Papers

The effective action at one-loop for the quantum electrodynamics (QED) in the presence of background vectors and tensors that break the Lorentz symmetry is calculated in this work. We highlight that just the Lorentz symmetry violation through the Dirac matrices in the fermionic sector is considered since investigations in others sectors of the extended QED has been explored in recent papers. Using the proper time method, we show that some background vectors and tensors do not contribute to the effective action at one-loop and in the linear approximation. Thereby, only two background tensors contribute to the effective action at one-loop for small components of these tensors, and that a new combination of cubic and quartic non-linear electrodynamics emerge in the weak field regime.

Hard carbons are promising anodes for sodium-ion energy storage, yet the relationship between their heterogeneous microstructure and sodium transport remains poorly understood. Here, we combine machine-learning-generated hard-carbon structures with molecular dynamics simulations of explicit 1 M NaPF6 in ethylene carbonate/dimethyl carbonate electrolyte to investigate sodium storage and transport across carbon structures with densities from 0.5 to 2.0 g cm-3. Increasing carbon density produces less accessible pore networks and greater graphitic local ordering, allowing the influence of microstructure on electrochemical response and Na+ transport to be examined systematically. Sodium uptake increases with applied potential but decreases strongly with carbon density, while electrode charging persists even in the densest structure, where Na+ uptake remains very small. Coordination analysis shows increasing interaction with the carbon framework under applied potential, while Na+ retains a partially solvated environment. Three-dimensional trajectory analysis reveals heterogeneous, predominantly tortuous transport pathways, with the more open HC-C1 structure supporting broader penetration and greater sustained displacement. Maximum penetration depth and retained displacement are not equivalent: ions can transiently reach deep regions of denser carbon structures before returning towards the electrolyte interface. Potential-of-mean-force analysis further shows that deep penetration occurs across a range of projected free-energy changes and cannot be described by a single energetic criterion. These results show that Na+ storage and transport are governed by the interplay between electrostatic driving force, electrolyte solvation, pore accessibility and confinement, highlighting carbon microstructure as a key determinant of sustained ionic penetration.

We construct and classify $Z_2$ quantum spin liquids (QSLs) of fermionic partons on the dipolar-octupolar (DO) pyrochlore lattice. The DO pseudospin shares the space-group and time-reversal algebra of the effective spin-1/2 Kramers doublet, its projective symmetry group (PSG) yields the same 48 symmetric $Z_2$ classes as the generic fermionic classification. We show, the distinct DO symmetry action, encoded in a set of sublattice-independent operators, selects a physically different set of symmetry-allowed mean-field channels, so that the resulting ansatze, spinon spectra, and observables differ from both the effective spin-1/2 case and the bosonic DO classification. Decomposing the anisotropic XYZ exchange model into all symmetric singlet and triplet hopping and pairing channels and minimizing the mean-field energy self-consistently, we obtain phase diagrams in the ($\tilde{J_x}, \tilde{J_z}$) plane in which only a few $Z_2$ states, several supporting gapless or flat-band spinon spectra, are stabilized. For these states we compute the spinon band structures, the low-temperature specific heat, and the dynamical spin structure factor, and we argue that the power-law specific-heat exponent is a diagnostic of the spinon nodal structure. A near-linear-in-temperature specific heat together with broad continua in the structure factor gives a fermionic-parton account of the gapless, fractionalized thermodynamics reported in DO materials such as $Nd_2ScNbO_7$, complementing the bosonic quantum-spin-ice picture of the Ce-based compounds. The work extends the fermionic-parton classification of DO pyrochlore QSLs beyond the $U(1)$ sector, where $Z_2$ topological order is realized equally naturally by fermionic and bosonic spinons.

