Wednesday, 30 July 2014

Letter to a European Research Council referee

Dear motherfuc referee,

Thanks very much for your insightful comments. Below I discuss some of your deep observations.

Ground-breaking nature and potential impact of the research project: 
Multidisciplinary proposal. The physics part is rather weak in terms of possible achievements and originality.

I see that you managed to summarize your opinion about my five-page project synopsis in just one line. You must be exhausted. Other referees would have copied one or two sentences from the abstract just to give the impression that they actually read the proposal. But you’re right: why pretend? Actually, why did you bother writing anything at all? Next time, send a disgusted emoticon, “unfollow” my proposal, or just type: “GRAAAAAHHH!” in order to express your “pondered opinion” about my work.

The I-spit-on-your-ERC-proposal emoticon, soon in 90% of all ERC evaluation reports.
Yes, my friend, mine is a multidisciplinary proposal. The goal is to develop a computational framework to reason about infinity in quantum mechanics. I’m sure that every day you evaluate hundreds (or millions!) of proposals just like mine, and that’s why you didn’t regard it as original as, say, entanglement detection or quantum simulations with an ion trap. It is certainly not as original as texting an ERC referee report from your iPhone while driving over postdocs in the park, as you plainly do during working hours.

You write that"the physics part is rather weak in terms of possible achievements". I see. For you, demonstrating experimentally that the world is infinite-dimensional is a weak achievement. Let me ask you: what qualifies as a strong achievement? Building a time machine? Attaining immortality? Typing a ten-line report with your penis?

Principal Investigator
To what extent has the PI demonstrated the ability to propose and conduct groundbreaking research? Very good.
To what extent does the PI provide evidence of creative independent thinking? Very good.
To what extent have the achievements of the PI typically gone beyond the state of the art? Very good.

Comments (Optional for reviewers)
Average past performance and impact.

According to the applicant's guide, “very good” is just one grade above being declared “not competent”. Geez, pal, thanks a lot for not recommending the ERC to lock me in a mental institution!

I find your scores very surprising, though, because I would have thought that my work on the characterization of quantum correlations was groundbreaking at the t... but, oh, my God! I forgot that Toni Acín, my PhD advisor, also signed that paper!!! It is obvious that Toni proposed the project, conducted the research and wrote the paper single-handedly; then he put me as first author because I sodomized him brought him coffee. So you’re right, that paper doesn’t prove anything.

How about the rest of the achievements that I summarized in the Achievements section* of my CV? There you can find many instances of creative, independent work, and… ah, you didn’t read it.

My fault: I should have placed a picture of a crucified postdoc in order to get your attention. Besides, if my achievements were so advanced, surely one of them would have acquired self-consciousness, escaped from the CV and tried to contact you. Nothing like that happened, unless at that precise moment you were too busy sculpting jars with postdoc skulls, so that you can drink their blood and live forever.

*Judging from the referee reports, the Achievements Section is a goblin-like mythological creature that lives at the end of my CV and no ERC referee can see.

You might think that I’m being a bit harsh on you, my dear referee. But you must understand. Right after screwing someone’s scientific career with pearls like: “average past performance and impact”, you should at least have the decency to discuss the applicant’s past achievements and argue why they are “average”. Could it be, my dear referee, that you just went through my publications, saw that they didn't have many citations and concluded that my work was “average”?

Then answer this, you vile amoeba! How many citations did John Bell's 1964 paper have for the first ten years? How many citations did Werner’s paper on local entangled states gather between 1989 and 1995? How many citations did the BB84 paper have in 1993? Do you, in your stupid, simplified and self-complacent view of the world, believe that all these papers were lame until year 2000, when they –all of a sudden- became breakthroughs?

“Oh!”, you could say (though in your case I bet it’d sound more like: “HEEHAW!”), “but nowadays quantum information is a well established field! What is your excuse to get so few references?”.

It is ridiculous to put all QI scientists in the same lot: if you don’t know this, you shouldn’t be a referee for the ERC. QI has different subfields, and average citation numbers vary widely between them. Foundations-related research does not get many citations because the community is small and fragmented. It’s not like in quantum computer science, where every year the whole community works on essentially five different problems and any progress whatsoever gets highly cited.

“But even in nonlocality some people get a lot of citations. Why can’t you be like them?”

