History and Philosophy of Physics
Is Black Hole Evaporation Prediction Friendly?
Dominic John Ryder
Manchak and Weatherall (2018) formulate the black hole information paradox as a failure of predictability in black hole evaporation spacetimes, diagnosed by non-global hyperbolicity. I offer a strategy for resolving this paradox. I argue that failures of predictability in black hole evaporation are not well diagnosed by non-global hyperbolicity. I then consider two weakenings of global hyperbolicity: prediction and retrodiction friendliness, the failure of which could ground a new paradox. However, deidealized black hole evaporation models can be prediction and retrodiction friendly. Therefore, the information paradox cannot be based upon failures of global hyperbolicity, nor either retrodiction or prediction unfriendliness.
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General Relativity and Quantum Cosmology
Prospects of electromagnetic follow-up of neutron star-black hole mergers in the LIGO-India era
Yogita Kumari, Kanchan Soni and Sanjit Mitra
Neutron star-black hole (NSBH) mergers are promising multimessenger sources, but only a subset is expected to produce detectable electromagnetic (EM) counterparts, depending on the binary mass ratio, black hole (BH)
spin, and
neutron star (NS) equation of state (EoS). We investigate the prospects for detecting kilonova counterparts to NSBH mergers in the LIGO-India era using the Vera C. Rubin Observatory (Rubin). We simulate GW230529-motivated NSBH populations with two effective
tidal deformability ranges, estimate gravitational-wave detections for the LHV (LIGO-Livingston, LIGO-Hanford, Virgo) and LHVA (LHV with LIGO-India at Aundha) detector networks, and model the detectability of the associated kilonova emission with Rubin. We find that adding LIGO-India approximately doubles the number of EM follow-ups, primarily by increasing the duty cycle and reducing the median sky-localization area, and notably increases the number of such detections at large distances. For fixed-exposure strategies, the EM detection rate saturates at exposure times of a few hundred seconds, reflecting the trade-off between depth and sky coverage. We therefore introduce an event-specific exposure-time optimization strategy based on the expected counterpart brightness and sky-localization area. With this strategy, the expected NSBH GW+EM detection rate per year is 4.19(-3.58,+9.66) for the optimistic and 0.79(-0.68,+1.83) for the conservative population with the LHVA network, compared to 1.46(-1.25,+3.37) and 0.27(-0.23,+0.62), respectively, for LHV. The required Rubin follow-up time remains within the expected Target-of-Opportunity allocation. These results show that in the next decade, a few such NSBH follow-ups may take place, with a fraction of them in the
redshift range of about 0.1-0.2, which will not only be useful for measuring the Hubble constant but can also help us in probing the Hubble parameter.
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Materials Science
Dimensional Control of Excitonic Interactions in Exfoliated 2D Molecular Crystals
Jonghyun Son, Seonghyun Koo, Daniel Yim et al. (+17 more)
Excited states in molecular
crystals depend on intermolecular coupling, charge-transfer interactions, dielectric screening and molecular packing. How reduced dimensionality modifies these interactions when molecular packing structure is preserved remains unclear. Here we demonstrate that tetracene and three other molecular
crystals can be mechanically exfoliated into mono-, few- or multilayer flakes, exploiting the top-down approach established for inorganic layered materials. Electron diffraction confirms that exfoliated tetracene retains long-range crystalline order and nearly bulk-like in-plane
lattice parameters. This structural fidelity enables systematic thickness-dependent spectroscopy with limited changes in molecular packing. With decreasing thickness, the Davydov splitting diminishes, whereas the Stokes shift increases to nearly three times its bulk-like value, indicating enhanced excited-state relaxation. The photoluminescence 0-0/0-1 intensity ratio also rises, suggesting greater
exciton delocalization. Compared with exfoliated tetracene, assembly-grown
crystals exhibit
lattice contraction and larger Davydov splitting. Analysis within the Frenkel-charge-transfer mixing framework qualitatively accounts for the Davydov-state energy shifts and splitting in terms of molecular packing, intermolecular coupling and dielectric screening. Our results show that intermolecular interactions, excited-state relaxation and
exciton coherence can be systematically tuned by varying layer number, demonstrating the feasibility and utility of extending dimensional control of inorganic 2D materials to molecular
crystals.
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All authors Jonghyun Son, Seonghyun Koo, Daniel Yim, Sangjin Han, Dong-Hwan Yang, Gi-Yeop Kim, Kihyun Lee, Jieun Yeon, Hye Soo Kim, Eunbeen Jeon, Minji Ko, Minhee Choe, Kenji Watanabe, Takashi Taniguchi, Hee Cheul Choi, Kwanpyo Kim, Si-Young Choi, Seogjoo J. Jang, Hyungjun Kim, Sunmin Ryu
Mesoscale and Nanoscale Physics
Apparent Zero-Momentum Signals from Magnon–Magnon Interference in Near-Field Spin-Wave Imaging
Julien Berthomier, Romain Lebrun, Vincent Cros et al. (+3 more)
Spatially resolved measurements of coherent waves are commonly read as direct maps of the underlying eigenmode spectrum. We show that this interpretation fails in near-field imaging of multimode
spin-wave transport. Scanning nitrogen-vacancy magnetometry of yttrium iron garnet reveals pronounced apparent low-wave-vector signals at frequencies for which no propagating
spin-wave mode exists. By tuning the probe-sample distance and modeling the anisotropic near-field response, we identify their origin as coherent mixing between directly excited Damon-Eshbach waves and defect- or transducer-scattered
spin waves: the measured signal acquires spatial
Fourier components at the difference wave vector $\mathbf{k}_{\mathrm{exc}}-\mathbf{k}_{\mathrm{scat}}$, which can vanish even though both constituent waves carry finite momentum. These results establish that near-field spectra of coherent excitations are interferometric field spectra rather than eigenmode maps, providing both a caution and a framework for identifying scattering processes in nanoscale magnonic devices.
