Parity-violating weak interactions produce extremely small energy differences between left- and right-handed chiral systems. We show that these microscopic effects may be amplified during collective phenomena such as phase transitions. The enhancement factor is proportional to the critical number of atoms, $N_c$, in the nucleus of the new phase. Measurement of the ratio of produced left- and right-handed chiral structures may provide a way to determine $N_c$. Experiments in which spin-chiral structures are formed in ${\mathrm{ZnCr}}_2{\mathrm{Se}}_4$ during a phase transition in crossed electric and magnetic fields indicate an effective amplification corresponding to $N_c\sim {10}^9–{10}^{10}$. We emphasize, however, that such large values cannot be inferred from homogeneous capillary nucleation alone, since the same parameters imply a very large nucleation barrier; in real crystals heterogeneous nucleation, defects, strain, and domain-growth dynamics may be essential. We also discuss, more cautiously, whether analogous collective enhancement could operate in first-order cosmological phase transitions beyond the standard model. The standard-model electroweak transition for the observed Higgs mass is a crossover and therefore has no critical bubble nucleus.

The Dicke-Hubbard model, describing an ensemble of interacting atoms in a cavity, provides a rich platform for exploring collective quantum phenomena. However, its potential for quantum thermodynamic applications remains largely uncharted. In this paper, a close connection between superradiance phase transition and the quantum thermodynamic applications of the Dicke-Hubbard model is established. Based on studies of the steady-state superradiant phase transition in the Dicke-Hubbard model and the thermodynamic mode of an Otto cycle with the Dicke-Hubbard model as the working substance, it is demonstrated that the steady-state synergistic mechanism under high- and low-temperature environments is the reason for the emergence of high-performance heat engines, while the competitive mechanism leads to the appearance of high-performance quantum refrigerators. A comparison of the thermodynamic behaviors of the Otto cycle with the Dicke model and the Dicke-Hubbard model as working substances reveals that the multicavity-coupled Dicke-Hubbard model achieves a higher coefficient of performance. These results not only deepen our understanding of the energy conversion mechanism in nonequilibrium quantum thermodynamics but also lay a theoretical foundation for the future experimental design of high-performance quantum Otto heat engines and refrigerators.

In this work, we report a sol-gel-based combustion process for the formulation of gallium oxide ($\beta \text{−}\mathrm{G}{\mathrm{a}}_2{\mathrm{O}}_3$) to develop robust UV-C (200–280 nm) photodetectors. Controlled Zn incorporation is employed to modulate the optical and electronic properties of $\beta \text{−}\mathrm{G}{\mathrm{a}}_2{\mathrm{O}}_3$. The devices are fabricated on a $c$-plane sapphire (0001) substrate, and a comparative analysis is performed for varying Zn dopant concentrations. Planar metal-semiconductor-metal structures with 50-µm-wide interdigitated aluminum electrode architecture are realized using standard photolithographic and processing techniques. The optimized photodetector devices exhibit a high responsivity, low rise time, and high photocurrent/dark current ratio of $\sim 20$ mA/W, $\sim 2$ s, and $\sim {10}^4$ in the UV-C range, associated with Zn-dependent modification of the material’s optical response, local electronic environment, and carrier transport/trapping processes. It establishes the Zn-doped $\beta \text{−}\mathrm{G}{\mathrm{a}}_2{\mathrm{O}}_3$ as a promising platform for robust, low-cost, and high-performance solar-blind UV-C photodetector applications.

We argue that the static dielectric constant of small (thin and/or narrow) semiconductor and insulator nanostructures depends strongly on their environment. We do so by considering the electronic response, simply reviewing, briefly but critically, the existing literature. Regarding the ionic response, in addition to reviewing the literature, we use a simple model to account for the confinement of optical phonons in thin films and show that the reduction of their density of states has a negligible effect on the dielectric constant, in contrast to some claims found in the literature. In general, we argue that in realistic structures, such as double-gated Si nanosheets, the use of the bulk dielectric constants for both the channel and the gate insulators is justified.

Quantum communication protocols based on spin chains have been extensively studied, yet their ability to transmit nonstabilizer resources has not been systematically addressed. We investigate the transport of quantum magic in spin chains through the natural dynamics of systems initialized in nonstabilizer states, and quantify the transported resource via the stabilizer norm. We analyze three experimentally feasible state-transfer protocols, ranging from noisy to (quasi)perfect transfer, including one realizable in trapped-ion platforms. We find that the geometry of the injected state strongly influences transport: States in the lower Bloch hemisphere achieve higher transfer quality, whereas states in the upper hemisphere give rise to an efficient magic transport only beyond a threshold value of the parameter controlling the tendency toward perfect transfer. These features are robust across all protocols and identify the Hamiltonian and state properties that favor high-quality transfer. Moreover, we identify a parameter region, relevant to the initial state preparation, in which the transported magic exceeds the initial encoding, indicating that such spin systems can act as magic-amplification channels. Our results establish the conditions for efficient transport of nonstabilizer resources and demonstrate quantum magic as a sensitive probe of quantum transport beyond population dynamics.

