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Physics

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Thursday 11 June

High Energy Physics (Phenomenology)

Conformal calibration and look-elsewhere effect in anomaly detection for new-physics searches

Jack Y. Araz and Michael Spannowsky

Machine-learned anomaly detection is reshaping searches for new physics, but it has outrun the statistics used to interpret it. A raw anomaly score has no calibrated meaning, a model that scans many regions inflates the look-elsewhere effect, and the asymptotic significances the field relies on are blind to the background mismodelling that anomaly detectors are especially prone to. We propose a calibration layer, built on conformal prediction, that turns any anomaly score into a defensible significance with distribution-free, finite-sample guarantees. Conformal prediction converts scores into valid local p-values, weighted and Mondrian variants repair the sideband-to-signal-region exchangeability failures that resonant searches suffer, and a Gross-Vitells step carries the result through to a look-elsewhere-aware global significance. The layer does two things at once. It exposes miscalibration that the standard pipeline cannot see, and it corrects it without retraining the detector. On public LHC Olympics data, a classifier develops a substructure-mass correlation that makes sideband-calibrated background p-values anti-conservative. Taken at face value, this manufactures a $\sim 46\sigma$ excess from background sculpting alone, which the label-free weighted correction removes, restoring an honest null. When run as a blind wide-mass bump hunt, the standard asymptotic and unweighted procedures fabricate $\gtrsim10\sigma$ excesses and $\approx5\sigma$ excesses even in signal-free windows, while the conformal layer raises no false alarms and its global false-positive rate is verified on background-only pseudoexperiments. The result is an auditable, detector-agnostic path from an uncalibrated score to a trials-factor-aware significance, ready to be folded into experimental anomaly searches.
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Quantum Physics

Computational regimes in matrix-product-state-based quantum trajectory simulations

Aaron Sander, Simon Cichy, Martin Eigel et al. (+4 more)

Efficient simulation of open quantum systems is central to modeling noisy quantum hardware and many-body dynamics. In trajectory-based tensor network methods, cost is often associated with trajectory-level quantities such as entanglement growth or bond dimension. However, the total cost of a fixed-accuracy simulation also depends on statistical sampling, and the interplay between per-trajectory complexity and sampling effort remains poorly understood. Here we introduce a cost-resolved framework for matrix product state (MPS)-based quantum trajectory simulations that decomposes total cost into memory per trajectory, runtime per trajectory, and sampling effort. We show that physically equivalent stochastic unravelings of the same Lindblad dynamics do not necessarily reduce total cost, but instead redistribute cost between trajectory complexity and statistical convergence. This trade-off is quantified by two dimensionless inflation factors: a bond dimension inflation $\alpha$ and a sampling inflation $\kappa$, which together determine the preferred unraveling under hardware-dependent memory and parallelism constraints. We provide a practical protocol for extracting $(\alpha,\kappa)$ from modest pilot simulations and demonstrate it using benchmarks across multiple noise channels. The resulting decision maps show that the computationally favorable unraveling can change with noise strength, time-step resolution, system size, and available parallelism. These results establish unraveling choice as a hardware-aware simulation design problem rather than an intrinsic optimization of trajectory entanglement alone.
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All authors Aaron Sander, Simon Cichy, Martin Eigel, Jens Eisert, Maximilian Fröhlich, Tom Peham, Robert Wille

High Energy Physics (Theory)

Resurgence of the Thermal Transition between Bounce and Sphaleron

Shaun D. Hampton, Kyungsun Lee and Sungjay Lee

We study the thermal transition between the bounce and the sphaleron in quantum mechanics with a metastable vacuum from the viewpoint of Borel resurgence. For two models representing a second-order and a first-order transition, we compute the perturbative expansion of the thermal free energy to high orders and extract the leading Borel singularity data $(A,b,S)$ as functions of temperature. The Borel singularity location $A$ reproduces the on-shell action of the dominant saddle on both sides of the transition, joining smoothly in the second-order case and developing a kink in the first-order case. The characteristic exponent $b$ jumps between $0$ and $1/2$ across the transition, counting the zero modes of the corresponding saddle. The Stokes constant $S$ matches the one-loop determinant around the saddle. The perturbative expansion around the false vacuum thus determines the transition temperature, the order of the transition, and the decay rate including the one-loop prefactor without relying on semiclassical inputs.
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Astrophysics of Galaxies

Turbulence in the multi-phase circumgalactic medium: bridging TNG50 and idealized kpc-scale simulations

Jonas Biba and Dylan Nelson

The circumgalactic medium (CGM) is the extended multi-phase gaseous halo surrounding a galaxy. To study how its dynamics are shaped by the interplay of radiative cooling and turbulence, we first turn to the TNG50 cosmological magnetohydrodynamical simulation. We analyze the turbulent properties of the CGM of Milky Way-like galaxies at z=0, using a multi-scale filtering technique. We find that the CGM hosts predominantly subsonic flows with Mach number ~ 0.1 - 0.7 that are roughly balanced between compressive and solenoidal components with b = M_comp / M_tot ~ 0.3 - 0.6. We then use these physically motivated properties of turbulent CGM media to set the initial conditions and driving parameters for idealized, turbulent box simulations. These represent ~ 1 kpc^3 volumes of the CGM, but reach resolutions higher than available in cosmological volumes such as TNG50. To do so, we implement a turbulent driving algorithm into the AREPO code based on random but smoothly time-fluctuating acceleration fields, and then run a suite of turbulent boxes across the parameter space, including a model for metal-line radiative cooling. Using these simulations, we study how turbulence seeds density fluctuations that trigger thermal instability and promotes mixing between hot and cold phases, depending on the relative timescales of cooling and mixing. The abundance and evolution of cold ~10^4 K gas depends strongly on the strength of turbulence and the efficiency of cooling.
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Solar and Stellar Astrophysics