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All authors Julien Berthomier, Romain Lebrun, Vincent Cros, Jamal Ben Youssef, Karim Bouzehouane, Abdelmadjid Anane
High Energy Astrophysical Phenomena
Time-Correlated Profile Variability in the MeerKAT Pulsar Timing Array
Bhavnesh Bhat, Michael J. Keith, E. Carli et al. (+2 more)
Long-term pulse-profile variability has emerged as a potentially important source of uncertainty for high-precision
pulsar timing, as changes in the integrated pulse shape can bias pulse times of arrival and affect the sensitivity of
pulsar timing arrays to nanohertz gravitational waves. We present a systematic search for long-term pulse-profile variability in the six-year MeerKAT
Pulsar Timing Array data, analysing observations of 84 millisecond
pulsars using a two-dimensional Gaussian-process framework to identify coherent temporal and phase-dependent profile
evolution. We detect pulse-profile variability in 18
pulsars. Using the frequency dependence of the observed profile
evolution together with scattering simulations, we classify six
pulsars as exhibiting chromatic variability consistent with interstellar scattering, while the remaining twelve display predominantly frequency-independent behaviour suggestive of intrinsic changes in the
pulsar emission process. Correcting for the S/N-dependent detection bias, we infer that intrinsic profile variability is substantially more common than implied by the detected sample, with at least 40 per cent of millisecond
pulsars exhibiting intrinsic profile variability at the 95 per cent credible level. Motivated by the association between pulse-profile variability and
spin-down-rate ($\dot{\nu}$) switching in canonical
pulsars, we search for corresponding $\dot{\nu}$ variations but find no statistically significant detections. Simulations indicate that the expected variations remain below the sensitivity of current
datasets, although unresolved changes may contribute to weak achromatic timing noise. These results suggest that long-term pulse-profile variability may be common among millisecond
pulsars and should be explicitly modelled in future high-precision
pulsar-timing experiments.
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All authors Bhavnesh Bhat, Michael J. Keith, E. Carli, R. M. Shannon, Benjamin W. Stappers
Applied Physics
Spectral Geometry and Dispersion-Constrained Projection of Diffusive Fields
Pengfei Zhu, Julien Lecompagnon, Philipp Daniel Hirsch et al. (+1 more)
Diffusive fields obey operator-imposed relations between spatial structure and temporal decay, yet conventional spectral filtering selects components primarily according to frequency or wavenumber magnitude. Here we show that the
diffusion operator defines a spectral geometry in the joint space of spatial wavenumber and modal decay rate, where physically admissible modes occupy the
manifold $\eta=\alpha|\mathbf{k}|^2$. This geometry separates spectral scale from physical consistency: high-wavenumber modes can remain
diffusion-consistent, whereas lower-wavenumber modes can violate the governing dynamics. We exploit this distinction by introducing an operator residual and a finite-width soft projection that selects spectral components according to their distance from the
diffusion manifold rather than their spectral magnitude. Numerical studies demonstrate robust recovery under noise, diffusivity mismatch, and finite acquisition, and reveal a consistency–retention tradeoff governed by the
manifold width. Photothermal experiments further confirm that the projection suppresses off-
manifold spectral content while retaining the dominant thermal response. These results establish operator consistency as a spectral-selection principle for diffusive fields and provide a
geometric framework for physics-informed processing of dissipative systems.
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All authors Pengfei Zhu, Julien Lecompagnon, Philipp Daniel Hirsch, Mathias Ziegler
Instrumentation and Detectors
A Six-Quadrupole Diamagnetic Suspension Architecture for Ultra-Sensitive Space Accelerometry
Marco Pisani, Edoardo Dalla Ricca, Carlo Paolo Sasso et al. (+1 more)
This paper proposes a novel inertial sensor based on a solid diamagnetic cubic test mass passively suspended by a symmetric configuration of six
magnetic quadrupoles. Designed specifically for microgravity environments, this system eliminates the mechanical noise and hysteresis inherent in elastic suspensions, as well as the complexity associated with electrostatic suspension systems. We provide an analysis of the
magnetic intrinsic noise floor imposed by eddy current damping, alongside ground-based preliminary experimental results demonstrating potential sensitivities in the order of the $10^{-10} \text{ m/s}^2/\sqrt{\text{Hz}}$ regime.
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All authors Marco Pisani, Edoardo Dalla Ricca, Carlo Paolo Sasso, Massimo Zucco
Astrophysics of Galaxies
The magnetic field in M16: new results from the JCMT BISTRO survey
R.M.R. Tulloh, D. Ward-Thompson, J. Karoly et al. (+2 more)
We present a study of the
magnetic field (B-field) in the Eagle Nebula (M16) using data from the James Clerk Maxwell
Telescope (JCMT) B-fields In
STar-forming Region Observations (BISTRO) survey. We extend our previous study of the well-known `Pillars of Creation' region of the nebula to study two other structures in the region, the `Spire' and the bright-rimmed cloud (BRC) known as `SFO30'. These structures show similar B-field morphologies to the Pillars. We calculate B-field strengths using the Davis-Chandrasekhar-
Fermi (DCF) method and thereby estimate the
magnetic potential energy in each of these regions for comparison with the local gravitational, turbulent and thermal energies, as well as the pressure energy of the shocks from nearby O-type
stars. We find approximate equipartition between the energies supporting the regions and those tending towards collapse, with the B-field support playing a significant role. This agrees with our earlier hypothesis that B-fields help support pillar-like structures in molecular clouds and make them longer-lived than they would otherwise have been.
