Physics and Society
Feedback dynamics in matching networks drive behavioral differentiation despite overlapping objectives
Alexandros Gelastopoulos
Many bipartite social networks exhibit pronounced asymmetries in selectivity and matching opportunities: members of one side can afford to be highly selective, while members of the opposite side are forced to accept less desirable matches. While it is natural to try to explain this asymmetry in terms of the intrinsic characteristics of the two sides or other exogenous factors, here we show that such asymmetries can also emerge endogenously through a feedback process generated by the matching process itself: as one side becomes more selective, the other side is pushed to be less selective due to reduced matching opportunities, and vice versa. We develop a model in which individuals repeatedly form one-to-one matches across two groups and adapt their selectivity to achieve a target matching rate. Using both analytic and numerical methods, we show that when encounters are sufficiently frequent, the unique
equilibrium is for one group to be highly selective and the other non-selective. This qualitative outcome holds even for heterogeneous groups with overlapping, almost indistinguishable distributions of target matching rates. The model makes several testable predictions, and it provides a mechanism for behavioral differentiation in repeated matching environments, with applications ranging from online dating to hiring and housing
markets.
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Quantum Physics
Correlation is magic in electronic structure Hamiltonians
Basie Seibert, Sam Alterman, Qingfeng Wang et al. (+3 more)
The gate and
qubit requirements of
quantum computations of electronic structure have been extensively studied. However, the
quantum resources present in electronic ground states, as measured by
entanglement and magic, remain less well understood. We study the relationship between correlation in electronic structure
Hamiltonians and magic as measured by the 2-stabilizer Renyi
entropy (2-SRE). Perturbative calculations show that the 2-SRE of a given state is proportional to its overlap with a reference stabilizer state. In the context of
quantum chemistry, this links the magic of electronic structure ground states to their Hartree-Fock weight, an established measure of electronic correlation. We then show that the 2-SRE of post-Hartree-Fock ground states is proportional to the correlation energy they recover. We explore this connection through the contextual subspace (CS) method. We present a theoretical framework showing that the CS method can be used to monotonically vary the magic of approximate CS ground states, and we prove that the correlation energy recovered by the CS ground states is proportional to the magic present in the approximate ground state. We present simulation results using 190 molecular species under Jordan-Wigner encoding at a range of bond lengths. The linear relationships between magic and correlation are robust across the
Hamiltonians in our
dataset, but break down at bond lengths beyond the Coulson-Fischer point, where Hartree-Fock fails to capture key physical features of the true ground state wavefunction. By establishing linear relationships for both correlation energy and Hartree-Fock reference weight with the 2-SRE, we conclude that for weakly- and moderately-correlated electronic structure
Hamiltonians, the correlation is directly represented by 2-SRE, and thus by the magic.
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All authors Basie Seibert, Sam Alterman, Qingfeng Wang, Feng Qian, Akimasa Miyake, Peter J. Love
High Energy Astrophysical Phenomena
Evidence for Millihertz Oscillations in the bright atoll source GX 3+1
Malu Sudha, Renee M. Ludlam, Diego Altamirano et al. (+2 more)
We report evidence for millihertz (mHz) QPOs in the bright atoll
neutron star low-mass X-ray binary (NS LMXB) source GX 3+1 using NICER in the 0.5–10 keV energy band. Across 7 observational
datasets obtained over 6 days, we made 8 candidate mHz QPO detections with local significance above 95%, one of which remains above 95% global significance after the trial correction. These mHz QPOs were detected in the 7–15 mHz frequency range and had fractional rms amplitudes ranging from 0.51–1.41%. Our studies indicate no association between the hardness intensity diagram location of the candidate QPOs and their rms amplitudes. There appears to be a monotonous increase in rms with energy, except in some observations where there is a pivot around 3–4 keV or at ~ 5 keV. Previous studies of mHz QPOs in other sources in literature indicate a pivot around 3 keV in the rms-energy relation, but in our study some tentative detections suggest a pivot at around ~ 5 keV, though the large uncertainties in most cases prevent a robust statistical claim. Although properties such as the frequency range of detection and fractional rms amplitudes of the mHz QPOs in our study are well in agreement with that in literature for other NS LMXBs, the luminosity at which these candidate QPOs occur are higher than that of other sources. The rms-energy relation of the candidate mHz QPOs and the luminosity at which they occur challenges some of the existing considerations of mHz QPO origin.
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All authors Malu Sudha, Renee M. Ludlam, Diego Altamirano, Edward M. Cackett, Mason Ng
Plasma Physics
Plasma double layer development during high power EUV exposure
Manis Chaudhuri, Pavel Krainov, Dmitry Astakhov et al. (+2 more)
The development of electrostatic
plasma double layer (DL) at the boundary of Extreme Ultra Violet (EUV) exposed and un-exposed region in the bulk volume has been confirmed by 3DPIC (Particle-In-
Cell) simulations in the context of fast transient high power EUV exposures. It is found that the DL exists only for short time scale during EUV-ON time period (~ 70ns) and disappears soon after EUV is OFF. Such DL fingerprint appears above a certain critical value of EUV beam energy (~ 0.1mJ) and it transforms from weak-to-strong DL with further increase of EUV power.
