Speaker: Zi-Long Li (Institute of Physics, Chinese Academy of Science)

Date & Time: 10am, Aug 28, 2023.

Room: Online (Zoom)

Title: Two-dimensional coherent spectroscopy and its applications in spin systems

Abstract: 

As a newly developed ultrafast optical spectroscopy, terahertz two-dimensional coherent spectroscopy(2DCS) has become a promising method to characterize the physical properties of optical excitations in various materials. It utilizes two or more THz pulses to detect the nonlinear response of materials, thereby incorporating multiple frequency variables.

In this talk, I will first provide a brief review of the basic knowledge of 2DCS. Next, I will demonstrate the application of 2DCS on the XXZ model in its gapless phase and explain the origin of the observed photon echo signal. Moreover, I will introduce a mechanism to acount for the decay of photon echo. Lastly, I will present the numerical results and extract the decay rate of photon echo, which aligns with the naive dimension counting.