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All authors R.M.R. Tulloh, D. Ward-Thompson, J. Karoly, J.M. Kirk, K. Pattle
Plasma Physics
High-charge, highly polarized positron beams generated from a laser-driven nanowire-array target
De-Sheng Zhang, Cui-Wen Zhang, Kun Xue et al. (+4 more)
The generation of high-charge, highly polarized positron beams in the interaction of a linearly polarized
laser pulse with a nanowire-array target is investigated. Here,
laser-driven electrons emit high-energy
photons through nonlinear Compton scattering (NCS), which subsequently produce electron–positron pairs through the nonlinear Breit–Wheeler (NBW) process. We model this interaction using two-dimensional
spin-resolved
quantum electrodynamics particle-in-
cell (QED-PIC)} simulations. At positron birth, the sign of $S_z$ is statistically correlated with that of the local $B_z$. The spatiotemporal field structure arising from the
laser–nanowire interaction strengthens the correlation between the birth
spin sign and the direction of the subsequent transverse Lorentz impulse, thereby limiting cancellation between opposite-
spin contributions at a given angle. The results show that the average polarization degree reaches $|\bar S_z|\approx0.46$, and the positron charge satisfying $|\bar S_z|>0.3$ is approximately $308\,\mathrm{nC}$. Parameter scans reveal that the high-polarization positron charge is maximized at intermediate target densities and nanowire periods. Such a source could enable polarization-sensitive studies of strong-field QED and
spin-dependent phenomena in high-energy and materials physics.
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All authors De-Sheng Zhang, Cui-Wen Zhang, Kun Xue, Feng Wan, Xue-Ren Hong, Jian-Xing Li, Bai-Song Xie
Astrophysics of Galaxies
The Dense Gas Structures Around MMS 2/OMC-3 Traced by C$^{18}$O Emission
Yuhua Liu, Satoko Takahashi and Masahiro N. Machida
We report the Atacama Large Millimeter/submillimeter Array observations of 1.3 mm continuum, C$^{18}$O ($J=2$$-$$1$), and N$_{2}$D$^{+}$ ($J=3$$-$$2$) toward the millimeter multi-system MMS 2 in the Orion Molecular Cloud-3 region, at an angular resolution of 1.59" ($\sim$620 au). MMS 2 is in the flat-spectrum phase, with its protostars in the late stage of the main
accretion phase. We detect the centrally condensed structures traced by C$^{18}$O emission associated with the 1.3 mm continuum sources MMS 2-North and MMS 2-South, which are spatially resolved and unresolved, respectively. The estimated diameter and mass of the centrally condensed structure associated with MMS 2-North are 1.64" ($\sim$640 au) and 3.0$\times$10$^{-4}$M$_{\odot}$, respectively. We also detect an extended structure traced by C$^{18}$O emission associated the circumbinary envelope at scale of 5.70" ($\sim$2240 au) with an estimated gas mass of 1.4$\times$10$^{-2}$$M_{\odot}$. In addition, we detect a filamentary structure traced by N$_2$D$^+$ emission to the south of MMS 2, which is spatially offset from the C$^{18}$O emission. This offset may be attributed to the influence of the warm surrounding environment.
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Earth and Planetary Astrophysics
JWST-SUPER I: New insights into irradiated warm Neptunes atmospheres from MIRI observations of HD 106315 c
A. Dyrek, R. Waters, S.-M. Tsai et al. (+17 more)
Sulphur-bearing molecules have recently emerged as powerful tracers of atmospheric photochemistry in
exoplanets observed with JWST. In several warm
giant planets, SO$_2$ has been detected as a product of UV-driven chemical processing, suggesting a close connection between
stellar irradiation, atmospheric
metallicity, and sulphur chemistry. Whether these trends extend to Neptune-mass
planets orbiting hotter
stars remains largely unexplored. We investigate the atmospheric composition of the warm Neptune HD 106315 c, a Neptune-mass
planet orbiting an F-type host
star and subjected to a strong ultraviolet (UV) irradiation environment. Here, we report the low-resolution transmission spectrum between 5 and 12 $\mu$m of HD 106315 c obtained with the MIRI Low-Resolution Spectrometer on-board JWST. Our work also includes re-analysis of archival data from HST WFC3 G141 mode of HD 106315 c, as well as contemporaneous XMM and Swift monitoring of the
star in the UV and X-ray wavelength ranges. Together with the archival HST WFC3 data, we detect H$_2$O and find tentative evidence for NH$_3$, retrieving abundances of $\log_{10}$(H$_2$O)$=-1.40^{+0.40}_{-0.74}$ and $\log_{10}$(NH$_3$)$=-2.47^{+0.57}_{-0.89}$, together with an isothermal terminator temperature of $747^{+150}_{-155}$ K. We place stringent upper limits on CH$_4$, SO$_2$, and CS$_2$, finding no robust evidence for any sulphur-bearing species despite the intense irradiation received by the
planet. The inferred water abundance implies a strongly metal-enriched atmosphere. Elevated intrinsic temperatures can reconcile the non-detections of CH$_4$ and CS$_2$ through carbon–sulphur coupling, while the absence of SO$_2$ points toward a reduced atmospheric sulphur inventory or a near-
solar to mildly enhanced C/O ratio, and places HD 106315 c near the transition between sulphur-rich and sulphur-poor chemical regimes.
