Lattice simulations of real-time quantum fields
- Institute for Nuclear Physics, Darmstadt University of Technology, Schlossgartenstr. 9, 64289 Darmstadt (Germany)
- Institute for Theoretical Physics, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)
We investigate lattice simulations of scalar and non-Abelian gauge fields in Minkowski space-time. For SU(2) gauge-theory expectation values of link variables in 3+1 dimensions are constructed by a stochastic process in an additional (5th) 'Langevin-time'. A sufficiently small Langevin step size and the use of a tilted real-time contour leads to converging results in general. All fixed point solutions are shown to fulfil the infinite hierarchy of Dyson-Schwinger identities, however, they are not unique without further constraints. For the non-Abelian gauge theory the thermal equilibrium fixed point is only approached at intermediate Langevin-times. It becomes more stable if the complex time path is deformed towards Euclidean space-time. We analyze this behavior further using the real-time evolution of a quantum anharmonic oscillator, which is alternatively solved by diagonalizing its Hamiltonian. Without further optimization stochastic quantization can give accurate descriptions if the real-time extent of the lattice is small on the scale of the inverse temperature.
- OSTI ID:
- 21011100
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 75, Issue 4; Other Information: DOI: 10.1103/PhysRevD.75.045007; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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