The time evolution of the entanglement entropy is a key concept to understand the structure of a nonequilibrium quantum state. In a large class of models, such evolution can be understood in terms of a semiclassical picture of moving quasiparticles spreading the entanglement throughout the system. However, it is not yet known how the entanglement splits between the sectors of an internal local symmetry of a quantum many-body system. Here, guided by the examples of conformal field theories and free-fermion chains, we show that the quasiparticle picture can be adapted to this goal, leading to a general conjecture for the charged entropies whose Fourier transform gives the desired symmetry-resolved entanglement $S_n\left(q\right)$. We point out two physically relevant effects that should be easily observed in atomic experiments: a delay time for the onset of $S_n\left(q\right)$ which grows linearly with $\left|\mathrm{\Delta }q\right|$ (the difference between the charge $q$ and its mean value) and an effective equipartition when $\left|\mathrm{\Delta }q\right|$ is much smaller than the subsystem size.

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• Entanglement entropy
• Quantum entanglement
• Quantum quench
• Conformal field theory