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All authors A. Dyrek, R. Waters, S.-M. Tsai, M. Holmberg, B. Edwards, J. Pye, M. Güdel, N. Crouzet, R. van Gompel, J. Polman, F. Ardevol Martinez, D. Barrado, W. De Gruijter, Th. Henning, S. Kendrew, N. Khorshid, Y. Miguel, M. Min, M. Morales-Calderon, M. Topinka
Instrumentation and Methods for Astrophysics
First Very Long Baseline Interferometry Fringe Detection at 690GHz
Ming-Tang Chen, Geoffrey B. Crew, Dan Bintley et al. (+42 more)
We report the first very long baseline interferometry (VLBI) experiment conducted in the 690 GHz atmospheric window. On 2024 November 21, observations with the Atacama Large Millimeter/submillimeter Array, the Atacama Pathfinder EXperiment (APEX), and the James Clerk Maxwell
Telescope (JCMT) were carried out using ALMA's newly developed Band 9 phasing capability. Fringes were detected on the ALMA-APEX baseline during a scan of the
quasar J0423-0120, with a signal-to-noise ratio of ~12 and useful fringe recovery over solution intervals of order tens of seconds, representing the highest-frequency ground-based VLBI fringe detection reported to date. No fringes were found on the ALMA-JCMT baseline, despite excellent weather conditions, consistent with sensitivity predictions and supporting baseline performance models. The ALMA Phasing System maintained stable phasing at Band 9 for ~1-2 minutes before gradually degrading, indicating limitations under these observing conditions. Our analysis shows that, under excellent weather conditions, 690 GHz VLBI can still support fringe recovery over short solution intervals, despite rapid atmospheric phase fluctuations at these frequencies. This work validated key elements of near-terahertz VLBI operation and establishes a technical foundation for routine observations in the 690 GHz atmospheric window.
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All authors Ming-Tang Chen, Geoffrey B. Crew, Dan Bintley, Alan Roy, Keiichi Asada, Johnson Han, Kuan-Yu Liu, Chin-Shin Chang, Andrea McClöskey, Yiqing Song, Vincent Fish, Michael Lindqvist, Satoki Matsushita, Lynn D. Matthews, Hugo Messias, Jan F. Wagner, Ue-Li Pen, Derek Kubo, Teddy Huang, Philippe Raffin, Chih-Wei L. Huang, Pierre Martin-Cocher, Geoffrey C. Bower, Patrick Koch, Lisa Kewley, Timothy Norton, Nimesh Patel, Paul T. P. Ho, Per Friberg, Izumi Mizuno, Akil Marshall, Andrey M. Baryshev, Heino Falcke, Thomas Greve, Jacques Lepine, Manuel Fernández López, Silvina Cichowolski, Carlos Valotto, Ciriaco Goddi, Guillermo Giménez de Castro, Fátima Salete Correra, Marianne Vestergaard, Jes Kristian Jørgensen, Martin E. Pessah, Roman Gold
Astrophysics of Galaxies
A Theoretical Study of the Stellar Parameters and Surface Nucleosynthesis of the Extremely Metal-Poor RGB Giant BD$-18^{\circ}$5550 - Part I: Effects of $\alpha$-enhancement and Internal Mixing
Mrinmay Medhi, Upakul Mahanta, Swapnajyoti Sarma et al. (+1 more)
We present a detailed
stellar evolution study of BD$-18^{\circ}$5550, an extremely metal-poor red
giant star in the
Galactic halo. Such
stars are among the oldest known objects and preserve chemical signatures of the earliest stages of
Galactic history. BD$-18^{\circ}$5550 exhibits $\alpha$-enhancement, $\rm[\alpha/Fe]=+0.4$, typical of Population II
halo stars, with enhanced abundances of oxygen, magnesium, and other $\alpha$-elements relative to iron. Using the MESA
stellar evolution code, we perform the first direct determination of its mass, age, radius, and luminosity by simultaneously fitting eight observed
stellar properties and multiple chemical abundance ratios. Our analysis yields a current mass of $\rm M=0.76,M_{\odot}$, radius of $R=38.4,R_{\odot}$, luminosity of $\log L=2.8,L_{\odot}$, and an age of $t=11.87$ Gyr, with a 7-fold improvement in age precision. The model reproduces all observed constraints, supporting our treatment of
stellar physics,
nuclear reactions, and internal mixing. We further investigate the predicted surface chemical composition up to iron and compare it with observations. The surface abundances of elements up to iron remain essentially unchanged throughout the
evolution, while nitrogen shows gradual enrichment, indicating the onset of mixing processes at intermediate RGB stages. The preservation of the other surface abundances provides a valuable window into the chemical conditions of the early
Galactic environment. Our results establish BD$-18^{\circ}$5550 as a
benchmark star for constraining
stellar evolution and early
Galactic chemical
evolution. Its derived age places it among the oldest
stars in the Milky Way, providing important constraints on the epoch of early
star formation and the initial assembly and
evolution of our
Galaxy.