The Island Formula for Quantum Extremal Surfaces of large AdS black holes, which are made to evaporate by coupling the CFT of the AdS/CFT correspondence to an external system, demonstrates that the space time picture can reproduce the quantum mechanically required Page curve of the CFT/bath system if a region in the interior of the black hole has become entangled with the external radiation by the Page time. In an effective quantum field theory (EFT) description in “nice slice" coordinates, this appears to imply paradoxical entanglement between degrees of freedom that have been causally disconnected since long before the Page time. We will give two arguments that all of the quantum information in the island is in fact concentrated in a tiny space-like portion of the island very close to the black hole horizon at the Page time. The first applies the covariant entropy bound\cite{fsb} (CEB) to the causal diamonds of geodesics originating on the space-like region that becomes the island, but on a time slice just before the Page time. All points on the island except those in a stretched horizon region very close to the horizon have entropy bounds that are tiny fractions of the black hole entropy. The second argument uses standard quantum statistical mechanics combined with the tensor network renormalization group regularization of CFT to argue that the wave function of a typical pure state in the microcanonical evaporating black hole always has most of its probability concentrated in a small range of wavelengths corresponding to a small range of radii in the dual tensor network/AdS slice.

Flutter onset is determined by the sign of the aerodynamic work on the structure, but cycle-integrated work does not reveal where this energy transfer originates. We perform direct numerical simulations of incompressible flow over an aspect-ratio-two NACA 0015 wing pitching at $Re=1000$ and use lobe-resolved force-moment partitioning to identify the vortical contributions to aeroelastic power. The net energy transfer changes sign near $U^*=4.25$. Across this transition, the upper leading-edge contribution changes from damping at $U^*=2$ to excitation near onset and becomes the largest positive contribution at $U^*=6$. Near the stability boundary, positive leading-edge work is nearly balanced by negative trailing-edge work. This change is accompanied by a reorganization of the leading-edge pressure footprint and a reduction in the phase difference between aerodynamic moment and pitch rate, linking flutter onset to the timing of the leading-edge vortex system. A single slowly growing-amplitude simulation recovers the finite-amplitude energy boundary, while a free-pitching calculation confirms the predicted instability. As the motion approaches its limit cycle, the energy pathways redistribute, and a response-frequency-matched forced calculation reproduces the large-amplitude energy budget. These results distinguish the mechanism that triggers flutter from that which saturates the response and identify the leading edge as a natural target for flutter suppression.

We reveal that a chiral cavity distinguishes the resonant and antiresonant interactions between a two-dimensional electron gas and the cavity vacuum. For co-rotating helicities, the modes anticross, exhibiting vacuum Rabi splitting, and retain a bare vacuum ground state. For counter-rotating helicities, the modes cross, acquiring vacuum-mediated energy shifts and a two-mode squeezed ground state. We trace the origin of these observations to the SU(2) and SU(1,1) symmetries of the respective Hamiltonians and present their spectroscopic signatures in chiral photonic crystal cavities. We further predict that cavity chirality produces a handedness-dependent correction to Hall resistivity at finite polariton broadening, while such a correction is not present in an achiral cavity. For the longitudinal resistivity, we find an asymmetric response of the Shubnikov–de Haas oscillations for the different helicities. Finally, we present an experimentally accessible route for detecting the squeezed ground state through current fluctuations. Parameters based on a recently demonstrated terahertz chiral cavity place these effects within experimental reach.

Streaming GPU solvers for entropic optimal transport (EOT), such as FlashSinkhorn, avoid storing the dense kernel but still evaluate all $n\times m$ point pairs in every Sinkhorn iteration. We present FlashSinkhorn~2 (FS2), a solver for squared-Euclidean cost on low-dimensional point clouds that solves large discrete EOT problems to a prescribed marginal residual on a single GPU by coupling two stages. A coarse stage solves on cell centroids, lifts the potentials to every point and, when a sampled marginal check rejects the lift, continues on the centroids, replacing most point-level updates. A block-sparse fine stage then removes the centroid error that coarse updates cannot. Its Morton-ordered blocks support screening and fused tensor-core execution, and a threshold set by the block masses bounds each omitted tile's contribution to every row and column. On synthetic benchmarks, FS2 reaches the target residual on all 32 problems and GeomLoss multiscale on 10. On one A100, FS2 solves discrete EOT between two $1.34\times10^8$-particle measures from a cosmological $N$-body simulation, at an entropic blur equal to the mean interparticle distance, to an all-particle marginal residual below 0.01 in under 2.5 hours. To our knowledge, it is the largest discrete EOT problem solved to this accuracy within hours. For reproducibility, we release an open-source implementation at https://github.com/ot-triton-lab/flash-sinkhorn

