Astrophysics of Galaxies
Differential Reddening and Extinction Law Analyses of Galactic Open Clusters
Xiaohan Chen, Shu Wang and Xiaodian Chen
Extinction significantly affects open cluster parameters and their use in studies of
Galactic structure, yet homogeneous large sample measurements of open cluster extinction properties remain limited. Using
Gaia-era open cluster member samples combined with multi-band photometry and
stellar parameters, we derive color excesses of member
stars and provide the homogeneous characterization of the mean reddening, differential reddening, and color excess ratio (CER) at the cluster scale. Differential reddening increases systematically with mean reddening, with highly reddened clusters near the
Galactic plane showing stronger extinction variations.
Star-by-
star reddening corrections narrow color–magnitude diagram (CMD) sequences in 369 of 435 clusters (85%) with reliable CMD-width measurements, and cluster color excess maps reveal small-scale extinction structures. The median CER is compatible with the standard diffuse interstellar medium extinction curve, while the broad CER distribution and its large-scale variations across the
Galactic disk likely reflect differences in the dominant
dust environments sampled along different
Galactic sight lines.
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Quantum Physics
Heat transport in driven quantum systems: Comparison between the Floquet-Redfield equation and the master equation in the instantaneous eigenbasis
Luca Magazzù, Christoforus Dimas Satrya, Aleksandr S. Strelnikov et al. (+2 more)
We provide a comprehensive study of heat transport in periodically driven
quantum systems using a master equation approach in the Floquet basis. Starting from the exact, formal expressions, we obtain, within the weak coupling regime of system-bath coupling, a generalized Floquet-Redfield master equation which does not involve Markovian or secular approximations and the corresponding formula for the heat current. From this approach we derive the standard, full secular master equation. Moreover, we present a master equation for the driven
spin-
boson model in the instantaneous eigenbasis. The different approaches are compared by applying them to the steady-state heat transport in the driven
spin-
boson model. An analytical solution is provided for the master equation in the instantaneous eigenbasis which reproduces the numerics and explains the features of the heat current as a function of the drive parameters.
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All authors Luca Magazzù, Christoforus Dimas Satrya, Aleksandr S. Strelnikov, Bayan Karimi, Jukka P. Pekola
Astrophysics of Galaxies
Radio Properties of Narrow-Line and Broad-Line Seyfert 1 Galaxies
K. É. Gabányi, S. Komossa, A. Mezősi et al. (+2 more)
Narrow-line Seyfert 1 (NLS1)
galaxies host active
galactic nuclei (AGN) with narrow optical emission lines of the broad-line region. This is often explained with a relatively lower mass of the central supermassive black hole and super-Eddington
accretion. We compared the
radio properties of large samples of NLS1 and broad-line Seyfert 1 (BLS1)
galaxies compiled from the Sloan Digital Sky Survey. We cross-matched the NLS1 and BLS1 samples with the Faint Images of the
Radio Sky at Twenty-Centimeters (FIRST) sky survey at 1.4 GHz and the first and second epoch data of the Very Large Array Sky Survey (VLASS) at 3 GHz. We calculated the
radio spectral indices, the 1.4-GHz
radio power, and the
radio loudness. We found lower 1.4-GHz
radio detection rates for the NLS1
galaxies. The median
radio loudness values, the fraction of
radio-loud AGN, and the median 1.4-GHz
radio power are also lower for the NLS1 sample. The median spectral indices imply a slightly steeper
radio spectrum for the NLS1 sample than for the BLS1 sample. Comparison of the
star formation rates estimated from the
radio data and the infrared measurements of the Wide-field Infrared Survey Explorer satellite indicated that more than half of the FIRST- and VLASS-detected NLS1 and BLS1
galaxies contain
radio-emitting AGN.
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All authors K. É. Gabányi, S. Komossa, A. Mezősi, E. Forgács-Dajka, S. Frey
High Energy Physics (Theory)
Frame-dependency of the confinement temperature in a strongly-coupled plasma under rotation: a holographic description
Nelson R. F. Braga and Alexsandre L. Ferreira Jr
Recently, it was demonstrated that the disagreement between
lattice calculations and
holographic models, regarding rotational effects in the
quark-
gluon plasma (QGP), occurs due to different choices of reference frames. While a static observer measures a confinement temperature that decreases with rotation, one in a co-rotating frame finds the opposite behavior. Both results are correct, and a comprehension of the frame-dependency of the critical temperature is a significant step in the description of the QGP under rotation. In this article, we generalize this previous
holographic result by describing the
plasma through the most general Myers-Perry black hole solution. This breaks the spherical
symmetry present in the equal angular momentum case, considered before. As a consequence, the local temperature measured by a co-rotating observer has a non-trivial angular dependence: it can decrease, increase or even behave non-monotonically when rotational velocity increases.
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High Energy Physics (Theory)
3d $\mathcal{N}=$ 4 rank-0 SCFT from punctured lens space
Sungjoon Kim
Gang-Kim-Stubbs theory $\mathcal{T}_n$ — a pioneering 3d bulk description of $M(2n+3,2)$ Virasoro minimal model as $\mathcal{N}=4$ rank-0 superconformal field theory upon topological A-twist — is derived from the compactification of a pair of parallel M5-branes on lens space $L(2n+3,2)$ with a single vertex removed. From this perspective, we propose a family of 3d $\mathcal{N}=2$ abelian gauge theories arising from the punctured $L(2n+3,1)$ lens space whose infrared phases realize the
unitary member in the Galois orbit of $M(2n+3,2)$ modular tensor category. We also
conjecture self-mirror rank-0 fixed points from amphichirality condition of the lens space.
