The Edge states of the BF system and the London equations

May, 1992
38 pages
Published in:
  • Int.J.Mod.Phys.A 8 (1993) 723-752
e-Print:
Report number:
  • SU-4240-507

Citations per year

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Abstract:
It is known that the 3d Chern-Simons interaction describes the scaling limit of a quantum Hall system and predicts edge currents in a sample with boundary, the currents generating a chiral U(1)U(1) Kac-Moody algebra. It is no doubt also recognized that in a somewhat similar way, the 4d BFBF interaction (with BB a two form, dBdB the dual  j~*j of the eletromagnetic current, and F the electromagnetic field form) describes the scaling limit of a superconductor. We show in this paper that there are edge excitations in this model as well for manifolds with boundaries. They are the modes of a scalar field with invariance under the group of diffeomorphisms (diffeos) of the bounding spatial two-manifold. Not all of this group seem implementable by operators in quantum theory, the implementable group being a subgroup of volume preserving diffeos. The BFBF system in this manner can lead to the w1+w_{1+\infty } algebra and its variants. Lagrangians for fields on the bounding manifold which account for the edge observables on quantization are also presented. They are the analogues of the 1+11+1 dimentional massless scalar field Lagrangian describing the edge modes of an abelian Chern-Simons theory with a disk as the spatial manifold. We argue that the addition of ``Maxwell'' terms constructed from F FF\wedge ~*F and dB dBdB\wedge ~*dB do not affect the edge states, and that the augmented Lagrangian has an infinite number of conserved charges- the aforementioned scalar field modes- localized at the edges. This Lagrangian is known to describe London equations and a massive vector field. A (3+1)(3+1) dimensional generalization of the Hall effect involving vortices coupled to BB is also proposed.
Note:
  • 38 pages
  • gauge field theory: U(1)
  • gauge field theory: tensor
  • dimension: 3
  • Hall effect
  • quantization
  • Hamiltonian formalism
  • model: superconductivity
  • superconductivity: model
  • algebra: Kac-Moody
  • algebra: W(infinity)