The bogus “interpretations” of quantum mechanics

I’ve not written on this blog for a long time. A talk in Mouans-Sartoux yesterday prompted me to write this rant about what I will (demonstrably) call bogus interpretations of quantum mechanics. Specifically the “dead and alive cat” myth.

Schrödinger’s cat

One of the most iconic thought experiments used to explain quantum mechanics is called Schrödinger’s cat. And it is usually illustrated the way Wikipedia illustrates it, with a superposition of cats, one dead and one alive:


The article of Wikipedia on the topic is quite clear that the cat may be simultaneously both alive and dead (emphasis mine):

The scenario presents a cat that may be simultaneously both alive and dead,[2][3][4][5][6][7][8] a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur.

In other words, in this way of presenting the experiment, the entangled state of the cat is ontological. It is reality. In that interpretation, the cat is both alive and dead before you open the box.

This is wrong. And I can prove it.

Schrödinger’s cat experiment doesn’t change if the box is made of glass

I can’t possibly be the first person to notice that Schrödinger’s cat experiment does not change a bit if the box in which the cat resides is made of glass.

Let me illustrate. Let’s say that the radioactive particle killing the cat has a half-life of one hour. In other words, in one hour, half of the particles disintegrate, the other half does not.

Let’s start by doing the original experiment, with a sealed metal box. After one hour, we don’t know if the cat is dead. It has a 50% chance of being dead, 50% chance of being alive. This is the now famous entangled state of the cat, the cat being “simultaneously both alive and dead”. When we open the box, the traditional phraseology is that the wave function “collapses” and we have a cat that is either dead or alive.

But if we instead use a glass box, we can then observe the cat along the way. We see a dead cat, or a live cat, never an entangled state. Yet the outcome of the experiment is exactly the same. After one hour, we have 50% chances of the cat being dead, and 50% of chances of the cat being alive.

If you don’t trust me, simply imagine that you have 1000 boxes with a cat inside. After one hour, you will have roughly 500 dead cats, and 500 cats that are still alive. Yet you can observe any cat at any time in this experiment, and I am pretty positive that it will never be a “cat cloud”, a bizarro superposition of a live cat and a dead one. The “simultaneously both alive and dead” cat is a myth.

Quantum mechanics is what physics become when you build it on statistics

What this tells us is that quantum mechanics does not describe what is. It describes what we know. Since you don’t know when individual particles will disintegrate, you cannot predict ahead of time which cats will be alive, which ones will be dead. What you can predict however is the statistical distribution.

And that’s what quantum mechanics does. It helps us rephrase all of physics with statistical distributions. It is a better way to model a world where everything is not as predictable as the trajectory of planets, but where we can still observe and count events.

The collapse of the wave function is nothing mysterious. It is simply the way our knowledge evolves, the way statistical distributions change as we perform experiments and get results. Before you open the box, you have 50% chances of a dead cat, and 50% of a live cat. That’s the “state” not of the universe, but of your knowledge. After you open the box, you have either a dead cat, or a live cat, and your knowledge of the world has “collapsed” onto one of these two statistical distributions.

There is a large number of widespread quantum myths

Presenting quantum mechanics as mysterious, even bizarre, is appealing since it makes the story interesting to tell. It attracts attention. And it also puts physicists who understand these things above mere mortals who can’t.

But the result is the multiplication of widespread quantum myths. Like the idea that quantum mechanics only applies at a small scale (emphasis mine):

Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics.

Another example is the question “why is the wave function complex?” Clearly, this seem problematic to many. But if you see quantum mechanics as a statistical description of what we know, the problem goes away.

La SNCF en flagrant délit d’IP-tracking

La SNCF augmente son prix de 41% en deux minutes

La SNCF augmente son prix de 41% en deux minutes

La SNCF affirme ne pas pratiquer l’IP tracking, J’ai du mal à y croire.

Il y a quelques minutes, ma femme va sur le site Voyages SNCF, et demande un billet Paris-Antibes. Prix du billet: 80€. “Attention, dernières places à ce prix”, bien sûr. Mais à un moment, elle fait une erreur, et décide de refaire une recherche sur le même site. Le même billet passe soudainement à 113€.

Je fais un essai depuis un autre navigateur, puis depuis une autre machine dans la même maison (donc même adresse IP depuis l’extérieur). Le billet reste coincé à 113€.

Mais, histoire de vérifier si les billets à 80€ ont vraiment été épuisés (la théorie du blog de la SNCF ci-dessus), je décide de passer par mon smartphone en 3G. Du coup, forcément, changement d’adresse IP. Et là, surprise (pas vraiment, en fait), je retrouve le billet à 80€. Que j’achète.

Le billet acheté: 80€ seulement !

Le billet acheté: 80€

Alor, si la SNCF ne fait pas d’IP tracking, pourquoi ce que je viens de décrire se passe à chaque fois? Ce phénomène ne peut pas s’expliquer par l’épuisement des billets à un certain palier de tarif; parce que les prix affichés sur un même ordinateur dépendent de l’IP utilisée !

