21.12.2015

Nicolas Gisin

Nicolas Gisin, an eminent figure in the field of quantum foundations and quantum information who most of our readers will be familiar with, recounts the incident of an unsuccessful publication by two of his students  – on arXiv. The story has disturbing implications. It seems that scientific communication through self-publication on arXiv is not as free as it appears to be.

Nicolas’ dark tale is also a call to arms. Willful and unfounded rejection of publications on arXiv goes against the basic principles of the platform, and it is something we should under no circumstances be willing to accept. So, if you have had similar experiences, tell us of them. Share this story with us. And then, let us prepare a strategy to keep arXiv (and perhaps similar platforms) free of such repressive influences.

With his background in both academic physics research and telecommunications industry, the double ERC-Grant winner and first recipient of the John Stewart Bell Prize Nicolas Gisin is certainly one of the most prominent authorities in the field of quantum information research today. His book Quantum Chance has appeared in many languages, including English, German, Chinese, Korean and Russian. One thing Nicolas is particularly proud of is his success in the area of field hockey. He has been a top level national player and served as president of Servette HC from 2000 to 2015, during which time he brought the club to fame and recognition.

Thank you, Nicolas, for this alarming contribution.


Thought police – on arXiv?

By Nicolas Gisin

I think very highly of the arXiv. I use it extensively and I am one of the most prolific contributors. I always thought it’s a marvelous open preprint server, allowing all (non-offensive) ideas to be exchanged in almost no time. Yet, recently I was shocked to learn that things are not always like this, as the story below shows. Given the enormous importance the arXiv has for our work, I feel it is my duty to bring this story to the attention of my colleagues. I hope it is a singular event, but I cannot be sure. What about you? Any similar experiences?

I am of the generation that, as a teenager, read “1984”, the book written by George Orwell in 1949, which predicted that by the year 1984 we shall all be under the continuous surveillance by a “Big Brother”. At the time, very few people believed that this could be anything but pure science fiction. Well, today we know that Orwell’s main mistake was that there is not one Big Brother, but several.

But in our scientific community we managed to preserve a space of peace and freedom. Isn’t it? We can freely meet at conferences and workshops, we can freely exchange information per e-mail, blogs and preprint servers. Really?

In 2014, two of my students came to me with a strange paper they wrote during their free time. The paper was strange in several aspects. First, because it was a paper on black holes and Hawking’s radiation, while the two students were working – successfully – on their PhD in experimental quantum optics. Next, because the paper’s main conclusion was that one can’t fall into a black hole: thanks to Hawking’s radiation, the black hole would evaporate before one crosses the event horizon. I am not an expert in this field and, frankly, have the feeling I never truly understood general relativity. I believe the paper is wrong, but I appreciated my students’ eagerness to transgress barriers established between different subfields of physics. Thus I tried to read their paper. It was clearly written, respecting the usual scientific style. Nothing offending, nothing to argue about the style. The content was a relatively simple calculation, using well admitted formulas for Hawking’s radiation and the Schwarzschild model of black holes. Admittedly, the mass of the black hole was supposed to be time dependent, because the Hawking radiation continuously evaporates some of the mass. Hum, the paper must be wrong, I thought, but I did not spot any simple mistake. I asked several colleagues to help. All agreed that the paper must be wrong, but none spotted any mistake.

My students decided to post their paper on the arXiv, in the gr-qc section with a link to quant-ph. The paper did not appear. After a couple of weeks they wrote to the arXiv and got a sibylline reply: your paper is on hold. No explanation, no reason. Ok, let’s wait. After several months came another e-mail: your paper has been rejected from the arXiv. Oops! I didn’t even know that this is possible. At least not for a paper written in a non-offending and clear scientific style.

During my carrier I posted more than 300 preprints on the arXiv, all in quant-ph. Actually, I might possibly be the most prolific contributor to the quant-ph section. You may consider this as positive or negative, but for sure I feel that the arXiv belongs also a little bit to me. Note that almost all my papers ended up in respectable scientific journals. I am a kind of respectable physicist.

