Brillouin amplification is a new method to obtain high power hundred-picosecond laser pulses for shock ignition. The laser pulse＇s intensity can be amplified to 10 GW/cm^2 through this method. In order to determine t...Brillouin amplification is a new method to obtain high power hundred-picosecond laser pulses for shock ignition. The laser pulse＇s intensity can be amplified to 10 GW/cm^2 through this method. In order to determine the near-field quality, the relationship between the Brillouin amplification gain and the B integral in the stimulated Brillouin scattering（SBS） energy transfer process was studied, and numerical simulations and calculations were carried out to explain the process. For achieving an output intensity of 10 GW/cm^2 under the condition that the effect of small–scale self-focusing is insignificant in the Brillouin amplification, the influence of the configuration parameters on the Brillouin amplification and the B integral was investigated. The results showed that the 10 GW/cm^2 high power output can be obtained by optimizing the intensities of the pump and Stokes light and choosing an appropriate SBS medium.展开更多
The major difficulty for the Feynman Path Integral Monte Carlo (PIMC) simulations of the quantum systems of particles is the so called “sign problem”, arising due to the fast oscillations of the path integral integr...The major difficulty for the Feynman Path Integral Monte Carlo (PIMC) simulations of the quantum systems of particles is the so called “sign problem”, arising due to the fast oscillations of the path integral integrand depending on the complex-valued action. Our aim is to find universal techniques being able to solve this problem. The new method combines the basic ideas of the Metropolis and Hasting algorithms and is based on the Picard-Lefschetz theory and complex-valued version of Morse theory. The basic idea is to choose the Lefschetz thimbles as manifolds approaching the saddle point of the integrand. On this thimble the imaginary part of the complex-valued action remains constant. As a result the integrand on each thimble does not oscillate, so the “sign problem” disappears and the integral can be calculated much more effectively. The developed approach allows also finding saddle points in the complexified space of path integral integration. Some simple test calculations and comparisons with available analytical results have been carried out.展开更多
The topological magnon insulator on a honeycomb lattice with Dzyaloshinskii–Moriya interaction(DMI) is studied under the application of a circularly polarized light.At the high-frequency regime, the effective tight-b...The topological magnon insulator on a honeycomb lattice with Dzyaloshinskii–Moriya interaction(DMI) is studied under the application of a circularly polarized light.At the high-frequency regime, the effective tight-binding model is obtained based on Brillouin–Wigner theory.Then, we study the corresponding Berry curvature and Chern number.In the Dirac model, the interplay between a light-induced handedness-dependent effective DMI and intrinsic DMI is discussed.展开更多
We find a new complex integration-transform which can establish a new relationship between a two-mode operator's matrix element in the entangled state representation and its Wigner function. This integration keeps...We find a new complex integration-transform which can establish a new relationship between a two-mode operator's matrix element in the entangled state representation and its Wigner function. This integration keeps modulus invariant and therefore invertible. Based on this and the Weyl–Wigner correspondence theory, we find a two-mode operator which is responsible for complex fractional squeezing transformation. The entangled state representation and the Weyl ordering form of the two-mode Wigner operator are fully used in our derivation which brings convenience.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61378007 and 61138005)the Fundamental Research Funds for the Central Universities,China(Grant No.HIT.IBRSEM.A.201409)
文摘Brillouin amplification is a new method to obtain high power hundred-picosecond laser pulses for shock ignition. The laser pulse＇s intensity can be amplified to 10 GW/cm^2 through this method. In order to determine the near-field quality, the relationship between the Brillouin amplification gain and the B integral in the stimulated Brillouin scattering（SBS） energy transfer process was studied, and numerical simulations and calculations were carried out to explain the process. For achieving an output intensity of 10 GW/cm^2 under the condition that the effect of small–scale self-focusing is insignificant in the Brillouin amplification, the influence of the configuration parameters on the Brillouin amplification and the B integral was investigated. The results showed that the 10 GW/cm^2 high power output can be obtained by optimizing the intensities of the pump and Stokes light and choosing an appropriate SBS medium.
文摘The major difficulty for the Feynman Path Integral Monte Carlo (PIMC) simulations of the quantum systems of particles is the so called “sign problem”, arising due to the fast oscillations of the path integral integrand depending on the complex-valued action. Our aim is to find universal techniques being able to solve this problem. The new method combines the basic ideas of the Metropolis and Hasting algorithms and is based on the Picard-Lefschetz theory and complex-valued version of Morse theory. The basic idea is to choose the Lefschetz thimbles as manifolds approaching the saddle point of the integrand. On this thimble the imaginary part of the complex-valued action remains constant. As a result the integrand on each thimble does not oscillate, so the “sign problem” disappears and the integral can be calculated much more effectively. The developed approach allows also finding saddle points in the complexified space of path integral integration. Some simple test calculations and comparisons with available analytical results have been carried out.
基金Project supported by the National Natural Science Foundation of China(Grant No.61604106)Shandong Provincial Natural Science Foundation,China(Grant No.ZR2014FL025)
文摘The topological magnon insulator on a honeycomb lattice with Dzyaloshinskii–Moriya interaction(DMI) is studied under the application of a circularly polarized light.At the high-frequency regime, the effective tight-binding model is obtained based on Brillouin–Wigner theory.Then, we study the corresponding Berry curvature and Chern number.In the Dirac model, the interplay between a light-induced handedness-dependent effective DMI and intrinsic DMI is discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.11775208)Key Projects of Huainan Normal University,China(Grant No.2019XJZD04)。
文摘We find a new complex integration-transform which can establish a new relationship between a two-mode operator's matrix element in the entangled state representation and its Wigner function. This integration keeps modulus invariant and therefore invertible. Based on this and the Weyl–Wigner correspondence theory, we find a two-mode operator which is responsible for complex fractional squeezing transformation. The entangled state representation and the Weyl ordering form of the two-mode Wigner operator are fully used in our derivation which brings convenience.
