Higgs vacuum stability and fine-tuning

Regular readers of this blog know that I think our reality is probably a massive peer-to-peer (P2P) networked computer simulation (also see here and here). Some of you may also recall that whereas for most of my life I self-identified as a religious Agnostic, I now self-identify not as a Believer but rather as a Hoper--someone who believes it is a serious epistemic possibility that some sort of 'God' exists, and who hopes against all hope (but does not believe) that a good God (one that can somehow redeem this rather wonderful but rotten world) exists (also see here).

I won't go into full detail here as to why I believe a Creator is a serious epistemic possibility, or why I hold out a sliver of hope (though not a ton!) that Creator might be good, or at least good enough to love. Suffice it to say, I think that if our world is a massive peer-to-peer networked computer simulation, it probably had to be made. Peer-to-peer networking--particularly networking on this massive of a level--is incredibly complex and requires an incredible amount of processing power. One of the other reasons I take the 'God' (or, if you prefer, Creator) hypothesis seriously, though, is that (as I've said before) the more I understand about physics and cosmology, the more miraculous this entire world seems to be.

Now, I'm sure you've all heard of the Fine-Tuning Hypothesis before--the view that our Universe is "finely tuned" in a variety of seemingly-miraculous ways. I'm sure you've heard something like the point that if gravity were just a bit stronger, the Universe never would have expanded as it has; and if gravity had been just a bit weaker, it would have expanded so quickly that galaxies, stars, and so on never could have formed. Or maybe you've heard that if the Carbon atom's Hoyle state had been just a wee bit different, life could never had formed. And so on.

I want to share with you another, more recently discovered case of fine-tuning that, I believe, will knock your socks off. You may (or may not) have heard of the Standard Model of particle physics. While the Standard Model is widely thought to be incomplete, it is an exquisitely well-verified model. It makes crazy-precise predictions about what we should observe in particle colliders, and each of the particles it predicts has been observed. Indeed, the final "key to the puzzle"--the only particle the model predicted but had never been observed, the Higgs Boson--was finally observed (decades after its first prediction) just over two years ago. 

The Higgs Boson is a unique particle unlike any other: it is the particle that all other known particles interact with that gives them mass. Without the Higgs, there would be nothing with mass at all! But, here's the really crazy thing. Although the Standard Model did not predict the Higgs' mass, its mass was found to be in literally the most improbable place you could expect to find it. Allow me to explain.

Here is a fun little chart:

As you can see, the Higgs mass was found in a little sliver of the chart labeled "meta-stability." Let me explain what this means. Very roughly, an unstable or non-perturbative universe (red areas) are sort of what they sound like: they are universes that can't possibly work. A stable universe, on the other hand (green area), are universes that work all the time. Finally, there's "metastability" (yellow area), which means that the universe works sometimes but not always. In the metastable area, the Higgs is temporarily set at one value--the value that makes our universe go round--but will someday fall to a different value: yes, that's right, a value with all new physics (since the Higgs will then interact with all other particles in a different way). Not only are we in the yellow area (a place where it is very hard for the Higgs to 'stay'). We are in the almost the littlest sliver of the yellow area: which means that our Higgs will be stable for a super-duper long time, but not always. Someday, the Higgs will change, and our universe will become another--one where, in an instant, none of us, none of our planets, stars, etc. exist. One in which all of physics changes. All in an instant. This is where we found the Higgs boson to be. We found it in the littlest, most unlikely sliver of the most unlikely area to find it.

There is another way to put all of this. Imagine a very steep cliff with almost no jagged edges. If you were to roll a golf-ball toward the edge of this cliff, where would you expect it to end up? Answer: one of two places: either someplace before the edge (i.e. on land before the cliff) or at the very bottom. The chances of the ball somehow stopping on just a tiny jagged edge would the most improbable thing you could imagine--sort of like the very well-known and justly famous cliff-climbing mountain goats:

The observed Higgs value tells us that our universe is like these goats. Or, to use another helpful image, consider an empty coffee cup. If you were to drop an individual coffee droplet out of the sky, where would you expect to find it? Answer: either in the coffee cup, or outside of it. You most certainly not expect to find it perfectly balanced on the lip of the coffee cup for 13.8 billion years, without ever rolling off one side or the other. But this, again, is what our Higgs--our universe--is like. As one commenter writes at a physics blog I visit occasionally:

20 years ago the Higgs mass could have been pretty much anything, but there was one value that was singled out as special: m_H = 125-126 GeV is the boundary of the stability region. Isn't rather remarkable that Nature chose this very special value?

