2005/10/31 by C. Papageorgakis, Constantinos Papageorgakis, Sanjaye Ramgoolam +3
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Bound state #Cosmology and Gravitation Theories #Fuzzy sphere #Gauge theory #Geometry #Mathematical physics #Mathematics #Noncommutative and Quantum Gravity Theories #Noncommutative geometry #Physics #Quantum mechanics #String (physics) #hep-th
paper · pdf · doi:10.1088/1126-6708/2006/01/030
published as JHEP0601:030,2006 · 34 pages, Latex; v2: Minor correction in conformal transformation of couplings, references added
arxiv created 2005/11/01 · openalex publication_date 2006/01/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study fluctuations of time-dependent fuzzy two-sphere solutions of the non-abelian DBI action of D0-branes, describing a bound state of a spherical D2-brane with N D0-branes. The quadratic action for small fluctuations is shown to be identical to that obtained from the dual abelian D2-brane DBI action, using the non-commutative geometry of the fuzzy two-sphere. For some of the fields, the linearized equations take the form of solvable Lamé equations. We define a large-N DBI-scaling limit, with vanishing string coupling and string length, and where the gauge theory coupling remains finite. In this limit, the non-linearities of the DBI action survive in both the classical and the quantum context, while massive open string modes and closed strings decouple. We describe a critical radius where strong gauge coupling effects become important. The size of the bound quantum ground state of multiple D0-branes makes an intriguing appearance as the radius of the fuzzy sphere, where the maximal angular momentum quanta become strongly coupled.