Over the past decade, the ongoing quest to realize coherent excitonic states in semiconductors has led to tremendous progress, and has provided us with a glimpse of the rich physics of spontaneous coherence in double quantum well systems. These systems provide a unique laboratory, in which effects of single-particle band structure and density and interparticle interactions on the properties of excitonic coherent states can be systematically explored.

The dual focus of the special issue will be on the experimental evidence of theoretical proposals for novel coherent states in double quantum well systems. With recent progress on bilayer quantum Hall systems in mind, this issue will become an international forum for researchers to present original research and to provide their perspective on the rapid developments and groundbreaking ideas in this broad field. The topics to be covered include, but are not limited to:

• Excitonic condensation in bilayer quantum Hall systems
• Coherent states and phase transitions in bilayer quantum Hall systems
• Excitonic condensation in electron-hole double quantum well systems
• Coherent states in electron-electron or hole-hole double quantum well systems
• Transport and photoluminescence signatures of coherent states
• BEC-BCS transition in coherent states in double quantum well systems

Before submission, authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/acmp/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/, according to the following timetable: