M.N.Chernodub (ITEP, Moscow)
Embedded quark-gluon monopoles in QCD
We propose a new class of gauge-invariant defects in QCD The defects are closely resemble the embedded Nambu monopoles in the Standard Electroweak model. We argue that the ``embedded QCD monopoles'' are proliferating in the quark gluon plasma phase while in the low-temperature hadronic phase the spatial proliferation of these objects is suppressed. At realistic quark masses and zero chemical potential the hadronic and quark-gluon phases are generally believed to be connected by a smooth crossover across which all thermodynamic quantities are non-singular. We argue that these QCD phases are separated by a well-defined boundary -- known as the Kertesz line in condensed matter systems -- associated with the onset of the proliferation of the embedded QCD monopoles in the quark gluon plasma phase. Our results are supported by numerical simulations in lattice SU(2) Yang- Mills theory.