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General Relativity and Quantum Cosmology
Differential Obstructions to Curvature-Dependent Conformal Transformations
David S. Pereira, Francisco S.N. Lobo and José Pedro Mimoso
Curvature-dependent conformal rules are local forward assignments on known metrics, but they are not generically local changes of metric variables. We study the nondegenerate class $\widetilde g_{\mu\nu}=F(R[g])g_{\mu\nu}$, with $F>0$ and $F_R\neq0$. Introducing an independent auxiliary scalar localizes the forward map, while recovering the original metric requires a differential constraint. The complete inverse metric tangent map contains the nonpolynomial projector $\xi^\mu\xi^\nu/\xi^2$; hence no differentiable finite-jet inverse, i.e., a formula involving only finitely many derivatives at the same point, exists on an open set of unrestricted metrics. Branchwise functional inverses may nevertheless exist after boundary or Cauchy data are specified. Metric $f(R)$
gravity gives an explicit realization: its local Einstein-frame scalar–tensor representation is a parent theory, whereas a metric-only Einstein-side description requires a differential section governed by a normal operator. We derive the pulled-back classical Hessian and its off-shell
embedding term, and in the quadratic model show how constrained Gaussian elimination produces the scalaron nonlocal kernel, the corresponding normal determinant for the displayed measure, and the zero-mode compatibility condition. Exact parent and metric solutions remain equivalent; the obstruction concerns locality and the off-shell variational and fluctuation domains. These results provide a precise framework for assessing
curvature-dependent frame transformations in modified
gravity and clarify their implications for effective actions, semiclassical analyses, and
quantum frame equivalence.
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Optics
Geometric Parametric Instability in Nonlinear Multipass Cells
Chao Mei, Junhong Yang, Tao Sun et al. (+5 more)
Geometric parametric instability (GPI) is the resonant growth of discrete spectral sidebands enabled by longitudinally periodic multimode
evolution and has been studied primarily in graded-index fibers. Here we show theoretically and numerically that GPI can occur in gas-filled nonlinear multipass
cells (MPCs). By mapping a mode-matched MPC onto an equivalent waveguide, we derive a Floquet quasi-phase-matching condition governed by the single-pass Gouy-phase imbalance of the signal–idler pair relative to the pump pair. The theory predicts the small-signal gain and bandwidth. A pump-depleted coupled-mode model (CMM) further relates the maximum converted fraction to the residual phase mismatch. The CMM predicts multiple geometrically tunable sideband pairs associated with different radial indices and Floquet orders. For argon at $5$~bar, varying the cavity geometry shifts the sideband detuning from approximately $96$ to $46$~THz when the $p_{\mathrm{s}}=1$, $h=0$ branch is considered. A truncated multimode generalized nonlinear Schrödinger equation (MMGNLSE) model is used for numerical simulations with a semiclassical
stochastic seed corresponding to one
photon per spectral mode. The MMGNLSE simulations reproduce the predicted sideband frequencies and reveal pump depletion and competition among the retained radial channels. GPI in MPCs may therefore limit spatial beam quality in nonlinear pulse compression while providing a tunable mechanism for broadband multicolor generation.
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All authors Chao Mei, Junhong Yang, Tao Sun, Qian Gao, Jinhui Yuan, Jintao Fan, Peilong Yang, Günter Steinmeyer
General Relativity and Quantum Cosmology
Gravitational Wave Standard Sirens as Probes of Lorentz Violation in Bumblebee Gravity
Ayan Banerjee, Bobur Turimov, Francisco Tello-Ortiz et al. (+2 more)
Gravitational-wave standard sirens provide a direct measurement of luminosity distance and therefore offer a new way to test
gravity over cosmological scales. We use this idea to forecast the sensitivity of the Einstein
Telescope (ET) to Lorentz violation in Bumblebee
gravity, and we examine how the forecast changes when Type~Ia
supernova information is added. A timelike Bumblebee
vacuum expectation value can affect the
cosmic expansion and, when it evolves with
redshift, the propagation amplitude of gravitational waves. We study a constant-field case and an evolving-field case using mock ET catalogues with $10^3$ events together with a Pantheon+-like
supernova sample. The
supernova data substantially improve the background parameters: in the constant-field case the uncertainties in $H_0$ and $\Omega_m$ decrease by a factor of about $4.4$, while in the evolving-field case they decrease by factors of about $1.6$ and $6.2$, respectively. By contrast, the Lorentz-violating parameter $\ell_0$ remains prior dominated, and the
evolution index $\beta$ is constrained only by the gravitational-wave sector. The best forecast precision, $\Delta\ell_0\simeq0.028$, is about $4.7\times10^{12}$ times weaker than the bound implied by GW170817. The principal result is therefore a quantified sensitivity gap rather than a forecast detection. We also express the prediction in the phenomenological $(\Xi,n)$ description of modified gravitational-wave propagation, allowing direct comparison with standard-siren studies of other
gravity models.
