2007/08/31 by J. O'Dwyer, J. O’Dwyer, H. Osborn · 1 citation
Physics and Astronomy · #Asymptotic expansion #Black Holes and Theoretical Physics #Critical exponent #Exact solutions in general relativity #Fixed point #Multicritical point #Nonlinear Waves and Solitons #Nonlinear system #Quantum Chromodynamics and Particle Interactions #Renormalization group #Scalar (mathematics) #Series expansion #cond-mat.other #hep-th
paper · pdf · doi:10.1016/j.aop.2007.10.005
published as Annals Phys.323:1859-1898,2008 · 40 pages, 12 figures version2: small corrections, extra references, final appendix rewritten, version3: some corrections to perturbative calculations
openalex publication_date 2007/10/29 · openalex created_date 2016/06/24 · arxiv created 2020/05/29 · arxiv updated 2020/06/01 · openalex updated_date 2026/08/05
The Polchinski version of the exact renormalisation group equations is applied to multicritical fixed points, which are present for dimensions between two and four, for scalar theories using both the local potential approximation and its extension, the derivative expansion. The results are compared with the epsilon expansion by showing that the non linear differential equations may be linearised at each multicritical point and the epsilon expansion treated as a perturbative expansion. The results for critical exponents are compared with corresponding epsilon expansion results from standard perturbation theory. The results provide a test for the validity of the local potential approximation and also the derivative expansion. An alternative truncation of the exact RG equation leads to equations which are similar to those found in the derivative expansion but which gives correct results for critical exponents to order ε and also for the field anomalous dimension to order ε2. An exact marginal operator for the full RG equations is also constructed.