Macroscopic quantum information processing using spin coherent states

TL;DR

This paper elaborates on a quantum information processing scheme that employs spin coherent states of Bose-Einstein condensates, enabling qubit encoding and manipulation beyond the continuous variable regime, with potential for experimental realization.

Contribution

It provides a detailed framework for using spin coherent states in quantum algorithms, expanding on previous proposals and analyzing decoherence effects for practical implementation.

Findings

Framework for quantum algorithms with spin coherent states

Analysis of decoherence effects in proposed scheme

Discussion of experimental implementation possibilities

Abstract

Previously a new scheme of quantum information processing based on spin coherent states of two component Bose-Einstein condensates was proposed (Byrnes {\it et al.} Phys. Rev. A 85, 40306(R)). In this paper we give a more detailed exposition of the scheme, expanding on several aspects that were not discussed in full previously. The basic concept of the scheme is that spin coherent states are used instead of qubits to encode qubit information, and manipulated using collective spin operators. The scheme goes beyond the continuous variable regime such that the full space of the Bloch sphere is used. We construct a general framework for quantum algorithms to be executed using multiple spin coherent states, which are individually controlled. We illustrate the scheme by applications to quantum information protocols, and discuss possible experimental implementations. Decoherence effects are analyzed under both general conditions and for the experimental implementation proposed.