Coherence and Optical Emission from Bilayer Exciton Condensates

TL;DR

This paper reviews experiments on Bose-Einstein condensation of excitons in bilayer structures, focusing on coherence effects and testing methods to demonstrate macroscopic quantum phenomena in these systems.

Contribution

It provides a comprehensive review of experimental efforts and theoretical considerations for observing exciton condensation and coherence in bilayer quantum well structures.

Findings

Evidence of macroscopic coherence in excitonic systems

Discussion of proposed tests for off-diagonal long-range order

Analysis of past claims and experimental challenges

Abstract

Experiments aimed at demonstrating Bose-Einstein condensation of excitons in two types of experiments with bilayer structures (coupled quantum wells) are reviewed, with an emphasis on the basic effects. Bose-Einstein condensation implies the existence of a macroscopic coherence, also known as off-diagonal long-range order, and proposed tests and past claims for coherence in these excitonic systems are discussed.