After my students’ paper got rejected without any word of explanation, I wrote to some colleagues I knew are involved in handling the arXiv. Some merely apologized, claiming it’s out of their control. I learned that there is a chairman chosen by the scientific advisory board, but I don’t know who chooses the advisory board. The chairman sent me a short e-mail stating that that’s it, there is nothing to discuss and that there is a list of possible reasons for rejecting papers from the arXiv. Here is the list (http://arxiv.org/help/moderation):

  • Inappropriate format.
  • Inappropriate topic.
  • Duplicated content.
  • Submission of copyrighted material.
  • Excessive submission rate.

Clearly none of these reasons apply to my student’s paper. Hum, I started to get worried. Not worried that the paper might be wrong; such things happen. A much more serious worry: that arXiv might have fallen under the control of people allowed to make arbitrary decisions. Indeed the rejection e-mail, received months after submission) said: Your submission has been removed upon a notice from our (anonymous) moderators, who determined it inappropriate for arXiv.

I guess that people behind the arXiv would claim that their decisions are not “arbitrary”. The paper was surely rejected on “some grounds” (be they scientific or otherwise). But it certainly seems highly problematic that in the rejection email, it was neither stated which of the 5 rules was violated by the submission, nor was there a disclosure of any “hidden” criteria according to which the decision was made.

In the mean time I suggested my students not to worry too much and merely send their paper to a journal. They did so and got the usual kind of referee reports. One positive and one requiring they repeat their calculation using a different metric (the so-called Vaydia metric). Fine. They did the required additional calculation, confirming their initial result and the paper got accepted and published [Physics Letters A 379, 2441 (2015)]. Now, at least and at last, everyone can judge whether the paper is properly written according to scientific standards.

The same two students wrote a second paper, still on cosmology but this time the result was totally uncontroversial. Essentially, they simplified the proof of a well-accepted result. Again they submitted their preprint to the arXiv. This time they didn’t had to wait long. Their second paper got immediately and definitively rejected! Clearly they are now on a black list. Their crime being that they submitted a preprint, possibly wrong but clearly scientific, with a conclusion that some people considered as offending. Nothing personal of course, but seemingly the mere idea that one can’t fall into a black hole deserves to be punished by being banned from the arXiv. No judgment, no argument, no explanation, no discussion. And also nothing constructive came out of my inquires. Oops! By then I got truly scared.

From the scientific point of view, it is likely that the paper is wrong, though I still don’t know where the mistake is. Possibly it is simply an illustration of the fact that general relativity and quantum theory contradict each other when applied to black holes. Hence, everything and its opposite can be derived by some combinations of these two theories applied to black holes. Indeed, it is well known that from contradictory assumptions, everything and its opposite can be derived; and our two pillars of modern physics are incompatible. Hence, a theory of quantum gravity is needed. But in the meantime, personally, I find it interesting to find examples that illustrate the challenges of quantum gravity. Though, this is not my research program.

From the sociological point of view, I strongly recommended my students to no longer work on general relativity and cosmology, but instead concentrate on their PhD in quantum optics. I also recommended that they should not come back to general relativity before having found a mentor, someone able to protect them in this community which seems much less friendly than my quantum information community.

Why should anyone worry about this story? We live in democracy and, overall, the arXiv functions pretty well. As is commonly known, democracy is the worst of all political systems, besides all others. For sure, democracy doesn’t guarantee that good people get elected. But democracy has one immense quality: it contains a mechanism to get rid of truly bad leaders. This raises the following question. In case the arXiv gets dominated by a group of people the physicists’ community doesn’t like, how could we get rid of them?

Let me make clear that I do not think we reached such a bad situation. The people there are certainly doing their best, though I don’t understand how they were chosen, nor how they operate. But shouldn’t we make sure that nothing truly bad could happen, neither today nor in 2048?

Vienna Quantum Café


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