Mesoscale and Nanoscale Physics
Complete kinematic null for local kinetic dissipation in a sixfold-driven electron fluid
P. Shubham Parashar
We identify a complete kinematic null in a two-dimensional electron fluid driven by a sixfold boundary pattern. In the $U_3^\pm$ channel of $D_{12}$, device
symmetry excludes both the vector representation $R_1$ and the full first-gradient tensor $R_1\otimes R_1$. Hence at the
symmetry-fixed center $\mathbf{j}(0)=0$ and $\partial_i j_j(0)=0$, so every local quadratic dissipative form built from the modeled charge/momentum field through first gradient order vanishes independently of the constitutive coefficients. In an $O(2)$-isotropic angular-harmonic kinetic model the first allowed local sector is $m=3$. For $\nu q^2/\gamma_3\ll1$, its heating is set by the previously derived coefficient $\kappa_4=v_F^4/(16\gamma_2^2\gamma_3)$. An explicit incompressible Stokes disk realizes a nonzero center signal, and a finite-moment kinetic boundary-value solution approaches the corresponding local
benchmark. Within the local, fixed-current momentum-conserving Stokes regime, the normalized
magnetic response can then be fitted for effective $\gamma_3$ and $\gamma_2$. Thus the sixfold drive creates a measurement point where ordinary local charge/momentum hydrodynamic dissipation is absent while a kinetic mode remains finite.
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Strongly Correlated Electrons
Cell Natural Orbitals in Interacting Topological Bands
Nishchhal Verma, Harshitra Mahalingam, Daniel Muñoz-Segovia et al. (+1 more)
Topological bands exhibit obstruction to exponentially localized and symmetric Wannier functions, challenging the standard paradigm of representing projected interactions in terms of local orbitals with finite range. To faithfully capture the form factors and
quantum geometry of topological bands we introduce a singular-value decomposition of the band-projected density form factors, enabling a geometry-based truncation scheme of the
Hilbert space, exposing an intrinsic hierarchy on band-projected interactions that is determined by the underlying wavefunctions. This decomposition is most naturally described in terms of
Cell Natural Orbitals (CNOs), as the eigenstates of the unit-
cell reduced one-particle density
matrix, whose occupation provide a measure of the minimal orbital complexity required to faithfully represent the band wavefunctions overlaps. The CNO decomposition identifies systematically the minimal number of local orbitals needed to reproduce short-ranged interactions while resolving the hierarchy of interaction strengths across CNO channels. Applied to magic-angle twisted
bilayer graphene in the
chiral limit, we find that the dominant CNO is centered at the AA site, resembling the $f$-
fermion of the heavy-
fermion model. The subdominant CNO channels carry progressively weaker interaction
matrix elements, allowing them to be treated at the static mean-field level, while the dominant channel requires a dynamical self-energy. The formalism illustrates how variations of charge density within the unit
cell generate momentum dependence in the CNO envelope function and, consequently, dispersion in the single-particle spectral function. More broadly, our results establish CNOs as a geometry-informed bridge between band
topology and real-space correlations, providing a systematic framework for analyzing interactions and emergent phases in
quantum materials.
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All authors Nishchhal Verma, Harshitra Mahalingam, Daniel Muñoz-Segovia, Raquel Queiroz
Cosmology and Nongalactic Astrophysics
Realization Variance of Gravitational Wave Background Anisotropies from Shot Noise for Pulsar Timing Arrays
Meng-Xiang Lin, Adam Lidz and Chung-Pei Ma
Shot-noise anisotropies in the nHz gravitational wave background (GWB) are a promising target for
pulsar timing arrays (PTAs). If the nHz GWB is sourced by merging supermassive black hole binaries (SMBHBs), as current evidence suggests, the shot-noise signal is expected to be large, potentially of order unity at observing frequencies of $f \sim 1 \, \mathrm{yr}^{-1}$. In this regime, the signal is dominated by rare bright binaries, and Poisson fluctuations in the discrete SMBHB population produce significant spatial anisotropies. Here, we use Monte Carlo simulations to model the realization-to-realization scatter in the shot-noise, sampling from empirically calibrated models of the SMBHB source populations. We find that the probability distribution of shot-noise amplitudes is broad, spanning a factor of $\sim 50$ (95% interval) at fixed frequency, with a long tail towards high amplitudes. The most probable and median amplitudes lie significantly below the ensemble means by factors of $\sim 2-3$, implying that the shot-noise in typical realizations is smaller than the mean. The ensemble-averaged shot-noise also differs from simple estimates based on moments of the strain, $\langle h^4 \rangle/\langle h^2 \rangle^2$, because the average of a ratio is not equal to the ratio of the averages (i.e., $\langle X/Y \rangle \ne \langle X \rangle/\langle Y \rangle$). This difference is a factor of $\sim 3$ at $f = 0.1 \, \rm{yr}^{-1}$, growing to larger than two orders of magnitude by $f \sim 1 \, \rm{yr}^{-1}$, where the GWB is dominated by low abundance, high-strain sources. Shot-noise nevertheless provides a powerful diagnostic for understanding the GWB and SMBHB populations; interpreting PTA measurements, however, requires modeling its full probability distribution.
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Quantum Physics
A Quantum Coherence Microscope in the Hubbard Regime
Lin Su, Michal Szurek, Alec Douglas et al. (+2 more)
Quantum coherence underlies collective
quantum phenomena and emerging
quantum technologies.
