Thermodynamically stable phases of asymptotically flat Lovelock black holes

Abstract We present the first examples of phase transitions in asymptotically flat black hole solutions. analyse thermodynamic properties holes order N ⩾ 3 Lovelock gravity, with zero cosmological constant. find a new type ‘inverted’ swallowtail indicative stable temperature regions for an otherwise unstable neutral hole, and demonstrate multiple such phases can exist coexist at multi-critical points. also that charged holes, ordinary swallowtails on Gibbs free energy branch, allowing as seen anti-de Sitter (AdS) holes. A triple point N = 5 quadruple 7 are presented explicitly. investigate changes lowest constant is varied, draw comparisons to pressure AdS systems.