Papers

The Dicke model provides a fundamental description of collective light-matter interactions and has long served as a testbed for exploring a wide range of physical phenomena in quantum optics and condensed matter physics. In this work, we develop a variational framework for investigating the finite-size Dicke model on both fully qubit-based (digital) and hybrid qubit boson based (digital-analogue) quantum computing platforms. We show that the resulting model reproduces the characteristic critical behavior of the Dicke model in the appropriate large-spin limit while remaining suitable for implementation on both classical emulators of quantum computers and actual trapped ion quantum computers, albeit in the case of latter somewhat limited by noise. Finally, we introduce a complementary hybrid qubit-bosonic variational ansatz that directly exploits the bosonic degree of freedom to reduce quantum resources and discuss its potential implementation on hybrid quantum hardware. Our results establish a scalable, symmetry-aware framework for variational quantum simulations of collective light-matter systems and provide a pathway toward efficient simulations of more general spin-boson models on near-term quantum devices.

We investigate the dissipative dynamics of a generalized Lipkin-Meshkov-Glick (LMG) model coupled to a thermal environment. In this generalized model, in addition to the conventional quadratic interaction, one considers quartic interactions between spin-$1/2$'s coupled all-to-all and evolving in presence of a transverse field. Employing the usual linear Lindblad master equation with thermally-balanced jump processes, we derive magnetisation evolution equations, and demonstrate that the corresponding stationary solution reproduces the canonical equilibrium phase diagram of the model. We then extend our analysis to a nonlinear Lindblad equation that incorporates imperfect quantum-jump processes in terms of jump-retention parameters. Here, remarkably, the system relaxes to a genuine nonequilibrium stationary state whose properties differ qualitatively from those obtained in the linear case. The jump-retention parameters provide tunable knobs that shift the phase boundaries and even modify the nature of the phase transitions with respect to the linear case. Our exact results establish a direct connection between dissipative relaxation dynamics and stationary-state behavior, while identifying controlled quantum-jump retention as a mechanism for engineering nonequilibrium phases in long-range interacting open quantum systems.

We study the generation of state $k$-designs from time evolution under a fixed Hamiltonian. Specifically, we consider the ensemble $\mathcal{E}=\left\{e^{-iHt}|\psi_0\rangle | \ t\sim \mathrm{Unif}[0,T],\, |\psi_0\rangle\sim \mathcal{E}'\right\}$, where the initial states are sampled from an ensemble $\mathcal{E}'$. For Hamiltonians drawn from the Gaussian unitary ensemble, we derive a simple relation between the frame potential of the evolved ensemble $\mathcal{E}$ and that of the initial ensemble $\mathcal{E}'$ in the large evolution time limit. This relation shows that $\mathcal{E}$ forms an exact state $k$-design in the thermodynamic limit as long as $\mathcal{E}'$ forms a state 1-design. Remarkably, we further show, both analytically and numerically, that time evolution under a simple nonintegrable mixed-field Ising Hamiltonian can generate approximate state $k$-designs with high precision, starting from product states in an appropriately chosen Pauli basis. We also analyze the finite-$T$ correction and find it scales as $O(1/T)$. To reduce the evolution time, we propose an $M$-step quench protocol that suppresses this correction to $O(1/T^M)$, which is also verified numerically. We then extend our analysis to unitary ensembles, deriving an analogous recursion relation for the unitary frame potential. Our results elucidate the mechanisms underlying recent proposals for generating unitary $k$-designs through sequential quantum quenches in a unified manner.

Photons in ultra-peripheral collisions of heavy ions (and protons) can be used for a variety of physics purposes - for studies of nuclear structure at low Bjorken$-x$, as probes of beyond-standard-model physics at the highest possible photon energies, and to explore new regimes of quantum mechanics via interferometry between two photon sources that share no common origin. This review will present the origins of photons in ultra-peripheral collisions and discuss the important physics that is being done with these photons, with particular emphasis on those on the energy frontier for photon physics.