We apply the stochastic all-mode technique to general coarse-graining schemes of the tensor renormalization group (TRG) approach. The technique possesses a notable characteristic of being entirely free from systematic errors which can potentially arise in the coarse-graining step, while it has statistical errors caused by random noise. The key element in our generalization is employing a method called squeezer, and the all-mode technique can be used when it is constructed. Since many TRG methods can be described in terms of the squeezers, our approach can be applicable in all such cases. In this work, we demonstrate the new method with higher-order TRG in the two- and three-dimensional Ising model.

We propose Q(q,d), a family of q-ary non-CSS qudit stabilizer codes with prime power q and dimension d >= 2, constructed from Singer difference sets and non-degenerate quadrics in PG(d,q). The parity check H = (A | M_Q A) couples the Singer-circulant incidence matrix A with the quadric circulant M_Q, and a Cancellation Lemma uses the identity (k - lambda) = q^{d-1} = 0 mod p to make H symplectic-isotropic over F_q. Five structural theorems carry the novelty: a cross-correlation modular-constancy identity nu = 1 mod q at q odd, d >= 3, with a two-value pattern that proves a 2-torsion distance ceiling; a CRT zero-count identity; an explicit Clifford bridge identifying Q(q,2) as a graph-state encoding of the trivial Singer CSS code, with the 2021 low-density-spreading (LDS) sign-flip pattern realised by a symmetric circulant; a paired column-rigidity equality d_min = R_P + 1; and a lower bound d_min(Q(7,2)) >= 8 from an exhaustive Singer-Frobenius search. A Hamada-Smith specialisation yields the closed-form logical dimension k(p,d) = theta_d(p) - C(p+d-1, d) - 1, and the flagship Q(p,2) = [[p^2 + p + 1, p(p+1)/2, d_min]]_p attains asymptotic rate one-half. We conjecture d_min(Q(p,2)) = p + 1 for odd primes, proven at p = 5 and lower-bounded to >= 8 at p = 7. Instances include Q(3,2) = [[13,6,3]]_3, Q(5,2) = [[31,15,6]]_5, Q(7,2) = [[57,28, d>=8]]_7, and Q(3,4) = [[121,105,3]]_3. Monte-Carlo over 1.5 x 10^6 trials shows Q(5,2) achieves a 70-fold per-logical-qudit improvement over Steane [[7,1,3]]_2 at depolarising rate 10^-3 with zero silent logical errors. A textbook bounded-distance decoder is used; Berlekamp-Massey-style cyclic decoding is left as the natural sequel.

Here, we explore magnetic field amplification by the small-scale dynamo (SSD) during the formation of the first stars and galaxies. Gravitational collapse continuously modifies turbulent velocities and length scales, making the SSD fundamentally different from a dynamo operating in stationary turbulence. In arXiv:2503.19131, we developed a supercomoving formulation of turbulent dynamos and showed that the increasing dynamo growth rate during collapse leads to super-exponential (SE) magnetic field amplification in the kinematic stage. Here, we show that collapse also accelerates the slower nonlinear stage, allowing magnetic energy to reach progressively larger scales. We apply this framework to first-star and first-galaxy formation and find that the impact of collapse depends strongly on the dynamo efficiency. If the dynamo is sufficiently fast, the field reaches saturation before substantial collapse occurs, leaving little room for further acceleration. At the opposite extreme, if the dynamo is too slow, dynamo amplification remains weak and flux freezing dominates. Between these limits, collapse can substantially accelerate the dynamo, with speed-ups of >10 in the parameter space explored, enabling dynamically significant fields to develop within the available collapse time. Nonlinear scale-by-scale saturation further produces fields correlated on a non-negligible fraction of the system. We provide estimates and scaling relations for the final field strength and correlation scale and their dependence on halo, turbulence, dynamo, and collapse parameters. The earlier emergence of dynamically important fields can affect fragmentation, angular-momentum transport, and the subsequent evolution of the first stars and galaxies.

