Investigation of Disk Structures based on Visibility Analysis
Mayank Narang, Jerry Xu, Leslie W. Looney et al. (+11 more)
The
dust continuum emission from young protostellar disks encodes key information about their mass distribution and early
evolution, yet uniform high-resolution comparative studies remain limited. We present a systematic uv-plane analysis of parametric intensity models applied to ALMA Band-6 (1.3 mm) observations of 23 disks (19 protostellar systems with 4 being in binary) from the eDisk sample, spanning Gaussian profiles to power-law cores with exponential tails (PLCT), including asymmetric extensions. Gaussian models generally fail to reproduce the centrally peaked emission and extended outer structure observed in most disks, whereas the PLCT framework provides a significantly improved description of radial brightness profiles. Incorporating azimuthal asymmetries further reduces residuals in 15 of 17 inclined disks, indicating that departures from axisymmetry are common at early stages. Only two disks, L1489 IRS and Oph IRS63, exhibit clear gap and ring substructures, while most appear smooth at the spatial resolution and sensitivity of our observations. These systems are among the most evolved in the sample, and the absence of flat-spectrum sources limits the evolutionary range probed, {suggesting that the detection of prominent gaps and rings is not common} in the earliest phases of disk
evolution. Using a uniform definition of disk radius based on the 95% enclosed flux, we find a positive correlation with
stellar mass, $R_{\rm disk} \propto M_{\star}^{1.5 \pm 0.1}$, with disks in binary systems systematically smaller than those around isolated protostars. While the models capture overall morphology and large-scale asymmetries, distinguishing intrinsic structures from radiative transfer effects in optically thick regions remains challenging.
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All authors Mayank Narang, Jerry Xu, Leslie W. Looney, Nagayoshi Ohashi, Anika Khandavalli, Patrick Sheehan, Jonathan P. Williams, Shigehisa Takakuwa, Jes K. Jørgensen, Ilseung Han, Woojin Kwon, Zhi-Yun Li, Nguyen Thi Phuong, John J. Tobin
Mesoscale and Nanoscale Physics
Channel-selective magnetic filtering in a nodal-line semimetal
Hironmoy Pratihar, Alessandro De Martino and Arijit Kundu
We study
quantum transport through a
magnetic barrier in a nodal-line semimetal. When the
Fermi energy lies near the nodal ring, the
Fermi surface has toroidal geometry. Each cross-section in a plane parallel to the nodal ring consists of two concentric contours, inner and outer, carrying distinct transport channels. We show that a
magnetic barrier resolves these two channels: because the contours enclose different momentum-space areas, they accommodate the field-induced transverse-momentum shift unequally, and the inner channel is cut off at a weaker barrier strength than the outer. Using a two-band effective
Hamiltonian and a wave-function matching approach, we obtain closed-form, channel-resolved transmission amplitudes. Over a finite window of barrier strength the inner contour is fully blocked while the outer still transmits, so the barrier acts as a channel-selective filter. This sequential quenching shapes the two-terminal conductance, which decreases with barrier strength as the two channels close in turn and terminates once the outer channel is cut off, providing experimentally accessible fingerprints of the toroidal
Fermi surface of a nodal-line semimetal.
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High Energy Physics (Theory)
Quantum effects of charged massive scalar fields on charged black hole space-times
Cormac Breen, George Montagnon, Peter Taylor et al. (+1 more)
We compute the renormalized expectation values of the scalar condensate, charge current and stress-energy tensor for a massive charged
quantum scalar field on a Reissner-Nordstrom black hole. The mass of the scalar field is sufficiently large that classical superradiance is absent. We present results for the Boulware, Unruh and Hartle-Hawking states. Renormalized expectation values in the Hartle-Hawking state are computed using an efficient and accurate mode sum prescription, and for the other two states we employ state subtraction. The efficiency of our numerical method enables us to explore a large part of the parameter space, including near-extremal black hole charges and scalar field masses close to the superradiant limit.
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All authors Cormac Breen, George Montagnon, Peter Taylor, Elizabeth Winstanley
Mathematical Physics · Cross-listed from math.PR
An optimal Poincaré inequality for the complex Ginibre log-gas
Djalil Chafaï
We establish an optimal Poincaré inequality for real-valued symmetric observables of the complex Ginibre log-gas. Equality is attained by the real and imaginary parts of the center-of-mass observable. Equivalently, we determine the exact spectral gap of the associated overdamped Langevin dynamics, for real symmetric observables. The Hessian of the energy of this log-gas is unbounded below, so standard convexity arguments do not directly apply. The proof instead combines a Vandermonde transform, a holomorphic projection, and a complex Gaussian d-bar spectral-gap estimate, corresponding to the constant-
curvature case of the Hörmander-Berndtsson estimate. It is short and self-contained. It remains valid, beyond the quadratic potential, for rotationally invariant additive plurisubharmonic potential perturbations. Additionally, we provide four alternative proofs, two of which yield sum-of-squares formulas for the deficit, based respectively on a Hermite expansion and on an integrated Bochner-Kodaira formula, the other two use the spectral analysis of a two-sided number-operator factorization and a Hermite-Slater
polynomial expansion. We furthermore present new results related to linear statistics, Gaussian factorization,
polynomial eigenfunctions, log-Sobolev inequalities,
matrix lift and eigenvector overlaps, and non-quadratic potentials.
