Papers

Solar active regions are the source of virtually all significant space weather events, therefore the relationship between their observable properties and flare production is important to characterize. The flare productivity of solar active regions is analyzed across solar cycles 23–25 as a function of magnetic complexity, sunspot area, and solar-cycle phase. Additionally, the power-law index of the peak flux frequency distribution is estimated. The GOES soft X-ray event reports matched with daily Solar Region Summaries (SRS) are used to create a robust active region catalog. This catalog is supplemented with the 50-year HEK flare catalog and the newly released STIX flare catalog from Solar Orbiter to estimate the power-law index. Magnetically complex active regions ($\beta\gamma$, $\beta\delta$, $\beta\gamma\delta$) produce the majority of M- and X-class flares while comprising only $\sim$13% of all daily active-region observations, showing that larger flares disproportionately occur in larger area sunspots. All three catalogs can be represented with a consistent power-law index of $\alpha = 2.02 \pm 0.01$ for the peak flux frequency distribution. However, a class-by-class analysis of the C/X and M/X flare ratios reveals that the distribution steepens significantly towards higher energies. Fitting this steepening as a lognormal tail and extrapolating two decades beyond the X-class threshold predicts a recurrence time of $370^{+292}_{-159}$~yr for an X100-class (`Carrington-type') superflare, compared to only $\sim$26~yr from a naive single power-law extrapolation. While $\alpha \approx 2$ provides a useful global description of the flare frequency distribution, the steepening area-productivity relation and the divergence between C/X and M/X derived slopes both point to a deficit of the most energetic flares ...

We study the spin transport property of a spin nematic liquid in a frustrated zigzag spin chain in a magnetic field from the perspective of the time evolution of wavepackets by a time-dependent density-matrix renormalization group method. We use the periodic boundary condition to avoid an edge-induced magnetization structure in the open boundary condition. We find that at the saturation, a magnon-pair wavepacket of momentum k=pi stays localized, since the gapless dispersion due to the antiferro-quadrupole quasi-long-range order has a rather flat structure, indicating zero propagation velocity.

Gravitational instability is a fundamental mechanism driving collapse of interstellar gas, yet in dynamically evolving environments such as galaxy mergers, external tidal fields can significantly alter the conditions for collapse. In this work, we develop an analytical framework to investigate how the tidal field of a companion galaxy modifies the classical Jeans instability by incorporating its anisotropic and time-dependent nature into the dispersion relation. We find that the tidal field introduces a critical angle between the cloud's position vector and the merger axis, $\theta_c \approx 54.7^\circ$, separating disruptive and compressive regimes of the radial tidal component. Disruptive tides suppress instability by increasing the characteristic length scale and restricting the range of unstable modes, whereas compressive tides enhance collapse by extending the unstable spectrum and increasing the growth rate of perturbations. The impact of tidal fields depends sensitively on gas density, being significant in diffuse media but negligible in dense molecular environments where the classical Jeans limit is recovered. All tidal effects peak near pericentric passage due to the strong dependence on galaxy separation. Since the free-fall time of diffuse gas is comparable to the duration of the close passage, tidally assisted collapse in the diffuse medium lags pericentre by roughly a free-fall time, whereas dense gas responds essentially instantaneously. These results demonstrate that companion-induced tidal fields play a key role in regulating the scale and efficiency of gravitational instability of diffuse interstellar gas in galaxy mergers. The code underlying this work is publicly available.

We study how holographic phase transitions imprint their scaling laws on the local Kasner geometry inside Einstein-scalar black holes. At fixed double-trace coupling, we derive the near-critical scaling of the deviation of the first-epoch Kasner exponent from the Schwarzschild value: $p_t^{(1)}+\frac{1}{3} \propto O^2 \propto (T_c-T)^{1/r}$, where $O$ denotes the boundary condensate and $r$ labels ordinary criticality ($r=1$), tricriticality ($r=2$), and higher multicriticality ($r\geq3$). A super-exponential scalar potential generates a sequence of Kasner epochs separated by scalar-field bounces. We further find that any later epoch that can be tracked continuously across the transition inherits the same temperature exponent, while its coefficient depends on the epoch. Numerical solutions confirm these predictions for the ordinary and tricritical cases. Finally, we show analytically that the leading irrelevant exponent of the infrared fixed point governs the low-temperature Kasner scaling, and verify the resulting scaling numerically for the first Kasner exponent.