Ambient-temperature coexistence of ferroelectricity, photoconductivity, and ionic transport in ultra-thin van der Waals (vdW) compound CuCrP2S6 (CCPS) offers significant potential for multifunctional electronic, photonic, and neuromorphic applications. However, ferroelectricity and ionic transport can become antagonistic when sharing a common atomic origin, like the copper ions in CCPS. We address this fundamental dichotomy by systematically investigating the thickness-dependent evolution of ferroelectricity, ionic migration, and memristive behavior in CCPS diodes via electrostatic and photo-assisted interfacial band tuning. Using piezoresponse, Kelvin probe, and conductive atomic force microscopy, alongside photoexcited transport measurements, we identify distinct thickness regimes. CCPS flakes thinner than ~ 40 nm exhibit robust, reversible ferroelectric (FE) switching. Conversely, thicker samples display suppressed switchable polarization, with electrical conduction dominated by Cu+ migration, filamentary memristive switching, and rectification reversal. Optical illumination further enhances ionic mobility via photogenerated carriers, driving photo-assisted ionic transport in non-FE flakes and a coupled photoferroionic response in FE flakes. These findings clarify how ferroelectricity fundamentally alters ionic transport dynamics in vdW ferroionic systems.

AN~Col is a shell Be star that has shown transient spectral features caused by a hot, evolved companion on a months-long orbit. If confirmed, this would place it among the growing category of post-mass-transfer spun-up Be + stripped subdwarf OB-type (sdOB) binaries. Characterizing the binary orbit enables obtaining dynamical masses, to provide a rare anchor for models of binary evolution and mass transfer. We present a full 3-dimensional orbital solution, dynamical masses, and dynamical parallax, for the newly discovered Be + sdOB binary AN~Col. As a prerequisite to obtain a reliable orbital solution, we need to characterize the disk-wide density oscillation cycle that gives rise to the dominant spectroscopic cycles in order to separate the weaker periodic orbital variations. We use near-IR interferometry time series from GRAVITY to confirm the companion and to map the relative astrometric orbit. With the knowledge of the orbital period, we identify spectral lines that trace the orbit of each of the two stellar components and we measure their radial velocities to obtain a double-lined spectroscopic orbit. Combining interferometry and spectroscopy, we derive the full 3-dimensional orbital solution. The disk has completed three full oscillation cycles since 2010, with a cycle length of ~5.1 yr. The ~87.7-day orbit is compatible with edge-on orientation, but the lack of eclipses in TESS light curves limits the orbital inclination to 88.4$^{\circ}$ or less. The resulting masses are $M_{\rm Be} = 8.39\pm0.67$ Msun and $M_{\rm sdOB} = 0.81\pm0.22$ Msun. As in other Be + sdOB binaries, the estimated efficiency of the past mass transfer is unexpectedly high. Detection of a weak \spec{He}{ii}{4686} absorption and other \ion{He}{i} lines from the companion indicates that its effective temperature is close to 30 kK, and that it is a slow rotator. [abstract continues but no space left...]

Dissipative dynamics can stabilize a quantum target without providing a reliable sequence of finite control operations. We derive checkable conditions for implementing such stabilization with imperfect controls, with bounds on convergence, errors during operations, and physical cost. The analysis includes pulses, idle intervals, and all simultaneously acting background dynamics. Using a common Lyapunov measure of deviation from the target, we require a contraction bound that remains uniformly below one over the prescribed uncertainty set after accounting for implementation errors. If all allowed paths preserve the target subspace throughout each operation, repeated cycles converge to that subspace from every initial state, even when errors vary between cycles. Comparison with these certified target-preserving paths gives an explicit long-time error bound under bounded leakage. Two single-qubit counterexamples show why a stabilizing average or a stabilizing generator obtained by unitary conjugation does not ensure these path conditions. The certification approach also supports a finite-library search. For a specified four-level cascade model with finite pulses, calibration and timing errors, dephasing, and bounded pumping, this search yields a sequence with an explicit preparation-time bound. For every initial state, it guarantees trace distance at most $0.1$ from the target at the end of preparation and throughout subsequent cycles.