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All authors Mrinmay Medhi, Upakul Mahanta, Swapnajyoti Sarma, Apurba Talukdar
Solar and Stellar Astrophysics
Studies of Two Post Common Envelope Binary Stars
Chris Koen and Alexei Kniazev
New time series photometry of the short period ($P<0.2$~d) binary
stars ZTF~J032906.36+070408.3 (ZTF~0329) and ATO~J090.7238+00.5996 (ATL~0602) is presented. The primary (hotter)
stars in both systems are white
dwarfs, while the cooler
stars are M
dwarfs. Archival photometry and new and archival spectra are used to derive the temperatures of the components in the two binaries. Both are single-lined binaries. Velocity curves are fitted to radial velocity measurements of the red
dwarfs and used to place lower limits on the masses of the white
dwarfs. New and archival time series photometry show
evolution in the shapes of the light curves of both
stars. Spectra of ZTF~0329 show an excess of radiation in the $R_C$ band which is ascribed to electron cyclotron radiation, suggesting that the
star is a low
accretion rate polar. Satisfactory model fits to the multi-filter light curves of ATL~0602 require the presence of cool spots on the red component of the binary. The latter
star exhibits a variety of velocities associated with Balmer and Ca~II emission lines within individual spectra.
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Statistical Mechanics
Quantifying cell shape and density fluctuations in epithelial tissue in vivo
Jake Turley, Helen Weavers, Paul Martin et al. (+2 more)
Controlling changes in
cell shape are crucial for many biological processes, such as tissue development and wound healing. Tissues typically are heterogeneous with a variety of
cell shapes and sizes. Of particular interest are local deviations from an average
cell shape and size. These fluctuations may extend and transmit across tissues, potentially offering valuable insights into tissue characteristics such as variations in effective "stiffness" or
rigidity. In this study, we present a theoretical framework that captures the dynamics of epithelial
cell shapes within tissue, incorporating both their average behaviour and fluctuation patterns. We model
cells as interacting soft ellipsoids of varying size and aspect ratio. Coarse-graining our model, we obtain a set of continuum
stochastic differential equations from which we derive spatial-temporal correlation functions. These correlation functions fit with our experimental data from the developmental process of the Drosophila pupal wing. From the correlation functions, critical parameters representing active
cell shape changes and effective tissue "stiffness" can be determined.
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All authors Jake Turley, Helen Weavers, Paul Martin, Isaac V. Chenchiah, Tanniemola B. Liverpool
Mesoscale and Nanoscale Physics
Photo-induced Wavelength-tuning of Telecom-band Quantum Dot Nanowires Embedded in a Phase Change Material
Evangelos Sotiropoulos, Philippe Regreny, Matthieu Bugnet et al. (+4 more)
Scalable
quantum-photonic technologies require spatially separated emitters to emit at the same wavelength, yet epitaxially grown
quantum dots naturally exhibit emitter-to-emitter variations in their emission energies. Here, we demonstrate a contact-free post-growth tuning approach for InAs
quantum dots embedded in InP nanowires using the photo-induced transformation of an amorphous Sb2S3 shell. This photoinduced effect leads to a progressive relaxation of the strain imposed on the InP core, enabling controlled spectral tuning of the
quantum-dot emission. The effect is observed both at room temperature and under cryogenic conditions for
quantum dots emitting in the O-band of the telecommunications spectrum. Strain-induced
redshifts of approximately 7 meV at room temperature and 28 meV under cryogenic conditions are observed, respectively. The use of an amorphous chalcogenide shell therefore provides a route to achieve local wavelength tuning at the single
quantum-dot-in-a-nanowire level after growth. This approach could enable spectrally matched emitters for scalable
quantum-photonic architectures.
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All authors Evangelos Sotiropoulos, Philippe Regreny, Matthieu Bugnet, Nicholas P. Blanchard, Sébastien Cueff, José Penuelas, Nicolas Chauvin
High Energy Physics (Theory) · Cross-listed from math.GT
Computation of unknotting numbers: which knot breaks the Bernhard-Jablan Conjecture
Seong-Jin Lee
We determine $2,540$ unknotting numbers of
prime knots with at most $13$ crossings, that are unknown in the KnotInfo snapshot of 9 September 2026. The lower-bound calculations use Heegaard Floer correction-term obstructions and Greene's spanning-tree model. We also give explicit crossing-change constructions for upper bounds. For $959$ alternating
knots with range $[2,3]$, we verify that no crossing change in a minimal diagram gives a
knot of unknotting number one. We determine the unknotting numbers of all four
knots in Brittenham and Hermiller's construction and thereby identify 13n3370 as an explicit counterexample to the original Bernhard-Jablan
conjecture.
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Quantum Physics
When Does a Quantum Speedup Survive End-to-End?
Pablo Herrero Gómez, Antonio Jimeno Morenilla, David Muñoz Hernández et al. (+1 more)
Primitive
quantum speedups are interface-relative: they depend on the input access used to run the primitive and on the output contract used to consume its state or samples. This paper introduces a transcript-level admissibility relation \(A_M\preceq_{\mathrm{int}}A_Q\), defined relative to the declared implementation package of the
quantum interface. It identifies which adaptive classical access transcripts that same package licenses, with all setup, transcript-generation, and precision overheads charged. The main application is an operational audit for normalized-Betti estimation in clique-complex TDA, separating three declared-interface regimes. Reversible indexed simplex interfaces certify matched classical simplex sampling and local
Laplacian row access by evaluating their reversible routines on single computational branches. Membership-based preparations induce a rejection route of overhead \(\binom{n}{k+1}/|S_k|\). Abstract spectral or block-encoding interfaces require an accompanying implementation package, transcript reduction, or shared representation. Under the indexed certificate and interface closure, the end-to-end cost is fixed by the imported
estimator's spectral dependence on the gap \(\gamma\); the concretely realized bounded-treewidth family already admits exact \(\mathrm{poly}(n)\) classical Betti computation by rank over \(\mathbb{Q}\). A low-rank separation supports the role of access and output contracts.
