Papers

We study the dynamics of observables that are conserved under the Hamiltonian evolution of a closed quantum system, but cease to be conserved when the system is coupled to a Markovian environment and described by a Lindblad master equation. Starting from the adjoint Lindblad equation, we derive elementary expressions for the time derivatives of the expectation value and second moment of an observable $O$, with particular emphasis on the case $[H,O]=0$ but $\mathcal L^\dagger(O)\neq 0$. These formulae provide a direct assessment of how collapse operators break Hamiltonian conservation laws and generate fluctuations of formerly conserved quantities. The discussion is illustrated by analytic examples: one-qubit amplitude damping, a two-qubit excitation-number model, a momentum-diffusion model in which the mean is conserved while the variance grows, and the Jaynes-Cummings model. The latter also shows the complementary case of a reservoir coupled through a conserved quantity, where dephasing can occur without changing the statistics of that quantity. We finally comment on the relation between Lindblad source terms and idealized wave-function reduction models in which local conservation may hold only statistically.

In a recent paper, it was shown that the Covarying Coupling Constants and Tired Light (CCC+TL) hybrid model yields the Hubble parameter $H(z)$ that is substantially different from its measured value using differential aging of quiescent galaxies as cosmic chronometers (CC). It was claimed that the fit of the CCC+TL model to the $H(z)$ data results in a best-fit value for the parameter $\alpha$, defining the strength of the co-variation of the constants, disagreeing with that for the SN~Ia data at the $\sim 6\sigma$ level. In this paper we re-examine the assumptions underlying such a comparison. Cosmic-chronometer measurements are designed to be independent of cosmological priors, but they nevertheless rely on stellar population synthesis models, isochrones, and age-dating calibrations developed within standard stellar-evolution physics. Therefore, even before introducing any specific correction factor, the present CC compilation cannot be regarded as a model-independent falsification of CCC+TL without recomputing the relevant stellar population models in that framework. In the absence of such a recalculation, we ask a more limited question: what type and magnitude of modification to the effective differential-age relation would be sufficient to remove the claimed tension? We show that a phenomenological factor of the form $\sim (1+z_t)^{-3}$ with $z_t$ being the TL contribution to the observed redshift, motivated by the scaling of gas cooling times for galaxy formation in the CCC+TL framework compared to $\Lambda\text{CDM}$, is sufficient to reduce the apparent discrepancy in $\alpha$ to $\sim 0.13\sigma$. Since $z_t = 0$ for the stellar model primarily developed from local stellar observations, the stellar-aging methods may be unable to verify $\sim (1+z_t)^{-3}$ dependence.

Quantitative studies of gender in physics education have often used categorical gender identity measures, which are valuable for documenting broad inequities across gender groups but less suited for capturing variation within groups or for examining how students perceive and express their gender in particular contexts. Metrics targeting gender expression, such as gradational self- and reflected appraisal measures of femininity, masculinity, and androgyny, offer a complementary approach. Prior work using this approach in introductory physics identified substantial within-gender variation in students' appraisals and gender-patterned self-reflected appraisal discrepancies. Building on this work, the present study provides a cross-institutional replication by examining whether these patterns recur in a second institutional context. We examined students' self- and reflected appraisals of femininity, masculinity, and androgyny, self-reflected appraisal discrepancies, and associations between these discrepancies, sense of belonging, and gender stigma consciousness. Across institutional contexts, both studies showed substantial within-gender variation in all three appraisal dimensions and recurring directional discrepancy patterns. Higher gender stigma consciousness was consistently associated with the directional discrepancy patterns observed across institutions. Lower sense of belonging was consistently associated with negative femininity discrepancy across institutions and was also associated with positive masculinity discrepancy in the present study. These findings suggest that students' appraisals along gendered dimensions are both patterned and context-sensitive. More broadly, self-reflected appraisal discrepancy may offer a useful quantitative lens for examining students' perceptions of gender, with implications for understanding belonging and inclusion in physics learning environments.

This work is devoted to data-driven identification of discrete breathers in numerical simulations of a two-dimensional crystal lattice using locally sampled wave data. Different lattice wave datasets are considered, with data collected from regions of different shapes and sizes defined by the lattice particles in mechanical equilibrium. Specifically, in addition to regions with a regular hexagonal shape, one- and quasi-one-dimensional regions reflecting the quasi-one-dimensionality of discrete breathers in two-dimensional hexagonal crystal lattices are proposed. To improve numerical efficiency, dataset dimensionality is reduced using Principal Component Analysis, and highly accurate Support Vector Machine classifiers are trained to distinguish between linear and nonlinear wave data. The obtained classifiers, together with the sliding window method, are applied to detect localization regions in two-dimensional hexagonal crystal lattice numerical simulations. High-precision algorithms for detected localization region segmentation and localized wave directionality estimation within the detected regions are further proposed, and their performance is evaluated. The presented methods are successfully applied to detect localized waves and their collision regions, as well as their directionality, performing a numerical study of stationary and traveling two-dimensional discrete breather interactions. Qualitatively better results are obtained when considering wave-data collection regions respecting the quasi-one-dimensional nature of two-dimensional discrete breathers in the hexagonal crystal lattice model.