This work establishes finite-time blow-up for the completely integrable defocusing Ablowitz-Ladik equation on both infinite and finite lattices. We first establish local well-posedness for arbitrary initial data in the space $\ell^\infty$ of uniformly bounded sequences, with no decay assumptions and under general boundary conditions. We then show that the unit circle acts as a separatrix for the lattice dynamics: sites with an initial modulus inside, on, or outside the unit circle maintain their modulus within their respective region for as long as the solution exists. As a consequence, initial data in the closure of the $\ell^\infty$ unit ball generate global-in-time solutions. On the other hand, the unit circle separatrix opens up the possibility for finite-time blow-up, which is restricted to sites with initial modulus outside the unit circle. We establish this scenario by constructing a class of initial data whose corresponding solutions are singular, with explicitly given exact blow-up times. We also construct solutions emanating from initial data with an arbitrarily large single-site excitation outside the unit circle that exist globally in time, a behavior driven by the convergence of the corresponding modulus to the unit circle equilibrium. In the presence of such solutions, along with other important classes of analytical, global-in-time solutions that remain outside the closed $\ell^\infty$ unit ball for all times, we examine the fundamental question of the dominant dynamics for general initial data outside the closed unit ball. By utilizing the constructed class of singular solutions as subsolutions for the general problem, we prove that the dynamics for the completely integrable defocusing Ablowitz-Ladik lattice is dominated by finite-time blow-up. We conclude with numerical studies of illustrative examples of general initial data

We establish lower bounds on the number of resonances for three-dimensional semiclassical Dirac operators with mass-type potentials. For a pair $\Dl_j=\Dl_0+\mbf{\beta}v_j$, $j=1,2$, satisfying the exterior analyticity, decay and non-degeneracy assumptions of the paper, we associate a relative distribution $\mu$ to the corresponding mass functions. We prove that if $E_0>1$ is a boundary point of $\supp\mu$, then every complex neighbourhood of $E_0$, and likewise of $-E_0$, contains in total at least $C\hbar^{-3}$ resonances of the two operators, counted with multiplicity. The proof transfers an analytic wave-front singularity of $\mu$ to the relative classical density of states and combines this with Khochman's local trace formula and a relative semiclassical trace formula. As a consequence, if $v$ is a single bounded mass-type potential, analytic with power decay in an exterior sector, with $\inf(1+v)>0$ and $\sup v>0$, then $\Dl=\Dl_0+\mbf{\beta}v$ has at least $C\hbar^{-3}$ resonances in every complex neighbourhood of $E_0=1+\sup v$ and of $-E_0$, for all sufficiently small $\hbar$. The exponent agrees with Khochman's upper bound, the two resonance families are related by spectral symmetry, and $E_0$ is necessarily a trapping energy. We also prove the relative semiclassical trace formula needed in the argument for general Hermitian matrix-valued perturbations.

We construct spectral-parameter solutions of the quantum Yang–Baxter equation from the associativity condition of the universal symmetric $2$-algebraic two-valued group, whose multiplication law depends on four coefficients $k_2,k_4,k_6,k_8$ subject to the single relation $4k_8-k_4^2+k_2k_6=0$ – which coincides with the three-dimensional WDVV equation for Dubrovin's normalised potential. Every three-dimensional Frobenius manifold with a cyclic vector field carries such a spectral two-valued group, whose finite branch points are the eigenvalues of the multiplication operator. For an arbitrary unital algebra we show that a two-parameter spectral $R$-operator built from multiplication and unit has Yang–Baxter defect proportional to an explicit tensor built from the associator; for tangent Frobenius algebras this yields a regular, unitary $9\times9$ $R$-matrix satisfying the quantum Yang–Baxter equation exactly at WDVV points, with spectral parameter the Abel coordinate of a bielliptic curve whose elliptic quotient is the spectral curve, together with an associated integrable chain. The $A_3$ Frobenius manifold is worked out explicitly.

