Quantum Fisher Information of Bipartitions of W States

Abstract

We study the quantum Fisher information (QFI) of W states and W -like states under decoherence. In particular, we nd that on the contrary to amplitude damping and depolarizing decoherence, a W -like state of 3 qubits obtained by discarding 1 qubit of a genuine W state of 4 qubits is more robust than a genuine W state of 3 qubits under amplitude amplifying and phase damping decoherence.