Table of contents

Quantum steering is the essential resource for quantum information processing. In this letter, a scheme is proposed to generate genuine quadripartite Einstein-Podolsky-Rosen (EPR) steering by an optical parametric oscillation cascaded with a sum-frequency process. Idler beam is generated by a difference frequency generation process between pump and injected signal in an optical superlattice. Then, a sum-frequency beam is produced by the cascaded sum-frequency process between pump and idler beams in the same optical superlattice by the quasi-phase-matching technique. The genuine quadripartite EPR steering among pump, signal, idler, and sum-frequency beams is confirmed in this scheme by applying a criteria for genuine multipartite EPR steering. The variation properties of the EPR steering with pump and nonlinear coupling coefficients are also discussed.

The postulate of universal local Weyl scaling (conformal) symmetry modifies both general relativity and the Higgs scalar field model. Conformal gravity (CG) has recently been fitted to rotation data for 138 galaxies. The conformal Higgs model (CHM) acquires a gravitational effect that fits observed Hubble expansion for redshifts $z\leq 1$ (7.33 Gyr) accurately with only one free constant parameter. Conformal theory explains dark energy and does not require dark matter, providing a viable alternative to the ΛCDM standard paradigm. Vanishing of centripetal acceleration outside a galactic halo boundary is a unique implication of the theory. The fit to observed astrophysical data by conformal models CG and CHM is shown here to account for both parameters w² and λ of postulated Higgs potential $V=-(w^2-\lambda\Phi^\dag\Phi)\Phi^\dag\Phi$, responsible for symmetry-breaking finite $\Phi^\dag\Phi$ in particle theory. Recent criticism of CG is resolved here by showing that CG and CHM are interdependent but compatible. Nonclassical CG radial acceleration parameter γ is determined by the CHM. A recently established empirical relationship between classical and nonclassical galactic radial acceleration requires parameter γ to be independent of galactic mass. Conformal theory is shown here to be consistent with this and with the v⁴ baryonic Tully-Fisher relation for galactic rotation velocities.

In this letter, the relativistic oscillators in $(3 + 1)$ dimensions in the context of the Magueijo-Smolin (MS) noncommutative model are considered. In order to appreciate the influence of this deformation, the energy eigenvalues and eigenfunctions are determined for both cases for the Klein-Gordon and the Dirac oscillators. Our calculations show however that the energies and wave functions of the relativistic oscillator are modified by the deformation parameter.

The scaling invariance for chaotic orbits near a transition from limited to unlimited diffusion in a dissipative standard mapping is explained via the analytical solution of the diffusion equation. It gives the probability of observing a particle with a specific action at a given time. We show the diffusion coefficient varies slowly with the time and is responsible for suppressing the unlimited diffusion. The momenta of the probability are determined and the behavior of the average squared action is obtained. The limits of small and large time recover the results known in the literature from the phenomenological approach and, as a bonus, a scaling for intermediate time is obtained as dependent on the initial action. The formalism presented is robust enough and can be applied in a variety of other systems including time-dependent billiards near a transition from limited to unlimited Fermi acceleration as we show at the end of the letter and in many other systems under the presence of dissipation as well as near a transition from integrability to non-integrability.

1$T'$-phase transition metal dichalcogenides possess lots of intriguing physical properties including superconductivity, large magnetoresistance and topological surface state. Here, we investigated the electrical transport properties of 2M WSe₂, which is constructed by $1T'$ WSe₂ layers. We found that the 2M WSe₂ has a high carrier mobility of $2.5 \times 10^{3}\ \text{cm}^{2}\text{V}^{-1}\text{S}^{-1}$ at 5 K. Moreover, large non-saturated magnetoresistance (MR) of 2M WSe₂ was observed to be up to 3500% at 2 K under a magnetic field of 9 T. The first-principle calculations show that 2M WSe₂ displays a typical-semimetal band structure with the coexistence of electron pockets and hole pockets.

A case of non-minimal couplings between gravity and electromagnetic fields is presented. The field equations are worked out in the language of exterior differential forms. A class of exact charge screening solutions is given with a specific discussion on the polarisation and magnetisation of space-time. The consequences of non-minimal couplings to gravity are examined.

We introduce a model of effective conformal quantum field theory in dimension $d=1+1$ coupled to stochastic noise, where Kardar-Parisi-Zhang (KPZ) class fluctuations can be observed. The analysis of the quantum dynamics of the scaling operators reduces to the study of random trajectories in a random environment, modeled by Brownian vector fields. We use recent results on random walks in random environments to calculate the time-dependent entanglement entropy of a subsystem interval, starting from a factorized state. We find that the fluctuations of the entropy in the large deviation regime are governed by the universal Tracy-Widom distribution. This enlarges the KPZ class, previously observed in random circuit models, to a family of interacting many-body quantum systems.

The transient fluctuation theorem is used to calibrate an atomic force microscope by measuring the fluctuations of the work performed by a time-dependent force applied between a colloidal probe and the surface. From this measure one can easily extract the value of the interaction force and the relevant parameters of the cantilever. The results of this analysis are compared with those obtained by standard calibration methods.

In this letter, we study the scattering of ${\text{spin-}}\frac{1}{2}$ particles from a spin-independent parity time $(\cal PT){\text{-symmetric}}$ complex potential, and for the first time, theoretically demonstrate the coexistence of $\cal PT{\text{-symmetric}}$ and $\cal PT$-broken phases for broadband energy spectra in this system. We also show the existence of anisotropic transmission resonances, accessible through the tuning of energy. Our results are promising for applications in spintronics, semiconductor-based devices, and a better understanding of the topological surface states.