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Optics
Black-Box Coherence Matrix Eigen-Spectroscopy with Programmable Photonics
Kevin Zelaya, Jonathan Friedman and Mohammad-Ali Miri
The precise characterization of spatial optical coherence is fundamental to emerging applications in optical communications and computational imaging. However, extracting the full coherence
matrix traditionally requires phase-sensitive interferometry, which is highly vulnerable to environmental noise and poses severe scalability challenges for integrated photonics. Here, we introduce an architecture-agnostic framework for analyzing and controlling partially coherent light on programmable photonic
circuits. By leveraging the Schur-Horn
theorem, our approach systematically diagonalizes the incident coherence
matrix, relying solely on output intensity measurements and entirely circumventing the need for complex phase
retrieval. We experimentally validate this black-box protocol on a low-depth, non-universal photonic integrated
circuit, successfully reconstructing the hidden
eigenvalues of mixed states generated from up to four mutually incoherent sources. Furthermore, we demonstrate active, in-situ statistical light control by introducing non-
unitary amplitude modulation to significantly enhance interference visibility, exposing a fundamental physical trade-off between coherence enhancement and optical loss. Inherently resilient to hardware constraints and experimental noise, this scalable paradigm establishes a robust pathway for realizing ultra-compact, on-chip spatial coherence analyzers.
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Strongly Correlated Electrons
Hysteresis without coexistence: disorder-rounded first-order transitions in a van der Waals magnet
Xiaoyu Guo, Abby N. Neill, Christopher M. Pasco et al. (+2 more)
Quenched disorder can profoundly modify phase transitions. In low-dimensional systems, theory predicts that even weak quenched disorder can round the thermodynamic discontinuities associated with a first-order phase transition. Here, we employ time-domain terahertz spectroscopy to investigate the quasi-two-dimensional trimerized kagome van der Waals magnet family Nb$_3$Cl$_{8-x}$Br$_x$ ($x=0$, 1 and 8). We observe the emergence of an additional
phonon branch upon Br substitution, whose spectral weight increases and frequency softens with increasing Br concentration. The temperature
evolution of the
phonon frequencies reveals a clean first-order transition in Nb$_3$Cl$_8$ characterized by macroscopic phase coexistence and thermal hysteresis. In contrast, the transition in the substitutionally disordered compound Nb$_3$Cl$_7$Br retains its hysteresis while exhibiting a substantially broadened transition with no resolvable macroscopic phase coexistence. These observations reveal disorder-induced fragmentation of the transition into locally favored domains instead of well-defined bulk phases separated by stable phase boundaries. The behavior is consistent with the Imry-Wortis and the Aizenman-Wehr scenarios for the effect of quenched disorder in low-dimensional systems, which destabilizes macroscopic phase coexistence and rounds the thermodynamic discontinuities associated with first-order transitions. Thermal hysteresis persists in the disordered compound despite the lack of resolvable coexistence, indicating that the two features often treated as a single hallmark of first-order character arise distinctly and can be separated by disorder. Moreover, our results establish Nb$_3$Cl$_{8-x}$Br$_x$ as a promising platform for investigating the effects of disorder on first-order transitions in low-dimensional systems.
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All authors Xiaoyu Guo, Abby N. Neill, Christopher M. Pasco, Tyrel M. McQueen, N. P. Armitage
Mathematical Physics · Cross-listed from math.CO
Connective constants of Grigorchuk graphs
Geoffrey R. Grimmett
The connective constant $\mu(G)$ of a graph $G$ is the exponential growth rate of the number of self-avoiding walks starting at a given vertex. We prove upper and lower bounds for the connective constants of Cayley graphs $G_\omega$ of a general Grigorchuk group encoded by a sequence $\omega\in\{0,1,2\}^{\Bbb N}$. In particular, $\mu(G_\omega) > \phi$ for any such Cayley graph (subject to a simple condition on $\omega$), where $\phi:= \frac12(1+\sqrt 5)$ is the golden mean. This extends earlier work of the author and Zhongyang Li in "Cubic graphs and the golden mean”, Discrete Math. 343 (2020), article 111638, where it was conjectured that $\mu(G)\ge\phi$ for all infinite, vertex-transitive, cubic graphs. The current work includes an analysis of the proportions of appearances of given label-sequences in the orbital Schreier graphs of general Grigorchuk groups.
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Quantum Physics
Dataflows and Computational Patterns for Hybrid Quantum-Classical Scientific Computing
Ryan Landfield, Jordan J. Winetrout and Michael A. Sandoval
Hybrid
quantum-classical computing has emerged as the dominant paradigm for near-term
quantum applications, yet hybrid workflows are typically described by individual
algorithms rather than their underlying execution behavior. We introduce the
Quantum Execution Locality Framework (QELF), a qualitative framework for characterizing hybrid
quantum-classical workflows according to recurring dataflow structures and
quantum execution locality, the extent to which computation remains resident on the
Quantum Processing Unit (QPU) before host intervention or classical synchronization. From a representative cross-section of applications, QELF identifies five recurring computational patterns with distinct locality characteristics and discusses their implications for communication overhead, workflow organization, and future hybrid computing architectures. By providing a common vocabulary for
reasoning about hybrid workloads, QELF establishes a foundation for future quantitative validation and the co-design of
algorithms, runtime systems, and hybrid computing architectures.
