The suppression of quarkonium production in nucleus-nucleus collisions was originally proposed as a signal of colour deconfinement. Strong “anomalous” J/ψ suppression in Pb-Pb collisions has been reported at this Conference by the NA50 Collaboration. Is this suppression really anomalous? Can we conclude that the quark-gluon plasma is already discovered? What has to be done next? I address these...

The depletion of gluons as the parton flux traverses a nucleus in a heavy-ion collision can influence the production rate of heavy-quark states. Thus the suppression of J/ψ can be due to gluon depletion in the initial state in addition to nuclear and hadronic absorption in the final state. A formalism is developed to describe the depletion effect. It is shown that, without constraints from othe...

We analyse the mechanism in which zero modes lead to an elimination of fermionic color non–singlet states in 1+1 dimensions. Using a hamiltonian lattice formulation we clarify the physical meaning of the zero modes but we do not find support for speculations on the crucial importance of lower dimensional fields (zero modes in 1+1 dimension) for the infrared behavior of QCD in 2+1 or higher dime...

let $r$ be a commutative ring with identity. an ideal $i$ of a ring $r$is called an annihilating ideal if there exists $rin rsetminus {0}$ such that $ir=(0)$ and an ideal $i$ of$r$ is called an essential ideal if $i$ has non-zero intersectionwith every other non-zero ideal of $r$. thesum-annihilating essential ideal graph of $r$, denoted by $mathcal{ae}_r$, isa graph whose vertex set is the set...

Numerical simulations of numerous quantum systems suffer from the notorious sign problem. Important examples include QCD and other field theories at non-zero chemical potential, at non-zero vacuum angle, or with an odd number of flavors, as well as the Hubbard model for high-temperature superconductivity and quantum antiferromagnets in an external magnetic field. In all these cases standard sim...

In this paper, a new adaptive critic design is proposed to approximate the online Nash equilibrium solution for robust trajectory tracking control of non-zero-sum (NZS) games continuous-time uncertain nonlinear systems. First, augmented system was constructed by combining error and reference trajectory. By modifying cost function, problem transformed into an optimal problem. Based on dynamic pr...