Primordial black holes (PBHs) evaporate through Hawking radiation, emitting high-energy photons and ionising their surrounding environment. As contributors to the density of dark matter, Omega_C, if 10^-18 solar mass PBHs are present in the Universe they delay recombination and move the surface of last scattering of the cosmic microwave background (CMB). We perform recombination simulations using the software Recfast, and calculate the PBH fraction of dark matter required to resolve the Hubble tension. We find that nominally a cosmic PBH energy density of Omega_PBH ~ 10^-3 Omega_C would cause an 8.9% increase in the value of H_0, enough to entirely reduce the tension between the early- and late-time observations. This PBH fraction is modified by Gray Body Factors affecting Hawking radiation. Furthermore, also fitting the CMB leaves the Hubble tension not fully relieved with our present PBH prescription. Until relevant non-gravitational properties of the dominant dark matter species are ruled out, we suggest that the hypothesis that the ionisation history of the universe matches the thermal history of the standard LCDM cosmology is too precarious to hang the expansion rate on, and that it is better to measure H_0 locally at z <~ 1.

The construction of machine-learned interatomic potentials (MLIPs) is often limited by the cost of generating large density-functional-theory (DFT) training datasets. For systematically generated structure pools such as ASSYST, a central practical question is how many configurations must be labeled to achieve reliable accuracy. Here we assess geometry-based, label-free subset selection for training linear Atomic Cluster Expansion (ACE) potentials. Using statistical leverage scores and CUR-type sampling, we compare leverage-guided selection against random, energy-based, and force-based baselines under controlled iterative protocols. Elemental Al provides the primary benchmark, with Cu and Al-Cu alloys used for transfer validation. Leverage-guided subsets recover plateau-level energy and force accuracy using substantially smaller labeled fractions (approximately 30-40%) than random sampling, corresponding to an effective 2-3x reduction in DFT labeling for the systems studied. In alloy tests, defect energetics remain comparable across strategies once sufficient chemical diversity is included, while leverage selection maintains competitive accuracy at reduced training size. These results demonstrate that descriptor-space-guided, label-free subsampling can significantly reduce DFT workload for linear ACE models trained on ASSYST structure pools without degrading defect-level fidelity.

Chondrites are composed of formerly partially molten material, known as chondrules, surrounded by fine-grained matrix. They date from the earliest times in Solar System history. However, their role in the formation of the planets is uncertain because, in part, it is not clear how they were produced. Here, we show a robust pathway for forming meteorite-producing asteroids that contain chondrules through embryo-embryo collisions during the late stages of terrestrial planet formation. Melted material from these impacts cool into chondrules and mix with unmelted material in embryo-centric disks that formed from the ejecta. This material accretes into numerous asteroid-sized satellites. These objects are later ejected onto heliocentric orbits because of gravitational encounters with other embryos, thereby becoming the parent bodies of chondrites. This mechanism provides a pathway to form chondrites in Solar System history at times commensurate with measured chondrule ages, while explaining many of their physical properties.

We constrain the class of modified cosmologies derived in Paper I [1] from a generalized mass-to-horizon relation (MHR) that enforces thermodynamic consistency between the Cai-Kim horizon temperature and generalized horizon entropies. The modified Friedmann equations depend on an entropy exponent $m$, an MHR coupling parameter $\gamma$, and an entanglement-correction amplitude $f_B$, with standard $\Lambda$CDM recovered in the appropriate limit. Using Pantheon$+$/SH0ES Type~Ia supernovae, cosmic chronometers, DESI DR2 baryon acoustic oscillations, and Planck 2018 CMB distance priors, we constrain eight physically motivated sub-cases via Markov chain Monte Carlo and compare models through the Bayesian log-evidence. The entropy exponent is tightly bounded, $|m-1|\lesssim O(10^{-4})$ when the MHR coupling is fixed ($\gamma=1$), relaxing to $O(10^{-3})$ along the $m$-$\gamma$ degeneracy, excluding any macroscopically significant departure from standard horizon thermodynamics. Freeing the MHR coupling parameter or the entanglement amplitude raises the inferred Hubble constant to $h\simeq0.70$-$0.71$, reducing the CMB-SH0ES tension from ${\sim}4\sigma$ to ${\sim}1.2$-$2.6\sigma$, but no scenario fully resolves it within a flat universe. The Bayesian log-evidence nevertheless disfavors every extension relative to $\Lambda$CDM in all dataset combinations ($-16\lesssim\Delta\ln Z \lesssim-1$): the improved fits obtained when the SH0ES calibration is included reflect an absorption of the Hubble tension by the additional parameters rather than genuine evidence for modified horizon entropy.