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All authors Manis Chaudhuri, Pavel Krainov, Dmitry Astakhov, Andrei M. Yakunin, Mark van de Kerkhof
Instrumentation and Methods for Astrophysics
Test Management and Coordination During the Vera C. Rubin Observatory Commissioning and Early Operations Using Zephyr Scale
Bruno Quint, Tiago Ribeiro, Erik Dennihy et al. (+3 more)
The commissioning of the NSF-DOE Vera C. Rubin Observatory required coordinating the planning, design, and execution of hundreds of integration and on-sky tests involving different subsystems and geographically distributed teams. To support this task, we adopted a Jira-native test management tool, Zephyr Scale. The initial use of Zephyr Scale focused solely on system verification and validation. Its use was rescoped to coordinate higher-level tests, and it is still in use in early operations. Zephyr Scale allows the creation of Test Cases, which represent individual tests. Each Test Case contains the information needed to execute a test at the summit. This includes a step-by-step script. Every day, Test Cases are grouped into a Test Cycle, which represents the test plan for all tests to be executed that day and that same night. We describe the defined workflow for test creation, review, and deployment, which bridges the gap between ideation and on-sky execution within a Test Cycle. We also outline how we write more complex tests as partially automated JSON files consumed by the Scheduler–the system's real-time, constraint-aware observation optimization engine. This integration enables the Scheduler to ingest high-level observing scripts that communicate with subsystems via an abstraction layer to execute common observatory operations, such as slewing, tracking, and data acquisition. Finally, we summarize the benefits and limitations of using Zephyr Scale, designed initially to coordinate software testing, for large-scale observatory commissioning and early operations.
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All authors Bruno Quint, Tiago Ribeiro, Erik Dennihy, Brian Stalder, David Sanmartim, Keith Bechtol
Instrumentation and Methods for Astrophysics
Modeling of the diffuse background produced by the Vera C. Rubin Observatory M2 baffle scattered light
Alessio Taranto, Gabriele Rodeghiero, Luca Rosignoli et al. (+58 more)
The Vera C. Rubin Observatory, with its unprecedented field of view and fast focal ratio, will survey the entire sky every 3.5 nights. This unique capacity requires dealing with off axis light that can produce stray light artefacts on the images. The secondary mirror (M2) baffle restricts the light that reaches the LSSTCam detector and it contributes to shaping the inner edge of the
telescope optical pupil. This work studies the contribution to the background from the light scattered by the M2 baffle itself. The evanescence of this feature, together with the challenge of isolating it from the sky background, led to the necessity of performing in dome tests using a Collimated Beam Projector (CBP), normally used for calibration purposes. To complete the analysis, in addition to the in dome tests, an on sky observational campaign was conducted. This campaign employed both
stellar targets and the Moon as illumination sources in order to determine the actual energy associated with the feature. The test data have been retro fitted thanks to the combination of ray tracing simulation, CBP and on sky data to infer the intensity and spatial distribution of the background scattered light within the different LSSTCam filters. We quantified the on sky impact of scattered light from the M2 baffle, both for light coming from bright and red
stars and from the Moon. We also developed an approximate relation to transform the in dome measurements into predictions of on sky behavior. This transformation was achieved by comparing the illumination footprint produced by an off axis
star with that generated by the CBP and by mapping the
stellar Spectral Energy Distribution (SED) onto the CBP's set of discrete wavelengths. Finally, we extrapolated the scattered light behavior of the Moon to
stellar sources, in order to build a compplete description of the M2 baffle contribution over the full range of magnitudes.
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All authors Alessio Taranto, Gabriele Rodeghiero, Luca Rosignoli, Aashay Pai, Alex Drlica Wagner, Elana K. Urbach, Fritz Muller, Eli S. Rykoff, Hannah M.M.Pollek, John Andrew, Douglas R. Neill, Parker Fragelius, Tomislav Vucina, Christopher W. Stubbs, Robert H. Lupton, Lee S. Kelvin, Kate Napier, Jacqueline Seron Navarrete, Travis Lange, Andrew P. Rasmussen, Aaron Roodman, Chuck F. Claver, Joshua E. Meyers, Anastasia Alexov, Keith Bechtol, Brian Stalder, R. Lynne Jones, Leanne P. Guy, Tiago Ribeiro, Erik Dennihy, Bruno C. Quint, Aaron E. Watkins, Alysha B. Shugart, Lukas Eisert, Kevin Fanning, Marina S. Pavlovich, Yijung Kang, Hye Yun Park, Paulo Lago, Kris Mortensen, Paulina Venegas Salas, Minhee Hyun, Karla Pena Ramirez, David Sanmartim, Qianjun Hang, Gonzalo Aravena, Kshitija Kelkar, Carlos A. L. Morales Marin, Danica Zilkova, Eric J. Christensen, Yusra Alsayyad, William O'Mullane, Enrico Giro, Rodolfo Canestrari, Sandrine J. Thomas, Kevin A. Reil, Claudio H. Araya Cortes, Roberto Tighe, Holger Drass, Pablo Zorzi, Massimo Brescia
Instrumentation and Methods for Astrophysics
Laser-based metrology systems vs wavefront sensing techniques: a comparative overview between the Large Binocular Telescope and the Vera C. Rubin Observatory for the telescope alignment and collimation tracking
Luca Rosignoli, Gabriele Rodeghiero, Sandrine J. Thomas et al. (+26 more)
This work presents a comparative overview of the collimation and
alignment strategies employed by two leading 8m-class facilities: the Large Binocular
Telescope (LBT) and the Vera C. Rubin Observatory. While both
telescopes share a challenging fast f-number of approximately f/1.2 (considering the LBT in its
Prime Focus configuration), they have adopted reciprocal architectures for the initial optical
alignment strategy and for maintaining collimation during the night. As an initial
alignment strategy, the LBT relies on a Wavefront Sensing technique called Focal Plane Image Analysis. Conversely, the Vera C. Rubin Observatory baseline foresees the usage of a
Laser Tracker system to establish the initial optical states. The strategies for preserving the optical
alignment and maintaining the collimation against gravitational flexure and thermal drift during observations are instead reversed. Besides the use of open-loop corrections based on Look-Up Tables, common on both
telescopes, the LBT utilizes a
laser-based
Telescope Metrology System to monitor the relative position of optics in real-time, applying the corrections between the exposures. In contrast, the Rubin Observatory employs a
Curvature Wavefront Sensing technique, using dedicated detectors at the four corners of the focal plane. Rather than identifying a best strategy, this work aims to synthesize the strengths, limitations, and operational trade-offs of these complementary approaches, from the perspective of the next generation of Extremely Large
Telescopes and their instruments.
