IQIM Postdoctoral and Graduate Student Seminar

Friday February 26, 2016 4:00 PM

Casimir Effect, Theta Vacuum and Topological Order in QED

Speaker: Charles Cao, Physics, Caltech
Location: East Bridge 114

Abstract: We analyze the case where one imposes non-trivial spatal topology for a simple abelian gaug theory. As usual,the large gauge transformatons present in the system allow one to discuss theta vacuum and magneto-electric effect via the theta term. However, even for zero theta parameter, the tunneling transitions between different topologically inequivalent pre-vacua give rise to an additional contribution to vacuum energy that can be measured in the context of Casimir effect. Furthermore, photon production and non-trivial electric and magnetic responses can be induced by applying a global external field which behaves similar to an effective theta parameter. The theory in the far IR can be described by a TQFT and a phase transition occurs at effective theta = pi where the quantum vacuum has degeneracy two. Possible experimental implementations will also be discussed.


 

 

Series IQIM Postdoctoral and Graduate Student Seminar Series

Contact: Marcia Brown at 626-395-4013 marciab@caltech.edu