Before I became Physics Today's online editor, I ran the magazine's Search and Discovery department. For seven years, it was my responsibility to make sure that Search covered the most important and interesting research in the physical sciences.
In that span, Search ran just two stories about string theory:
- "Lovely as a Tree Amplitude: Hidden Structures Underlie Feynman Diagrams" (July 2004)
- "A String-Theory Calculation of Viscosity Could Have Surprising Applications" (May 2005)
The first story, by Steve Blau, described work by Ed Witten, Freddy Cachazo, and Peter Svrcek. In 2003 Witten had discovered a mathematical connection between a certain type of string theory and a certain regime of quantum chromodynamics. What prompted the news story was the three theorists' use of that connection to simplify some QCD calculations.
The second story, again by Steve Blau, was similar in character. In 2001 Dam Son, Giuseppe Policastro, and Andrei Starinets had found they could tackle certain problems in plasma dynamics by combining Juan Maldacena's famous duality with hydrodynamics. The story was prompted by Son, Starinets, and Pavel Kotun's extension of that previous work to derive a general lower bound to a fluid's shear viscosity divided by its entropy density.
Given string theory's high ambition to account for all nature's forces and particles, given the number of string theorists working to achieve that ambition, and given the general public's interest in string theory, two stories in seven years might seem low. But is it?
A typical Search story describes results that significantly advance a field and are of potential interest to all Physics Today's readers, from acousticians to x-ray astronomers. My colleagues and I don't avoid covering difficult papers, nor do we oversimplify the essential physics when we write our stories. In his news story about the 2009 physics Nobel, Bert Schwarzschild did not brush Yoichiro Nambu's and Makoto Kobayashi and Toshihide Maskawa's theoretical achievements under the carpet.
But when we ask our readers to follow a technical story—one that we've struggled to make as accessible as possible—they deserve a payoff for investing their time. Speculative theories whose prospects for vindication are remote don't quite deliver.
There's another, more mundane explanation for the dearth of string theory news in Physics Today. Search stories tend to be about one or two papers. In fields where significant individual advances are hard to spot, the expert-written feature article is often the better editorial option.
During my spell as head of Search, Physics Today published three feature articles on string theory: "The Cosmological Constant Problem" by Tom Banks (March 2004), "Solving Quantum Field Theories via Curved Spacetimes" by Igor Klebanov and Juan Maldacena (January 2009), and "What Black Holes Teach about Strongly Coupled Particles" by Clifford Johnson and Peter Steinberg (May 2010).
Now it's quite possible that by some objective, but hard-to-define, yardstick, Physics Today has under-covered string theory. On the other hand, the question that forms the title of this post is one I had to ask myself. None of the hundreds of physicists I've been in contact with over the years ever posed it to me.
Charles Day
The fact that Physics Today avoided speculative theories whose prospects for vindication are remote don’t quite deliver seems rather natural and would not perplex anyone. The fact this editor needs to explain this to readers is what would really surprise us all!
Thanks, CfCS, for your comment. Keep in mind that Physics Today’s website has a wider readership than its print issue does. A lot of online readers are scientists, but not physicists.
Thanks by your useful remark. I incorrectly supposed that recent popular books by Roger Penrose, Lee Smolin, and Peter Woit provided to general readers a fair presentation of the real status of string theory, but your response may mean that I was mistaken and that more info is needed.
String theory has become controversial in large part because certain publicity-seeking individuals decided to take their criticisms to the wider public. Peter Woit and Lee Smolin are not taken seriously by the theoritcal-physics community; indeed, the former is not a professor and has few if any publications, his claim to fame being a blog. Only Penrose is an esteemed figure in the theoretical physics community, but he hasn’t produced important results in decades, and his work in “quantum neuroscience” makes string theory look grounded and rigorous; he’s throwing stones in a glass house.
There are two reasons a person might be excited about string theory: That it might make testable predictions, or that it generates ideas for other areas of physics and mathematics. It hasn’t made a single definite, direct, testable prediction, but many major new ideas in high-energy theoretical physics over the last few decades have had their origins in string theory, and physicists are hoping that we might see evidence of some of those ideas in experiments in the near future. Examples include supersymmetry (born from string theory in the 1970s) and brane worlds (born from string theory in the 1990s).
String theory has also revealed enormous insight into conventional quantum-field theories and condensed matter systems, insights that would have been difficult to spot had people been looking for them directly in their respective disciplines. The tools from string theory have provided staggeringly powerful tools for analyzing these systems, and insofar as string theory has enlarged our toolkits for conventional particle physics, that’s been very helpful.
That latter reason is why string theory has become a key part of the curriculum for grad students in theoretical physics. Most of those students won’t go into string theory, but the tools they learn there and the extra intuition they develop can often be extremely useful in other subjects.
So it’s well worth reporting articles that use string theory to reveal things about other areas of physics, apart from articles that address the long quest to use string theory to make its own direct predictions about quantum gravity.
String theory is so abstract that it is hard to understand it in real physical terms, i.e. no dimension, no size, no enrgy of a unit string, etc.
String theory is logically inconsistent theory, because it considers Lorentz symmetry and existence of extradimensions, which would manifest just with violation of Lorentz symmetry.
STRINGS ATTACHED — James Ph. Kotsybar
Physicists foresee a utopia (once they squint through micro-myopia) where all of the forces of nature should become unified and be understood. Even in science, letting go is hard, and notions are the hardest to divorce, but, to reach there, they’ll have to discard their classical point-particles of force.
While Newton works large-scale, his physics fail, and even Einstein’s theories can’t subsist, when applied to the sub-atomic scale. The answers they produce just can’t exist.
Particle physics, in quantum foam, sank, when its researchers walked the length of Planck.