Dynamo Simulations Confirm Predominantly Toroidal Fields in Near-Core Region of an Intermediate-Mass Star

R.P. Ratnasingam and T.M. Rogers

Recent asteroseismic analysis of the main-sequence F star KIC 9244992 has revealed evidence for a strong, predominantly toroidal magnetic field in its deep radiative interior. Motivated by this result, we present three-dimensional anelastic magneto-hydrodynamic simulations of a rotating 2 solar mass main-sequence star to investigate whether such internal magnetic field strengths and geometries naturally arise in global stellar dynamo simulations for stars within a similar mass range. These simulations self-consistently generate magnetic fields with azimuthal components that dominate over radial components by factors of several near the peak of the Brunt-Vaisala frequency left behind as the core recedes. Moreover, these field strengths arise despite near-uniform, spherically-averaged, rotation from the near-core region to the surface. When the Reynolds number is greater than 100 and the appropriate Rossby number is used, the resulting field strengths and geometrical properties are consistent with those inferred asteroseismically for KIC 9244992. These results indicate that a dominant toroidal field in the near-core region is a generic field configuration in core-convecting stars and should be considered in future asteroseismic inferences.
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High Energy Physics (Theory)

Mirror symmetry on a circle

Siqi Chen, Shehab Hossam Fadda and Matteo Sacchi

We investigate the small circle, or high temperature, limit of the supersymmetric index identities for the three-dimensional abelian mirror symmetry of SQED. There exist two possible limits, depending on how the parameters of the theory are scaled with the radius of the circle. In both cases the result is qualitatively similar. One side always reduces to the sphere partition function of a two-dimensional $\mathcal{N}=(2,2)$ gauged linear sigma model (GLSM). The opposite side has a two-fold interpretation, either as the sphere partition function of the Landau–Ginzburg (LG) model that is Hori–Vafa dual to the GLSM, or as a Coulomb gas integral for a correlation function of Liouville or Toda CFT. This approach thus provides a systematic way to generate integral identities between partition functions of GLSMs on the one hand, and partition functions of LG models or CFT Coulomb gas integrals on the other. The latter perspective finds useful applications in the recently proposed 2d/2d correspondence, which relates sphere partition functions of unitary 2d $\mathcal{N}=(2,2)$ theories and correlation functions of non-unitary 2d CFTs that both descend from compactifications of a unitary 4d $\mathcal{N}=2$ SCFT. We present an example based on the $(A_{k-1},A_{N-1})$ Argyres–Douglas theories, where the CFT is a non-unitary minimal model. We also give a purely two-dimensional derivation of the identities obtained in the small circle limit which is inspired by the Kapustin–Strassler piecewise derivation of 3d abelian mirror symmetry.
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High Energy Physics (Theory)

A note on the quantization of angular momentum for black holes

Jon Goker, Luca V. Iliesiu and Elisa Tabor

We argue that the gravitational path integral for rotating black holes is periodic in the angular velocity, implying the quantization of angular momentum in arbitrary dimensions for either asymptotically flat or AdS boundary conditions. In AdS$_3$, this periodicity is a consequence of the boundary mapping class group. In higher dimensions, the periodicity arises from an infinite family of saddles labeled by integer shifts of the angular velocity unrelated to the boundary mapping class group; summing over these saddles enforces quantization independently of any large boundary diffeomorphism. We construct these saddles explicitly for Kerr-Newman black holes in both asymptotically flat space and AdS$_4$, and observe that even the path integral for the 4D Schwarzschild black hole, typically the simplest case, receives contributions from an infinite set of rotating saddles.
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General Relativity and Quantum Cosmology

Constraints on regular black holes with nonminimally coupled electromagnetic fields

Ana Bokulić, Tajron Jurić, Luka Kanai Pejić et al. (+2 more)

Construction of physically realistic theories admitting regular black hole solutions remains an important open problem in gravitational physics. While theories with electromagnetic fields minimally coupled to gravity have been extensively studied over the past two decades, theories with nonminimal couplings remain comparatively unexplored. We investigate theories containing the interaction terms $R F_{ab}F^{ab}$, $R_{ab} F^a_{\ \, c} \, F^{bc}$ and $R_{abcd} F^{ab} F^{cd}$, which generically arise in low-energy effective Lagrangians. We prove that magnetically charged regular black holes are excluded, except possibly for finely tuned choices of coupling constants, and argue that a similar conclusion applies to electrically charged regular black holes. We further show that similar conclusions hold for Lagrangian terms of the form $f(R,F_{ab}{\star F}^{ab})$.
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All authors Ana Bokulić, Tajron Jurić, Luka Kanai Pejić, Filip Požar, Ivica Smolić

