Bright standing soliton of the focusing nonlinear Schrodinger equation
= Bright standing soliton of the focusing nonlinear Schrodinger equation
{c}
For every $\kappa>0$ and $x_0\in\mathbb R$,
$$
\psi(x,t)=\kappa e^{i\kappa^2t}
\operatorname{sech}(\kappa(x-x_0))
$$
solves $i\psi_t+\psi_{xx}+2|\psi|^2\psi=0$ and decays rapidly as $|x|\to\infty$.