The existence of antimatter | Lee Smolin, Sabine Hossenfelder and Tara Shears

Lee Smolin, Sabine Hossenfelder and Tara Shears debate the existence of dark matter.

From Star Trek to Dan Brown novels, Doctor Who to Marvel Comics, antimatter has fascinated since it was proposed by Dirac in the 1920s and confirmed with the discovery of the positron a few years later. Heisenberg - the father of modern physics - referred to its discovery as "the biggest jumps of all the big jumps in physics". But there's a fundamental problem. The theory predicts the disappearance of the universe within moments of its inception as matter and antimatter destroy each other in a huge cataclysm. Yet 14 billion years later our universe exists, and scientists still uphold the antimatter theory.

Is it time to give up the idea that for every particle there is an anti-particle or would this be a threat to quantum mechanics itself? Is it right to overlook fundamental flaws in a theory in favour of neatness and buzzwords? Or nearly a century on from its inception, should we stand by the theory confident that a solution will be found?

Founding member at Perimeter Institute for Theoretical Physics, Lee Smolin, professor of Physics at Liverpool University, Tara Shears and leader of the Superfluid Dark Matter group at the Frankfurt Institute, Sabine Hossenfelder battle over the very fabric of the universe. Hosted by Hilary Lawson.

#SabineHossenfelder #LeeSmolin #TaraShears

Sabine Hossenfelder is a theoretical physicist who researches quantum gravity. She is a Research Fellow at the Frankfurt Institute for Advanced Studies where she leads the Superfluid Dark Matter group.

Lee Smolin is a theoretical physicist, a faculty member at the Perimeter Institute for Theoretical Physics, an adjunct professor of physics at the University of Waterloo and a member of the graduate faculty of the philosophy department at the University of Toronto.

Tara Shears is a particle physicist and the first female physics professor at Liverpool. Shears is “rapidly becoming the go-to scientist to explain all things CERN” (WIRED).

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What do you think of this debate? Leave a comment below.

[erikfinnegan]

Feels like the host was overwhelmed by the topic and his guests. One example: when Sabine said we don't need larger colliders he appeared to imply she didn't want to experimentally verify at all; but, I believe, we know from her public statements that she believes we need other types of experiments.

In general, the host appeared to want to stir a fight, but none of his guests took it.

[owencampbell]

I like Sabine's way of thinking, it's an honest way to see, understand, and solve problems, not fitting answers to solve an acceptable theory or explanation.

[xjuhox]

After the Dirac's idea of positron, it was *de Broglie* who first suggested that every particle has its antiparticle. De Broglie was a master of throwing crazy ideas around ^^

[AngusRockford]

I think Lee and Sabine made clear at the outset that there was no real problem with our current understanding of anti-matter, and the moderator went round in circles just begging the question for at least half an hour. The moderator seemed, at worst ill-equipped, at best unprepared for this discussion. He demonstrated repeatedly that he wasn’t really listening to his guests, or was disregarding their answers to keep chasing a faulty premise. It had been better if he had just abandoned the premise that there was something wrong with the current model and gone a little deeper into the philosophical discussion about whether things like “beauty” or “simplicity” were necessary to scientific theory, or deeper into alternative theories for the matter/anti-matter disparity, like Lee’s Cosmological Natural Selection, but he seemed determined to breeze past all that.

[dhawkins]

The host seemed to miss Sabine's point about initial conditions. All physical theories start from assumptions and all physical theories require externally specified initial conditions in order to make predictions. Those assumptions and initial conditions are justified empirically by testing the predictions of the theory. That is, the proof is in the pudding. There is no deeper justification, and *cannot be*. It may be possible to find a deeper, different theory that reduces the number of assumptions and reduces the amount of externally specified initial conditions, but not all the way to zero. You can't get something from nothing. It's amazing how many people haven't really internalized that.

[Sletty]

Having an host competent in the matters he should supposedly know for conducting a debate is usually a good idea.

[pihi]

It's like trying to learn rules of Snooker by observing some middle-game. You discover how balls move, how collisions work, the rules of counting reds and colors etc. But then you try to trace back and find out the initial ball positions. Perhaps with very advanced analysis you manage to do that. Then someone asks you Why? Why are the red balls all in one pack and colors on the spots? There is no way to answer that. There is a specific rule to set up the board; without observing the game from the start you will never be sure of the initial setup, much less why. You can come up with wild metaphysical speculations, even perhaps seeking minima (which initial setup makes for the most interesting, most difficult, fastest, ... game). But you can't know "why" unless you can observe the whole context of players, judges, rules, history etc. which is a completely different level than observing the actual balls and table and shots.

[charc]

More people should know of Lee Smolin. A brilliant mind. Philosophically and scientifically mature.

[chrihipp]

Following Sabine's arguments requires only basic logical reasoning. She explained that this topic is not an interesting topic and this cannot be solved with the current theories. Since there are real problems in physics, one could even call this a waste of time and resources.

[urfinjuice]

This is just comical. The host is so confused. He has obviously no idea what he is talking about. And then the noise of his fists bumping on his desk. I feel a bit sorry for him. Someone should have helped him not to make a fool of himself.

[sipanica]

This video is an example of how to waste the time off three brilliant minds. Very unprepared moderator. Science is not drama or politics.