Lyman Break Galaxies (LBGs) are actively star-forming galaxies identified through their characteristic rest-frame ultraviolet spectral break, making them powerful probes of galaxy evolution across cosmic time. We present a search for LBGs at redshifts $1.6 \leq z \leq 3.0$ in the GOODS-North field using the dropout technique combined with color selection from the 3D-HST data. We utilize two selection criteria to identify LBG candidates at $z \sim 2.1$ and $z \sim 2.7$ via F275W- and F336W-dropouts, yielding 192 and 135 newly identified LBG candidates in the redshift ranges $1.6 \leq z \leq 2.3$ and $2.3 < z \leq 3.0$, respectively. We estimate the physical properties of the LBG candidates, including stellar age, stellar mass, and star formation rate (SFR), using spectral energy distribution (SED) fitting. Morphological analysis shows that the majority of galaxies in our sample exhibit disc-like structures. Overall, the results indicate that these LBGs are low- to intermediate-mass compact galaxies with effective half-light radii of approximately 3.5 kpc.

It is shown that the convective gain of Stimulated Raman Backscatter (SRBS) within a single laser wavelength in the strongly coupled regime is equivalent to the Pierce parameter commonly used to describe high gain x-ray Free Electron Lasers (XFELs). The comparison utilizes the fact that the gain is a Lorentz invariant so the Pierce parameter is written in terms of the FEL parameters in the electron beam's rest frame. It is thus inferred that there is a direct correspondence of the physics between SRBS in the strong-coupled regime and high gain XFELs in the Compton regime.

Massive moons around rocky exoplanets are expected outcomes of giant impacts, yet no exomoon has been securely confirmed. We address this problem using meshless finite-mass simulations of giant impacts between differentiated rocky planets that include stellar tidal and Coriolis forces in a local co-rotating frame for orbital periods of 1–300 days, and compare these simulations with otherwise identical collisions in isolation. We find that stellar perturbations impose a severe formation-stage bottleneck on moon-forming disks. Ultra-short-period impacts leave essentially no surviving circumplanetary disk, whereas 10-day systems retain only strongly depleted, radially truncated, and dynamically compact disks. High impact velocities, expected for close-in planets, are devastating for disk generation, while retrograde impacts can slightly compensate for disk mass depletion. These results show that stellar perturbations can suppress exomoon formation around close-in rocky planets, reshaping expectations for the demographics of exomoons.

In the Pearl–London theory, the edge-barrier-disappearance field of a superconducting thin-film strip depends on an arbitrary short-distance core cutoff because the vortex is treated as a point object. The theory does not determine the cutoff or how it depends on temperature $T$, and therefore cannot determine the $T$ dependence of the instability field. Here we formulate the microscopic stability problem directly for the vortex-free superconducting state. This removes the core-cutoff ambiguity and determines the instability field $B_s$ over the full temperature range and across all width regimes considered here. For a homogeneous dirty strip with negligible self-field, three width regimes occur. For $W<W_1(T)$, superconductivity disappears continuously into the normal state through a one-dimensional (1D) instability. For $W_1(T)<W<W_2(T)$, an edge-selective two-dimensional (2D) long-wavelength mode becomes unstable. For $W>W_2(T)$, the critical wave number is finite and the unstable mode is localized near an edge. In the wide-strip limit, $B_s\propto1/W$, recovering the Pearl–London scaling. In sufficiently narrow strips, however, the Pearl–London edge-barrier picture fails qualitatively.

We consider a quantum system on the real line obeying a deformed Heisenberg algebra originally proposed by Wigner in 1950. Its explicit coordinate representation was provided by Yang in 1951 and in essence is identical in form with Dunkl's difference-differential operator introduced in 1989 in connection with roots systems of refection groups. Under certain conditions such quantum systems exhibit a supersymmetric (SUSY) structure where the reflection operator acts as the grading operator. We present a generalisation of Yang's representation by first considering only of one the two equations of motion in phase space. The corresponding non-interacting system is found to represent Witten's model of SUSY quantum mechanics. Imposing also the second equation of motion the original result of Wigner and Yang is reconsidered by extending their discussion to general symmetric potentials on the real line. As explicit example we discuss the harmonic oscillator and an attractive Coulomb-like potential $V(x)=-\gamma/|x|$. We also establish a Hooke-Newton duality between this Coulomb-like system and the original Wigner-Yang harmonic oscillator system.