Quantum gas microscopes have transformed
quantum simulation by providing projective snapshots of many-body states with single-atom resolution, but spatially resolved measurements of off-diagonal correlations have remained elusive. Here, using the Talbot effect, we introduce a
quantum coherence microscope that maps off-diagonal correlations onto site-resolved density signals with near-single-site resolution. We use this technique to locally probe the superfluid-Mott transition in a layer of a three-dimensional optical
lattice and to measure coherence beyond nearest neighbors in an engineered potential landscape. By mapping off-diagonal correlations onto density signals through controlled Talbot
evolution, this work opens new possibilities for accessing observables beyond the density basis through tailored matter-wave
evolution and recapture.
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All authors Lin Su, Michal Szurek, Alec Douglas, Ceren B. Dag, Markus Greiner
High Energy Physics (Theory)
The quadratic growth of Krylov spread complexity in the BTZ black hole
Aranya Bhattacharya, Mario Flory, Michal P. Heller et al. (+2 more)
The boundary quantity that captures the growth of black-hole interiors quantified by
holographic complexity remains unknown beyond 2d dilaton
gravity. We provide a critical analysis of a partition-function construction of Krylov spread complexity for thermofield-double states that provides a dimension-independent boundary reconstruction from semiclassical
holographic partition functions, while developing the present dynamical and bulk construction for the BTZ saddle. In the double-scaled Sachdev-Ye-Kitaev model, where exact and semiclassical results can be compared, we show that the classical limit is reliable only when taken after the complexity has been reconstructed; taking this limit at the level of individual Lanczos coefficients discards essential information. Applying the construction to a large-central-charge two-dimensional conformal field theory above the Hawking-Page temperature dual to a Bañados-Teitelboim-Zanelli black hole, we find an intermediate departure from early-time quadratic growth followed by behavior compatible with a return toward asymptotically quadratic growth, rather than the linear late-time behavior of the volume and the standard finite-functional complexity = anything class. We then match this boundary behavior to a generalized complexity = anything bulk object built from an infinite series of extrinsic-
curvature invariants. The construction provides a systematic route from black-hole thermodynamics to Krylov dynamics and can naturally be extended to higher-dimensional
holographic black holes.
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All authors Aranya Bhattacharya, Mario Flory, Michal P. Heller, Emiliano Rizza, Tim Schuhmann
Solar and Stellar Astrophysics
IPA: Morphology and Kinematics of Molecular Hydrogen Winds in Five Young Protostars across the Mass Spectrum Observed with JWST
Himanshu Tyagi, P. Manoj, Mayank Narang et al. (+29 more)
Molecular winds may play a key role in governing angular momentum transport and
accretion during the early
evolution of protostars. We present the morphology and kinematic properties of the H$_2$ emission in five young, envelope-dominated, protostars across a broad bolometric luminosity range, from 0.2 to $10^4~L_{\odot}$, observed with the NIRSpec/IFU and MIRI/MRS onboard JWST as part of the Investigating Protostellar
Accretion (IPA) program. A rich set of pure rotational lines of H$_2$, up to $v=0-0$ S(18), and a few ro-vibrational lines are detected in the winds, revealing bipolar structures. The H$_2$ lines show a stratified/onion-like structure morphologically and kinematically, where the lines with higher $E_{\rm up}$ show a higher degree of collimation and higher velocities. Additionally, the wind velocity scales with the $L_{\rm bol}$ of the host protostellar system. In 4 out of 5 protostars, H$_2$ emission fills the
outflow cavity without showing pronounced limb brightening. We also report a tentative detection of H$_2$ wind rotation in IRAS 16253, which suggests a launch radius of $\sim4$ au and the
magnetic lever arm parameter of $\sim5-10$. Taken together, these properties of the H$_2$ winds can be explained by the magnetohydrodynamic disk wind models. We detect a collimated, high-velocity H$_2$ jet toward HOPS 370, which is more evolved than the extremely young source HH 211, but is accreting at a high
accretion rate. This suggests that the presence of collimated molecular jets in protostars is more closely connected to
accretion rate than system age.
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All authors Himanshu Tyagi, P. Manoj, Mayank Narang, S. Thomas Megeath, Robert Gutermuth, Lee Hartmann, Alessio Caratti o Garatti, Dan M. Watson, David A. Neufeld, Ewine F. Van Dishoeck, Neal J. Evans II, Vinod Chandra Pathak, Samuel A. Federman, Tyler L. Bourke, Yao-Lun Yang, Guillem Anglada, Henrik Beuther, Leslie W. Looney, Rolf Kuiper, Pamela Klaassen, Pooneh Nazari, Bihan Banerjee, Joel Green, Sujay Vijay Jadhav, Mayra Osorio, B. Shridharan, Amelia M. Stutz, Thomas Stanke, John J. Tobin, Lukasz Tychoniec, Scott Wolk, Manya Arora
High Energy Physics (Theory)
Ricci-flat metrics from gauged linear $\sigma$-models without RG flow
Dmitri Bykov, Ondrej Hulik, Ulf Lindström et al. (+2 more)
We investigate a class of
Ricci-flat Kähler metrics on generalized conifolds constructed via gauged linear sigma models (GLSMs) with indefinite signature. By introducing shadow coordinates (superfields) entering the sigma model with negative signature kinetic term, we show that these GLSMs yield explicit
Ricci-flat metrics on complex cones over products of projective spaces. We provide a general formula for the resulting Kähler potentials, along with detailed examples. Our results suggest new directions for the study of Calabi-Yau metrics and toric geometry, and raise interesting questions about the
geometric meaning of indefinite signature models. We also give an interpretation in terms of a novel generalized Kähler gauging.