We investigate the propagation of classical plane waves and surface plasmon-polariton modes within the framework of pseudo-electrodynamics (PED) supplemented by a non-local Chern-Simons (CS) topological term. Starting from the dimensionally reduced action, we derive the decoupled second-order wave equations for the electromagnetic field, and for the gauge-potential. In vacuum, we show that the topological CS parameter works as a dynamical mass generator, modifying the strict transversality of plane waves, and introducing a distinct energy gap in the dispersion relation. Considering a planar conducting medium that satisfies the Ohm law, the topological mass induces a novel hybridization mechanism between the Transverse Electric (TE), and Transverse Magnetic (TM) modes, a feature entirely absent in the conventional planar plasmonics. We analyze the asymptotic limits of this system, obtaining the exact real solutions in the lossless reactive Drude regime, and deriving the complex refractive index through a quasi-local approximation in the dissipative regime.

We analyze the vacuum dynamics of Gravity from Entropy, including its algebraically constrained $G$-field formulation. Evaluating the curvature traces over zero-, one-, and two-form sectors, we show that the complete Minkowski Hessian is exactly that of the quadratic-gravity action $A R+B R_{\mu\nu}R^{\mu\nu}$, with $A=3\beta/\ell_{\rm P}^{4}$ and $B=5\beta^{2}/(2\ell_{\rm P}^{4})$. For diagonalizable curvature blocks, the same action reduces to a sum over eigenvalue logarithms and reproduces these coefficients exactly. A strict diagonal-curvature restriction on the perturbations is instead only a reduced subsector and excludes non-diagonalizable type-N wave curvatures. Linearizing the $G$-field equations and subsequently imposing the algebraic vacuum constraint reproduces the same reduced metric equation and covariant Minkowski Hessian. The spectrum contains the massless graviton, a scalar with $m_{0}^{2}=3/(5\beta)$, and an opposite-residue spin-2 branch with $m_{2}^{2}=-6/(5\beta)=-2m_{0}^{2}$. For the foundational choice $\beta>0$, conventional Einstein normalization therefore implies a tachyonic spin-2 instability. We also show that every four-dimensional Ricci-flat metric solves the local bulk equations through quadratic curvature order, while square-zero Ricci-flat pp-waves are exact local vacuum solutions of the analytic metric-only logarithmic branch. On the isolated massless transverse-traceless eigenspace, the quadratic translation current has the standard general-relativistic normalization.

A driven qubit exchanges energy with the propagating modes that drive it. When two spatially separated modes drive a single qubit with opposite amplitudes, their net action on the qubit cancels. Yet the qubit can still transfer power from one mode to the other through stimulated emission. The directionality originates from opposite stimulated emission powers into each line. We realize this situation with a superconducting transmon qubit coupled to two transmission lines and show that the direction of the power flow is set by the phase $\phi$ of the qubit superposition between its ground and excited states, rather than by any classical control parameter. From a time-resolved measurement of the output power in one line, we observe a transfer that varies as $\cos\phi$ and hence changes direction between $\phi=0$ and $\phi=\pi$. The directionality of the total power flow is limited by the phase independent contributions of the reflected drive and of spontaneous emission, which sets a routing efficiency that we measure as a function of the input power. For an equal superposition of ground and excited qubit states (maximal coherence), the efficiency reaches $63\%$, close to the bound of $69\%$ expected from the measured qubit coherence times.