We reconstruct the 2PI vertex $\Gamma(k,p;q)$ from Monte Carlo measurements of the connected two-particle correlator for the two-dimensional single-component $\phi^4$ lattice field theory and follow it across the Ising transition. Resolving the vertex in the irreducible representations of the point group $C_{4v}$, we find that the instability is driven by the $A_1$ (ferromagnetic) channel at zero transfer, whose leading eigenvalue of the symmetrized Bethe–Salpeter kernel approaches unity. Substantial $B_1$ (nematic) and $B_2$ (diagonal nematic) contributions cooperate with $A_1$ across all system sizes, highlighting that the soft sector is multidimensional. In real space, the vertex is short-ranged away from criticality while it develops a power-law tail at the critical point. In the ordered phase, the $q=0$ eigenvalue collapses because the ferromagnetic weight has condensed into the (one-particle-reducible) order parameter (or collective coordinate for a finite system), although finite-momentum fluctuations persist. By stripping the crossed-channel ladders, we obtain the fully irreducible vertex, which is a local contact – to a very good approximation. Inserted into the parquet and Schwinger–Dyson equations, this contact reproduces the Monte Carlo self-energy with an accuracy better than one-tenth of a percent. This provides a first-principles benchmark of the dynamical local-vertex approximation (D$\Gamma$A). Additionally, we demonstrate that in the critical region, the physical solution of the parquet equations behaves as a repulsive fixed point, driven initially by a single order-parameter mode.

High-coherence superconducting cavities offer a promising platform for quantum information, with long coherence times and negligible intrinsic dephasing. However, cavity control generally relies on nonlinear Josephson elements whose frequency fluctuations are inherited by the cavity as dephasing, potentially limiting control fidelities and eroding the noise bias used in error-correction protocols. Here, we introduce Stark-Assisted Flux-noise Evasion (SAFE), a hardware-efficient protocol that protects the cavity from inherited dephasing using only a weak off-resonant microwave drive applied to the nonlinear element. As a concrete setup, we analyze a 3D superconducting cavity dispersively coupled to a flux-tunable transmon (FTT) subject to $1/f$ flux noise. Analytical predictions are confirmed by Monte Carlo simulations with realistic parameters, which show that SAFE can extend the cavity dephasing time by more than an order of magnitude while keeping residual drive-induced decoherence subdominant.

Direct time-domain measurements of electric fields enable sub-cycle spectroscopy of light-matter interactions, but established techniques such as electro-optic sampling are constrained in their bandwidth by gate-pulse duration and phase-matching limitations. Alternative approaches have emerged in recent years based on asymmetric interferometric nonlinear cross-correlations with highly nonlinear media, and have demonstrated, for example, the field-resolved study of exciton ensembles. However, these nonlinear cross-correlation-based techniques have been benchmarked almost exclusively by self-referenced pulse characterization rather than by their quantitative spectroscopic performance, and all-optical approaches have received less attention than those based on direct charge emission. Here we extend all-optical asymmetric interferometric cross-correlation to higher nonlinearities in sub-wavelength films and demonstrate field-resolved spectroscopy of the free-induction decay of two ro-vibrational bands of ambient water vapor with a performance comparable to state of the art electro-optic sampling. The measurement spans 190 THz of bandwidth (80 THz to 270 THz) with sub-500 GHz spectral resolution, a spectral intensity dynamic range of six orders of magnitude, and a field-strength noise floor of 100 kV per meter. We anticipate the rapid adoption of here presented all-optical sampling to many experimental settings and a broad impact beyond the ultrafast optics research community as it is drastically simplified in comparison to ionization based techniques and allows the translation of electro-optic-sampling-level sensitivity into higher frequency ranges not previously accessible by conventional tools.