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All authors Luca Rosignoli, Gabriele Rodeghiero, Sandrine J. Thomas, Guillem Megias Homar, Heejoo Choi, John Hill, Olga Kuhn, Elena Masciadri, Byeongjoon Jeong, Brandon Mechtley, Christian Veillet, Elana Urbach, Brian Stalder, Jason Chu, Alessio Taranto, J. Bryce Kalmbach, Joshua E. Meyers, Andrew J. Connolly, Rebekah Polen, John Franklin Crenshaw, Krzysztof Suberlak, Tiago Ribeiro, Roberto Tighe, Merlin Fisher-Levine, Mario Rivera, Enrico Giro, Rodolfo Canestrari, Holger Drass, Pablo Zorzi Massimo Brescia
Quantum Physics
Context-Verified, Error-Budget-Aware Decomposition Selection for Toffoli Networks
Karol Bartkiewicz and Patrycja Tulewicz
The cheapest Toffoli (CCX) decompositions (relative-phase and control-reduced Toffolis) save two-
qubit gates, which dominate the error budget of near-term hardware, but they are correct only in context, since a relative phase is observable only when superposed branches interfere. We propose
quantum chip performance tuning (QCPT), a compiler that selects the cheapest decomposition for each Toffoli (stage 1) and admits it only if a per-instance check shows that it equals the exact gate, up to one phase, on every state that can enter it; a whole-
circuit certificate gates the output. The output acts as the exact
circuit on every valid input, superposed ones included, up to a reported global phase, which per-state checks do not guarantee. Substituting relative-phase Toffolis wherever they fit changes the
unitary of six of twelve
benchmark circuits used as subroutines, whereas stage 1 changes none and removes 31.0% of the two-
qubit gates. A certified resynthesis of classical
circuits of up to ten
qubits raises the saving to 43.1% on the primary suite and to 57.5% on 20 small RevLib
circuits (in-sample). A bound on the compilation error plus the per-gate device error separates what the compiler adds from what a depolarizing two-
qubit model of the device adds. In mirror tests on ibm_aachen, QCPT (best of four candidates, one of them the Qiskit
circuit) returns more often than Qiskit on all nine
circuits; in simulation with the calibration that drives its selection, on 29 of 33
circuits and worse on none by more than 0.01. An iterative
language-model search with our certificate obtains no fewer gates on any of nine
circuits and needs about 45 times longer (one run each). QCPT gives no gain without Toffoli structure. Certified context-dependent selection can thus let near-term devices run larger Toffoli
circuits at a given success probability, with a gain that varies by family.
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Soft Condensed Matter
Nonlinear diffusion and compressive rims in source-driven biopolymer condensates
Avraham Moriel and Howard A. Stone
Many subcellular condensates continuously produce biopolymers. Coupling Flory-Huggins thermodynamics to two-fluid viscoelasticity, we probe the
diffusion of such source-driven polymeric droplets, and identify a universal structural compressive rim at their
diffusion front. Integrating analytical scaling laws, numerical simulations, and experimental data, we show that this framework captures key structural and dynamic characteristics of the nucleolus, demonstrating the role of
polymer diffusion in non-
equilibrium biological transport.
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Mathematical Physics
Kinetic derivation of thermal viscous models for nematic liquid crystal dynamics
P. E. Farrell, J. Málek, O. Souček et al. (+1 more)
We develop a macroscopic thermodynamic theory of nematic
liquid crystals starting from a kinetic theory of ordered fluids with a collision operator of Bhatnagar-Gross-Krook (BGK) type. The kinetic description incorporates mean-field
alignment interactions through a Vlasov potential and relies on a separation of time scales, with orientational relaxation occurring on a faster time scale than translational momentum relaxation. At the continuum level, we establish the balance equations for mass, linear and angular momentum, energy, and
entropy. Using the zeroth and first order Chapman-Enskog expansions, we derive a constitutive equation for the Helmholtz free energy and identify the associated structural form of the
entropy production rate. We then exploit additional information from the kinetic description to determine a constitutive relation for the
entropy production rate itself. Finally, by applying the constrained maximisation procedure of Rajagopal and Srinivasa, we obtain constitutive equations for the Cauchy stress and couple-stress tensors, as well as for the energy and
entropy fluxes. In this way we generalise the recent inviscid kinetic theory of Farrell, Russo, and Zerbinati to account for viscous, thermal, and
spin-diffusive effects, using the simplest BGK-type approximation of the collision operator. Both compressible and incompressible variants of the theory are presented.
