Papers

We investigate piezomagnetism in higher-spin altermagnets with easy-plane single-ion anisotropy using a flavor-wave approach. We show that quantum fluctuations of higher-spin collective modes provide a microscopic origin of the piezomagnetic response. For integer spins, the relevant branch softens and evolves into a Higgs-like amplitude mode on approaching the large-$D$ transition, endowing the excitation with a sizable dipolar component and producing a pronounced enhancement of piezomagnetism. By contrast, in half-integer systems the higher-spin branches are progressively separated from the low-energy dipolar sector as the anisotropy increases, which suppresses their contribution to the response. This integer-half-integer contrast directly links macroscopic piezomagnetism to the low-energy fate of multipolar excitations. Our results establish piezomagnetism as a probe of higher-spin quantum dynamics and identify higher-spin altermagnets as a promising setting for quantum magnetoelastic responses.

This thesis utilizes a multiscale method by connecting molecular dynamics (MD) based information to hydrodynamic macroscopic calculations for investigating the shock response and spallation of metals. First, shock propagation in Cu, Al, and Ni single crystals is simulated up to $100$ GPa at strain rates $>10^6$ s$^{-1}$. Shock-Hugoniot ($U_s$-$U_p$) relations agree strongly with experiments (error $<6\%$); the Foiles EAM potential shows the least deviation for Ni. Second, a multiscale framework linking MD atomic void kinetics to hydrodynamic macro-calculations is established. Using particle swarm optimization (PSO), Nucleation and Growth (NAG) parameters are extracted for Cu, Nb, Mo, and Al, yielding free surface velocity (FSV) profiles matching experiments within $8\%$ for Al. Third, deformation across ten Al tilt (STGB) and twist (STwGB) bicrystals at rates of $10^{10}$-$10^{11}$ s$^{-1}$ proves that threshold spallation depends on boundary misorientation. Phase transitions near GBs lower spall strength at high $U_p$, whereas GB plasticity prolongs pull-back and delays spallation (e.g., $14.2^\circ$ STwGB). FSV methods are found to underestimate true peak tensile strength. Fourth, the framework is extended to polycrystals via 11 STGB and 12 STwGB configurations. Voids consistently nucleate at weakened GBs. Unique NAG parameters are fitted using PSO for all 23 bicrystals. An Average Void Growth in a Fluid Element (AVGFE) model is introduced to map these distinct boundary properties into 1D hydrodynamic codes. The combined model is validated against empirical Al flyer impacts at $518$, $1588$, and $2275$ m/s. The simulated temporal FSV curves mirror experiments, with spall strength deviations tightly bounded within $2.15\%$, $2.9\%$, and $6.0\%$, respectively, and spall thickness deviations within $2.4$-$4.0\%$.

The final stages of outbursts in transient X-ray pulsars (XRPs), which are characterised by a significant decline in the mass accretion rate, provide valuable insight into the physics of the accretion disc and its interaction with the strong magnetic field of the neutron star (NS). In particular, the `propeller effect', or centrifugal inhibition of accretion, has been proposed as a key mechanism governing both the onset luminosity and the timescale of the rapid transition to the quiescent state. In addition, it offers an independent method for estimating the magnetic field strength of the NS. On the other hand, the decrease in the mass accretion rate itself is driven by processes occurring in the accretion flow at larger distances from the NS. Recovering the information encoded in the light curve therefore requires sensitive high-cadence X-ray monitoring capable of capturing the rapid and often unpredictable transition from the accreting regime to the quiescent regime. In this study, we present the results of the first comprehensive monitoring campaign that tracks the entire transition to quiescence in the transient XRP 4U 0115+63 utilising observations by the NICER X-ray telescope. We show that the observed behaviour can be explained by the thermal-viscous disc instability model (DIM), with the emission observed immediately after an outburst possibly arising from the ongoing accretion from the recombined (`cold') disc and the subsequent quiescent emission being produced by the cooling NS. We further applied this model to a larger sample of XRPs encompassing a broad range of physical parameters. Ultimately, our findings indicate that the temporal behaviour of XRPs, including the quiescent state, can be consistently explained within the DIM framework without requiring the propeller effect as the primary mechanism governing the observed transition.