Magnetic vortices in individual nanoparticles are fundamental spin structures that govern the properties of next-generation magnetic devices and biomedical applications. However, directly imaging their complete structure, from the circulating in-plane magnetization to the nanometer scale out-of-plane core, remains challenging. Here, direct and quantitative visualization of magnetic vortex structures in individual cobalt nanoparticles is achieved by integrating a time-reversal methodology with tilt-scan-averaged differential phase contrast scanning transmission electron microscopy in a magnetic-field-free environment. This approach enables magnetic imaging in conjunction with atomic-scale analysis and reveals a correlation between particle geometry and internal demagnetizing fields. In addition, dynamic evolution of the vortex under in situ magnetic-field application is tracked, enabling unambiguous determination of the out-of-plane core polarity. This approach provides a powerful platform for correlating atomic-scale structure and magnetism within individual nanoparticles and for understanding the origins of nanoscale magnetic properties, thereby supporting the rational design of advanced nanomagnetic materials and devices.

Optically addressable solid-state spin defects have emerged as powerful multimodal quantum sensors, with nitrogen-vacancy (NV) centers in bulk diamond providing benchmark quantum control and sensitivity under ambient conditions. Embedding such defects in nanodiamonds (NDs) extends these capabilities to mobile probes capable of accessing complex biological and nanoscale environments. Reduced dimensions, however, introduce constraints beyond volumetric spin impurities, notably enhanced lattice strain and surface-induced noise sources, which shorten NV spin relaxation times (T1 and T2) and destabilize the NV charge state, as well as resulting in pronounced particle-to-particle variability in NDs typically produced by top-down approaches. These effects complicate both sensing performance and the quantitative interpretation of multimodal signals in realistic environments. This article provides a structured perspective on the physical mechanisms by which material properties constrain NV behavior in NDs, together with mitigation strategies that shape the robust use of these mobile quantum sensors for biosensing and nanoscale science.

Partial dynamical symmetry (PDS) is an algebraic structure in which a symmetry is neither exact nor fully broken: a subset of eigenstates keeps good quantum numbers and stays solvable while the rest mix. It is currently identified from spectroscopy. We ask whether it also leaves a purely structural mark in the eigenstates, and find, for the $sd$-IBM Hamiltonians studied here, that it does, though not in the magnitude of entanglement. The diagnostic is the variance of a symmetry Casimir, the label variance $\Var\,\C[G]$, which shares its zero with a block-coherence entropy and a block impurity: all three vanish when a state occupies a single Casimir sector, a single irreducible representation once conjugate representations are resolved by the cubic Casimir. Resolved state by state, the variance is numerically zero on the symmetry-selected subset and large on the mixed states, isolating the PDS states from the wavefunctions alone; the separation does not close as the boson number grows and persists at Leviatan's first- and second-order critical points, whereas the magnitude of bipartite $s|d$ entanglement does not separate the two families. We anchor the analysis in $^{168}$Er, reproducing Leviatan's fitted $\su3$ admixtures and his Hamiltonian-parameter-independent $\gamma\!\to\! g$ $B(E2)$ ratios. The diagnostic also has an exact dynamical form, a Casimir Loschmidt echo rigid on the symmetry-pure states, and we demonstrate its readout on an IBM superconducting processor at $N=3$, where a single solvable/mixed exemplar reproduces the predicted pattern within finite-shot uncertainties.

We investigate how molecular orbitals used as the basis of wave function expansion and how operator coefficient-based and locality-based Hamiltonian truncation affects the computational cost of Trotter decomposition-based Hamiltonian simulation in one-dimensional hydrogen chain systems. The analysis is performed using both Hartree–Fock canonical molecular orbitals (CMOs) and Pipek–Mezey-based localized molecular orbitals (LMOs). For short hydrogen chains, we evaluate the ground-state energy and fidelity and find that, in the CMO-based wave function expansion, introducing a threshold on Hamiltonian coefficients is effective in reducing the gate cost while maintaining computational accuracy. In contrast, in the LMO-based wave function expansion, operator locality-based Hamiltonian truncation is found to be more effective. By fitting the relationship between the truncation threshold and the ground-state energies and fidelities with empirical formulas, we estimate the threshold values required to achieve high fidelity ($F \ge 0.99$) in the ground-state wave function. Using the estimated thresholds, we then perform quantum gate resource estimation for longer hydrogen chains up to H$_{100}$. The results suggest an exponential advantage of the LMO-based wave function expansion with Hamiltonian truncation: the number of quantum gates required for Hamiltonian simulation grows polynomially when the CMO-based wave function expansion with operator coefficient-based Hamiltonian truncation is adopted, whereas it grows polylogarithmically when the LMO-based wave function expansion is combined with operator locality-based Hamiltonian truncation. These results provide useful guidelines for choosing orbital representations and Hamiltonian truncation strategies in large-scale quantum chemical simulations.

