Occupation number entanglement in mesoscopic conductors

Konrad Thomas, Christian Flindt

Guido Burkard

Peter Samuelsson, Μ. Büttiker

Vittorio Giovannetti, Diego Frustaglia, Fabio Taddei +1 more

We show that current correlations at the exit ports of a beam splitter can be used to detect electronic entanglement for a fairly general input state. This includes the situation where electron pairs can enter the beam splitter from the same port, or be separated due to backscattering. The proposed scheme allows us to discriminate between occupation-number and degree-of-freedom entanglement.

Elsa Prada, Fabio Taddei, Rosario Fazio

We analyze the effect of decoherence on the violation of the Clauser-Horne (CH) inequality for the full electron counting statistics in a mesoscopic multiterminal conductor. Our setup consists of an entangler that emits a flux of entangled electrons into two conductors characterized by a scattering matrix and subject to decoherence. Loss of phase memory is modeled phenomenologically by introducing fictitious extra leads. The outgoing electrons are detected using spin-sensitive electron counters. Given a certain average number of incoming entangled electrons, the CH inequality is evaluated as a function of the numbers of detected particles and on the various quantities characterizing the scattering matrix. When decoherence is turned on, we show that the amount of violation of the CH inequality is effectively reduced. Interestingly we find that, by adjusting the parameters of the system, there exists a protected region of $Q$ values for which violation holds for arbitrary strong decoherence.

Fabio Taddei, Vittorio Giovannetti, Diego Frustaglia +3 more

We show that current correlations at the exit ports of a beam splitter can be used to detect electronic entanglement for a fairly general input state. First, we demonstrate that multi‐mode entanglement of electrons in a mesoscopic conductor can be detected by a measurement of the zero‐frequency current correlations in an electronic Hong‐Ou‐Mandel interferometer. By this means, one can further establish a lower bound to the entanglement of formation of two‐electron input states. Second, we include the situation where electron pairs can enter the beam splitter from the same port or be separated due to backscattering. The proposed scheme allows to discriminate between particle‐number and mode entanglement.