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<jats:p>We investigate entanglement of assistance without and with decoherence using a local non-Hermitian operation, i.e., parity–time (<jats:inline-formula> <jats:tex-math> <?CDATA ${\mathscr{P}}{\mathscr{T}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_12_120305_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>) symmetric operation. First we give the explicit expressions of entanglement of assistance for a general <jats:italic>W</jats:italic>-like state of a three-qubit system under a local parity–time symmetric operation. Then for a famous <jats:italic>W</jats:italic> state without decoherence, we find that entanglement of assistance shared by two parties can be obviously enhanced with the assistance of the third party by a local parity–time symmetric operation. For the decoherence case, we provide two schemes to show the effects of local parity–time symmetric operation on improvement of entanglement of assistance against amplitude damping noise. We find that for the larger amplitude damping case the scheme of <jats:inline-formula> <jats:tex-math> <?CDATA ${\mathscr{P}}{\mathscr{T}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_12_120305_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> symmetric operation performed on one of two parties with the influence of noise is superior to that of <jats:inline-formula> <jats:tex-math> <?CDATA ${\mathscr{P}}{\mathscr{T}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_12_120305_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> symmetric operation performed on the third party without the influence of noise in suppressing amplitude damping noise. However, for the smaller amplitude damping case the opposite result is given. The obtained results imply that the local <jats:inline-formula> <jats:tex-math> <?CDATA ${\mathscr{P}}{\mathscr{T}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_12_120305_ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> symmetric operation method may have potential applications in quantum decoherence control.</jats:p>

<jats:p>We propose a regular spherically symmetric spacetime solution with three parameters in Einstein gravity coupled to nonlinear electrodynamics (NED), which describes the NED black hole with electric charge. It is found that the system enclosed by the horizon of NED spacetime satisfies the first law of thermodynamics. In order to obtain the NED spacetime with only electric charge, the case of two parameters taking the same value is considered. In this case, we express the mass of the NED spacetime as a function of the entropy and electric charge of the NED black hole, give the Smarr-like formula and the approximate Smarr formula for the mass of NED spacetime.</jats:p>

<jats:p>According to the Herglotz variational principle and differential variational principle of Herglotz type, we study the adiabatic invariants for a non-conservative nonholonomic system. Firstly, the differential equations of motion of the non-conservative nonholonomic system based upon the generalized variational principle of Herglotz type are given, and the exact invariant for the non-conservative nonholonomic system is introduced. Secondly, a new type of adiabatic invariant for the system under the action of a small perturbation is obtained. Thirdly, the inverse theorem of the adiabatic invariant is given. Finally, an example is given.</jats:p>

<jats:p>A two-dimensional binary driven disk system embedded by impermeable tilted plates is investigated through nonequilibrium computer simulations. It is well known that a binary disk system in which two particle species are driven in opposite directions exhibits jammed, phase separated, disordered, and laning states. The presence of tilted plates can not only advance the formation of laning phase, but also effectively stabilize laning phase by suppressing massively drifting behavior perpendicular to the driving force. The lane width distribution can be controlled easily by the interplate distance. The collective behavior of driven particles in laning phase is guided by the funnel-shaped confinements constituted by the neighboring tilted plates. Our results provide the important clues for investigating the mechanism of laning formation in driven system.</jats:p>

<jats:p>The three-coupling modified nonlinear Schrödinger (MNLS) equation with variable-coefficients is used to describe the dynamics of soliton in alpha helical protein. This MNLS equation with variable-coefficients is firstly transformed to the MNLS equation with constant-coefficients by similarity transformation. And then the one-soliton and two-soliton solutions of the variable-coefficient-MNLS equation are obtained by solving the constant-coefficient-MNLS equation with Hirota method. The effects of different parameter conditions on the soliton solutions are discussed in detail. The interaction between two solitons is also discussed. Our results are helpful to understand the soliton dynamics in alpha helical protein.</jats:p>

