Exact black holes in quadratic gravity with any cosmological constant

Understand

We present a new explicit class of black holes in general quadratic gravity with a cosmological constant.

• These spherically symmetric Schwarzschild-Bach-(anti-)de Sitter geometries (Schwa-Bach-(A)dS), derived under the assumption of constant scalar curvature, form a three-parameter family determined by the black-hole horizon position, the value of Bach invariant on the horizon, and the cosmological constant.
• Using a conformal to Kundt metric ansatz, the fourth-order field equations simplify to a compact autonomous system.
• Its solutions are found as power series, enabling us to directly set the Bach parameter and/or cosmological constant equal to zero.