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All authors Dmitri Bykov, Ondrej Hulik, Ulf Lindström, Martin Roček, Rikard von Unge
Materials Science
AES-Debye: an Accurate, Efficient, and Scalable Engine for Debye Scattering Calculations
Navid Panchi, Sebastian Kuckuk, Markus Wittmann et al. (+2 more)
Total scattering models are essential for characterizing the structure and disorder of nanoscale materials. The Debye scattering equation (DSE) provides a rigorous route to elastic total scattering, but its direct evaluation is computationally demanding because pairwise contributions must be accumulated at every scattering vector, whereas common acceleration strategies based on binned pair-distance distributions or gridded fast
Fourier transforms can introduce discretization and aliasing artifacts that compromise diffuse-scattering accuracy. Here, we present AES-Debye, an accuracy-preserving DSE framework that aggregates pair distances into a pair distribution function (PDF) using corrected bin centers and numerically robust accumulation to suppress discretization and summation errors. A data-locality-aware parallel design enables efficient execution on CPUs and GPUs. We demonstrate strong scalability by computing a high-resolution total scattering profile for a system of 90 million atoms, $(0.1,\mu\mathrm{m})^{3}$, in minutes on a distributed-
memory CPU platform. These capabilities extend accurate elastic total scattering calculations to large, complex systems while simultaneously providing high-resolution PDFs for downstream structural analysis.
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All authors Navid Panchi, Sebastian Kuckuk, Markus Wittmann, Michael Engel, Alberto Leonardi
Quantum Physics
Decoupling 2D translation-invariant topological CSS codes
Yifei Wang, Zhongyi Ni, Mingxin He et al. (+2 more)
Two-dimensional translation-invariant topological CSS codes on
qubits are known to be locally equivalent, after coarse-graining, to stacks of toric codes. However, existing constructions generally break more translation
symmetry than is required to remove anyon-permuting translations, leaving open whether any further obstruction exists. We prove that no such obstruction occurs: after passing to the maximal anyon-preserving superlattice, every such code admits a local
unitary decoupling into toric codes and product states. We further provide an efficient
algorithm for explicitly constructing the decoupling map, together with bounds on the required supercell size and operator spreading. The decoupling requires no additional ancillas in generic cases and extends to finite systems with suitable boundary conditions.
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All authors Yifei Wang, Zhongyi Ni, Mingxin He, Jinguo Liu, Yingfei Gu
Quantum Physics
Superselection Rigidity of Topological Calderbank–Shor–Steane Codes: From Koszul-Complex Models to Nonsplit Extensions
Hao Song
Can excitation structure classify topological
quantum codes up to finite-depth local
circuits? For translation-invariant topological Calderbank–Shor–Steane (CSS) codes in arbitrary dimensions, we introduce excitation superselection profiles $\mathscr E_\sigma$ ($\sigma=X,Z$). Their
cohomology layers $E_\sigma^\ell:=H^\ell(\mathscr E_\sigma)$ encode excitation types, fusion rules, and translation action, while $\mathscr E_\sigma$ retains cross-degree gluing. Pointlike, looplike, and higher-dimensional excitations correspond to degrees $\ell=1,2,\ldots$, respectively. Our
matrix-level Schanuel-lemma method proves single-degree superselection
rigidity: if $\mathscr E_\sigma$ is supported in a single degree $\ell$, then $E_\sigma^\ell$ and $\ell$ fix the stable translation-invariant Clifford class under a finite-resolution hypothesis automatic for
prime qudits. If $E_\sigma^\ell$ is also finite,
prime-qudit codes decouple into toric-code stacks by Clifford
circuits after coarse graining, with the exact minimal threshold set by the translation kernel. We develop a unified topological theory of Koszul-complex models (encompassing toric codes, bivariate-bicycle codes, and Haah's cubic code): for regular models, we compute $E_\sigma^\ell$, prove $\mathscr E_\sigma$ is single-degree, express finite-
torus logical modules as $\mathrm{Tor}$ groups, and obtain coarse-grained toric-stack normal forms at full length. Two constructions extend this framework to realize any admissible single-degree profile and build multi-degree extensions. The latter yields eight 3D
qubit toric-code extensions with identical layers in both Pauli sectors and trivial translation action, yet distinct size-dependent ground-state degeneracies. The seven nonsplit models require blocking to decouple. Thus, cross-degree gluing carries translation-
symmetry-enriched topological information invisible to individual layers.
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Quantum Physics
Arkopal Dutt, Dale Jacobs, John Jeang et al. (+2 more)
Learning
algorithms for structured
quantum unitaries and
Hamiltonians have primarily considered classes of processes that are local or sparse in the Pauli basis. We turn our
attention to learning $n$-
qubit quantum unitaries $U$ and
Hamiltonians $H$, given query access to $U$ or the
unitary evolution of $H$, that may be dense in the Pauli basis but still admit concise Clifford decompositions. Specifically, we consider
unitaries (or
Hamiltonians) of the form $U = \sum_i \alpha_i C_i$ over Cliffords $C_i$ with bounded Clifford extent $\sum_i |\alpha_i|$. To extract this Clifford structure, we introduce an agnostic
tomography protocol for Clifford
unitaries that given query access to an unknown
unitary $U$ with optimal Clifford fidelity $\textsf{opt}$, outputs a Clifford
unitary witnessing fidelity $\geq \textsf{opt} - \varepsilon$ for some error $\varepsilon > 0$, in time $\textsf{poly}(n,(1/\varepsilon)^{\log(1/\varepsilon)})$. We then apply this protocol to obtain
tomography protocols for
unitaries and
Hamiltonians that have bounded Clifford extent. This extends learnability of
Hamiltonians from those with sparse Pauli decompositions to those that are dense (i.e., has sparsity $\Omega(2^n)$) in the Pauli basis but are Clifford structured.