As you perfectly know, nowadays papers are rarely cited to acknowledge inspiration or to invoke mathematical results: they mainly get referenced at the introduction of other papers, whose authors want to convince journal editors that “our topic is very interesting, because all these other people have worked on vaguely related stuff”. So, in order to be cited at an intro, your result must fit perfectly in a well-established paradigm and be twitter-like, that is, summarizable in a few words which, if possible, should rhyme and make a catchy tune (like: “nana nana nana nanaaa... discord!”). Everything else, like novel topics or deep results, is excluded.

For most of my career, I’ve been trying to conduct original research. Now I’m paying the price. Shall I get specific? I love this paper, but, for my life, I cannot imagine anyone citing it in a near future. My paper on the characterization of quantum nonlocality (which, I admit, is not extremely original) hardly had any citations three years after its publication. And my 2009 paper on macroscopic locality started getting citations last year. Why? Because people (finally!) acknowledged that it should be cited at intros along with the information causality paper.

“Wait a moment. Not all original works take time to find recognition. Special relativity was successful from the very beginning!”

Exactly: special relativity was not original, even Einstein admitted it. This may surprise you, after how much this word has been devaluated by funding agencies, but not all important discoveries need be original. Think of the finite quantum de Finetti theorem, or the non-additivity of the classical capacity! Do you want more examples? Antiretroviral therapy, global warming, the standard model of particle physics.

Conclusion (this is for you, rats; the referee must have stopped reading a while ago)

ERC is very much like any other grant: it is targeted to individuals with a strong citation record that hints extreme popularity, and to projects which, no matter the outcome, contribute to enhance the candidate’s publication statistics.

Contrarily to institutional propaganda, ERC is not targeted to independent, creative scientists with high risk/high gain, original projects. Even to the average EU bureau-cretin it should be evident that you cannot estimate independence and creativity if you refuse to read the abstract of a single paper of the applicant. As for proposal reviewing, having referees like the android above evaluating originality is like having Alanis Morissette evaluating irony. So let's throw them all to a volcano and start the selection process again. This time we'll ask them to write a poem before trusting their views on whatever the hell they believe creativity is.

Let me finish with this prophecy (or curse!): ERC-funded theoretical projects will never be high-risk. The reason? Because, like with any other grant, you’re expected to specify… -gasp- … every single step … aargh…  of your research program… aarrrghh … in the BLOODY 5-PAGE SYNOPSIIIIIIIIIIIS!! AAAARRRRGHHHH!!! HULK VERY ANGRY!! WICKED ROBO-REFEREE HURT HULK!!! HULK SMASH AND BASH!!! GRRROOOAAAARRRR!!!

Yours faithfully,

Schroedinger’s rat

Still here?

The post is finished. Turn off the computer and go to the gym. You could do with some workout!

Or you could call your mother. When was the last time you talked to her?

I mean REALLY talk.

Seriously? That long!? Shame on you!

OK, OK. Here goes a...

Bonus epilogue!!

When I was a teenage-mutant-ninja-rat, my literature teacher surprised us one morning by announcing an advertising contest. The students had to pretend that they lived in the 17th century and design a poster announcing the second part of Don Quixote. The most original and creative posters would be exhibited!!

My classmates and I were puzzled: the teacher was a control freak, and giving us artistic freedom was completely out of character. Nevertheless, I gave it my best shot: I wrote a humorous pamphlet about Cervantes’ second part of Quixote parodying a “Hello!” magazine front cover.

Not only I didn’t win the contest, but got severely reprimanded by my teacher. She wrote over my poster: “WHAT THE HELL IS THIS?” and gave me a bad mark.

Later that day, a classmate asked me why I looked so grumpy. I said: “I spent a whole evening coming up with ingenious ideas for that homework, and the teacher doesn’t even think it’s original!”.

My friend smiled. “Miguel”, she said, “have a look at the winning posters”.

I did. The posters were exhibited in the class’ announcing board. There they were: the six of them in all their glory.

One showed a picture of Don Quixote, trotting away on his horse. The poster read: “Reject imitations! Buy yourself a copy of the actual second part of Don Quixote!”. The author of the poster was making reference to Fernández de Avellaneda’s apocryphal sequel of the adventures of Don Quixote.