Beam-induced backgrounds at high-luminosity $e^+e^-$ colliders, such as the FCC-ee, are dominated by incoherent pair creation (IPC), and require computationally expensive simulations with dedicated Monte Carlo (MC) event generators. Reliable detector and machine-detector interface studies necessitate event samples that are several orders of magnitude larger than what is practically attainable with existing MC. To alleviate this bottleneck, we present D$e^+e^-$ffusion, a denoising diffusion probabilistic model that operates as a permutation-equivariant, set-valued surrogate for fast IPC simulation. Trained on a small GuineaPig++ sample, D$e^+e^-$ffusion faithfully reproduces the marginal and joint kinematic, angular, and positional distributions of all three IPC production processes. In addition, we assess the fidelity at the detector level by propagating both Geant4 and D$e^+e^-$ffusion events through a Geant4 simulation of the CLD vertex detector and by training a transformer-based two-sample classifier; the classifier achieves an area under the ROC curve of $0.553 \pm 0.016$. The trained model generates events nearly four orders of magnitude faster than Geant4, paving the way for a fast-simulation surrogate for FCC-ee design studies.

This study investigates the consequences of the intrinsic deformation of the fissioning nuclear system near the outer saddle point on the shape evolution of the nucleus from saddle to scission and on the properties of the fission fragments. It is found that trajectories generally split into at least three classes, asymmetric, near-symmetric, and highly-asymmetric fission, that are roughly determined by the initial magnitude of the octupole moment, and each of which exhibits different scission dynamics and fragment properties. Near-symmetric modes result in a highly elongated neck at scission, leading to the neck rupture occurring when the proto-fragments are further apart than is the case for typical asymmetric fission, which in turn leads to a lower total kinetic energy and higher total excitation energy. The majority of this additional excitation energy goes into the heavy fission fragment, that develops a substantial quadrupole deformation. A similar trend is observed for the total kinetic energy of highly-asymmetric fission events, and the opposite trend for the excitation energy of the fission fragments as the majority of the additional excitation energy goes into the light fission fragment instead. The study also characterizes the neck rupture, including its effect on the emission of scission neutrons in near-symmetric fission.

How the dynamical regime of the observed system affects equation discovery has mainly been investigated through comparisons across systems. However, such comparisons vary both the equations and the dynamics, confounding the effect of the regime with the difficulty of recovering the equations symbolically. We separate the two by varying the forcing of Lorenz-84, moving its fully observed post-transient trajectories through fixed-point, periodic, and chaotic regimes while preserving the equations' functional form. Within each regime, we separately vary the amount of data, the noise, and prior knowledge of which terms the equations contain. We then measure how well two complementary approaches, sparse regression over a fixed library of candidate functions (SINDy) and an evolutionary search over symbolic expression trees (PySR), recover the true equations' terms and coefficients. We find that recovery depends on whether the sampled states distinguish combinations of candidate functions: equations remain poorly recovered from fixed-point data even when the candidate set contains only the true terms. We link the effect of the dynamics on both algorithms to one object: the moment matrix of the candidate functions under the invariant measure of the regime. Small eigenvalues mark weakly distinguishable combinations of candidate functions: we show that more data, less noise, and more prior knowledge can mitigate the resulting recovery difficulties, while a zero eigenvalue makes distinct equations indistinguishable on the visited states. Hence, a more precise prior needs less informative data, with consequences for data collection, method design, and evaluation.

We study the charging and work-extraction properties of a graphene-based excitonic quantum battery embedded in a driven-dissipative optical microcavity. The system consists of a pair of intervalley excitons in strained graphene, where one exciton acts as the charger and the other as the quantum battery, both coupled to a common cavity mode through a Tavis-Cummings interaction. By solving the open-system dynamics, we analyze the ergotropy as a measure of extractable work and investigate how coherent and incoherent pumping, cavity loss, and the microcavity parameter influence the charging process. Our results show that the battery exhibits a transient ergotropy peak followed by relaxation to a steady state, with the maximum extractable work strongly controlled by the light-matter coupling strength. The study reveals an optimal regime for efficient charging and demonstrates the role of cavity engineering in enhancing work storage in excitonic quantum batteries.

