1. Lattice implementation of Abelian gauge theories with Chern–Simons number and an axion field.
- Author
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Figueroa, Daniel G. and Shaposhnikov, Mikhail
- Subjects
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CRYSTAL lattices , *GAUGE field theory , *CHERN-Simons gauge theory , *AXIONS , *PARTICLE physics , *QUARK-gluon plasma - Abstract
Real time evolution of classical gauge fields is relevant for a number of applications in particle physics and cosmology, ranging from the early Universe to dynamics of quark–gluon plasma. We present an explicit non-compact lattice formulation of the interaction between a shift -symmetric field and some U ( 1 ) gauge sector, a ( x ) F μ ν F ˜ μ ν , reproducing the continuum limit to order O ( d x μ 2 ) and obeying the following properties: (i) the system is gauge invariant and (ii) shift symmetry is exact on the lattice. For this end we construct a definition of the topological number density K = F μ ν F ˜ μ ν that admits a lattice total derivative representation K = Δ μ + K μ , reproducing to order O ( d x μ 2 ) the continuum expression K = ∂ μ K μ ∝ E → ⋅ B → . If we consider a homogeneous field a ( x ) = a ( t ) , the system can be mapped into an Abelian gauge theory with Hamiltonian containing a Chern–Simons term for the gauge fields. This allow us to study in an accompanying paper the real time dynamics of fermion number non-conservation (or chirality breaking) in Abelian gauge theories at finite temperature. When a ( x ) = a ( x → , t ) is inhomogeneous, the set of lattice equations of motion do not admit however a simple explicit local solution (while preserving an O ( d x μ 2 ) accuracy). We discuss an iterative scheme allowing to overcome this difficulty. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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