Now, I don’t need to describe you the rest of the winning posters.

Because the other five said exactly the same.

Friday, 22 November 2013

Do not work in Quantum Foundations under any circumstances. Or do so, what the hell.

Hi rats,

Very often, people come and tell me*: “Rat, you are so magnificent! Here you are, a former magician-actor-tap dancer-model-ninja-vampire-master of the universe-Madonna. How come that someone with your obvious talents and –ehem!- sexy muscular body is wasting his time in foundational research? (blink, blink)”.

*Approximate reconstruction.

The answer is complicated. I think I’m not surprising anyone when I say that nowadays Foundations of Physics raises the same expectations as a new star trek movie. For most, Foundations is synonym of mediocre results, low-level mathematics and endless pedantic discussions. And it is true: most works in Foundations (and even whole conferences!) are just like that. One has to dig very, very deep to find that precious gem that makes everything worth it.

In this post, I will try to summarize the good and bad aspects of the field. That way, independently of what you choose to make of your scientific careers, you'll know what you can expect, or what you'll be missing.

Let's start with the cons: working in Foundations sucks when…

1) … someone proposes a lame semi-classical model for photon polarization that actually reduces to the definition of quantum separability when one tries to make physical sense of it. However, since the author holds a Nobel Prize for completely unrelated research, the “discovery” soon becomes a popular topic in Foundations that no amount of logical arguments can kill. Bravo!

A different take on this story, advocated in this note, is that the photon model may be, in fact, scientifically sound. When the laureate defines a model inconsistent with the notion that post-selection is a type of preparation, he’s not making a gross mistake: he’s proving his creative genius by "freeing himself" from this traditionally held assumption*. And when the laureate violently bumps his head against the floor, he’s not stumbling and falling: he’s estimating the density of concrete in public pavements.

*Indeed, how could I be so blind!? Why didn’t I consider the possibility that, after measuring a photon, the universe disappears, or all other photons turn into Toblerone bars?

2) … for the third time, the John Stewart Bell Prize, which is awarded “for significant contributions first published in the [last] 6 years” and “is not intended as a "lifetime achievement" award” (check the rules), goes to senior group leaders.

Dear committee members: Adán Cabello will renege on contextuality before you award the prize to a mere postdoc, so stop giving false hopes to junior researchers. Be honest, remove the six-year requirement from the description of the Prize and give it to Tsirelson. God knows that, if someone deserves the John Stewart Bell Prize, that is Boris Tsirelson, the man who invented quantum Bell inequalities. Like Bell, he had a deep vision that translated into breakthrough results. And, like Bell, his work was largely ignored by the Physics community at the time.

Rats, I say we owe Boris Tsirelson big time: a prize for Tsirelson, now!!

The John Stewart Bell Prize committee, deciding the fate of a postdoc nominee.

3) … people from serious* fields advance a foundational topic by an epsilon (OK, two epsilons), get their results published in Nature and everybody wets their pants. Meanwhile, all other relevant contributions rot.

*Here by “serious” I mean “socially acclaimed”. If you believe that quantum computer science is objectively serious, stop random pedestrians on the street and try to explain them why quantum complexity classes are much more important than, say, epistemic models. If they try to escape, hit them on the head with your gun**.

**You don’t have a gun!? Then, how do you get people to cite your work at introductions and review papers?

4) … two authors publish three times essentially the same result (and I'm not counting the review!).

Why stop there? From this blog I want to propose Colbeck and Renner new ideas to spread their message:
  • “Quantum mechanics is complete”, the coloring book (it’s already colored), and “Quantum mechanics is complete”, the jigsaw puzzle (one piece may be missing).
  • “nIv'e', yu'egh Qap, tugh Qo' (the wave function exists, soon you won’t)”, the Klingon Opera.
  • “Who moved my local part?”, the best-selling book that has helped millions find their true nonlocal selves and now it can help you, too!
  • “The Texas chain Bell inequality”, the independent motion picture directed by Lars von Trier, with Nicole Kidman as the statistical distance and Philip Seymour Hoffman as the random variable Z. All the characters are trapped between the pages of a prestigious journal!
5) … people resort to obscure foundational problems to motivate an elementary experiment, whose results are published in Science.