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All authors Ayan Banerjee, Bobur Turimov, Francisco Tello-Ortiz, Sulton Usanov, Farkhod Turaev
High Energy Astrophysical Phenomena
X-ray Flaring and Variability in NGC 1275, the Heart of the Perseus Cluster
Sarah Ketchum, Jon M. Miller, S. W. Allen et al. (+6 more)
NGC 1275 is the central
galaxy in the Perseus Cluster. The active
galactic nucleus (AGN) within NGC 1275 is notable for its strong and variable
radio activity, tied to the production of
radio jets that inflate large bubbles in the hot intracluster medium (ICM). High spatial resolution X-ray imaging can separate the AGN from the bright ICM, but monitoring the mass
accretion rate onto the black hole and establishing disk-jet connections in NGC 1275 requires a high cadence. Here, we report on X-ray monitoring of NGC 1275 using data taken over 20 years with the Neil Gehrels Swift Observatory. Modeling the temporally constant ICM in each observation allows X-ray emission from
accretion onto the black hole to be traced reliably, with typical flux errors of $\sim 3\%$. X-ray flaring by a factor of $\sim2$ over mere days is detected starting on MJD 59956 (2023 Feb. 21). The
flares imply an emission region consistent with $r \leq 870~(10^{8}~M_{\odot}/M_{BH})~ GM/c^{2}$. The profile of the flaring is inconsistent with simple predictions for
tidal disruption events. A
flare appears roughly 300 days later in
radio monitoring data at 43 GHz. Overall, our results indicate that coordinated, moderate-resolution X-ray imaging and
radio monitoring could potentially trace disk-jet connections in the AGN that most vividly impact large-scale structure, and be extended to other sources that impact their hosts.
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All authors Sarah Ketchum, Jon M. Miller, S. W. Allen, Doyee Byun, Tianyin Hu, Missagh Mehdipour, Veronica Tananko, Xin Xiang, Irina Zhuravleva
Mathematical Physics · Cross-listed from math.RT
Categorification of the genus two DAHA
Semeon Arthamonov, Ievgen Makedonskyi and Daniil Sarafannikov
We construct three derived endofunctors on the derived category of graded integrable representations of the current
algebra of a flat degeneration of $D(2|1,\alpha)$, and prove that their classes in the Grothendieck group are the genus two Macdonald operators. Computing the graded $\operatorname{Ext}$ pairing explicitly, we deduce the self-adjointness of the genus two Macdonald operators and the orthogonality of genus $2$ Macdonald
polynomials with respect to the certain skew-bilinear form.
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Earth and Planetary Astrophysics
Stellar tidal systematics in apsidal-motion searches for circumbinary planets: CH Ind and SW CMa
Qunfeng Jiang
Thornton et al. (2026) reported 27 non-transiting circumbinary-
planet candidates from excess apsidal motion in TESS eclipsing-binary timings. The classical
stellar contribution is sensitive to target-specific radii, apsidal constants $k_2$, and rotation. We re-evaluate two evolved, double-lined eclipsing binaries in that sample: the pulsating system CH Ind and the Am system SW CMa. Their component masses and radii have been measured in dedicated binary studies, allowing the
stellar contribution to be calculated directly. For CH Ind, six independent TESS sector nodes give $\dot{\omega}_{\rm obs}=1.82^{+0.99}_{-0.94}\times10^{-3}\ {\rm deg\,cycle^{-1}}$, while a coeval fit to the measured binary components predicts $\dot{\omega}_{\rm stars}=2.05^{+0.43}_{-0.34}\times10^{-3}\ {\rm deg\,cycle^{-1}}$. For SW CMa, its measured dimensions raise the classical term by a factor of about 16; the published target-specific prediction, $0.670\pm0.020\times10^{-3}\ {\rm deg\,cycle^{-1}}$, agrees with the observed $0.690\pm0.050\times10^{-3}\ {\rm deg\,cycle^{-1}}$. Neither system shows a significant excess prograde component. The comparison shows that candidates from a bulk search require target-specific binary models before a third-body interpretation is assigned.
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Mesoscale and Nanoscale Physics
Topological Superconductors in Doubly-Coupled Nanowires with Altermagnetism
Hongfa Pan, Haoyang Wang, Wenguang Zhu et al. (+1 more)
We theoretically investigate the possibility of engineering topological superconductivity in doubly coupled nanowires integrating proximity-induced superconductivity and altermagnetism. By tuning experimentally accessible parameters, we find four distinct topological superconducting phases: class D, class BDI, and two phases hosting two Majorana zero modes per end, protected respectively by
spin-group and
magnetic point-group
symmetries. Beyond inheriting the advantages of alternating?magnetism induced topological superconductivity, our system provides multiple tuning knobs (e.g., superconducting phase difference and inter-wire coupling) to control topological properties.