This work presents the design of a Linear Quadratic Regulator for relative motion control near periodic orbits in the Circular Restricted Three-Body Problem (CR3BP), formulated in non-singular toroidal coordinates. The key result exploits the rotational quasi-periodicity of the toroidal coordinate transformation. A uniqueness argument on the stabilizing solution of the associated difference Riccati equation proves the optimal control gains need only be computed for a single orbital period. The controller is validated against the full non-linear CR3BP dynamics on an L1 Northern halo orbit in the Earth-Moon system, and further against a high-fidelity ephemeris model, demonstrating successful reconfiguration maneuvers on the invariant torus with low control effort. Compared with an impulsive targeting and station-keeping baseline, the proposed controller attains a comparable tracking accuracy while reducing the total control effort by approximately 40%.

These lecture notes provide an introduction to Bose-Einstein condensates with Raman-induced spin-orbit coupling. Owing to the interplay between the peculiar single-particle dispersion, featuring a double-minimum structure, and the two-body interaction, these systems possess a complex phase diagram. Three different quantum phases can be observed, i.e., a stripe, a plane-wave, and a single-minimum phase, each characterized by different broken symmetries. The condensate dynamics is also significantly affected by the spin-orbit coupling, as revealed by the behavior of the Bogoliubov spectrum in infinite systems and the behavior of the discretized collective mode frequencies in trapped configurations, especially close to the phase transitions. In turn, the superfluid and rotational properties are also deeply modified by the coupling between the motional and spin degree of freedom. Finally, a special attention is devoted to the stripe phase and its supersolid character, which can be clearly revealed by the study of its dynamic features.

Cathodoluminescence (CL) spectroscopy provides access to optical excitations with nanometer spatial resolution, but direct time-resolved measurements of optical resonances remain challenging. Here, we demonstrate that CL interferometry provides access to the temporal response, phase behavior, and modal spectral structure of resonant nanoscale scatterers without requiring ultrafast pump-probe schemes. We develop an analytical framework in which Fourier transformation angle- and frequency-resolved CL interferograms yields the decay time of optical resonances governed by the linear optical response. Multimode resonators exhibit characteristic temporal CL beating signatures associated with spectral mode splitting. By exploiting transition radiation emitted from a nearby metallic surface as a broadband reference, we further demonstrate phase retrieval and cross-correlation measurements between instantaneous and resonant emission processes. Experimental measurements on Au nanoparticles, broadband plasmonic emitters, Au nanostars, and Si nanospheres supporting multipolar Mie resonances confirm the theoretical predictions, and decay times in the range 1-10 fs are derived for each system. Our results establish CL interferometry as a powerful approach for accessing spectral, spatial, and phase information within a single nanoscale measurement with fs resolution.

Intermediate-mass black holes are widely considered to be the seeds of supermassive black holes, a substantial population of which is expected to remain displaced from galactic nuclei owing to hierarchical galaxy assembly and inefficient dynamical friction. While several fueling channels can sustain central black holes, those pathways are largely inaccessible to off-nuclear black holes, leaving their fuel supply uncertain. As these wandering black holes move through the interstellar medium of their host galaxies, theory predicts that they can capture gas from the dense wake produced by gravitational focusing. However, direct observational evidence for this process has remained elusive. Here we report evidence for a wandering intermediate-mass black hole of 35,000 solar mass accreting through such a gravitational wake. Its black-hole nature is supported by broad-line emission, a compact continuum counterpart, long-term optical variability, and a power-law-like spectral energy distribution. Multi-epoch spectroscopy reveals three distinct gas components: a blueshifted, low-density upstream flow; a redshifted, dense downstream wake; and optically thick absorbers well within the capture radius that drive rapid changing-look variability in the broad-line emission. This discovery establishes a previously unobserved channel for the growth of wandering intermediate-mass black holes.

