Some thoughts on critical and tricritical points and deconfinement

Abstract

We start with a discussion of a phase diagram and three special collision energies: (i) the first touching of the mixed phase; (ii) the softest point; (iii) the critical point. We then proceed to more details about the role a massless critical mode should play in the particle interaction and the elliptic flow. We then enter a discussion of whether high density QGP is or is not strongly coupled, and if so what one can say about color superconductivity domain using universality and data on trapped ultracold fermionic atoms. At the end, we briefly discuss deconfinement, or more specifically on whether there are precursors of the QCD strings at $T>T_c$, as well as possible role of magnetically charged excitations (monopoles and dyons).