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All authors P. E. Farrell, J. Málek, O. Souček, U. Zerbinati
Physics and Society
Information-Epidemic Dynamics in Cyber-Physical Systems: A Hypergraph Framework with Interpersonal Relationships
Shanchao Peng, Minyu Feng, Liang-Jian Deng et al. (+2 more)
Understanding how information propagation affects epidemic dynamics has become an emerging topic of interest. However, the influence of interpersonal relationship heterogeneity on information acquisition and disease transmission has been largely overlooked. In this work, we introduce a hypergraph structure for Cyber-Physical Systems (CPSs) with two distinct layers. The upper layer, referred to as the cyber layer, consists of a mixed hypergraph, capturing both pairwise propagation and higher-order
diffusion of epidemic-related information. The lower layer, referred to as the physical layer, employs a Susceptible-Infected-Susceptible (SIS) process to capture epidemic spreading. This work introduces an adaptive perception-protection mechanism based on Jaccard similarity, which accounts for interpersonal heterogeneity. In this mechanism, individuals receive information based on their relationships with neighbors and take protective measures accordingly. We analyze the impact of interpersonal relationships and the adoption of neighborhood-based self-protection strategies on epidemic dynamics. Furthermore, we conduct a theoretical analysis based on the Microscopic Markov Chain Approach (MMCA), analytically derive the outbreak threshold, and confirm the results with extensive Monte Carlo (MC) simulations. The results show that stronger interpersonal relationships can promote information propagation, significantly increase the threshold for epidemic outbreaks, and effectively suppress the scale of the epidemic. The study provides theoretical support for designing epidemic control strategies considering interpersonal heterogeneity and improves the understanding of epidemic spreading on hypergraphs.
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All authors Shanchao Peng, Minyu Feng, Liang-Jian Deng, Matjaž Perc, Jürgen Kurths
Instrumentation and Methods for Astrophysics
Setting requirements on out-of-band rejection for next-generation CMB experiments. Application to the LiteBIRD instrument
L. Mousset, L. Montier, J. Aumont et al. (+15 more)
Next-generation
cosmic microwave background experiments have very stringent constraints to achieve the required sensitivity to target polarization $B$ modes. In this work, we intend to set requirements on the out-of-band rejection level, with out-of-band referring to frequencies outside the
telescope band-pass. The method developed is applied to the LiteBIRD Medium and High Frequency
Telescopes. In order to determine the impact of out-of-band power, we model the instrument's optical response and the spectral emissions of the sky and of the instrument itself. This allows us to propagate optical power inside the
telescope. Using this tool, we address both the impact of out-of-band power on the detection chain and on the thermal heat load, together with the impact on the process of separation between astrophysical components. The role of additional static power as well as dynamic power variations is studied. The requirement derived consist in attenuation factors (in dB) in frequency subdomains. They will be used to design the
telescopes filters.
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All authors L. Mousset, L. Montier, J. Aumont, F. Columbro, P. de Bernardis, J. Errard, C. Franceschet, S. Giardiello, T. Ghigna, H. Hubmayr, G. Jaehnig, S. Masi, F. Piacentini, G. Pisano, A. Rizzieri, G. Savini, C. Tucker, LiteBIRD Collaboration
Mesoscale and Nanoscale Physics
Energy-time entanglement from a monolithically integrated quantum dot on silicon
Marcel Hohn, Imad Limame, Peter Ludewig et al. (+4 more)
Scalable
quantum photonic technologies require deterministic sources of entangled
photons that are compatible with established
semiconductor manufacturing platforms. While self-assembled III–V
semiconductor quantum dots are among the most promising sources of on-demand
entanglement generation, their integration with silicon-based architectures remains a central challenge. Here, we demonstrate energy–time
entanglement from a single InGaAs/GaAs
quantum dot monolithically grown on a silicon substrate. Under coherent two-
photon excitation, we achieve coherent control of the biexciton–
exciton cascade, evidenced by Rabi oscillations and dressed-state formation. Using a four-channel Franson interferometer, we observe phase-dependent two-
photon interference with visibilities up to $(64.0 \pm 7.0)\%$ for an 80 ps integration window (and $(49.4 \pm 1.9)\%$ for a 1600 ps window), approaching the threshold for Bell inequality violation at short time scales. These results establish monolithically integrated III–V-on-silicon
quantum dots as promising sources of energy–time entangled
photons for scalable
quantum photonic technologies.