Non-Gaussian operations can reshape the photon statistics of continuous-variable probes, but their metrological advantage is meaningful only when heralding probability and photon-number resources are counted consistently. We compare photon subtraction, photon addition, and photon catalysis as input-side heralding operations in a balanced SU(1,1) interferometer with parity detection. A unified finite-transmissivity map supplies closed conditional moments and the corresponding quantum Fisher information at arbitrary operation order; internal loss is absorbed into a single effective parity observable whose lossless limit recovers the ideal pulled-back measurement. At fixed preparation parameters, single-photon subtraction and addition improve the conditional phase information over the Gaussian reference across most of the high-transmissivity regime, while multi-photon catalysis opens useful low-transmissivity windows. However, when the coherent–squeezed allocation is independently optimized at fixed conditional-probe energy and fixed interferometer gain, the success-weighted Fisher information of all three non-Gaussian operations remains below the optimized Gaussian benchmark. This conclusion is subject to the tested constraints: single-photon operations, a coherent-plus-squeezed-vacuum Gaussian family, fixed gain, and parity readout. Photon catalysis separately generates a conditional branch with high local quantum Fisher information that dark-point parity extracts poorly, identifying a measurement mismatch rather than a state-preparation failure. The result draws a sharp boundary between conditional non-Gaussian enhancement and practically available precision under explicitly stated resource constraints.

We extend the Carter-Govan multiple-scales analysis of weakly viscous, narrowband deep-water wave packets beyond Dysthe order within the potential-flow reduction of Dias, Dyachenko, and Zakharov (DDZ). We seek to determine whether this framework generates the complex multiplier $(1 + i\beta)$ used phenomenologically to modify the nonlocal Dysthe mean-flow interaction. Although order counting places a direct viscous carrier-mean interaction at sixth order, it does not exclude an indirect fifth-order contribution arising from viscosity dependent lower-order harmonics and nonlinear interactions. We therefore derive the first correction to the induced mean flow and the complete fifth-order first-harmonic solvability condition. The resulting nonlocal terms are derivative–dependent and contain no explicit viscosity, excluding the proposed indirect mechanism within the DDZ framework. At sixth order, a restricted calculation of the nonlinear viscous block isolates a direct carrier-mean contribution with the same operator structure as the imaginary component of the prescribed mean-flow correction. Independently, a finite-adjustment-time model yields an exact, frequency dependent mean-flow response. Its low-frequency expansion produces the multiplier $ 1 + i\beta_{\mathrm{eff}}(\Omega)$, with $\beta_{\mathrm{eff}}(\Omega) =\Omega\tau.$ When $\Omega\tau = \mathcal O(\epsilon)$, the resulting phase-lag correction enters at fifth order, one order beyond the leading Dysthe mean-flow interaction.

We study how three physically motivated dark matter equations of state alter the spacetime geometry of static, spherically symmetric black holes in General Relativity. The models considered are anisotropic perfect fluid dark matter (PFDM), isotropic constant-$\omega$ dark matter, and Bose-Einstein condensate (BEC) dark matter with a polytropic equation of state (EoS). For each model, we derive the Einstein field equations and solve for the metric function analytically in the PFDM and constant-$\omega$ cases, and numerically via the Tolman-Oppenheimer-Volkoff equations for BEC dark matter. We then compute the key strong gravity observables: event horizon radius, photon sphere radius, black hole shadow radius, innermost stable circular orbit (ISCO), and circular orbital velocity profiles. The shadow radii obtained for each model are compared against the Event Horizon Telescope constraints to place bounds on the dark matter parameters. Physical viability is assessed through the null, weak, dominant, and strong energy conditions, along with causality requirements on the sound speed. Our results show that PFDM produces near Schwarzschild geometry with mild anisotropic corrections, the constant-$\omega$ model is strongly restricted by causality to $0 \leq \omega \leq 1$, and BEC dark matter generates smooth, bounded deviations governed by the bosonic self-interaction parameter K. Taken together, these findings show that strong gravity observables can serve as practical tools for distinguishing between competing dark matter models through their geometric imprints on black hole space times.

