“{{w|Polyakov loop#Quark free energy|Quark liberation}} can be understood in a very simple way by means of the Peierls argument. Namely, while the energy of the string is proportional to its length, the entropy of it also grows linearly (since the number of random curves grows exponentially with their lengths). Thus at a certain temperature the entropy takes over and infinitely long strings begin to dominate. That means liberation.”