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<jats:p>A higher-twist modified parton evolution equation is used to evolve the initial valence quark distributions in pions, which are derived based on light-front quantization via BLFQ collaboration. The results are consistent with the valence quark distributions of the E615 experiment, and the pion structure function of the H1 experiment. The structure function data highlight the necessity for a higher-twist modification in the small <jats:italic>x</jats:italic> region. Comparisons with some other models are also given.</jats:p>

<jats:p>We carry out a detailed study of the low-lying states of AlH and AlH<jats:sup>+</jats:sup>, using a multireference configuration interaction method. Based on the computed potential energy curves, the spectroscopic constants of bound <jats:italic>Λ</jats:italic>–<jats:italic>S</jats:italic> states are fitted; these agree with the results for the measurements. The values of the permanent dipole moment of the <jats:italic>Λ</jats:italic>–<jats:italic>S</jats:italic> states are calculated, and the charge transfer mechanism is discussed. Based on the calculated transition dipole moments and vibrational levels, the radiative lifetimes of bound states are determined. Finally, tunneling lifetimes, and <jats:italic>ν</jats:italic>′ = 0–2 vibrational levels of 4<jats:sup>2</jats:sup> <jats:italic>Σ</jats:italic> <jats:sup>+</jats:sup> and 3<jats:sup>2</jats:sup> <jats:italic>Π</jats:italic> states with a potential barrier are investigated.</jats:p>

<jats:p>We investigate <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> air lasing at 391 nm, induced by strong laser fields in a nitrogen glow discharge plasma. We generate forward <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> air lasing on the <jats:inline-formula> <jats:tex-math><?CDATA ${B}^{2}{\Sigma }_{{\rm{u}}}^{+}({v}^{\prime}=0)$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>B</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">u</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>v</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn5.gif" xlink:type="simple" /> </jats:inline-formula>–<jats:inline-formula> <jats:tex-math><?CDATA ${X}^{2}{\Sigma }_{{\rm{g}}}^{+}({v}^{^{\prime\prime} }=0)$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>X</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">g</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>v</mml:mi> <mml:mo>″</mml:mo> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> transition at 391 nm by irradiating an intense 35-fs, 800-nm laser in a pure nitrogen gas, finding that the 391-nm lasing quenches when the nitrogen gas is electrically discharged. In contrast, the 391-nm fluorescence measured from the side of the laser beam is strongly enhanced, demonstrating that this discharge promotes the population in the <jats:inline-formula> <jats:tex-math><?CDATA ${B}^{2}{\Sigma }_{{\rm{u}}}^{+}({v}^{\prime}=0)$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>B</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">u</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>v</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn7.gif" xlink:type="simple" /> </jats:inline-formula> state. By comparing the lasing and fluorescence spectra of the nitrogen gas obtained in the discharged and laser-induced plasma, we show that the quenching of <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn8.gif" xlink:type="simple" /> </jats:inline-formula> lasing is caused by the efficient suppression of population inversion between the <jats:inline-formula> <jats:tex-math><?CDATA ${B}^{2}{\Sigma }_{{\rm{u}}}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>B</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">u</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn9.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA ${X}^{2}{\Sigma }_{{\rm{g}}}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>X</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">g</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn10.gif" xlink:type="simple" /> </jats:inline-formula> states of <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn11.gif" xlink:type="simple" /> </jats:inline-formula>, in which a much higher population occurs in the <jats:inline-formula> <jats:tex-math><?CDATA ${X}^{2}{\Sigma }_{{\rm{g}}}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>X</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">g</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn12.gif" xlink:type="simple" /> </jats:inline-formula> state in the discharge plasma. Our results clarify the important role of population inversion in generating <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn13.gif" xlink:type="simple" /> </jats:inline-formula> air lasing, and also indicate the potential for the enhancement of <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{N}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn14.gif" xlink:type="simple" /> </jats:inline-formula> lasing via further manipulation of the population in the <jats:inline-formula> <jats:tex-math><?CDATA ${X}^{2}{\Sigma }_{{\rm{g}}}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>X</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:msubsup> <mml:mi>Σ</mml:mi> <mml:mi mathvariant="normal">g</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_38_4_043301_ieqn15.gif" xlink:type="simple" /> </jats:inline-formula> state in the discharged medium.</jats:p>

<jats:p>Multi-mode quantum memory is a basic element required for long-distance quantum communication, as well as scalable quantum computation. For on-demand readout and long storage times, control pulses are crucial in order to transfer atomic excitations back and forth into spin excitations. Here, we introduce noise-robust composite pulse sequences for high-fidelity excitation transfer in multi-mode quantum memory. These pulses are robust to the deviations in amplitude and the detuning parameters of realistic conditions. We show the efficiency of these composite pulses with a typical rare-earth ion-doped system. This approach could be applied to a variety of quantum memory schemes.</jats:p>