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All authors Hongfa Pan, Haoyang Wang, Wenguang Zhu, Zhenhua Qiao
Optics
Inverse-Designed High-Q and Small-Mode-Volume Silicon Nitride Photonic Crystal Cavities for Second- and Third-Harmonic Generation
M. Takiguchi, P. Heidt, X. Z. Lim et al. (+7 more)
SiN photonic
crystal (PhC) cavities are promising platforms for nonlinear and
quantum photonics because of their wide transparency window, CMOS compatibility, and negligible two-
photon absorption. However, realizing high-Q/V cavities remains challenging because of the relatively low refractive index of SiN. Here, we employ inverse design to optimize a two-dimensional SiN PhC cavity and experimentally demonstrate a quality factor of approximately 80,000, the highest reported for a near-stoichiometric SiN 2D PhC cavity. Furthermore, both second- and third-harmonic generation are observed from the same cavity, providing experimental evidence of strong optical confinement and large Q/V. Our results establish inverse-designed SiN PhC cavities as a promising platform for nonlinear photonics and future heterogeneous integrated photonic devices.
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All authors M. Takiguchi, P. Heidt, X. Z. Lim, J. Zöllner, S. Yanagimoto, K. Nakayama, T. Aihara, M. Ono, H. Sumikura, M. Notomi
High Energy Astrophysical Phenomena
The low luminosity end of Galactic HMXBs with eROSITA: Establishing a luminosity floor for accreting BeXRBs
Aafia Zainab, Philipp Thalhammer, Nico Zalot et al. (+18 more)
We present a first look at the
Galactic population of heretofore known HMXBs as observed by SRG/eROSITA during its first four surveys. eROSITA's sensitivity of $\sim10^{-13}\,\mathrm{erg}\,\mathrm{s}^{-1}\,\mathrm{cm}^{-2}$, translating to $10^{32}$-$10^{34},\mathrm{erg}\,\mathrm{s}^{-1}$ in luminosity for most known HMXBs in the Milky Way, has thus far never been reached by any wide-area survey instrument. We present the extended log N-log L distribution of known HMXBs reaching down to $10^{32}\,\mathrm{erg}\,\mathrm{s}^{-1}$ using eROSITA, and show the large scatter that can be induced by source intrinsic variability. We present sub-type resolved luminosity distributions, showing that the Supergiant X-ray binaries (SgXBs) and Be X-ray binaries (BeXRBs) occupy different parts of the overall distribution, and reanalyse RXTE/ASM data and MAXI for comparison to eROSITA. The luminosity regime uncovered by eROSITA allows a systematic study of the "transient" BeXRBs, which are typically below the detection threshold of monitors outside of outburst, and whose low luminosity behavior has been a longstanding question. Signatures of stable
accretion at low luminosities have been observed with pointed instruments for a fraction of the overall sample, so far. With the eROSITA results, we posit that
accretion outside of outburst is likely the norm, since a vast majority (> 80%) of BeXRBs are detected at luminosities at least an order of magnitude higher than expected for the most X-ray luminous Be
stars. We discuss the observed luminosity in the context of cold disk
accretion and the "propeller" mechanism. We highlight a small subpopulation of "isolated" Be-
stars that reach luminosities comparable to the least luminous BeXRBs, hinting at the presence of compact object companions.
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All authors Aafia Zainab, Philipp Thalhammer, Nico Zalot, Artur Avakyan, Jakob Stierhof, Ekaterina Sokolova-Lapa, Victor Doroshenko, Victoria Grinberg, Peter Kretschmar, Galina Lipunova, Nazma Islam, Matthias R. Schreiber, Christian Kirsch, Steven Hämmerich, Philipp Weber, Ralf Ballhausen, Alicia Rouco Escorial, Joel Coley, Richard Rothschild, Katja Pottschmidt, Joern Wilms
Instrumentation and Methods for Astrophysics
Optical concept model of the future cosmology project BISOU
Morgane Loquet Le Gall, Bruno Maffei, Pierre Guiot et al. (+2 more)
We present an optical analysis of BISOU (Balloon Interferometer for Spectral Observations of the
primordial Universe), an astronomical balloon-borne pathfinder spectrometer developed as part of a preparatory study for a future space mission aiming at measuring spectral distortions of the
cosmic microwave background (CMB). The BISOU optical system is based on a differential polarizing
Fourier Transform Spectrometer (FTS) that receives inputs from both a sky-facing
telescope and an internal calibration source. The FTS focal planes are equipped with bolometric detectors coupled to multimode feed horns, with distinct focal planes dedicated to the low (90 - 300GHz) and high (0.3 - 1.5THz) frequency bands. The optical analysis first relies on ray-tracing simulations to establish the overall configuration of the system, before proceeding to more advanced Gaussian beam and physical optics analyses.
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All authors Morgane Loquet Le Gall, Bruno Maffei, Pierre Guiot, Creidhe O'Sullivan, Neil Trappe
High Energy Physics (Theory)
Phase transition from eigenstate thermalization: forbidden singularity and instanton proliferation via AGT correspondence
Yongjiang Xu, Weixin Sun, Chushun Tian et al. (+1 more)
In theoretical physics, finding connections between problems that appear in distinct contexts is an important way to leapfrog progresses, often by illuminating deep aspects that may otherwise seem obscure. In this paper, we consider in 2d CFTs the phenomenon of forbidden singularities in auto-correlation functions – a key signature of eigenstate thermalization. We show that they correspond to phase transitions in the context of eigenstates. The connection is made explicit by utilizing the AGT correspondence, which relates eigenstate auto-correlations to the Nekrasov partition functions describing an instanton gas of the $\mathcal{N}=2$ SUSY gauge theories. We show that by taking the counter-part of the heavy-light limit, two phases emerge for the instanton gas. They are dominated by configurations represented by string-like Young tableaux with distinct structures and thermodynamic properties, which bare resemblance to the confined and the deconfined phases. A phase transition occurs as instantons proliferate from one side, in a manner that mimics the Lee-Yang theory. We work out the critical fugacity and find it corresponding exactly to the forbidden singularity.
