In this paper we study the solitonic string solutions of magnon and single spike type in the beta-deformed AdS_4 x CP3 background. We find the dispersion relations which are supposed to give the anomalous dimension of the gauge theory operators.
We study solutions for the rotating strings on the sphere with a background NS-NS field and on the Anti-de-Sitter spacetime. We show the existence of magnon and single spike solutions on R$times$S$^2$ in the presence of constant magnetic field as two
limiting cases. We also study the solution for strings on AdS$_3times$ S$^3$ with Melvin deformation. The dispersion relations among various conserved charges are shown to receive finite corrections due to the deformation parameter. We further study the rotating string on AdS$_3 times$ S$^3$ geometry with two conserved angular momenta on S$^3$ and one spin along the AdS$_3$. We show that there exists two kinds of solutions: a circular string solution and a helical string. We find out the dispersion relation among various charges and give physical interpretation of these solutions.
The non-linear nature of string theory on non-trivial backgrounds related to the AdS/CFT correspondence suggests to look for simplifications. Two such simplifications proved to be useful in studying string theory. These are the pp-wave limit which de
scribes point-like strings and the so called near flat space limit which connects two different sectors of string theory -- pp-waves and giant magnons. Recently another example of AdS/CFT duality emerged - $AdS_4/CFT_3$, which suggests duality between $mathcal N=6$ CS theory and superstring theory on $AdS_4times cp$. In this paper we study the near flat space limit of strings on the $AdS_4times cp$ background and discuss possible applications of the reduced theory.
We study the solutions for fundamental string rotating in a background generated by a 1+1 dimensional intersection of two orthogonal stacks of fivebranes in type IIB string theory. We show the existence of magnon like solutions for the string moving
simultaneously in the two spheres in this background and find the relevant dispersion relation among the various conserved charges.
It is proved that when 8 fermions associated with the supersymmetries broken by the AdS_4 x CP^3 superbackground are gauged away by using the kappa-symmetry corresponding equations obtained by variation of the AdS_4 x CP^3 superstring action are cont
ained in the set of fermionic equations of the OSp(4|6)/(SO(1,3) x U(3)) sigma-model.
We generalize the one magnon solution in R X S^2 to unbounded M magnon and find the corresponding solitonic string configuration in the string sigma model. This configuration gives rise to the expected dispersion relation obtained from the spin chain
model in the large t Hooft coupling limit. After considering (M,M) multi-magnon or spike on R X S^2 X S^2 as a subspace of AdS(5)XS^5 or AdS(4)XCP^3, we investigate the dispersion relation and the finite size effect for (M,M) multi-magnon or spike.