The Bethe Ansatz

This model is just like Lieb-Liniger, but for two colors of bosons: $$H={\int }_0^{L}dx\{\sum _{a=1,2}{\partial }_x{\mathrm{\Psi }}_a^{†}(x){\partial }_x{\mathrm{\Psi }}_a(x)+c\sum _{a,b}{\mathrm{\Psi }}_a^{†}(x){\mathrm{\Psi }}_b^{†}(x){\mathrm{\Psi }}_b(x){\mathrm{\Psi }}_a(x)\}$$