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All authors Yongjiang Xu, Weixin Sun, Chushun Tian, Huajia Wang
Earth and Planetary Astrophysics
Assessing Planetary Stability and Long-Term Habitability in Nearby Stellar Binaries: 70 Oph, 36 Oph, $\gamma$ Leo
Alyssa R. Jankowski, Juliette Becker, Catherine A. Clark et al. (+8 more)
Binary
stars are common and have the potential to host habitable
planets, which may reside in more complex habitable zones as compared to
planets orbiting single
stars. In this work, we use numerical simulations to assess the possibility that bright, nearby
stellar multiples 36 Oph, 70 Oph, and $\gamma$ Leo could host habitable
planets. We find that for the 36 Oph A/B system and for the 70 Oph A/B system, the
stars can support
planets residing in permanently habitable zones with low ejection rates and moderate eccentricity oscillations. The habitable zones around the red
giants in the $\gamma$ Leo system exhibit severe dynamical instability due to the high binary eccentricity, eliminating the habitable zones around both
stars. In these two systems, we find that
planets in the habitable zone with orbits coplanar to that of the binary become uninhabitable due to interactions with the binary only 1.5% - 1.8% of the time, while
planets with orbits 45 degrees misaligned to the plane of the binary experience larger oscillations in orbital eccentricity and as a result become uninhabitable 4.8% - 5.4% of the time. Our results identify 36 Oph and 70 Oph as promising targets for future missions such as the Habitable Worlds Observatory and SHERA, while suggesting that the
stars in $\gamma$ Leo are unlikely to host any habitable
planets. Our methods can be applied more generally to other binary
stellar systems to refine target lists for upcoming habitable
planet searches.
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All authors Alyssa R. Jankowski, Juliette Becker, Catherine A. Clark, Eric E. Mamajek, Jessie L. Christiansen, Yiting Li, Eduardo Bendek, Daniella Gagliuffi, Mark R. Giovinazzi, Simone Lilavois, Ryan Purviance
Strongly Correlated Electrons
Emergent Symmetry-Protected Topological Phases via Polyakov Confinement in Quantum Spin Systems
Li-Wei He, Shun-Li Yu and Jian-Xin Li
A main theme in modern condensed matter physics is the emergence of fractionalized excitations and gauge structures from
quantum spin systems. However, understanding how these exotic degrees of freedom reconfine into new phases of matter remains a fundamental challenge. In this work, we demonstrate that Polyakov's confinement mechanism-a foundation of compact gauge theory-can serve as a dynamical engine to transform a Dirac
spin liquid into a
symmetry-protected topological (SPT) state. Starting with a Dirac
spin liquid with
spin-dependent gauge fluxes, we show that the single-occupancy constraint inherent to the physical
Hilbert space triggers monopole condensation, dynamically confining bulk spinons while preserving gapless edge modes-realizing a spinon analog of the
quantum spin Hall effect. Using a large-scale variational Monte Carlo simulation on a triangular antiferromagnet with an additional Dzyaloshinskii-Moriya interaction, we provide microscopic evidence for this confined SPT phase, including a characteristic area law for the Wilson loop and vanishing topological
entanglement entropy. Furthermore, we identify a measurable
spin-pump response under
magnetic fields, which directly encodes the Berry
curvature of the parent Dirac cones. Our results reveal a previously unexplored pathway to SPT physics, bridging the fields of gauge theory,
quantum magnetism, and topological matter.
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General Relativity and Quantum Cosmology
White dwarfs in minimal dilatonic gravity
Denitsa Staicova
We study static, spherically symmetric white
dwarfs in minimal dilatonic
gravity (MDG) – a Brans-Dicke theory with fixed coupling $\alpha^2=1/3 $ and free Compton length $\lambda_{\Phi}$. Solving the full relativistic structure equations we find that MDG white
dwarfs are strictly sub-Chandrasekhar for every $\lambda_{\Phi}$: the maximum mass falls from $1.425\,M_\odot$ in GR to $1.27\,M_\odot$ at $200$ km and $1.09\,M_\odot$ at $500$ km. The ratio by which MDG reduces the maximum mass is robust against the equation of state. Including rigid rotation near mass shedding, consistency with the most massive observed white
dwarfs restricts $\lambda_{\Phi} \lesssim 300$ km. An independent gravitational-
redshift bound gives $\lambda_{\Phi} \lesssim 720$ km. Because the dilaton mass is density-independent the same coupling produces a percent-level altitude dependence of the Kepler-inferred $ GM_\oplus$, constraining it from the
Solar-System side. To tackle the problem, we introduce a free-boundary collocation method with a linearized-exterior Robin condition that eliminates the exponential stiffness of shooting methods and gives access to the screened regime in double precision.