We know that the Lord is subtle but not malicious, but it seems to me that the message that He is now sending is very clear and not the slightest subtle: there is no new BSM physics and the SM is balancing at the brink of instability. Perhaps better to seek to understand this message instead of looking for another class of excuses to ignore it.

UPDATE: For more, see here and here.

Comments

[Elisa Freschi]

Thank you for this very fascinating post, Marcus. A great summary of several other posts of yours, concise and efficacious at the same time.

I am sure that a standard answer would be that even a small chance can indeed happen and that this does not necessarily imply fine tuning (after all, sometimes coins do land on the edge etc.). But let me point to a different approach (you know, I always tend to play the role of the advocatus diaboli;-)): The unicity of the Higgs Boson's position is only exceptional if we think that our universe has a single "life". But try to imagine that the universe is *beginningless and endless* in both time and space-dimensions. Would not it be normal that sooner or later *all* possibilities will be actualised in one or the other dimension?

[Infovoy]

Hi Marcus,

This particular 'fine tuning' is just as susceptible to explanation by a multiverse as the others though isn't it? Do you reject that possibility?

Matt

[Marcus Arvan]

Elisa & Matt: Thanks for your comments!

Yes, it is absolutely possible for such a universe to be explained by a vast multiverse comprising all possible outcomes--in which case, sooner or later, even the most improbable outcomes have to occur.

This is in fact a notion that I have long been very sympathetic to--and it may well be the correct explanation. Nevertheless, it is simply astonishing that we evidently ended up in the most improbable of all possible universes.

One 'instance' of fine-tuning (e.g. carbon fine-tuning) would be remarkable. But dozens of different, independent instances? This is like picking up one coin, flipping it a gazillion times, it landing 'heads' every single time; then picking up a six sided die, flipping it a gazillion times, it landing on '1' every single time; then picking up a twelve-sided die, flipping it a gazillion times, it landing on '11' *every* single time; and so on.

This could be a string of astonishing coincidences. But, for all that, they are absolutely astonishing.

And so allow me to explain one reason why I think a 'Creator' might be a better explanation than the multiverse.

The physicist Max Tegmark has pointed out that there are several different 'multiverse hypotheses' (http://en.wikipedia.org/wiki/Multiverse#Max_Tegmark.27s_four_levels ).

Two of Tegmark's 'types' of multiverses are implications of eternal chaotic inflation (something believed to be true, but still an open question)--with universes 'birthing' new universes beyond the cosmological horizon (as a result of runaway inflation). This kind of multiverse results in an infinite variety of different physical laws. And this is the kind of multiverse you two are referring to.

Another 'type' of multiverse (the one my "A New Theory of Free Will" and other work depend upon) concerns quantum-mechanical decoherence, or 'parallel worlds' branching off from ours at every moment. This type of multiverse is *indexed* to our (quantum) physics, that is, it is an implication of them. In other words, this type of multiverse--although vast--cannot explain our universe's constants. Rather, it is a result of them.

I tentatively believe that because my P2P Hypothesis explains the existence of quantum phenomena, that *if* its predictions are confirmed, we will have very powerful evidence that we are in a peer-to-peer networked computer simulation (with the latter, indexed 'multiverse' of possible space-time positions and choices within the simulation). If we not only found this--that our universe is peer-to-peer networked--*and* we found that the universe is finely tuned in a variety of ridiculous ways, I want to say that although a multiverse of all possible laws *could* still explain this, the better explanation is that our world was Created by an intelligent agent.

After all, consider the perspective of observers living in an online videogame. *They* would be in a position much like we are. They could hypothesize that perhaps their world's fine-tuned values could be explained by an infinite multiverse 'trying out' all possible states and laws. But, of course, when we look at their situation from the outside, we want to say, "Obviously, the best explanation is that *we* created you." Why? Not simply, I think, because we are looking at them and know that we created them--but rather precisely because the phenomena they observe (quantum phenomena, finely tuned physical values) are precisely what you would *expect* if, indeed, they were created by us.

