On the bound state in weakly coupled λ(ϕ6-ϕ4)2

We consider the λ(φ{symbol}⁶-φ{symbol}⁴) quantum field theory in two space-time dimensions. Using the Bethe-Salpeter equation, we show that there is a unique two particle bound state if the coupling constant λ>0 is sufficiently small. If m is the mass of single particles then the bound state mass is given by {Mathematical expression}