We investigate the geometrical and thermodynamical aspects of particle production in pp collisions over a broad center-of-mass energy, ranging from $\sqrt{s}=62.4$ GeV to 13 TeV using PYTHIA8. We study the azimuthal dependence of charged-particle production relative to the leading particle. This includes the study of the Tsallis–Pareto parameters extracted from the charged-particle transverse-momentum spectra in fixed $\Delta\phi$ intervals relative to the leading charged particle. The simultaneous analysis of charged-particle multiplicity and event topology demonstrates that the underlying event (UE) dominated region can be extended beyond the conventional transverse side region across RHIC and LHC energies. To further disentangle effects from soft and hard particle production mechanisms, the study is performed in different transverse spherocity and charged-particle flattenicity classes. We demonstrate that the UE region extends beyond the conventional transverse region, validating an enlarged angular interval of $40^\circ\lesssim|\Delta\phi|\lesssim140^\circ$ from RHIC to LHC energies. Event-shape selections reveal that jetty events consistently exhibit larger $q$ and lower $T_{\rm s}$ than isotropic events. The $\Delta\phi$ profiles of charged-particle multiplicity and transverse spherocity remain universal in shape across collision energies despite the strong increase in overall event activity, whereas the Tsallis parameters retain a residual, leading-particle-driven energy dependence in the near- and away-side regions.

Atmospheric escape is considered a key process in shaping exoplanet demographics and evolution. The near-infrared metastable helium triplet (HeI at ~10833Å) is one of the most powerful tracers of hydrodynamical outflows. In recent years, a large variety of instruments have been used to detect and characterize expanding upper atmospheres. High-resolution (HR) spectrographs, which can spectrally resolve the lines of the triplet, have been mostly used to probe the dynamics of atmospheric escape. More recently, JWST (low-resolution, LR) detected extended outflows that were missed by previous ground-based observations due to night-length constraints. Since the observed transmission spectrum is computed from the ratio of stellar spectra degraded by instrumental convolution, we demonstrate that directly convolving a theoretical transmission spectrum with the instrument's profile leads to inference biases as resolution decreases. This conclusion is particularly important for atmospheric escape studies but also holds in the more general context of LR atmospheric retrievals. Following the proper comparison methodology, we then investigated the complementarity of HR and LR observations for atmospheric escape measurements, comparing the capability of three instruments (NIRPS, JWST/NIRSpec, and JWST/NIRISS) to detect and characterize outflows. We find that NIRPS and JWST/NIRISS are mostly sensitive to the same helium signatures, while JWST/NIRSpec improves the detection limit of excess absorption for faint targets. Studying different outflow configurations, we show that LR space-based measurements cannot be used to infer the dynamics of the upper atmosphere close to the planet, and are best employed to measure the spatial extent of outflowing tails. We thus highlight the complementarity between HR and LR observations of atmospheric escape, the latter improving baseline reconstruction.

Let $\mathcal{T}_{n,m} = \mathcal T_n(M_m(\mathbb{C}))$ denote the operator system of all block Toeplitz matrices $ T = (( T_{i-j}))_{i,j=1}^n$ with entries $T_k \in M_m(\mathbb C) $ % T_{k} = \left[ t^{(k)}_{p-q} \right]_{p,q=1}^m. \[ T = \begin{pmatrix} T_0 & T_{-1} & \cdots & T_{-(n-1)} T_1 & T_0 & \cdots & T_{-(n-2)} \vdots & \vdots & \ddots & \vdots T_{n-1} & T_{n-2}& \cdots & T_0 \end{pmatrix} \in M_{mn}(\mathbb{C}). \] We characterize all pure unital completely positive ({\it{ucp}}) maps from $\mathcal{T}_{n,m}$ to $M_m(\mathbb{C})$. Working through the Stinespring isometry $V = (V_1, \ldots, V_n)^t \colon \mathbb{C}^m \to \mathbb{C}^{mn}$ and the matrix-valued polynomial $Q_V(z) = \sum_{i=1}^n z^{n-i} V_i$, we prove that $\varphi$ is pure if and only if it admits a unique pure \ucp extension to $M_{mn}(\mathbb{C})$ if and only if $Q_V$ has degree $n-1$ with all its roots on the unit circle $\T$. Every such pure $\varphi$ induces a \ucp map $\Phi_{Q_V}$ on $C(\mathbb{T}, M_m(\mathbb{C}))$ given by \[ \Phi_{Q_V}(f) = \int_{\mathbb{T}} Q_V(z)^* f(z) Q_V(z)\, dz. \] Let $\mathcal{Y}_m$ be the compact convex set of all \ucp maps from $C(\mathbb{T}, M_m(\mathbb{C}))$ to $M_m(\mathbb{C})$. Endowing $\mathcal{Y}_m$ with the matricial Monge-Kantorovich metric $\rho$, via an analysis of the extreme points of $\mathcal{Y}_m$ together with a point-splitting lemma, we show that the induced maps as above are $\rho$-dense in $\mathcal{Y}_m$. Consequently, if $\Bmn$ denotes the set of normalized $\Phi_{Q_V}$ where $Q_V$ is as above, then the Hausdorff distance $d_H(\Bmn, \mathcal{Y}_m) \to 0$ as $n \to \infty$, extending known results of approximation of positive regular Borel measures on the unit circle to the setting of matrix-valued completely positive maps.

