Genuine multipartite correlations in systems invariant by particle permutations

Antonio Lourenco, PhD; University of Iowa

Systems invariant by particle permutations are present in many physical models, such as Lipkin-Meshkov-Glick (LMG) model, Dicke model, and boundary time crystal (BTC), among others. These systems possess critical phenomena where the knowledge of the correlations plays a key role, mainly describing quantum phase transition (QPT). Generally, the correlations, such as entanglement entropy and quantum discord, are studied between bipartitions or among all the subsystems for pure states. The question if k-particles are genuinely correlated is less restricted and more informative, it had been addressed very recently in the literature. In this seminar, I will present the study of the genuine multipartite correlations (GMC) in three systems invariant by particle permutations, Dicke superradiance, the LMG model, and in the BTC. Also, to complement the investigation of the GMC, we tried to witness genuine k-partite entanglement in the BTC model through the calculus of the quantum Fisher information, once that entanglement is a useful resource in many quantum tasks. The results show that GMC capture the QPTs and describes well the systems studied. However, the GMC encompass both classical and quantum correlations in the measure. So, it is necessary to apply other tools to differentiate the nature of the correlations.