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The axial anomaly and the lattice Dirac sea

Ambjørn, J. ; Greensite, J. and Peterson, C. LU (1983) In Nuclear Physics, Section B 221(2). p.381-408
Abstract

In the hamiltonian formulation of fermions coupled to external gauge fields, the axial anomaly has a simple physical interpretation in terms of level shifting at the top of the Dirac sea. We apply this formalism to lattice QED in 1 + 1 and 3 + 1 dimensions, in order to study how the lattice regulation and small fermion mass affect the picture. For a simple choice of the E and B fields, it is possible to accurately follow the time evolution of the (lattice) Dirac sea of Wilson fermions. We find that the Wilson r term plays a role, with respect to the anomaly, which is closely analogous to point-splitting in the continuum. This role is jeopardized whenever the Wilson mass scale r/a is comparable to other physical mass scales in the... (More)

In the hamiltonian formulation of fermions coupled to external gauge fields, the axial anomaly has a simple physical interpretation in terms of level shifting at the top of the Dirac sea. We apply this formalism to lattice QED in 1 + 1 and 3 + 1 dimensions, in order to study how the lattice regulation and small fermion mass affect the picture. For a simple choice of the E and B fields, it is possible to accurately follow the time evolution of the (lattice) Dirac sea of Wilson fermions. We find that the Wilson r term plays a role, with respect to the anomaly, which is closely analogous to point-splitting in the continuum. This role is jeopardized whenever the Wilson mass scale r/a is comparable to other physical mass scales in the problem, as is the case, for example, in strong coupling calculations. Remarkably, we find that hadronic scales of only a few lattice spacings are probably sufficient to guarantee the proper anomaly structure.

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author
; and
publishing date
type
Contribution to journal
publication status
published
in
Nuclear Physics, Section B
volume
221
issue
2
pages
28 pages
publisher
North-Holland
external identifiers
  • scopus:0000333095
ISSN
0550-3213
DOI
10.1016/0550-3213(83)90585-0
language
English
LU publication?
no
id
fd3c7d21-2c60-4748-8323-4350625c343a
date added to LUP
2019-05-14 16:56:00
date last changed
2021-10-10 04:41:15
@article{fd3c7d21-2c60-4748-8323-4350625c343a,
  abstract     = {{<p>In the hamiltonian formulation of fermions coupled to external gauge fields, the axial anomaly has a simple physical interpretation in terms of level shifting at the top of the Dirac sea. We apply this formalism to lattice QED in 1 + 1 and 3 + 1 dimensions, in order to study how the lattice regulation and small fermion mass affect the picture. For a simple choice of the E and B fields, it is possible to accurately follow the time evolution of the (lattice) Dirac sea of Wilson fermions. We find that the Wilson r term plays a role, with respect to the anomaly, which is closely analogous to point-splitting in the continuum. This role is jeopardized whenever the Wilson mass scale r/a is comparable to other physical mass scales in the problem, as is the case, for example, in strong coupling calculations. Remarkably, we find that hadronic scales of only a few lattice spacings are probably sufficient to guarantee the proper anomaly structure.</p>}},
  author       = {{Ambjørn, J. and Greensite, J. and Peterson, C.}},
  issn         = {{0550-3213}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{2}},
  pages        = {{381--408}},
  publisher    = {{North-Holland}},
  series       = {{Nuclear Physics, Section B}},
  title        = {{The axial anomaly and the lattice Dirac sea}},
  url          = {{http://dx.doi.org/10.1016/0550-3213(83)90585-0}},
  doi          = {{10.1016/0550-3213(83)90585-0}},
  volume       = {{221}},
  year         = {{1983}},
}