Quantum optimization offers a route to searching the large defect-configuration spaces that arise in materials design. We develop an end-to-end, constraint-aware quantum optimization workflow for composition-defect search in a doped ZrO2 thermal-barrier-coating (TBC) material system, using a MACE-MPA-0 energy dataset to fit a 24-variable QUBO over 8 cation-occupation and 16 oxygen-vacancy variables with exactly two rare-earth substitutions and one oxygen vacancy, yielding 448 feasible configurations. The QUBO surrogate reproduces the MACE energies with held-out R2 = 0.997 (full-data R2 = 0.999, RMSE = 17 meV). We validate two complementary quantum pathways against exact enumeration: a constraint-preserving XY-mixer QAOA that confines sampling to the feasible subspace and places 86% of probability mass within 1 meV of the MACE optimum at depth p = 3, and a fault-tolerant constrained Grover Adaptive Search oracle with explicit fixed-point arithmetic, branch-safe comparison, feasibility checking, and phase kickback. Across threshold cases, the validated oracle uses 324 high-level logical qubits, or 352 to 358 with conservative clean-ancilla v-chain accounting, and requires 3.6 to 4.3 x 104 Toffoli gates per Grover (GAS) iteration. An idealized feasible-space amplification estimate suggests up to a 240x reduction in total Toffoli cost relative to the full 224 occupation space, providing a resource-estimation bridge between materials-informed QUBO modeling, constraint-aware QAOA, and fault-tolerant threshold search.

Higher-order nondegenerate soliton solutions of the integrable Coupled Nonlinear Schrodinger system, known as the Manakov system, are obtained using the Darboux transformation associated with the Gram-determinant approach. Starting from the trivial seed solution, the explicit first and second-order soliton solutions are constructed through the direct iterative Darboux procedure. Owing to the rapid increase in algebraic complexity with successive iterations, the higher-order solutions are reformulated through a compact Gram-determinant representation, thereby establishing a unified and systematic framework for their construction. Using this approach, explicit third- and fourth-order solutions are derived, and the general Nth-order case is presented. The resulting structures exhibit asymmetric localized profiles with multiple intensity peaks arising from distinct spectral parameters. The collision dynamics of higher-order nondegenerate solitons reveal features such as asymmetric energy redistribution and complex interaction behaviour. The present formulation provides a systematic and explicit construction of higher-order nondegenerate solitons, offering new insights into multi-component nonlinear wave dynamics.

We present a gauge-theoretic formulation of Nambu non-equilibrium thermodynamics (NNET) within a common gauge-fixed worldline framework. In this formulation, the generalized thermodynamic force is described by an Abelian thermodynamic connection, and ordinary Onsager dynamics is recovered by fixing its temporal component through the dissipation function. To extend this construction to NNET, we introduce a closed two-form as additional geometric input. This form determines a divergence-free Nambu vector field and thereby defines a characteristic direction on the extended thermodynamic state space. The Onsager gauge condition is then generalized so that the dissipative gauge fixing is imposed along this Nambu characteristic direction. The resulting constitutive relation reproduces the basic NNET evolution equation, combining nondissipative Nambu circulation with dissipative Onsager relaxation. We further show that the localized BF-type expression is not an independent pre-gauge-fixed action, but a differential-form representation of the Nambu-adapted gauge-fixed worldline theory. The Faddeev–Popov operator associated with the BRST gauge fixing becomes, on shell, the negative of the material derivative along the full NNET flow, and its time-independent zero-mode profiles satisfy the same equation as first integrals of the deterministic dynamics. Finite residual transformations obey a Hamilton–Jacobi equation governed by the same Onsager tensor, implying that the gauge parameter is nonincreasing along the original NNET flow. These results provide a unified geometric interpretation of Onsager dissipation and Nambu dynamics within a single gauge-fixing framework.