[Marcus Arvan]

Elisa and Matt: It occurred to me that there's another way of putting the concern about the multiverse explanation of fine-tuning.

It would be one thing if some of our universe's parameters to be fine-tuned to some unlikely value (namely, those necessary for life, etc.). It would be another thing for many parameters of of our universe to be fine-tuned. But, it is another thing entirely for literally *every* parameter found so far appears to be fine-tuned to unlikely values (including those not essential for life, such as vacuum metastability--as there are far more stable values for the Higgs than metastable ones).

To put this another way, yes, if you roll enough golf balls off a steep ledge, sooner or later one will fall (and stay) on a little outcropping (like mountain goats). That wouldn't be very shocking. But our universe is a bit more like *every* golf ball rolled off a steep ledge perching on the most precarious position possible, with *none* of them at the bottom of a cliff. Or, to use the coffee cup example, it is rather like finding no drops of coffee either in the cup or outside of it, but rather *all* perched on the lid. Such a coffee cup is of course possible (if we consider every possible state of affairs)--but this does not detract from how astonishing it is: of the great many coffee cups out there, it is literally THE most improbable one.

That is what is so shocking. It's not that our universe wouldn't exist in a vast multiverse of infinite possibilities (it would). It is that it appears to be something like the least likely universe of all in the plurality of possible universes.

[Infovoy]

Hi Marcus,

I think your interpretation of the different types of multiverse is the standard one (although Susskind suggests they may all be equivalent here: http://arxiv.org/abs/1105.3796 / http://www.technologyreview.com/view/424073/multiverse-many-worlds-say-physicists/), so I'll go with that.

However, I'd interpret the fine tuning cases in a different way. To take your analogy of the golf balls and the cliff, each ball represents some fine-tuned property (ftp), which means that to represent a whole universe we need to roll each ftp ball towards the cliff (along with a load of non-ftp balls that we don't care about here) and wait for them all to stop. We then take a snapshot of the position of all the ftp balls and call this entire snapshot a possible universe U1. We then do this again and again so we have U1 to Ux (where x is the number of possible end states for the ftp balls in combination).

When we've done this so that we have every possible combination (minus any duplicates - we'd not really be rolling the balls to work this out of course!) we'll have a small subset of universes where one or more ftp balls are perched on the cliff (each ftp ball has a smaller or larger range of perching values). There will be an even smaller subset where every ftp ball hit a value in its acceptable perching range, and it's *this* subset that is amenable to our being here.

You reference this amenability as being "another thing entirely for literally *every* parameter found so far appears to be fine-tuned to unlikely values". But isn't it just another subset? a smaller one for sure, but not "another thing entirely". The anthropic principle still says that since we do exist there is no possible way we could be in anything but that tiny subset, no matter how 'unlikely' it appears.

Does that makes sense, or am I missing something you're getting at here?

Matt (infovoy)

[Sylvia]

Dear Marcus,

I really liked your post - combining physics and mountain goats :) -, but I am not convinced yet.

* You refer to a "little sliver of the chart" and you seem to interpret the ratio of yellow to total area of the chart as a probability to end up in that part of the chart: "its mass was found to be in literally the most improbable place you could expect to find it". I do not agree with this interpretation, since the areas and the associated ratio depend on the choice of parameters. (Physicist use many scales for energy, which are not all linear to eV.) An instance of the paradoxes of equiprobability is just around the corner... ;)

* You suggest that something that is metastable will change: "which means that our Higgs will be stable for a super-duper long time, but not always. Someday, the Higgs will change, and our universe will become another". Diamond is a metastable form of carbon under standard temperature and pressure, but still De Beere's slogan "A diamond is forever" sounds acceptable, since we don't expect to see diamond turn into another form of carbon in our life time. In principle, a metastable state could outlast the age of the universe. I don't know how to estimate the expected lifetime of the metastable state of a Brout–Englert–Higgs particle, but if we assume the expected lifetime of the universe is finite, it may be longer than that.

[Elijah]

Fascinating post, but could you clarify why a metastable universe is more confirmatory of a creator? It seems to me that a creator would prefer a stable universe, but I may be missing something.

[Marcus Arvan]

Hi Matt: Thanks for your reply.

