## Sunday, September 14, 2014 ... //

### Higgs the mass killer: in defense of Stephen Hawking

Stephen Hawking was brought to deep financial troubles when he lost $100 against TRF guest blogger Gordon Kane after the two men have agreed on a bet that the Higgs boson would or wouldn't ever be discovered, or something like that. (I have won$500 for an analogous bet: yes, the Higgs boson has been discovered.) So evil tongues could argue that it's the reason why Hawking says that Higgs has made physics less interesting – and now why he accuses the Higgs particle of the plan to destroy the world.

Will it destroy the world?

Probably not but the threat, while small, has a totally legitimate scientific justification.

Yahoo News were among the tons of sources that have offered the disturbing prophesy by the famous physicist. Matt Strassler and especially Don Lincoln (full) wrote nice texts that try to calm the public and present Hawking's warnings as scientifically misleading.

I wouldn't be equally critical.

Now, Strassler and Lincoln are right about all or pretty much all technical issues. So it is not a single Higgs boson that would create the doom but the Higgs field. (Although, particular processes may catalyze the decay-of-the-vacuum instantons, so I wouldn't say that the rate of the doom is completely independent of the particles that are produced within the Universe.)

The recently measured mass of the Higgs boson near $$125\GeV$$ is above the masses for which the Standard Model would predict a full-fledged instability. But this value of the mass is below the masses for which the Higgs field remains completely stable even at Planckian temperatures. It is somewhere in between – the Standard Model Higgs field is "metastable".

This picture of Don Lincoln seems nice enough to explain the difference between "stability", "metastability", and "instability". A stable configuration doesn't have a way to seriously lower the energy relatively to what seems as the "ground state" we start with. The ground state corresponds to the "global minimum" of the energy. An unstable configuration allows such a lowering – it's enough to change some "coordinate" $$x$$ by an infinitesimal amount. Because there is a contribution to the potential energy going like $$-x^2$$, the point $$x=0$$ is stationary (the derivative i.e. the force is zero over there) but $$x=\varepsilon$$ is preferred because the stationary point is a maximum, not a minimum, with respect to variations in that direction. A small perturbation will drive $$x$$ to $$x=\varepsilon$$ where the force is no longer zero and in fact drives $$x$$ to exponentially grow in time (the exponential growth or a sinh/cosh is the opposite-sign counterpart of the oscillating sines we know from the harmonic oscillator whose potential energy goes like $$+x^2$$).

A metastable configuration, and that's what the Higgs field would occupy if the Higgs mass were $$125\GeV$$ (it almost certainly is) and if the Standard Model were the whole story (it probably isn't), is one where the energy of the "ground state" we want to occupy is at a "local minimum". Small variations of the angle of the stool raise the energy so the stool doesn't want to fall. However, if you help the stool to overcome a barrier, it will be able to "repay" the invested energy including some interests. When the stool falls completely, it will have a lower energy, after all.

The metastable Higgs field is analogous. Small changes of the Higgs field seem to increase the energy so they are disfavored. But if the Higgs field were able to change by a significant amount, it would find out that there is a "better" (lower-energy) place for the Higgs field to live. However, this place kills everything in the Universe because the effective laws of physics would be completely different over there.

Classically, the metastable points (local minima of energy) behave just like the global ones. The stool will stand forever. Quantum mechanically, we must always deal with the tunneling effect. The stool is able to spontaneously fall because it has a nonzero probability to overcome the energy barrier that is classically impenetrable.

If the Standard Model were the whole story, we might calculate the exponential that determines the small probability of the Higgs tunneling, and it would imply that the lifetime of the Universe would be at least equal to a trillion of years, and possibly larger. The Sun will go red giant in 7.5 billion years so the "Higgs decay of the Universe" is 100+ times less urgent according to the Standard Model.

But there may be extra physics which either cures similar instabilities – and even metastabilities that are replaced by stable configurations; supersymmetry is the most motivated theory that achieves so. However, new physics may also make things worse. There may be new scalar (Higgs-like) fields that imply a metastable threat, perhaps a much more urgent one than the Standard Model trillion-year threat.

I think that this is a cool piece of physics that was pioneered primarily by Sidney Coleman, an ultimate physicists' physicist, and even from the viewpoint of the media, these results are sort of fascinating and heavily underreported. Physical theories in which the Universe gets destroyed entirely are completely allowed. At a random place and random time (with a calculable probability per unit volume and unit time), a "seed of doom" may be born ("nucleated") and it may expand pretty much by the speed of light and destroy everything it hits.