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All authors Marcel Hohn, Imad Limame, Peter Ludewig, Chirag C. Palekar, Aris Koulas-Simos, Kerstin Volz, Stephan Reitzenstein
Astrophysics of Galaxies
Uncovering neutral Hydrogen clouds in Radio Galaxies in the SKA era
Mamta Pandey-Pommier
AGN feedback driven by
radio jets plays a key role in regulating the cold ISM of
galaxies. Neutral hydrogen traced through the H1 21-cm line provides a powerful probe of the kinematics, distribution, and physical conditions of cold gas in the central regions of AGN. Previous observations have detected H1 column densities down to $\sim10^{20}$ cm$^{-2}$, but typically at arcsecond-scale resolution, inhibiting the characterization of small-scale H1 gas clouds and their connection to molecular gas reservoirs and sites of jet-ISM interaction. High-resolution H1 imaging is therefore required to determine whether the atomic gas is associated with circumnuclear structures, jet-driven
outflows, compressed gas layers, or fragmented cold clouds embedded within a disturbed multiphase ISM. In this chapter, we focus on molecular gas-rich
radio AGN hosting large-scale jets and exhibiting strong interactions between the
radio plasma and the surrounding ISM, where atomic, molecular, and ionized gas coexist. These systems provide ideal laboratories for investigating the spatial distribution and kinematics of H1, constraining the impact of
radio jets on the cold gas, and determining whether the gas is associated with inflowing, outflowing, or otherwise disturbed components. SKA-VLBI will deliver milliarcsecond-scale imaging and $\mu$Jy-level sensitivity, resolving H1 gas clouds on parsec scales across extended
radio structures. This capability will enable detailed constraints on the location, morphology, and kinematics of atomic gas from the
nuclear regions to kiloparsec-scale jet-ISM interaction sites. Combined with molecular gas observations at other wavelengths, these measurements will provide a comprehensive view of the jet-ISM interactions, the impact of AGN-driven feedback, and the role of cold gas in
galaxy evolution.
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Quantum Physics
Improving Perturbation Theory with the Sum-of-squares II: Large Density-Density Terms
Matthew B. Hastings
In Ref. 1, a method was given for self-consistently generating sum-of-squares decompositions of quartic fermionic
Hamiltonians. Perturbation theory was used to generate a useful choice of cubic operators in this sum-of-squares. On a range of model problems, this method, which is only a fragment of degree-six sum-of-squares, was able to outperform the full degree-four sum-of-squares in both speed and accuracy. Unfortunately for applications, many problems in chemistry have strong density-density interaction terms, as well as moderately strong density-dependent hopping and
spin-
spin interaction terms, limiting the power of the perturbative choice of the cubic operators. Here we propose a method for generating these decompositions in the presence of these strong interaction terms, hopefully extending the range of applicability of this method.
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Optics
Plasmon-Enabled High-Precision Single Molecule Localization Microscopy over an Extended Field of View
Muzzamal I. Shaukat, Carlos E. Rodriguez, M. Suhail Zubairy et al. (+1 more)
We propose PIFLUX, a single-molecule localization scheme combining deep-subwavelength plasmonic illumination with widefield detection. Interference between counter-propagating gap plasmons and a normally incident optical field generates an illumination pattern whose position can be tuned through the plasmon phase while preserving its spatial period. A Cramér-Rao analysis shows PIFLUX reaches few-nanometer precision matching MINFLUX while doubling that of SIMFLUX over a micrometer field of view, and a maximum-likelihood
estimator confirms this on a synthetic
nuclear pore complex.
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All authors Muzzamal I. Shaukat, Carlos E. Rodriguez, M. Suhail Zubairy, Oumeng Zhang
High Energy Astrophysical Phenomena
The location of the upper edge of the pair-instability supernovae black hole mass gap
Jeremy Sakstein and Djuna Croon
Gravitational wave observations are beginning to probe the upper edge of the pair-instability
supernova (PISN) black hole mass gap, a key prediction of
stellar evolution. In this work, we quantify the sensitivity of this boundary to uncertainties in
stellar evolution using a suite of simulations that vary inputs including
nuclear reaction rates, mixing processes, and
stellar winds. We find that the $^{12}{\rm C}(\alpha,\gamma)^{16}{\rm O}$ reaction rate is the dominant source of uncertainty, shifting the upper edge by $\Delta M\sim30\,{\rm M}_\odot$, with the triple-$\alpha$ rate producing a comparable shift of $\sim25\,{\rm M}_\odot$. Notably, $^{16}{\rm O}+^{16}{\rm O}$ reactions shift the upper edge by $\sim15\,{\rm M}_\odot$ while leaving the lower edge unchanged, implying they can widen or narrow the mass gap. Other processes affect the location at the $\lesssim10\,{\rm M}_\odot$ level. In contrast to the lower edge, we find that the upper edge is robust to variations in spatial and temporal resolution, indicating that it is reliably resolved in current simulations. Our results demonstrate that the upper edge carries substantial theoretical uncertainty and, while comparatively less affected by astrophysical contamination than the lower edge, provides a direct probe of the
nuclear processes governing pair instability. We discuss the implications for interpreting high-mass black hole detections in gravitational wave data.
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High Energy Physics (Phenomenology)
Emergent Local Phase-Space Scaling in Small-x Gluon Evolution
Lei Wang
Geometric scaling is a central output of nonlinear small-$x$
evolution, but it is less clear whether the same dynamics fixes a probability distribution in transverse phase space. Using fixed-coupling impact-parameter BK
evolution in the $SO(3)$-symmetric construction, we build a normalized
gluon Husimi phase-space distribution and resolve it with a local coarse graining whose ultraviolet boundary follows $Q_s(Y,b)$. The main result is a distribution-level one: after this $Q_s$-adaptive resolution, the conditional momentum distributions collapse as functions of $k/Q_s(Y,b)$. The conditional
entropy then grows with unit slope relative to $\langle\ln Q_s^2\rangle$, as the integrated consequence of that collapse and the two-dimensional momentum measure. Fixed laboratory cutoffs do not show this law, while dense-rapidity, cutoff-window, box-size, regulator-shape, and Husimi-resolution scans keep the $Q_s$-adaptive result stable in the controlled window. Within this fixed-coupling $SO(3)$-BK setting, the result identifies a local phase-space scaling structure of the
gluon Husimi distribution rather than a universal law for unregulated global
entropy.
