The Effective Theory of Long Strings

Understand

We present the low-energy effective theory on long strings in quantum field theory, including a streamlined review of previous literature on the subject.

• Such long strings can appear in the form of solitonic strings, as in the 4d Abelian Higgs model, or in the form of confining strings, as in Yang-Mills theories.
• The bottom line is that upon expanding in powers of 1/L the energy levels of long (closed) strings (where L is the length of the string), all the terms up to (and including) order 1/L^5 are universal.
• We argue that for excited strings in D>3 space-time dimensions there is a universal deviation at order 1/L^5 from the naive formula that is usually used to fit lattice results.