Catálogo de publicaciones - revistas

<jats:p>The effect of final-state dynamic correlation is investigated for ionization of atomic hydrogen by 75-keV proton impact by analyzing double differential cross sections. The final state is represented by a continuum correlated wave (CCW-PT) function which accounts for the interaction between the projectile and the target nucleus (PT interaction). The correlated final state is nonseparable solutions of the wave equation combining the dynamics of the electron motion relative to the target and projectile, satisfying the Redmond’s asymptotic conditions corresponding to long range interactions. The transition matrix is evaluated using the CCW-PT function and the undistorted initial state. Both the correlation effects and the PT interaction are analyzed by the present calculations. The convergence of the continuous correlated final state is examined carefully. Our results are compared with the absolute experimental data measured by Laforge <jats:italic>et al.</jats:italic> [<jats:italic>Phys. Rev. Lett.</jats:italic> <jats:bold>103</jats:bold>, 053201 (2009)] and Schulz <jats:italic>et al.</jats:italic> [<jats:italic>Phys. Rev. A</jats:italic> <jats:bold>81</jats:bold>, 052705 (2010)], as well as other theoretical models (especially the results of the latest non perturbation theory). We have shown that the dynamic correlation plays an important role in the ionization of atomic hydrogen by proton impact. While overall agreement between theory and the experimental data is encouraging, detailed agreement is still lacking. However, such an analysis is meaningful because it provides valuable information about the dynamical correlation and PT interaction in the CCW-PT theoretical model.</jats:p>

<jats:p>We investigate both the quantum and classical dynamics of a non-Hermitian system via a kicked rotor model with <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_29_12_120302_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> symmetry. For the quantum dynamics, both the mean momentum and mean square of momentum exhibit the staircase growth with time when the system parameter is in the neighborhood of the <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_29_12_120302_ieqn1a.gif" xlink:type="simple" /> </jats:inline-formula> symmetry breaking point. If the system parameter is much larger than the <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_29_12_120302_ieqn1b.gif" xlink:type="simple" /> </jats:inline-formula> symmetry breaking point, the accelerator mode results in the directed spreading of the wavepackets as well as the ballistic diffusion in momentum space. For the classical dynamics, the non-Hermitian kicking potential leads to the exponentially-fast increase of classical complex trajectories. As a consequence, the imaginary part of the trajectories exponentially diffuses with time, while the real part exhibits the normal diffusion. Our analytical prediction of the exponential diffusion of imaginary momentum and its breakdown time is in good agreement with numerical results. The quantum signature of the chaotic diffusion of the complex trajectories is reflected by the dynamics of the out-of-time-order correlators (OTOC). In the semiclassical regime, the rate of the exponential increase of the OTOC is equal to that of the exponential diffusion of the complex trajectories.</jats:p>

<jats:p>In quantum information technologies, quantum weak measurement is beneficial for protecting coherence of systems. In order to further improve the protection effect of quantum weak measurement on coherence, we propose an optimization scheme of quantum Fisher information (QFI) protection in an open quantum system by combing no-knowledge quantum feedback control with quantum weak measurement. On the basis of solving the dynamic equations of a stochastic two-level quantum system under feedback control, we compare the effects of different feedback Hamiltonians on QFI and find that via no-knowledge quantum feedback, the observation operator <jats:italic>σ<jats:sub>x</jats:sub> </jats:italic> (or <jats:italic>σ<jats:sub>x</jats:sub> </jats:italic> and <jats:italic>σ<jats:sub>z</jats:sub> </jats:italic>) can protect QFI for a long time. Namely, no-knowledge quantum feedback can improve the estimation precision of feedback coefficient as well as that of detection coefficient.</jats:p>

<jats:p>The unconventional photon blockade (UPB) for low-frequency mode is investigated in a three-mode system with double second-order nonlinearity. By analyzing the Hamiltonian of the system, the optimal analytic condition of UPB in low-frequency mode is obtained. The numerical results are calculated by solving the master equation in a truncated Fock space, which agrees well with the analytic conditions. Through the numerical analysis of the system, it is found that the weak driving strength is favorable for the system to realize the UPB effect, and the system is insensitive to the changes of attenuation rate and environmental temperature. The comparison with the two-mode system and another similar three-mode system shows that, under similar system parameters, the UPB effect of this double two-order nonlinear system is more obvious.</jats:p>

