Natural Multiparticle Entanglement in a Fermi Gas

Author(s): C. Lunkes, Č. Brukner, V. Vedral

Journal: Physical Review Letters

Volume: 95

Page(s): 030503

Year: 2005

DOI Number: 10.1103/PhysRevLett.95.030503

Abstract:

We investigate multipartite entanglement in a noninteracting fermion gas, as a function of fermion separation, starting from the many particle fermion density matrix. We prove that all multiparticle entanglement can be built only out of two-fermion entanglement. Although from the Pauli exclusion principle we would always expect entanglement to decrease with fermion distance, we surprisingly find the opposite effect for certain fermion configurations. The von Neumann entropy is found to be proportional to the volume for a large number of particles even when they are arbitrarily close to each other. We will illustrate our results using different configurations of two, three, and four fermions at zero temperature although all our results can be applied to any temperature and any number of particles.

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