We study how the Ostrogradsky modes can be removed in multi-field higher-order scalar-tensor theories. For a general class of theories with an arbitrary number $\mathcal{N}$ of scalar fields and quadratic dependence on their second derivatives, we perform an ADM decomposition and carry out the Hamiltonian analysis in the branch where the metric kinetic block is invertible. The primary degeneracy condition is a matrix condition in field space. Previous studies of coupled higher-derivative systems have shown that primary degeneracy need not by itself be sufficient. In the generally covariant multi-scalar-tensor setting considered here, where the scalar and metric velocities mix in the ADM decomposition, preservation of the primary degeneracy constraints generates additional consistency conditions. We obtain these conditions explicitly in terms of the ADM coefficient blocks generated by the covariant action. Some of these conditions are antisymmetric in the field-space indices and vanish in the single-field limit. A rank condition on the constraint algebra is required in addition. Under the assumptions used in the Hamiltonian counting, in particular that the scalar second-class sector leaves the diffeomorphism constraints first class, the theory then propagates $2+\mathcal{N}$ degrees of freedom, the two tensor modes of gravity and one scalar mode per field, with no additional Ostrogradsky mode. We check the conditions in the single-field limit and in a multi-field quadratic Horndeski-type subclass. We also give a subclass with nonzero scalar-metric kinetic mixing, constructed directly at the level of the ADM coefficient blocks, showing that the Hamiltonian conditions admit nontrivial solutions at the ADM-block level.

Investigating the spectroscopy and thermal stability of exotic multiquark states provides crucial insights into the fundamental confinement mechanisms of quantum chromodynamics (QCD) under extreme regimes. This work presents an innovative study of the spectroscopy and dissociation of fully-heavy tetraquarks in an anisotropic plasma via the generalized fractional derivative (GFD) structure. The radial Schrödinger equation (SE) with an extended Cornell potential that includes Debye screening and plasma anisotropy into account is solved by applying the parametric generalised fractional Nikiforov-Uvarov (PGFNU) technique. The analysis of systems consisting of $cc\bar c\bar c$ and $bb\bar{b}\bar{b}$ shows that the binding potential of the systems and the dissociation energy increase with the anisotropy parameter and decrease with temperature. The fractional paradigm also shows that when the fractional orders are lower, the systems will be more strongly bound than in classical quantum mechanics. Furthermore, the mass spectra for all considered tetraquark configurations, including the $cc\bar{c}\bar{c}$, $bb\bar{b}\bar{b}$, $c\bar{q}c\bar{q}$, and $b\bar{q}b\bar{q}$ systems, are calculated for both ground and excited states. These calculations were performed across both the fractional and classical regimes. The findings indicate that the GFD framework provides an effective mathematical basis for modelling hadronic systems in complex contexts, and they demonstrate significant agreement with earlier theoretical studies.

It was recently discovered that many self-interacting vector fields can have healthy time evolution when field amplitudes are small, however, further dynamics becomes impossible if the norm of the field reaches a certain finite value. This result was also generalized to higher form fields using the fact that vector fields can also be viewed as 1-form fields. However, other recent work demonstrated that some exceptional vector field theories do not suffer from such problems if the self-interaction term is chosen in a specific way. Here, we study whether a similar exception exists for $p$-form fields in general. We show that, in 4 spacetime dimensions, 3-form fields with self interaction can indeed have healthy time evolution similarly to vectors. However, the analogous coupling terms still lead to loss of hyperbolicity for 2-form fields. We study the reasons for these differences, and comment on directions to generalize our findings. We also demonstrate that eliminating the mass term, one of the proposals to build healthy self-interacting vector field theories, moves the singularity to other parts of the equations of motion, hence, most likely does not provide well-posed time evolution.

Line bundle cohomology on complete intersection Calabi–Yau threefolds is an important input in string phenomenology. Previous work, based on direct extrapolation and on machine-learning analyses of finite data sets, has shown that these cohomology dimensions often admit chamber-wise polynomial descriptions on the Picard lattice. In this paper we explain this structure through the Hilbert functions associated with the non-trivial maps in the Koszul spectral sequence. Once Bott–Borel–Weil theory determines the non-vanishing ambient cohomology groups, the rank defects of the relevant Koszul maps are governed by Hilbert functions of cokernel or kernel modules. This turns many empirical chamber formulae into explicit rank-defect statements, with proofs that are either analytic or certified on finite boxes. Using this approach, we recover analytically almost all of the piecewise formulae appearing in the existing literature. For the remaining cases, we prove finite-box certificate theorems for infinite families of line bundles in the specified regions. We also identify new wall structures on certain CICYs which refine the chamber decompositions suggested by finite-range data. Finally, we use the same framework to construct line bundle cohomology formula libraries for two CICY threefolds which had not previously been analysed in this way. These results suggest that Hilbert-function methods can provide promising faster inputs for future string model-building scans based on line bundle constructions.

