Holographic RG flows and AdS₅ black strings from 5D half-maximal gauged supergravity

We study five-dimensional N =4 gauged supergravity coupled to five vector multiplets with compact and non-compact gauge groups U(1) x SU(2) x SU(2) and U(1) x SO(3, 1). For U(1) x SU(2) x SU(2) gauge group, we identify N = 4 AdS₅ vacua with U(1) x SU(2) x SU(2) and U(1) x SU(2)_diag symmetries and analytically construct the corresponding holographic RG flow interpolating between these critical points. The flow describes a deformation of the dual N = 2 SCFT driven by vacuum expectation values of dimension-two operators. In addition, we study AdS₃ x Σ₂ geometries, for Σ₂ being a two-sphere S² or a two-dimensional hyperbolic space H², dual to twisted compactifications of N = 2 SCFTs with flavor symmetry SU(2). We find a number of AdS₃ x H² solutions preserving eight supercharges for different twists from U(1) x U(1) x U(1) and U(1) x U(1)_diag gauge fields. We numerically construct various RG flow solutions interpolating between N = 4 AdS₅ critical points and these AdS₃ x H² geometries in the IR. The solutions can also be interpreted as supersymmetric black strings in asymptotically AdS₅ space. These types of holographic solutions are also studied in non-compact U(1) x SO(3, 1) gauge group. In this case, only one N = 4 AdS₅ vacuum exists, and we give an RG flow solution from this AdS₅ to a singular geometry in the IR corresponding to an N = 2 non-conformal field theory. An AdS₃ x H² solution together with an RG flow between this vacuum and the N = 4 AdS₅ are also given. (orig.)