We identify the spin rotatory strength—a chirality-odd, finite-frequency spin–dipole cross response—as the equilibrium observable for chiral-induced spin selectivity. Time-reversal symmetry forces the static response to vanish, while nonzero SU(2) Wilson-loop flux is an independent necessary condition. Exact diagonalization of a Kane–Mele–Hubbard model ($N{=}4,6,8$) reveals that gapped molecules robustly suppress the response, whereas near-degenerate systems show amplification at small $N$ whose persistence at larger sizes remains open.

Two alternative approaches for studying Helium-like atomic ions in non-relativistic quantum mechanics are proposed: (I) a numerical approach, based on the Lagrange-mesh method which can easily reach up to 14-15 significant digits in the energy spectrum for any nuclear charge $Z$ with modest CPU time in single processor mode and (II) a highly-accurate, few-parametric interpolation formula for the energies vs. $Z$. The interpolation formula of general nature is proposed, it can be applied to the energies of any excited state of the helium-like sequence. It is based on matching the $1/Z$-expansion at large $Z$ and the Puiseux expansion with integer and half-integer powers around the so-called second critical charge $Z_B$, introduced by F and D Stillinger (1969, 1974), confirmed by the present authors in 2019 for the ground state $1^1 S$, then revisited here, and extended to the excited states in the present work. For example for the first two spin-singlet $1^1 S$, $2^1 S$ and the first two spin-triplet $2^3 S$, $3^3 S$ states this interpolation formula with nine free parameters can reach an accuracy of 10-14 significant digits (s.d.) in the energies for any physically-relevant nuclear charge $Z$, giving absolute accuracy at large $Z$. Many results are obtained for the first time.

Degradation in lead halide perovskite solar cells is analysed by inverse modelling of published measurements of characteristics of a single solar cell at ages 0, 90, 280, 480 minutes. We employ machine learning to deduce distributions of material parameter values and hence the physics linked to measured changes. Bayesian parameter estimation is coupled with drift diffusion simulations using the IonMonger code combined with an optical model. We accurately replicated measured changes in device performance with age through variations in model input parameters. Our key result is that degradation is influenced by correlated changes in the concentrations and diffusion coefficients of mobile ions and by interface recombination at large mobile ion concentrations. This study demonstrates the power of machine learning combined with simulations to reliably interpret experimental results, a task which is problematic if using simulation models with only manual exploration of the input parameter space.

Reflection positivity is one of the Osterwalder–Schrader axioms for Euclidean quantum field theory, ensuring that the reconstructed relativistic Hilbert space carries a positive-definite inner product. For free fermionic theories whose covariance is a real rational function of the Dirac operator, we prove that reflection positivity holds if and only if all poles are real, simple, and carry non-negative residues. We also explicitly show the failure of reflection positivity for covariances with exponential regulators.

Modal dynamics in multimode optical fibers are fundamentally governed by the inter- play between phase matching and intermodal coupling. In this work, we investigate the fundamental coupling mechanisms in ring-core fibers and identify a geometry-induced cou- pling suppression that significantly reduces coupling coefficients between orbital angular momentum modes compared to conventional multimode step-index fibers. This mechanism provides a clear physical explanation for the superior transmission stability of orbital angular momentum modes in ring-core fibers and establishes specific geometric constraints for the design of ring-core fiber-based mode converters.