Quantum Gases

Digital programming of spin correlations in a fermionic lattice quantum simulator

Yann Kiefer, Lars Fischer, Zijie Zhu et al. (+2 more)

Analog quantum simulation provides a highly controlled platform to study diverse quantum many-body phenomena. However, current methods for state initialisation are limited to thermal ensembles or uncorrelated product states. Here we present a hybrid approach that complements analog preparation with a digital quantum-gate protocol. This approach enables the engineering of target states with specific, long-range spin-correlations from the same initial resource state. By applying collisional gates to adiabatically prepared and filtered four-fermion singlet chains, we program diverse spin-correlation patterns, including that of a Heisenberg chain. We measure the spin correlations using a sequence of quantum gates followed by singlet-pair measurements. Our method paves the way to the targeted preparation of strongly correlated states of matter.
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All authors Yann Kiefer, Lars Fischer, Zijie Zhu, Konrad Viebahn, Tilman Esslinger

High Energy Physics (Theory)

Bootstrapping Euclidean Lattices

Francesco Bertucci and James Bonifacio

We derive spectral identities involving the Laplace spectrum and the integrals of products of eigenfunctions on flat tori and orbifolds. Using semidefinite programming, we derive upper bounds on sums of squares of triple products from these spectral identities, following the approach of the conformal bootstrap. Physically, these upper bounds give constraints on sums of squares of cubic coupling constants in toroidal compactifications of higher-dimensional field theories. For Euclidean lattices, one of the bootstrap bounds leads to an upper bound on the mean square number of minimal vectors that are minimal distance from each minimal vector, divided by the kissing number of the lattice. By finding exact functionals for the semidefinite programming problems, we prove that this bound is saturated in 2, 4, 8, and 24 dimensions by the hexagonal lattice, the $D_4$ lattice, the $E_8$ lattice, and the Leech lattice, respectively.
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High Energy Physics (Theory)

4d CFT Correlators from Ambitwistors

Mariana Carrillo González and Théo Keseman

We develop an ambitwistor-space formulation of conserved spinning correlators in four-dimensional CFTs. We show that conformal symmetry and conservation are trivialised by the ambitwistor Penrose transform, and construct the two- and three-point ambitwistor correlators explicitly. We further propose a simple formula for projecting onto parity-even and parity-odd sectors, and verify it in several non-trivial examples. The resulting correlators furnish a natural basis compatible with a boundary double copy for arbitrary spin. At three points, we show that they localise on degree-three curves in a two-twistor representation. We also explain how the formalism incorporates boundary propagators for unitary operators of integer conformal dimension, and extend it to conformally coupled scalars.
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Materials Science

Electrostatic Charge Model for Dual-Layer Oxide Thin-Film Transistors

Måns J. Mattsson, John F. Wager and Matt W. Graham

A simple electrostatic two-equation model for dual-layer thin-film transistor (TFT) operation is developed. The model distributes electrostatic charge between the top and bottom semiconductor layers, and the resulting transfer and mobility curves accurately simulate experimental dual-layer a-IGZO/a-IZO TFT operation. The model further provides an analytic expression that maps charge confinement in the high-mobility a-IZO bottom semiconductor layer with the a-IGZO top-layer thickness and the conduction-band offset. By considering both a-IGZO/a-IZO layer charge partition and competing thickness-dependent oxygen vacancy trap density effects, the model suggests an optimal a-IGZO layer thickness of 9 to 12 nm. Importantly, this general electrostatic model extends to most dual-layer TFT systems and calculates how the top semiconductor layer TFT turn-on voltage changes sharply with the conduction band offset and layer thickness.
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High Energy Astrophysical Phenomena

IceCube Real-time Searches for High-energy Neutrinos Coincident with LIGO/Virgo/KAGRA Gravitational-Wave Alerts in O4a

The IceCube Collaboration: R. Abbasi, M. Ackermann, J. Adams et al. (+417 more)

