Quantum computing with collective ensembles of multi-level systems

TL;DR

This paper introduces a novel quantum computing approach using collective ensembles of multi-level systems, enabling scalable quantum registers through internal state manipulation and excitation blockade mechanisms.

Contribution

It presents a new physical scheme for quantum information encoding and processing in atomic ensembles leveraging collective internal states and excitation blockade.

Findings

Potential to build 10-20 qubit quantum computers in single atomic clouds

Linear scaling of register size with the number of internal atomic states

Feasibility of implementing one- and two-qubit gates via collective state transitions

Abstract

We propose a new physical approach for encoding and processing of quantum information in ensembles of multi-level quantum systems, where the different bits are not carried by individual particles but associated with the collective population of different internal levels. One- and two-bit gates are implemented by collective internal state transitions taking place in the presence of an excitation blockade mechanism which restricts the population of each internal state to the values zero and unity. 10-20 bit quantum computers can be built via this scheme in single trapped clouds of ground state atoms subject to the Rydberg excitation blockade mechanism, and the linear dependence between register size and the number of internal quantum states in atoms offers realistic means to reach larger registers.