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Soft Condensed Matter
Substrate-Directed Wetting Layers in Bicontinuous Particle-Stabilised Emulsions
Jesse M. Steenhoff and Martin F. Haase
Bicontinuous interfacially jammed emulsion gels (bijels) facilitate efficient mass transport across multiple length scales due to their interwoven structure of particle-stabilised
liquid channels. This unique morphology imparts considerable potential for applications in separation and catalysis, particularly when fabricated via solvent-transfer-induced phase separation (STrIPS). STrIPS enables the continuous, large-scale production of nanostructured bijel films on solid substrates, yet the influence of the substrate properties on the formation dynamics and final morphology remains insufficiently understood. In this study, this relationship is elucidated by preparing STrIPS bijel films on silane-functionalised glass substrates with selectively controlled wettability and analysing the resulting structure with confocal microscopy. The results showed the presence of notable wetting layers at the bijel-substrate interface, whose thicknesses could be tuned through the nanoparticle weight fraction. In line with numerical simulations, increasing the substrate hydrophobicity drove a transition from a laminar, water-rich surface layer to a patch-like, progressively oil-rich structure. These findings provide crucial insight into the structure-directing role of substrates in supported bijel films, which aids their application as functional materials.
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Quantum Physics
Homomorphic Aggregation of Continuous-Variable GKP States
Nilesh Vyas
Aggregating logical information in continuous-variable
quantum networks is essential for distributed
quantum architecture. However, direct passive linear optics degrade non-Gaussian Gottesman-Kitaev-Preskill (GKP) grid states via
symplectic lattice compression and
entanglement-induced decoherence when auxiliary modes are discarded. We present an active, measurement-based continuous-variable network primitive for combining spatially distributed computational-basis payloads. Utilizing GKP Bell states, homodyne measurements, and conditional feed-forward phase-space displacements, we construct a completely positive trace-preserving (CPTP) map that evaluates a logical XOR operation on computational-basis inputs. We bound the Heisenberg action of the physical finite-squeezing channel on logical Pauli generators, demonstrate measurement-specific homodyne-outcome hiding for continuous-variable
quantum one-time pads (CV-OTP) with an explicit prefactor bound $D_{\mathrm{TV}} \le 1.60 e^{-r}$, and evaluate logical success probabilities under physical optical loss and network scaling constraints.
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Instrumentation and Methods for Astrophysics
Optical development of the BISOU breadboard
Morgane Loquet Le Gall, Creidhe O'Sullivan, Bruno Borgo et al. (+4 more)
BISOU (Balloon Interferometer for Spectral Observations of the
primordial Universe) is an astronomical balloon-borne pathfinder developed as part of a preparatory study for a future space mission aimed at measuring spectral distortions of the
cosmic microwave background (CMB). A laboratory breadboard of the instrument is being developed at the Institut d'Astrophysique Spatiale (IAS), enabling the characterization of subsystems and instrument systematic effects, particularly in the optical system. The optical system is based on a differential polarizing
Fourier Transform Spectrometer (FTS) that receives inputs from both a sky-facing
telescope and an internal calibration source. The FTS focal planes include sub-K detectors coupled to multimode feed horns. The full spectral band, spanning between 90 and 1500 GHz, is sub-divided into two frequency sub-bands, thanks to the use of a dichroic. The optical analysis first relies on ray-tracing simulations to establish the overall configuration of the system, before proceeding to more advanced Gaussian beam and physical optics analyses.
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All authors Morgane Loquet Le Gall, Creidhe O'Sullivan, Bruno Borgo, Clémence De Jabrun, Valentin Sauvage, Neil Trappe, Bruno Maffei
Atomic Physics
Critical Microwave Mach-Zehnder-Type Interferometry with Dual-LO Rydberg Atoms
Jun-Rong Chen, Guo-Qing Qin, Peng-Fu Liang et al. (+7 more)
High-precision phase measurement of microwave fields underpins a wide range of applications, including wireless communications, distributed radar,
plasma diagnostics, and
antenna metrology. Existing Rydberg-atom-based approaches, however, often face trade-offs among phase resolution, measurement range, and system complexity. Here we demonstrate a Rydberg-atom-based microwave Mach-Zehnder-type interferometer using a dual-local-oscillator configuration. The two local oscillators establish two coherent interferometric pathways in the Rydberg medium. Their coherent mixing with the signal field produces an interferometric intermediate-frequency output governed by a phase-to-intensity transfer characteristic that enables critical-point enhancement. This scheme supports direct phase
retrieval with a resolution exceeding $0.1^\circ$ and unambiguous full $360^\circ$ phase coverage with the reconfigurable dual-LO architecture. Moreover, near the critical interference point, the system exhibits a sharply enhanced phase-to-amplitude transduction, where weak amplitude variations are converted into pronounced phase responses, yielding a sensitivity enhancement exceeding 25 dB. Besides, the same interferometric transfer mechanism enables microwave propagation-distance and polarization metrology, achieving a propagation-distance precision below 20 $\mu$m at 5.7 GHz together with a polarization-angle resolution exceeding $0.1^\circ$. This approach eliminates the need for complex optical configurations and lock-in detection, providing a simple, scalable, and reconfigurable Mach-Zehnder-type
quantum microwave interferometry framework for multifunctional high-precision microwave metrology.