Gravitational-wave events from mergers of compact objects are a predicted source of high-energy neutrinos. Using data from the IceCube Neutrino Observatory, we search for neutrinos coincident with 85 significant and 945 low-significance gravitational-wave candidate events from compact binary coalescences published in real-time by the LIGO-Virgo-KAGRA collaboration during the first part of its fourth observing run (O4a) and its preceding engineering run, within a time window of $\pm500$ seconds from the merger time. We report improvements to the online pipelines, including automatic sending of notices, which improved the median IceCube real-time response compared to the previous observing run by a factor of 2.7 times faster. In addition, we search for long-duration neutrino emission from three candidate events: two neutron star-black hole mergers and one low-significance gravitational-wave event with a possible subthreshold gamma-ray counterpart. We use two methods, both of which have been previously used to search for neutrinos from gravitational-wave transients: an unbinned maximum likelihood analysis on significant alerts and a Bayesian analysis accounting for astrophysical priors on all alerts. We find no statistically significant emission from any individual gravitational-wave event analyzed. In the unbinned maximum likelihood search, the lowest $p$-value event is S231029y, with $p=0.0079$ ($0.752$ post-trials). In the Bayesian search, the lowest $p$-value for significant events is S230904n, with $p=0.0076$ ($0.9996$ post-trials), and for low-significance events is S231025a, with $p=0.0011$ ($0.678$ post-trials), with an overall population $p$-value of $0.55$. We accordingly set upper limits for each event on the time-integrated flux and energy emitted in neutrinos, assuming isotropic emission.
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All authors The IceCube Collaboration: R. Abbasi, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, J.M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argüelles, Y. Ashida, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., S. W. Barwick, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, P. Behrens, J. Beise, C. Bellenghi, S. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, L. Brusa, R. T. Burley, D. Butterfield, K. Carloni, J. Carpio, N. Chau, Y. C. Chen, Z. Chen, D. Chirkin, S. Choi, A. Chubarov, B. A. Clark, G. H. Collin, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. Díaz-Vélez, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, C. Eldridge, P. Eller, E. Ellinger, D. Elsässer, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, K. M. Groth, D. Guevel, C. Günther, P. Gutjahr, C. Ha, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, A. Hollnagel, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jin, N. Kamp, D. Kang, W. Kang, A. Kappes, L. Kardum, T. Karg, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, T. Kim, H. Kimku, F. Kirchner, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, S. Koch, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyńska, C. Li, J. Liao, C. Lin, Q. R. Liu, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, D. Mousadi, E. Moyaux, T. Mukherjee, M. Nakos, U. Naumann, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, B. Owens, V. Palusova, H. Pandya, A. Parenti, N. Park, V. Parrish, E. N. Paudel, L. Paul, C. Pérez de los Heros, T. Pernice, T. C. Petersen, J. Peterson, S. Pick, M. Plum, A. Pontén, V. Poojyam, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, S. Rodan, M. J. Romfoe, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, M. Scarnera, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, A. Scholz, F. G. Schröder, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, S. Shefali, N. Shimizu, M. Shin, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, D. Song, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, K. Tollefson, J. A. Torres, S. Toscano, D. Tosi, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Velazquez, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, R. Young, F. Yu, S. Yu, T. Yuan, S. Yun-Cárcamo, A. Zander Jurowitzki, A. Zegarelli, A. Zhang, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, C. Zilleruelo Cañas

Astrophysics of Galaxies

On the survival of dark matter spikes: Stellar and compact-object perturbations

Theophanes K. Karydas, Francesca Scarcella, Bradley J. Kavanagh et al. (+1 more)

Establishing realistic expectations for the dark matter (DM) distribution near a supermassive black hole (BH) is essential for assessing environmental imprints on gravitational wave (GW) signals. Using the Galactic Center as an observationally constrained case study, we investigate the evolution of DM density spikes under gravitational perturbations from the nuclear stellar and black hole populations surrounding the central BH. We find that scattering of DM particles by the nuclear star cluster depletes the DM distribution at radii $r \sim 10^{-1}~\mathrm{pc}$, far outside the region where the relevant GW signals are produced. At smaller radii, at $r \sim 10^{-3}~\mathrm{pc}$, the closest known stellar perturbers, S2 and S38, induce only negligible changes to the density profile. At still smaller radii, where no stellar perturbers are currently known, we assess the cumulative impact of past EMRIs by modelling successive mergers with stellar-mass BHs of mass $\sim10~\mathrm{M}_\odot$, in numbers consistent with the expected rate over $10~\mathrm{Gyr}$. We find that these events do not erase the central overdensity, reducing the density only to approximately $82 \%$ of its initial value at $r \lesssim 10^{-5}~\mathrm{pc}$. Our results indicate that, at least at the Galactic Center, DM overdensities around the central BH are expected to remain largely intact under stellar perturbations and plausible stellar-BH merger histories.
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All authors Theophanes K. Karydas, Francesca Scarcella, Bradley J. Kavanagh, Gianfranco Bertone

Quantum Physics

Tantalum as a base material for superconducting integrated circuits

Evgeniy V. Zikiy, Nikita S. Smirnov, Stanislav A. Kotenkov et al. (+9 more)

The performance of superconducting integrated circuits for quantum applications is fundamentally limited by material-related losses. Tantalum, as an emerging material for next-generation quantum circuits, has attracted considerable attention in recent years after demonstrating breakthrough performance in both superconducting microwave resonators and qubits. Concurrently, a growing body of work is devoted to the operation of tantalum-based circuits and related fabrication techniques. This interest is further stimulated by tantalum thin films polymorphism resulting in a variety of its crystalline structure, superconducting properties, coherence, etc. Furthermore, tantalum circuits exhibit distinctive features in cryogenic experiments, which have not been observed in aluminum- or niobium-based ones. In this review, we summarize the recent research of tantalum thin films growth and phase selection mechanisms on various substrates, key aspects of fabrication and performance of superconducting circuit, including a material first-principles theoretical study. In conclusion, we address a number of open issues, including the role of e̱ta}-phase impurities, the effect of hydrofluoric acid solutions on chain characteristics, and the anomalous behavior of {\alpha}-tantalum chains at cryogenic temperatures.
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All authors Evgeniy V. Zikiy, Nikita S. Smirnov, Stanislav A. Kotenkov, Ilya A. Stepanov, Julia A. Agafonova, Daria A. Moskaleva, Aleksei R. Matanin, Anton I. Ivanov, Dmitry O. Moskalev, Julia A. Kurochkina, Aleksander V. Andriyash, Ilya A. Rodionov

