Single spin universal Boolean logic

TL;DR

This paper demonstrates that a linear array of three quantum dots with single electron spins can function as a universal NAND gate, achieving extremely low energy dissipation close to fundamental limits, advancing quantum-dot-based classical logic.

Contribution

It introduces a quantum-dot-based NAND gate architecture using spin states, showing it can operate with minimal energy dissipation near the Landauer limit.

Findings

The quantum dot array acts as a universal NAND gate.

Energy dissipation during switching approaches the Landauer-Shannon limit.

The proposed gate dissipates about 21 kT, much less than traditional transistors.

Abstract

Recent advances in manipulating single electron spins in quantum dots have brought us close to the realization of classical logic gates based on representing binary bits in spin polarizations of single electrons. Here, we show that a linear array of three quantum dots, each containing a single spin polarized electron, and with nearest neighbor exchange coupling, acts as the universal NAND gate. The energy dissipated during switching this gate is the Landauer-Shannon limit of kTln(1/p) [T = ambient temperature and p = intrinsic gate error probability]. With present day technology, p = 1E-9 is achievable above 1 K temperature. Even with this small intrinsic error probability, the energy dissipated during switching the NAND gate is only ~ 21 kT, while today's nanoscale transistors dissipate about 40,000 - 50,000 kT when they switch.