60 citations · 341 across the 20 of their papers we have counts for
20 papers
States of Low Energy on Bianchi I spacetimes
Rudrajit Banerjee, Max Niedermaier
States of Low Energy are a class of exact Hadamard states for free quantum fields on cosmological spacetimes whose structure is fixed at {\it all} scales by a minimization principl…
The spatial Functional Renormalization Group and Hadamard states on cosmological spacetimes
Rudrajit Banerjee, Max Niedermaier
A spatial variant of the Functional Renormalization Group (FRG) is introduced on (Lorentzian signature) globally hyperbolic spacetimes. Through its perturbative expansion it is arg…
Temporal breakdown and Borel resummation in the complex Langevin method
A. Duncan, M. Niedermaier
We reexamine the Parisi-Klauder conjecture for complex e^{iθ/2} ϕ^4 measures with a Wick rotation angle 0 <= θ/2 < π/2 interpolating between Euclidean and Lorentzian signature. Our…
Perturbative and nonperturbative correspondences between compact and non-compact sigma-models
Max Niedermaier, Erhard Seiler, Peter Weisz
Compact (ferro- and antiferromagnetic) sigma-models and noncompact (hyperbolic) sigma-models are compared in a lattice formulation in dimensions . While the ferro- and an…
Structure of the space of ground states in systems with non-amenable symmetries
M. Niedermaier, E. Seiler
We investigate classical spin systems in dimensions whose transfer operator commutes with the action of a nonamenable unitary representation of a symmetry group, here ${\…
Vacuum orbit and spontaneous symmetry breaking in hyperbolic sigma models
A. Duncan, M. Niedermaier, E. Seiler
We present a detailed study of quantized noncompact, nonlinear SO(1,N) sigma-models in arbitrary space-time dimensions D \geq 2, with the focus on issues of spontaneous symmetry br…