Existence Of Cosmological Horizon Research Articles

TIME AND IRREVERSIBILITY IN AN ACCELERATING UNIVERSE

It is a remarkable fact that all processes occurring in the observable universe are irreversible, whereas the equations through which the fundamental laws of physics are formulated are invariant under time reversal. The emergence of irreversibility from the fundamental laws has been a topic of consideration by physicists, astronomers and philosophers since Boltzmann's formulation of his famous "H" theorem. In this paper, we shall discuss some aspects of this problem and its connection with the dynamics of spacetime, within the framework of modern cosmology. We conclude that the existence of cosmological horizons allows a coupling of the global state of the universe with the local events determined through electromagnetic processes.

THE IMPLICATIONS OF A COSMOLOGICAL INFORMATION BOUND FOR COMPLEXITY, QUANTUM INFORMATION AND THE NATURE OF PHYSICAL LAW

The finite age of the universe and the existence of cosmological horizons provides a strong argument that the observable universe represents a finite causal region with finite material and informational resources. A similar conclusion follows from the holographic principle. In this paper I address the question of whether the cosmological information bound has implications for fundamental physics. Orthodox physics is based on Platonism: the laws are treated as infinitely precise, perfect, immutable mathematical relationships that transcend the physical universe and remain totally unchanged by physical processes, however extreme. If instead the laws of physics are regarded as akin to computer software, with the physical universe as the corresponding hardware, then the finite computational capacity of the universe imposes a fundamental limit on the precision of the laws and the specifiability of physical states. That limit depends on the age of the universe. I examine how the imprecision of the laws impacts on the evolution of highly entangled states and on the problem of dark energy.

A Brief Comment on Instanton-like Singularities and Cosmological Horizons

We argue that in the presence of instanton-like singularities, the existence of cosmological horizons can become frame-dependent, ie. a horizon which appears in Einstein frame may not appear in string frame. We speculate on the relation between instanton-like singularities and the formulation of quantum gravity in de Sitter space.