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All authors Arkopal Dutt, Dale Jacobs, John Jeang, Saeed Mehraban, Vladimir Podolskii
Strongly Correlated Electrons
Tunable Multiband Geometry and Fractional Phases in Higher Vortexable Systems
Xiaohan Wan, Siddhartha Sarkar, Ting Cao et al. (+3 more)
Higher vortexability is often viewed as a route to topological flat bands with higher-Landau-level-like
quantum geometry. Here we emphasize a complementary perspective: it provides a tunable multiband structure in which wave function geometry can be varied continuously while the band dispersion, degeneracy, and
topology remain fixed. We perform systematic exact-diagonalization studies of many-body phases in fractionally filled higher vortexable moiré systems, retaining the full flat-band
Hilbert space rather than projecting onto a single band. The multiband treatment reveals a cascade of Abelian and non-Abelian phases at zero
magnetic field, including integer and fractional
exciton insulators, Abelian fractional Chern
insulators, Moore-Read and Read-Rezayi states. At fixed filling, different phases are connected through transitions or crossovers driven solely by changes in wave function geometry, highlighting
quantum geometry itself as a direct tuning parameter between competing topological states. At fillings associated with Moore-Read and Read-Rezayi states, our calculations show that interband mixing shifts the optimal
quantum geometry regime without suppressing non-Abelian topological order under screened Coulomb interaction. Our results establish higher vortexable moiré bands as a tunable platform for exploring geometry-driven multiband topological phases at zero
magnetic field.
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All authors Xiaohan Wan, Siddhartha Sarkar, Ting Cao, Mark Rudner, Di Xiao, Kai Sun
Materials Science
Substrate-dependent thermally driven morphological evolution of Pt$_{0.9}$Ni$_{0.1}$ thin films on sapphire and langasite
M. Awais Fiaz, M. Greenslit, R. J. Lad et al. (+3 more)
We examine the thermal
evolution of 100-nm-thick Pt$_{0.9}$Ni$_{0.1}$
alloy films on sapphire and langasite substrates with a 10-nm Zr adhesion layer. Sequential
vacuum annealing from room temperature to 800 $^\circ$C produces a substrate-dependent morphological pathway that is quantified by atomic force microscopy, image
segmentation, height-distribution analysis, and effective coarsening metrics. Both types of films remain densely granular up to 400 $^\circ$C, undergo a sharp coarsening transition between 400 and 600 $^\circ$C, and evolve into coalesced faceted crystallites by 800 $^\circ$C. The mean projected feature area increases from $7.84 \times 10^2$ to $1.09 \times 10^5$ nm$^2$ on langasite and from $3.32 \times 10^2$ to $1.67 \times 10^5$ nm$^2$ on sapphire. Sapphire therefore develops the larger faceted crystallites, while langasite exhibits the larger roughness maximum at 600 $^\circ$C. Area distributions reveal that the 400-600 $^\circ$C transition does not uniformly shift the initial granular population but instead replaces it with a distinct large-feature ensemble. Height and roughness measurements show a pronounced maximum at 600 $^\circ$C, followed by partial smoothing at 800 $^\circ$C, consistent with rapid coalescence followed by faceting-limited growth. An effective Arrhenius analysis based on $\Delta\langle r^2\rangle$, with $\langle r^2\rangle = \langle A\rangle/\pi$, identifies the 400-600 $^\circ$C interval as the dominant coarsening window. These results show that the thermal stability of PtNi/Zr films on sapphire and langasite is governed by the coupled influence of
alloy mobility, interfacial energetics, and substrate-dependent morphological selection.
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All authors M. Awais Fiaz, M. Greenslit, R. J. Lad, Mauricio Pereira da Cunha, Luke Doucette, S. M. Hollen
Optics
Full-Wave Harmonic Balance Framework for Dispersive Time-Varying Photonic Structures
Mohammad R. Tavakol and Wenshan Cai
Time-varying photonic structures redistribute electromagnetic energy among Floquet harmonics, enabling frequency conversion, nonreciprocity, parametric gain, and dynamic wavefront control. Accurate modeling of realistic platforms remains challenging when temporal modulation occurs in strongly dispersive materials, because each harmonic experiences a distinct material response while remaining coupled to all others through the modulation. This work introduces a full-wave harmonic-balance framework for dispersive time-varying photonic structures. The formulation solves the steady-state Floquet response in the frequency domain by representing modulated components as induced secondary sources: volumetric polarization densities for bulk media and surface current densities for conductive sheets. Material dispersion and radiation operators are evaluated at each harmonic frequency, whereas temporal modulation enters as off-diagonal convolutional coupling in Floquet space. The framework is validated for a parametrically pumped rolled
graphene cylinder, where numerical results agree with an analytical Floquet scattering solution and resolve harmonic-specific scattering, absorption, and near fields. It is further applied to an ITO-based epsilon-near-zero (ENZ) space-time metasurface, enabling shape optimization of a reflective device that converts an optical input into sidebands and redirects them into selected spatial diffraction orders. The approach establishes a general platform for modeling and designing dispersive active photonic structures with harmonic-resolved field, power, absorption, and diffraction observables.