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All authors Pablo Herrero Gómez, Antonio Jimeno Morenilla, David Muñoz Hernández, Higinio Mora Mora
Quantum Physics
Simple QKD keyrate computations from tangent-line bounds
Jun Hui Goh and Ernest Y. -Z. Tan
Recent work in
quantum key distribution (QKD) has yielded finite-size keyrates based on convex optimisation problems, using the framework of
entropy accumulation. Multiple solvers have been developed to address these optimisations in recent years, but have been based on a somewhat elaborate framework using sophisticated
algorithms, in order to accommodate a broad range of QKD protocols. In this work, we note that for basic QKD protocols such as
qubit BB84, the keyrates can be easily computed using off-the-shelf solvers instead, by obtaining suitable tangent lines to lower bound terms in the objective function. We compute the resulting finite-size keyrates and compare them to previous work. Moreover, we extend this approach to the six-state protocol, by deriving closed-form expressions for the single-round Rényi
entropies in the protocol. This should facilitate subsequent study of the six-state protocol via
entropy accumulation.
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Atomic Physics
Miniaturized vacuum package for magneto-optical trapping of strontium
Julian Pick, Eric Henker, Florian Löwinger et al. (+17 more)
Quantum sensors, like optical
lattice clocks, undergo a continuous development from lab-based towards mobile systems. A key aspect in the miniaturization of the experimental setups is the development of compact atom sources. Conventional atom sources for alkaline-earth-like elements consist of a high-power oven and a six-beam magneto-optical trap (MOT) inside of
vacuum chamber with extensive flanges, viewports and electrical feedthroughs. Here we present a highly compact
vacuum package utilizing key technologies for future
quantum sensor systems: A chip-based low-power atomic oven, a planar grating MOT chip, and a miniaturized
vacuum pump all held inside an additively manufactured titanium
vacuum chamber, featuring custom-sized
vacuum flanges. In this miniaturized setup, spanning a volume of only 750 ml, we trap up to $10^5$ Sr atoms in a MOT, requiring an oven heating power below 1 W.
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All authors Julian Pick, Eric Henker, Florian Löwinger, Rick Vogt, Sebastian Hüttl, Andreas Trützschler, Julia Voß, Simon Hirt, Malte Schulz-Ruhtenberg, Aleksandra Buchta, Alexander Kassner, Folke Dencker, Marc Wurz, Stephan Hannig, Simone Callegari, Saskia Bondza, Jens Kruse, Tobias Leopold, Roman Schwarz, Carsten Klempt
Instrumentation and Detectors
Operation of a negative ion gas time projection chamber without electronegative fill gases
Lachlan J. McKie, Lindsey J. Bignell, Nicholas Adams et al. (+3 more)
The high fidelity reconstruction of particle tracks in micropatterned gaseous time projection chambers renders this technology ideal for future rare-event searches, including direction-sensitive dark matter experiments. Large drift distances are typically required for such experiments, so that the overall spatial resolution is limited by
diffusion. Negative ion drift exhibits lower
diffusion than electron drift and is thus an attractive option for realising a large-scale detector. The use of electronegative gases to create negative ions introduces technical challenges, most notably a reduction in gain when compared to conventional gas mixtures. In this study, we demonstrate a new method for negative ion generation via dissociative electron attachment using the conventional molecular fill gas CF$_4$. Our optical measurements of negative ion drift indicate electron attachment lengths of $<$1 mm and comparable gain to electron avalanches. The individual negative ion avalanches were also time-resolved, allowing the number of ions reaching the readout to be counted. We measure an improved energy resolution by single ion counting, relative to an integrated electron avalanche signal measured under identical gain conditions.
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All authors Lachlan J. McKie, Lindsey J. Bignell, Nicholas Adams, Victoria U. Bashu, Ferdos Dastgiri, Gregory J. Lane
Quantum Physics
Minimax games for quantum channel discrimination
Kun Fang, Michael X. Cao, Hao-Chung Cheng et al. (+2 more)
Quantum channel discrimination is a primitive task for identifying, verifying, and benchmarking
quantum dynamics. Previous studies have primarily considered either the best-case tester-input setting or the worst-case jammer-input setting. Here, we introduce a game-theoretic framework in which both the tester and jammer control separate inputs. Combining three input structures, characterized by whether the tester and jammer use entangled inputs or IID inputs across channel uses, with four information patterns, determined by the visibility of the jammer's strategy and its knowledge of the true hypothesis, yields twelve game models. We provide exact finite blocklength hypothesis testing characterizations of all twelve models in terms of nine minimax hypothesis testing divergences and derive their asymptotic Stein exponents. Notably, for entangled jammers, neither the visibility of the jammer's strategy nor its knowledge of the true hypothesis affects the asymptotic Stein exponent, whereas the information pattern remains consequential for IID jammers. As an example, we study the discrimination of a general channel from a replacer channel and show that all asymptotic Stein exponents coincide with the same additive, single letter quantity. We further develop a general argument that upgrades achievability results to strong converse results, thereby establishing strong converse properties for several game models, resolving an open problem in composite hypothesis testing posed by Berta et al. [Commun. Math. Phys. 385, 55 (2021)], and strengthening several recent results of Lami [arXiv:2510.06340]. The framework and techniques developed here may support future studies of
quantum information tasks involving competing roles.
