Coherent Tunneling Adiabatic Passage with the Alternating Coupling Scheme

TL;DR

This paper explores a new geometry for Coherent Tunneling Adiabatic Passage (CTAP) with alternating couplings, demonstrating its potential for long-range quantum transport in silicon-based systems.

Contribution

It introduces a novel alternating coupling scheme for CTAP, along with simplified protocols and realistic gate designs for long-range quantum particle transport.

Findings

Estimated adiabatic operation time of ~70ns for a 5-donor chain.

Proposed scheme is compatible with measured electron spin and charge relaxation times.

Provides a new approach for long-range quantum transport in silicon-based quantum devices.

Abstract

The use of adiabatic passage techniques to mediate particle transport through real space, rather than phase space is becoming an interesting possibility. We have investigated the properties of Coherent Tunneling Adiabatic Passage (CTAP) with alternating tunneling matrix elements. This geometry, not previously considered in the donor in silicon paradigm, provides an interesting route to long-range quantum transport. We introduce simplified coupling protocols, and transient eigenspectra as well as a realistic gate design for this transport protocol. Using a pairwise treatment of the tunnel couplings for a 5 donor device with 30nm donor spacings, 120nm total chain length, we estimate the time scale required for adiabatic operation to be ~70ns, a time well within measured electron spin and estimated charge relaxation and times for phosphorus donors in silicon.