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Quantum Physics
Surface passivation for narrowing optical linewidth of silicon T centers in nanophotonic devices
Fariba Islam, Chang-Min Lee, Kyu-Young Kim et al. (+4 more)
Silicon T centers are promising
spin-
photon interfaces in solid-state platforms for telecom-compatible, scalable
quantum information technologies. A major challenge for T centers in nanophotonics is spectral
diffusion, where fluctuations in the local electric-field environment from surface and bulk charge states broaden the optical transition and reduce
photon indistinguishability. Strategies that directly suppress spectral
diffusion are therefore critical for improving T-center-based
quantum photonic devices. Here, we use atomic-layer-deposited Al2O3 to passivate the silicon surface and demonstrate a systematic narrowing of T center optical linewidths. Across our measurements, Al2O3 passivation reduces the T center emission linewidth by up to 57%. Complementary above-bandgap illumination and spectral hole burning measurements show that the remaining linewidth contains a significant spectral-
diffusion component caused by adjacent charge traps, while placing an upper bound of approximately 75 MHz on the homogeneous linewidth. This work provides a CMOS-compatible path toward generating indistinguishable
photons from silicon T centers for scalable
quantum photonic applications.
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All authors Fariba Islam, Chang-Min Lee, Kyu-Young Kim, Sorah Fischer, Purbita Purkayastha, Amirehsan Alizadehherfati, Edo Waks
Quantum Physics
From Nonlinear Stochastic Differential Equations to Quantum Channels: The Kolmogorov–Lindblad Mapping
Hsuan-Cheng Wu and Xiantao Li
Nonlinear
stochastic differential equations describe dynamics under uncertainty, but their nonlinear coefficients and noise averaging complicate
quantum representations. We develop a Kolmogorov–Lindblad mapping that encodes their probability laws as the position diagonals of trace-one
quantum density operators. For each Brownian realisation, a
stochastic flow transports the initial ensemble; the square-root Jacobian makes its action on half-densities
unitary. Averaging the resulting pure-state projectors gives a Lindblad equation with Hermitian jump operators. Its diagonal reproduces the Fokker–Planck density, while forward and backward intertwining identities recover bounded observables and time correlations independently of the initial coherences. A Galerkin approximation obtained by projecting the Stratonovich generators preserves the Lindblad structure. We give a residual-based error estimate and conditional
quantum costs that display the dimension dependence of approximation constants, operator normalisations, state preparation and readout. Numerical experiments for double-well Langevin dynamics and noisy Lorenz–63 show rapid convergence of selected statistics at fixed dimension. The construction provides an exact bridge from flow-regular nonlinear
diffusions to
quantum channels; any computational advantage additionally requires controlled approximation and coherent access for the chosen problem family.
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Cosmology and Nongalactic Astrophysics
The Fate of Large Scale White Noise in Second-Order Cosmological Perturbation Theory
Aurora Ireland
Working to second order in cosmological perturbation theory, we reconsider the Large Scale White Noise (LSWN) effect proposed in [2511.13866] and [2511.15803]. We demonstrate that the kurvature density variable $\Delta \rho$ does indeed develop LSWN at second order. However, contrary to the claims of [2511.15803], we show that this is not inherited as an infrared (IR) pole in the second-order comoving
curvature perturbation $R_2$. This apparent enhancement was an artifact of using a linear Poisson equation to relate two genuinely second order quantities. Further, we show that $R_2$ is protected from developing any such IR enhancement: $\lim_{k \rightarrow 0} \left( k^2 R_2 \right) = 0$, which follows from a conservation law in the soft limit. The constraint proposed in [2511.15803] and its implications for the small-scale
primordial power spectrum are therefore invalid.
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Solar and Stellar Astrophysics
Nascent Embedded-protostar Survey in Taurus (NEST) II: Measuring Dust Mass, Disk Size, and Gas Mass
Noshin Yesmin, Patrick Sheehan, John Tobin et al. (+6 more)
Envelope-embedded protostellar disks represent the earliest stage of protoplanetary disk
evolution, but their masses and sizes are difficult to measure because disk emission is entangled with the envelope. We analyze 26 protostellar disk systems in Taurus using ALMA Band 7 (345 GHz; ~0.3”) and VLA Ka-band (33 GHz; ~0.2”) continuum observations, together with molecular-line data to constrain disk gas masses. At 345 GHz, the median flux density,
dust mass, and radius are 71 mJy, 5.5 M_Mearth, and 28 AU, with 68% ranges of 54-107 mJy, 3.9-9.4 M_Mearth, and 25-39 AU. At 33 GHz, the corresponding medians are 0.43 mJy, 39 M_Mearth, and 32 AU, with ranges of 0.41-0.80 mJy, 34-52 M_Mearth, and 29-33 AU. Taurus Class I disks are fainter and less massive than those in Orion, comparable to Perseus Class I disks but fainter than Perseus Class 0 disks, and brighter and more massive than those in Ophiuchus. Within Taurus, Class 0/I disks are brighter than Class II disks at both frequencies, although their inferred
dust masses are comparable at 345 GHz and slightly higher at 33 GHz. Radiative-transfer modeling of CO isotopologue emission yields a median gas mass of 6.7 x 10^-4 M_Msun. The resulting CO-inferred gas-to-
dust ratios span a broad range, with a mean of 147 +/- 75, a median of 26, and a 16th-84th percentile range of 8-147. This distribution overlaps the Taurus Class II population at the low end and ISM-like or higher values, including the AGE-PRO Ophiuchus Class 0/I population, at the high end.