We investigate collective Mpemba-type relaxation in a degenerate family of bosonic modes coupled to a common thermal reservoir. Starting from a fully symmetric M-mode description and employing a representative mean-field reduction, we derive effective master equations for weak-coupling Markovian, strong-coupling Caldeira-Leggett, and weak-coupling non-Markovian regimes. In the weak-coupling Markovian limit, relaxation separates into an incoherent thermal channel decaying at rate gamma and a collective coherent channel decaying at rate M gamma, yielding an explicit Mpemba crossing time determined by the initial-state preparation. In the strong-coupling Caldeira-Leggett regime, transient quadrature dynamics enriches the relaxation pattern, delaying crossings in the overdamped sector and generating multiple crossings in the underdamped sector. In the non-Markovian regime, reservoir memory reshapes the same channel-competition mechanism through time-dependent decay rates and a Lamb shift, producing delayed and clustered crossing windows. Numerical results based on the energy and the Kullback-Leibler divergence reveal Mpemba and anti-Mpemba behavior, criterion dependence, and multiple transient reorderings induced by collective coherence, quadrature dynamics, and reservoir memory.

Polycrystalline samples of LaMn1-xCoxO3 series over a wide compositional range (x = 0.1 - 0.9) were synthesized by microwave irradiation of oxide precursors and their magnetic and magnetostrictive properties were investigated. Magnetostrictions parallel (l_par) and perpendicular (l_per) to the applied magnetic field were measured to estimate anisotropic(l_anis) and volume magnetostrictions(l_vol). In all the compositions, l-par (l_per) is negative (positive) and (l_anis) >> (l_vol), suggesting dominance of anisotropic lattice distortion under a magnetic field. The value of l_anis at 10 K for H = 50 kOe initially increases with x from 178 ppm for x = 0.1 to a maximum of 1221 ppm at x = 0.5 before decreasing for higher x. The composition dependence of magnetostriction is asymmetric about x = 0.5, the decrease for x > 0.5 is more steeper than for x < 0.5 whereas saturation magnetization decreases monotonically with increasing x except for an abrupt change at x = 0.6. The largest anisotropic magnetostriction observed for x = 0.5 is attributed to the presence of high-spin Co2+ ions with a non-zero orbital moment in the maximum fraction whereas Mn3+/4+ or Co3+ ions play minor roles. The composition dependence of magnetostriction is suggested to arise from changes in the structure, valence states of Mn and Co ions and magnetic interactions among them.

Accurate NH3 pressure-broadening parameters are essential for reliable line-by-line simulations in atmospheric sensing, combustion diagnostics, and planetary/exoplanet studies. Current HITRAN NH3 self- and air-broadened half-widths rely largely on the Nemtchinov rotational correlation and database rules that clamp or assign default values beyond the validated range, limiting the representation of measured rotational trends, especially at high J”. Here, published NH3 self- and air-broadened Lorentz half-widths were compiled and reassessed to develop updated HITRAN-ready empirical correlations. The dataset includes 1317 self-broadened and 1231 air-broadened widths at, or reduced to, 296 K across multiple bands, branches, and rotational states. The analysis shows that linewidths are governed mainly by rotational dependence rather than branch, band, or vibration-inversion effects. Weighted, positivity-constrained third-degree polynomial fits were developed for gamma_self and gamma_air as functions of the branch-dependent index m and K”. The new correlations reduce the MAPE from 10.95% to 6.80% for air broadening and from 23.61% to 10.89% for self broadening relative to HITRAN2024. Comparisons with PNNL and pure-NH3 spectra further confirm improved absorption simulations, providing a physically constrained replacement for the current HITRAN NH3 broadening treatment.

We present a novel method to conduct targeted gravitational-wave searches for compact binary mergers using the GstLAL inspiral pipeline. By incorporating sky localization and timing information from external electromagnetic triggers, we enhance the sensitivity of the search for sub-threshold gravitational-wave signals associated with events such as short gamma-ray bursts. Our approach modifies the standard likelihood ratio ranking statistic to include a sky localization prior, allowing for a more focused analysis on specific regions of the sky. We demonstrate the effectiveness of this method through injection studies, comparing the performance of the targeted search against the standard all-sky search configuration. The results show a significant improvement in detection efficiency for signals consistent with the provided sky location and timing, while maintaining control over false alarm rates. This targeted search framework enables rapid follow-up of electromagnetic transients, facilitating multi-messenger astronomy efforts in the era of advanced gravitational-wave detectors.