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Quantum Physics
Distributed Property Testing with (Quantum) Carrier Pigeons: Tight Bounds on State Certification
Kenny Chen
Recently, Doosti et al. introduced the problem of distributed
quantum state verification, where $m$ distributed nodes are given a copy of an unknown state $\rho$, and can send limited one way communication to a central node, who has a complete description of a known state $\sigma$. They ask how many distributed nodes $m$ are required, before the central node can succeed at distinguishing whether $\rho=\sigma$ or $\|\rho-\sigma\|_1\geq\varepsilon$ with high probability. In the setting where only
quantum communication is allowed, Doosti et al. exhibit conditional lower bounds in both the public and private-coin settings, and a matching upper bound in the public-coin setting. We extend these results, and show unconditional lower bounds for when both classical and
quantum communication are permitted. We show the public-coin lower bound is tight by giving an
algorithm with a matching upper bound. We also show an almost tight upper bound in the private-coin setting when only
quantum communication is permitted.
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Quantum Physics
Signatures of the circular Unruh effect in electric and magnetic dipole transitions of multilevel atoms
Gregor Janson, Fabio Di Pumpo, Lorenz Thoma et al. (+1 more)
The circular Unruh effect is the excitation of a detector moving along a planar circular trajectory within an electromagnetic
vacuum. We demonstrate that the
magnetic dipole transitions in an atom, acting as the detector, dominate the electric dipole transitions. Our analysis of both free-space and cavity schemes shows that the sensitivity to the circular Unruh effect can be maximized by balancing the minimization of mode volume against the resulting decrease in mode density. Moreover, we propose a novel measurement scheme that uses the atom's multilevel structure to suppress the spontaneous emission rate, thereby enabling the experimental detection of the circular Unruh effect.
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All authors Gregor Janson, Fabio Di Pumpo, Lorenz Thoma, Maxim A. Efremov
Earth and Planetary Astrophysics
Search for L4 Earth Trojan asteroids with the 2.5-meter Wide Field Survey Telescope
Junqiang Lu, Lulu Fan, Shaohan Wang et al. (+16 more)
Earth Trojan asteroids (ETAs) are a mysterious population, and dynamically stable ETAs, if
primordial, could be "living fossils" of the early
solar system. To date, there are only two known ETAs, but both are temporary ETAs. The aim of our survey is to discover new temporary or stable ETAs; in the absence of detections, we derive upper limits on the population of stable ETAs. We conducted the largest wide-area survey of the Earth's L4 Lagrange point region so far using the Wide Field Survey
Telescope, covering about 236.74 deg^2, corresponding to 33.24% of the probability coverage for sky regions where dynamically stable L4 ETAs are likely to reside. No new ETAs were detected in our survey. We place a cumulative upper limit of N(H < 19.1) < 19 on the stable population of objects larger than ~520 m (for an assumed albedo of 0.15). This represents the most stringent constraint on the ETA population to date.
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All authors Junqiang Lu, Lulu Fan, Shaohan Wang, Minxuan Cai, Bingxue Fu, Xu Kong, Haibin Zhao, Bin Li, Qingfeng Zhu, Zhen Wan, Feng Li, Ming Liang, Binyang Liu, Zheng Lou, Jinlong Tang, Hairen Wang, Jian Wang, Yongquan Xue, Hongfei Zhang
Chemical Physics
Visualizing the Hidden Architecture of Molecular Films with Phase-Resolved Rotational SFG Microscopy
Ben John, Tuhin Khan, Nasim Mirzajani et al. (+3 more)
The highly variable physico-chemical properties of thin molecular films play an essential role in numerous research fields ranging from biophysics to the fabrication of functional devices such as molecular sensors. The properties of molecular films are largely governed by their three-dimensional molecular structure which often exhibits important spatial heterogeneity, either naturally, or introduced deliberately. In order to understand and control these properties microscopic insight into structural parameters such as composition, molecular orientation and conformation, as well as molecular order is required, which, so far, represents a mostly unachieved experimental target. In this contribution we present a powerful experimental approach that can overcome this limitation. Using phase-resolved rotational sum-frequency generation (SFG) microscopy all of these structural parameters can be obtained with sub-monolayer sensitivity and at sub-micron resolution. In measurements of monolayer assemblies of mixed phospholipids, we uncover the molecular packing structure in previously-unattained detail and demonstrate the large potential of the technique for the elucidation of the complex architecture inside molecular films. The structural insight provided by this nonlinear microscopy approach spans all the way from the molecular to the macroscopic scale opening the door to a completely new type of interfacial studies.