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High Energy Physics (Theory)
Quantum chaos and late-time equipartition of symmetry-resolved Krylov complexity
Jayashish Das, Suman Das, Juan F. Pedraza et al. (+1 more)
We study
symmetry-resolved Krylov complexity in finite-dimensional chaotic
quantum many-body systems. When both the
Hamiltonian and the initial operator commute with a conserved charge, the operator dynamics decomposes into independent
symmetry sectors, each with its own Krylov chain. We show that, after saturation, the unresolved Krylov complexity is additive over
symmetry sectors. In the absence of additional Liouvillian degeneracies, the late-time contribution of a sector with
Hilbert-space dimension $d_q$ is controlled by $d_q(d_q-1)$, leading to a dimension-weighted equipartition that approaches the simple large-sector scaling $d_q^2/\sum_{q'}d_{q'}^2$. This late-time rule differs from the early-time weighted-average discussed in the literature and is governed instead by the dimensions of the accessible operator spaces. We support the analytic prediction with numerical studies of the real and complex SYK models, a chaotic bosonic
spin model, and the mixed-field Ising chain. Our results show that resolving exact
symmetries is essential for interpreting the saturation value of Krylov complexity as a diagnostic of chaotic operator growth.
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All authors Jayashish Das, Suman Das, Juan F. Pedraza, Le-Chen Qu
Quantum Physics
Hyperon-antihyperon system in electron-positron annihilation as quantum probes for temperature estimation with local and global dephasing
Anass Hminat, Abdallah Slaoui, Rachid Ahl Laamara et al. (+1 more)
We investigate
quantum thermometry in Ohmic-type reservoirs using two-
qubit probes within an exactly solvable pure-dephasing framework. By analyzing the individual variance associated with temperature estimation, we identify optimal regimes governed by the Ohmicity parameter $s$, the deviation angle $\theta$, and the decay coefficients $\alpha$ and $\beta$, thereby determining the conditions that minimize estimation errors. The
Quantum Fisher Information (QFI) exhibits pronounced maxima at finite interaction times, especially in sub-Ohmic and Ohmic environments at low temperatures, whereas super-Ohmic reservoirs flatten the QFI peak and shift the optimal sensitivity toward higher temperatures. Consistently, the
quantum signal-to-noise ratio (QSNR) is suppressed at low temperatures, increases with thermal excitation, and saturates in the high-temperature regime, where the influence of spectral details becomes negligible. A comparative study of mutual and local estimation strategies shows that common-bath configurations, particularly for $\Sigma^+$ and $\Sigma^0$ probes, outperform local baths at short interaction times due to bath-induced correlations, while local environments become advantageous at longer times. The analysis further reveals finite optimal values of both the interaction time $t_{\rm opt}$ and the temperature $T_{\rm opt}$, as well as a strong reduction of the variance with increasing measurement number in the low-temperature regime. In addition, our study of hyperon-antihyperon channels ($\Lambda$, $\Sigma^+$, $\Sigma^0$, $\Xi^-$, $\Xi^0$) shows that
entanglement and
quantum discord remain remarkably robust over broad angular domains, whereas steering and Bell nonlocality are confined to narrower regions. Overall, the interplay between spectral structure, particle-dependent parameters, and estimation strategy provides valuable ...
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All authors Anass Hminat, Abdallah Slaoui, Rachid Ahl Laamara, Hichem Eleuch
Superconductivity
Self-calibrating thermal interferometry of vortex parity in a two-dimensional chiral superconductor
Kumar Ghosh
A
chiral superconductor carries
chiral Majorana modes along its boundary, and the integer that counts them fixes everything that follows, yet that integer has never been measured together with a local parity observable on one object. Proximitized one-dimensional wires read
fermion parity rapidly but diagnose bulk
topology through a separate protocol. Here we show that a reconfigurable domain wall between regions of opposite Chern number in an intrinsic two-dimensional
chiral superconductor performs both functions. Opened to its contacts the wall is a ballistic channel whose quantized thermal conductance counts its Majorana modes; closed, the same wall is a Fabry–Pérot resonator whose spectrum shifts by half a level spacing when the parity of the enclosed
vortices changes, giving a two-level heat conductance. We derive the exact transmission, the elastic heat full counting statistics, and a
theorem showing that linear-response heat scattering of a fixed quadratic problem resolves
vortex parity but not the fusion channel of well-separated cores. An outside
vortex hybridized with the wall is an intrinsic false positive; temperature, geometry and a finite-bias mean–noise test separates it. Rhombohedral-
graphene parameters place submicron loops in the resolved regime at millikelvin temperatures, where
chiral-domain reconfiguration and noise thermometry are both established.
