The Amplituhedron: Quantum Physics Decoded

amplutihedron_spanScientists recently made a major breakthrough that may completely alter our perceptions of quantum physics, and the nature of the universe itself. After many decades of trying to reformulate quantum field theory, scientists at Harvard University discovered of a jewel-like geometric object that they believe will not only simplify quantum science, but even challenge the notion that space and time are fundamental components of reality.

This jewel has been named the “amplituhedron”, and it is radically simplifying how physicists calculate particle interactions. Previously, these Interactions were calculated using quantum field theory – mathematical formulas that were thousands of terms long. Now, these interactions can be described by computing the volume of the corresponding amplituhedron, which yields an equivalent one-term expression.

theory_of_everythingJacob Bourjaily, a theoretical physicist at Harvard University and one of the researchers who developed the new idea, has this to say about the discovery:

The degree of efficiency is mind-boggling. You can easily do, on paper, computations that were infeasible even with a computer before.

This is exciting news, in part because it could help facilitate the search for a Grand Unifying Theory (aka. Theory of Everything) that manages to unify all the fundamental forces of the universe. These forces are electromagnetism, weak nuclear forces, strong nuclear forces, and gravity. Thus far, attempts at resolving these forces have run into infinities and deep paradoxes.

gravityWhereas the field of quantum physics has been able to account for the first three, gravity has remained explainable only in terms of General Relativity (Einstein’s baby). As a result, scientists have been unable to see how the basic forces of the universe interact on a grand scale, and all attempts have resulted in endless infinities and deep paradoxes.

The amplituhedron, or a similar geometric object, could help by removing two deeply rooted principles of physics: locality and unitarity. Locality is the notion that particles can interact only from adjoining positions in space and time, while unitarity holds that the probabilities of all possible outcomes of a quantum mechanical interaction must add up to one.

quantum_field_theoryThe concepts are the central pillars of quantum field theory in its original form, but in certain situations involving gravity, both break down, suggesting neither is a fundamental aspect of nature. As Nima Arkani-Hamed – a professor of physics at the Institute for Advanced Study in Princeton, N.J. and the lead author of the new work – put it: “Both are hard-wired in the usual way we think about things. Both are suspect.”

In keeping with this idea, the new geometric approach to particle interactions removes locality and unitarity from its starting assumptions. The amplituhedron is not built out of space-time and probabilities; these properties merely arise as consequences of the jewel’s geometry. The usual picture of space and time, and particles moving around in them, is a construct.

Photon_follow8And while the amplituhedron itself does not describe gravity, Arkani-Hamed and his collaborators think there might be a related geometric object that does. Its properties would make it clear why particles appear to exist, and why they appear to move in three dimensions of space and to change over time. This is because, as Bourjaily put it:

[W]e know that ultimately, we need to find a theory that doesn’t have [unitarity and locality]. It’s a starting point to ultimately describing a quantum theory of gravity.

Imagine that. After decades of mind-boggling research and attempts at resolving the theoretical issues, all existence comes down to a small jewel-shaped structure. I imagine the Intelligent Design people will have a field day with this, and I can foresee it making it into the new season of Big Bang Theory as well. Breakthroughs like this always do seem to have a ripple effect…

Source: simonsfoundation.org

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