Selective advantage leads to the proliferation of a species into an ecosystem. On the other hand, self-propulsion can lead to dynamic clustering of individuals. To analyze the intricate effects produced by such competing processes, we introduce a minimal model for a proliferating active population, where run-and-tumble migration is combined with a stochastic birth-death process. Beginning with the microscopic dynamics of the particles, we derive the corresponding hydrodynamic equations and validate them through numerical simulations. We demonstrate that the inclusion of activity leads to the emergence of novel morphological patterns, which are sensitive to the specific rules governing migration. Furthermore, we show that activity significantly alters the characteristics of invasion waves, increasing their propagation speed. However, beyond a threshold, excessive activity disrupts the wave-like nature of the invasion process. We also extend our study to two dimensions and analyze the instabilities that lead to pattern formation in such systems.

We extend the modularity-based approach of arXiv:2509.02226 for the holographic thermal propagator to the physically relevant case of nonzero energy $\omega$. Via the AGT correspondence, the problem is mapped to $\mathcal{N}=2$ $SU(2)$ gauge theory with $N_f=4$ hypermultiplets. Turning on $\omega$ activates all four hypermultiplet masses, so that the full $SO(8)$ flavor symmetry constrains the low-temperature expansion, rather than the subgroup left unbroken at $\omega=0$. As a result, the building blocks of the expansion are no longer just Eisenstein series but also Jacobi theta functions. We use this fact, together with the Molien series of the resulting invariant ring and the modular anomaly equation, to fix the low-temperature expansion coefficients order by order, matching only a finite number of terms in the Zamolodchikov's $q$-recursion at each order. We obtain the low-temperature expansion of the propagator and find agreement with the result of a completely different method, the near-boundary expansion of the bulk wave equation.

The growth in seismic acquisition techniques has led to large-scale surveys, making traditional manual dispersion analysis logistically and computationally prohibitive. While deep learning techniques can offer an automated alternative, standard convolutional neural networks (CNNs) often fail to account for the non-uniqueness of the inverse problem and can produce geologically unrealistic, smooth velocity models. To address these challenges, we propose a physics-guided multi-modal variational autoencoder (PG-VAE) for scalable near-surface characterization. Our framework introduces a multi-stream fusion strategy that maps independent latent features from both raw shot gathers and spectral-dispersion images by leveraging the physics of Rayleigh-wave dispersion. We implement a specialized decoder architecture with learned transposed convolutions and residual refinement to enforce a structural bias towards layered earth models. Physics guidance is incorporated via a differentiable surrogate network that serves as a forward-consistency regularizer, penalizing predictions that violate the physics of Rayleigh-wave dispersion. The network is trained on diverse synthetic data generated via elastic modeling, and then validated on unseen synthetic data, and subsequently evaluated on an ultra-high-density field dataset from the Devine test site in Texas. We also employ gradient-weighted class activation mapping (Grad-CAM) to examine the input features contributing to the network predictions. The proposed method could serve as a scalable tool for near-surface characterization and as an initial model-building tool for high-resolution elastic full-waveform inversion.

In this reflection, I want to look back over more than thirty years, from 1978 to 2008, of my professional and personal relationship with Mannque Rho. I will briefly describe some of the original ideas that emerged from our collaboration: the Little Bag, the Cheshire Cat principle, and Skyrmion matter. I do not intend to be exhaustive, neither in content nor in references, which can be found in our published works. Instead, I want to retrace the path we took together through physics, accompanied by many good friends.

The neutrino flavor composition in supernovae and neutron star mergers is shaped by flavor instabilities, which are commonly classified into three types: slow (SFI), fast (FFI), and collisional (CFI). The focus here is on mixed-type instabilities combining attributes of the standard varieties. We examine instability growth rates in two-dimensional parameter spaces (“phase diagrams”) whose axes correspond to instabilities of pure type. We find critical curves connecting the pure-type instability onset points. We also exhibit qualitative trends in the growth-rate spectra $\gamma_{\bm{k}}$, emphasizing the occurrence of crossovers and phase transitions in the fastest-growing Fourier mode $k_{\textrm{max}}$ and drawing attention to the distinction between spatial-mean ($\bm{k} = 0$) and flavor-wave ($\bm{k} \neq 0$) instabilities. Our paper is a step toward understanding flavor instabilities as they actually occur in nature rather than in idealized limits.