Seriously, does it make sense to conduct Wheeler’s delayed-choice experiment in the 21st century? In the same line, why not measure the speed of aether, or the weight of a soul?

Experimental demonstration that the pagan god Mawu does not manifest when the pentacle is open. Did Mawu know in advance that we were going to open the pentacle? To appear in Nature Communications.

All right, enough cons for today.

Let's hear the pros: working in Foundations rocks because…

1) … contrary to absurd claims, there IS a measurement problem*.

*The problem is to explain why measurements return a single outcome, not why we don’t see macroscopic superpositions. Decoherence advocates, cut the crap: you’re not advancing the problem at all!

2) … problems are interesting by themselves. Not because you can relate them to algebraic topology, not because solving them will prove everyone how clever you are* and not because Terence Tao has worked on the topic before.

*Electroshock, please.

3) … there is room for imagination.

OK, rats, this has been all. I hope that this post has inspired you to do something productive, like insulting me in the comments meditating on deep foundational issues. It has certainly inspired me to try to get invited to QCRYPT next year by republishing my 2006 hit on Optimality of Gaussian Attacks in CVQKD. What do you think, rats? Shall I submit it to PRL? Or should I try Nature Communications this time?

Yours truly,

Schroedinger’s Rat

Monday, 8 July 2013

The PNAS hotel

The Rat, 2013

Hi rats,

This post is about high impact factor journals, i.e., those publications where you have to convince an entity called “editor” that your article is “cool” and will “appeal to a wide audience” before having a chance to get it reviewed by someone who's not an ignorant. Most of you won’t pass this first filter. That is, unless an individual whom I've never seen in any nonlocality workshop claims in Nature News that your result is “the most important general theorem relating to the foundations of quantum mechanics since Bell’s theorem”

Hence I will focus my rant on this aspect, the editor stage, because I find astounding that editors of professional scientific journals regularly reject submissions on completely unscientific grounds. Whenever I get a good original result and am able to summarize it in four pages, I know that I will probably get it published in PRL. I wished I could say that whenever I get an exceptional result it will most likely be published in Science, Nature or Nature Physics. If that were the case, I wouldn’t be writing this post.

What’s wrong with high impact factor journals? Is it true that under their human masks Nature editors are a reptilian species sent to destroy Earthen civilization by featuring articles like this? Desperate for answers, I went to the Bristol University Mensa and asked researchers on this matter. I found that their opinions fall into three categories:

a) The Conformist: “Yes, sure, the system is far from perfect, but that’s all there is. So stop whining and send those families to the reeducation cam- sorry, wrong forum.”

b) The Outraged Conformist: “Those journals are a shame and we should boycott them all. But first let me submit my new paper “If quantum mechanics were more nonlocal, an avian compass would violate the second law of thermodynamics in the Canary Islands””.

c) The Understanding: “You have to put yourself in their shoes… these editors receive a lot of papers every week, they have to come up with a system to release that load. And the simplest way is to reject all papers written by junior scientists. Now I have to leave you, that man with the scars over there says that he wants my “fucking” shirt. Poor soul, he must have suffered so much. I will offer him my money, my house and my first-born baby”.

Between the lines, one can read some skepticism about the transparency of editorial decisions in high impact factor journals. Let us dig into this:

In his book “Reason strangled”, chemist and journalist Carlos Elías argues that Nature’s top-one priority is to maintain its impact factor; that allows the journal to set the prize of the publication. Problem is, Nature’s impact factor is already so high that a lot of effort must go just into not letting it drop. Hence Nature editors have to make sure that each article will be highly cited. Articles signed by famous scientists are read more, and, consequently, have more citations. Likewise with prestigious affiliations, fancy titles, articles already mentioned in the press. Elías writes about Nature, but I guess that his conclusions apply to other high impact factor journals as well.

It follows that the paper “Full algorithmic characterization of LOCC quantum operations”, by John Unknown, from Mac&Cheese Community College, will have a cold reception. On the other hand, the article “Quantum mechanics is extra-spicy”, signed by Stephen Hawking, Edward Witten and David Bowie, and featured on TV by Beakman and the Myth Busters, will make the same Nature editors twist and shout. Don’t forget that we’re speaking of a journal that in 1996 published an article about the analgesic effects of myrrh. Because it was a relevant result in the field? No! Because it was Christmas time!