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All authors Noshin Yesmin, Patrick Sheehan, John Tobin, Aislinn Coleman-Plante, Nicholas P. Ballering, Tyler L. Bourke, Josh Eisner, Hauyu Baobab Liu, Zhi-Yun Li
High Energy Astrophysical Phenomena
Peak 'Nebular' Emission and Early Flux Excesses in Ca-strong Supernovae
C.-G. Touchard-Paxton, K. Maguire, C. Frohmaier et al. (+27 more)
Calcium-strong
supernovae (Ca-strong SNe) are a class of thermonuclear transient characterised by rapid photometric
evolution (rise times of <= 16 d) and nebular-phase spectra dominated by strong [Ca II]7291,7324 emission, in comparison to the strength of [O I]6300,6364 emission. Despite their distinctive spectra and association with remote environments, their origins remain uncertain. Using new discoveries from surveys such as the Zwicky Transient Facility, supplemented by archival data, we compile a sample of 46 Ca-strong SNe - the largest sample to date. We present a comprehensive optical photometric and spectroscopic study of Ca-strong SNe, aimed at better constraining their diversity, progenitor systems, and explosion mechanisms. Of the 35 Ca-strong SNe with spectra near peak light, we find that 32 objects exhibit significant [Ca II] emission within 10 days of peak. Forbidden [Ca II] emission is typically expected to emerge after the ejecta have expanded, cooled, and reached a sufficiently low density for forbidden transitions to occur. The prevalence of these early features in Ca-strong SNe, however, remains unexplained by current explosion models of these objects. In several objects, we identify complex, multi-component line profiles that suggest a transition between two distinct velocity regimes. These transitional features, combined with the common presence of early forbidden emission, lead us to favour a scenario in which extended material surrounds the progenitor and pre-dates the SN itself. Our results suggest that the diverse spectroscopic behaviours of Ca-strong SNe are consistent with white
dwarfs exploding in extended environments polluted by prior activity of the progenitor system.
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All authors C.-G. Touchard-Paxton, K. Maguire, C. Frohmaier, W.V. Jacobson-Galán, M. Pursiainen, C. Angus, J. Sollerman, A. Polin, J.H. Terwel, R. Seth, C. O'Donnell, S.J Smartt, S. Srivastav, A. Bochenek, T. de Boer, K.K. Das, C. Fremling, A.C. Gordon, M.J. Graham, M.E. Huber, C.-C. Lin, C. Liu, F.J. Masci, P. Minguez, G.S.H. Paek, J. Purdum, B. Rusholme, K. Smith, R. Smith, R. Wainscoat
Solar and Stellar Astrophysics
Infrared Spectroscopy and Photochemistry of Aromatic Nitriles in Para-Hydrogen Matrices
Sam McGrath, Vincent J. Esposito, Linshan Zeng et al. (+6 more)
Motivated by recent detections of several aromatic nitriles in Taurus Molecular Cloud-1, we report laboratory and theoretical investigations of the vibrational spectroscopy and photochemistry of singly and doubly cyano-substituted benzene in solid para-hydrogen
matrices. We compare the photochemistry of cyanobenzene (benzonitrile) and three dicyanobenzene isomers initiated by excitations at 193 nm. In addition, we report the photochemistry of deuterated cyanobenzene (d$_5$-cyanobenzene), enabling us to determine the major products produced during the cyanobenzene photodissociation. The major products observed in the photolysis of all the nitriles are HCN and HNC, which are likely produced by hydrogen abstraction from para-H$_2$ by the CN radical. This indicates that the major photodissociation channel involves cleavage of the bond between the ring and the nitrile group, forming the phenyl (or cyanophenyl) radical + CN. We observe secondary photoproducts similar to those found during benzene photolysis. Our findings may aid the interpretation of recent JWST mid-infrared observations of aromatics in photodissociation regions.
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All authors Sam McGrath, Vincent J. Esposito, Linshan Zeng, Thomas H. Speak, Brendan Moore, Pavle Djuricanin, Jun Miyazaki, Takamasa Momose, Ilsa R. Cooke
Quantum Physics · Cross-listed from cs.IT
Entanglement-assisted quantum locally recoverable codes: bounds and constructions with availability
Rutuja Kshirsagar, Gretchen L. Matthews and Julia Shapiro
In this work, we define
entanglement-assisted
quantum locally recoverable codes with availability, in which any set of up to $\delta-1$ erased qudits can be recovered from any one of $t$ local recovery sets, each of size at most $r+\delta-1$, with the recovery sets intersecting exactly in the erased coordinates, where $r$ is a (small) positive integer. We show that shared
entanglement permits $t>1$, meaning that multiple local recovery sets can be available for the same set of up to $\delta-1$ erasures. We establish a Singleton-like bound for this family of codes and present random constructions based on classical linear codes with Vandermonde parity-check
matrices. We also provide explicit constructions of
entanglement-assisted
quantum locally recoverable codes with availability from several classical code families and their folded versions, including Tamo-Barg codes, fiber-product codes, and algebraic-geometry codes such as one-point Hermitian and Suzuki codes.
