  We propose a versatile Loschmidt echo protocol to detect and quantify
multiparticle entanglement. It allows us to extract the quantum Fisher
information for arbitrary pure states, and finds direct application in quantum
metrology. In particular, the protocol applies to states that are generally
difficult to characterize, as non-Gaussian states, and states that are not
symmetric under particle exchange. We focus on atomic systems, including
trapped ions, polar molecules, and Rydberg atoms, where entanglement is
generated dynamically via long-range interaction, and show that the protocol is
stable against experimental detection errors.