We present a framework based on the determinantal geometry of two-qubit gates. Combining the Weyl chamber representation with operator Schmidt theory, we interpret gate synthesis as a distance problem to determinantal varieties. This gives an operational geometry to the Weyl chamber, quantifying nonlocal complexity. We show that the $\sqrt{i\text{swap}}$ gate is the closest perfect entangler to the variety of local operations, and that no perfect entangler can be approximated by a local gate with average gate fidelity above $78.3\%$. The three different determinantal costs form a synthesis-adapted coordinate system that encodes nonlocal complexity and generally reconstruct the Weyl coordinates in the reduced sector.

We report that topological features of the dynamic electron density provide a microscopic electronic order parameter that directly reflects the extent of structural change during a phase transition and offers insight into its underlying mechanism. Using multipole electron-density models derived from extensive high-resolution synchrotron x-ray diffraction datasets collected on $\alpha \text{−}\mathrm{KN}{\mathrm{O}}_3$ at 100, 200, 290, and 380 K, we reconstruct the thermally convoluted dynamic electron density at each temperature. It is found that its temperature evolution quantitatively captures the progressive suppression of local symmetry breaking as the system approaches the $\alpha \to \beta$ phase transition. The topological descriptors of the electron density associated with the nitrate group exhibit a nonmonotonic temperature evolution with the initial inequivalence among the N–O bond electron densities undergoing an order-parameter-like collapse upon heating to 380 K, preceding the actual phase-transition temperature. These findings demonstrate that dynamic electron-density topology can provide valuable microscopic insight into structural phase transitions.

We investigate an extension of Harada gravity, a third-order theory proposed as an alternative to general relativity that preserves energy-momentum conservation and in which the cosmological constant arises as an integration constant. Our aim is to determine whether Harada gravity is unique under the principles that motivated its construction. We show that imposing both the existence of all Einstein solutions and energy-momentum conservation restricts the theory to only two distinct branches: general relativity and Harada gravity. We then relax each of these assumptions independently and demonstrate that, within the class of symmetric theories considered, Harada gravity remains the unique extension of general relativity.

Here, we present a detailed many-body ab initio study of the ${\mathrm{RbTlCl}}_3$ perovskite. The electronic and optical properties, both with and without spin-orbit coupling, have been calculated using density functional theory and many-body excited-state calculations. The band gap, which are indirect in nature, are found to be of 0.94 and 0.95 eV from Perdew, Burke, and Ernzerhof-based generalized gradient approximation exchange correlation functional with and without spin-orbit coupling, respectively. The optical properties have been computed using methods based on independent-particle approximation (IPA), IPA with scissor correction [independent quasiparticle approximation (IQPA)], local-field effects (LFEs) at random phase approximation level, and the Bethe-Salpeter equation (BSE). The estimated highest value of the imaginary part of the dielectric function using IQPA is $\sim 7$ at 2 eV, which slightly decreases to $\sim 5.7$ due to LFEs. Within the BSE, the peak value is obtained to be maximum at 1.6 eV with a magnitude of $\sim 10.8$, which indicates the strong excitonic effect below the scissor-corrected direct gap. A large number of bright and dark bound excitons are found, where the binding energies of four main bound bright excitons are found to be in the range of 315–365 meV. The main bound bright exciton is localized (delocalized) in the reciprocal (real) space. Also, the spectroscopic limited maximum photovoltaic efficiency is estimated to be 15.4% for a 0.5 µm thin film. Finally, the positive phonon frequencies and thermodynamical stable region obtained for this perovskite indicate its dynamical and thermodynamical stability. Using thermodynamic formalism of chemical potentials, $V_{\text{Cl}}$ ($V_{\text{Tl}}$) is identified as the most stable neutral point defect in Cl-poor (rich) environment. These findings reveal a significant excitonic effect in ${\mathrm{RbTlCl}}_3$ and provide valuable theoretical insights for discovering new potential photovoltaic materials within the inorganic perovskite family.

We formulate a weighted-Wasserstein framework for curvature statistics of cosmological large-scale structure. A coarse-grained density defines a weighted reference measure whose relative-entropy response separates into kinematic and density-induced Bakry-Émery contributions. On a Euclidean background, the latter is governed locally by $H_R=-{\nabla }^{2}ln{\rho }_R$; finite windows define density-weighted directional responses, while finite synthetic dimension subtracts a non-negative score-alignment deficit. The controlled local limit recovers the eigenvalue-threshold classification of the smoothed log-density Hessian, not a general equivalence with density-Hessian or gravitational-tidal classifiers. Independent smoothing and probe scales define a resolution flow. Controlled tests recover quadratic tensors to relative accuracy ${10}^{-9}$ or better and confirm $O\left(\varepsilon \right)$ and $O\left({\varepsilon }^2\right)$ convergence. In a periodic three-dimensional Zel’dovich mock, the specified six-direction transport tensor matches its direct finite-window reference with subpercent median error and directional correlation above 0.999 995. Rotated and enriched probe designs reveal appreciable finite-window eigenvalue and classification dependence, distinct from estimator error; a converged angular projection still has a nonquadratic directional residual. Under thinning to $f_{\mathrm{samp}}=1/16$, the six-direction internal error remains below $0.3\%$, while density reconstruction dominates the total error. At the fiducial radius, this finite-window observable has approximately $30\%$ lower normalized sampling error than the pointwise log-density Hessian, each relative to its own full-sampling reference. In the Gaussian-linear limit, curvature spectra are differential transforms of two-point statistics; finite-window and finite-dimensional observables retain additional profile and directional information beyond that limit.