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Fluid Dynamics
Effect of Microscale Turbulent Structures Dynamics on Forced Convection in Turbulent Porous Media Flow
Ching-Wei Huang, Vishal Srikanth and Andrey V. Kuznetsov
The influence of microscale flow structures (smaller than the pore size) on turbulent heat transfer in porous media has not been yet investigated. The goal of this study is to determine the influence of the micro-
vortices on convection heat transfer in turbulent porous media flow. Turbulent flow in a homogeneous porous medium was investigated using Large Eddy Simulation (LES) at a Reynolds number of 300. We observed that the convection heat transfer characteristics are dependent on whether the micro-
vortices are attached or detached from the surface of the obstacle. There is a spectral correlation between the Nusselt number and the pressure instabilities due to
vortex shedding. A secondary flow instability occurs due to high pressure regions forming periodically near the converging pathway between obstacles. This causes local adverse pressure gradient, affecting the flow velocity and convection heat transfer. This study has been performed for obstacles with shapes of square and circular cylinders at porosities of 0.50 and 0.87. Understanding the dominant modes that affect convection heat transfer can aid in finding an optimum geometry for the porous medium.
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Materials Science
Cumulative X-ray Damage in Bismuth Selenide Examined by Simultaneous TXM and XRD
Sophie E Parsons, Bernard Kozioziemski, Daewoong Nam et al. (+21 more)
Bismuth selenide (Bi2Se3) is a topological
insulator with potential applications in thermoelectrics, spintronics, and optoelectronics. However, its response to radiation remains poorly understood. We investigate cumulative X-ray damage in Bi2Se3 using simultane- ous transmission X-ray microscopy (TXM) and X-ray diffraction (XRD) at the Pohang Accelerator Laboratory X-Ray Free Electron
Laser (PAL-XFEL) over 27,000 successive pulses. We observe distinct damage mechanisms: rapid hole formation via vaporization within 100 pulses, followed by slower grain refinement and material sputtering over thousands of thermal cycles. Williamson-
Hall analysis reveals a progressive transformation from single-
crystal to nanocrystalline structure, with grain sizes decreasing from mi- cron to nanometer scale. Finite-element modeling confirms that X-rays penetrate 13.47 {\mu}m, driving local temperatures above 1600 K with subsequent cooling between pulses. Scanning electron microscopy identifies three characteristic morphologies correspond- ing to different thermal histories: sputter streaks, prismatic
crystals, and disordered microcrystals. Our results demonstrate that grain-boundary formation creates a feedback mechanism that accelerates damage in later pulses. This work establishes a method- ology for studying radiation damage across multiple length scales and provides insight into topological
insulator stability under extreme conditions
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All authors Sophie E Parsons, Bernard Kozioziemski, Daewoong Nam, Eric Folsom, Can Yildirim, Sean Breckling, Sungwook Choi, Eric C. Galtier, Arnulfo Gonzalez, Deja Dominguez, Emlyn Frederick, Marylesa M. Howard, Sara Jessica Irvine, Kento Katagiri, Sangsoo Kim, Seonghan Kim, Sunam Kim, Stephan Kuschel, R. Stewart McWilliams, Norimasa Ozaki, Alison M. Saunders, Hyunjung Kim, Jon Eggert, Leora Dresselhaus-Marais
Mathematical Physics · Cross-listed from math.AP
The Liquid Drop Model with a Yukawa Potential: Existence of Minimizers and Sharp Stability of the Ball
Lia Bronsard, Kenneth DeMason and Ihsan Topaloglu
We study a long-range perturbation of the perimeter functional by a nonlocal repulsive term defined through the Yukawa kernel, minimized under a volume constraint. Because the kernel decays exponentially, the competition between surface tension and repulsion is governed by two independent quantities, the screening rate and the volume. Specifically we prove that (i) above an explicit critical screening rate, minimizers exist at every volume, whereas earlier work required the volume to be large; (ii) below an explicit volume threshold minimizers exist for every screening rate; (iii) at small volume, and uniformly in the screening rate, the ball is the unique minimizer up to translation; and (iv) there exists a sharp volume threshold, depending on the screening rate, for the ball to be a stable volume-constrained critical point. The threshold is given in closed form for every screening rate and reduces to the known unscreened value when $\alpha=0$. Our proofs overcome new technical changes due to the lack of homogeneity in the Yukawa kernel.
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Solar and Stellar Astrophysics
ALMA high resolution observations of Betelgeuse: Persistent structure spanning the inner atmosphere
W.R.F. Dent, A.M.S. Richards, G.M. Harper et al. (+2 more)
The extended atmosphere of red supergiants (RSGs) forms an important link in the process of mass loss and the subsequent enrichment of the interstellar medium. Large-scale convection is thought to play a significant role, which is likely to result in irregularities in the surface. High resolution, high contrast sub-mm images of Betelgeuse - one of the closest RSGs - are used to probe the structure and temporal stability of the inner 1-2$R_\star$ of its atmosphere. Using ALMA in the longest baseline configuration, continuum emission and lines of SiO and CO and their isotopomers were observed at $\lambda$0.6-1.4mm, giving beamwidths down to 7mas at the shortest wavelengths. These were compared with a similar observation taken at 0.9mm approximately 7 years earlier. The observed continuum emission arises mostly from an optically-thick mm/sub-mm photosphere of radius 1.1-1.3$R_\star$ with a relatively constant temperature of $\sim$2300K, but with two hotter patches to the NE and SW. The brightest of these has a temperature enhancement of $\sim$800K, and its location and intensity appears relatively unchanged since the 2015 observation. The sub-mm photosphere shows deviations of up to $\pm$ 6% in radius, with weaker continuum extending out to $\sim$2.5$R_\star$ - similar to the extent of clumpy emission in SiO and CO. The hot regions of gas and deviations from radial
symmetry are thought to be associated with active shocks driven by underlying convective
cells, although their lifetimes appear longer than model predictions. They lie near the proposed poles of the
star, which might suggest enhanced and relatively stable polar convection. The present data show no clear evidence for
stellar rotation in the extended line emission or absorption against the photosphere, although the structure of the gas emission has changed significantly since 2015.