We propose a noninvasive SQUID-based polarimeter for the polarized proton beam in the Electron-Ion Collider (EIC) Hadron Storage Ring (HSR), exploiting the collective magnetic dipole moment of the bunches rather than scattering. The six-snake HSR lattice has synchronous-particle spin tune $\nu_s = 1/2$, placing the in-plane spin-precession signal at half the revolution frequency ($\sim$39 kHz), in the DC SQUID band. Three pickup channels (cosine-$\theta$ and sine-$\theta$ saddle loops for the transverse components, a coaxial axial gradiometer for the longitudinal one) reconstruct the full polarization vector $(P_x, P_y, P_z)$ in two complementary modes. Static mode, the default for continuous noninvasive monitoring, reads all three components: $P_y$ at the revolution frequency and the residual in-plane components at $\nu_s f_\mathrm{rev}$, bunch by bunch over an hours-long fill, including $P_z$, inaccessible to single-spin scattering polarimetry by parity conservation. Dynamic mode gives a precise polarization-magnitude measurement: a longitudinal kicker tips a small fraction of the polarization into the horizontal (ring) plane to produce a free-induction-decay (FID) signal, and many phase-locked tip-$\pi$-echo-restore cycles are summed coherently via a matched filter across all bunches, with $\mathcal{O}(\alpha^2/\pi^2) \sim 10^{-4}$ loss per cycle, negligible over a full $\delta P/P = 1\%$ measurement. For tipping angle $\alpha = 30$ mrad, polarization $P = 0.7$, and effective rms spin-tune spread $\sigma_{\nu_s}^\mathrm{eff} = 10^{-3}$ (coherence time $\sim$2 ms), the integration time to reach $\delta P/P = 1\%$ is about 18 s at injection and 5 min at flattop. The architecture extends to deuteron and $^3$He beams via species-specific spin-magnetic factors, with applications to storage-ring EDM searches.

Periodic micro-pillar lattices integrated on elastic substrates provide a promising plat-form for controlling elastic-wave propagation through localized resonant interactions. In this work, defect-engineered resonant transmission in periodic tungsten micro-pillar arrays deposited on silicon substrates is numerically investigated using finite-element simulations. Two-dimensional frequency-domain analyses were performed to evaluate the influence of one-, two- and three-pillar defects on elastic wave transmission characteristics. The results reveal strong defect-width-dependent transmission modulation together with the localized resonant elastic-wave redistribution within the periodic lattice. Full three-dimensional simulations further confirm the presence of defect-sensitive resonant localization and modified elastic-wave transport pathways. Floquet dispersion analysis of a periodic unit cell reveals multiple nearly flat resonant branches associated with low-group-velocity elastic-wave modes, indicating predominantly subwavelength locally resonant behavior. A comparative study between tungsten and copper resonators demonstrates enhanced resonant confinement in tung-sten-based structures due to their larger inertial contrast with the supporting sub-strate. The proposed defect-engineered micro-pillar lattices provide an effective approach for frequency-selective elastic-wave control and localized resonant wave ma-nipulation in elastic metamaterial systems.

The persistent discrepancy between early-time and late-Universe measurements of the Hubble constant commonly known as the $H_0$ tension remains one of the most pressing open questions in modern cosmology. In this work, we explore whether modifications to the gravitational sector, specifically within the framework of symmetric teleparallel gravity, can offer a viable pathway toward alleviating this tension. We consider two functional forms of $f(Q)$ gravity: a logarithmic model and a nonlinear saturation model, both of which introduce geometric corrections to the standard expansion history without invoking a cosmological constant. Constraining these models through a Bayesian MCMC analysis against a comprehensive suite of observational data, including cosmic chronometers, Type Ia supernova compilations (Pantheon, Pantheon$+$SH0ES, and DES SN5YR), and BAO measurements from SDSS and DESI, we find that both models remain statistically competitive with $\Lambda$CDM. The logarithmic model, in particular, consistently infers intermediate values of $H_0$ between the Planck and SH0ES benchmarks across all dataset combinations, and carries lower AIC and BIC penalties, establishing it as the more promising candidate for partially easing the $H_0$ tension within a modified gravity framework.

