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Higgs Data Could Spell Trouble For Leading Big Bang Theory
ananyo writes "Paul Steinhardt, an astrophysicist at Princeton University in New Jersey, and colleagues have posted a controversial paper on ArXiv arguing, based on the latest Higgs data and the cosmic microwave background map from the Planck mission, that the leading theory explaining the first moments of the Big Bang ('inflation') is fatally flawed. In short, Steinhardt says that the models that best fit the Planck data — known as 'plateau models' because their potential-energy profiles level off at relatively low energies — are far less likely to occur naturally than the models that Planck ruled out. Secondly, he says, the news for these plateau models gets dramatically worse when the results are analyzed in conjunction with the latest results about the Higgs field coming from CERN's Large Hadron Collider. Particle physicists working at the LHC have calculated that the Higgs field is likely to have started out in a high-energy, 'metastable' state rather than in a stable, low-energy configuration. Steinhardt likens the odds of the Higgs field initially being perched in the precarious metastable state as to those of dropping out of the sky over the Matterhorn and conveniently landing in a 'dimple near the top,' rather than crashing down to the mountain's base."
....we just don't know.
The thing that bugs me about a Big Bang Theory is where did this singularity come from? Where exactly is it, in some infinite void? Are there more like it, all oscillating between Exapansion and Collapse throughout eternity? For the Universe, as we know it, is only this local body of mass and energy.
and now i need a quiet corner, cuppa hot cocoa and my teddy bear
A feeling of having made the same mistake before: Deja Foobar
Steinhardt is no novice when it comes to making controversial cosmic claims. For many years, he and some of his colleagues have been developing an alternative 'cyclic model', in which the Universe undergoes a series of Big Bangs and crunches, repeatedly expanding outwards and contracting inwards. Unlike inflation, this framework predicts slight deviations from the smooth Gaussian distribution of temperature fluctuations.
So it's not like he wants to throw out the whole thing, just the "inflation" variation.
Everything is better with chainsaws.
It's not a cosmic catastrophe so much as a physics one, although I'd prefer to call it a physics "opportunity"! Having found the Higgs we already know that there is now an incredible precarious balance even within the Standard Model. The Higgs is a fundamental scalar particle which is a radically different beast from any other fundamental particle we know of. One of the strange properties of the Higgs is that there are corrections to its mass which scale with energy squared.
This might not sound like a big deal but quantum mechanics means that even at low energies these high energy corrections to the Higgs mass are important. The question then becomes "what energy is our current knowledge of physics good to". Well if we look at the Standard Model of particle physics it is missing gravity so, at the scale where gravity becomes important (about a million billion times higher in energy than the LHC) we know the SM breaks down.
The problem is that this means the Higgs mass is corrected by a series of terms each of which is ~32+ orders of magnitude larger than the mass itself. This means that you need a cancellation to better than one part in ~10^32 by chance. This is about the same chance as winning the UK national lottery every week for 4-5 weeks in a row or tossing a coin and having it come up heads over 100 times in a row. If either of these events actually happened nobody would believe they happened by chance - there would be investigations into how someone managed to cheat the lottery or you would want to inspect the coin to make sure it did not have two heads.
There are solutions to this conundrum: Supersymmetry makes all the corrections to the Higgs mass cancel precisely (above some energy scale) and Large Extra Dimensions lowers the scale where gravity becomes important considerably. What would be interesting to know is whether these solutions to the fine tuning problem we have in the Standard Model also solve the fine tuning which this paper suggests that cosmology also has.
Spent all my mod points, but excellent questions. There are, sadly, limits to what we can discover with physical sciences. This has bugged me since I was a kid. I want to know, dammit! The universe is so vast that we will never know or be able to know even a small fraction of what's there. Some questions, as why there is anything at all, will forever be in the realm of philosophy, unanswerable by empirical sciences alone.
But we keep asking, keep looking, both farther and closer, because we have to know. It's in our nature.
I like some was partially hoping they'd fail to find the Higgs, and the experiments would point the way to some more fundamental theory, but it seems our current model is actually pretty good as far as it goes. Although I barely understand particle physics, I'm fascinated by all the research on it, and share the desire to understand the nature of our universe at the deepest level.
But look at me still talking, when there's science to do! (well not by me personally, I have to get back to coding).
my, your, his/her/its, our, your, their
I'm, you're, he's/she's/it's, we're, you're, they're
A bit of background here: the great data we now have on the Cosmic Microwave Background Radiation presents a solid mystery: it's all very nearly the same temperature, yet with steady expansion of the universe opposite sides of the sky would be too separated (by speed-of-light delay) to have temperatures evened out like that.
In order to explain that, "inflationary" models were invented, which proposed that the very early universe expanded quite a bit faster than the speed of light. I don't quite get why expanding faster makes temperatures more equalized, but I don't doubt the math works. There is some actual evidence for inflation: the temperature variations in the CMBR do look a lot like quantum fluctuations magnified enormously. A lot of work has been done in this area in the past decade.
Inventing a new mechanic by which space itself grows very rapidly is easy, but inventing one where the expansion was likely to happen, and happen evenly across the universe, and then stop, is hard. The best candidates are tied to the Higgs field - basically saying it was briefly at a meta-stable state where there was no inertia, allowing rapid expansion, but then the symmetry broke and it reached the current stable state.
The new problem is: all that only works if you assume the Higgs field naturally starts in its metastable state, so even if it's only that way for 10^-lots of a second, that's enough. Apparently, it wouldn't naturally start in that state, and would in fact be quite unlikely to. That unravels everything, because the whole problem being addressed is how unlikely the even temperature distribution of the CMBR is in the first place: a hypothesis that's also quite unlikely to occur naturally doesn't really help much.
Socialism: a lie told by totalitarians and believed by fools.
Your questions are wrong because our human minds are not adapted to handle the truth... which is: there was no time and space prior to the big bang... because there was no time that was prior to the big bang. The Big Bang created time and space. Our best measurements and studies have concluded that the universe will not collapse again. It is in an accelerating expansion. It's not slowing down. There will be no big crunch. Are there other universes? Perhaps... but I tended to think that if there are... they are all part of this one same system. All effecting each other, and therefore all part of this universe just in an indirect way... but then I'm just getting into semantics.
If the evolution of a stable universe requires the Higgs field to start out at a metastable point, and if variations in those initial conditions lead to universes which collapse rather than inflating, then "the amplitude" (i.e. the probability that they are the outcome that we turn up in) for those other states is zero. Why? Because those universes all collapse long before we could show up.
On the other hand, if Steinhardt is correct, then his result shows there is a path to here-and-now through the metastable point, and if that's what it takes to get here, then that's enough: that's what it takes. The amplitude of the entire wave function for the Steinhardt path is non-zero, unlike the functions for the ones that collapsed.