Paul Graham recommends doing things that don’t scale

As usual, Paul Graham writes an interesting piece about startups. He recommends doing things that don’t scale. Thinking like a big company is a sure way to fail. It’s a reassuring piece for the startup creator that I am, because at Taodyne, we are indeed in this phase where you do everything yourself and you’d need 48 hours a day to do the basics. Good to know that the solution to this problem is to keep working.

Connect this to the survivor bias. This is a very serious cognitive bias, which makes us look only at the survivors, at the planes who return from combat, at the successful entrepreneurs. Because we don’t look at the dead startups or planes that were shot down, we build our statistics on a biased sample. As a result, we make incorrect assumptions. For example, if the planes that return have mostly been shot in the tail and wings, you might deduce that this is where planes are being shot at, so that’s the parts you need to protect, when in reality what this proves is that these are the parts that don’t prevent a plane from returning when shot. Very useful.

Last interesting link of the day is the discussion about bullying on the Linux Kernel Mailing List (LKML). Sarah Sharp, a female Intel engineer, stands up to Linus Torvalds and asks him to stop verbal abuse. It’s an interesting conflict between very smart people. To me, there’s a lot of cultural difference at play here (one of the main topics of Grenouille Bouillie). For example, I learned from Torvalds what Management by Perkele means. On one side, it’s legitimate for Sarah to explain that she is offended by Linus’ behavior. On the other hand, it’s legitimate for Linus to keep doing what works.

Sarah reminds me of a very good friend of mine and former colleague, Karen Noel, a very sharp engineer who joined me on the HPVM project and taught me everything I forgot about VMS. Like Sarah, Karen was willing to stand up her ground while remaining very polite.

Everything is broken and no one cares

Everything is broken and no one cares

This post from Dear Apple is just so true, and so clearly on topic for Grenouille Bouillie!

Have we reached the point in complexity where we can’t make good quality products anymore? Or is that some kind of strategic choice?

The original post is mostly about Apple products, but the same is true with Linux, with Android, with Windows.

Here is my own list of additional bugs, focusing on those that can easily be reproduced:

  1. Open a file named X in any of the new Apple applications, those without Save As. Open another file named Y. Save Y as X. Beachball. For every application. Worse yet, since applications often remember which windows were open, you get the beachball again when you reopen the application. It takes another force quit for the application to (fortunately) offer to not reopen the windows.
  2. A relatively well known one now: Type F i l e : / / / in practically any OSX application. Without the spaces. Hang or assert depending on your luck.
  3. Use a stereoscopic application like Tao Presentations ( Activate stereoscopy. Switch spaces or unplug an external monitor. Kernel panic or hang to be expected. Go tell to your customers that the kernel panic is Apple’s fault, not ours…
  4. If you backup over the network, set your computer to sleep after say 1 hour while on power. Change your disk enough that the backup takes more than one hour. Backup disk will come up as corrupt after a couple of days, and OSX will suggest you start a new one (and the cycle will repeat).
  5. Use the “Share” button. It takes forever to show up the window (like 2-3 seconds in general on my 2.6GHz quad-core i7 with 8GB of RAM). Since what I type generally begins with an uppercase letter, I usually prepare myself by having the finger on the shift key. But to that stupid animation framework, “shift” means “slow animation down so that Steve can demo it”. Steve is dead, but the “shift” behavior is still there.

I’ll keep updating this list as more come to mind. Add your own favorite bugs in the comments.

First update (Feb 13, 2013):

  1. Safari often fails to refresh various portions of the screen. Visible in particular when used in combination with Redmine. This used to be very annoying, but it has gotten much better in more recent updates of Safari.
  2. iTunes 11 no longer has Coverflow. It was a neat way to navigate in your music, which wasn’t even the default, why remove it?
  3. Valgrind on OSX 10.8 is completely broken. I have no idea what’s wrong, but it’s a pretty useful tool for developers, and Apple has nothing in its own development tools that is even remotely close.
  4. “Detect displays” is gone, both from the Monitors control panel and from the Monitors menu icon. Combine that with the fact that OSX 10.8, unlike its predecessors, sometimes totally fails to detect that you unplug a monitor. And you find yourself with windows stuck on a screen that is no longer there…
  5. That little Monitor menu icon used to be quite handy, e.g. to select the right resolution when connecting to an external projector for the first time. Now, it’s entirely useless. It only offers mirroring, fails to show up 90% of the time when there is a possibility to do mirroring, shows up when mirroring is impossible (e.g. after you disconnected the projector). It used to be working and useful, it’s now broken and useless. What’s not to love?
  6. Contacts used to have a way for me to format phone numbers the way I like. That’s gone. Now I have to accept the (broken) way it formats all phone numbers for me.
  7. I used to be able to sync between iPhone and Contacts relatively reliably. Now, if there’s a way to remove a phone number, I’ve not found it. Old numbers I removed keep reappearing at the next sync, ensuring that I never know which of the 2, 3 or 4 phone numbers I have is the not dead one.
  8. Still in Contacts, putting Facebook e-mail addresses as the first choice for my contacts? No thanks, it was heinous enough that Facebook replaced all genuine email addresses with aliases. But having that as the first one that pops up is really annoying.
  9. Now fixed, but in the early 10.8, connecting a wired network when I also had Wifi on the same network would not give me higher speed. It would just drop all network connectivity.