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All authors W.R.F. Dent, A.M.S. Richards, G.M. Harper, L.D. Matthews, E. O'Gorman
Instrumentation and Methods for Astrophysics
Design, assembly, and initial test results of a cryostat for holographic characterization of microwave telescopes
Jon E. Gudmundsson, Miranda Eiben, Thomas J.L.J. Gascard et al. (+1 more)
We describe the design, fabrication, assembly, and room-temperature
vacuum qualification of a 1.4-m long cylindrical cryostat developed for
holographic testing of cryogenic microwave
telescope optics. The system consists of a welded 6061-aluminum
vacuum vessel containing nested 45- and 4-K aluminum radiation shields, cooled by a two-stage pulse-tube cryocooler through commercial OFHC copper flexible thermal straps. The intermediate 45-K stage intercepts radiative, conductive, and wiring heat loads from room temperature, while the 4-K stage defines the volume used for optical testing. The cryostat includes a 38-cm aperture for a microwave-transparent
vacuum window and is sized to accommodate full-scale optical assemblies relevant to
cosmic microwave background instrumentation. We summarize the cryostat architecture, lightweighted radiation shields, G-10 support flexures, welded
vacuum-vessel fabrication, and room-temperature leak-checking campaign. Iterative helium leak checking and weld repair reduced the observed leak rate in the cryostat by over three orders of magnitude.
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All authors Jon E. Gudmundsson, Miranda Eiben, Thomas J.L.J. Gascard, Eve M. Vavagiakis
Quantum Physics
Multipolar Light-Matter Hamiltonians in Symmetry-Breaking Photonic Vacuums
Liu Yang, Jiadu Lin and Qing-Dong Jiang
We show that the conventional multipolar
Hamiltonian is qualitatively modified when the photonic
vacuum breaks inversion or time-reversal
symmetry. By explicitly applying the Power-Zienau-Woolley transformation, we derive the resulting multipolar
Hamiltonians for two idealized
chiral photonic environments: a spatial-
chiral vacuum, which breaks inversion
symmetry, and a temporal-
chiral vacuum, which breaks time-reversal
symmetry. In the spatial-
chiral case, the transformation generates an inversion-breaking self-energy, whereas in the temporal-
chiral case it produces an additional Zeeman-like energy. Using a trapped hydrogen-like atom and a charged harmonic oscillator in cavities as minimal examples, we show that these
symmetry-dependent terms lead to characteristic spectral shifts. Our work provides a general framework for describing light-matter interactions in
chiral quantum electrodynamics and identifying the associated
symmetry-dependent effects on cavity-embedded atoms, molecules, and
quantum materials.
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Quantum Physics
Glassy dynamics with softened kinetic constraints on a noisy quantum computer
Marcel Cech, Igor Lesanovsky and Federico Carollo
Mid-
circuit measurements provide direct access to trajectory-level observables, revealing dynamical structures in many-body systems that are invisible in ensemble-averaged quantities. We exploit this capability to realize and study an instance of the Floquet-East model on a superconducting
quantum processor. Here, the combination of mid-
circuit measurements, kinetically constrained
unitary operations and hardware noise gives rise to intricate many-body phenomena. Analyzing trajectories obtained from temporally and spatially resolved mid-
circuit measurements, we identify dynamical heterogeneity — a hallmark of glassy dynamics. We quantify this emergent behavior by studying the probability of finding inactive space-time regions of a given size. This quantity displays a crossover from area- to perimeter-dominated scaling, which is a characteristic property of glasses and is associated with the proximity to a dynamical first-order phase transition. Our results establish current noisy intermediate-scale
quantum devices as scalable testbeds for investigating correlated many-body phenomena at the level of measurement trajectories.
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General Relativity and Quantum Cosmology
Breakdown of Hydrodynamic Universality in Neutron Star Oscillations
Gabriel S. Denicol, Amanda Guerrieri, João V. M. Muniz et al. (+2 more)
Hydrodynamic universality refers to the property that different formulations of relativistic dissipative hydrodynamics yield identical predictions in the asymptotic long-wavelength regime. We show that
neutron-
star oscillations need not reach this regime. Because the finite
stellar radius limits the accessible wavelengths and causality imposes a lower bound on microscopic relaxation times, the separation between microscopic and macroscopic scales can become insufficient for hydrodynamic universality to emerge. Comparing linear oscillations in relativistic Navier–Stokes and Israel–Stewart theories, we find that realistic bulk viscosities can produce sizeable modifications of the oscillation spectrum, even at the longest wavelengths. These results identify
neutron-
star oscillations as a direct probe of microscopic nonequilibrium dynamics beyond the leading hydrodynamic description.