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Strongly Correlated Electrons
Anomalous temperature dependence of polaron mobility in a nonlinear double-well potential: unbiased X-propagator approach
Stefano Ragni, Osor S. Barišić, Naoto Nagaosa et al. (+1 more)
We develop an unbiased X-propagator method for calculating finite-temperature optical conductivity $\sigma(\omega)$ and dc mobility $\mu$ for arbitrary nonlinear electron-
phonon interaction. We apply it to a polaron coupled to a double-well
lattice potential, a minimal model for strongly anharmonic polar materials. At moderate coupling, the mobility exhibits three temperature regimes associated with confinement within one well, thermal competition with the barrier, and barrier-insensitive high-temperature dynamics. This sequence produces a concave temperature dependence of the mobility that is absent in conventional linear-coupling polaron models. At strong coupling, the mobility becomes nonmonotonic, and its temperature
evolution is reflected in a characteristic redistribution of optical spectral weight. For parameters relevant to SrTiO$_3$, our results qualitatively reproduce both the anomalous concave mobility and the onset of violation of the Mott-Ioffe-Regel limit, thereby supporting nonlinear coupling to a soft anharmonic
lattice mode as a microscopic mechanism for anomalous transport in dilute polar metals.
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All authors Stefano Ragni, Osor S. Barišić, Naoto Nagaosa, Andrey S. Mishchenko
Mathematical Physics · Cross-listed from math.PR
Rooted Gibbs-DLR Measures in Planar Directed Polymers
Christopher Janjigian, Firas Rassoul-Agha and Timo Seppäläinen
We study rooted Gibbs-DLR measures in the directed
polymer model on $\mathbb{Z}^2$ with an ergodic disorder distribution which satisfies an additional mild hypothesis. We prove that the set of extremal rooted Gibbs-DLR measures is closed and totally ordered, characterize extremality in terms of path coalescence, and show that each fully supported extremal rooted Gibbs measure canonically generates a globally consistent and coalescing family of extremal rooted Gibbs measures indexed by all
lattice sites. These families are, moreover, totally ordered. Building on this structure, we prove strong existence and strong uniqueness of the associated Busemann process, together with an $L^1$ continuity
theorem for the shift-covariant Busemann cocycles which is joint in the inverse temperature, the tilt parameter, and the random environment. This yields, as a corollary, in-probability continuity of the generated extremal Gibbs measures corresponding to directions of differentiability under bounded i.i.d. perturbations of the weights. In positive temperature, it shows in-probability convergence of the generated extremal Gibbs measures. At zero temperature, it also yields quenched subsequential large deviation principles for the corresponding positive-temperature rooted Gibbs-DLR measures on path space. The rate functions are determined by a zero-temperature Busemann cocycle and vanish precisely on the infinite geodesics generated by that cocycle.
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High Energy Physics (Theory) · Cross-listed from math.DG
Eigenforms and special holonomy
Bobby Acharya, Lucía Cabrera, Simone Corbo et al. (+1 more)
We prove existence and non-existence results for $L^2$ eigenforms for the Hodge
Laplacian on complete non-compact
Ricci flat
manifolds with special holonomy, with a particular focus on gravitational instantons. We briefly describe the physical interpretation of these results in superstring and M-theory.
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All authors Bobby Acharya, Lucía Cabrera, Simone Corbo, Jason D. Lotay
Instrumentation and Methods for Astrophysics
A bestiary of low-level electrical artifacts in SPHEREx flight data
Candice M. Fazar, Michael Zemcov, C. Darren Dowell et al. (+3 more)
SPHEREx, NASA's all-sky spectrophotometric survey mission, maps the sky in 102 spectral channels from 0.75 um to 5.0 um at 6.15” resolution from low-Earth orbit using a custom readout of six HAWAII-2RG detectors. The SPHEREx instrument team and Science Data Center have built a robust science data pipeline that includes mitigating image-space artifacts arising from low-level optical and electronic effects. Analysis of first-survey flight data has confirmed predictions for some of these effects, determined differences between the laboratory and flight predictions in others, and even found new artifacts that were unanticipated. This paper will summarize our current understanding of artifacts in SPHEREx images, including image-space artifacts resulting from
cosmic rays, crosstalk and unresponsive pixels. We also present mitigation and/or masking strategies implemented to mitigate such effects, and an assessment of the possible implications for other space missions using HAWAII-2RG detectors.
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All authors Candice M. Fazar, Michael Zemcov, C. Darren Dowell, Brendan P. Crill, Chi Nguyen, Howard Hui
High Energy Physics (Theory)
On the Renormalization in Conformal Quantum Gravity
Ioseph L. Buchbinder, Petr M. Lavrov, Thomas M. Sangy et al. (+1 more)
One-loop divergences in classically conformal theory in curved spacetime is a nontrivial issue if the theory under consideration possesses gauge invariance. In this case, quantization involves introducing the gauge-fixing term and the action of ghosts, both of which are not conformal. The formal proof of the conformal invariant renormalizability in this situation, including interacting theories, has been given in the paper from 1984 by one of the present authors. Owing to BRST
symmetry, the contributions of the gauge-fixing and ghost sectors to the conformal variation of the effective action cancel each other. This cancellation does not hold in the finite part of the one-loop and higher-loops effective action, that results in the anomaly. In this paper, we extend the early results on conformal matter fields in external gravitational field and apply them to conformal
quantum gravity, including the case of conformal
gravity coupled to other conformal matter fields. The gauge-fixing in the Weyl-squared
gravity is more complicated, nevertheless, the proof of the one-loop conformal invariant renormalization using BRST
symmetry is possible. As a preliminary to conformal
quantum gravity, we also present a detailed general proof of conformal invariant one-loop divergences in the corresponding semiclassical theory.
