QTRAJ 1.0: A Lindblad equation solver for heavy-quarkonium dynamics

We introduce an open-source package called QTraj that solves the Lindblad equation for heavy-quarkonium dynamics using the quantum trajectories algorithm. The package allows users to simulate the suppression of heavy-quarkonium states using externally-supplied input from 3+1D hydrodynamics simulations. The code uses a split-step pseudo-spectral method for updating the wave-function between jumps, which is implemented using the open-source multi-threaded FFTW3 package. This allows one to have manifestly unitary evolution when using real-valued potentials. In this paper, we provide detailed documentation of QTraj 1.0, installation instructions, and present various tests and benchmarks of the code.

本研究介绍一款名为QTraj的开源软件包，该工具借助量子轨迹（quantum trajectories）算法求解重夸克偶素（heavy-quarkonium）动力学的林德布拉德（Lindblad）方程。该软件包支持用户利用来自三维加一维（3+1D）流体动力学模拟的外部输入数据，模拟重夸克偶素态的淬灭过程。该代码采用分步伪谱法（split-step pseudo-spectral method）更新跳变之间的波函数，其实现依赖于开源多线程FFTW3软件包。这使得在使用实值势场时，演化过程可直观地保持幺正性。本文中，我们提供了QTraj 1.0的详细文档、安装指南，并展示了该代码的各类测试与基准测试结果。