Feature Request: Lorentz Force Implementation in add_force for Magnetic Field Simulation

[Lenslike]

Dear Prof. Fan

Currently, GPUMD provides the add_force command, allowing users to apply external forces or approximate electric field effects on charged atoms. However, it appears that this command cannot be used to apply Lorentz forces to ions within a model, which is crucial for simulating the effects of magnetic fields as external stimuli.

I came across a related discussion here, which highlights the challenges of implementing Lorentz forces. Specifically, the issue is that "a magnetic field causes forces due to the velocity of charged atoms and not their position (like an electric field). That conflicts with the velocity-Verlet integration algorithm, which assumes that forces are dependent on position only."

I would like to know if GPUMD has any plans or capabilities to overcome this limitation and extend the add_force command to support Lorentz forces for ions? This feature would be highly beneficial for researchers simulating magnetic field effects.

Thanks!!!