We present a microwave photon detection scheme based on wavelength conversion in hybrid cavity system (electro-opto-mechanical converter). By converting microwave pulse into optical pulse efficiently, tough microwave photon detection can be switched to convenient optical photon detection. We demonstrate that a theoretical detection efficiency analogous to optical detection efficiency can be reached by selecting proper parameters. Pulse shapes of both wavelengths match well. Furthermore, we enhance the scheme by applying the Josephson parametric amplifier (JPA) and optical parametric amplifier (OPA) in the respective cavity, and we obtain a maximum detection efficiency enhancement of near 41% compared to the non-amplification case.

We theoretically analyze and numerically demonstrate that guided-mode resonance (GMR) effects can be achieved in acoustic systems. Similar to its optical counterpart, the acoustic GMR-like effects can support multiple narrow bandwidth transmission dips at a broad range of frequencies and give rise to strongly localized acoustic pressure fields in the acoustic waveguide layer. The discussed fundamental phenomena will allow a broad range of applications, including the design of filters, sensors, and other novel acoustic devices.

The efficiency of strain-mediated magnetoelectric composites is heavily reliant on the effectiveness of strain transfer between the different constituents. Many analytical and experimental studies have trialed various materials, geometries, and boundary conditions reporting the effect of these attributes on the magnetoelectric response. However, a more sophisticated, but not yet pursued, approach is to investigate the strain distribution in order to discern the factors that are most influential and to provide insight on how these factors should be manipulated to optimize the coupling efficacy. In this study, a mathematical model is developed to observe the radial and tangential strains in a concentric cylinder composite structure consisting of a piezoelectric outer layer bonded with a thin elastic layer to an inner piezomagnetic layer. Results from the study elucidate that the strain distribution behavior was dependent on the mechanical properties of the constituents as well as the bonding condition. Remarkably, analytical results showed that the direct magnetoelectric coefficient can be substantially enhanced, if probing takes place at strategic locations, i.e., leveraging strain localization, on the piezoelectric layer that maximize the difference between the radial displacements giving rise to higher magnetoelectric response.

Fake news causes an adverse effect on the regular public order and has become easier to propagate with the popularity of online social networks. The threat of fake news propagation makes it important to explore the vital nodes, which are defined as nodes with large branch sizes and hence generating a wider influence than others in this work. Previous studies about identifying vital nodes are mainly from single propagation of fake news networks, which do not consider that users may participate in different propagation networks. Here we identify vital nodes with the feature named the C_k-value that combines structural feature out-degree in a single network and multi-network user activeness. The C_k-value could reflect the branch size with a strong correlation, even at the early stage of propagation, and percolation based on C_k-value is more efficient than other indicators such as node activeness and out-degree. Thus, this research may provide a better understanding of vital nodes in the fake news propagation from topology properties, and further inspires innovative ways to identify vital nodes of fake news propagation.

Quantum transport through CNT-fluorographene-Ag junction is studied using density functional theory in combination with the Landauer-Büttiker formalism. Rectifying behavior is obtained for both single and bilayer fluorographene with rectification ratio exceeding 4. The asymmetric conductance originates from bias-dependent charge localization in the system as was revealed in transmission eigenstates analysis. These findings can be useful in developing metal-insulator-metal junctions for high-frequency applications.

Products of random matrix products of $\mathrm{SL}(2,\mathbb{R})$, corresponding to transfer matrices for the one-dimensional Schrödinger equation with a random potential V, are studied. I consider both the case where the potential has a finite second moment $\langle V^2\rangle<\infty$ and the case where its distribution presents a power law tail $p(V)\sim|V|^{-1-\alpha}$ for $0<\alpha<2$. I study the generalized Lyapunov exponent of the random matrix product (i.e., the cumulant generating function of the logarithm of the wave function). In the high-energy/weak-disorder limit, it is shown to be given by a universal formula controlled by a unique scale (single parameter scaling). For $\langle V^2\rangle<\infty$, one recovers Gaussian fluctuations with the variance equal to the mean value: $\gamma_2\simeq\gamma_1$. For $\langle V^2\rangle=\infty$, one finds $\gamma_2\simeq(2/\alpha) \gamma_1$ and non-Gaussian large deviations, related to the universal limiting behaviour of the conductance distribution $W(g)\sim g^{-1+\alpha/2}$ for $g\to0$.

The morphology of spherically confined flexoelectric fluid membrane vesicles in an external uniform electric field is studied numerically. Due to the deformations induced by the confinement, the membrane becomes polarized resulting in an interaction with the external field. The equilibrium shapes of the vesicle without electric field can be classified in a geometrical phase diagram as a function of scaled area and reduced volume (Kahraman O. et al., EPL, 97 (2012) 68008; Kahraman O. et al., New. J. Phys., 14 (2012) 095021). When the area of the membrane is only slightly larger than the area of the confining sphere, a single axisymmetric invagination appears. A non-vanishing electric field induces an additional elongation of the confined vesicle which is either perpendicular or parallel depending on the sign of the electric field parameter. Higher values of the surface area or the electric field parameter can reduce the symmetry of the system leading to more complex folding. We present the resulting shapes and show that transition lines are shifted in the presence of an electric field. The obtained folding patterns could be of interest for biophysical and technological applications alike.

Heterogeneity in dynamics in the form of non-Gaussian molecular displacement distributions appears ubiquitously in soft matter. We address the quantification of such heterogeneity using an information-theoretic measure of the distance between the actual displacement distribution and its nearest Gaussian estimation. We explore the usefulness of this measure in two generic scenarios of random walkers in heterogeneous media. We show that our proposed measure leads to a better quantification of non-Gaussianity than the conventional ones based on moment ratios.

Mutual extinction of light Active particle in a one-dimensional force field Simulating sleep apnea dynamics through random walk model Inconsistency of the conventional theory of superconductivity