On demand entanglement in double quantum dots via coherent carrier scattering

TL;DR

This paper demonstrates how controlled electron scattering can generate and recover entanglement between two quantum dots, with potential applications in quantum information processing.

Contribution

It introduces a method to control entanglement in double quantum dots via weak electron currents and analyzes the coherence recovery with multiple electrons.

Findings

Single electrons induce decoherence of the quantum dots.

Properly energized multiple electrons can restore quantum coherence.

Transmission spectra reveal entangled states through scattering signatures.

Abstract

We show how two qubits encoded in the orbital states of two quantum dots can be entangled or disentangled in a controlled way through their interaction with a weak electron current. The transmission/reflection spectrum of each scattered electron, acting as an entanglement mediator between the dots, shows a signature of the dot-dot entangled state. Strikingly, while few scattered carriers produce decoherence of the whole two-dots system, a larger number of electrons injected from one lead with proper energy is able to recover its quantum coherence. Our numerical simulations are based on a real-space solution of the three-particle Schroedinger equation with open boundaries. The computed transmission amplitudes are inserted in the analytical expression of the system density matrix in order to evaluate the entanglement.