Stapmanns, J.Corboz, P.Mila, F.Honecker, A.Normand, B.Wessel, S.2018-12-132018-12-132018-12-132018-09-1710.1103/PhysRevLett.121.127201https://infoscience.epfl.ch/handle/20.500.14299/152713WOS:000444780900012We consider the finite-temperature phase diagram of the S = 1/2 frustrated Heisenberg bilayer. Although this two-dimensional system may show magnetic order only at zero temperature, we demonstrate the presence of a line of finite-temperature critical points related to the line of first-order transitions between the dimer-singlet and -triplet regimes. We show by high-precision quantum Monte Carlo simulations, which are sign-free in the fully frustrated limit, that this critical point is in the Ising universality class. At zero temperature, the continuous transition between the ordered bilayer and the dimer-singlet state terminates on the first-order line, giving a quantum critical end point, and we use tensor-network calculations to follow the first-order discontinuities in its vicinity.Physics, MultidisciplinaryPhysicsorder-disorder transitionexact ground-statemagnetization plateausmodeluniversalityexpansionbehaviormagnetschainfieldtext::journal::journal article::research article