We formulate a non-perturbative lattice model of two-dimensional Lorentzian quantum
gravity by performing the path integral over geometries with a causal structure. The model …

We review some recent attempts to extract information about the nature of quantum gravity,
with and without matter, by quantum field theoretical methods. More specifically, we work …

In the last Part, entitled “Beyond the Horizon”, I am going to discuss conceptual issues and
the foundations of theoretical physics. I shall try to outline a broader¹ view of the theoretical …

We formulate a first order action principle in a higher dimensional space MN in which we
embed spacetime. The action I is essentially an “area” of a four-dimensional spacetime V 4 …

We make a conceptual overview of a particular approach to the initial-value problem in
canonical gauge theories. We stress how the first-class phase-space constraints may be …

A new theory is considered according to which extended objects in n-dimensional space are
described in terms of multivector coordinates which are interpreted as generalizing the …

As time is not an observable, we use Fisher information (FI) to address the problem of time.
We demonstrate that although the Hamiltonian operator is the generator of time, the …

We consider quantization of the Baierlein-Sharp-Wheeler form of the gravitational action, in
which the lapse function is determined from the Hamiltonian constraint. This action has a …

Starting from the geometric calculus based on Clifford algebra, the idea that physical
quantities are Clifford aggregates (“polyvectors”) is explored. A generalized point particle …

The classical field equations of general relativity can be expressed as a single geodesic
equation, describing the free fall of a point particle in superspace. Based on this formulation …