I've come across Susskind's suggestion that all of the multiverse hypotheses may be equivalent before--but I just don't buy it. The Everett interpretative indexes the number of multiverse worlds to possible solutions of the quantum formalism--but this is a very small subset of all possible universes: namely, all of those universes that have different quantum-mechanical properties.

Indeed, I think we can see the difference plainly by considering the peer-to-peer simulation hypothesis I defend. Each individual videogame has its own "multiverse"--i.e. possible states of affairs given the game's programming. But it is simply a mistake to take the plurality of possibille universese for one game (the multiverse for halo) to be identical to the plurality of possible universes for other games (Call of Duty), or indeed, the plurality of possible universes for all possible videogames.

In any case, you are right that, in a plurality of possible universes, there *will* be one where every parameter is finely tuned (i.e. such parameter settings are indeed subsets of all possible parameter settings). Nevertheless, I still do think--in a manner of speaking--the Higgs fine-tuning is "another thing entirely." Whereas many other fine-tuned variables appear necessary for life--and so would be perfectly expected by the anthropic principle (expected for any universe we might find ourselves in)--the Higgs value does not appear to be this way. It appears to be almost (almost!) impossibly improbable *given* a universe with life like ours. This is the sense in which it seems uniquely improbable. There couldn't be a universe with life like ours without carbon's Hoyle state. There could be (or so it seems) bazillions of universes with life like ours and a different (stable) Higgs mass, and yet we found ourselves in what seems appears (a priori) to be the most improbable one of those universes.

[Marcus Arvan]

Hi Sylvia,

Thanks for your comment! You're certainly right that diamonds are (only) metastable, and that in principle a metastable state could outlast the age of the universe (though I'm not entirely sure this makes sense, since it seems to me that time must be infinite in duration, or at least a finite but closed loop). My point, though, was simply that metastability is a priori unlikely--that there are vastly more Higgs-stable universes than Higgs metastable ones, and that even in the metastable parameter space, it is in one of the most improbable regions.

[Marcus Arvan]

Hi Elijah,

Good question--and I'm not sure I have a great answer. The basic idea is that the more improbable the world is--the more we find the the world's parameters *could* have been one way, but instead occupy the most improbable values across a range of phenomena--the more reason we have to think that something fishy is going on. If you found one pile of rocks on a path in the shape of an arrow, you might reasonably chalk it up to happenstance. If you found two sets of rocks miles apart pointing in the same direction, you still might do so. If you found not only rocks shaped like arrows, but also arrows carved into trees, and so on, you would probably get suspicious that something fishy is going on. It *could* all just be chance, but all the same, the *chance* that it is just chance seems progressively smaller the more improbable coincidences one finds.

This is especially true if you think, as I do, that quantum mechanics *itself* is plausibly evidence that we live in a peer-to-peer simulation. But of course this is just my own position.

In any case, to address your positive suggestion, "it seems to me that a creator would prefer a stable universe, but I may be missing something"--there are a number of (admittedly speculative) reasons why a creator might have made a metastable universe. One reason might be to leave "breadcrumbs" to us that the world was created (along the lines of my suggestion above, that the more coincidences one finds--along with perhaps the best explanation of quantum mechanics being that we are in a simulation--the more probabilistic evidence we might have of creation). Another possible reason for creating a metastable universe might be to create different epochs. It is, after all, a fundamental part of most major religions that the world will be one way (Fallen/Imperfect) for a very long time, but then someday fundamentally change to a more perfect state. It could be that metastability is a burning wick of sorts to fundamentally alter the constitution and function of the universe--but of course this is pure speculation (as is all this stuff, admittedly:).

[Infovoy]

I take Susskind to mean that the smaller multiverse subsets form parts of the full multiverse set – I could be getting that wrong though, would need to re-read.

Anyway, it’s a side issue to what you’re getting at here I think, and I do see your point now. I’m going to have a look into this – I think it’s mentioned in Smolin’s Time Reborn…

[Marcus Arvan]

Hi Matt: I don't think Tegmark (or anyone else) has ever denied that the smaller multiverse worlds comprise a proper subset of the larger multiverse. This, in fact, is trivially true. 'Some possibilities' are, by definition, a proper subset of every possibility.

[Kevin v]

Hello,
I was curious if there are other examples fine tuning like this; in the least probable place you would expect to find it?