Entanglement of spins under a strong laser influence

TL;DR

This paper investigates how strong laser fields influence the entanglement dynamics of spins within a bound state, combining classical motion analysis with quantum spin evolution to understand entanglement behavior.

Contribution

It introduces a semiclassical approach that couples classical bound state motion with quantum spin dynamics under strong laser influence, including magnetic effects and beyond dipole approximation.

Findings

Entanglement dynamics depend on the classical trajectory of the bound state.

The approach models both maximally entangled and uncorrelated initial states.

Results show how laser parameters affect spin entanglement evolution.

Abstract

The fate of entanglement of spins for two heavy constituents of a bound state moving in a strong laser field is analyzed within the semiclassical approach. The bound state motion as a whole is considered classically beyond the dipole approximation and taking into account the magnetic field effect by using the exact solution to the Newton equation. At the same time the evolution of constituent spins under the laser influence is studied quantum mechanically. The spin density matrix is determined as solution to the von Neumann equation with the effective Hamiltonian, describing spin-laser interaction along the bound state classical trajectory. Based on the solution, the dynamics of concurrence of spins is calculated for the maximally entangled Werner states as well as for an initially uncorrelated state.