Conformality Lost

By D. Kaplan, Jong-Wan Lee, D. Son, M. Stephanov. 2009

335 citations recorded by the source corpus.

We consider zero-temperature transitions from conformal to non-conformal phases in quantum theories. We argue that there are three generic mechanisms for the loss of conformality in any number of dimensions: (i) fixed point goes to zero coupling, (ii) fixed point runs off to infinite coupling, or (iii) an IR fixed point annihilates with a UV fixed point and they both disappear into the complex plane. We give both relativistic and non-relativistic examples of the last case in various dimensions and show that the critical behavior of the mass gap behaves similarly to the correlation length in the finite temperature Berezinskii-Kosterlitz-Thouless (BKT) phase transition in two dimensions, xi ~ exp(c/|T-T_c|^{1/2}). We speculate that the chiral phase transition in QCD at large number of fermion flavors belongs to this universality class, and attempt to identify the UV fixed point that annihilates with the Banks-Zaks fixed point at the lower end of the conformal window.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/63936100c4ee045bc97f5fc01e25f3c0a91f9812

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In Nuclear and High Energy Physics

1. S. Sachdev
2. S. Hartnoll
3. Andrew Lucas
4. M. Mezei
5. Blaise Goutéraux
6. Hong Liu
7. T. Takayanagi
8. N. Iqbal

Citations in the corpus

• Holographic Quantum Matter (2016, methodology): “What happens if, by varying some auxiliary sources in the theory, we continuously push the effective IR mass squared of an operator through the instability bound (627)? It was explained in [433] that this should be understood as the annihilation of two RG flow fixed points.”
• Effective Theory for the Measurement-Induced Phase Transition of Dirac Fermions (2021, background): “This result may be rationalized by the fact that a gapless phase in (1 + 1) dimensions quite generically is left via the BKT mechanism by the generation of a mass [43].”
• Semi-local quantum liquids (2011, background): “Interestingly one finds that the analysis in AdS2 becomes almost identical [8, 51, 52] to that of the formation of three-body bound states in the Efimov effect [54].”
• Walking, weak first-order transitions, and complex CFTs (2018, background): “[5] in that they specialized early on to the large Nc limit, as well as used the holographic analogy.”
• Three loop analysis of the critical O (N) models in 6-ε dimensions (2014, background): “In [36] this was argued to happen at the lower (strongly coupled) edge of the conformal window for 4-dimensional SU(Nc) gauge theory with Nf flavors.”
• Holographic models for QCD in the Veneziano limit (2011, background): “The presence of several such solutions reflect the violation of the BF bound, and are reflecting the Efimov minima seen in other contexts (see [7, 10]).”