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All authors Gabriel S. Denicol, Amanda Guerrieri, João V. M. Muniz, Gabriel S. Rocha, Raissa F. P. Mendes
Quantum Physics
Strongly coupled atom-cavity systems under boundary modulation: simulating gravitational-wave effects
Patryk Michalski, Jerzy Paczos, Navdeep Arya et al. (+1 more)
One of the proposed platforms in which both
quantum and general relativistic effects can become observable is an atom interacting with the electromagnetic field in a gravitational-wave background. The periodic modulation of field modes induced by variations of the spacetime metric modifies the atomic emission spectrum. Notably, the temporal modulation of the mode-frequency induced by a plane gravitational wave can be simulated through modulated boundary conditions, such as moving cavity mirrors. We analyze the impact of this modulation on atom-field interactions in the strong atom-cavity coupling regime, where Rabi oscillations occur. We show analytically that the modulation is resonantly enhanced, leading to measurable imprints in the atomic transition probability. This establishes a realistic and experimentally accessible platform for probing analogue general relativistic effects in
quantum optical systems.
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All authors Patryk Michalski, Jerzy Paczos, Navdeep Arya, Magdalena Zych
High Energy Astrophysical Phenomena
The intrinsic luminosity-decay correlation in subsamples of GRB X-ray afterglows
S. P. R. Shilling, S. R. Oates, J. L. Racusin et al. (+6 more)
The intrinsic luminosity-decay correlation in gamma-ray burst (GRB) afterglows, between the early-time luminosity and the average rate of decay past this time, has previously been observed in the
radio, optical/UV, X-ray and GeV wavebands and quantitatively shows that more luminous afterglows tend to have higher average rates of decay. We have compiled an updated sample of 427 X-ray afterglows with measured
redshifts, observed with Swift/XRT over 20 years. For each GRB, we measure the luminosity at 200 seconds in the rest frame, $L_{\mathrm{X,200s}}$, and the average rate of decay from this time, $\alpha_{X,>200s}$. We find these parameters are correlated with a Spearman's rank coefficient ($R_\mathrm{sp}$) of $0.54\pm0.04$ at a significance of $\geq3\sigma$ and a linear regression slope of $0.18\pm0.02$. We separate our sample into subsamples, including 395 long GRBs (LGRBs) and 32 short GRBs (SGRBs) and find evidence of the $L_{\mathrm{X,200s}}$-$\alpha_{X,>200s}$ correlation at a significance of $\geq3\sigma$ in LGRBs but not in SGRBs, consistent with previous studies. In a subsample of 102 LGRBs with well-sampled light curves and late end times, we find that scatter in the correlation is significantly reduced and the strength increases to $R_\mathrm{sp}=0.80\pm0.04$ whilst the slope remains consistent with the full sample. We discuss our results and, briefly, their potential implications on constraining the cause of the correlation. Possible causes include
geometric effects due to the angle between the observer and the jet-axis, or some mechanism that regulates the rate at which energy is released by the GRB central engine.
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All authors S. P. R. Shilling, S. R. Oates, J. L. Racusin, B. Cenko, R. Gupta, P. Nuessle, M. Smith, G. P. Lamb, C. Turnbull
High Energy Physics (Theory)
Deep neural networks as lattice gauge theories
Ro Jefferson and Shradha Ramakrishnan
We modify the NN/QFT duality [1] to incorporate the layerwise permutation
symmetry of the network, resulting in a $(0\!+\!1)$-dimensional
lattice gauge theory, in which each layer of $N$
neurons acts as an $N$-component
lattice site, and the weight
matrices play the role of gauge fields living on the links. In this framework, we compute the tree-level
neuron-
neuron propagator which describes the
evolution of layer variance in the network, and develop the Feynman diagram machinery to compute interactions in the perturbative expansion in $1/N$. In particular, we obtain a recursive expression for all corrections to the exact propagator at $O(1)$, representing statistical fluctuations in the ensemble of networks, including infinitely-many loop diagrams mediating the interactions from previous layers. We also present a preliminary analysis of
neuron scattering amplitudes that contribute order-by-order in $1/N$, which provides a field-theoretic framework for studying higher-point correlations, and by extension information propagation, in deep networks. We remark on some interesting directions for future work at the intersection of neural networks and
quantum field theory.
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Lattice Field Theory
QCD crossover temperature and curvature coefficient from unbiased exponential resummation at physical quark masses in (2+1)-flavor lattice QCD
Sabarnya Mitra
We present the first application of the unbiased exponential resummation method to the determination of the QCD pseudocritical temperature $T_{\rm pc}$ at vanishing
baryon chemical potential $\mu_B$. By reconstructing the finite-density
baryon number susceptibility $\chi_2^B$, we define two thermal-derivative observables whose peak positions yield $T_{\rm pc}^T=160.2(4)(3)$ MeV and $T_{\rm pc}^C=158.1(5)(3)$ MeV. We also show that the pseudocritical temperature, $T_{\rm pc}^\chi$ obtained from the peak of the fourth-order
baryon number susceptibility $\chi_4^B$ is consistent with these determinations and with previous
lattice-QCD results based on Taylor expansions \cite{Bollweg:2022Pade}. Further, we demonstrate that scaling relations \cite{Bollweg:2022fqq} between $\chi_4^B$ and the thermal derivatives of $\chi_2^B$ yield mutually consistent estimates of the leading second order
curvature coefficient $\kappa_2^B$ at the corresponding pseudocritical temperatures. A direct analysis of the $\mu_B$ dependence of the pseudocritical temperatures provides an independent but substantially less constrained determination of the
curvature, which remains statistically consistent with the scaling-based estimates. These results demonstrate the consistency of unbiased exponential resummation with the expected scaling behavior and establish it as a complementary approach for probing the QCD crossover at small finite
baryon density.