We derive an analytic correspondence between multipartite concentratable entanglement (CE) and quantum phase transitions in one-dimensional quantum spin systems. We prove that CE shares the same analyticity structure as generalized order parameters, identifies the same quantum phases, and, for Gaussian ground states, is completely determined by the same single-particle correlation matrix. Numerical validation on the transverse-field Ising and generalized cluster-Ising models confirms these analytical predictions for both symmetry-breaking and symmetry-protected topological quantum phase transitions. Since CE can be measured directly using a constant-depth parallelized SWAP-test circuit, our results establish CE as an experimentally accessible, model-independent probe of quantum phase transitions without requiring model-specific order parameters.

We study a static, circularly symmetric deformation of the non-rotating BTZ black hole obtained by inserting a smooth transition function into the inverse radial metric component, $g^{rr}=S_\delta(r)F(r)$ with $S_\delta=\tanh[(r-r_h)/\delta]$, leaving $g_{tt}=-F$ untouched. This was motivated by the proposal that such a construction realizes a Lorentzian-to-Riemannian signature change at the horizon; we show that it does not. In coordinates $r-r_h=q^2$ with an advanced time, the metric extends real-analytically across $r=r_h$, and the extension is Lorentzian: $q=0$ is a regular null hypersurface, a degenerate Killing horizon with vanishing surface gravity, beyond which lies a second, isometric copy of the exterior. The areal radius has a minimum there, so the geometry is a black bounce; the would-be Riemannian branch is a separate geometry the Lorentzian sector never reaches. We give the effective source in closed form, an invariant account of the energy conditions, and identify the near-throat geometry as AdS$_2\times S^1$. The scalar effective potential is proven strictly positive for every mode, and the throat circle is a minimal surface whose length gives an entropy $\pi r_h/2G$, reproduced independently by the Wald–Noether charge and by a Cardy estimate from the computed Brown–York mass – concordant results for which no first law is available since $\kappa=0$. The throat carries an Aretakis-type instability, with a conserved leading transverse derivative and a linearly growing subleading one. We also record a negative result: smoothing $g_{tt}$ instead, as in the Lorentzian-Euclidean Schwarzschild proposal, is singular at the horizon for any finite smoothing width. We state explicitly what the construction does not establish.

Recently, Comisso and Asenjo proposed a new mechanism for energy extraction based on magnetic reconnection of plasma within the ergosphere. In this paper, we analyze the power and efficiency of energy extraction through magnetic reconnection in a rotating four-dimensional Einstein-Gauss-Bonnet gravity black hole. Firstly, we analyze the background properties of this spacetime and its physical quantities, including the event horizon, the boundary of the ergosphere, and the size of the ergosphere. We analyze the magnetic reconnection in circular orbits and investigate the energy extraction region, as well as the power and efficiency of energy extraction. Our results indicate that energy extraction remains feasible even for a low spin parameter of $0.4$, which is well below the previously reported threshold. We also find that the energy extraction power exceeds that of the Blandford-Znajek mechanism. The Gauss-Bonnet coupling parameters $\alpha$ lower the spin threshold for energy extraction. Similarly, we analyze the energy extraction region in the plunging regime, together with the corresponding power and efficiency. We find that energy extraction is possible even for a low spin parameter as $0.22$. We also observe that the Gauss-Bonnet coupling parameter $\alpha$ further lowers the spin threshold. This behavior is consistent with that observed in the circular orbit case. Finally, we compare the energy extraction power in the plunging and circular orbit regimes and find that the plunging regime yields a higher energy extraction power than the circular orbit case.