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All authors Kun Fang, Michael X. Cao, Hao-Chung Cheng, Li Gao, Masahito Hayashi
Quantum Physics
Robust Device-Independent Certification of Boolean-Phase Gates
Yunguang Han, Xingyuan Bu, Aleksandra Gočanin et al. (+1 more)
Device-independent certification of a
quantum gate requires the input and output tests to identify the same reference
qubits. Self-testing the output Choi state alone does not guarantee this consistency. We develop a robust certification scheme for Boolean-phase gates, a broad family of computational-basis diagonal gates specified by Boolean functions. Boolean derivatives convert the target-dependent phase information into classical signs that can be evaluated from local measurement outcomes. This leads to Bell tests built from CHSH blocks using two binary measurements per party and no entangling measurements. At maximal violation, the tests self-test the normalized Choi state and the measured observables. Away from the maximum, they give an explicit affine lower bound on the extracted-state squared fidelity that is uniform over all Boolean functions and valid in arbitrary local dimensions. We then combine an identity test and a gate-output test in an independent-source network in which the reference devices use the same physical observables, obtaining a closed-form Choi-fidelity bound for an effective \(n\)-
qubit channel. For CCZ, a joint six-party analysis gives a stronger robustness bound without changing the Bell expression or measurement settings. The construction shows how the algebraic structure of a gate can shift target-dependent information from
quantum measurement design to classical processing of local outcomes.
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All authors Yunguang Han, Xingyuan Bu, Aleksandra Gočanin, Jiabing Yuan
High Energy Physics (Phenomenology)
Radiative Corrections to the Direct Detection of Inelastic Scattering of Higgsino-like Neutralino Dark Matter
Arindam Chatterjee, Debottam Das, Syed Adil Pasha et al. (+2 more)
The direct detection (DD) of Higgsino-like dark matter (DM) through inelastic scattering processes may provide a promising avenue, along with the elastic scattering, when the mass splitting between the neutral Higgsino pairs is extremely tiny. The mass splitting can be reduced further by adopting the on-shell renormalization for the neutral and charged Higgsinos in the MSSM. Moreover, all the one-loop electroweak (EW) corrections to the three-point vertices for the neutralino(s)-
Higgs interactions have been considered, while both elastic and inelastic DM-nucleon scattering cross-sections have been calculated primarily through
Higgs exchange. Subsequently, the expected number of scattering events in the latest LUX-ZEPLIN (LZ) DD experiment are also computed. Our results highlight a few scenarios in which the inelastic component may exceed the corresponding elastic component, leading to enhanced direct detection scattering rates.
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All authors Arindam Chatterjee, Debottam Das, Syed Adil Pasha, Alexander Pukhov, Rahul Puri
Optics
Stable vortex soliton arrays in disclination-fractal systems
Shuang Shen, Milivoj R. Belić, Ce Shang et al. (+2 more)
Vortex light fields carry orbital angular momentum and have attracted significant
attention because of their wide applications in light field manipulations, optical communications, and
quantum information processing. In nonlinear media, the balance between diffraction and self-action enables the formation of
vortex solitons. However, achieving the stability of
vortex solitons remains challenging due to radial and azimuthal modulation instabilities. Here, we report stable
vortex solitons and
vortex-
soliton arrays in disclination-fractal configurations with different rotational
symmetries, constructed by applying disclination operations to fractal
lattice structures. The stable
vortex-
soliton arrays—composed of several
vortex solitons—can exist along domain walls, resulting from the disclination operation applied to the topologically trivial phase. Their stability is verified through both linear stability analysis and direct simulations of perturbed propagation. For comparison,
vortex-
soliton arrays in conventional disclination configurations are found to be completely unstable, demonstrating the significance of the fractal configuration in stabilizing these nonlinear states. These findings reveal a new nonlinear excitation mechanism arising from the interplay between fractal geometry and disclination defects, thereby providing theoretical underpinnings for both the improved understanding of multi-field excitation phenomena in complex
geometric systems and opening new avenues for the design of photonic devices based on fractal disclination structures.
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All authors Shuang Shen, Milivoj R. Belić, Ce Shang, Yongdong Li, Yiqi Zhang
Solar and Stellar Astrophysics
Validity of the CRD limit for modeling scattering polarization in the photospheric Sr I 4607 Å line
Simone Riva, Gioele Janett, Franziska Zeuner et al. (+3 more)
Context. Scattering polarization in the Sr I 4607 Å line is a key diagnostic for small-scale, unresolved
magnetic fields in the quiet
solar photosphere, inaccessible to Zeeman-based techniques. The complete frequency redistribution (CRD) limit is commonly used to model this line, but its validity and impact on
magnetic sensitivity have not been systematically investigated. This is timely given new facilities observing this line with unprecedented accuracy, and future synoptic programs targeting long-term quiet-Sun magnetism. Aims. We assess the CRD limit against the general partial frequency redistribution (PRD) description of scattering for the Sr I 4607 Å polarization, focusing on its
magnetic sensitivity via the Hanle effect. Methods. We solved the non-LTE radiative transfer problem for polarized radiation in a semi-empirical 1D plane-parallel static atmosphere, with CRD and PRD scattering, across
magnetic field configurations relevant for Hanle diagnostics. Results. For small-scale unresolved fields, where the field acts only via Hanle depolarization of Q/I, CRD and PRD emergent profiles and Hanle sensitivity are essentially identical. For deterministic fields, CRD remains accurate when polarization signals exceed about 0.3%; for weaker signals, PRD effects can appreciably affect the emergent profiles. Conclusions. CRD is adequate for modeling Sr I 4607 Å scattering polarization in the vast majority of observationally relevant cases; PRD effects matter only for weak polarization signals.
