We make hamiltonian analyses of the new set of dual bosonic p-brane (in-cluding string) actions which contain high non-linearity. The di

The periodic bounce of Born-Infeld theory of D3-branes is derived, and the BPS limit of in nite period is discussed as an example of tachyon condensation. The explicit bounce solution to the Born-Infeld action is interpreted as an unstable fundamental string stretched between the brane and its antibrane.

The duality symmetries of various chiral boson actions are investigated using D=2 and D=6 space-time dimensions as examples. These actions involve the Siegel, Floreanini-Jackiw, Srivastava and Pasti-Sorokin-Tonin formulations. We discover that the Siegel, Floreanini-Jackiw and Pasti-Sorokin-Tonin actions have self-duality with respect to a common anti-dualization of chiral boson fields in D=2 and D56 dimensions, respectively, while the Srivastava action is self-dual with respect to a generalized dualization of chiral boson fields. Moreover, the action of the Floreanini-Jackiw chiral bosons interacting with gauge fields in D=2 dimensions also has self-duality but with respect to a generalized anti-dualization of chiral boson fields.

A Born-Infeld theory describing a D2-brane coupled to a 4-form RR field strength is considered, and the general solutions of the static and Euclidean time equations are derived and discussed. The period of the bounce solutions is shown to allow a consideration of tunneling and quantum-classical transitions in the sphaleron region. The order of such transitions, depending on the strength of the RR field strength, is determined. A criterion is then derived to confirm these findings.

Siegel's action is generalized to the D=2(p+1)-dimensional space-time (p even). The investigation of self-duality of chiral p-forms is extended to the momentum frame, using Siegel's action of chiral bosons in two space-time dimensions and its generalization in higher dimensions as examples. The whole procedure of the investigation is realized in the momentum space that relates to configuration space through the Fourier transformation of fields. These actions correspond to non-local Lagrangians in the momentum frame. Their selfduality with respect to dualization of chiral fields is uncovered. The relationship between two self-dual tensors in momentum space, whose form appears similar in configuration space, plays an important role in the calculation, that is, its application realizes the algebraic solution of an integral equation.