Instability of Solitons in Imaginary Coupling Affine toda Field Theory

This apparently tiny change /3-+ i/3 brings huge differences between the affine Toda field theory and its imaginary coupling counterpart. Among them the follow­ ing two aspects are most prominent: The first is the emergence of soliton solutions and other interesting exact solutions in the imaginary coupling theory, just as in the well-known sine~Gordon theory, which is the simplest example of the imaginary coupling affine Toda field theories. In contrast, the affine Toda field theory is known to have no solitons. The second is the lack of reality /hermiticity of the Lagrangian and action in all the imaginary coupling theories except for the sine-Gordon theory. Many interesting and beautiful results on solitons have been obtained by various authors. By applying Hirota's method, Hollowood 11 > obtained various simple soliton solutions in the an A complete set of soliton solutions was obtained by invoking