Many interactions perturb (or shift) the hyperfine coupling in group-1 atoms between their nuclear spin and single valence electron. Previous work provided an approach to estimate this shift from electric-dipole interactions both during nonreactive collisions with other atoms or molecules at long range and with static electric fields. We extend this approach to estimate the shift due to a nearby conductive surface and improve all these estimates by numerically computing updated values for the characteristic energies they use. We investigate how to estimate these energies by scaling arguments and suggest how to adapt the approach to other applications. The results are relevant to pressure shifts in vapor cells, Stark shifts, and wall shifts in nanoscale devices.

The Alicki-Lindblad-Fannes (ALF) dynamical entropy measures the rate at which new information is gathered about a quantum system by inspecting its long-time evolution. After extending the ALF entropy to open quantum dynamics, we propose it as a measure of backflow of information from the environment. We show that the behavior of the open-system ALF entropy is a stronger witness than existing approaches based only on the open-system reduced dynamics. In the case of a qubit collisionally coupled to a classical spin chain, we obtain an exact expression for the open-system ALF entropy explicitly depending on the environment correlations. An extreme case shows how the information flow from environment to system corresponds to vanishing entropy production as for reversible finite quantum systems.

High-fidelity logical $T$-gate realization constitutes a core prerequisite for large-scale fault-tolerant quantum computing. However, conventional magic state distillation requires massive physical qubit overhead across successive distillation rounds, alongside sophisticated measurement and feedback control, thereby inducing considerable spatial and temporal resource consumption. Herein, we propose a controlled superconducting logical geometric $T$-gate scheme that achieves high-order suppression of universal errors simultaneously by integrating decoherence-free subspace encoding with multiloop optimized composite geometric pulse engineering. Guided by tailored trajectory design, we systematically establish unified gate construction frameworks for conventional geometric, composite geometric, and optimized composite geometric protocols. By flexibly controlling additional parametric degrees of freedom, the proposed scheme achieves substantially enhanced robustness against diverse noise sources. Numerical simulations reveal that, within tunable superconducting quantum circuits, our logical geometric $T$ gate outperforms both conventional logical composite geometric and logical dynamical $T$ gates in suppressing Rabi frequency, detuning, and residual interqubit crosstalk errors that can all be suppressed to the fourth order, while additionally providing inherent suppression of collective dephasing errors. The present strategy alleviates intrinsic limitations of mainstream approaches and opens a promising avenue toward robust high-fidelity logical $T$-gate construction.

The ${\mathrm{Sr}}_2{\mathrm{RuO}}_4\text{−}\mathrm{Ru}$ eutectic system, in which metallic Ru inclusions are embedded in an ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ matrix, exhibits an enhanced superconducting onset temperature of about 3 K, known as the 3-K phase. Here, we investigate the in-plane thermoelectric response of this eutectic system in the normal state and find a pronounced anisotropy in the thermopower for thermal gradients applied parallel and perpendicular to the Ru lamellae. To clarify its origin, we combine thermopower measurements with electronic-structure-based transport calculations and finite-element modeling of the local strain distribution generated by the thermal-expansion mismatch between ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ and Ru. The calculations show that uniaxial compression of ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ produces a sizable thermopower anisotropy through modification of the Fermi surfaces. When an idealized spatially inhomogeneous strain field around the Ru lamellae is included, the observed sign and qualitative magnitude of the anisotropy are reproduced more closely than in a simple unstrained two-component model. These results are consistent with a substantial contribution from strain-induced changes in the ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ electronic structure near the interfaces, although contributions from interfacial phase mixing and three-dimensional transport connectivity cannot be excluded.

Under atmospheric pressure, the ions that make up the plasma hardly obey electromagnetic pressure due to collisions with neutral particles, but electrons freeze in electromagnetic pressure, so the plasma flow is the propagation of electron. When plasma is irradiated onto a spherical or plate-shaped metal object, electrons become charged onto the object’s surface, and then the electrons are dispersed into the atmosphere due to repulsion. In a platelike structure, the charging of angular shapes concentrates the electric field, and electron emission occurs from these angular shapes depending on the intensity of the applied voltage used for plasma generation. A certain quantity of electromagnetic pressure is required for electrons to be released into the atmosphere from the angular section. Therefore, the quantity of electrons generated increases in proportion to the applied voltage, but when the applied voltage is low, electron emission due to the angular shape decreases, so the quantity of retentional electrons on the metal surface increases because the quantity of electrons generated far exceeds the quantity of electrons emitted. Consequently, when the applied voltage is lower, the quantity of electrons charged on the metal surface increases, so the applied voltage and the quantity of charged electrons are inversely proportional, and a negative permittivity is nominally occurred.