Entanglement production in a chaotic quantum dot

TL;DR

This paper explores how chaotic scattering in a quantum dot can generate entangled electron pairs, providing a universal statistical framework and a practical method to measure entanglement via noise, independent of magnetic field conditions.

Contribution

It introduces a low-magnetic field setup for entanglement production in quantum dots using chaotic scattering, with a universal statistical description and a noise-based measurement approach.

Findings

Mean concurrence is nearly unaffected by time-reversal symmetry.

Entanglement can be measured through Bell inequality violations using noise.

Chaotic scattering provides a universal entanglement production mechanism.

Abstract

It has recently been shown theoretically that elastic scattering in the Fermi sea produces quantum mechanically entangled states. The mechanism is similar to entanglement by a beam splitter in optics, but a key distinction is that the electronic mechanism works even if the source is in local thermal equilibrium. An experimental realization was proposed using tunneling between two edge channels in a strong magnetic field. Here we investigate a low-magnetic field alternative, using multiple scattering in a quantum dot. Two pairs of single-channel point contacts define a pair of qubits. If the scattering is chaotic, a universal statistical description of the entanglement production (quantified by the concurrence) is possible. The mean concurrence turns out to be almost independent on whether time-reversal symmetry is broken or not. We show how the concurrence can be extracted from a Bell inequality using low-frequency noise measurements, without requiring the tunneling assumption of earlier work.