Wednesday, September 11, 2013

Global and local aspects of causality in quantum mechanics

It contains my talk to the conference "The Time Machine Factory, [speakable, unspeakable] on Time Travel in Turin", (Turin, Italy, October 14-19, 2012). The conference was very well organized, and the list of participants was really impressive. The proceedings were recently published online at EPJ Web of Conferences. Here is the link to my paper, and to the arXiv version. Here is a link to the slides.

Quantum mechanics forces us to reconsider certain aspects of classical causality. The 'central mystery' of quantum mechanics manifests in different ways, depending on the interpretation. This mystery can be formulated as the possibility of selecting part of the initial conditions of the Universe 'retroactively'. This talk aims to show that there is a global, timeless, 'bird's view' of the spacetime, which makes this mystery more reasonable. We will review some well-known quantum effects from the perspective of global consistency.

This picture (which I made for the slides) represents the directions used in the proof to the Kochen–Specker theorem, simplified by A. Peres, and arranged by R. Penrose in a pattern inspired by M. C. Escher's Waterfall.

This paper develops some of the ideas I presented in my essay, "The Tao of It and Bit", which qualified for the finals of the FQXi essay contest  "It from Bit or Bit from It?", 2013.


Unknown said...

So this may seem crazy - but the image against your abstract prompted me to sit upright with surprise. Your picture is uncannily similar to something in indian/hindu theology/mythology commonly referred to as 'yantra'.

Check the images against

Cristi Stoica said...

Symmetry seems to nourish our desire to find simple laws governing the complex world. It plays a tremendous role in physics, not only in arts. Some saw in symmetry a way to encode, and to make accessible, the very essence of various religious or philosophical principles.

In the present case, unlike other cases in physics, the symmetry emerged from the simplified proof of a theorem. The solution with 33 directions could be arranged in such a symmetric form. The original version, using 117 directions, and the version with the minimum number of directions, 31, are not that symmetric.

If you are interested in symmetry, maybe you will like this post.