[PsiSubDiego]

I feel so sorry for the host. Smolin, Sabine, and Shears tried to be as charitative as they could, and deviate the discussion to more interesting subjects, but he was just so appallingly ignorant about the subject. Poor dude.

[joyecolbeck]

Thankyou. This was a pleasure to listen to.

[fractalnomics]

29:50 Sabine, the 'strong force'.

[gustavderkits]

Lee Smolin’s explanation is so good. His citation of C. S. Pierce is fine. Pierce used the neologism “abduction” to describe reasoning to a best explanation.

[JimGobetz]

Ok that was great, always love Sabine and Lee and was nice to hear Tara as well. I'd like to see a new Solvay type conference, maybe funded by Jim Simons, bring folks like these and other luminaries to wrestle out the next great advance.

[arekkrolak]

Sabine is the best, she will destroy mercilessly every bs the click baiting journalist will say to attract attention :)

[DrLogical]

Poor physicists. They tried to do their best with the host's deeply held confusion

[Jean-Pierre-PETIT]

After watching this video one must formulate a conclusion. A century after the beginning of the construction of the cosmological model theorists have no theory to propose to justify the absence of observations of primordial antimatter.

Lee Smolin has very briefly mentioned the name of Andrei Sakharov who had assumed the existence of two entities to which he gave the name of twin universes.

In these two worlds he imagined that the initial situation corresponded to a plasma of quarks and anti-quarks, in the free state, mixed with gluons.

The two universes evolving, one would have then in both universes creation of matter and antimatter from quarks and anti-quarks. The key hypothesis of Sakharov consisted in imagining that the rate of production of quarks, in our fold of universe would be slightly faster than the rate of production of anti-quarks. Thus after the annihilation of the matter-antimatter pairs we would find, besides photons, a remnant of antiquarks. The situation is symmetrical in this other fold of the universe where photons, antimatter and a remnant of quarks would exist.

This represents a form of answer to the question "where is this primordial antimatter? "The answer given by Sakharov in 1967 was "it is in another universe, connected to ours by this "singularity" that is the "Big Bang.

But he added that the arrows of time were then antiparallel, an idea that Niel Turok and other authors are beginning to take up, who envisage the existence of this second fold of the universe, CPT symmetrical to ours. The the Big Bang has a new name. It becomes the "Janus point".

At this stage we can consider two things. The first is to fold the universe according to the two-folds cover of a P4 projective space. The image that we can give consists in saying that until now we had considered a 4 dimensional hypersurface with only one family of geodesics, and that this new model is equivalent to endow this hypersurface with a front and a back, each one having its own geodesics resulting from its own metric.

We thus have a "bimetric" model. The combined points of these two folds are thus joined and can interact. The problem is how?

Here we can think about the meaning to give to this T-symmetry. The quantum theory of fields also contains operators T, of time inversion and P, of space. These can be arbitrarily chosen:

-Linear and unitary

- Antilinear and antiunitary.

This theory chooses, arbitrarily, that P is unitary and T anti-unitary, to avoid the appearance of negative energy states, considered a priori as non-physical.

A relatively recent discovery was the acceleration of the cosmic expansion, due to a negative dark energy. So we are led to re-examine these solutions with negative energy and mass, simply by choosing a linear and unitary T operator.

This is what the Belgian mathematician Nathalie Debergh did in 2018 by showing that the Dirac equation would then generate such states. The paper, issued in the the Journal of Physics communication :

N.Debergh, J.P.Petit and G.D’Agostini : Evidence of negative energies and masses in the Dirac equation through a unitary time-reversal operator., J. Phys. Comm. 2. (2018) 115012

If we consider that we are in the presence of two populations of masses and energy of opposite signs, then it is normal that we cannot observe the negative mass particles, because they emit photons of negative energy that our optical instruments cannot capture.

A recent article :

J.P.Petit, G.D’Agostini and N.Debergh : Bimetric models. When negative mass replaces both dark matter and dark energy. Excellent agreement with observational data. Solving the problem of the primeval antimatter.

summarizes several previous publications in peer reviewed journals (Nuovo Cimento, Astrophysics and Space Science, Modern Physics Letters A) presents the corresponding mathematical and geometrical background, constructed in such a way as to preserve the equivalence principle in both populations. Then the interaction laws are :

- Masses of the same sign attract each other according to Newton

- Masses of opposite signs repel each other according to "anti-Newton".

The model then accounts for many observational aspects. The energy of negative masses being itself negative, we have here this "dark energy", responsible for the acceleration of the cosmic expansion.

The negative mass pushing back the positive mass, it is this energy that ensures the confinement of galaxies.

We obtain an interesting structure where we find for example a regular distribution of negative mass clusters, which dictate the large-scale structure of the universe, the positive mass, lacunar, being in the interstitial portion of space. The Great Repeller, discovered in 2017, is then one of these objects.

This also answers the question that was asked in this interview. Primordial antimatter exists, and it has negative mass. It consists of anti-hydrogen and anti-helium. The corollary is that the search for positive mass dark matter is doomed to failure.

A video presenting the Janus Cosmological Model model can be found. Search « Janus 29 »

Sabine Hossenfelder, tried in 2008 (Physical Review D ) to produce a first bimetric model, but without success, knows this article, where her own work is abundantly quoted and debated.

J.P.Petit, astrohysicist