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All authors Simone Riva, Gioele Janett, Franziska Zeuner, Luca Belluzzi, Fabio Riva, Pietro Benedusi
General Relativity and Quantum Cosmology
Clock-noise propagation and calibration for phase-locking configurations in space-based gravitational-wave detectors
Pan-Pan Wang and Cheng-Gang Shao
In space-based gravitational-wave detectors,
laser phase locking transfers the phase of weak received light to a local
laser and maintains the interspacecraft heterodyne frequencies within the phasemeter bandwidth. Fluctuations of the onboard ultrastable oscillators introduce clock noise into these heterodyne phase measurements, requiring additional calibration in time-delay interferometry (TDI). Existing formulations based on six independently formed one-way measurements do not explicitly describe the common-reference clock structure of a master–slave phase-locking configuration. In this work, we formulate clock-noise propagation and calibration directly for this configuration. Starting from carrier and sideband readouts, we derive the clock-noise couplings and construct an ordered sideband-calibration rule. The rule retains noncommuting delays and applies to two-branch TDI combinations satisfying propagation and clock-coefficient closure. For mutually independent onboard clocks with identical fractional-frequency noise spectra, we compare matched realizations with and without phase locking. In the adopted frozen equal-arm model, 45 second-generation combinations with up to 16 links considered here have smaller clock-noise residuals in the phase-locking realization throughout 0.1–10~mHz, before final clock calibration. Numerical simulations of two representative 16-link combinations reproduce the analytical spectra and verify the predicted reduction and calibration. These results show that the phase-locking realizations reduce the clock-noise contribution before final calibration, while the cancellation of master-
laser phase noise still relies on TDI.
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High Energy Physics (Theory) · Cross-listed from math.AT
The hyperbolic class and vanishing laws in a TMF-valued four-manifold invariant
Yuqi Li and Hao-Yu Sun
Under explicit hypotheses on the spectral Looijenga construction, we compute the
hyperbolic-plane value of the zero-section invariant of Gukov, Krushkal, Meier, and Pei in periodic topological modular forms. The value is the
Hopf element eta, and adjoining a
hyperbolic plane acts by multiplication by this element. Earlier work obtains the
hyperbolic value under an additional cobordism-duality assumption; here we derive it directly from the Looijenga restriction maps without that assumption. Together with annihilation and vanishing results for definite
lattices, this gives a complete value formula on smooth closed simply connected
spin four-
manifolds. In particular, nonzero signature forces the invariant to vanish, so both orientations of a K3 surface have value zero.
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General Relativity and Quantum Cosmology
Thermodynamics of Kerr-Newman-Bertotti-Robinson black holes
Zelin Zhang, Zhenyu Zhang and Bin Chen
In this work, we extend the thermodynamic analyses of the neutral and specially charged Kerr-Bertotti-Robinson black holes to the general Kerr-Newman-Bertotti-Robinson family, in which the electric and external-field parameters are independent. Using covariant surface charges and canonical integrability methods, we determine the total angular momentum and the canonical mass. The angular momentum follows analytically from the combined gravitational and electromagnetic surface charges. However, the infinitesimal charge associated with coordinate time translations is not integrable in solution space, so the mass must be associated with a more general
symmetry generator. Imposing the canonical integrability conditions on this generator, together with the Kerr-Newman mass as the zero-field boundary condition, selects the Christodoulou-Ruffini mass and determines the associated thermodynamic potentials. The first law and Smarr formula take the same form as the ones in usual Kerr-Newman case, and the two previously studied Kerr-Bertotti-Robinson cases are recovered as special limits.
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Chemical Physics
Comprehensive Study of L-Menthol and Octanoic Acid as a Hydrophobic Eutectic Solvent
Bernarda Lovrinčević, Martina Požar, Romana Cerc Korošec et al. (+4 more)
Hydrophobic eutectic solvents (HES) based on natural compounds represent promising green alternatives to conventional solvents. In this work, we investigate the physicochemical, structural, and dynamical properties of an ES formed by L-menthol and octanoic acid using a combined experimental and molecular dynamics simulation approach. Five compositions with molar ratios from 1:3 to 3:1 were studied with molecular dynamics simulation in the temperature range 15 degrees C to 35 degrees C. Experimental measurements of density and viscosity in the temperature range from 5 degrees C to 35 degrees C were complemented with results obtained from MD simulations employing the OPLS force field. Structural analyses based on radial distribution functions and Kirkwood-Buff integrals reveal that the dominant interactions in the mixture are hydrogen bonds between L-menthol and octanoic acid molecules. Dynamic properties, including self-
diffusion coefficients and hydrogen-bond lifetimes, indicate that intermolecular hydrogen bonds between the two components are stronger and longer-lived than bonds between identical species. These findings provide molecular-level insight into the structure and transport properties of menthol-based ESs relevant for green solvent applications.
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All authors Bernarda Lovrinčević, Martina Požar, Romana Cerc Korošec, Klara Švegelj, Peter Ogrin, Marija Bešter-Rogač, Tomaž Urbič