The Uhlmann fidelity ${\rm F}(\rho_0,\rho_1) = {\rm tr}|\sqrt{\rho_0}\sqrt{\rho_1}|$ is one of the most fundamental quantities in quantum information theory for quantifying the closeness between two quantum states. Estimating the Uhlmann fidelity to within additive error $\varepsilon$ requires a number of copies of the states, or queries to their state-preparation circuits, that depends at least linearly on the smaller of the ranks of $\rho_0$ and $\rho_1$. Consequently, this rank dependence disappears when either state is pure, in which case the query and sample complexities depend only polynomially on $1/\varepsilon$. However, the known optimal estimator for ${\rm F}(\rho,|\psi\rangle\!\langle\psi|)$ due to Fang and Wang (ESA 2025) requires prior knowledge of which state is pure. In this work, we remove this mathematically unnecessary prior-knowledge requirement and establish an optimal estimator for ${\rm F}(\rho, |\psi\rangle\!\langle\psi|)$ under the sole promise that one of the two states is pure, without knowing which one. Our estimator is obtained by specializing the refined algorithmic Uhlmann transform of Utsumi, Nakata, Wang, and Takagi (2025) to the case where one state is pure. In this setting, the Uhlmann fidelity can be recovered as follows: apply a unitary dilation of ${\rm tr}_{\sf A}(|\psi_0\rangle\!\langle\psi_1|)$ (or its inverse) to the reference register $\sf R$ of the purification $|\psi_1\rangle$ (or $|\psi_0\rangle$) on the registers $\sf A$ and $\sf R$, estimate the corresponding square-root amplitude in each case, and take the maximum of the resulting two estimates.

Compton cameras are proposed for tasks whose value decays with delay: verifying a range during irradiation, guiding an intervention, characterising an inaccessible volume, surveying a band no telescope covers. Whether a device can serve such a task is settled by the composition of its whole chain, while the literature that would answer the question is organised by stage – so claims made at application level routinely rest on evidence obtained at component level. This review walks that chain, asking at each stage what binds first and what a reader can determine from the published text, and then asks what governs whether a capability transfers between groups and between application domains. The evidence is of two kinds: 83 full texts scored in context against defined markers, and, for five application domains measured alike, the size of the receiving literature, of the need it states, of the incumbent and of deployment commitment. Performance is reported at one operating point in 65 of 83 full texts, with count rate swept in none: the field reports values where transfer requires gradients. An accelerator is used in 39 works and a learned model in 31, while separability is discussed in 28, a memory footprint given in 9, and the cost of a precomputation or the inference time of a model in none. Across domains, neither the size of the receiving literature, nor of the incumbent, nor of the stated need orders the domains as deployment commitment does, while whether the incumbent can serve the task at all, and how many domain boundaries the output must cross, do so consistently. The distribution of publication is close to the inverse of the distribution of deployment commitment. We give the quantities a report must contain for a third party to judge whether a method fits an application it was not built for.

Computational electromagnetics plays a central role in many industrial applications but often requires substantial computational resources, particularly when fine spatial discretizations are needed. While classical approaches remain the standard, quantum computing offers the potential to accelerate large-scale simulations by encoding them with a limited number of qubits. Here, we investigate the performance and resource scaling of the Harrow-Hassidim-Lloyd (HHL) and Quantum Singular Value Transformation (QSVT) algorithms for solving linear systems generated by the finite-difference time-domain (FDTD) method, a widely adopted numerical scheme for discretizing Maxwell's equations. We benchmark their performance across representative industrial use cases, including radar propagation, lens simulations, and beamforming processes. Our results demonstrate the validity of the approaches, achieving state infidelities smaller than $2\cdot 10^{-3}$ with success probabilities greater than $10^{-3}$, compatible with practical quantum state sampling. Overall, we observe that the QSVT method consistently delivers higher accuracy. We further observe that the condition number of the linear matrix, a key factor governing the performance of quantum solvers, saturates as the number of spatial lattice points increases. This implies that the spatial grid can be scaled to realistic industrial dimensions without increasing the HHL or QSVT circuit depth due to ill-conditioned matrices.

We introduce a systematic framework for constructing spacetime and D-brane effective actions in bosonic string theory, encompassing both tachyon and massless modes. The actions are required to be gauge invariant and compatible with the expansion of sphere- and disk-level S-matrix elements. Our central proposal stipulates that, for each closed- or open-string channel, S-matrix poles involving an odd number of tachyons must be reproduced via an expansion in the effective action, whereas those with an even number of tachyons must be matched exactly. This criterion imposes strong selection rules: the bulk action contains only even powers of closed-string tachyon fields, and the D-brane action only even powers of open-string tachyon fields. In contrast, couplings of closed-string tachyons to D-branes are less constrained and allow both even and odd field multiplicities. As a concrete application, we analyze the disk-level amplitude involving two closed-string tachyons and demonstrate that the resulting linear and quadratic tachyon-D-brane interactions coincide precisely with those of type 0 theory. This is consistent with the duality between the orbifold of type 0 theory and the compactification of bosonic string theory on \(T^{16}\).