We introduce a framework for fermionic variational Monte Carlo in which a continuous normalizing flow refines a fixed antisymmetric base wavefunction. The flow is a permutation-equivariant neural ordinary differential equation (ODE), a smooth, topology-preserving map; equivariance preserves the antisymmetry of the base, so the flow can in principle improve any antisymmetric ansatz that can be sampled efficiently. The flow deforms the nodal surface of the base but cannot change its topology, so the base must supply the correct nodal topology. We use Slater and Jastrow-Slater bases in this work. Exact samples from the flow's Born distribution are obtained by pushing pre-cached base samples through the forward ODE, requiring no Markov chain Monte Carlo at training time. Base samples are generated offline and reused across batches and runs, enabling embarrassingly parallel training across multiple GPUs. We introduce three permutation-equivariant vector field architectures, Pairwise Deep Sets, FermiNet Vector Fields, and Pairwise Deep Sets Gradient, each balancing expressivity and computational cost differently. We further introduce an augmented dynamics formulation that co-evolves the derivatives required for the kinetic energy as ODE state variables, eliminating differentiation through the ODE trajectory and significantly reducing wall-clock time and memory. On harmonically trapped spinless electrons, the flow reaches ground-state energies below configuration interaction with single and double excitations, on par with a FermiNet baseline trained with the same optimizer. Training shows near-ideal strong scaling to 128 NVIDIA A100 GPUs on NERSC's Perlmutter for the largest systems tested, up to $N = 48$ particles in three dimensions.

A search is performed for a scalar resonance X decaying into a Standard Model Higgs boson H and an additional scalar S, each decaying into a bottom-antibottom-quark pair, giving a $b\bar{b}b\bar{b}$ final state. Two event topologies are considered, depending on whether the Higgs boson is reconstructed from a single large-radius jet or from a pair of small-radius jets. The analysis uses proton-proton collision data at $\sqrt{s} = 13$ TeV, collected by the ATLAS experiment at the Large Hadron Collider during Run 2, corresponding to an integrated luminosity of 126-136 fb$^{-1}$ depending on the topology and the associated triggers. The search covers masses of 300 GeV-6 TeV for X and 70 GeV-5 TeV for S. The dominant multijet and $t\bar{t}$ backgrounds are estimated with a hierarchical model using Gaussian processes and normalizing flows. No significant excess over the Standard Model background expectation is observed. Upper limits at 95% confidence level are set on the production cross-section times branching ratio, ranging from 0.7 fb to 2.6 pb.

Learned flight-dynamics models are often trained on short windows extracted from longer recordings. Randomly splitting these windows can place dependent samples from the same physical flight in both training and evaluation sets. We audit this issue using a fixed snapshot of the NanoBench Crazyflie 2.1 dataset. The experiment holds evaluation flights, rollout starts, training-window count, validation data, and optimization budget fixed. In the contaminated protocol, [LeakagePercent] percent of a recording-disjoint training set is replaced with windows from evaluation recordings, while both arms use the same clean validation set. We compare a world-coordinate delta multilayer perceptron with a relative-coordinate control across [NumSeeds] fresh training seeds and [NumEvalFlights] complete evaluation recordings. The primary endpoint is failure-aware position RMSE over 1-second rollouts, analyzed with paired crossed recording-by-seed inference. Contamination lowers apparent world-model error by 12.1 percent, from 0.299 m to 0.262 m, but the predeclared 95 percent confidence interval for contaminated minus disjoint error is -0.0735 to 0.0011 m. Because the interval crosses zero, the confirmatory result is negative. Secondary horizons and the relative-coordinate model show similar trends, but no coordinate-representation interaction is supported. Reliable leakage assessment therefore requires recording-level splits, failure-aware rollouts, replication across fresh seeds, and inference over both recordings and optimization seeds.