The need to increase the journal’s impact factor explains many things, but does not answer all my questions. How come that exactly the same document is called “Supplementary Material” in Science, “Supplementary Information” in Nature, “Supplemental Information” in PNAS and “Supplemental Material” in PRL*? Do they want to drive us crazy? Why can’t PNAS editors read a reference where the author’s initials are - sacrilege! - before the family name? Are they aware of the amount of time that it takes to submit a paper to this journal, only to see it rejected the next week? If I conduct the research, write a referee list and prepare the paper in their damned unique format, what do the so-called editors do? I mean, besides checking my affiliation and h-index and replying “we receive more papers than we can publish, so we have to select those that will be of the greatest interest to a wide audience”. Do they understand how that sentence feels like when the next day they publish whatever crap with the words “spooky” and “quantum” in the abstract? Come to think of it, why do high impact factor journals have an impact factor at all? Shouldn’t they be in the same lot as other popular science magazines, like Scientific American, New Scientist and Physical Review A**?

*I know, PRL is not a high impact factor journal. But it’s where most good Physics papers end up after being rejected by the first three, they should make the transition easier!

**OK, here I went too far.


When I was a young postdoc, within two months, two different groups proposed two physical principles to limit quantum nonlocality. One group included important figures in QI who had previously published in Nature. Even unpublished, their work was soon echoed in the press (what? You never heard of information causality? How long did you say you stayed in that coma?). The other group was composed by a relatively unknown postdoc (me) and a second-year PhD student.

My collaborator and I knew that nothing short of building a time machine would have allowed us to pass the editors of a high impact factor journal. However, when we heard that the first group had managed to get their paper accepted in Nature, we thought: “now we have them by the balls”.

On one hand, Nature editors could not claim that our work wasn’t of general interest, because the same considerations would apply to information causality. On the other hand, they couldn’t argue that our work didn’t represent a significant advance, because it advanced the field as much as information causality did. In sum, the two main arguments for rejection in Nature didn’t apply. Cowabunga!

Of course, we were assuming that Nature editors can feel human emotions, like shame. Our article never went to referees. Guess why? Because “it was not of general interest and did not represent a significant advance”. A prior submission to Nature Physics had had exactly the same response.

Outraged, I wrote to Nature’s Editor-in-Chief, explaining my case*. My letter ended with some recommendations for the journal:


I therefore suggest you to change the contents of the Nature webpage concerning how to get published. It will not be so glamorous, but at least it will be honest. It could start by:

1. It is completely admissible to exaggerate one’s work to the point that no future research can compete with your so-claimed results.

2. If you are not a key figure in your field, stop reading. We are currently working on a webpage that can only be accessed by scientific celebrities, but, meanwhile, we would appreciate your cooperation if… wait a moment! Why am I wasting time talking to a Nobody? Leave! Now!

3. Oh, it’s you again! Didn’t I tell you to come back when you are famous? Go away, your anonymity smell is making me dizzy… what? How can you become famous? Err… I don’t know… By publishing in Nature?

4. Even if your work is not good enough for Nature, you can still try with Nature Physics. There, an editor with a PhD in experimental ultraviolet LEDs will review your theoretical paper on Foundational Physics and copy-paste his opinion about it. In order to guarantee a polite response, we have removed the exclamation sign from his keyboard.


And so on. That way, people will not get the wrong impression that Nature is a scientific journal, but the nerdy version of “Hello!”.

I think I have already written enough, and I do not want to waste more of your precious time; you must be very busy eating young researchers. But do not worry, this is not a “see you soon”, it is more a “see you never”.

A rat had been born.

Yours truly,

The Rat

Wednesday, 20 March 2013

Research lines that lead nowhere (II) to publishing in Nature: unnecessary experiments

Hi rats,

When I was a young muroid, my collaborators and I proved that, for the state estimation of pairs of coherent states of the form \ket{\alpha}\ket{\alpha*}, entangling measurements are more efficient than LOCC measurements, contrary to the case \ket{\alpha}\ket{\alpha}. The result was curious, and I was convinced that we would manage to publish it in a nice journal (at that time, PRA was a nice journal).

Then, something happened. My supervisor told me that he had contacted an experimental group which was willing to prepare pairs of coherent states and perform the optimal LOCC and entangling measurements.

