Cohernece in permutation-invariant state enhances permutation-asymmetry

A Dicke state and its decohered state are invariant for permutation. However, when another qubits state to each of them is attached, the whole state is not invariant for permutation, and has a certain asymmetry for permutation. The amount of asymmetry can be measured by the number of distinguishable states under the group action or the mutual information. This paper investigates how the coherence of a Dicke state affects the amount of asymmetry. To address this problem asymptotically, we introduce a new type of central limit theorem by using several formulas on hypergeometric functions. We reveal that the amount of the asymmetry in the case with a Dicke state has a strictly larger order than that with the decohered state in a specific type of the limit.