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All authors Jun-Rong Chen, Guo-Qing Qin, Peng-Fu Liang, He Hao, Ming-Min Zhao, Ling-Qiang Meng, Gui-Lan Li, Min-Jian Zhao, Bin-Bin Wei, Hao Tian
Atmospheric and Oceanic Physics
Statistical Noise and Missing Forcing Limit Estimates of Earth's Feedback from Prescribed Sea-Surface Temperature Simulations
Gergana Gyuleva, Reto Knutti, Robin Noyelle et al. (+3 more)
Earth's feedback parameter measures how the Earth system responds to forcing and is inversely proportional to
climate sensitivity. Sea-surface temperature (SST) patterns can modulate the value of the feedback parameter. Differences between observed and simulated SSTs have raised the question how the observed SSTs
evolution impacts the global feedback. The standard method for estimating this effect uses observed SSTs prescribed to an atmospheric model with fixed pre-industrial atmospheric forcing. This method makes two assumptions: first, that the observed SSTs capture all relevant effects from the forcing, so that prescribing a time-varying forcing is unnecessary; second, that the temporal variations in the feedback parameter are driven by the evolving SST pattern and can be estimated via moving-window regressions. We test these assumptions by running controlled experiments in which SSTs from fully-coupled historical simulations are prescribed to an atmospheric model. We find that the prescribed-SST experiments fail to capture the coupled feedback
evolution. This is explained by two effects: First, the absence of prescribed atmospheric forcing, and second, statistical noise arising from the computation of moving-window regressions. We find no evidence of any significant relationship between evolving SST patterns and changes in the feedback time series in a 4000-year pre-industrial control simulation. Any trends in the feedback parameter detected on timescales shorter than ~100 years are indistinguishable from statistical noise, making their attribution to the evolving SST pattern extremely difficult. Our results imply that prescribed SST simulations offer limited potential for inferring temporal changes in Earth's parameter over the observational period.
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All authors Gergana Gyuleva, Reto Knutti, Robin Noyelle, Urs Beyerle, Erich Fischer, Sebastian Sippel
Quantum Physics
Heterogeneously Integrated Squeezed-Light Generation and Detection on a Single Photonic Chip
Haoran Chen, Benjamin Westcott, Fatemehsadat Tabatabaei et al. (+10 more)
Squeezed light underpins
quantum-enhanced sensing and continuous-variable
quantum information processing, and integrated photonics offers a route to producing it at scale. Universal to these applications are squeezed-light generation and measurement. Importantly,
quantum measurements serve not only as readout but also as active operations in
quantum-state
evolution. However, integrating squeezed-light generation and photodetection on the same photonic chip has remained challenging because they impose fundamentally conflicting material requirements: low optical loss to preserve
quantum correlations, but efficient
photon absorption for photodetection. Here, we demonstrate squeezed-light generation, routing, and balanced homodyne detection integrated on a single photonic chip through heterogeneous integration. A two-mode squeezed
quantum microcomb comprising 34
quantum modes is measured with approximately 3 dB squeezing. Our work establishes a scalable architecture for fully integrated squeezed-light
quantum photonic systems, unifying
quantum-state generation, processing, and detection on a single chip.
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All authors Haoran Chen, Benjamin Westcott, Fatemehsadat Tabatabaei, Xiangwen Guo, Shuman Sun, Zijiao Yang, Gedalia Y. Koehler, Beichen Wang, Shadrach Sarpong, Steven Bowers, Olivier Pfister, Andreas Beling, Xu Yi
Plasma Physics
Flow-thermochemistry coupling governs pressure-dependent CO$_2$ conversion in vortex-stabilized microwave plasma reactors: Insights from three-dimensional CFD modeling
Qinghao Shen, Cas van Deursen, Pieter Willem Groen et al. (+2 more)
In this work, a three-dimensional computational fluid dynamics model is developed for a
vortex-stabilized microwave CO$_2$
plasma reactor operating over the pressure range of 100-400 mbar. The model combines experimentally constrained, emission-based
plasma sizes and volumetric heat-source distributions with thermally dominated finite-rate heavy-particle chemistry for a multi-component mixture. Turbulent flow and transport are described using the SST k-omega model. The model reproduces the measured radial gas-temperature profiles in the
plasma core and the non-monotonic pressure dependence of CO$_2$ conversion, including a maximum at 150 mbar and a pronounced decrease at 400 mbar. A
vortex-driven recirculation region redistributes gas upstream. Turbulent mixing and cooling are strongest near the upper reactor boundary, but their contribution decreases as pressure increases. The pressure dependence of conversion is determined by the competition between CO$_2$ dissociation and CO recombination. CO$_2$ direct dissociation reaction dominates in the high-temperature
plasma core, whereas O-assisted conversion reaction contributes near the
plasma edges and in the surrounding hot region. At 150 mbar, enhanced CO$_2$ dissociation is accompanied by limited CO loss, resulting in the highest conversion. With pressure increasing to 400 mbar, slower cooling and more frequent three-body collisions promote CO recombination in the afterglow, causing more than 60% of the CO formed near the
plasma to be lost downstream. Moreover, additional CO loss occurs in the upper region of the reactor at higher pressures because of the reduced cooling rate.
