The implications of a holographic universe for quantum information science and the nature of physical law - P.C.W. Davies (15p).pdf

The implications of a holographic universe for quantum
information science and the nature of physical law



. Davies
Australian Centre for Astrobiology, Macquarie University, NSW 2109, Australia

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Abstract

Several lines of evidence suggest that the total information content of the observable
universe is bounded by a finite number given by the area of a cosmological surface
divided by the Planck area. This is referred to as the holographic principle. The current
bound is roughly 10122 bits, but in the past it was smaller, varying like t2 in the early
universe. Although the bound is too large today to affect most of everyday physics, it
does have profound implications for plex systems and for cosmology. For
example, the project to build a useful puter, which is projected to exploit
states possessing plexity, comes into conflict with the information bound
at a level of entanglement of about 400 qubits, suggesting a breakdown of unitary
evolution at this threshold, possibly associated with the emergence of classicality. If the
information bound is applied to the quantum vacuum, it yields an energy density close to
the observed density of cosmological dark energy. However, because the bound is time-
dependent, the vacuum energy will vary in time too, and consistency with energy
conservation then demands that G or c varies with time over cosmological time scales.
Further sweeping implications follow if one adopts the philosophy that information is
primary (‘the universe is puter’), and that the laws of physics do not exist in a
transcendent Platonic realm of perfect mathematical forms and operations, as is
conventionally supposed, but are fundamentally tied to the real physical universe, with its
finite age and resources, and subject to the holographic information bound. I suggest a
generalization of the information bound based on this point of view, formulated in ter