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Earth and Planetary Astrophysics
Substructure evolution from protoplanetary to debris disks driven by mutually gravitating planetesimals and implications on Kepler resonances and free-floating planets
Yinuo Han, Konstantin Batygin and Fei Dai
Motivated by recent observations suggesting rings found in debris disks are wider than those in protoplanetary disks, we consider a picture in which planetesimals formed in radially narrow
dust traps radially diffuse into debris rings via mutual scattering. Under this picture, evolving the fractional widths ($\Delta r/r$) of resolved debris rings back to a few Myr according to the theoretical $t^{1/5}$ evolutionary trajectory reproduces the protoplanetary ring distribution. We inferred the product of the ring mass and individual planetesimal mass required to reach the observed debris ring widths at their ages, finding that $M_\mathrm{disk}\times m$ ranges from $10^{-3}$ to $10^{3} \, M_\oplus^2$. The distribution of $M_\mathrm{disk} \times m$ appears to correlate with the
stellar mass, peaking at 1.5 to 2 $M_\odot$, which resembles the
stellar mass dependence of the
giant exoplanet occurrence rate. The population of resolved debris rings lie close to the $\Delta r / r = 10 \, h$ equipartition relation expected of a planetesimal ring that formed narrow, with typical resolved debris disks still expected to be broadening radially and vertically at present. If sufficiently massive ($\sim$10 $M_\oplus$), this radial broadening can send a few Mercurys to the terrestrial region within 10 Myr, making debris disks a plausible source of planetesimals disrupting resonant chains among Kepler
planets. Within Gyr timescales, outer planetesimal belts can also eject $\sim$1% of their mass into interstellar space if they consist of Moon-sized bodies or above, suggesting that the slow and steady intrinsic
evolution of massive debris disks could contribute to the interstellar free-floating population of terrestrial-
planet-sized bodies.
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Earth and Planetary Astrophysics
The Effects of M Star Age Dependent Ultraviolet Emission on Detecting and Interpreting Exoplanet Biosignatures
C. Evan Davis, Victoria S. Meadows, Evgenya L. Shkolnik et al. (+5 more)
Given their abundance and observational advantages, M
stars will arguably be the best candidates for characterizing and searching for biosignatures on terrestrial
exoplanets in the near future. However, photochemistry that can suppress or enhance key biosignature molecules in planetary atmospheres is primarily driven by UV flux from the host M
star, which is influenced by
stellar activity that decreases with age. Here, we simulate Pre-Industrial Earth-like and Archean Earth-like atmospheres around M4 and M8
stars from 650 Myr to 5 Gyr old. We find that our Pre-Industrial Earth atmospheres around 5 Gyr M
stars have up to ten times more CH$_4$ than those around 650 Myr M
stars, producing 68% stronger methane bands in NIR transit spectroscopy. Additionally, photochemical shielding from O$_2$ in our Pre-Industrial Earth atmospheres reduces the impact UV-driven photochemistry on composition, while the Archean Earth exhibits larger compositional changes due to weaker shielding from CO$_2$. Lastly, enhanced CO$_2$ photolysis, driven by the strong net UV flux and high Far/Near-UV ratios of 650 Myr and 1 Gyr M
stars, cause our Archean Earth-like
planets to produce up to 5.4 dex more O$_3$ than when around 5 Gyr M
stars. The excess O$_3$ causes the Archean Earth to become half as reflective in the 0.2-0.3 $\mathrm{\mu}$m Hartley band feature in ultraviolet reflectance spectroscopy, which the Habitable Worlds Observatory may be sensitive to. Without the context of the
star's real-time, age-dependent UV radiation, this O$_3$ feature could be misinterpreted as a proxy for low, biogenic O$_2$.
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All authors C. Evan Davis, Victoria S. Meadows, Evgenya L. Shkolnik, Andrew P. Lincowski, Sarah Peacock, R. O. Parke Loyd, Adam C. Schneider, Travis Barman
High Energy Physics (Theory)
Inflationary Bispectra and IR Physics from Quantum Simulators
Matthias Thomas Nowinski and Ivo Sachs
Bose-Einstein condensates have been used successfully as
quantum simulators for early-universe particle production. Here we extend this analogy to the interacting theory. To this end, we compute the leading interaction terms expected in a general experimental setup that determine the 3-point correlations. We apply them to cosmologically motivated expanding model universes, but also periodically oscillating ones. While expanding scale factors do not necessarily lead to easily observable signatures due to experimental constraints on the realizable scale factor, periodically driven ones produce resonant correlators that grow linearly over time and lend themselves well to experimental detection. One direct application of this analysis is the experimental study of late-time infrared divergencies often discussed in the context of massless scalars in de Sitter space.