<jats:p>We propose a square optical lattice in which some of neighbor hoppings have a Peierls phase. The Peierls phase makes the lattice have a special band structure and induces the existence of Dirac points in the Brillouin zone, which means that topological semimetals exist in the system. The Dirac points move with the change of the Peierls phase and the Dirac cones are anisotropic for some vales of the Peierls phase. The lattice has a novel hidden symmetry, which is a composite antiunitary symmetry composed of a translation operation, a sublattice exchange, a complex conjugation, and a local <jats:italic>U</jats:italic>(1) gauge transformation. We prove that the Dirac points are protected by the hidden symmetry and perfectly explain the moving of Dirac points with the change of the Peierls phase based on the hidden symmetry protection.</jats:p>

<jats:p>Within the framework of four-dimensional quadratic curvature gravities in the appearance of a negative cosmological constant, a definition for the gravitational energy of solutions with anti-de Sitter (AdS) asymptotics was put forward by Giribet <jats:italic>et al.</jats:italic> [<jats:italic>Phys. Rev. D</jats:italic> <jats:bold>98</jats:bold> 044046 (2018)]. This was achieved by adding proper topological invariant terms to the gravity action to render the variation problem well-posed. We prove that the definition via the procedure of topological regularization can be covered by our previous work [<jats:italic>Int. J. Mod. Phys. A</jats:italic> <jats:bold>35</jats:bold> 2050102 (2020)] in four dimensions. Motivated by this, we further generalize the results to generic diffeomorphism invariant theories of gravity in arbitrary even dimensions.</jats:p>

<jats:p>We focus on the localized characteristics of lump and interaction solutions to two extended Jimbo–Miwa equations. Based on the Hirota bilinear method and the test function method, we construct the exact solutions to the extended equations including lump solutions, lump–kink solutions, and two other types of interaction solutions, by solving the under-determined nonlinear system of algebraic equations for associated parameters. Finally, analysis and graphical simulation are presented to show the dynamical characteristics of our solutions and the interaction behaviors are revealed.</jats:p>

<jats:p>We address the issue of how disorder together with nonlinearity affect energy relaxation in the lattice <jats:italic>ϕ</jats:italic> <jats:sup>4</jats:sup> system. The absence of nonlinearity leads such a model to only supporting fully localized Anderson modes whose energies will not relax. However, through exploring the time decay behavior of each Anderson mode’s energy–energy correlation, we find that adding nonlinearity, three distinct relaxation details can occur. (i) A small amount of nonlinearity causes a rapid exponential decay of the correlation for all modes. (ii) In the intermediate value of nonlinearity, this exponential decay will turn to power-law with a large scaling exponent close to –1. (iii) Finally, all Anderson modes’ energies decay in a power-law manner but with a quite small exponent, indicating a slow long-time tail decay. Obviously, the last two relaxation details support a new localization mechanism. As an application, we show that these are relevant to the nonmonotonous nonlinearity dependence of thermal conductivity. Our results thus provide new information for understanding the combined effects of disorder and nonlinearity on energy relaxation.</jats:p>

<jats:p>Wu-Xing theory is an ancient philosophy that serves as a guiding principle in the traditional Chinese medicine (TCM). It has been used to explain the unbalance among the TCM organ systems in disease states and provide treatment philosophy qualitatively. Until now, it is still a challenge to explore the Wu-Xing theory beyond its philosophical nature. In this study, we established a quantitative framework using the landscape and flux theory to characterize the nature of the Wu-Xing theory from a perspective of a minimal network motif and leave certain specific functional aspects of Wu-Xing theory for future exploration. We uncovered the irregular ring shape of projection landscape for the Wu-Xing network with several local basins and barriers. We found that the dynamics of the self-organized Wu-Xing system was determined by the underlying negative landscape gradient force and the nonequilibrium rotational flux. While the shape of the Wu-Xing landscape determines the stabilities of the states, the rotational flux guarantees the persistent periodic oscillation and the stability of the flow. This provides a physical and quantitative basis for Yin–Yang duality of the driving forces for determining the dynamics and behaviors of the living systems. Applying landscape and flux analysis, we can identify the key parameter for the dynamics/function of Wu-Xing network. These findings allow us to have a deeper understanding of the scientific merits of the ancient Wu-Xing theory from the network motif perspective.</jats:p>