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All authors Ben John, Tuhin Khan, Nasim Mirzajani, Martin Wolf, Alexander P. Fellows, Martin Thämer
High Energy Physics (Phenomenology)
Finite-Density Dynamics of Chemically Equilibrating QGP in Conformal Gubser Flow and Hard Thermal Photon Production
Lakshmi J. Naik and V. Sreekanth
We study the chemical equilibration of a hot and dense
quark-
gluon plasma (QGP) at finite
baryon density produced in relativistic heavy-ion collisions within conformal Gubser flow. Chemical non-
equilibrium is incorporated through fugacity parameters in the parton phase-space distribution functions, whose
evolution is governed by master rate equations coupled to the hydrodynamic expansion with transverse flow. We analyse the interplay between chemical equilibration and finite-density dynamics, and investigate its impact on hard thermal
photon production. We observe that both finite density and transverse expansion delay chemical equilibration, leading to a chemically undersaturated medium with
quarks lagging behind
gluons. While the overall thermal
photon yield from the expanding system is suppressed in the non-
equilibrium scenario, we find an enhanced early-time contribution to high $p_T$
photon production. By analyzing the instantaneous
photon emission in presence of chemical non-
equilibrium, we demonstrate that the rates exhibit a distinct temporal structure arising from the interplay of rapid cooling and evolving fugacities. These features may provide potential observable signatures of chemical equilibration dynamics in the QGP.
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Solar and Stellar Astrophysics
The CepA disk-outflow system at <=0.2” or <=100au resolution
H. Beuther, C. Gieser, V. Aberham et al. (+21 more)
Context: Although there has been significant progress, the physical properties and potential fragmentation of
accretion disks around high-mass protostars remain poorly constrained. Aims: We characterize at high angular resolution one of the most nearby (~700pc) high-mass
accretion disk candidates CepA HW2. Methods: Using the new long baseline array configuration (~1700m) of the Northern Extended Millimeter Array (NOEMA), we study CepA HW2 with a resolution of <=0.2” or <=100au at 1.3mm in
dust continuum and spectral line emission. Results: The mm continuum emission resolves the central disk candidate into several sub-structures. Conducting a Toomre Q stability analysis based on CH_3CN and continuum data, and a comparison to 3D radiation hydrodynamic simulations shows that the data are consistent with an almost edge-on disk where the observed sub-structures may represent fragments within the disk. The CO and SiO spectral line data confirm a second bipolar
outflow (in addition to the well-known jet) emanating from the central peak position. This indicates that this central peak should host at least a binary if not even a higher order multiple system. The usually assumed dense gas tracer CH_3CN shows also contributions from the
outflows which complicates further kinematic analysis of the disk. Conclusions: The high-resolution
outflow-disk data of CepA reveal a multiply fragmented disk that drives several
outflows. These observations enforce the picture of high-mass
star formation where multiplicity and fragmentation can happen on the smallest spatial scales related to the inner
accretion disks.
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All authors H. Beuther, C. Gieser, V. Aberham, J.M. Winters, R. Neri, A. Ahmadi, R. Kuiper, Th. Henning, H. Linz, T. Möller, V. Elbakyan, L. Moscadelli, D. Semenov, J. Urquhart, P. Klaassen, M. Beltran, Á. Sánchez-Monge, T. Peters, R. Galvan-Madrid, S. Leurini, S. Lumsden, R.E. Pudritz, A. Palau, H. Zinnecker
Instrumentation and Methods for Astrophysics
Focal Plate Prototyping for Modular Focal Planes of Stage-5 Instruments For Ground-Based Telescopes
Maxime Rombach, Jean-David Perriard, Laurent Chevalley et al. (+3 more)
As current Stage-4 multi-object instruments such as SDSS-V, DESI, MOONS or 4MOST are providing astrophysicists data to study the objects of the Universe, effort is arising to build the next generation of Stage-5 multi-object focal planes; aiming for 20'000 fibers-class instruments. The focal plate structure is a central element of the future focal plane assemblies. It maintains the fiber positioners, the Guide, Focus and
Alignment cameras (GFAs) and wave-front sensors together on the focal surface of the
telescope. In addition to being optimized for stiffness and mass, the plate needs to meet tight tolerances in tilt, typically pm 0.05 degres, and focus, typically, pm 30 um, to match the
telescope's curved focal surface. The presented focal plate prototype shows that 5-axes machining is promising to meet the desired tolerances.
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All authors Maxime Rombach, Jean-David Perriard, Laurent Chevalley, Diane Chapuis, Markus Thurneysen, Jean-Paul Kneib
Quantum Physics
Entangled photons from para-positronium decay: Do coincidences from scattered photons imply a Bell state?
Paul Joos and Peter Kling
Electron and positron can form a meta-stable bound state called positronium that decays via pair annihilation. We show how polarization-dependent Compton scattering can be used to verify that the two annihilation
photons in the
spin-zero case (para-positronium) are emitted in a maximally entangled Bell state. Our theoretical approach based on two-
photon density
matrices connects concepts from relativistic
quantum electrodynamics and
quantum information theory.
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High Energy Physics (Theory)
Holographic Krylov Complexity with Lifshitz Scaling and Hyperscaling Violation
Kazem Bitaghsir Fadafan and M. Reza Mohammadi Mozaffar
Following the
holographic proposal that identifies the growth rate of Krylov complexity with the proper radial momentum of an infalling massive probe, we study Krylov complexity in Lifshitz and hyperscaling-violating backgrounds. For pure Lifshitz geometries, we find quadratic complexity growth for all values of the dynamical exponent. For hyperscaling-violating backgrounds, we show that the hyperscaling-violating exponent directly controls the late-time growth exponent, with a special limiting case exhibiting oscillatory behavior with a logarithmic envelope. We also extend our analysis to top-down string constructions, confirming the robustness of the scaling behaviors obtained in the bottom-up approach. Our analysis establishes that the momentum-Krylov correspondence extends naturally to non-relativistic
holographic settings and remains well-defined despite the causal pathologies of Lifshitz spacetimes.