Understanding how complex connectivity emerges in networks is a fundamental challenge in classical and quantum science. In classical random networks, complex subgraphs typically require relatively high connection probabilities, whereas quantum random network theory predicts that such structures can arise at a single, lower threshold through entanglement and local operations. Here, using an integrated silicon photonic chip, we experimentally realize a quantum subgraph predicted by quantum random network theory in a four-node quantum random network. Our integrated platform exploits probabilistic photon-pair sources and coherent control of path modes to prepare a structured quantum subgraph through local transformations and postselection, operating in a threshold regime that differs from classical random networks. We verify that the subgraph state exhibits genuine high-dimensional multipartite entanglement across the nodes, providing experimental evidence that quantum entanglement enables connectivity structures beyond classical accessibility.

We introduce a new singular-value-decomposition-based scheme for constructing small virtual spaces out of large basis sets for transcorrelated (TC) calculations, termed SVD-TC. This work builds on the recent finding that the residual basis error in the TC reference energy converges more slowly than that of the correlation energy. Within the new workflow, the post Hartree-Fock TC calculation is performed in a compressed virtual orbital subspace, obtained by projecting the canonical virtual orbitals from a large basis set onto a smaller basis set through singular value decomposition (SVD). This allows us to achieve the high accuracy allowed by the large basis, whilst the bottleneck steps - TC integral calculation and post-HF correlation method such as CCSD(T) - incur the cost of only a small virtual space calculation. The method therefore is highly efficient, whilst avoiding the composite nature of the reference correction method. Using the new scheme, we widen the scope of benchmark-quality TC results into more complex molecules than previously considered: using the G2-1 set of 55 molecules with first- and second-row atoms, we apply SVD-xTC-CCSD(T) to compute atomization energies. We compare our results against the near-exact semistochastic heat-bath configuration interaction (SHCI) reference values and experiment. We find that SVD-xTC-CCSD(T) delivers chemical accuracy already with triple-$\zeta$ basis sets. Finally, we use the quadruple-$\zeta$ results to analyze the accuracy of pseudopotentials within the TC method, and show that pseudopotential TC workflow provides faster basis-set convergence than all-electron TC. We also present timings for computing the atomization energies on G2-1 set, demonstrating the efficiency of our TC workflows.

Quadruply bonded Mo2 complexes provide a distinctive molecular platform in which multiple two-level electronic transitions interact with quantized scattering modes under ambient conditions. Here we show that, in the Mo2 complexes, the intrinsic photonic modes selectively couple to molecular excitations, including the characteristic delta-delta(star), ligand to metal charge transfer (LMCT) and metal to ligand charge transfer (MLCT) transitions, to form the well-resolved exciton-photon hybrid states. By combining steady-state absorption, resonance fluorescence, and ultrafast transient spectroscopies, we identify distinct polaritonic branches associated with these electronic manifolds, with coupling strengths spanning the strong and ultrastrong regimes (g/omega0 up to 0.1). Mode-selective coupling accounts for the pronounced spectral reorganization for the singly oxidized complexes, including the emergence of absorption valleys and sidebands of the associated resonances in the steady-state spectra, characteristic polaritonic emissions in the photoluminescence spectra, and long-lived low-energy hybrid states in the transient spectra. These results support the picture that the Mo2 unit functions as an integrated molecular resonator whose intrinsic quantized field selectively drives and redistributes molecular excitations. This work strengthens the emerging view of bonded dimetal complexes as ambient-condition molecular quantum systems and provides a chemically defined platform for exploring polaritonic chemistry.

In this paper, we investigate zero transfer on mixed graphs. Zero transfer is a quantum walk phenomenon in which the transition amplitude between two vertices is identically zero for all times, so that no quantum state transfer occurs between them. Using the Hermitian adjacency matrix, we derive necessary and sufficient conditions for zero transfer in mixed graphs. We then specialize these criteria to oriented circulant graphs, obtaining nonexistence results for prime order, structural restrictions for even order, and exhaustive computational classifications for small orders.