The tiny probability of such a nucleation determines the lifetime of the original Universe, if it is finite at all. The lifetime is pretty much an exponential and the exponent is a huge number. That's why lifetimes as long as $$10^{100}$$ years and even $$\exp(10^{100})$$ years may occur in calculations. Due to the possibility to get such high numbers and thanks to the fact that low numbers are not really allowed because the Universe is still around, we may say that the lifetimes comparable to 10 billion years seem rather unlikely.

But they can't really be excluded.

There may be a metastable scalar field in the Universe that destroys the Universe roughly after 10 billion years.

If the typical lifetime were much shorter than 10 billion years, the probability that we would still be here would be dropping exponentially (the exponent is –13.8 billion years over the predicted lifetime, roughly speaking), and this quickly decreasing tiny exponential would also encode the probability that such a hypothesis is right. The existence of an instability with a lifetime shorter than 1 billion years is surely excluded at more than 5 sigma level.

On the other hand, if we imagine that there is a metastable field that implies a decay of the Universe with the lifetime between 10 and 20 billion years, for example, which is reasonably compatible with the fact that we haven't died yet, then it is an important threat, indeed.

Over the next 7.5 billion years, we will see approximately one extermination of life on Earth due to the Sun that runs out of fuel and becomes the red giant. The metastable field from the previous paragraph would add one more threat – one extinction per 10 billion years – that is equally fast, likely, or urgent. And it is unpredictable. So while the trouble with the Sun's fuel is extremely unlikely to kill us in the next 1 billion years, the "decay of the Universe" would have a significant risk of 10 percent to kill us already in the next 1 billion years. The death is random and the probability of the universal death is proportional to the time.

Let me calm you down: if the Universe is ever destroyed in this way, you won't feel anything because the "doom" or "nothingness" spreads almost exactly by the speed of light and faster than any signals in your nerves.

Is there a metastable field in Nature that would imply an instability giving the Universe the lifetime of just tens of billions of years? Probably not. The theories with such an instability are slightly tuned. But the probability could be 1% according to what we know. I think that even with this probability, it's fair to say that a metastable scalar field is still much more likely to "completely eradicate the life on Earth" than a CO2-induced climate change, for example. The former is reasonably possible – the probabilities are given by a power law with a reasonable probability. The latter is not possible – the probability that a clearly minor effect of CO2 destroys everything is a tunneling-effect-styled unlikely event whose probability is exponentially small (and therefore parametrically smaller).

So to a large extent, I believe that it is right for Stephen Hawking to popularize the "decay of the false vacuum" because it is a set of insights and methods in theoretical physics that are analogous to the cosmic inflation, for example, but they speak about the future, not the past, and they speak with a more anxious voice!

The previous article about the decay of the Universe was the June 2014 blog post combining the BICEP2 and Higgs results to a potential threat. Previously, I have discussed the Higgs instability many times on this blog, e.g. in

Why a $$125\GeV$$ Higgs boson isn't quite compatible with the Standard Model

Higgs: living near the cliff of instability

Implications of a $$125\GeV$$ Higgs for SUSY

Why the Standard Model isn't the whole story
Don't be "really afraid" because the risks are tiny but be sure that such a cosmic catastrophe does follow from various totally sensible, professional theories of the cutting-edge physics (and they're even fully incorporated on models arising from string theory) and the predicted rates may be extremely long as well as relatively short so Hawking is surely not making everything up.

#### snail feedback (23) :

reader NikFromNYC said...

You are being silly repetitive. No, there is *no* record of sudden planetary CO₂ surges, up from a steady baseline, so you are living on some other planet. You WILLFULLY ignore, not even just discount, but ignore ocean temperature entrainment of CO₂ atmospheric concentration. You are a royal
albeit sophisticated sophist, giving away the fact that you of all people are among those most aware of the scam nature of Global Warming alarm, since you pointedly refuse to comment on the new ghost blade hockey stick. Oh, but I'm the bad guy somehow. Do you have a masochistic fetish, Mr. Wrong with the girl avatar? It's getting old bitch slapping you into real debate silence, without even seeing you ever once smile.

reader anna v said...

Well, I am sure that CO2 must be hiding somewhere there, and if not, on the precautionary principle a tax should be imposed proportional to the mass of each person for research on how to avoid falling off the false vacuum.

reader Luboš Motl said...

Nik, removing a user from pre-moderation is no formality. I did it for one of your accounts but a review suggests that 90% of your comments are obnoxious so I will probably remove that account from the white list as soon as I encouter another comment from that account.

You will never write a comment suggesting that you have a right to be a on a whitelist again and you will reduce your attacks on other users at least 3 times, otherwise I will move you to the black list instead.

reader martin said...

