R-separation of variables for the conformally invariant Laplace–Beltrami equation

Separation of variables and Hamiltonian formulation for the Ernst equation.

It is shown that the vacuum Einstein equations for an arbitrary stationary axisymmetric space-time can be completely separated by re-formulating the Ernst equation and its associated linear system in terms of a non-autonomous Schlesinger-type dynamical system. The conformal factor of the metric coincides (up to some explicitly computable factor) with the τ -function of the Ernst equation in the...

Is mass conformally invariant ?

By using the Garfinkle, Horowitz and Strominger black hole solutions as examples, we illustrate that, with respect to the reference action functional proposed by Hawking and Horowitz, the asymp-totic mass parameter is not invariant between two conformally related static spherically symmetric metrics.

Minimization of Conformally Invariant Energies

Solution of the Wave Equation by Separation of Variables

We are going to solve this problem in three steps. Step 1 In the first step, we find all solutions of (1) that are of the special form u(x, t) = X(x)T (t) for some function X(x) that depends on x but not t and some function T (t) that depends on t but not x. This is where the name “separation of variables” comes from. It is of course too much to expect that all solutions of (1) are of this form...

Conformally invariant bending energy for hypersurfaces

The most general conformally invariant bending energy of a closed four-dimensional surface, polynomial in the extrinsic curvature and its derivatives, is constructed. This invariance manifests itself as a set of constraints on the corresponding stress tensor. If the topology is fixed, there are three independent polynomial invariants: two of these are the straighforward quartic analogues of the...