Accelerator Physics

Intrabeam scattering studies with large-emittance-ratio ion beams in the Relativistic Heavy Ion Collider, and implications for the Electron-Ion Collider

Yun Luo, Brendan Lepore, Kevin Mernick et al. (+2 more)

The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory, will collide polarized, high-energy electron beams with hadron beams, achieving peak luminosities of up to $1.0 \times 10^{34}$ cm$^{-2}$ s$^{-1}$. To reach such luminosity, the EIC will employ flat-beam collisions at the interaction point. The design transverse emittance ratio will be about 10:1 in the Hadron Storage Ring (HSR). Thanks to stochastic cooling and precise decoupling, we successfully generated and accelerated gold ion beams with a large emittance ratio of 11:1 in the Relativistic Heavy Ion Collider (RHIC). In this article, we present results of intrabeam scattering (IBS) measurements and modeling for large-emittance-ratio gold ion beam, both with and without controlled betatron coupling. To model the IBS growth, we use the formulas developed by Lebedev and Nagaitsev.
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All authors Yun Luo, Brendan Lepore, Kevin Mernick, William Bergan, Sergei Nagaitsev

Computational Physics · Cross-listed from cs.LG

A fully GPU-based workflow for building physics emulators of hypersonic flows

Fabian Paischer, Dylan Rubini, Deniz A. Bezgin et al. (+6 more)

The ability to resolve complex physical phenomena with high fidelity and at low computational cost is central to addressing key challenges in modern engineering. A prime example lies in hypersonic flows, where the precise prediction of the full flowfield topology, in particular with respect to shock wave location and intensity, is critical. Yet supersonic and hypersonic flows continue to be a stumbling block for traditional reduced-order models and neural emulators that struggle to capture steep gradients in flow states with physical consistency in applications of industrial relevance. To that end, we introduce a fully GPU based workflow that integrates accelerated data generation with the training of neural emulators augmented by uncertainty quantification and physics-aware refinement. Our workflow is enabled by a differentiable high-fidelity solver (JAX-Fluids) which we employ for rapid dataset creation and residual-based improvement of the neural emulator to enhance physical consistency. Building on this framework, we first present a suite of model architectures and analyze their scaling behavior to expose their strengths and shortcomings. We then show that residual-based refinement enables training on cases where only mesh and input parameters are available, substantially reducing residuals and improving physical consistency. Together, differentiable simulation and residual-based refinement yield physics emulators that remain reliable beyond their training distribution, a key requirement for deploying surrogates in real-world engineering design loops.
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All authors Fabian Paischer, Dylan Rubini, Deniz A. Bezgin, Aaron B. Buhendwa, David Hauser, Florian Sestak, Johannes Brandstetter, Sebastian Kaltenbach, Nikolaus A. Adams

General Relativity and Quantum Cosmology

SPLIT: Loosely-coherent inference of long-inspiral gravitational-wave sources for robustness against modeling and data outliers

Shubham Kejriwal

The Laser Interferometer Space Antenna (LISA) will detect gravitational waves (GWs) from dozens of extreme- and intermediate-mass-ratio inspirals (EMRIs/IMRIs). These sources will stay in-band for months to years, offering extraordinary scientific potential. However, their fully phase-coherent analysis standard in current pipelines imposes stringent waveform accuracy requirements; failing to model the signal over such long durations can result in significant systematic biases. To address this, we formulate a robust Bayesian inference framework that segments the data into blocks, infers each block coherently, and recombines the results using loosely-coherent phase information. By restricting full phase-tracking to much shorter block durations, this approach prevents significant accumulation of phase errors. We implement this methodology in SPLIT (Segmented Posteriors for Long-Inspiral Templates), a GPU-accelerated Python package. Applying SPLIT to an environment-rich injection, we demonstrate that while a fully-coherent vacuum-GR analysis incurs a maximum 1D systematic bias of $\approx 4.8\sigma$ from the truth, the shorter integration window of our loosely-coherent approach restricts such biases to $\lesssim 0.5\sigma$. Overall, despite a fractional loss of optimal signal-to-noise ratio, the substantial improvement in parameter accuracy offered by our method presents a highly advantageous trade-off for LISA and other future GW detectors.
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General Relativity and Quantum Cosmology

