Double quantum dot turnstile as an electron spin entangler

TL;DR

This paper analyzes how a double quantum dot system can reliably generate and detect entangled electron spins, emphasizing the importance of tunneling, bias, and wavepacket effects for quantum information applications.

Contribution

It demonstrates that a double quantum dot turnstile can serve as an efficient spin entangler and filter under specific experimental conditions, considering wavepacket dynamics.

Findings

Double quantum dots can act as efficient spin entanglers.

Wavepacket effects influence entanglement detection.

Tunable barriers are crucial for optimal performance.

Abstract

We study the conditions for a double quantum dot system to work as a reliable electron spin entangler, and the efficiency of a beam splitter as a detector for the resulting entangled electron pairs. In particular, we focus on the relative strengths of the tunneling matrix elements, the applied bias and gate voltage, the necessity of time-dependent input/output barriers, and the consequence of considering wavepacket states for the electrons as they leave the double dot to enter the beam splitter. We show that a double quantum dot turnstile is, in principle, an efficient electron spin entangler or entanglement filter because of the exchange coupling between the dots and the tunable input/output potential barriers, provided certain conditions are satisfied in the experimental set-up.