Sunday, January 02, 2011

Yakir Aharonov's World

While his name is relatively well-known in physics world, many outside physics would not know about Yakir Aharanov. Him winning the National Medal of Science in 2010 hopefully will give a bit more publicity to his work, especially the astounding Aharanov-Bohm effect.

This brief interview hopefully will provide more insight into him and his work. He certainly has a very progressive idea about how time has the potential to reveal surprises within the QM picture.

Q. Based on your work, how should we change our concept of time?

A. First let me explain how the idea came about from the properties of quantum mechanics -- the suggestion that we should change our notions of time. The basic difference between quantum mechanics and classical physics is that (in quantum physics) two physical systems in exactly the same state, initially, end up later in different state. It means we cannot predict the future exactly. We can only predict probabilities.

When I thought about it, it occurred to me that perhaps what nature or quantum mechanics is trying to tell us is, in fact, that there is already a difference between the two particles, but we can discover the difference only later, in the future. Though they're different already, there's no way to find out until you do the experiment in the future, and find the difference between the two systems.

That suggested to me that if we are trying to understand how to describe the present time, we need not only information of the past that comes to the present, but also, some information from the future (that) comes back to the present that tells us more information about the system.

That is true about micrscopic systems in the quantum domain. It suggests perhaps in some future physics, some future theory, we have now an approach to time where the present is described not only by things that happened in the past, (but things that) come back like the movie, Back to the Future -- come back to affect the present.

That's a real change in our understanding of time.


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