High-Precision Relativistic Time Scales for Mars Surface and Orbital Clocks

Slava G. Turyshev

We develop a Mars-centered post-Newtonian framework for relating barycentric coordinate time, Mars-centered coordinate time, a conventional Mars surface time scale, and the proper times of landed and orbiting clocks. The construction follows the International Astronomical Union BCRS/TCB formalism, introduces Areocentric Coordinate Time (TCA), and writes each clock transformation as a secular rate plus zero-mean periodic terms. Terms are retained when their fractional-frequency amplitude exceeds 5e-18 or their one-way accumulated timing amplitude exceeds 0.1 ps. The numerical realization uses the GMM-3 Mars gravity field through degree and order 120, point-mass tides from the Sun, Phobos, and Deimos with origin and dipole terms removed, and bounds on omitted local c^-4 and external-perturber terms. Representative low-Mars-orbit, areostationary, Phobos-/Deimos-distance, and highly elliptical relay regimes are evaluated. Relative to the adopted Mars surface scale, a 300 km near-polar clock is slower by 4.56 microseconds per day, while areostationary and Deimos-distance clocks are faster by 9.13 and 9.52 microseconds per day. The leading Mars-J2 timing line is about 87 ps at 300 km altitude and remains several ps near areostationary radius for inclined or librating areosynchronous cases; perihelion-scaled solar tides become retained sub-ps terms in high relay orbits. The result is a reference-system and model-retention framework, not a final operational Mars Time Ephemeris. A realized sub-ps system still requires a selected planetary ephemeris, Mars orientation and seasonal-gravity model, spacecraft orbit determination, calibrated link delays, and covariance analysis. Time-variable low-degree gravity from seasonal CO2 exchange is a leading surface-realization term and must be modeled, monitored, or empirically bounded before sub-ps Mars surface-scale claims are made.
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High Energy Physics (Phenomenology)

Dynamical Mass Growing of Fermion with Bare Mass in Two Dimensions

Toyoki Matsuyama

We study dynamical mass generation of a fermion with and without a bare mass by coupling with a massive vector field in two-dimensional space-time. To estimate a non-perturbative effect on the fermion mass, we employ the Schwinger-Dyson equations in the lowest-ladder approximation, which are solved by an approximated analytical method and also by a numerical method. We define a purely dynamical mass as a remnant after subtracting the bare mass from a total dynamical mass. We clarify dependence of the purely dynamical mass on the bare mass of the fermion in various region of a coupling constant. Especially we find that the purely dynamical masses growing from the different bare masses coincide with each other at a specific value of the coupling constant where a kind of a duality relation on the bare masses is satisfied.
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2606.13724 · 11 Jun · This is a posthumous paper submitted with the permission of the author's family, Yoko Matsuyama. K. Nakatsugawa, S. Tanda, and G. E. Volovik examined the manuscript and recognized its scientific value, judging it worthy of archival publication as a contribution to physics. S. Tanda and K. Nakatsugawa further verified its content on behalf of the author to ensure its accuracy

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Soft Condensed Matter

Controlling Defects and Probing Dynamics in Active Nematics with Deep Reinforcement Learning

Russ Islam, Kyogo Kawaguchi and Yuto Ashida

Topological defects govern much of the flow behavior and orientational order in active nematics, making their control relevant for active matter physics, smart materials, and microfluidics. Applied activity patterns can induce self-propulsion of active nematic defects, but general-purpose methods for exploiting this effect to control defects remain largely unexplored. Here we use deep reinforcement learning (RL) to perform minimum-time position control of +1/2 defects in hybrid lattice Boltzmann simulations of active nematodynamics. Spatiotemporally patterned activity, implemented as a control field in the active stress, steers defects through microchannel geometries and reveals finite-time reachable regions of defect position space. Reachability is shaped by director anisotropy, homeotropic wall anchoring, and the allowed activity patterns: local patterns steer defects in free domains but fail in junctions, whereas global patterns open otherwise inaccessible channels. In constrained geometries, the original defect may be unable to reach some goals intact, but controlled pair creation enlarges the effective reachable set by transferring control to a newly created +1/2 defect. The trained RL controllers outperform static and rule-based baselines, and controllers trained only on simple junctions can be combined without fine-tuning into a meta-controller that successfully steers defects through a larger test maze. Free energy visualizations show that guided defects write persistent, history-dependent distortions into the director field that can later be partially erased by -1/2 defects. Thus, RL-based control uncovers how confinement, anchoring, actuation geometry, and defect creation determine reachable motion in active nematics, providing a framework for other control tasks in soft and active matter.
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General Relativity and Quantum Cosmology

Decoding the Gravitational Geometry and Stellar Photometric Profiles of Galaxy NGC 7331

Aritra Sanyal Bikramarka S. Choudhury Farook Rahaman

Galaxy rotation curves provide a powerful probe of mass distributions in spiral galaxies. We present a general relativistic analysis of NGC 7331 using its observed rotation curve and WISE W1 (3.4 $\mu$m) photometry to constrain the stellar mass profile. Adopting a static, spherically symmetric spacetime with anisotropic matter (vanishing radial pressure), we fit a modified exponential azimuthal velocity law to kinematic data, reconstructing metric functions and deriving enclosed mass, energy density, and tangential pressure profiles. The stellar mass underpredicts the total gravitating mass at intermediate-to-large radii, indicating dominant dark matter. The physical viability of the resulting relativistic model is examined through energy conditions, causality constraints, and the stability of circular orbits. A comparison with the standard Navarro–Frenk–White dark matter profile has been done. Overall, this study demonstrates that combining rotation-curve data with photometric stellar mass estimates within a general relativistic framework provides a consistent and physically viable description of the mass distribution in spiral galaxies such as NGC~7331.
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General Relativity and Quantum Cosmology

Non-Markovian Memory-Induced Effects in Quantum Cosmology

Aarav Shah, Paulo Moniz, Oem Trivedi et al. (+1 more)