<jats:p>Based on the self-consistent phonon theory, the spectral energy density is calculated by the canonical transformation and the Fourier transformation. Through fitting the spectral energy density by the Lorentzian profile, the phonon frequency as well as the phonon relaxation time is obtained in one-dimensional nonlinear lattices, which is validated in the Fermi–Pasta–Ulam-<jats:italic>β</jats:italic> (FPU-<jats:italic>β</jats:italic>) and <jats:italic>ϕ</jats:italic> <jats:sup>4</jats:sup> lattices at different temperatures. The phonon mean free path is then evaluated in terms of the phonon relaxation time and phonon group velocity. The results show that, in the FPU-<jats:italic>β</jats:italic> lattice, the phonon mean free path as well as the phonon relaxation time displays divergent power-law behavior. The divergent exponent coincides well with that derived from the Peierls–Boltzmann theory at weak anharmonic nonlinearity. The value of the divergent exponent expects a power-law divergent heat conductivity with system size, which violates Fourier’s law. For the <jats:italic>ϕ</jats:italic> <jats:sup>4</jats:sup> lattice, both the phonon relaxation time and mean free path are finite, which ensures normal heat conduction.</jats:p>

<jats:p>Using the particle-in-cell simulations, we report an efficient scheme to generate a slow wave structure in the electron density of a plasma waveguide, based on the array laser–plasma interaction. The spatial distribution of the electron density of the plasma waveguide is modulated via effective control of the super-Gaussian index and array pattern code of the lasers. A complete overview of the holding time, and the bearable laser’s intensity of the electron density structure of the plasma waveguide, is obtained. In addition, the holding time of the slow wave structure of the plasma waveguide is also controlled by adjusting the frequency of the array laser beam. Finally, effects due to ion motion are discussed in detail.</jats:p>

<jats:p>We reproduce nonlinear behaviors, including frequency chirping and mode splitting, referred to as bump-on-tail instabilities. As has been reported in previous works, the generation and motion of phase-space hole-clump pairs in a kinetically driven, dissipative system can result in frequency chirping. We provide examples of frequency chirping, both with and without pure diffusion, in order to illustrate the role of the diffusion effect, which can suppress holes and clumps; Asymmetric frequency chirpings are produced with drag effect, which is essential to enhance holes, and suppress clumps. Although both diffusion and drag effect suppress the clumps, downward sweepings are observed, caused by a complicated interaction of diffusion and drag. In addition, we examine the discrepancies in frequency chirping between marginally unstable, and far from marginally unstable cases, which we elucidate by means of a dissipative system. In addition, mode splitting is also produced via BOT code for a marginal case with large diffusion.</jats:p>

<jats:p>The critical gradient mode (CGM) is employed to predict the energetic particle (EP) transport induced by the Alfvén eigenmode (AE). To improve the model, the normalized critical density gradient is set as an inverse proportional function of energetic particle density; consequently, the threshold evolves during EP transport. Moreover, in order to consider the EP orbit loss mechanism in CGM, ORBIT code is employed to calculate the EP loss cone in phase space. With these improvements, the AE enhances EPs radial transport, pushing the particles into the loss cone. The combination of the two mechanisms raises the lost fraction to 6.6%, which is higher than the linear superposition of the two mechanisms. However, the loss is still far lower than that observed in current experiments. Avoiding significant overlap between the AE unstable region and the loss cone is a key factor in minimizing EP loss.</jats:p>

<jats:p>We numerically investigate the Coriolis force effect on the suppression of an explosive burst, triggered by the neo-classical tearing mode, in reversed magnetic shear configuration tokamak plasmas, using a reduced magnetohydrodynamic model, including bootstrap current. Previous works have shown that applying differential poloidal rotation, with rotation shear located near the outer rational surface, is an effective way to suppress an explosive burst. In comparison with cases where there is no Coriolis force, the amplitude of differential poloidal rotation required to effectively suppress the explosive burst is clearly reduced once the effect of Coriolis force is taken into consideration. Moreover, the effective radial region of the rotation shear location is broadened in cases where the Coriolis force effect is present. Applying rotation with shear located between the radial positions of <jats:italic>q</jats:italic> <jats:sub>min</jats:sub> and the outer rational surface always serves to effectively suppress explosive bursts, which we anticipate will reduce operational difficulties in controlling explosive bursts, and will consequently prevent plasma disruption in tokamak experiments.</jats:p>

<jats:p>Gallium arsenide (GaAs), a typical covalent semiconductor, is widely used in the electronic industry, owing to its superior electron transport properties. However, its brittle nature is a drawback that has so far significantly limited its application. An exploration of the structural deformation modes of GaAs under large strain at the atomic level, and the formulation of strategies to enhance its mechanical properties is highly desirable. The stress-strain relations and deformation modes of single-crystal and nanotwinned GaAs under various loading conditions are systematically investigated, using first-principles calculations. Our results show that the ideal strengths of nanotwinned GaAs are 14% and 15% higher than that of single-crystal GaAs under pure and indentation shear strains, respectively, without producing a significantly negative effect in terms of its electronic performance. The enhancement in strength stems from the rearrangement of directional covalent bonds at the twin boundary. Our results offer a fundamental understanding of the mechanical properties of single crystal GaAs, and provide insights into the strengthening mechanism of nanotwinned GaAs, which could prove highly beneficial in terms of developing reliable electronic devices.</jats:p>