Over the past year or so, as public awareness has grown that string theory is a failed idea about unification due to its inherent untestability, I’ve been surprised by the way in which many in the string theory community have chosen to deal with this. Instead of just honestly admitting what the problems are and describing the sensible reasons to keep working on string theory despite them, some have decided instead that the thing to do is to go to the press with misleading and dishonest claims that string theory really is testable.
The endless examples of this in New Scientist are probably best ignored, but this week’s example is being promoted in the highly respectable journal Nature. It’s all based on this letter to Nature from a group of condensed matter physicists at Lancaster University, now prominently highlighted as an “Advance Online Publication” at the Nature Physics web-site. The authors describe an experiment in which they manipulate the boundary between phases in a superfluid, showing that when such boundaries come together, one gets left-over in the remaining phase the well-known topological defects that one would expect.
The Nature letter itself makes rather ridiculous claims that this kind of otherwise unremarkable phenomenon is somehow closely related to brane cosmology and string theory. The authors do note that
The precise correspondence between the 3He phase interface and a cosmological brane is still a matter of discussion, the closest correspondence probably being to the D-brane. For the present purposes we may note that the correspondences are as much topological as specific.
While the letter makes no explicit claims about “testing” string theory, the press release issued by Lancaster is the usual sort of dishonest nonsense:
Low-temperature physicists at Lancaster University may have found a laboratory test of the ‘untestable’ string theory.
The test – which uses two distinct phases of liquid helium – is reported online this week in Nature Physics (published 23 December). Their paper will also be published as the cover article in the paper edition of Nature Physics in January.
String theory is a multidimensional theory based on vibrating strings, as opposed to the point particles described in the Standard Model.
Within string theory, a brane is a large surface embedded in higher dimensional space — our Universe could occupy such a brane.
A collision between a brane and an antibrane can leave behind topological defects, including perhaps the Big Bang itself. But however elegant this theory, it makes no falsifiable predictions, or at least none using current technology.
Richard Haley and the ULT Group have taken a lateral step to address this barrier….
Similar wording is used in a press release put out by Nature about this.
Nature has a relatively reasonable news story by Geoff Brumfiel about this, but also an article by string theorist Cliff Burgess hyping string cosmology (“The subject of string cosmology is a hot one these days, with theoretical advances in understanding string dynamics riffing with recent precise observations of the cosmic microwave background”) and the relevance of the Lancaster group’s work to it. He mostly sticks to hype in its pure form, just devoting one paragraph to the actual scientific result. There he ends up acknowledging that this actually has nothing to do with string theory in the following rather ludicrous way:
The quality of the details of the comparison between 3He and cosmology is not really the point. Like a tap-dancing snake, what is amazing is not that it is done well, but that it is done at all.
After this he shifts gears to start hyping AdS/CFT, without mentioning that this has nothing to do with the Lancaster group’s claims that he is writing about.
The whole point of this kind of exercise is to generate misleading articles in the press that will convince some people that string theory really is testable. This seems to be working well, there’s already one entitled “Test tube universe” hints at underlying theory in the Telegraph, which tells the public that:
A “universe in a test tube” that could be used to assess theories of everything has been created by physicists…
The Holy Grail of physics is to establish an overarching explanation to unite all the particles and forces of the cosmos. But one of the complaints commonly levelled at a leading contender for a “theory of everything”, called string theory, is that it is impossible to test.
But now, according to the study in the journal Nature Physics, it may be possible using the universe in a test tube. “It was a serendipitous discovery,” says Haley…
For the past three decades it has been known that strings are one member of a bigger class of objects called branes, which exist in higher dimensional space, that could be extended in more than one dimension – from strings of one dimension, to membranes of two dimensions, to those of p dimensions, dubbed p-branes. Moreover string theories and p-branes are facets of one underlying 11-dimensional M theory, which suggests that we live in a brane world: a four-dimensional surface, or brane, in a higher dimensional mixture of space and time.
People and most particles move in the brane, while the higher dimensions provide a framework to unify all forces, from gravity to those that act between atomic particles. While experiments have begun to highlight cracks in the current best theory, called “the standard model”, there is evidence that M theory’s extra hidden dimensions could be revealed next year when a Geneva atom smasher – the £4.4 billion Large Hadron Collider – begins experiments. But the Lancaster team offers another route to address this impasse.
Update: Wired Science has an article about this entitled A Test for String Theory After All? Or Just PR?, which shows excellent judgment by linking to this posting…
On the scientific front, it’s worse than I thought. There a conference in London at the Royal Society next month on Cosmology Meets Condensed Matter, where the head of the Lancaster group will speak, and the idea that “coherent phase boundaries mimic branes” is listed as one of the four justifications for the conference. I guess this emerging new field might best be called “Squalid-State Cosmology”.
Update: David Appell has a posting about this, which includes a quote from Witten:
There is definitely no test of string theory here.
Unlike me, Witten goes on to try and find something positive to say about this.
Update: Physics World has an article about this entitled Cosmic strings in a test tube? In the short article, one of the physicists working on this Richard Haley, is twice described as denying that this is a test of string theory, and Grisha Volovik is “adamant that the work is neither a test of sting [sic] theory…”. Despite these firm denials, the press release from Lancaster about a test of the “untestable” string theory is still up.