In this work, we investigate the excitation dynamics of a Rabi-coupled dissipative Rydberg lattice with a time-dependent detuning. The system is analyzed using (i) a Lindblad master equation within a mean-field approximation and (ii) an effective non-Hermitian Hamiltonian framework. While the mean-field approach captures the emergence of an antiferromagnetic order in the Rydberg excitation profile, the non-Hermitian description provides direct insight into the complex energy spectrum and its avoided crossings, which govern the Landau$-$Zener dynamics. We identify a regime in which the sublattice population imbalance vanishes near the avoided crossing, resulting in identical Landau$-$Zener probabilities on the two sublattices. Beyond a critical effective blockade strength there is a dynamical crossover to another regime in which the sublattice population imbalance persists through the avoided crossing, giving rise to sublattice-dependent Landau$-$Zener probabilities. Furthermore, Rydberg interactions prolong the lifetime of Landau$-$Zener-induced excitations in the presence of weak dissipation and strong Rabi coupling. In contrast, for weak Rabi coupling, the Rydberg blockade inhibits excitation and suppresses the Landau$-$Zener transition probability.

We investigate the infrared magneto-optical response of n-doped epitaxial graphene on 4H-SiC in ultrahigh magnetic fields up to 560~T, utilizing single-turn coil and electromagnetic flux compression techniques. The measured absorption spectra are anomalously broad, strongly deviating from conventional cyclotron resonance. Angle-resolved photoemission spectroscopy (ARPES) reveals a distorted Dirac dispersion featuring a “camel-back" structure with an energy gap of $E_g \sim 0.2$~eV. Using the band parameters extracted via a generalized bilayer graphene model, we construct a Landau level (LL) fan chart that dictates a critical level crossing between the $N=0^+$ and $N=0^-$ states near 160–200~T. At this threshold, the optical transition mechanism undergoes a dramatic shift from an electron-dominated collective mode to a cooperative electron-hole collective excitation. Furthermore, the extreme-field absorption spectra under thulium fiber laser excitation ($\hbar\omega_0 = 0.636$~eV)—culminating in a massive resonance near 400~T with a shoulder at 200~T—are excellently reproduced by a collective Alfvén wave model. This analysis also evidences a magnetic-field-induced enhancement of the sublattice potential asymmetry parameter (from 0.10~eV to 0.12~eV). This directly signifies that the macroscopic electron-hole band asymmetry is further amplified by the applied magnetic field. Ultimately, the field-induced energy inversion generates a strongly interacting, fully compensated electron-hole plasma. The resonant excitation of Alfvén waves in this regime demonstrates that a pristine tabletop analog to the relativistic electron-positron plasmas found in astrophysical extremes can be elegantly realized within a 2D graphene system.

We discuss a mechanism for generating the baryon asymmetry in the early universe. We show that an axion-like particle can modify the related gauge field configurations in the Standard Model, thereby altering their dispersion relations. This change in the Chern-Simons number can source a violation of baryon number. We derive the relationship between the resulting baryon number and the evolution of the axion background. We estimate the baryon asymmetry produced via this mechanism and show that the observed value can be naturally achieved. We also show that axion photon coupling produces Cosmic Microwave Background spectral distortion. Our results show that the resulting distortion approaches a constant at low frequencies, unlike the conventional y-type and $\mu$-type distortions.

