In this article, we review on narrowband photon pairs produced in nonlinear crystals, and especially in atomic ensembles. In atomic ensembles, “write–read” process in pulse mode and spontaneous four-wave mixing process (SFWM) in continuous mode are two popular photon pair generation schemes. We specifically discuss the experimental works with continuous SFWM scheme in cold atomic ensembles. Photon pairs produced in these systems are characteristic of controllable long coherence time, and therefore are accessible with direct temporal modulation. We elaborate on the recent techniques on modulation and waveform reshaping of narrow-band paired photons.

So far no mechanism is known, which could connect the two measurements in an Aspect-type experiment. Here, we suggest such a mechanism, based on the phase of a photon’s field during propagation. We show that two polarization measurements are correlated, even if no signal passes from one point of measurement to the other. The non-local connection of a photon pair is the result of its origin at a common source, where the two fields acquire a well defined phase difference. Therefore, it is not actually a non-local effect in any conventional sense. We expect that the model and the detailed analysis it allows will have a major impact on quantum cryptography and quantum computation.

Based on the quantization scheme of the radiation fields in the dispersive and absorptive magnetic media, the normally ordered correlation functions of the outgoing field through a metamaterial plate are obtained. Then the relative photon-number densities of the transmitted field, the reflected field and the absorbed field are gotten through the correlation functions. Furthermore, the contributions of the relative permittivity and permeability of the metamaterials to the transmission are analyzed. Our results show that the permittivity and permeability reinforce the transmission for frequencies that are big compared with the magnetic resonance frequency.

Within Lie algebraic model, the vibrational chaotic dynamics in triatomic molecules are studied. The molecules of {\mathrm{H}}_2\mathrm{S}, {\mathrm{NO}}_2, and {\mathrm{O}}_3 are sampled to explore the dynamical differences between the local and normal mode molecules. The comprehensive effects of the local and normal mode vibrations, resonances and chaos on the dynamical entanglement are studied. The results demonstrate that the resonances as well as chaos can promote the evolution of dynamical entanglement.

We report a facile method of preparing novel branched silver nanowire structures such as Y-shaped, K-shaped and other multi-branched nanowires. These branched nanostructures are synthesized by reducing silver nitrate (AgNO₃) in polyethylene glycol (PEG) with polyvinglpyrrolidone (PVP) as capping agent. Statistical data indicate that for the “y” typed branched nanowire, the branches grow out from the side of the trunk nanowire in a preferential orientation with an angle of 55° between the branch and the trunk. Transmission electron microscopy (TEM) studies indicate that the defects on silver nanowires could support the growth of branched nanowires. Conditions such as the molar ratio of PVP/AgNO₃, the reaction temperature, and the degree of polymerization of reducing agent and PVP play important roles in determining the yield of the silver branches. Due to the rough surface, these branched nanostructures can be used as efficient substrates for surface-enhanced Raman scattering applications.

In this work, we present a schematic configuration and device model for a graphene-nanoribbon (GNR)-array-based nanolaser, which consists of a three-variable rate equations that takes into account carrier capture and Pauli blocking in semiconductor GNR-array lasers to analyze the steady-state properties and dynamics in terms of the role of the capture rate and the gain coefficient in GNR array nanolasers. Furthermore, our GNR-array nanolaser device model can be determined as two distinct two-variable reductions of the rate equations in the limit of large capture rates, depending on their relative values. The first case leads to the rate equations for quantum well lasers, exhibiting relaxation oscillations dynamics. The second case corresponds to GNRs nearly saturated by the carriers and is characterized by the absence of relaxation oscillations. Our results here demonstrated that GNR-array as gain material embedded into a high finesse microcavity can serve as an ultralow lasing threshold nanolaser with promising applications ranging widely from optical fiber communication with increasing data processing speed to digital optical recording and biology spectroscopy.

This article provides an introduction to on-shell recursion relations for calculations of tree-level amplitudes. Starting with the basics, such as spinor notations and color decompositions, we expose analytic properties of gauge-boson amplitudes, BCFW-deformations, the large z-behavior of amplitudes, and on-shell recursion relations of gluons. We discuss further developments of on-shell recursion relations, including generalization to other quantum field theories, supersymmetric theories in particular, recursion relations for off-shell currents, recursion relation with nonzero boundary contributions, bonus relations, relations for rational parts of one-loop amplitudes, recursion relations in 3D and a proof of CSW rules. Finally, we present samples of applications, including solutions of split helicity amplitudes and of \mathcal{N}=4 SYM theories, consequences of consistent conditions under recursion relation, Kleiss–Kuijf (KK) and Bern–Carrasco–Johansson (BCJ) relations for color-ordered gluon tree amplitudes, Kawai–Lewellen–Tye (KLT) relations.

Processes for decoding the genetic information in cells, including transcription, replication, recombination and repair, involve the deformation of DNA from its equilibrium structures such as bending, stretching, twisting, and unzipping of the double helix. Single-molecule manipulation techniques have made it possible to control DNA conformation and simultaneously detect the induced changes, revealing a rich variety of mechanically-induced conformational changes and thermodynamic states. These single-molecule techniques helped us to reveal the physics of DNA and the processes involved in the passing on of the genetic code.

In this mini-review we summarize the progress of Lattice Boltzmann (LB) modeling and simulating compressible flows in our group in recent years. Main contents include (i) Single-Relaxation-Time (SRT) LB model supplemented by additional viscosity, (ii) Multiple-Relaxation-Time (MRT) LB model, and (iii) LB study on hydrodynamic instabilities. The former two belong to improvements of physical modeling and the third belongs to simulation or application. The SRT-LB model supplemented by additional viscosity keeps the original framework of Lattice Bhatnagar–Gross–Krook (LBGK). So, it is easier and more convenient for previous SRT-LB users. The MRT-LB is a completely new framework for physical modeling. It significantly extends the range of LB applications. The cost is longer computational time. The developed SRT-LB and MRT-LB are complementary from the sides of convenience and applicability.