The physics of Wigner solids is characterized by an interplay of elasticity and long-range electrostatics, endowing crystal defects with properties distinct from those in charge-neutral crystals. Recent experiments observing lattice melting and Wigner-crystal-adjacent phases in two dimensions necessitate an examination of how defects affect the long-wavelength properties of such solids. Here, we use duality techniques to construct a comprehensive framework for studying the contribution of vacancies and interstitials, dislocations, and disclinations to the effective action of two-dimensional charged crystals. This allows for a systematic investigation of the interaction energies for the different combinations of defect pairs. We further study melting transitions due to defect proliferation, assessing and justifying some of the assumptions present in the literature. In the metallic Wigner crystal phase, characterized by a finite ground state density of vacancies, we find phonons with a dispersion relation that varies in an unusual way with the vacancy density. Consequently, we discuss how thermodynamic properties of such a vacancy Fermi liquid can be probed in measurements of the melting temperature and speed of sound. The field theory developed here can serve as a starting point in the study of anomalous Hall crystals and charge density waves with defects.

Solution-processed OLEDs offer a scalable route to large-area devices, but achieving competitive efficiency in multilayer stacks remains a challenge due to difficulties in hole injection as well as solvent orthogonality between layers. A hole injection layer (HIL) based on a blend of PEDOT:PSS and a perfluorinated ionomer (PFI) addresses both challenges simultaneously: surface segregation of PFI during film drying creates a high-work-function interface improving hole injection into high-ionisation potential host materials, while the insolubility of the blend in aromatic solvents prevents intermixing with subsequently deposited layers. Using this HIL with a solution-processed mCPCN:SpiroAC-TRZ emissive layer, sky-blue OLEDs with a peak external quantum efficiency (EQEmax) of 21.7%, an external quantum efficiency (EQE) of 20.2% at 100 cd m-2, a peak luminance of 29,000 cd m-2 and a full width at half maximum (FWHM) emission linewidth of 69 nm are demonstrated. The PFI-based HIL approach is extended to the photochemically stable TADF emitter 5TCzBN (EQEmax 18.4%, FWHM 73 nm) and to sensitized / hyperfluorescent OLEDs incorporating the multi-resonance TADF terminal emitters n-DABNA (EQEmax 22.8%, FWHM 26 nm) and the dendrimer TCzBN-BMes (EQEmax 20.4%, FWHM 29 nm). These results establish the PEDOT:PSS:PFI HIL as a broadly compatible platform for high-performance solution-processed TADF OLEDs.

We introduce a class of Laplace operators associated with quantum graphs in the operator-system framework. To this end, we investigate structural properties of quantum graphs related to the Schur product and transposition. Our main innovation is the identification of a specific inner product on the space of matrices with respect to which the projection onto the operator system underlying a quantum graph is orthogonal. This enables us to define a quantum analogue of the classical incidence operator and the associated Laplace operator. We compare this construction with a recently proposed alternative definition and examine the resulting Laplace operators for several families of quantum graphs. These results extend fundamental constructions from spectral graph theory to the operator-algebraic setting, providing a step toward a spectral theory of quantum graphs that generalizes classical graph-theoretic concepts while revealing new connections with quantum information theory and noncommutative geometry.

Iron-chromium-aluminium (FeCrAl) alloys are leading candidates for accident-tolerant fuel cladding in light-water reactors, where their superior high-temperature oxidation resistance promises to extend coping times during loss-of-coolant accidents. The in-reactor lifetime of cladding is ultimately governed by radiation-induced microstructural evolution of which point defect transport is the dominant mechanism, however, this remains poorly understood. Here, we use a species-resolved kinetic Monte Carlo (KMC) model for vacancy diffusion in FeCrAl, parameterised by linear surrogate models trained on a database of migration barriers generated through the Hop-Decorate workflow. By sampling compositions spanning the Fe-rich to Cr-rich range of the Fe-Cr-Al system, we map how the local chemical environment controls vacancy hopping and hence macroscopic diffusivity. We find that increasing the Cr content in the alloy progressively decreases global diffusivity of vacancies even though activation energies stay relatively constant. This implies that the higher the Fe content in the alloy, the faster vacancies diffuse, thereby increasing annihilation events with fast-moving interstitials, potentially reducing irradiation induced defects and increasing radiation tolerance. Conversely, we find that Cr-rich alloy compositions stand out with a markedly elevated activation energy and significantly slower diffusion, orders of magnitude lower at accident-relevant temperatures. This indicates suppressed vacancy mobility in Cr-rich $\alpha'$ phases which are known to form under irradiation.

