A Hospitable Universe by Rodolfo Gambini & Jorge Pullin

Author:Rodolfo Gambini & Jorge Pullin
Language: eng
Format: epub
Tags: philosophy of science, physics, quantum physics, cosmology, biology, universe, consciousness, natural religiousness, Spinoza, theology, religion, emergence, naturalism, physicalism, epistemology, reductionism, ontology, religious naturalism, electromagnetism, Faraday, Maxwell, atomism, space-time, spacetime, relativity, special relativity, matter, uncertainty principle, wave functions, wavefunctions
ISBN: 9781845409760
Publisher: Andrews UK Limited 2018
Published: 2018-04-25T00:00:00+00:00

9.5.3 The (real time) Montevideo Interpretation of quantum mechanics

The closest we have to an explanation for the measurement process within the quantum theory is what is called environmental decoherence. It is based on the fact that when a quantum system interacts with an environment with an enormous number of (microscopic) degrees of freedom, the state of the quantum system suffers transitions that “almost” look like the abrupt evolutions one needs to postulate in measurements that we have discussed in some detail at the end of Chapter 6. However, even if they are difficult to detect, quantum superpositions are still present hidden in the environment and may be in principle observed. Environmental decoherence is important because the measurement processes involve interactions with macroscopic systems with many degrees of freedom that always interact with their environment. Interactions with the environment were neglected for decades and the relevance of this effect was only recognized in the 1980s. It is problematic to consider that environmental decoherence explains the measurement process because the information about the superposition of the quantum system remains hidden in the environment and may in principle be recovered. This is contradictory with the assumption that the measuring device takes a definite value, that is has the needle pointing in a definite direction.

A new interpretation was recently proposed that explains why these hidden superpositions are destroyed. The novelty of this interpretation of quantum mechanics is the inclusion in the quantum description of another factor up to now neglected. In the standard Schrödinger description of the evolution, time is treated as a classical external parameter, but time is actually measured by physical clocks that obey quantum mechanical laws. Quantum measurements of time have a limited precision. This limitation arises from quantum fluctuations and gravitational effects like the formation of black holes and time delays and has a fundamental nature (Salecker and Wigner 1958, Ng and van Dam 1995, Frenkel 2010). This effect, first noticed more than 50 years ago has been recently confirmed by many authors. We have shown that a quantum mechanical treatment of time (Gambini et al. 2009) combined with fundamental limitations of measurements stemming from general relativity, lead to a modified Schrödinger evolution that allows transitions between quantum superpositions and statistical mixtures.

When one takes into account the limitations in measurement imposed by quantum mechanics and gravity, the states resulting from decoherence become indistinguishable from those produced by the measurement postulate. The “almost” of the standard approach to decoherence is removed by fundamental limitations predicted by the theory itself and the transitions from superpositions to statistical mixtures required to explain measurements are deduced. This in turn supplies an objective criterion that says when and what events may occur. Events occur when the state of a system resulting from a full quantum mechanical evolution becomes a statistical mixture (Gambini et al. 2010/2011/2015). The transition to the statistical mixture of the system plus environment state gives necessary and sufficient conditions for the occurrence of events. Events are assumed to occur as

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