## Tuesday, March 19, 2013

### Michio Kaku's confusing Higgs remarks

I partly but not quite agree with Sean Carroll's and Matt Strassler's criticisms of this CBS interview (HTML) with Michio Kaku, a co-father of string field theory and a sometimes excessively lively popularizer of physics, not to mention more general aspects of science fiction marketed as science:

Sorry if CBS inserts half a minute of ads.

It seems that Michio Kaku who watches The Big Bang Theory on the same TV station – together with 20 million Americans in average – couldn't resist to incorporate the Big Bang to his new story about the Higgs boson. And the result of his creative artistic work sounded strange to physics ears.

However, see also Phil Gibbs' take on this which is closer to mine.

The fuse behind the interview was the CERN announcement a few days ago that the 126 GeV Higgs-like particle really behaves like the Standard Model Higgs boson. The agreement is striking but I think that this "event" has been heavily overhyped.

We've been learning that the new particle is extremely similar to the Standard Model Higgs boson for more than a year and we have had very strong prior reasons to think it's the case, anyway. Moreover, the evidence that the particle behaves in the Standard-Model-prescribed ways was growing gradually and there wasn't any real eruption a few days ago.

Michio Kaku says that the event was huge and champagne was flowing in physics departments throughout the world. I am not sure. What I am sure about is that this was the legitimate description of the excitement on July 4th, 2012. Champagne was surely flowing across the halls of the Institute for Advanced Studies in Princeton, New Jersey. If you care about the microscopic details, Nima Arkani-Hamed paid for the beverage and Robbert Dijkgraaf, the director, was the waiter. Yes, it seems like Ed Witten, Juan Maldacena, and others had to be satisfied with the role of rank-and-file drunkards.

So aside from the confusing timing, Kaku's colorful description of the excitement sort of conveys a true story. And yes, Michio Kaku may be expected to make similar stories sound a little bit more spicy.

Also, CBS used the term "God particle" and Michio Kaku actually mentioned that the phrase usually makes physicists cringe. Well, as you know, I have no real problem with this phrase and I even think that it's arguably more polite and fair when it comes to the credit that should be given to several fathers of the "Higgs" mechanism.

But the most controversial point of the interview is the claim that the Higgs discovery helps us to understand how the Universe began. Michio Kaku even says that the Higgs boson is what gave the bang to the Big Bang and that it is the missing piece of the Big Bang theory, and so on. These highly unusual comments are combined with the usual remarks that the Higgs field gives masses to all other particle species.

Well, a physicist will have a trouble to understand why exactly the Higgs boson should be responsible for the ignition of the Big Bang. The Higgs condensate was born and it was immediately important a trillionth of a second after the Big Bang when the electroweak phase transition took place. But all other fields were very important when the Universe was dense and hot, too. There have probably been many other phase transitions right after the Big Bang, too. So why is the Higgs field getting these exclusive rights to boast the authorship of the Big Bang?

As several later sentences by Kaku reveal, Kaku justifies his idiosyncratic hype by the Higgs boson's being a relative of the inflaton. And yes, the inflaton is what probably gave the bang to the Big Bang. In fact, five years ago, I discussed some problematic yet intriguing models in which the Higgs boson actually is the inflaton (a paper with 250+ cits). For these models to work, there has to be an uncommon interaction term in the Lagrangian, the squared Higgs multiplied by the Ricci scalar:$\LL_{\rm tot} = \LL_{\rm SM} -\frac{M^2}{2} R - \xi H^\dagger H R$ The usual minimal theory has $$\xi=0$$ but for $$\xi$$ of order tens of thousands, you start to get a behavior in which the Higgs field may behave as the inflaton, too. Well, these models are problematic (the Lagrangian above mixes a nicely renormalizable Standard Model with the non-renormalizable gravity treated as a field theory and various extra problems result from that) and they have surely not been demonstrated at the LHC. On the other hand, I don't think that the LHC has brought us the relevant data that would exclude these couplings to the spacetime curvature, either. Am I wrong? I realize that the LHC has surely excluded many other, more conventional yet non-standard non-gravitational couplings of the Higgs field.

But even if we ignore these unpopular models, I must sympathize with Michio Kaku's general point that the Higgs boson is the first fundamental scalar we have discovered in Nature and it belongs to the same family as the (still hypothetical) inflaton. And the scalar fields are those that may get vevs so they're naturally more important than the spinning particles for various phase transitions and other changes that have been shaping the character of the Cosmos around us.

In particular, fundamental scalar fields are mundane in string theory and because assorted non-string theorists have proposed various memes and would-be reasons why fundamental scalar fields shouldn't exist in Nature at all (think about the philosophy beyond preon theories of numerous kinds), the discovery of the Higgs boson is a positive point for string theory even though, of course, string theory is not needed to explain the existence and the behavior of the Higgs boson. However, in a non-stringy setup, one is offered various reasons why such fields could be forbidden in general while string theory has always unequivocally stated that scalar fields should exist.

So I don't think that there exists a justification to say that the Higgs boson (or field) found at the LHC is the key particle (or field) that launched the Big Bang.

On the other hand, I do think that the Higgs field (and its quanta) did play a somewhat elevated role right after the Big Bang, especially during the electroweak phase transition. The cosmological spin of the Higgs boson discovery is certainly an unusual rhetorical exercise but I would personally not trash Michio Kaku just for saying something that is unusual – because within the error margins that are unavoidable in similar shows and proclamations addressed to the laymen, his story isn't qualitatively less true than the other things that are often being said about the Higgs boson (and other things) in the popular media.

