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Quasiparticle entanglement: redefinition of the vacuum and reduced density matrix approach

P. Samuelsson·E. V. Sukhorukov·M. Buttiker
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Abstract

A scattering approach to entanglement in mesoscopic conductors with independent fermionic quasiparticles is discussed. We focus on conductors in the tunneling limit, where a redefinition of the quasiparticle vacuum transforms the wavefunction from a manybody product state of noninteracting particles to a state describing entangled two-particle excitations out of the new vacuum. The approach is illustrated with two examples (i) a normal-superconducting system, where the transformation is made between Bogoliubov-de Gennes quasiparticles and Cooper pairs, and (ii) a normal system, where the transformation is made between electron quasiparticles and electron-hole pairs. This is compared to a scheme where an effective two-particle state is derived from the manybody scattering state by a reduced density matrix approach.

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P. Samuelsson, E. V. Sukhorukov, M. Buttiker. 2005-03-01. Quasiparticle entanglement: redefinition of the vacuum and reduced density matrix approach. https://doi.org/10.1088/1367-2630%2F7%2F1%2F176

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