Devil's crevasse and macroscopic entanglement in two-component Bose-Einstein condensates

TL;DR

This paper investigates the generation and properties of macroscopic entanglement in two-component Bose-Einstein condensates, revealing fractal structures and dependence on gate timing, with implications for quantum information processing.

Contribution

It provides a detailed analysis of entanglement dynamics in two spin-1/2 BECs, highlighting fractal structures and the impact of gate timing on entanglement robustness.

Findings

Entanglement exhibits fractal characteristics in two-component BECs.

Large particle number entanglement depends on rational or irrational gate times.

Macroscopic entanglement remains observable under certain decoherence conditions.

Abstract

Spin coherent states are the matter equivalent of optical coherent states, where a large number of two component particles form a macroscopic state displaying quantum coherence. Here we give a detailed study of entanglement generated between two spin-1/2 BECs due to an Sz1 Sz2 interaction. The states that are generated show a remarkably rich structure showing fractal characteristics. In the limit of large particle number N, the entanglement shows a strong dependence upon whether the entangling gate times are a rational or irrational multiple of pi/4. We discuss the robustness of various states under decoherence and show that despite the large number of particles in a typical BEC, entanglement on a macroscopic scale should be observable as long as the gate times are less than hbar/J sqrt[N], where J is the effective BEC-BEC coupling energy. Such states are anticipated to be useful for various quantum information applications such as quantum teleportation and quantum algorithms.