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Astrophysics of Galaxies
Serendipitous discovery of an almost-dark galaxy in the Virgo Cluster
Minh Ngoc Le, Ignacio Trujillo, Sergio Guerra Arencibia et al. (+9 more)
Analogues of extreme Local Group
galaxies with very low surface brightnesses and large effective radii must exist elsewhere, still hidden due to current detection limits. We report the serendipitous discovery of the low-mass almost-dark
galaxy TTT J1237327+143535 in the Virgo Cluster, observed using the Two-meter Twin
Telescope at the Teide Observatory. TTT J1237327+143535 has a central surface brightness of $27.9 \pm 0.2 \, \mathrm{mag\, arcsec}^{-2}$ in the $g'$ band, an effective radius of $0.9 \pm 0.1 \mathrm{kpc}$, and a total
stellar mass of $(2.2 \pm 0.4) \times 10^6 \mathrm{M_\odot}$. Its effective radius and absolute magnitude are similar to those of
galaxies And XXI and And XXIII. The discovery of this extremely low-surface-brightness, extended, low-mass
galaxy suggests the existence of a significant population of almost-dark
galaxies in the Virgo Cluster. An in-depth analysis of the Next Generation Virgo Cluster Survey, as well as upcoming Rubin data releases and the 10-year Rubin Legacy Survey of Space and Time, is expected to reveal large samples of this extreme
galaxy population, which will offer insights into
galaxy formation in extreme conditions.
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All authors Minh Ngoc Le, Ignacio Trujillo, Sergio Guerra Arencibia, Ignacio Ruiz Cejudo, Junais, Mireia Montes, Johan H. Knapen, Željko Ivezić, Michael H.F. Wilkinson, Reynier Peletier, Miquel Serra-Ricart, Miguel R. Alarcon
Quantum Physics
Statistical Mechanics of Non-Abelian Learnability Transitions
Ruochen Ma and Romain Vasseur
Monitored many-body
quantum systems can undergo sharp learnability transitions characterized by how much information can be learned by the observer. When the dynamics conserves a non-Abelian charge, such as an $SU(2)$
spin, understanding how the observer learns the total charge remains an outstanding problem. Unlike the Abelian case, where charge measurements on distinct sites commute, the $SU(2)$-symmetric readouts are noncommuting fusion measurements, making learning a genuinely
quantum inference problem. In this work, we propose a theory of $1+1d$ monitored
quantum dynamics with $SU(2)$
symmetry, and show that it can be described by an effective replicated loop model comprised of a replica-pairing field and a diffusive ($z=2$) background sector that carries the $SU(2)$ charge and remains gapless throughout the phase diagram. Our theory predicts that the "
spin-sharpening” and
entanglement transitions coincide as a single transition. Ordering of the pairing field produces volume-law
entanglement and hides the background sector from measurements, leading to a learning time of $t\sim L^{3}$ for the total
spin. When the pairing field disorders, the background sector alone gives logarithmic
entanglement and a diffusive learning time $t\sim L^{2}$. Our analysis is controlled by a large-loop-fugacity expansion.
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High Energy Physics (Theory)
Black Holes, the Bethe Ansatz, and Elliptic Calogero–Moser Systems
Marco Fazzi and Kuba Krawczyk
We define a map from solutions of the Bethe Ansatz equations (BAEs) of four-dimensional $\mathcal{N}=4$ super-Yang–Mills with arbitrary semisimple gauge
algebra $\mathfrak{g}$ to extrema and poles of the potential of the untwisted
elliptic Calogero–Moser system of type $\mathfrak{g}$. We
conjecture the map to be a bijection on the preimage of the Calogero–Moser extrema, and show that it intertwines the
symmetries of the two systems, both the gauge ones (
torus, Weyl and center invariance) and a $\mathrm{PSL}(2,\mathbb{Z})$ action, so that solutions on both sides organize into orbits, each BAE orbit mapping onto a single orbit of Calogero–Moser extrema or poles. That the system produced is the untwisted one has a consequence: the conjectured correspondence between BAE solutions and
vacua of the $\mathcal{N}=1^\ast$ deformation of $\mathcal{N}=4$ on $\mathbb{R}^{3,1}$, which are extrema of the twisted system, cannot extend to non-simply-laced $\mathfrak{g}$. It also fails within the simply-laced cases, though not for $\mathfrak{su}(N)$: we exhibit an $\mathfrak{so}(8)$ solution that flows to a pole of the Calogero–Moser potential rather than to an extremum, and so has no $\mathcal{N}=1^\ast$ counterpart. We illustrate the map in detail for every rank-two $\mathfrak{g}$, classical and exceptional alike, and use these cases as evidence for the
conjecture.
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High Energy Physics (Theory)
The EEC-Hedron: Positivity Bounds on Energy Correlators
Bianka Meçaj, Ian Moult, Hidde Stoffels et al. (+2 more)
We study the constraints placed by energy positivity on general
unitary quantum field theories. We show that the coefficients in the partial wave expansion of energy-energy correlators all must lie within a bounded region of parameter space, which we call the “EEC-hedron”. For the particular case of conformal field theories, these positivity constraints on energy correlators lead to bounds on the allowed values of coefficients in the operator product expansion. We demonstrate this approach in the 3d Ising and $O(2)$ CFTs, deriving new bounds on OPE coefficients in both theories.
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All authors Bianka Meçaj, Ian Moult, Hidde Stoffels, Matthew T. Walters, Yuan Xin