Catálogo de publicaciones - revistas

<jats:p> <jats:italic>We study the properties of breather interactions in nonlinear Kerr media with self-steepening and spacetime correction and with either self-focusing or self-defocusing nonlinearity, and present a new family of exact breather solutions via the Darboux transformation with a special-designed quadratic spectral parameter. In contrast to the previous results of the nonlinear Schrödinger equation (NLSE) hierarchy, we show that the relative phase of colliding breathers has a significant effect on the collision manifestation. In particular, only the out-of-phase interactions can generate small amplitude waves at the collision center, which are analogous to the NLSE super-regular breathers. Our results will deepen our understanding of the properties of breather interactions and they will offer the possibility of experimental observations of super-regular breather dynamics in systems with self-steepening and spacetime correction.</jats:italic> </jats:p>

<jats:p> <jats:italic>A quantum system in complex potentials obeying parity-time (</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>) symmetry could exhibit all real spectra, starting out in non-Hermitian quantum mechanics. The key physics behind a</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>-symmetric system consists of the balanced gain and loss of the complex potential. We plan to include the nonequilibrium nature (i.e., the intrinsic kinds of gain and loss of a system) to a</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>-symmetric many-body quantum system, with an emphasis on the combined effects of non-Hermitian due to nonequilibrium nature and</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>symmetry in determining the properties of a system. To this end, we investigate the static and dynamical properties of a dark soliton of a polariton Bose–Einstein condensate under the</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>-symmetric non-resonant pumping by solving the driven-dissipative Gross–Pitaevskii equation both analytically and numerically. We derive the equation of motion for the center of mass of the dark soliton’s center analytically with the help of the Hamiltonian approach. The resulting equation captures how the combination of the open-dissipative character and</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal P }{ \mathcal T }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_040502_ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>-symmetry affects the properties of the dark soliton; i.e., the soliton relaxes by blending with the background at a finite time. Further numerical solutions are in excellent agreement with the analytical results.</jats:italic> </jats:p>

<jats:p> <jats:italic>Recent discoveries of dynamic ice VII and superionic ice highlight the importance of ionic diffusions in discriminating high-pressure (P) water phases. The rare event nature and the chemical bond breaking associated with these diffusions, however, make extensive simulations of these processes unpractical to ab initio and inappropriate for force field based methods. Using a first-principles neural network potential, we performed a theoretical study of water at 5–70 GPa and 300–3000 K. Long-time dynamics of protons and oxygens were found indispensable in discriminating several subtle states of water, characterized by proton’s and oxygen ion’s diffusion coefficients and the distribution of proton’s displacements. Within dynamic ice VII, two types of proton transfer mechanisms, i.e., translational and rotational transfers, were identified to discriminate this region further into dynamic ice VII T and dynamic ice VII R. The triple point between ice VII, superionic ice (SI), and liquid exists because the loosening of the bcc oxygen skeleton is prevented by the decrease of interatomic distances at high P’s. The melting of ice VII above ∼40 GPa can be understood as a process of two individual steps: the melting of protons and the retarded melting of oxygens, responsible for the forming of SI. The boundary of the dynamic ice VII and SI lies on the continuation line ice VII’s melting curve at low P’s. Based on these, a detailed phase diagram is given, which may shed light on studies of water under P’s in a wide range of interdisciplinary sciences.</jats:italic> </jats:p>

<jats:p> <jats:italic>The problem of how long it takes for an electron to tunnel from one side of a barrier to the other has been debated for decades and the attoclock is a promising experimental procedure to address this problem. In the attoclock experiment, many physical effects will contribute to the experimental results and it is difficult to extract the tunneling time accurately. We numerically investigate a method of measuring the residual equivalent temporal offset (RETO) induced by the physical effects except for tunneling delay. The Coulomb potential effect, the nonadiabatic effect, the multielectron effect, and the Stark effect are considered in the theoretical model. It is shown that the ratio of the RETO of the target atoms to that of H is insensitive to the wavelength and is linearly proportional to</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${(2{I}_{p})}^{-3/2}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mo stretchy="true">(</mml:mo> <mml:mn>2</mml:mn> <mml:msub> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="true">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_043201_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. <jats:italic>This work can help to improve the accuracy of the attoclock technique.</jats:italic> </jats:p>