Antennas transmit information wirelessly from one location to another via electromagnetic waves. Miniaturizing them, however, is challenging since the radiation efficiencies of all traditional antennas, based on the principles of classical electromagnetics, plummet when their dimensions are shrunk to tiny fractions of the radiated wavelength. Lately, a new generation of antennas whose operations are underpinned by non-classical principles have been demonstrated and they can overcome this limitation. This enables embedded applications that were hitherto inaccessible. In addition, beam steering, which normally requires a large phased array (multiple antenna elements each much larger than the wavelength), can now be accomplished with a single element much smaller than the wavelength. Some of these antennas also have stealth attributes for secure and covert communication, which makes this new genre a disruptive new technology.

We study entanglement entropy in Deep Inelastic Scattering (DIS) using the dipole formulation of the high-energy limit of QCD. We argue that a reduced density matrix arises in low $x$ DIS due to a trace over unobserved color degrees of freedom and we obtain entanglement entropy in terms of dipole multiplicities, directly from the von Neumann entropy. Dipole multiplicities are obtained from a solution to low $x$ evolution equations, which we solve numerically. Unlike previous studies, we take into account both transverse-size and azimuthal-angle dependence in the dipole evolution kernel. We study both the exact solution of the equation as well as its double leading-logarithmic approximation (DLLA). We find that for the same initial dipole size, the DLLA solution generates a larger entropy. Finally, we calculate the dipole multiplicities and entanglement entropy and compare our results to the Shannon entropy of hadron multiplicities, as measured by the H1 collaboration.

We compute the viscoelastic and thermal response of non-homogeneous hadronic condensates at finite baryon density representing crystals of baryonic tubes and layers. We describe them using analytic solutions of the Skyrme model in $3+1$ dimensions as ground states for a perturbative approach. At low enough temperatures, the lowest-energy excitations are described by a free massless scalar field theory in $1+1$ dimensions. We apply the Green-Kubo formulas to such excitations to obtain the elasticity tensor and other response coefficients. The analytic results of our computations are compared with available results on the nuclear pasta phase.

Online fandom communities influence public opinion toward movies, musicians, and sports teams. Using a corpus of game-referencing tweets, we measure variation in sentiment toward National Football League (NFL) teams driven by geography, game outcomes, and team performance for the 2011–2014 NFL seasons. We estimate a fandom radius for each team, identifying regions where engagement exceeds background levels of discussion. We find sentiment for both winning and losing teams is positive immediately prior to games, drops at kickoff, and rebounds slightly during halftime. After halftime however, the trajectories diverge: Sentiment for winning teams increases toward the end of the game, while sentiment for losing teams remains low, though both end up below their start of game levels. Finally, a comparison between sentiment and win percentage reveals a weak positive relationship, suggesting that while team success contributes to fandom happiness, other factors also influence how fans discuss the NFL on social media. Our work contributes to a growing body of computational social science research that quantifies the many aspects of modern fandom.

The multiscan method is widely used in femtosecond laser writing of waveguide systems to increase the refractive index contrast and to control the eigenmode shape. Here, we investigate multiscan writing with a constant effective writing speed and show that the displacement between adjacent scans provides an additional degree of freedom for controlling eigenmode confinement. By optimizing the multiscan parameters, the effective mode area can be reduced, enabling an up to eightfold increase in fabrication speed compared to conventional single-scan writing. We further demonstrate that careful tuning of the multiscan geometry substantially reduces the anisotropy of inter-waveguide coupling. These findings are applied to the fabrication of three-dimensional waveguide arrays operating at wavelengths of 808 nm and 1450 nm, where reduced coupling anisotropy is achieved. The proposed approach may be useful for three-dimensional waveguide arrays employed in topological photonics experiments, where low coupling anisotropy is desired.