Observations of Faraday rotation in the lensing galaxy of CLASS B1152+199 at z = 0.439 suggest that efficient dynamo mechanisms had already amplified galactic magnetic fields by this epoch. We assess the reliability of this method for deriving magnetic field strengths and the likelihood of observing similarly large Faraday rotation differences. We select 64 star-forming disk galaxies from the TNG50 cosmological magnetohydrodynamical simulation, matched to CLASS B1152+199 in mass and redshift, and forward model them using polarized radiative transfer with POLARIS and subsequent RM synthesis. TNG50 predicts characteristic large-scale field strengths of B$_0$ = 1.9-15.6 $\mu$G for individual galaxies, while the combined sample yields B$_0$ = 10.3 $\mu$G. Field strengths B$_{obs}$ inferred from the synthetic observations generally recover B$_0$ within a factor of three. B$_{obs}$ depends only weakly on the assumed magnetic field geometry, whereas galaxy inclination and beam depolarization have stronger effects. The differential rotation measure recovered from RM synthesis remains correlated with the directly integrated value, although beam depolarization systematically reduces its magnitude. Only 1.41% of directly integrated sightline pairs reproduce the observed $\Delta$RM = 1040 $\pm$ 60 rad m$^{-2}$ of CLASS B1152+199, increasing to 3.16% for sightlines at galactocentric distances comparable to the observed 2.6 and 6.5 kpc. Differential Faraday rotation of gravitationally lensed sources therefore provides a robust probe of large-scale magnetic fields, while the large $\Delta$RM of CLASS B1152+199 is relatively rare among the considered TNG50 analog galaxies.

Prompt-photon production with recoiling QCD radiation is crucial for new-physics searches, determinations of parton distribution and fragmentation functions, and jet-quenching studies in heavy-ion collisions. We present the first fully differential NNLO QCD predictions for photon-associated identified-hadron production at the LHC. We compare predictions obtained with different fragmentation function (FF) sets to ALICE and ATLAS data at $\sqrt{s}=5.02\,{\rm TeV}$. Our calculation provides an important theoretical ingredient for FF global fits and offers a precision proton–proton baseline for photon-tagged heavy-ion studies.

In the temperature interval $T\sim 50 - 100 K$, the rate of electron-electron collisions in graphene devices may exceed the momentum relaxation rate due to disorder and electron-phonon scattering. In this regime, the motion of the electron liquid may be described by the hydrodynamic equations. In the hydrodynamic approximation, at the charge neutrality point the electric current is decoupled from the hydrodynamic flow, and the conductivity of the system is equal to the intrinsic conductivity of the electron liquid, $\sigma_0$. It was recently shown that the coupling of charge transport and hydrodynamic flow induced by the thermal fluctuations enhances the macroscopic conductivity of the system and results in very strong positive magnetoresistance (MR) at relatively weak fields. Here we develop a quantitative theory of the fluctuation mechanism of MR at charge neutrality and obtain analytic expressions for MR in graphene Hall bars. The functional dependence of MR on the magnetic field $H$ is sensitive to the Hall bar geometry and orientation relative to the current. We also account for the effect of momentum relaxation on MR.

Quantum read only memory (QROM) is a substantial source of non-Clifford cost in fault-tolerant quantum algorithms. Borrowing dirty qubits can reduce this cost, provided their unknown initial states are restored. We consider the practically relevant qubit-constrained regime, where limited workspace restricts the table-block size and table loading dominates the cost. For $N$ entries of $b$ bits and approximately $b\lambda$ dirty qubits, SelectSwap has leading Toffoli count $2N/\lambda$. Recent work using sequential bit packets reduces this to $(1+1/b)N/\lambda$. In this work we introduce a dense encoding construction of QROM, where two bits of classical information are stored in each dirty qubit instead of one by utilizing both the $Z$ and $X$ bases. On its own, dense encoding provides a $2\times$ improvement over SelectSwap by reducing the leading Toffoli count to $N/\lambda$. Combining it with sequential bit packets gives $\tfrac12(1+1/b)N/\lambda$, a further halving of the sequential construction's leading cost, and an approximately $4\times$ improvement over SelectSwap in the large-$N$ limit for practical values of $b$.