We investigate interfacial dynamics and multiscale energy transfer in immiscible Rayleigh-Taylor turbulence using numerical simulations with varying surface tension coefficients $\sigma$. Capillarity is shown to control characteristic length scales, interfacial area, and global energy and enstrophy budgets. The flow exhibits self-similar evolution with respect to surface tension, with the maximum kinetic energy scaling as $\sigma^{1/2}$ and the flow duration as $\sigma^{-1/4}$. A scale-by-scale budget shows that surface tension removes kinetic energy at large scales while injecting it at small scales, with the crossover occurring near the Hinze scale. We further recast and verify a local kinematic relationship between surface-tension power and interface stretching, up to conservative transport, $ \boldsymbol{f}^\sigma\cdot\boldsymbol{u} = - \sigma\mathcal{S}~|\nabla c| + \mathrm{Transport}$, where $\boldsymbol{f}^{\sigma}$ is the surface-tension force, $\boldsymbol{u}$ the velocity, $c$ the heavy-fluid volume fraction, and $\mathcal{S}$ the interface stretch rate. This relation links kinetic-energy transfer to the scalar-variance cascade and shows that energy transfer to the interface is governed by local strain. Statistics of individual bubbles and droplets reveal vertically elongated filaments with diameters of about three capillary scales, yielding a linear volume-area relation. Their vertical velocities scale with the square root of equivalent diameter, consistent with drag-buoyancy balance. These findings, particularly the direct link between surface tension power and resolved interface stretching, provide a rigorous physical framework for developing subgrid-scale closures for large eddy simulation of immiscible turbulent flows.

Theoretical interpretations of horizon-scale observations often rely on the idealized assumption of an isolated vacuum Kerr geometry. However, astrophysical black holes are expected to be embedded within dense dark matter distributions that can modify the local spacetime geometry. In this work, we propose a theoretical framework to model a rotating compact object surrounded by a bounded dark matter envelope governed by a Modified Chaplygin Gas (MCG) equation of state. To ensure strict adherence to the Einstein Field Equations, we construct a piece-wise, three-region spacetime using a fully coupled Tolman-Oppenheimer-Volkoff (TOV) integration, allowing the fluid's pressure to taper naturally to zero and dynamically define the outer boundary. Rotation is introduced via a pressure-corrected Kerr-form ansatz where the temporal component is obtained directly from the integrated hydrostatic potential. Using this geometrically rigorous configuration, which explicitly evaluates the exact 4D equatorial metric determinant rather than relying on vacuum approximations, we solve the circular equatorial geodesics and determine the innermost stable circular orbit (ISCO). Evaluating the thin accretion disk thermodynamics via the Novikov-Thorne formalism reveals that the deep gravitational potential well of the MCG envelope acts as a strong driver for viscous dissipation, systematically shifting the peak thermal flux, effective temperature, and multi-colour blackbody spectral luminosity to higher energy bands. Furthermore, we identify a clear structural degeneracy: a static or slowly rotating black hole embedded in a dense MCG structure can elevate radiative efficiencies up to $\eta \approx 6.5\%$. This framework is presented as a structured proposal to quantify environmental systematic uncertainties in standard black hole spin-estimation techniques.

The naive-$T$-odd angular coefficients $A_5$–$A_7$ in Drell–Yan production are highly suppressed in the Standard Model (SM), making them sensitive probes of CP-violating interactions beyond the SM. We study these observables within the Standard Model Effective Field Theory (SMEFT), focusing on dimension-six electroweak and chromomagnetic quark dipole operators. Due to their chirality-flipping structure, the leading contributions from CP-violating dipole interactions arise at $\mathcal{O}(1/\Lambda^4)$ through the interference between electroweak and chromomagnetic dipole amplitudes. We find that the sensitivity is primarily driven by $A_6$ and $A_7$ in the high dilepton transverse momentum region, where the dipole contributions are enhanced, while $A_5$ remains largely insensitive. Combining the ATLAS and CMS measurements, we constrain the CP-violating dipole combinations of Wilson coefficients at the $\mathcal{O}(0.1)$ level for $\Lambda=1~{\rm TeV}$. Assuming statistically dominated uncertainties at the HL-LHC, the sensitivity can be improved to the $\mathcal{O}(10^{-3})$ level. Our results highlight $A_6$ and $A_7$ as complementary probes of CP-violating dipole interactions at hadron colliders.

Layered IV-VI semiconductors such as GeSe exhibit strong in-plane optical anisotropy, making them promising candidates for polarization-sensitive photonic devices. However, realizing these properties in scalable platforms requires heteroepitaxial integration on technologically relevant substrates like GaAs. Direct growth of GeSe is complicated by its glass formation at low temperatures and high vapor pressure at elevated temperatures. To overcome this, we develop a method for ex-situ solid-phase epitaxy utilizing a SnSe buffer and offcut GaAs substrate to enable single-orientation crystalline GeSe films. Using polarized reflection measurements, we find that stabilizing a single-in-plane-orientation results in a 2x increase in anisotropic response between the armchair and zigzag directions. This work provides a new integration route to harness the anisotropic optical properties of GeSe and its alloys for polarization-sensitive technologies.