I couldn’t believe my ears. An experimentalist, the superior species, wanted to test our result!! I was joyous and jubilant, because I was not fully convinced by our rigorous mathematical proof. My supervisor and I were so happy indeed, that we held hands and sang and danced together. Then Christopher Robin and Doraemon came with an apple pie, and we all had a nice meal under the shade of the Magic Oak Tree, in Sugarcandyland (Bromley South).

In the real world, however, I was confused and angry. We already knew what was going to happen. What did those experimentalists expect? That quantum mechanics was going to break in an experiment involving two coherent states, a beam splitter and homodyne measurements? That once the setup was complete, the skies would open and a deep voice would say: “thou shall not finish that experiment!”?

Well, the experiment was completed, and, behold, they measured what the theory predicted. Once more, quantum mechanics (and the world!) was saved.

This post is about futile experiments like mine which are perhaps a bit too subtle for an Ig-Nobel prize. You know what experiments I’m talking about: the kind which make you scream “for the glory of Cavendish!!” when you see them featured in the cover of renowned scientific journals. The kind which the theorists involved describe as: “…and then we performed the experiment. I’m sorry”.

Well, I’ve had enough. I won’t stay silent while promising QI theorists and experimentalists waste their talents in meaningless collaborations. Did you know that people in other fields (e.g.: organic chemistry) conduct experiments to actually advance the theory? It’s time to kick some asses.

Before starting my monthly rant, though, let me clarify what this post is not about.

In this post I’m going to discuss six experiments. I won’t criticize the theoretical results underlying these experiments (well, just one), or the technical ability and innovation of the experimentalists who carried them out. What I will argue here is rather the need to perform such experiments. So if I have happened to single out one of your papers and at any time you feel that I’m undermining your work, please come back to this paragraph and re-read it as many times as necessary.

And then be honest: do we really need more experiments like…?

1) Experimental demonstration of 2, 3, 5, 6, 8-photon entanglement.

Contrary to popular claims, we don’t have a use for generic entanglement, so most of these results have no practical application (what is the usefulness of an 8-party GHZ state!?). One could argue that entangling a vast number of particles may be theoretically impossible due to collapse theories, etc., and that it is interesting to see how far we can go. Even so, photons are a very bad candidate to look for violations of quantum mechanics; massive particles seem to me a better choice.

Where does this obsession to entangle photons come from? How many photons will have to get entangled before the topic dies out? For Christ’s sake, somebody write a paper showing how to entangle n+1 photons from n entangled photons, and stop this madness for good!

2) Experimental estimation of the dimension of classical and quantum systems.

The story begins an interesting theoretical study of the correlations generated by classical and quantum systems of dimension d in prepare-and-measure scenarios, followed by a complicated optics experiment where the authors certify dimension four. Unfortunately, certifying dimension four is not that difficult: I can do it with my balls an abacus, or a mango and a watermelon. And there's more! I can remember 9-digit phone numbers, so I can certify dimension 10^9. Don’t study quantum optics, study me!!*

*This sentence won the prestigious award Worst Pick-Up Line Ever 2004.

3) Environment-induced Sudden Death of Entanglement

This project was born dead. The authors present an experimental demonstration of entanglement sudden death for a two-qubit state subject to amplitude decay and phase damping channels. In case you’re not familiar with ESD, here’s the theory of the paper in three pictures:
The ellipsoid represents the set of separable states; the extremes of the stick, the initial and the final quantum state after repeated iteration of the quantum channel. (a) If the channel converges to a point in the boundary of the set of separable states, for certain initial states, the system will enter the ellipsoid in finite time (ESD). (b) For some others, it won't. (c) However, if the map converges to a point in the interior of the set, you will always observe ESD.
Fascinating. Let us now discuss the need for an experiment. The authors claim that “photons are a useful experimental tool for demonstrating [ESD] and, more generally, for investigating quantum channels like [the amplitude decay channel], as the decoherence mechanisms can be implemented in a controlled manner”.

Of course, this is all bullshit, because these two channels are defined mathematically, so one can perform a simple analytical study of the properties of the states which undergo such transformations (which the authors actually do). Implementing these channels in an optical scenario is not going to add any insight, just experimental errors. And as for ESD verification, an in-depth pub study of the different ways to touch an olive with a toothpick is equally revealing and much tastier.