Group-IV color centers, such as the silicon-vacancy (SiV) defect, are highly promising for solid-state quantum technologies. However, nanodiamonds typically exhibit significant lattice strain and structural disorder, which degrade their optical properties and hinder the resolution of the fine spectral structure at cryogenic temperatures. High-pressure high-temperature (HPHT) annealing offers a potential route to relax internal strain, although the phase stability of diamond at the nanoscale under such conditions remains poorly constrained. Here, we investigate the structural evolution of nanodiamonds during HPHT annealing using a Paris-Edinburgh press coupled with in situ synchrotron X-ray diffraction at SOLEIL. A dedicated sample assembly combining nanodiamonds - NaCl - Pt enabled accurate pressure-temperature calibration and real-time monitoring of phase transformations. The diffraction data reveal that the onset of diamond-to-graphite transition occurs at approximately 1800 K at 2 GPa and 2120 K at 4 GPa under the applied HPHT heating protocol. These experimentally determined graphitization onsets define a practical pressure-temperature processing window for HPHT annealing of nanodiamonds while avoiding detectable graphitization and provide a calibrated framework for reliable off-beam annealing treatments that avoid graphitization. Photoluminescence measurements on samples annealed below the graphitization threshold show improved optical response, with partial resolution of the SiV fine structure at 12 K. These optical measurements suggest a relationship between nanoscale phase stability and the optical response of individual SiV-containing nanodiamonds following HPHT annealing. The experimentally established HPHT processing window provides a practical framework for the controlled processing of quantum nanodiamonds while avoiding graphitization.

Slow cyclic modulation of an open quantum system can generate a geometric contribution to its energy transfer statistics, separable from the dynamic background. In this work we construct an experimentally anchored four state open system model for a gate-tunable WSe2/WS2 moiré exciton manifold within a population level full counting statistics framework. We first drive the system uniformly through a closed gate and pump loop and separate the geometric contribution from the dynamic background by reversing the loop direction. We then examine how this response changes with environmental rates, exciton coupling, control conditions, and static spectral broadening. A shorter cycle period followed by nonuniform traversal of the driving loop substantially improves detectability while preserving the geometric response. Combined with enhanced phonon relaxation and reduced radiative loss, this gives about a fourteenfold fixed time signal to noise gain relative to the uniform loop. Our results show that the geometric phonon response remains robust against realistic variations in the system and its environment, and that we can improve its detectability more effectively by suppressing dynamical noise through frequency modulated driving.

Uncertainty in wind farm layout optimization regarding model choice and the impact of global blockage always exists. This paper evaluates these interactions by extending a multi-objective approach that maximizes mean Annual Energy Production (AEP) from a model ensemble while minimizing their variance. By incorporating the Self Similar blockage model into an ensemble of five wake models, we assess the impact of blockage physics on layout robustness. Results from a linear mixed-effects model indicate that including blockage leads to a non-significant average AEP reduction of 0.0624 GWh ($p$-value = 0.323). Conversely, it caused a highly statistically significant increase in uncertainty, with model disagreement rising by 0.177 GWh ($p$-value < 0.001). Additionally, computational runtime increased nearly nine times. These findings highlight an accuracy vs. certainty paradox, where theoretically necessary physics can compromise model consensus if implemented without re-calibration. Ultimately, this work suggests that simple blockage couplings act as a diagnostic for model incompatibility, emphasizing the necessity of careful model tuning for wind farm design.

We prove asymptotic stability of the degree-one vortex in the $(1+2)$-dimensional abelian Yang-Mills-Higgs model at the self-dual coupling, for small equivariant perturbations in weighted Sobolev spaces. The abelian Yang-Mills-Higgs model is a classical relativistic field theory on $(1+2)$-dimensional Minkowski space, describing a complex-valued field coupled to an electromagnetic potential and admitting topological solitons known as vortices. This paper is the final and main part of a three-paper series. Under the orthogonal gauge condition used here, perturbations of the vortex are governed by a system of nonlinear Klein-Gordon equations for the dynamical variables, coupled to an elliptic equation for the temporal component of the electromagnetic potential. The linearized operator has continuous spectrum $[1,\infty)$ and a single positive gap eigenvalue (internal mode) of multiplicity two, whose spectral properties, associated distorted Fourier theory, and linear decay estimates are developed in the two companion papers. The main difficulty is the long-time analysis of the coupled radiation–internal-mode dynamics. In two space dimensions the dispersive decay of the Klein-Gordon radiation is relatively weak, while the internal mode decays only on the long time scale dictated by nonlinear radiation damping. At the same time, the Klein-Gordon equations for the radiation contain non-spatially localized variable coefficient quadratic interactions, which cannot be treated perturbatively and require a normal form analysis. We prove decay of the radiation by combining a good-bad decomposition, a flat-sharp decomposition, and a space-time resonance analysis carried out relative to the flat Klein-Gordon flow. The passage between the flat analysis and the Klein-Gordon flow with potential is achieved through ILED and transference estimates derived from the distorted Fourier theory.