Renormalization-group (RG) flow equations have been derived for the generalized sine-Gordon model (GSGM) and the Coulomb gas (CG) in d ≥ 3 of dimensions by means of Wegner's and Houghton's, and by way of the real-space RG approaches. The UV scaling laws determined by the leading-order terms of the flow equations are in qualitative agreement for all dimensions d ≥ 3, independent of the dimensionality, and in sharp contrast to the special case d = 2. For the 4-dimensional GSGM it is demonstrated explicitly (by numerical calculations), that the blocked potential tends to a constant effective potential in the infrared (IR) limit, satisfying the requirements of periodicity and convexity. The comparison of the RG flows for the three-dimensional GSGM, the CG, and the vortex-loop gas reveals a significant dependence on the renormalization schemes and the approximations used.PACS numbers: 11.10.Hi, 11.10.Kk
I. INTRODUCTIONThe renormalization of a two-dimensional one-component scalar field theory with a periodic self-interaction, and the two-dimensional generalized sine-Gordon model (GSGM) have been investigated for d = 2 dimensions in great detail over the last three decades [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]. Here, we only mention some of the main results:• The blocked potential for the two-dimensional GSGM tends to a constant effective potential in the IR limit, independent of the field [12,13,14].• Following the procedure proposed in [16], one can identically rewrite the partition function of the d-dimensional GSGM in the form of a d-dimensional static Coulomb gas, which we call here the equivalent Coulomb gas (ECG). For d = 2 it is well-known that the GSGM and the ECG, as well as the XY model describing classical planar spins belong to the same universality class [10]. The XY model has a dual theory in the sense of [17] that can be reformulated as a gas of topological excitations: the two-dimensional vortex gas (VG) for d = 2, and the three-dimensional vortex-loop gas (VLG) for d = 3 (see [10] and Refs. therein). For dimensions d = 2, it was shown that the ECG and the VG can be transformed into one another by an appropriate duality transformation [3,7,8,15] that inverts the temperature. Two-dimensional generalized models are well known where both the ECG and the VG are included as particular limiting cases [3,7,8,15] and are self-dual under the duality transformation.While the relations of the various models for two dimensions are well-established, those of the corresponding models for d = 3 are not completely settled (see e.g. [10]). In particular, it is not proven that the VLG and the threedimensional XY-model belong to the same class of universality. Therefore, the investigation of the renormalization of the GSGM and the ECG for d ≥ 3 dimensions is essential for a further clarification of this issue. The purpose of the present work is threefold:1. to investigate the renormalization of the GSGM for dimensions d ≥ 2 by the Wegner-Houghton renormalizationgroup (WH-RG) method [18] and to demonstrate numerically tha...