4) Violation of Bell’s inequality in Josephson phase qubits

The CHSH inequality (there are so many Bell inequalities, why does everyone choose the same?) has been violated with photons, ions and cold atoms. So what? Violating CHSH with two yoghourt cans tied with a string is hardly surprising if you allow for locality or detection loopholes. The actual challenge is to violate local realism, i.e., to implement a loophole-free Bell test. If you’re an experimentalist with a genuine interest in nonlocality, don’t waste your time and ours with more non-conclusive games and go for the real thing once and for all.

And don’t make me speak of contextuality experiments; there the “loophole” turns into Madonna’s vagina.

5) Closed time curves via post-selection: theory and experimental demonstration

Synopsis: the authors come up with a model for quantum time machines, mathematically equivalent to teleportation with post-selection. Then, they decide to make an experiment to “test the predictions of the theory”.

OH-MY-GOD! A time travel experiment!! Our heroes travel back to 1955 in a modified DeLorean and accidentally seduce their own mothers in a thought-provoking adventure of self-discovery*.

*More concretely, the discovery that you’re inclined to practise incest.

Well… no. Rather, they perform a very expensive and time-consuming experiment of quantum teleportation with post-selection. Then they verify that, indeed, quantum teleportation gives the same predictions as their time-machine model, which by definition gives the same predictions as quantum teleportation. The paradox is therefore solved in a self-consistent way, Martin McFly’s right hand reappears and he can finally wank return to 1985.

I strongly recommend the authors to travel back in time and remove the experimental part from their letter. Not for me, or for you, but for the students. Think of them and their bleeding eyes when they read your paper!

6) An experimental test for non-local realism

Here an experiment to violate Leggett’s model of crypto-nonlocality is carried out. This experiment, as well as any other one trying to disprove Leggett’s model, is pointless: if a set of bipartite correlations p(a,b|x,y) is compatible with Leggett’s axioms, then it must correspond to the statistics generated by a two-qubit separable state (see arxiv:1303.5124). This implies that any experiment showing entanglement between two photons is a refutation of Leggett’s model. Since two-photon entanglement has been verified ad nauseam, Gröblacher et al.’s experiment was not necessary. This is a case where the theory was simply not advanced enough to embark on an experiment.

Enough blood for today. You have already seen several examples of unjustifiable waste of tax-payer’s money in pointless experiments. Yet many authors of these papers are respectable figures in QI. What is happening?

When the scientific community acts bizarrely, dig in and you will find an important journal at the bottom of the trash-bin.

Some years ago, an unhealthy paradigm of research in QI was established via journal feedback: the duty of theorists is to develop results which are experimentally testable with current technology, while experimentalists are expected to come up with ways to implement the protocols which the theorists devise.

Play by the rules of the game, and you will get rewarded: if you’re a theorist, you will get published in prestigious journals, like Nature or Science, where theoretical Physics hardly ever appears (and if it appears, it is usually in embarrassing forms). If you’re an experimentalist, you can claim that your technical achievements are actually interesting -read “practical”- for quantum information processing.

The negative side, of course, is that many theorists are limiting their theoretical research to subjects where “experimental investigations” can be carried out straightforwardly. Most worryingly, the paradigm has driven experimentalists to theorist hunting, a recent mass phenomenon that I invite you to contemplate at your next theoretical seminar: hordes of experimentalists, sitting on the back row, breathing anxiously, their claws ready to trap any theoretician who can tell them what the hell to do with their current optical setup. It is precisely this obsession to implement experimentally whatever is fashionable in theoretical circles what leads to surrealistic situations where four different groups report experimental boson sampling in the same week.

These are my final messages:

1) Experimentalists: for many of you, the real motivation is the experimental control of quantum systems. Such is a noble enterprise; be proud of your work and stop forcing QI applications into your papers.

2) Theorists: not every theoretical discovery must be complemented with an experiment. E.g.: it is possible to control where soldier crabs walk by projecting them predator shadows; hence, in theory, one can build a computer using swarms of crabs rather than electric currents. However, no serious researcher would attempt to perpetrate such a stupi-. Oh, no.

Yours truly,

The Rat