[Physics] Lattice QCD and string theory

gauge-theorylattice-modelquantum-chromodynamicsstring-theory

I've heard the claim that some aspects of string theory are used to improve Monte-Carlo simulations of lattice QCD, for example by people working at the LHC.
I know a bit about Monte-Carlo methods in lattice QCD, but have no idea of how string theory ideas are applied to QCD at all, so I'd like to ask for

  • a short explanation of how and why string theory ideas are applied to QCD in general and

  • how they can be used in Monte-Carlo simulations of lattice QCD in particular.

References are welcome, too, of course. Maybe I should have looked for them myself, but I'm sure I'll get some useful recommendations much faster this way 🙂

Edit: Let's narrow the question down to: How can ideas in string theory be used to improve Monte-Carlo simulations of lattice QCD? (Lattice QCD is to be understood in the sense of strict SM without any ideas beyond the SM like supersymmetry, Ads/Cft etc.)

Best Answer

I don't know that much about lattice QCD, but I do know a few things about string theory and the gauge/string duality approach to QCD. I'm pretty sure the answer to your question is that ideas in string theory have not been used to improve Monte-Carlo simulations of QCD. Unified versions of string theory can't since they involve physics much above the QCD scale. Gauge/string duality models are still too crude, typically giving answers that are sometimes accurate to 15% but not in a well controlled approximation. The only way that I can see there being a smidgen of truth to the claim about using string ideas to improve lattice QCD is through the renormalization group improvement of lattice actions for QCD, an idea which I believe goes back to Symanzik. If you google "lattice QCD renormalization group improvement" you will find a number of reviews. Some ideas from string theory have improved our ability to do perturbative QCD calculations, and the RG improvement techniques are based on perturbative calculations, so it is just possible that this is the link that was mentioned to you. However I am not aware of this actually being the case, that is of a calculation of an RG improved lattice action that required new techniques from string theory in order to do the perturbative QCD calculations.

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