Polycrystalline SrRu1-xCoxO3 (x = 0.0, 0.05) and CaRuO3 were rapidly synthesized (< 1 hour) by microwave irradiation of oxide powders, and their magnetic, magnetoresistance, thermal expansion, and magnetostriction properties were investigated. The microwave-synthesised SrRuO3 exhibits a ferromagnetic transition at TC = 160 K, metallic-type resistivity, and negative magnetoresistance, with magnitudes comparable to those of a sample synthesized by conventional heating over 24 hours. Upon lowering the temperature from 300 K, the linear thermal expansion shows a transition from the usual contraction in the paramagnetic state to spontaneous expansion in the ferromagnetic state (invar-like effect). The application of an external magnetic field at a fixed temperature results in isotropic expansion of the length, implying a positive magnetovolume effect. The volume magnetostriction is 40 ppm at 10 K in a magnetic field of 50 kOe, and it reaches a maximum value of 60 ppm close to TC. The spontaneous thermal expansion is diminished in SrRu0.95Co0.05O3. While the magnetostriction is anisotropic at 10 K, the isotropic behaviour is recovered above 80 K, and the maximum value of the positive magnetovolume is comparable to that of the parent compound. Our results suggest that the magnetovolume effect in SrRu1-xCoxO3 is related to competition between robust tilting/rotation of RuO6 octahedra and spin-orbit interaction of the doped Co2+ ions

The ordered iron nitride phase $\alpha''-\mathrm{Fe}_{16}\mathrm{N}_2$ is a promising candidate for environment-friendly, rare-earth-free permanent magnets due to its demonstrated giant saturation magnetization ($M_s$). However, first-principles electronic-structure calculations have struggled to consistently reproduce experimentally-observed high $M_s$, and have yielded highly variable magneto-crystalline anisotropy (MCA) values. In this work, we employ Density Functional Theory under the GGA+$U$ framework to study the effect of the Hubbard parameters $U$ and $J$ on the magnetic properties of $\mathrm{Fe}_{16}\mathrm{N}_2$. We demonstrate that the electronic structure exhibits high sensitivity to these parameters, specifically uncovering a van Hove singularity near the Fermi level ($E_F$), inherently tied to the material's structural and thermal phase instability. By linking this topological anomaly to the calculated magnetic properties, we demonstrate that the selection of $U$ not only tunes $M_s$ and MCA energy towards experimental values but also reveals an underlying electronic mechanism potentially responsible for the phase's metastability. This provides a framework for understanding the correlation-driven magnetic behavior of $\mathrm{Fe}_{16}\mathrm{N}_2$ and offers a pathway for optimizing its stability and performance in practical applications.

Large and persistent differences in opioid prescribing across physicians and regions cannot be explained by patient characteristics or physician attributes alone. We developed a behavioral framework in which prescribing evolves through persistence, exposure to peers in professional networks, and heterogeneous responses to a common policy signal that varies with network centrality. Using nationwide Medicare Part D data from 2013 to 2020, covering more than two million physician-year observations, we tested three hypotheses implied by this framework. Physicians exposed to higher peer prescribing subsequently prescribe more; more central physicians reduce prescribing more following the introduction of the 2016 CDC guideline, with no evidence of differential pre-trends; and changes in peer prescribing are closely associated with changes in individual prescribing in the post-guideline period. By 2020, physicians at the 90th percentile of network centrality exhibited prescribing reductions 0.30 percentage points larger than those at the 10th percentile, with the gap widening steadily after the introduction of the CDC guideline. Together, these results indicate that opioid prescribing operates through professional networks, in which policy effects spread through connections and appear to be shaped by network position. This suggests that engaging highly connected physicians may help extend the reach of opioid stewardship programs. It also raises questions about how the burden and benefits of such targeting would be distributed across physicians and patients.

We conduct a comprehensive dynamical analysis of quasi-two-dimensional (Q2D) dispersions of Brownian particles with competing short-range attractive (SA) and long-range repulsive (LR) interactions using Langevin dynamics (LD) and multiparticle collision dynamics (MPC). As the attractive interaction is strengthened, self-diffusion is significantly suppressed, and clustering gives rise to pronounced subdiffusive behavior. We find that cluster lifetimes are influenced more strongly by attraction strength than by particle concentration. Two dynamical criteria for the transition from non-clustered to clustered phases are identified in terms of the mean cluster lifetime and the relaxation time of local hexagonal order, respectively. Moreover, clustered Q2D-SALR systems exhibit pronounced non-Gaussian dynamics. In particular, the self-van Hove function in the equilibrium-cluster phase displays an approximately exponential form, consistent with an underlying diffusing-diffusivity mechanism. Importantly, MPC simulations reveal the critical role of hydrodynamic interactions (HIs) in collective dynamics. We observe that the anomalously enhanced large-scale collective diffusion characteristic of hydrodynamically interacting Q2D systems is qualitatively preserved in Q2D-SALR dispersions. However, this enhancement suppresses the intermediate-range-order peak in the hydrodynamic function compared to its three-dimensional counterpart. Furthermore, by analyzing the time-dependent evolution of hydrodynamic function and the sound mode in hydrodynamic correlations, we find that clustering in Q2D-SALR systems leads to an earlier onset of HIs than in Q2D hard-sphere reference systems, implying HIs become relevant already on inertial timescales.

