This is related to string theory
What do you know about it? What have you tried? Please show an attempt.
That's the equation that Michio Kaku uses to illustrate string field theory. On the right hand side, the first half is what we call a kinetic term (for motion of the string) and the second half is a potential term (for interactions of the string).
Thank you so much
Specifically, this is the Lagrangian for "cubic string field theory" of open strings. For pointers and references see nLab:string field theory. For a quick exposition see in the String theory FAQ the entry What are the equations of string theory?
And, most importantly: what's the question?
That's the question!
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