In fact, I can even turn Kaku's claim that "the Higgs boson is the last missing piece of the Big Bang theory" to a valid claim by making just one modest modification. Replace the "Big Bang theory" by "the standard model of cosmology" which is pretty much a refined synonym. The standard model of cosmology contains the usual solutions to Einstein's equations of general relativity but, in a less central way, it also incorporates the Standard Model of particle physics. The latter is needed to understand many events right after the Big Bang. Because the Higgs boson was the last missing particle of the Standard Model of particle physics, you may perhaps also say that it was the last missing piece of the standard model of cosmology – and therefore the Big Bang theory, too.

Well, I needed a long explanation to partially justify Kaku's words but the same is true for many other popular "licenses" that are constantly repeated by the popularizers of science. The only difference is that everyone knows the "partial justification" of the usual stories but because Kaku was the first major pundit who have spun the Higgs boson discovery in this cosmological way, almost no one understands the justification for his oversimplified story. I tried to give you one. Be sure that Kaku's cosmological interpretation of the Higgs is much more justifiable by physics than Carroll's cosmological interpretation of the origin of the arrow of time!

So I would give Michio Kaku C– for accuracy but A– for originality. ;-)

1. I'm a big fan of Michio Kaku (after you of course ;-) and I am glad you forgive him for some inaccuracy. Excitement is a driver for the layman ;-) I guess he shouldn't be talking about an explosion when the Big Bang occurred but rather a sudden expansion, right ?

2. Well, excitement is a cool thing but a dangerous weapon, too. ;-)

What's wrong with an explosion here? Well, one usually says that the Big Bang was no explosion because explosions tend to have one preferred center, the ground zero, but the expansion of the Universe occurs everywhere. That's good but by all local observations, it still looked like an explosion! ;-)

3. I waited for such a nice clarifying article to appear here since Matt Strassler got driven up the wall by Kaku's cosmological remark ... :-)

4. noone from czech tv was smart enough to propose you a show yet? even if you don't like, it pays.

5. Dear Dilaton, I can't resist to mention that the newest paper co-authored by the same physicists, Shaposhnikov and Bezrukov, is about the... Higgs-dilaton cosmology. ;-)

http://arxiv.org/abs/arXiv:1212.4148

You together with Peter Higgs may do all the work expected from Alan Guth and others. :-)

6. They actually have - after I starred in a different TV show about the Husak Children generation's folks who started to affect world right after the Velvet Revolution.

It was supposed to be for kids or teenagers etc. and they were excited. But I didn't say a clear Yes so the offer faded away.

I and Peter Higgs did an excellent job, didnt we :-D?

Now everybody (in particular sourballs and trolls) should rather be careful and think thrice before making me upset and taking the risk that I explode out of anger and a new vigorous inflationary phase starts :-P :-D ;-)

http://i1223.photobucket.com/albums/dd502/nurekowser01/3-Big%20Bang/3-2-inflation-1.jpg

Cheers

8. If you are at the center of a detonated junk of TNT, and the TNT covers everything within the Hubble horizon, isn't it exactly like explosion?

9. This paper uses unimodular gravity which is one of those models where the vacuum energy does not gravitate. I had a question for you Lubos. Does string theory always predict GR as the low energy effective theory of gravitation or are there exceptions?

10. Interesting interview, I would have missed it.

I had no trouble following /understanding his speculations. As an experimental physicist I can leap over mathematical arguments :). That is, when he brought in the inflaton I was satisfied of the connection to the bang. I am sure that laymen got some info useful as a background knowledge.

Physicist nit pickers of statements in a popularized interview must be theorists with their own pet physics view and cannot be playful with physics.

11. Hubble horizon is of course "Hubble horizon". Fixed by speed of sound not speed of light.

12. Kashyap VasavadaMar 21, 2013, 1:53:00 AM

Hi! As you know, the other blogs have intense discussions on the
following questions in addition to criticism of Kaku's overzealous hype!
(1) Hadron masses do not come from Higgs but from kinetic energy of q,
qbar and gluons with very small contribution from quark masses. (2)
When was the Higgs field switched on? Could there be other Higgs related
to inflation? Is this correspondence totally ruled out? (you probably
answered this question in above, but more discussion will be usefuI) I
would like to know from a string theory expert such as you, what does
string theory say about these questions. In particular how are strings
related to hadrons,leptons and bosons such as higgs, photons and Ws as
far as energy and structure are concerned? Is it too early for strings
to answer these questions or the answers are same as conventional field
blog only recently. So if you have discussed these things in past,

13. Kashyap VasavadaMar 21, 2013, 2:23:00 AM

Hi! As you know, the other blogs have intense discussions on
the following questions in addition to criticism of Kaku's overzealous hype!
(1) Hadron masses do not come from Higgs but from kinetic energy of q, qbar and
gluons with very small contribution from quark masses. (2) When was the Higgs
field switched on? Could there be other Higgs related to inflation? Is this
correspondence totally ruled out? (you probably answered this question in
above, but more discussion will be usefuI) I would like to know from a string
theory expert such as you, what does string theory say about these questions.
In particular how are strings related to hadrons,leptons and bosons such as
higgs, photons and Ws as far as energy and structure are concerned? Is it too
early for strings to answer these questions or the answers are same as