## Thursday, 29 March 2018

### Write that printing money creates wealth, get published in Nature

In the debate about the carbon footprint of cryptocurrencies, Nature has recently published a one-page correspondence titled “Cryptocurrency mining is neither wasteful nor uneconomic”. This counter-intuitive claim provoked me to read the text in search of a non-trivial idea. To my shock and horror, the only basis for the claim is the trivial wordplay of using the same term “wealth” for both money and goods and services.

## Monday, 26 March 2018

### Springer threatens to go rogue, and retreats

In its negotiations with Springer, the consortium Couperin that was in charge of most French researchers’ subscriptions had been modestly asking that Springer renounce “double dipping”, i.e. does not get paid twice for the same articles – once via subscriptions, once via open access APCs. But this would have meant decreasing subscription prices by 15%, while Springer has been used to yearly increases of the order of 3-5%.

Today’s news are that negotiations have broken down, and most French researchers are set to lose legal access to most articles published by Springer on April 1st. (See CNRS’s note on the subject, in French.) In such a conflict, researchers can stand up against the publisher by
• not complaining when they lose access to journals, and getting the articles elsewhere (which nowadays mostly means at Sci-Hub),
• boycotting the publisher, i.e. not submitting articles to its journals, and not working for them as a referee or editor.
Coincidentally, I have received an invitation to referee an article for JHEP, a journal published by Springer. I have declined as follows:
Most French research institutions are set to lose access to Springer journals on April 1st. I am aware that this does not affect access to JHEP, which is covered by SCOAP3, and that in our field all articles are on arXiv anyway. However, as a matter of principle, I would like to protest Springer’s extortionate commercial practices, and to show solidarity with colleagues who will lose access to their own work. Therefore, I am suspending all new collaboration with JHEP, and I am declining to review this article.

Update on April 3rd: According to an email from Couperin, access to Springer journals has in fact not been cut off. It seems that Couperin got away with rejecting Springer's latest offer, and saying that they were willing to continue negotiating. So Springer was bluffing, and does not dare take a hard line against Couperin. If such a weak and ill-prepared consortium, with little support from researchers (who else is boycotting Springer?) can defeat Springer, pretty much anyone can.

Update on April 11th: There is now a petition called "Springer, we can do without".

Update on October 18th: An agreement has been found between Couperin and Springer. Couperin boasts that it has obtained a modest price decrease: this merely reverses a few years out of several decades of unjustified increases. And the 9-10 months where Couperin's member institutes kept access to Springer journals without a subscription, will eventually be paid retroactively. (Except for institutes who did not accept the new agreement.) Still, Springer's behaviour is not too bad for a predatory publisher. And the price decrease is in absolute terms a large amount of money, which could make much difference if it was injected into frugal publishing platforms. So I am no longer boycotting Springer.

Couperin is now negotiating with Elsevier, aiming to achieve comparable savings, and pushing for open access. Nevertheless, it is not clear to me how Couperin's deal with Springer, and negotiating stance with Elsevier, are compatible with the Plan S to which CNRS officially subscribes: if Couperin believed in Plan S, it should at least refrain from committing beyond 2020, the date at which Plan S is supposed to come into force.

## Tuesday, 20 March 2018

### The open secrets of life with arXiv

If you only think of arXiv as a tool for making articles openly accessible, consider this: in 2007, a study showed that papers appearing near the top of the daily listing of new papers on arXiv, will eventually be more cited than papers further down the list – about two times more cited. And there is a daily scramble for submitting papers as soon as possible after the 14:00 EDT deadline, in order to appear as high as possible on the listing. The effect is not as perverse as it seems, as there is no strong causal relation between appearing near the top and getting more citations. (More likely, better papers are higher in the listing because their authors want to advertise them.)

The consequences of arXiv’s systematic use in some communities are actually so deep that a speciation event has occurred among researchers, and a new species of arXivers has appeared. Here I will try to explain how arXivers live, in order to help non-arXivers understand arXivers, and have an idea of what could happen to them if the currently proliferating clones of arXiv gained widespread use.

## Thursday, 1 March 2018

### Uniqueness of Liouville theory

The original definition of Liouville theory by Polyakov in the 1980s was written in terms of a Lagrangian, motivated by applications to two-dimensional quantum gravity. In the 1990s however, Liouville theory was reformulated and solved in the conformal bootstrap approach. In this approach, the theory is characterized by a number of assumptions, starting with conformal symmetry. In order to actually define the theory, the assumptions have to be restrictive enough for singling out a unique consistent theory.

After assuming conformal symmetry, it is natural to make assumptions on the theory’s spectrum, i.e. its space of states. For any complex value of the central charge $c$, the spectrum of Liouville theory is
$\mathcal{S} = \int_{\frac{c-1}{24}}^{\frac{c-1}{24}+\infty} d\Delta\ \mathcal{V}_\Delta \otimes \bar{\mathcal{V}}_\Delta\ ,$