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Quantum Physics
Boosted Optomechanics with a Fluid of Nonlinear Polaritons
Florent Malabat, Martin Colombano, Titouan Lévêque et al. (+4 more)
Merging optomechanics and polaritonics opens stimulating perspectives like the
giant enhancement of optomechanical interaction and the enrichment of optomechanics with effective nonlinear
photons. The experimental implementation of these concepts has however remained elusive. Here we report on the resonant optical control of polaritonic optomechanical resonators constituted of
semiconductor disks
embedding quantum wells. Whispering gallery
photons and
quantum well
excitons strongly couple, leading to the emergence of polaritons that couple to the mechanical vibrations of the disk. We perform resonant optomechanical frequency response experiments on these resonators, modeled introducing a minimal set of constitutive equations, from which we extract the polariton-modified optomechanical coupling $g_0$ and the polariton nonlinearities. We observe a boost of $g_0$ by more than a decade compared to bare
photons, reaching to a record $g_0$ for whispering gallery resonators of $22$ MHz, and analyze experimentally and theoretically its
evolution as function of the polariton's composition. We also measure a clear hierarchy of three polaritonic nonlinearities, again analyzed as function of polariton composition, establishing a bridge between past unconciliated reports in polaritonics. Grounded on experimental and theoretical foundations, resonant polaritonic optomechanics is set ready for an optomechanical exploration of
quantum fluids of polaritons.
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All authors Florent Malabat, Martin Colombano, Titouan Lévêque, Martina Morassi, Aristide Lemaître, Alexandre Le Boité, Ivan Favero
Instrumentation and Methods for Astrophysics
Robust CMB polarisation mapmaking with a rotating half-wave plate
Wuhyun Sohn, Simon Biquard, Josquin Errard et al. (+1 more)
We present a novel mapmaking method for obtaining unbiased estimates of CMB polarisation, tailored to modern CMB experiments with a rotating half-wave plate. These experiments are exposed to strong unpolarised contaminant sources, such as atmospheric emission and ground pickup, which can be several orders of magnitude stronger than the sky signal. Our mapmaker mitigates these systematic effects by marginalising over all signals that vary slowly compared to the timescale of a polarimeter's angle rotation on the sky, while recovering high-fidelity polarisation maps. When the variability timescales of the unpolarised signals exceed a quarter of the half-wave plate rotation period, the method can produce maps with nearly optimal noise levels and minimal contamination. Furthermore, if the half-wave plate rotation period is sufficiently short relative to the beam-scale crossing time, the method efficiently mitigates the sky intensity-to-polarisation leakage. This mapmaker, named the Polarisation-Optimised Map-Making
Estimator (POMME), is implemented within the open-source FURAX package and is ready for application to upcoming ground-based CMB surveys.
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All authors Wuhyun Sohn, Simon Biquard, Josquin Errard, Radek Stompor
Astrophysics of Galaxies
Chemo-dynamical Analysis of Eight UBC Open Clusters
Remziye Canbay, Deniz Cennet Ç{\i}nar, Özcan Çal{\i}şkan et al. (+4 more)
We present a comprehensive chemo-dynamical analysis of eight open clusters selected from the UBC catalog using
Gaia DR3 data. These clusters are located at heliocentric distances of ~2-5 kpc, probing regions of the
Galactic disk beyond the
solar neighborhood. Cluster membership is determined using the UPMASK
algorithm, while structural parameters are derived from radial density profiles through King model fitting combined with MCMC sampling. Their structural parameters reveal diverse internal configurations, from diffuse to moderately concentrated systems. Fundamental astrophysical parameters (extinction, distance,
metallicity, and age) are obtained via
Bayesian isochrone fitting based on PARSEC models. The clusters span a wide age range (~20 Myr to ~5 Gyr) and show a broad
metallicity distribution (-0.34 <= [Fe/H] (dex) <= +0.25). Orbital analysis based on backward integrations shows that all clusters follow nearly circular orbits (e ~ 0.03-0.09) with low vertical distances from the
Galactic plane (Zmax < 0.4 kpc), confirming their membership in the
Galactic thin disk and dynamically cold kinematics. Comparison between inferred traceback orbital radii and present-day guiding radii indicates modest radial displacements, with Delta R < 0.5 kpc for the UBC sample. These offsets are consistent with mild radial redistribution expected for young, dynamically cold open clusters rather than strong radial migration. The results suggest that radial migration should be considered when interpreting the present-day spatial and chemical distribution of these clusters, although the inferred migration amplitudes remain moderate. Our results demonstrate that relatively distant open clusters can be characterized with high precision using
Gaia DR3 data and that mild radial redistribution should be considered when interpreting the present-day distribution of
stellar populations in the
Galactic disk.
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All authors Remziye Canbay, Deniz Cennet Ç{\i}nar, Özcan Çal{\i}şkan, Burçin Tan{\i}k Öztürk, Seval Taşdemir, Ege Erayd{\i}n, Selçuk Bilir