On Charmonia Survival Above Deconfinement

We study charmonium correlators and spectral functions at zero and finite temperature using anisotropic lattices at several different lattice spacings. We find evidence for survival of 1S charmonia states at leas till $1.5T_c$ and dissolution of 1P states at $1.16T_c$.Comment: contribution to the 29th Johns Hopkins Workshop in Theoretical Physics, Budapest, Hungary, 1-3 August 200

Improving the improved action

We investigate the construction of improved actions by the Monte Carlo Renormalization Group method in the context of SU(2) gauge theory utilizing different decimation procedures and effective actions. We demonstrate that the basic self-consistency requirement for correct application of MCRG, i.e. that the decimated configurations are equilibrium configurations of the adopted form of the effective action, can only be achieved by careful fine-tuning of the choice of decimation prescription and/or action.Comment: 8 pages, 5 figure

Decomposition of entanglement entropy in lattice gauge theory

We consider entanglement entropy between regions of space in lattice gauge theory. The Hilbert space corresponding to a region of space includes edge states that transform nontrivially under gauge transformations. By decomposing the edge states in irreducible representations of the gauge group, the entropy of an arbitrary state is expressed as the sum of three positive terms: a term associated with the classical Shannon entropy of the distribution of boundary representations, a term that appears only for non-Abelian gauge theories and depends on the dimension of the boundary representations, and a term representing nonlocal correlations. The first two terms are the entropy of the edge states, and depend only on observables measurable at the boundary. These results are applied to several examples of lattice gauge theory states, including the ground state in the strong coupling expansion of Kogut and Susskind. In all these examples we find that the entropy of the edge states is the dominant contribution to the entanglement entropy.Comment: 8 pages. v2: added references, expanded derivation, matches PRD versio