A classical linear code $C$ of length $n$ is said to have symbol locality $(r, \delta)$ if for any index $j$ there exists a repair group $J_j \subseteq \{1, \ldots, n\}$ with $j\in J_j$ and $|J_j| \leq r+\delta-1$ such that any $\delta-1$ or fewer erasures in $J_j$ can be corrected by using codeword symbols only in $J_j$. Later it turned out that this way of defining $r$ overestimates the number of necessary codeword symbols for multiple-erasure correction, and information locality was proposed to define $r$ as the dimension of the punctured code of $C$ onto $J_j$. Recently locality $(r,\delta)$ was proposed for quantum error-correcting codes by following the original definition of symbol locality $(r, \delta)$. We propose a quantum counterpart of the information locality for quantum stabilizer codes constructed by Hermitian orthogonality, and a linear algebraic procedure computing a smaller repair group predicted by the proposed information locality and simultaneously reducing the number of measured observables in decoding to its minimum possible value. Then we demonstrate that the previously proposed definition of quantum locality $(r,\delta)$ has the same drawback of overestimating the number of necessary codeword symbols for erasure correction by providing an explicit example of a quantum stabilizer code. Finally, we will give another example of a quantum stabilizer code constructed by Euclidean orthogonality and two different linear codes, with which a natural translation of the classical information locality into the quantum setting underestimates the number of necessary codeword symbols for erasure correction.

Neural surrogates offer a promising route to accelerating computationally expensive simulations governed by partial differential equations across science and industry. Their practical deployment, however, is limited by unreliable predictions under out-of-distribution (OOD) conditions. We develop a solver-coupled surrogate-Newton framework that uses surrogate predictions as high-quality initial guesses for Newton-Krylov iterations, thereby combining rapid global flow-field prediction with high-accuracy numerical convergence at the terminal stage. On an OOD benchmark comprising geometries sampled from actual transonic airfoil optimization trajectories, the framework lowers the median residual L_2 ratio by over seven orders of magnitude while substantially reducing field and aerodynamic errors. In practical supercritical airfoil optimization, it improves online prediction reliability while achieving a 15.5-fold generation-level speedup over CFD. We further test the framework's extension to three dimensions using a flying-wing dataset. Together, these studies demonstrate the potential of surrogate-Newton coupling to deliver accurate, efficient and scalable steady CFD across industrial workflows.

In this work, we evaluate the decay widths and branching ratios of the heavy top partner $T$, and perform a comprehensive phenomenological study of its pair and associated production at a muon collider within the framework of the Bestest Little Higgs Model (BLHM). The BLHM provides an attractive and natural mechanism for addressing the fine-tuning problem in the Standard Model (SM) of particle physics. In our study of the top partner $T$, we consider the production processes $\mu^{+} \mu^{-} \to (\gamma, Z, Z', h, H) \to T \bar{T}$ and $\mu^{+} \mu^{-} \to (\gamma, Z, Z', h, H)\to \bar{t}T+ t \bar{T}$, and we explore different center-of-mass energies of the muon collider to perform our numerical analysis of the production cross sections for the processes of interest. Our results show that pair production is the most promising channel for probing the top partner of the BLHM at a future muon collider.

The clustering pattern of zeros in the ground state of a fractional quantum Hall system is a defining feature of its topological properties. We analyze the geometrical fluctuations of the zeros around individual electrons and propose to use the displacement ratio of the zeros to visualize and measure the distance of a realistic state to a model wave function. The distribution of the zero displacement ratio behaves like an order parameter in the transition from a Laughlin phase to a topologically trivial one. The statistical comparison between quantum Hall states belonging to different Jain sequences leads to a composite fermion fluid description of the $\nu = 1/5$ ground state with long-range Coulomb interaction that agrees almost perfectly for as few as $3$-$5$ electrons, overcoming the long-standing difficulties of accommodating the competing liquid and crystal orders at short distances.