Sunday, April 04, 2021
An April Fools' Day paper on the swampland rules
On April 1st, 2021 various individuals and companies came with their April Fools' Day pranks, see e.g. this thread where I found the Cybermouse to be particularly well-made. Some scientists have also posted preprints that weren't meant as a serious contribution to science. One of them was from William Kinney, a cosmologist in Buffalo:
The point of the paper is clearly to humorously express the author's opinion that the number of papers about the swampland is too high. The detailed jargon-filled, science-like-sounding propositions aren't hard to invent in real time, I would probably end up writing a similar April 1st paper if I wanted to express the same point (although I hope that mine would be funnier).
But is the serious point conveyed by the satirical paper correct? Is the number of the swampland papers too high? I don't think so. First, the "meme" and the very general foundations of this research were articulated by Cumrun Vafa – who had an office next to mine when he wrote it – in 2005: The String Landscape And the Swampland. The paper has 548 citations as of now.
Months later, I managed to submit the first hep-th paper of 2006 where we accumulated the evidence that the gravitational interaction is the weakest one not just in this real world but in any world described by a consistent quantum mechanical theory including Einstein-like gravity. The Weak Gravity Conjecture (WGC) is at 795 citations now. It is higher than Vafa's original, "visionary" paper, perhaps because the visionary paper is a bit too vague and popular in character (a big wave of anti-string crackpots was just emerging and Vafa clearly stood on the same side as your humble correspondent; I think that the swampland paper was partly motivated by these interactions outside "quite professional science") and the WGC contains a bit more beef.
At any rate, we are talking about fewer than 1,000 papers that had a reason to refer to these two swampland papers. Only a smaller portion of them, a few hundreds, actually propose some entirely new swampland criteria or variations of some criteria in the literature. There are just a dozen of "truly different, new" swampland conditions as of now, I believe.
But let's ignore the degree to which the papers may be rightfully referred to as "papers about the swampland criteria". Even if we are generous, the total number doesn't surpass 1,000. How much has mankind paid for this research? The average swampland researcher (in the world) may be getting some $40,000 a year, he or she writes 4 papers a year. Research is done for 1/2 of his funding (he may also need to teach etc.) but this factor of 2 gets canceled by about 2 authors of a paper in average. So a swampland paper may cost some $10,000 to be made and there are a thousand of them.
So the swampland research has only cost something like $10 million, a ludicrously tiny amount of money. I think that a person who would propose that this is too much for this rather rare direction of research is a Luddite animal and enemy of the things that place the human race above other species. Make no mistake about it: If you would like to reduce this number further, you are a scumbag. Just to compare: tens of billions have been spent for the "research of climate change" that hasn't really taught us anything reliable yet new enough and that has only served to make some insane, far left projects in politics look more sciency. A trillion has been wasted for the misguided policies recommended along with the "climate research". And that's nothing compared to the totally pointless Covid lockdowns that have erased about $10 trillion from mankind's wealth (10% of the world GDP). The swampland has been 1,000 or 1,000,000 times cheaper than the "climate change research" or "lockdowns", respectively!
These costs are trivial which means that the only legitimate, similar question is one about the relative attention that is dedicated to the swampland (or the WGC) if this topic is compared to other things that these fundamental enough scientists can make. And it's simply true that there aren't too many things that are similarly, rightfully exciting as the swampland.
What I found amusing were the recent papers by this very Dr Kinney. The most recent 3 have 0,0,1 citations, respectively. The fourth newest paper has 17 citations, quite a difference, and it is about the trans-Planckian censorship. If you look at it, you will realize that it is really a swampland paper itself! ;-) Kinney has actually written 3 serious papers with "swampland" in the very title and they have 12,53,133 citations as of now, respectively.
I guess that his own swampland papers end up being more successful than his other recent papers and he knows it. Is this success justified?
I think so. The real point is that the swampland is still a "new enough conjecture" and that is why it is so provocative for various people. But one paper co-authored by Kinney is titled "Primordial Non-Gaussianity" which I pick as my benchmark to be compared with the swampland.
Every professional (or graduate student) in the field of cosmology knows what it means. A fun fact that is easily overlooked is that the "primordial non-Gaussianity" is a conjecture, too, just like any swampland conjecture proposed in the literature. No statistically significant deviations from the Gaussianity have been observed but there are obvious reasons to think that the distribution shouldn't be precisely Gaussian. Various paradigms and/or detailed models have various reasons to predict a tiny non-Gaussianity or a substantial one (if they predict too much, they're excluded). The character of the argumentation in similar papers is really analogous to the argumentation in the swampland papers. And there are papers that actually talk both about the swampland and about non-Gaussianity, these concepts really belong to "almost the same subfield".
You may search for all papers that contain non-Gaussianity and primordial and my Google Scholar shows over 9,000 such papers (some are important enough experimental searches for such non-Gaussianities). So the number of such papers almost certainly is much higher than the number of papers about the swampland. Kinney could write a satirical paper about the excessive attention dedicated to the primordial non-Gaussianities and it would be about 10 times more justified than the satirical paper about the swampland but he didn't. Are the new thousands of papers mentioning the primordial non-Gaussianity bringing us more value than the new swampland conjectures? I don't think so.
It is really great that new swampland criteria are being invented when people see some new patterns in the data and theories describing the Universe at the fundamental level. This approach, a form of "pattern recognition", has simply become a new methodology favored by many professionals. It is what makes this topic more creative and intellectually diverse than the discussion of the primordial non-Gaussianities – which are really a straightforward possible effect that may be either stronger or very weak.
To summarize, Kinney's satirical paper is somewhat funny but if or when there is a possibility that the reader extracts a message from the paper, one must say that this satirical paper is extremely demagogic, too. The swampland program is an example of a new enough, creative enough topic with quite some potential for progress and breakthroughs. To say the least, it makes many researchers genuinely excited – which isn't the case of the 9,071st paper describing the similar basic possibilities concerning the non-Gaussianities in a slightly different way. Why are the swampland conditions and WGC interesting? Because, as people see, they look analogous (especially) to the Heisenberg uncertainty principle which symbolized the most important revolution in the history of science – but unlike Heisenberg's principle, the swampland ideas aren't fully understood yet. When there is evidence for "something important" that we don't understand, real scientists (and curious people) focus their eyes, ears, and neurons.
More generally, ideas that came from string/M-theory or that were quickly tested within the string/M-theoretical framework simply are more intriguing according to the actual researchers and that is why the actual researchers must be allowed to focus on them. They know why they are excited if they are excited and a demagogic satirical paper simply isn't a legitimate counterargument to these reasons for excitement.