It is well known that a static quark-antiquark pair has a spectrum of flux-tube excitations in a pure gauge theory. In this talk I will show numerically that, in a variety of gauge Higgs theories in the non-confining Higgs phase, there is also a spectrum of excitations of the gauge and Higgs fields surrounding a static fermion-antifermion pair. These are localized and stable excitations which...
Exclusive processes are traditionally described by perturbative hard blocks and
``distribution amplitudes" (DAs), matrix elements of operators of various chiral structure
and twist. One paper (with I.Zahed) calculate instanton contribution to hard blocks, which is
found comparable to perturbative one in few-$GeV^2$ $Q^2$ region of interest. Another paper
aims at comprehensive wave...
When non-Abelian gauge fields in $SU(3)$ QCD have a line-singularity leading to non-commutability with respect to successive partial-derivative operations, the non-Abelian Bianchi identity is violated. The violation as an operator is shown to be equivalent to violation of the Abelian-like Bianchi identities. Then there appear eight Abelian-like conserved magnetic monopoles of the Dirac type in...
We study the free energies of individual quarks in a finite volume with suitable boundary conditions to account for their $Z_3$-valued electric flux. In order to demonstrate how 't Hooft's electric fluxes can be used to account for Gauss' law, we first use a $Z_3$-Potts model as an effective Polyakov-loop theory for the heavy-dense limit of QCD at strong coupling, with interfaces to realize 't...
I discuss the relation between coupling a TQFT to Yang-Mills theory, resurgence and Lefschetz thimble decomposition. To classify the non-perturbative effects in original SU(N) theory, one must use PSU(N) bundle and lift configurations (critical points at infinity) for which there is no obstruction back to SU(N). These provide a refinement of instanton sums: integer topological charge, but...
We analyse the properties of thermal monopoles in the high temperature phase of QCD with N_f = 2+1 flavours and physical quark masses. In particular, we determine the temperature where monopoles show condensation properties similar to those already studied in pure gauge Yang-Mills theories and related to the onset of confinement, comparing it with the temperature where chiral symmetry...
We discuss the effects of rotation on confining properties of gauge theories focusing on compact electrodynamics in two spatial dimensions as an analytically tractable model. We show that the rotation leads to a deconfining transition at finite temperature starting from a certain distance from the rotation axis. We argue that the uniformly rotating confining system possesses, in addition to...
Decomposition of SU(2) gauge field into monopole and monopoleless components is studied in SU(2) gluodynamics and in QC_2D with nonzero quark chemical potential after fixing MA gauge. For both components we calculate respective static potential and compare their sum with the nonabelian static potential. We demonstrate good agreement in the confinement phase and discuss the implications of our results.
String tension is one of the characteristic quantity in confining gauge theories. In SU(N) gauge theories, there is a center symmetry, or $\mathbb{Z}_N$ 1-form symmetry, which acts on the test quarks, and this is the symmetry which controls the spectral properties of confining strings in the infrared regime. This is sometimes called as an $N$-ality rule.
In this talk, I will talk about some...
Quark confinement mechanism is one of unsolved important problems. In the dual Meissner picture of color confinement, it is considered that the color flux tube between static quarks is caused by the condensation of color magnetic monopoles in the QCD vacuum. In this talk, we show new results of the dual Meissner effect due to the violation of non-Abelian Bianchi identity corresponding to...
When investigating confinement in the Coulomb gauge on the lattice, one encounters some difficulties in devising a suitable definition of the dispersion relations for Wilson fermions. In this talk we will discuss a solution to this problems based on a redefinition of the lattice physical momentum of the fermion.
The $SU(2)$ Lattice Gauge Theory in $(2+1)$ dimensions is a perfect laboratory to study the fine details of the confining interquark potential. In this talk I will first discuss a few important properties of the effective string theory and then I will compare its predictions with the results of some recent high precision montecarlo simulations of the $SU(2)$ LGT, looking for possible...
The vacuum of quantum chromodynamics has an incredibly rich structure at the confinement scale, which is intimately connected with the topology of gauge fields, and put to a stringent test by the strong CP problem. We investigate the long distance properties of the theory in the presence of a topological $\theta$ term. This is done on the lattice, using the gradient flow to isolate the long...
In this work, we shall analyze mixed ensembles formed by percolating oriented
and nonoriented center-vortices in three and four dimensions. In particular, we suggest that the inclusion of the natural interactions and possible matching rules are responsible for the emergence of topological solitons that accommodate an asymptotic Casimir scaling law and the observed flux tube profiles.
Confinement remains one the most interesting and challenging nonperturbative phenomenon in non-Abelian gauge theories. Recent semiclassical (for $SU(2)$) and lattice (for QCD) studies have suggested that confinement arises from interactions of statistical ensembles of instanton-dyons with the Polyakov loop. In this talk, I will present recent work which has extended the study of semiclassical...