<jats:p> <jats:italic>Angular distributions of fragment ions from ionization of several tri-atomic molecules (CO</jats:italic> <jats:sub>2</jats:sub>, <jats:italic>OCS, N</jats:italic> <jats:sub>2</jats:sub> <jats:italic>O and NO</jats:italic> <jats:sub>2</jats:sub> <jats:italic>) by strong 800-nm laser fields are investigated via a time-of-flight mass spectrometer. Anisotropic angular distributions of fragment ions, especially those of atomic ions, are observed for all of the molecules studied. These anisotropic angular distributions are mainly due to the geometric alignment of molecules in the strong field ionization. Distinct different patterns in ionic angular distributions for different molecules are observed. It is indicated that both molecular geometric structure and ionization channels have effects on the angular distributions of strong field ionization/fragmentation.</jats:italic> </jats:p>

<jats:p> <jats:italic>We perform a precision atom interferometry experiment to test the universality of free fall. Our experiment employs the Bragg atom interferometer with <jats:sup>87</jats:sup>Rb atoms either in hyperfine state</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA $\left|F=1,{m}_{F}=0\right.\rangle $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close="〉" open="|"> <mml:mrow> <mml:mi>F</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1</mml:mn> <mml:mo>,</mml:mo> <mml:msub> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>F</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_043701_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>or</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA $\left|F=2,{m}_{F}=0\right.\rangle $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close="〉" open="|"> <mml:mrow> <mml:mi>F</mml:mi> <mml:mo>=</mml:mo> <mml:mn>2</mml:mn> <mml:mo>,</mml:mo> <mml:msub> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>F</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_043701_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:italic>and the wave packets in these two states are diffracted by one pair of Bragg beams alternatively, which is helpful for suppressing common-mode systematic errors. We obtain an Eötvös ratio</jats:italic> <jats:inline-formula> <jats:tex-math> <?CDATA ${\eta }_{1-2}=\left(0.9\pm 2.7\right)\times {10}^{-10}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>η</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mn>0.9</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2.7</mml:mn> </mml:mrow> </mml:mfenced> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>10</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_4_043701_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:italic>and set a new record on the precision with improvement of nearly 5 times. This measurement also provides constraint on the difference of the diagonal terms of the mass-energy operator.</jats:italic> </jats:p>

<jats:p> <jats:italic>We propose a new algorithm for the error correction of scanning positions in ptychographic microscopy. Since the scanning positions are varied mechanically by moving the illuminating probes laterally, the scanning errors will accumulate at multiple positions, greatly reducing the reconstruction quality of a sample. To correct the scanning errors, we use the correlation analysis for the diffractive data combining with the additional constraint of dual wavelengths. This significantly improves the quality of ptychographic microscopy. Optical experiments verify the proposed algorithm for two samples including a resolution target and a fibroblast.</jats:italic> </jats:p>

<jats:p> <jats:italic>The multiwavelength characteristics of stimulated Raman scattering (SRS) in YVO</jats:italic> <jats:sub>4</jats:sub> <jats:italic>crystal excited by a picosecond laser at 1064nm are investigated theoretically and experimentally. Laser output with seven wavelengths is achieved coaxially and synchronously at 894, 972, 1175, 1312, 1486, 1713 and 2022nm in a YVO</jats:italic> <jats:sub>4</jats:sub> <jats:italic>crystal. The maximum total Raman output energy is as high as 2.77 mJ under the pump energy of 7.75 mJ. A maximum total Raman conversion efficiency of 47.8% is obtained when the pump energy is 6.54 mJ. This is the highest order of Stokes components and the highest output energy generated by YVO</jats:italic> <jats:sub>4</jats:sub> <jats:italic>reported up to date. This work expands the Raman spectrum of YVO</jats:italic> <jats:sub>4</jats:sub> <jats:italic>crystal to the near-IR regime, with seven wavelengths covered at the same time, paving the way for new wavelength generation in the near-IR regime and its multiwavelength application.</jats:italic> </jats:p>

<jats:p> <jats:italic>We demonstrate that the transport of hot carriers may result in the phenomenon where an oscillated output current appears at the waveforms in a high-power photoconductive semiconductor switch (PCSS) working at long pulse width when the laser disappears or the electric field changes. The variational laser and electric field will affect the scattering rates of hot carriers and crystal lattice in high-power PCSS, and the drift velocity of hot carriers and also the on-state resistance will be changed. The present result is important for reducing the on-state resistance and improving the output characteristics of high-power Si/GaAs PCSS.</jats:italic> </jats:p>

<jats:p> <jats:italic>We investigate the pressure spectral characteristics and the effective tuning of defect emissions in hexagonal boron nitride (hBN) at low temperatures using a diamond anvil cell (DAC). It is found that the redshift rate of emission energy is up to 10 meV/GPa, demonstrating a controllable tuning of single photon emitters through pressure. Based on the distribution character of pressure coefficients as a function of wavelength, different kinds of atomic defect states should be responsible for the observed defect emissions.</jats:italic> </jats:p>