Anti quantum mechanics cranks are making their shameless propaganda against quantum mechanics louder .

http://www.reddit.com/r/science/comments/2gc4nz/the_quantum_world_becomes_less_weird_the_last/

reader Luboš Motl said...

LOL, exactly, I just saw about 30 articles on that "breakthrough". Too exhausted to respond.

reader Luboš Motl said...

It's a great question. In our Universe which is already almost like de Sitter space and will be increasingly so, the bubble of the new vacuum indeed expands by the local speed of light only - the world lines of the walls are "null" or light-like.

This speed is really not enough to catch up with the quickly receding places behind the cosmic horizon, and they will be forever safe from this particular bubble of the new vacuum. They may be hit by another bubble later, however.

The causal diagram of de Sitter looks like this

https://higgs.ph.ed.ac.uk/sites/default/files/penrose-deSitter.jpg

and the expanding bubble is like a V-shaped triangle attached to the upper edge, with angles 45 degrees.

http://www.kensholabs.com/physics/susskind/CosmologyBH/CosmologyBH_C9_files/image050.png

reader Uncle Al said...

Supernovas, hypernovas, magnetars, stellar and galactic black holes, fat girls, single cosmic ray protons with the energy of a hard-thrown baseball, and the LHC if it ever works properly leave reality intact. No strangelets kicking matter to a lower rung. I'm not sweating this one re Pascal's wager.

Trinity test site had a bet going as to whether the first piddling 15 kt gadget would ignite the atmosphere. The 50,000 kt Tsar Bomba didn't do it either, nor Jupiter being repeatedly initiated by comet Shoemaker-Levy.

http://news.discovery.com/space/could-rhic-strangelets-spawn-doomsday-140213.htm

People will enthusiastically believe anything except reality. Exploit that.

reader Hacienda said...

Among the many ways to die, death at the speed of light would actually be the most preferred.
And universe death is about as close to true death a human can achieve.

reader Gordon said...

Yes, Sidney Coleman seemed to be another Feynmanesque physicist--smart-as-hell, funny, full of interesting ideas, and a great lecturer. His papers on vacuum instablility started the
"universe is doomed" speculations, and I bet he had fun with it.

http://www.sns.ias.edu/pitp2/2011files/PhysRevD.21.3305.pdf

Then, of course, I can always refer to the ultimate unimpeachable canonical reference:

http://motls.blogspot.ca/2011/10/bubble-of-nothing-and-other.html

Finally, a Sidney lecture brought to my attention by Lubos that made me want to learn a smidgen of QM, a lacuna in my math/physics ed, "Quantum Mechanics in Your Face":

http://media.physics.harvard.edu/video/?id=SidneyColeman_QMIYF

BTW--Those in the AGW alarmist camp, who champion the Precautionary Principle of Bankrupting Economies and Amassing Personal Fortunes, should now focus on preventing the sun from becoming a red giant.
Gore could begin production on "An Inconvenient Truth--Redux" with scary pics of solar prominences and magnetic storms...a whole new source of income and directorships in solar power companies for him now that he sold his network to Al Jazeera.

reader Gordon said...

Hmmm, it seems that Stephen Hawking should avoid casinos and games of chance---his betting record is horrendous...he must be on bookies' sucker lists ;)

reader Antonio (AKA "Un físico") said...

Hi Lubos, I like your thought: "it's fair to say that a metastable scalar field is still much more likely to "completely eradicate the life on Earth" than a CO2-induced climate change".
The metastability of scalar fields was important, e.g., for the Higgs field when it passed through a phase transition at T=10^15 K, but nowadays at T=3K even if anyone wanted to include (by hep-th/1004.2015) the effects of any other scalar field (i.e., the interaction with inflatons, meaning, with the expanding universe): that metastability is not important. Universe at present will not nucleate. (By the way Lubos, which theory gives you that 10^100 or its exponential lifetimes?).
I have an opinion about Hawking: he wants more to appear in the media than to divulgate science. It is a pitty for physics and a shame for organizations like Starmus (which I'd better call Starm(in)us :) ).

reader Gary Wilbourn said...

Due to locality, we are safe from the worst of probabilistic phenomenon. Any universe destruction occurring , if it is occurring, beyond our cosmic horizon, cannot catch up to us because H=c at the cosmic horizon. So we need only to calculate the probability of these destructive phenomena occurring within the volume of space encompassed by our cosmic horizon.
As for black hole interior phenomenon, what are the entropic implications of the formations of these events? Clearly cosmic sensorship must apply in this case as in all other cases involving black hole interiors.

reader Peter Golian said...