We study memory effects in quantum cosmology by extending the semiclassical Wheeler-DeWitt framework beyond its usual local form. The main idea is to introduce a causal memory kernel at sub leading order, rather than imposing fractional derivatives directly by hand. In this setting, fractional time evolution appears as an effective description of the underlying nonlocal dynamics. We apply the framework to cosmological perturbations in de Sitter space and find a correction to the primordial power spectrum with a characteristic $k^{3/4}$ scaling. This contribution mainly affects high $l$ CMB temperature anisotropies, in contrast with standard semiclassical quantum gravitational corrections, which are strongest at large angular scales. We also discuss how the same memory-dependent dynamics may affect primordial non-Gaussianity, producing scale dependent corrections to the bispectrum and possible deviations from the usual squeezed limit consistency relation. Since the memory coefficient controls short scale power, it may also influence structure formation and could require some tuning in order to give phenomenologically acceptable astrophysical environments. Finally, we suggest that a cyclic extension of the Hawking-Hartle no-boundary proposal may provide a setting in which the effective memory strength can evolve across successive cosmological histories. In this way, the framework gives a concrete realization of fractional quantum cosmology based on memory effects and also points to possible observational signatures of nonlocal quantum gravitational dynamics.
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All authors Aarav Shah, Paulo Moniz, Oem Trivedi, Meet J. Vyas

Physics and Society

A model of local and global reciprocity

Mari Kawakatsu, Yohsuke Murase, Taylor A. Kessinger et al. (+1 more)

We often decide how to treat friends based on observations of their past behavior, whereas actions toward strangers are typically guided by their public reputations. These two kinds of information underlie two classical mechanisms for the evolution of cooperation$\unicode{x2014}$direct and indirect reciprocity$\unicode{x2014}$which have largely been studied in isolation. They are not interchangeable: we can recall the past actions of only a small circle of close contacts, whereas for the far larger pool of strangers we must rely on public reputations. Here we develop a mathematical framework built on this distinction. Each individual engages in direct reciprocity in local games within a finite neighborhood of friends, whose actions they observe directly, and in indirect reciprocity in global games with a large population of strangers, known only by reputation. Separating local and global interactions allows us to address two questions. First, can cooperation persist under a cognitively simple norm of judgment? We show that combining direct and indirect reciprocity resolves the scoring dilemma: conditional cooperators resist invasion by both unconditional cooperators and unconditional defectors, where indirect reciprocity alone would fail. Second, how should one treat a friend whose past behavior conflicts with their public reputation? We find that the strategies that maximize cooperation are forgiving$\unicode{x2014}$overlooking whichever piece of information is unfavorable$\unicode{x2014}$and that these forgiving strategies can often remain robust to invasion. By distinguishing between local and global scales of interaction and integrating information across them, our framework offers a more cognitively realistic account of how reciprocity sustains cooperation.
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All authors Mari Kawakatsu, Yohsuke Murase, Taylor A. Kessinger, Joshua B. Plotkin

Quantum Physics

Semi-Device-Independent Certification for Nonlocality without Entanglement

Hanwool Lee and Joonwoo Bae

In this work, we present the framework for demonstrating and certifying the distinction between measurements in an entangled basis, called global measurements, and local operations and classical communication (LOCC), known as nonlocality without entanglement (NLWE). To be precise, we show NLWE via a maximum-confidence measurement in terms of a guess per detection event, called a confidence, a fine-grained guessing probability that encompasses both minimum-error and unambiguous state-discrimination strategies. We show that NLWE for unknown measurements can be certified, given the measurement-outcome rates, by bounding the confidence using LOCC; the certification is semi-device-independent in that state preparation is trusted. We illustrate the demonstration and certification of NLWE for antiparallel qubit states. Our results make it feasible to experimentally realize NLWE using measurement devices with imperfections, such as non-unit detection efficiency, since maximum-confidence measurements rely only on detected events.
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Astrophysics of Galaxies

Centrally concentrated star formation in young clusters II: Jet feedback

Adilkhan Assilkhan, Sabrina M. Appel, Bekdaulet Shukirgaliyev et al. (+5 more)

Protostellar jets are one of the earliest forms of stellar feedback, but their impact on star formation and cluster assembly in centrally concentrated molecular clouds remains poorly understood. We study how protostellar jets affect the star formation efficiency, the temporal variability of star formation, star cluster structure, and the early dynamical state of centrally concentrated, newly forming star clusters using the Torch star cluster formation framework. We adopt a centrally concentrated initial cloud model with mass M = 2.5 x 10^3 solar masses and compare six pairs of simulations with and without protostellar jets, supplemented by one additional higher resolution pair of simulations. We analyze our simulations using global star formation diagnostics together with structural and dynamical measures of the stellar population. Models with jet feedback achieve star formation efficiencies of 12-16%, while the corresponding models without jets yield higher efficiencies of 19-33%. Jets also cause star formation to occur in discrete bursts rather than continuously, to produce more extended and substructured stellar systems, and to leave behind stellar populations that are less tightly bound and have higher virial parameters. In our centrally concentrated initial conditions, runs with jets form stellar systems that better reproduce the observed range of the projected structural parameter Q_2D in young clusters than runs without jets, indicating that protostellar jets are an important early feedback channel even in centrally concentrated clouds that regulates star formation efficiencies and shapes the emerging cluster structure.
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All authors Adilkhan Assilkhan, Sabrina M. Appel, Bekdaulet Shukirgaliyev, Ernazar Abdikamalov, Simon Portegies Zwart, Eric P. Andersson, Mukhagali Kalambay, Mordecai-Mark Mac Low

