Wednesday, November 21, 2018

Einstein's unified field theory dream is dead

Dennis Overbye writes in the NY Times:
Is Albert Einstein finally dead?

Yes. The old sage took his last breath and muttered his last indecipherable words, in German, on April 18, 1955. But lately he has been dying a second death, if one believes a new spate of articles and papers bemoaning the state of contemporary physics.

Never mind the recent, staggering discovery of gravitational waves: ripples in space-time that Einstein predicted a century ago, and which indicate the universe is peppered with black holes that shred and swallow stars.

No, something much deeper than gravity or quantum theory, Einstein’s other misbegotten legacy, is at stake.

More than anyone, it was Einstein who set the goal for modern science: the search for a final theory of everything, a “unified theory,” he said, that would explain why there was no other way to put together the universe than the one we seem to live in.

Or, as he famously put it, “What interests me is whether God had any choice in the creation of the world.”

Roll over, Albert.
He goes on to explain how string theory, supersymmetry, landscape, multiverse, unified field theory, etc. are all dead. Work in these directions has failed, even if many don't want to admit it. Peter Woit and Sabine Hossenfelder have comments.

Einstein's goal of a unified theory was foolish anyway.
But the amount of this dark energy is smaller than the predicted value of the cosmological constant by a factor of 1060. ...

According to them, atoms — the stuff of you, me and the stars — account for only 5 percent of the cosmos by weight. Dark matter, of which we know nothing except that its collective gravity sculpts and holds the galaxies together, amounts to 25 percent.

The remaining 70 percent is dark energy, pushing everything apart; we don’t know anything about that, either. We only know that this “dark sector” exists because of the effect of its gravity on the luminous universe, the motions of stars and galaxies.

A theory that leaves 95 percent of the universe unidentified is hardly a sign that science is over.
Wait -- there is a prediction for the density of dark energy, but we don't know anything about it? So how was the prediction made?

We actually know a lot about dark matter and dark energy, and it is possible that we now know essentially all that we will ever know.

Dark matter has gravity, but does not interact with electricity or light. Its gravitational effects are well understood. What else is there to understand?

Dark energy could be the zero point energy of the vacuum. All quantum systems have such a zero point energy. We can't derive it from first principles, or from the geometry of a Calabi-Yau space, but quantum theory suggests that we should expect it. It appears to be homogeneous, isotropic, and Lorentz invariant. It is just the energy of the vacuum. There may be no more to explain.
Maybe we don’t understand gravity after all, some astronomers say. “I worry that we deify Einstein too much,” Stacy McGaugh, an astronomer at Case Western Reserve University, told Gizmodo in June.
We definitely deify Einstein too much.
If scientists want any gift for the holidays, it’s some new physics that would break the stalemate of these “standard models” and provide new clues to our existence.
This is like a medical researcher hoping to discover some new disease, or the CIA hoping to discover some new terrorist network, or a computer scientist hoping to find flaws that destroy our information infrastructure.

If the disease is already out there killing people, then sure you want to figure out how to diagnose and treat it. But why would you hope for the disease?

Physicists have figured out the four fundamental forces. The big problems have been solved. That is a good thing, not a bad thing. Am I supposed to hope that the laws of physics are wrong just because some bored physicists don't have anything to do? That seems to be what Overbye and everyone else are saying.

1 comment:

  1. Can you imagine how boring things would be if we had a theory which explains everything?