Decomposition of the static potential in the Maximal Abelian gauge

Decomposition of SU(2) gauge field into monopole and monopoleless components is studied in SU(2) gluodynamics and in QC2D with zero and 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.

The Debye length and the running coupling of QCD: A potential and phenomenological approach

In this paper, one uses a damped potential to present a description of the running coupling constant of QCD in the confinement phase. Based on a phenomenological perspective for the Debye screening length, one compares the running coupling obtained here with both the Brodsky–de Téramond–Deur and the Richardson approaches. The results seem to indicate the model introduced here corroborate the Richardson approach. Moreover, the Debye screening mass in the confinement phase depends on a small parameter, which tends to vanish in the nonconfinement phase of QCD.

A Harm Reduction Approach to the Ethical Management of the COVID-19 Pandemic

The post-confinement phase of the COVID-19 pandemic will require that governments navigate more complex ethical questions than had occurred in the initial, ‘curve-flattening’ phase, and that will occur when the pandemic is in the past. By looking at the unavoidable harms involved in the confinement and quarantine methods employed during the initial phase of the pandemic, we can develop a harm reduction approach to managing the phase during which society will be gradually reopened in a context of managed risk. The principles that are at the heart of such an approach include a reckoning with all of the harms involved in policy choice, including harms that might be given rise to by policy implementation itself; a focus on the harms to which already vulnerable populations are susceptible; and a strong preference for policies that economize on the use of prohibitions and of coercive state enforcement, and that instead emphasize the agency of citizens in realizing health-promoting behavior change. This framework is applied to a policy proposal that has been discussed in policy circles in a number of countries, that of immunity ‘passports’, and to policies that emphasize the creative use of space and time to achieve physical distancing goals.

Fully Quantum String Representation of a Wilson Loop in the Finite-Temperature 3D Yang–Mills Theory

We demonstrate the emergence of the Polchinski–Strominger term in the string representation of a Wilson loop in the confinement phase of the finite-temperature 3D Yang–Mills theory. At a temperature which is roughly twice smaller than the deconfinement critical temperature, the value of the coupling of that term becomes such that the string conformal anomaly cancels out, thereby admitting a fully quantum description of the quark–antiquark string in 3D rather than 26D.

The far-field limit profile functions of two overlapped dyons

We study the profile functions of two overlapped dyons at infinity. We assume that the superposition of two dyons satisfies the Yang–Mills (Y–M) equation and then we find new equations of motion for individual dyons which no longer satisfy the original Y–M equation. By solving these new equations we find that the profile functions of two overlapped dyons of the same type at infinity look like the profile functions of one dyon. However, the superposition of two dyons of different types gives a trivial holonomy and therefore no contribution in the confinement phase is observed.