Existence and Limiting Profiles of Normalized Travelling Wave Solutions for the Pseudo-Relativistic Schrödinger Equation with Logarithmic Nonlinearity

We study the existence and asymptotic behaviour of normalized solutions to the following pseudo-relativistic Schrödinger equation with logarithmic nonlinearity $$(\sqrt{-\mathrm{\Delta }+m^2}-m)u+i(v\cdot \mathrm{\nabla })u+\lambda u=u\log \mathrm{\mid }u{\mathrm{\mid }}^2+\mathrm{\mid }u{\mathrm{\mid }}^{p-2}u,\text{in }{\mathbb{R}}^N,$$ under the mass constraint $$\mathrm{\parallel }u{\mathrm{\parallel }}_2^2=a,$$ where $m,a>0$, $2<p\le \frac{2N}{N-1}$ with $N\ge 2$, $v\in {\mathbb{R}}^N$ is the travelling velocity with $\mathrm{\mid }v\mathrm{\mid }<1$, and $\lambda \in \mathbb{R}$ appears as Lagrange multiplier, as minima of the corresponding energy on the constraint. By applying variational method, we first provide a complete classification of the existence and nonexistence of such minima. In particular, for the mass-critical case $p=2+\frac{2}{N}$, we show that there exists a constant $a_v^{\ast }$ which is a threshold for the existence. Based on this, we analyse the blow-up behaviour of such minimizers as $a$ approaches $a_v^{\ast }$ from below. Finally, we investigate the limiting profiles of minimizers to problem when $\underset{n\to \mathrm{\infty }}{\lim }{a}_n=a_0\in (0,+\mathrm{\infty })$ with $\{a_n\}\subset (0,+\mathrm{\infty })$ in the mass-subcritical case $2<p<2+\frac{2}{N}$ and $\underset{n\to \mathrm{\infty }}{\lim }{a}_n=a_0\in (0,a_v^{\ast })$ with $\{a_n\}\subset (0,a_v^{\ast })$ in the mass-critical case $p=2+\frac{2}{N}$, respectively.