<jats:p>Optical nanofiber (ONF) is a special tool for effectively controlling coupling of light and atoms. In this paper, we study the ladder-type electromagnetically induced transparent (EIT) under ultralow power level in a warm cesium vapor by observing the transmission of ONF that couples the 6S → 6P Cs atoms in the presence of a 6P → 8S control beam through the same fiber. The linewidth and transmission of the EIT signal are investigated at different intensities of the control laser. In addition, we theoretically study the nonlinear interaction at the ONF interface using the multi-level density matrix equations, and obtain good agreements between theory and experiments. The results may have great significance for further study of optical nonlinear effect at low power level.</jats:p>

<jats:p>A surface plasmon resonance (SPR) sensor with two orthogonal open loops based on microstructured optical fibers (MOFs) is introduced. The interaction between core mode and surface plasmon polariton (SPP) mode produced by two different metal films is studied. Full vector finite element method is used to analyze the coupling and sensing characteristics. The results show that there are three loss peaks near the Au/Ag film, and multi-peak calibration is achieved. Because of the positive and negative sensitivity of the amplitude, the sensor has strong anti-interference capability when the external environment changes. The sensor can detect the refractive index between 1.37 and 1.40, and the working wavelength is between 1600 nm and 2400 nm. Because the sensor has some excellent characteristics, it can be used in biochemical sensing, environmental detection, and other related fields.</jats:p>

<jats:p>A compact all-fiber polarization-maintaining Er:laser using a nonlinear amplifying loop mirror is reported. Fundamental single-pulse mode-locking operation can always self start, with a cavity round-trip decreased from ∼ 4.7 m to ∼ 1.7 m. When the pulse repetition rate is 121.0328 MHz, output pulse is measured to have a center wavelength/3-dB spectral bandwidth/radio frequency signal to noise ratio (SNR)/pulse width of 1571.65 nm/18.70 nm/80 dB/477 fs, respectively. Besides, three states including the exponential growth, damping state, and steady state are investigated through the build-up process both experimentally and numerically. Excellent stability of this compact Er:laser is further evaluated, demonstrating that it can be an easy-fabrication maintenance-free ultrafast candidate for the scientific area of this kind.</jats:p>

<jats:p>We describe the synthesis of three-dimensional (3D) multilayer ZnO@Ag/SiO<jats:sub>2</jats:sub>@Ag nanorod arrays by the physico–chemical method. The surface-enhanced Raman scattering (SERS) performance of the 3D multilayer ZnO@Ag/SiO<jats:sub>2</jats:sub>@Ag nanorod arrays is studied by varying the thickness of dielectric layer SiO<jats:sub>2</jats:sub> and outer-layer noble Ag. The 3D ZnO@Ag/SiO<jats:sub>2</jats:sub>@Ag nanorod arrays create a huge number of SERS “hot spots” that mainly contribute to the high SERS sensitivity. The great enhancement of SERS results from the electron transfer between ZnO and Ag and different electromagnetic enhancements of Ag nanoparticles (NPs) with different thicknesses. Through the finite-difference time-domain (FDTD) theoretical simulation, the enhancement of SERS signal can be ascribed to a strong electric field enhancement produced in the 3D framework. The simplicity and generality of our method offer great advantages for further understanding the SERS mechanism induced by the surface plasmon resonance (SPR) effect.</jats:p>

<jats:p>Optical features of a semiconductor–dielectric photonic crystal are studied theoretically. Alternating layers of micrometer sized SiO<jats:sub>2</jats:sub>/InSb slabs are considered as building blocks of the proposed ideal crystal. By inserting additional layers and disrupting the regularity, two more defective crystals are also proposed. Photonic band structure of the ideal crystal and its dependence on the structural parameters are explored at the first step. Transmittance of the defective crystals and its changes with the thicknesses of the layers are studied. After extracting the optimum values for the thicknesses of the unit cells of the crystals, the optical response of the proposed structures at different temperatures and incident angles are investigated. Changes of the defect layers’ induced mode(s) are discussed by taking into consideration of the temperature dependence of the InSb layer permittivity. The results clearly reflect the high potential of the proposed crystals to be used at high temperature terahertz technology as a promising alternative to their electronic counterparts.</jats:p>