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All authors Qinghao Shen, Cas van Deursen, Pieter Willem Groen, Lex Kuijpers, Mauritius C.M. van de Sanden
Quantum Physics
Ion trap on borosilicate substrate with integrated femtosecond-laser-written waveguide
Jakob Wahl, Alexander Zesar, Philipp Hurdax et al. (+9 more)
We present an ion-trap platform on borosilicate glass with an integrated femtosecond-
laser-written waveguide for on-chip light delivery. The optical layer is physically separated from the electrode substrate and bonded atop the trap, remaining compatible with silicon-based integration. We engineer single-mode low-loss guidance at 729 nm with tunable mode-field diameter and achieve low-loss curved waveguides down to a radius of
curvature of 6 mm. We also extend single-mode operation to a wavelength of 405 nm. The fabrication process is compatible with the industrial fabrication of a single-metal-layer surface-electrode trap, including active fiber
alignment and bonding. We validate the platform in a cryogenic trapped-ion system with $^{40}$Ca$^+$, demonstrating trapping, shuttling the ion to a zone in front of the waveguide, and coherent operations driven by 729 nm light delivered through the integrated waveguide. We characterize the effect of the exposed dielectric on the ion and measure stray electric fields that show slow drift at a timescale of hours. The architecture is compatible with hybrid micro-optics (e.g. pick-and-place lenses) to realize single ion addressing and provides a robust, scalable route to integrated light delivery for trapped-ion devices.
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All authors Jakob Wahl, Alexander Zesar, Philipp Hurdax, Marco Schmauser, Victoria Schwab, Michael Pasquini, Marco Valentini, Clemens Rössler, Thomas Monz, Bernhard Lamprecht, Klemens Schüppert, Philipp Schindler
General Relativity and Quantum Cosmology
Long-term 3+1 simulations of primordial black hole formation during radiation domination
Zhuan Ning, Rong-Gen Cai, Shao-Jiang Wang et al. (+1 more)
We develop an efficient three-dimensional numerical-relativity framework for
primordial black-hole (PBH) formation from superhorizon
curvature perturbations in a radiation-dominated Universe. We implement flux-conservative relativistic hydrodynamics in the adaptive-mesh-refinement code GRChombo and introduce a cosmologically scaled Gamma-driver that allows the
cosmic-time step to grow in proportion to the scale factor. For a representative long-term simulation, the scaled driver preserves the apparent-horizon mass
evolution and constraint behavior while reducing the number of coarse-level advances by a factor of approximately $94$ relative to the standard driver. We also construct a conformal-time version of the moving-puncture gauge as an independent check. Applying the framework to a spherical Gaussian
curvature profile, we find a collapse threshold $0.79578 < \mu_c < 0.79580$ and a critical exponent $\gamma \simeq 0.3559$, consistent with previous spherically symmetric results. We further fit the late-time PBH mass growth to the Zel'dovich–Novikov
accretion law, demonstrating that the code can follow both near-critical collapse and long-term post-formation
evolution in three dimensions. The framework provides a foundation for future studies of PBH formation beyond spherical
symmetry.
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All authors Zhuan Ning, Rong-Gen Cai, Shao-Jiang Wang, Chul-Moon Yoo
Quantum Physics
Counterexamples to the Tensorization Property of Strong Data Processing Inequalities for Quantum Divergences
Yu Cao
In information theory, the data processing inequality is a fundamental property that describes the loss of information through noisy channels. A more refined description is given by the strong data processing inequality (SDPI) for a fixed channel and a full-rank reference state. In classical information theory, the strong data processing inequality tensorizes for a large family of $f$-divergences. However, its
quantum counterpart remains largely unexplored. Tensorization of SDPI has previously been shown only for some special cases, and whether it holds more generally for
quantum divergences still remains open. In this work, we report two negative results: the tensorization property fails for certain
quantum chi-square divergences, and it also does not hold for the
quantum relative
entropy.
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Optics
Ultrafast Tracking of the Spallation Layer in Bulk Gold, Aluminum, and Steel
Nicolas Thomae, Julian Vollmann, Julian Freundel et al. (+3 more)
Extreme manufacturing with ultrashort-pulse (USP)
lasers at the physical limit of precision and efficiency requires understanding ablation dynamics on the picosecond-to-nanosecond timescale. Pump-probe reflectometry (PPR) provides direct access to photomechanical spallation through Newton ring (NR) interference, but this signature vanishes when the spallation layer becomes optically opaque or the ablated material strongly attenuates the probe. Here, we combine PPR with phase-sensitive interferometric pump-probe (PPI) measurements to track the spallation layer in bulk steel, aluminum, and gold. PPI resolves the propagating layer even when the reflected probe signal is suppressed by >95%. Joint PPR/PPI analysis with transfer-
matrix modelling (TMM) yields spallation layer thickness, vapor layer absorption, and the layer disintegration times. These quantities are key determinants of the energy coupling of subsequent pulses in GHz burst processing.
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All authors Nicolas Thomae, Julian Vollmann, Julian Freundel, Maximilian Spellauge, David Redka, Heinz P. Huber