Motivated by the discovery of superconductivity in Sr-doped infinite-layer nickelate films on SrTiO$_3$(001), we explore the broader landscape of $AB$O$_2$ oxides through comprehensive high-throughput first-principles simulations. Specifically, delafossites and their ordered rock-salt (111) variants stand out as intriguing layered oxides that share the infinite-layer $AB$O$_2$ stoichiometry and simultaneously retain a perovskite-like octahedral motif. This positions them as a unique structural bridge between these two phases and as promising candidates for novel correlated electronic states. We compile a phase diagram that compares the relative stability of these four distinct oxides across the periodic table. Surprisingly, we find that the delafossite structure rivals the infinite-layer phase in thermodynamic stability for the nickelates, and even more for the recently suggested palladate and platinate analogs. Comparison of the respective electronic structures reveals that the delafossite compounds, which we find to be characterized by reversed cation order, exhibit a strongly $d_{z^2}$-dominated Fermi surface, in stark contrast to the $d_{x^2-y^2}$ character observed in the infinite-layer phases. Among all candidates, the La-Ni combination stands out as a thermodynamic optimum for stabilizing the infinite-layer motif. Furthermore, we show that hole doping via Ca, Sr, and Ba systematically enhances the stability of the infinite-layer phase in all three transition-metal families. These results reveal fundamental challenges in realizing bulk substrate-free infinite-layer oxides, and simultaneously offer guidance for future experimental synthesis efforts targeting novel superconducting compounds.

Electrons in transition-metal dichalcogenides (TMDs) possess valley and spin degrees of freedom, which leads to rich exciton and exciton-polariton physics with nontrivial scattering dynamics and enhanced nonlinearities, presenting a key mechanism for photonic devices. Yet, existing descriptions of bosonization and polariton interactions in TMD-based systems overlook the valley degree of freedom as well as the various particles' spins combinations. In this work, we derive a nonequilibrium field-theory approach in the path integral formalism that allows to track all the polariton nonlinearities in the strong coupling regime. We demonstrate that, when all the bright and dark exciton species are considered, the TMD monolayer-based polariton systems feature sixteen different nonlinear contributions due to interactions and even more saturation-related terms. Strikingly, while the interactions of excitons within one valley are overall dominant, we show that the contribution to the blueshift from spin-dark excitons is much higher than that from bright intravalley excitons.

Exceptional points (EPs) are non-Hermitian spectral singularities where eigenvalues and eigenvectors coalesce. We propose a geometry-controlled route to EPs in orbital-angular-momentum (OAM) photonics. In an effective torsion-free helicoidal background, the twist supplies a signed, real chiral splitting between opposite-OAM modes, while openness, gain, loss, leakage, or channel coupling, supplies the non-Hermiticity. The EP is reached when the geometric detuning compensates for a residual mode splitting and the linewidth contrast meets the non-Hermitian balance condition; the twist rate is thus the control parameter, not the source of non-Hermiticity. We obtain the OAM slope both for a confined quantum problem and, in the paraxial regime, for a helically twisted guide, and embed the OAM doublet in a multimode mode-space model to show that the EP survives spectator modes. Eigenvalue coalescence, phase-rigidity collapse, linear EP tracking with residual detuning, and branch exchange under geometric encircling provide falsifiable signatures. An OAM-resolved input-output response maps these onto spectroscopy-level observables, including spectral maps and three-dimensional Riemann-surface visualizations. A device-level paraxial simulation of two distinct photonic platforms, one reciprocal and one asymmetric-coupling Wiersig-type platform, reproduces the predicted exceptional point and its linear geometric tracking.

Carbon nanotubes (CNTs) constitute a highly tunable platform for probing the interplay between structural chirality and quantum transport in quasi-one-dimensional systems. Here, we perform a systematic study of the non-equilibrium orbital response across a broad set of metallic and semiconducting chiral CNTs. We find that the orbital Edelstein susceptibility depends strongly on both chirality and nanotube diameter, revealing that the orbital response cannot be captured by a universal scaling law. Instead, distinct families of CNTs emerge, forming characteristic orbital-response branches uniquely determined by the chiral wrapping vector. We further investigate the role of metallic contacts on orbital-current generation and orbital selectivity. While metallic CNTs rapidly recover their intrinsic orbital response away from the contact region, semiconducting CNTs display pronounced oscillatory behavior arising from interference between transport channels carrying different angular momenta injected by wide-band metallic contacts. Finally, by incorporating angular correlations into the contact self-energy, we demonstrate that chiral CNTs can operate as efficient orbital-angular-momentum filters, selectively transmitting orbitally textured electronic states in accordance with the crystal angular momentum of the propagating bands.