We present an elementary recursive construction of Hermitian projectors on multi-quark ${\rm SU}(N)$ color states, based on the characterization of these states by their quadratic Casimir, and using the birdtrack pictorial technique.

Complete event generation on hardware accelerators such as GPUs requires vectorising the algorithms of components such as parton showers and hadronisation. To this end, I implemented a simplified cluster hadronisation and hadronic decay model in the GPU parton shower program GAPS, with one thread per event and each stage of the algorithm as a separate kernel. I compared simulation results for $e^+e^- \to \text{hadrons}$ at the $Z$ pole with the Herwig event generator and with ALEPH and L3 data, and measured execution times on an NVIDIA V100 GPU. The results agree well with Herwig, and GAPS generates one million hadron-level events (NLO hard process, shower, hadronisation and decays) in about four seconds on this GPU.

Extreme-mass-ratio inspirals are key gravitational-wave sources for testing strong gravity and the environments of massive black holes. While orbital motion in Kerr black hole spacetimes is integrable, realistic black holes may be surrounded by environments that break integrability. We investigate conservative orbital dynamics around rotating black holes surrounded by scalar clouds using fully nonlinear numerical solutions and an analytical post-Newtonian model. Poincaré sections and rotation curves reveal finite-width resonant islands, providing evidence for non-integrability even when the cloud carries only a small fraction of the black-hole mass. We show that the post-Newtonian description reproduces the dominant resonance and its island width for weak clouds, but underestimates the width in the configurations with stronger, more compact clouds examined here. Moreover, we find that for a scalar cloud as massive as the black hole, the phase space exhibits wider resonant islands as well as scattered layers indicative of chaotic motion. Together with earlier work, these results show that environmental effects can generically break the integrability of geodesic motion, motivating further study of resonance crossings and their gravitational-wave signatures once radiation reaction is included.

We develop a finite element method (FEM) for partial differential equation (PDE) solver based on the entanglement-basis representation introduced in our companion work. By lifting non-linear finite-element equations into an augmented coefficient space, the governing PDE together with boundary, initial, and inter-element constraints can be expressed through a unified quadratic residual minimization. Although this augmented space grows exponentially with the number of elements, its tensor-product structure allows it to be represented efficiently using tensor networks. Using the matrix product state (MPS) as a concrete example, we show that density matrix renormalization group (DMRG) sweeps enable element-by-element optimization without explicitly constructing the full augmented space. For bounded bond dimension, the resulting computational cost scales polynomially with the number of finite elements. We extend the framework to time-dependent problems through implicit temporal discretization and demonstrate convergence under both mesh and polynomial refinement using diffusion equations.

Different theories of dark matter predict different populations and morphologies of galactic subhaloes below about $10^8M_{\odot}$. The planned angular resolution and optical stability of the Habitable Worlds Observatory (HWO) should enable it to detect subtle subhalo perturbations in strongly lensed galaxy images. We simulate 2000-second exposures with its High Resolution Imager (HRI) under the fiducial Exploratory Analytic Case 1 (EAC1) design, assuming known source structure and omitting lens-galaxy light. Pre-selecting the top 50 of 965 lenses (5.2%) using only arc signal-to-noise and relative gradient power lowers the median mass threshold for 10% aperture coverage roughly tenfold relative to the full ensemble. The top 12 (1.2%) reach a median of $6.6\times10^7M_{\odot}$ for the same coverage. At their most sensitive positions, the top 50 and top 12 reach median thresholds of $3\times10^7M_{\odot}$ and $1.5\times10^7M_{\odot}$, respectively. Non-linear fits support the Fisher forecasts at the tested masses and positions. For these 12 lenses, increasing the physical wavefront error from 35 to 65 nm RMS raises the median thresholds by only 0.1 dex when the point spread function (PSF) is modelled correctly. Deliberately mismodelling the 35-nm reference PSF removes detectable positions, although false detections remain rare. Under our illustrative retention criteria, loss of sensitive area sets a median tolerated wavefront mismatch of 5 nm RMS (range 2–10 nm). Selective HWO follow-up of lenses discovered by Euclid or Roman could therefore transform our understanding of the nature of dark matter, provided that the PSF is characterized accurately enough to preserve this sensitivity.