University of Swansea
Friday, April 19, 2013 - 17:15
Building 54 (Maths) Lecture Theatre 5A
Torelons and their string description
The question of which effective string theory describes the confining flux-tube has been a subject of extensive investigation during the last two decades. We extracted by means of numerical simulations using lattice techniques the spectrum of confining SU(N) torelons (flux-tubes that wind around a spatial torus) of variable length L, in 2+1 and 3+1 dimensions, in the fundamental representation of colour and for several combinations of parity and longitudinal momentum. We compare the energies of the low-lying states to the free string Nambu-Goto model and to recent results on the universal properties of effective string actions. The main aim of this talk will be to provide convincing evidence that Nambu-Goto string is the best known description for the confining fundamental flux-tube in 2+1 and 3+1 dimensions. I am planning to spend most of the time demonstrating our results for 2+1 dimensions since this is a much less complicated case than that for 3+1 dimensions. For 3+1 dimensions I will only provide a brief summary of our findings most of which resemble those in 2+1 dimensions apart from some states with particular quantum numbers which have large deviations from Nambu-Goto. Finally, and if there is time left, I will present our very recent results on the spectrum of 2+1 dimensional closed flux-tubes in higher irreducible-representations of colour.