High Energy Physics (Theory)

One-loop five-point gluing analytically

B. Eden and M. Gottwald

The one-loop five-point function of stress tensor multiplets in N=4 super Yang-Mills theory in four dimensions has previously been studied by integrability methods. The finite-size viz gluing corrections defining it were originally matched on the known field theory result - establishing many features of the formalism on the way - and later to a good extent also analytically evaluated. For the first time, we present a full analytic evaluation of all processes. The starting point is the re-summation of series of residues into Euler integrals. These are directly integrated where possible or otherwise recovered from intersection theory for generalised hypergeometric functions.
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Materials Science

Morphology control and low-temperature magnetotransport in chiral 2D perovskite R-(MBA)$_2$PbI$_4$

Shehreen Aslam, Sam Saiter, Bradley Lloyd et al. (+4 more)

Two-dimensional chiral hybrid perovskites, such as R/S-(MBA)\textsubscript{2}PbI\textsubscript{4}, are leading candidates for realizing and studying chirality-dependent charge and spin transport. However, their prohibitive in-plane resistance has precluded the electrical characterization. Here, we overcome this bottleneck by engineering the thin-film morphology of the chiral perovskite $R\text{-(MBA)}_2\text{PbI}_4$, enabling the first robust lateral device integration. In Hall-bar geometries, we demonstrate Hall measurements under dark conditions, unambiguously identifying p-type conduction with a Hall mobility of $\sim 0.2 \text{cm}^2 \text{V}^{-1} \text{s}^{-1}$ and a carrier density of $\sim 3\times10^{14} \text{ cm}^{-2}$, parameters previously inaccessible in this class of materials. Furthermore, we observe enhanced magnetoresistance along transport paths crossing grain boundaries, highlighting the strong influence of morphology on in-plane transport. This work demonstrates in-plane magnetotransport, enabling future investigations of the fundamental mechanisms of chirality-induced spin selectivity (CISS) and accelerating the integration of chiral materials into functional spintronic devices.
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All authors Shehreen Aslam, Sam Saiter, Bradley Lloyd, Paul Kliewer, Matthew P. Hautzinger, Matthew C. Beard, Meenakshi Singh

Plasma Physics

Robust Control of ECH Deposition Profiles on DIII-D

H.J. Farre-Kaga, A. Rothstein, K. Yasoda et al. (+5 more)

Electron Cyclotron Heating (ECH) is a key actuator in DIII-D and future tokamaks that provides auxiliary heating, localized current drive for scenario development and MHD stability, and even impurity pump-out. Due to its control flexibility and applications, a gyrotron optimization algorithm was developed to multitask and fine-tune the deposition location and heating power of each gyrotron while providing robustness to hardware failure. The ECH Optimization (ECHO) algorithm finds the optimal gyrotron mirror angle and power to achieve a target ECH radial deposition profile. This optimization is accomplished in real-time using a parallelized neural network surrogate of the TORBEAM code combined with a genetic optimizer. This has been deployed in a DIII-D experiment and has been validated with experimental ECE measurements and post-experiment offline ray tracing, showing the algorithm's reliability despite gyrotron failures and significant changes to plasma parameters.
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All authors H.J. Farre-Kaga, A. Rothstein, K. Yasoda, J. Lestz, N. Chen, S.K. Kim, A. Jalalvand, E. Kolemen

Chemical Physics

Spin-Polarized Oxygen Evolution in Chiral-Molecule-Modified Plasmonic Photoanodes

Priscila Vensaus, Milad Sabzehparvar, Fatemeh Kiani et al. (+2 more)

Photoelectrochemical oxygen evolution is limited not only by multi-electron charge-transfer kinetics but also by the spin constraints associated with forming triplet O2. Here, we used a hybrid photoanode architecture to demonstrate spin-polarization of plasmonic hot holes through a chiral molecular layer. TiO2 photoanodes were modified with achiral Au nanoparticles to introduce visible-light plasmonic absorption, functionalized with cysteine as a chiral molecular interface, and coated with a NiFe-based oxygen-evolution catalyst. Wavelength-resolved photo-scanning electrochemical microscopy was used to directly detect locally evolved O2 under operando illumination while simultaneously monitoring the photoanode current. Chiral functionalization with homochiral L-cysteine enhanced both photocurrent and local O2 evolution relative to racemic DL-cysteine controls. The chirality-dependent enhancement was most pronounced under visible excitation overlapping the Au plasmon resonance, including a 130% photocurrent increase. These results provide evidence that chiral molecular layers, often used for chiral nanoparticle synthesis, can directly modulate plasmon-derived hot-carrier transfer through the chiral induced spin selectivity (CISS) effect. This work establishes a chiral plasmonic photoelectrochemical platform for coupling hot-carrier generation to spin-dependent water oxidation.
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All authors Priscila Vensaus, Milad Sabzehparvar, Fatemeh Kiani, Germán García Martínez, Giulia Tagliabue