“Is our universe extremely unnatural, a strange permutation?” (Weekend Feature)

The universe

“Is our universe extremely unnatural, a strange permutation among innumerable other possibilities, observed for the sole reason that its special conditions allowed life to arise, or are the properties of the universe inevitable, predictable, that is, ‘natural’? joining in a sensible pattern? This is the question, the great unknownWhat worries the theoretical physicist? Nima Arkani Hamedprofessor at the Institute for Advanced Study (IAS) in Princeton, NJ

Beyond space-time and quantum physics

Arkani-Hamed takes us beyond the edge, beyond Einstein, beyond spacetime and quantum mechanics and the tropes of 20th century physics, to a spectacular new vision of the cosmos. In 2012, he won the inaugural $3 million Fundamental Physics Prize “for original approaches to outstanding problems in particle physics, including the proposal of extra large dimensions, new theories for the Higgs boson, novel realizations of supersymmetry, theories for Dark matter and the exploration of new mathematical structures in gauge theory scattering amplitudes.”

The “Participatory Universe”

Arkani-Hamed’s concern is the question that intrigued his predecessor, the great American quantum physicist John Archibald Wheeler in the last decades of his life was: “Are life and mind irrelevant to the structure of the universe, or are they fundamental to it?” Wheeler originated the notion of a “participatory” conscious universe, a cosmos in which all of us are embedded as co-creators, replacing the accepted universe “out there” that is separate from us. He suggested that the nature of reality was revealed by the strange laws of quantum mechanics. According to quantum theory, before the observation is made, a subatomic particle exists in various states, called a superposition (or, as Wheeler called it, a ‘Smoking Dragon’). Once the particle is observed, it instantly collapses into a single state.

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“Multiverse” of Universes Beyond Our Reach

A natural universe is, in principle, knowable, writes Beatrice de Gea in Quanta. But if the universe is unnatural and tuned for life, observes Arkani-Hamed, “the lucky result of a cosmic roulette wheel, then it stands to reason that there must be a vast and diverse “multiverse” of universes beyond our reach: the lifeless products of less fortuitous twists. This multiverse makes our universe impossible to fully understand on its own terms.

Amazingly tuned for life

Known elementary particles, Béatrice de Géa concludes, encoded in a 50-year-old set of equations called the “Standard Model”, lack a sensible pattern and appear astonishingly tuned for life, leading Arkani-Hamed and other particle physicists , guided by their belief in naturalness, to spend decades devising clever ways to fit the Standard Model into a larger natural pattern, while particle colliders like the Large Hadron Collider have been unable to find evidence for their shaped proposals. of supersymmetry, new particles and phenomena, “increasingly pointing towards the grim and radical perspective that naturalness is dead”.

The bane of space-time

Today, many physicists feel trapped, writes Natalie Wolfhover in The New Yorker, and see the need to reformulate the theories of modern physics in a new mathematical language. “They have a feeling,” he writes, “that they need to transcend the notion that objects move and interact in space and time. Einstein’s general theory of relativity beautifully weaves space and time into a four-dimensional fabric, known as spacetime, and equates gravity with deformations in that fabric. But Einstein’s theory and the concept of space-time collapse inside black holes and at the moment of the big bang. Space-time, in other words, may be a translation of some other description of reality that, although more abstract or unknown, may have greater explanatory power.

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Challenge space and time as fundamental components of reality

In 2013, Nima Arkani-Hamed and Jaroslav Trnka discovered a reformulation of scattering amplitudes that makes no reference to space or time, but found that the amplitudes of certain particle collisions are encoded in the volume of a jewel-like geometric object, which they called an “amptuhedron” that drastically simplifies particle interaction calculations and challenges the notion that space and time are fundamental components of reality.

Seamlessly connecting large-scale and small-scale images of the universe, the amplituhedron could help by eliminating two deeply embedded principles of physics: locality and unitarity. “Both are wired in the usual way that we think about things,” Arkani-Hamed said. “Both are suspects.”

This discovery has led them to explore this new geometric formulation of particle scattering amplitudes, in the hope that it will move away from our everyday, spacetime-bound conception of some explanatory structure of “greater” reality.

The unknown question, to which the universe is the answer

For Arkani-Hamed, the laws of nature suggest a different conception of what physics is about. “We are not building a machine that calculates the answers,” he says, “instead, we are discovering questions. The shape-changing laws of nature appear to be the answer “to an unknown mathematical question.”

“The ascension to the tenth level of the intellectual sky,” says Nima Arkani-Hamed, describing the ultimate goal of physics, “would be if we found the question to which the universe is the answer, and the nature of that question in and of in itself explains why it was possible to describe it in so many different ways.

“Now it seems that the answers are all around us. It’s the question we don’t know.”

avi esporer, Research Scientist, MIT Kavli Institute for Astrophysics and Space Research, via Institute for Advanced Study, the new yorker Y many Avi was previously a Sagan Fellow at NASA’s Jet Propulsion Laboratory (JPL)

Image Credit: Shutterstock License

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