Strings and branes in anti-de Sitter spacetimes

This thesis investigates aspects of dynamics of strings and D-branes in Anti-De Sitter spacetimes. The examples considered include strings and D-branes in AdS₃ and strings in AdS ₅ × S5 which can be mapped to certain operators in the dual $N$ = 4 Super Yang Mills theory.; The AdS/CFT correspondence for string states in AdS ₅ × S₅ which flow into plane wave states in the Penrose limit is considered. The leading finite radius corrections to the string spectrum are compared with scaling dimensions of finite R-charge operators in the dual $N$ = 4 Super Yang Mills. It is shown that there is a precise agreement between string and gauge theory results.; The relation between the algebraic construction of boundary states in AdS₃ and the target space analysis of D-branes is investigated. The two descriptions are shown to be consistent. The overlap of a localized closed string state with boundary states is computed in the semiclassical regime. The boundary states are then identified with D-branes wrapping conjugacy classes in AdS₃. The string partition function on the disk is shown to reproduce the spacetime DBI action.