Twisted van der Waals bilayers form moiré superlattices whose structural and vibrational properties are highly sensitive to variations in local stacking registry and the degree of atomic reconstruction, yet accurate atomistic modeling of these systems at the DFT level remains computationally prohibitive at small twist angles. We investigate machine-learned interatomic potentials for moiré systems, using twisted bilayer graphene, h-BN, and MoS$_2$ as representative materials spanning a broad spectrum of mechanical compliance and atomic reconstruction behavior. We show that fine-tuning universal atomistic foundation models is essential to achieve DFT accuracy for layered materials, as broadly trained foundation models prove insufficient for resolving the subtle interlayer energetics that govern atomic reconstruction. Through local strain tensor analysis and the phonon band unfolding technique, our fine-tuned MACE model reveals a consistent reconstruction-induced strain landscape in all three materials, with extended low-energy stacking domains separated by narrow soliton lines where deformation concentrates. The system progressively optimizes the local stacking registry within each domain, giving rise to a spatially structured deformation field whose amplitude scales with the mechanical compliance of the material and can be further tuned by external perturbation. The obtained results of both atomic reconstructed structures and moiré phonon spectra present a good agreement with the reported experiments, thereby demonstrating the accuracy and efficiency of our methodology in modeling of these large scale nanomaterials.

We present a non-Markovian open-quantum-system formalism for nonequilibrium electron-phonon dynamics: a closed set of five coupled equations of motion, derived directly from the density matrix, in which memory, dissipative broadening, and coherent-phonon dynamics arise on an equal footing without two-time correlators. It recovers the Fan-Migdal, RPA-polarization, and Ehrenfest self-energies and the Lindblad and Boltzmann limits. In the strongly driven Holstein dimer it separates the coherent polaronic peak, of Ehrenfest origin, from the linewidths and multiphonon structure of Fan-Migdal origin.

A microscopic description of nucleon-nucleon (NN) and nucleon-nucleus (NA) scattering is developed using chiral effective field theory (chiEFT) at next-to-next-to-next-to-leading order N3LO. The NN interaction is taken from the EGM formulation, which incorporates spectral function regularization Lambda-tilde to control short range components of the two pion exchange force, together with a Gaussian regulator Lambda to ensure convergence of the Lippmann-Schwinger (LS) equation. The regulator parameters (Lambda, Lambda-tilde) = (450, 500), (550, 600), (600, 600) MeV. The resulting chiEFT NN t-matrix is used to construct the first order optical potential, from which Wolfenstein amplitudes and elastic differential cross sections are calculated. The theoretical amplitudes (B) and (C) for pp and pn scattering at 100 and 200 MeV show good overall agreement with experimental data, with the largest discrepancies appearing in the small real component of the spin orbit amplitude. Calculations of p + 16O and p + 40Ca elastic scattering at 100 and 200 MeV reproduce the measured angular distributions with high accuracy, particularly at forward and intermediate angles. These results demonstrate that the EGM chiEFT potential provides a consistent and quantitatively reliable framework for describing NN observables and NA elastic scattering in the 100-200 MeV energy range, while highlighting the need for improved treatment of short range and spin dependent contributions at higher energies.

This paper investigates the rare decays of the Z boson into S-wave quarkonia within the Bethe-Salpeter formalism. Both the production of double S-wave quarkonia and radiative decays into single S-wave quarkonium are analyzed. For double quarkonia production, i.e., $Z\to VV$ and $Z\to VP$ (where $V$ and $P$ represent vector and pseudoscalar quarkonia, respectively), we consider the leading order contribution from both QCD as well as electromagnetic transition via virtual photon (QED) amplitudes. The heavy quark limit is adopted to simplify calculations. Additionally, we have introduced another possible leading order channel for Z-boson decays to double S-wave quarkonia, where the Z boson decays into bottomonium plus charmonium via QED amplitude. Such processes may include $Z\to J/\psi+\Upsilon(1S)$, $Z\to\eta_{b}+J/\psi$ and $Z\to\eta_{c}+\Upsilon(1S)$. Moreover, we have also studied radiative Z boson decays to S-wave quarkonium, namely $Z\to X(Q\bar{Q})\gamma$, where $X(Q\bar{Q})=J/\psi$, $\Upsilon$, $\eta_{c}$, and $\eta_{b}$. Interestingly, for double charmonium and radiative charmonium production, our results are larger than the NRQCD finding, while for the bottomonium case, our findings are comparatively smaller. This shows that charmonium is a relativistic particle, while bottomonium is a non-relativistic particle.