Neumann scalars in AdS: partition functions and phases

Abstract

We present an analysis of one-loop partition functions for scalars in AdS$_{d+1}$ obeying the Neumann boundary condition and explore phases of scalar field theories in several dimensions at zero and finite temperature. The partition function computation involves an analytic continuation from $Δ_+$ corresponding to the Dirichlet boundary condition to $Δ_-$ corresponding to Neumann boundary condition. We show that this can be implemented by deformations of the contour for integral over eigenvalue ($λ$) of the Laplace operator as compared to the integral over ${\mathbb R}$ in [arXiv:2201.09043] for the Dirichlet boundary condition. We further contrast these phases with those appearing for the case of scalars obeying the Dirichlet boundary condition and corroborate the occurrence of these phases by studying the long range behaviour of correlators.