According to my prediction and preliminary calculations Higgs field
is 10000 times faster that speed of light, that causes due to
relativity time “shifts” about eight hours. Don't be afraid there
is faster field than Higgs field as 10E24 faster than speed of light
and time “shifts” are doing if there is examining Higgs or not,
it is nature.

reader thejollygreenman said...

So can we expect the clamouring for a global carbon tax to be replaced by a Higgs tax? I am only interested in things that will effect my pocket, the rest means nothing to me in my finite lifetime.

reader CB said...

I like to encourage Climate Deniers to air their mentally deranged ideas in public. I think it's therapeutic for them.

...it's your blog though.

For what it's worth, Nik's comments are tame in comparison to some others I've encountered.

reader CB said...

Luboš may do whatever he wants with this blog. It's his blog.

It seems to me both you and Luboš are mentally ill Climate Deniers, but I'll let him speak for himself and you speak for yourself...

I am repeating my question about Earth's history... because you haven't answered it. Have you any idea how many Climate Deniers behave in such a cowardly fashion? If Climate Denialism weren't a mental disorder, why should this be?

If it's so likely that polar ice caps will be able to withstand CO₂ so high, why isn't there a single previous example of them doing so in Earth's history?

reader CB said...

"you ignored my Data 101 reality check post, CB, did you not?"

Did you post anything about the unsuitability of GEOCARB III to gauge CO₂ during the late-Ordovician glaciation or the more detailed measurements that suggest a crash in CO₂ to almost zero caused this glaciation?

www.geology.ohio-state.edu/~saltzman/youngetal_2010.pdf

If you didn't, why should anyone bother paying attention to you?

reader Luboš Motl said...

Dear CB, I've approved all of your posts so far but you have depleted the centennial limit on expletives such as "mentally ill climate deniers" so you were placed on the black list. I hope that you have enjoyed the visits.

reader Quantum said...

Even if the metastability lifetime is doubly exponential, does that mean we can't live forever? Or at least, can our memories survive forever with some other entity to relive them in the future? Will we be totally forgotten by the end of time?

Of course, if the lifetime is doubly exponential, heat death due to the accelerating de Sitter expansion of the universe due to the positive cosmological constant would happen first, wouldn't it? But that's still death.

How can we become immortal? Or at least have immortal memories? Or will we lose consciousness and return to nothing?

Maybe the laws of physics are supersymmetric and there is a landscape of stable and metastable phases, and there exists a supersymmetric phase with an exactly zero vacuum energy aka cosmological constant. Can our descendants engineer a phase transition to that supersymmetric phase and transmit our memories across coherently to the new phase? Then, they can construct sentient entities which can live forever by hibernating a la Dyson, and those entities can relive our memories forever and ever without end.

reader youeitherdontknoworyoudontknow said...

So you're luring new readers by saying in the opening part that higgs was discovered? Because you admit in the post that it wasn't, as we all know. Google profits must be down when your audience shrinks that fast. Still driving that 1978 Moskvitch?

reader Luboš Motl said...

Cheap crank, this was your last comment on this blog.

The Higgs boson was discovered on the Independence Day of 2012, I got my \$500 from the bet that it would be discovered on the same day.

Those of us who were sensible and followed the experiments knew with 99.9% certainty that the Higgs boson existed and had mass close to 125 GeV since December 2011, and theoretically speaking, competent particle physicists have known that the Higgs boson had to exist approximately from 1964.

reader br said...

OK, and with a couple more clicks I found the temperature profiles on the same site. Then I found http://www.climate.gov/news-features/understanding-climate/2012-state-climate-global-sea-level which was interesting - not only is ocean heat increasing, but meltwater contributes a x2 greater sea level rise (I initially misread the NOAA site thinking it was all heating). The second figure on the climate.gov page implies glaciers and land ice continue to melt, and have shown no hiatus since 2000. So clearly there is some sort of warming still going on, despite the hiatus in mean surface temperature. That was how I was finishing my previous post: while there is heating, I'm not sure what the implication is for temperature!

reader Nancy said...

I agree this is a great summary about Pavlov (sorry he is "Pavlov" not "Pavlova") and a reminder about his uneasy relationships with the regime. The original article (link in Lubo's post) is also excellent!

Pavlov was extremely fortunate to escape the fate of many of his compatriots (labor camps, executions). At the same time, Pavlov was very unfortunate as he was trapped behind the "Iron curtain" - unlike Igor Sikorsky and Stephen Tymoshenko, both of whom managed to escape the regime and move to the US several years after the Bolsheviks came to power.

I really like enjoy reading and re-reading these remarkable stories. The thought that came to me just now is that it appears that it was Pavlov's religious belief that sort of trapped him inside the USSR.

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