The motion of liquids and soft matter is over-damped and `slow' when viscosity dominates. In this (low Reynolds-number) limit and when the system is isothermal, the equations of motion may be generated via Onsager's variational principle, which neglects inertia. This variational approach is immensely powerful, being used to obtain equations of motion for colloidal fluids, droplets on surfaces and much more. However, inertia can play a role, manifesting as vibrations and under-damped motion. Here we show how to extend this variational framework so that it remains valid for when damping/dissipation and inertia are both equally important.

The former CERN RD50 collaboration develops monolithic active pixel high voltage (HV) CMOS sensors for future colliders with the aim of high radiation tolerance, good time resolution, and high granularity pixel detectors. The most recent prototype, the RD50-MPW4, was produced by LFoundry in December 2023 using a 150 nm CMOS process. It features a matrix of 64x64 pixels with a 62 $\mu$m pitch and employs a column-drain readout architecture. Compared to its predecessor, it now has separate analog and digital power domains and a new biasing scheme with a guard ring structure that supports bias voltages over 600 V. This contribution will discuss the design and latest results of the MPW4, where tests with unirradiated samples showed more than 99.9% efficiency, 16 $\mu$m spatial resolution and 10 ns timing resolution. Efficiencies of over 99% were achieved for samples irradiated to fluences of $1 \times 10^{15}$ 1 MeV n$_{\mathrm{eq}}/\mathrm{cm}^2$. A 3D map of the charge collection efficiency from a measurement with two-photon absorption laser is presented that nicely outlines the depletion depth of this radiation hard, high granularity monolithic active pixel sensor.

Where does the Standard Model's internal structure come from? Treating $\mathbb{O}\oplus\mathbb{H}\oplus\mathbb{C}\oplus\mathbb{R}$ as a module for its own multiplication algebra enables a particular origin story for the Standard Model's pre-Higgs, $\mathfrak{g}_{SM}:=\mathfrak{su}(3)_{C} \oplus \mathfrak{su}(2)_{L} \oplus \mathfrak{u}(1)_{Y},$ and post-Higgs, $\mathfrak{g}_{LE}:=\mathfrak{su}(3)_{C} \oplus \mathfrak{u}(1)_{Q},$ symmetries. In this model, weak hypercharge and electric charge operators, $Y$ and $Q,$ take on a remarkably simple form: $\sum \frac{1}{n}\mathbb{I}_{n\times n}$. Upon the introduction of Cayley-Dickson imaginary units, this 15 $\mathbb{R}$ dimensional $\mathbb{O}\oplus\mathbb{H}\oplus\mathbb{C}\oplus\mathbb{R}$ embeds naturally as a vector space into several well-studied 16 $\mathbb{R}$ dimensional algebras, which we generically refer to as $\mathbb{V}.$ With this embedding, the Standard Model's internal symmetries may then be seen to arise in part from the sequence of nested inclusions: $\mathbb{R}\subset\mathbb{C}\subset\mathbb{H}\subset \mathbb{O}\subset\mathbb{V}.$ In the sedenionic case of $\mathbb{V}= \mathbb{S}$, the full sequence becomes a Cayley-Dickson tower. We define the notion of endomorphic models of particle physics, and connect $End_\mathbb{R}(\mathbb{V})\simeq Cl(0,8)$ to the earlier ideas of Bott Periodic Particle Physics. We comment on a possible connection between the existence of multiple complex structures and the baryon asymmetry problem. In closing, we identify an appearance in this model of the fully connected tree of division algebraic Hopf fibrations that starts at $S^{15},$ and simultaneously involves the four parallelizable spheres $S^7, S^3, S^1, S^0.$