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All authors Ioseph L. Buchbinder, Petr M. Lavrov, Thomas M. Sangy, Ilya L. Shapiro
Quantum Physics
Tensor network methods for non-perturbative dynamics of open quantum systems
Thibaut Lacroix, Adam Burgess, Nicola Lorenzoni et al. (+11 more)
The description of open
quantum system dynamics beyond the perturbative treatment (usually associated with Markovian master equations) is a computationally challenging task due to the unfavorable exponential scaling of
memory kernels. Developed over recent decades in the context of
quantum information and condensed matter, tensor networks provide both a new formalism and a toolbox for overcoming previous computational bottlenecks. This framework enables the formulation of non-perturbative, numerically exact methods for describing the dynamics of open
quantum systems to controllable numerical accuracy. In this review, we present these methods and discuss their commonalities and differences to paint a comprehensive view of the field.
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All authors Thibaut Lacroix, Adam Burgess, Nicola Lorenzoni, Julian Wiercinski, Kian Damezin, James Lim, Dario Tamascelli, Alex W. Chin, Moritz Cygorek, Brendon W. Lovett, Jonathan Keeling, Susana F. Huelga, Martin B. Plenio, Erik M. Gauger
High Energy Astrophysical Phenomena
The Galactic Neutrino Sky: Predictions from Gamma-ray Source Populations
Leo Seen and Ke Fang
High-energy
neutrino emission from the
Galactic plane has been detected at a significance of $5.7\sigma$, with a prominent excess toward the inner
Galaxy. We show that this excess can be naturally explained by the spatial distribution of
Galactic neutrino sources. By combining $\gamma$-ray source catalogs spanning GeV-PeV energies and selecting candidate hadronic emitters, we construct ReGal-$\gamma$, a template of resolved
Galactic $\gamma$-ray sources that may also produce high-energy
neutrinos. Compared with models of
Galactic diffuse emission, ReGal-$\gamma$ predicts a
neutrino intensity that is more strongly concentrated toward the inner
Galaxy. Combined with models of diffuse
cosmic-ray emission and unresolved $\gamma$-ray sources, the template reproduces both the spectral energy distribution and the
Galactic longitudinal count profile reported by IceCube without requiring additional renormalization of the emission models. We test this result using an independent $\gamma$-ray source template constructed from different catalogs and find that our conclusion is robust against uncertainties in source modeling. Future measurements of the energy-dependent longitudinal and latitudinal
neutrino distributions will provide tighter constraints on these models and help determine the spatial distribution of
Galactic neutrino sources.
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General Relativity and Quantum Cosmology
Rotating near-horizon extreme geometries in quadratic gravity
Breno L. Giacchini and Ivan Kolář
Rotating near-horizon extreme solutions of quadratic
gravity are analyzed combining power series expansions and numerical calculations. Restricting to geometries with
symmetries of the near-horizon extreme Kerr black hole (i.e., with the $\mathrm{AdS_2}$-structure), spherical horizon
topology, and equatorial reflection
symmetry, we introduce conformal coordinates simplifying the field equations of Einstein–Weyl
gravity, i.e., quadratic
gravity with vanishing scalar
curvature. Employing the Frobenius analysis, we classify all power series solutions expanded around the equator as well as the poles, and obtain the recurrence relations. With the help of numerical analysis, we study fine-tuning of the free parameter to satisfy the global constraints on regular near-horizon extreme geometries. Computations of the horizon area, horizon scalar
curvature, and rotational scalar reveal strong horizon deformations in some Bachian branches. Moreover, the absence of regular Bachian near-horizon geometries above a finite horizon area suggests an upper bound on the size of the corresponding extremal rotating black holes.
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Mesoscale and Nanoscale Physics
Topological phase rectification via Aharonov-Bohm interference in a Majorana–quantum-dot interferometer
Jia Liu, Hao-Yuan Yang, Yuan Hong et al. (+5 more)
We propose and theoretically investigate a topological superconducting rectifier based on a
quantum-dot–Majorana interferometer. The Aharonov-Bohm phase, controlled by a
magnetic flux threading the interferometer loop, tunes the
quantum interference between a trivial $2\pi$-periodic
quantum-dot channel and a topological $4\pi$-periodic Majorana channel. At non-integer flux, this interference generates a persistent current background $I_{\rm off}$ that shifts the current-phase relation into a unipolar regime, in which the supercurrent flows strictly in one direction. We introduce a signed unipolarity factor $\eta_u$, with $|\eta_u|>0.5$ defining the unipolar regime, and establish its quantitative relationship to the conventional diode efficiency $\eta$. The unipolarity proves robust against variations of the
quantum-dot level,
spin polarization, and Majorana hybridization, is enhanced by stronger Majorana coupling and Rashba
spin-orbit interaction, and persists at realistic temperatures and under quasiparticle poisoning. We further propose a topological diode figure of merit $\mathcal{Z}_{\rm TD}$, defined from the
Fourier spectrum of $\eta_u$, whose nonzero value provides a model-independent signature of the $4\pi$-periodic Majorana channel and distinguishes topological from trivial rectification mechanisms. Our findings establish the
quantum-dot–Majorana interferometer as a promising route toward high-performance topological superconducting diodes with clear experimental signatures accessible via standard dc transport measurements.
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All authors Jia Liu, Hao-Yuan Yang, Yuan Hong, Li Ma, Feng Chi, Zi-Chuan Yi, Li-Ming Liu, Zhen-Guo Fu