Updated February 28th after restoring a machine following a serious problem:

  1. Time machine restores are only good if your target disk is at least as big. But with Apple’s recent move to SSD, this may no longer be affordable to you. In my case, I’d like to squeeze 1TB of data into 512G. Time machine does not give me the level of fine-grained control I’d need to restore what I really need. So I need to try and do it manually, which is a real pain.
  2. Calendar sync is a real mess. Restoring calendars from a backup is worse.
  3. Spaces? Where are my good old spaces? Why is it I had spaces on the original machine, no longer have them, and find myself unable to say “I want 6 spaces” or to setup keyboard shortcuts for them as they used to be.

When Google oversteps its authority

Recently, a user of Tao Presentations informed us that Google Chrome displayed a dire warning after he downloaded our software: “Tao Presentations may be malicious software”. Uh oh, for the average Joe, that’s a big no-no.

Google locks out “unapproved” programs

It’s not just us. Recently, I tried to download some of the amazing demos created by Iñigo Quilez. Same thing. Seriously, a 4K exe that manages to display a complete mountain? And Google Chrome would have me believe that there’s room in there for “malicious software”? Get real.

Now, it took me quite a while to find a solution to this problem. Apparently, you just need to record your site in Google’s Webmaster tools, and after scanning your site and ensuring (I assume) that there’s no known virus signature in the files, things should improve.

I still find this really annoying that a browser vendor would, by default, tag unknown files as “malicious”. Who are they to make this judgment call?

Why didn’t Google implement a real solution?

Shouldn’t they instead have something a little more sophisticated, that actually detects malicious signatures? You know, like a real anti-virus? Don’t tell me that Google doesn’t have smart enough engineers to write an in-browser anti-virus that doesn’t completely suck.

Nah, instead they went the easy route: anything that we don’t know is malicious. And we tell your users so.

I used to be a big fan of Chrome. Not anymore. Because of this single issue. I think this demonstrate an incredibly stupid arrogance and lack of technical diligence on Google’s part.

Google overstepped its authority and took advantage of their weight. Let’s not get used to it.

Moi Président de PME

Quel “président” j’aimerais être?

Un président de PME qui, d’abord, respecte la France, qui l’aime. Je suis le président d’une petite société, je ne peux être que président de pratiquement rien, chef de rien, mais en définitive responsable de tout.

Moi, président de PME, je ne suis même pas le chef d’une minorité. Je n’ai pas le temps de recevoir qui que ce soit parce que je travaille soir et week-ends.

Moi, président de PME, j’ai à traiter avec des investisseurs, pas à polémiquer de savoir si on les appelle associés ou collaborateurs.

Moi, président de PME, je participe à toutes sortes de collectes de fond parce que que je n’ai pas l’option du déficit budgétaire.

Moi, président de PME, je fais fonctionner la boîte de façon indépendante, mais j’ai des compte à rendre si j’agis contre l’avis de mon “conseil d’administration” (ou ce qui en tient lieu dans une SAS).

Moi, président de PME, je n’ai pas la prétention de nommer des directeurs, je sais très bien que c’est par leur indépendance d’esprit et leur initiative qu’ils ont mérité ce titre

Moi, président de PME, je fais en sorte que mon comportement soit à chaque instant exemplaire, tout en ayant une conscience plus aigue que jamais de mes propres limites.

Moi, président de PME, ce n’est pas de gaité de coeur que j’ai un statut très peu protégé, sachant très bien que si mes actions venaient à être contestées, aucun magistrat n’hésiterait jamais à me convoquer.

Moi, président de PME, j’ai constitué une équipe paritaire, avec autant de femmes que d’hommes dans la mesure où on peut le faire dans une équipe de cinq. Et alors?

Moi, président de PME, je suis soumis tout comme mes investisseurs à un code de déontologie qui interdit tout conflit d’intérêts. Là encore, et alors?

Moi, président de PME, je constate que mes associés ne cumulent rien, sinon les heures de travail mal payées, car on peut considérer qu’à partir de 70h par semaine, on se consacre plus que pleinement à sa tâche.

Moi, président de PME, j’aimerais bien voir un peu de décentralisation, j’aimerais bien qu’on donne aux forces vives locales que sont les PMEs un nouveau souffle, qu’on tire parti de leurs compétences, qu’on leur accorde un peu de liberté.

Moi, président de PME, j’aimerais bien grossir assez pour avoir des partenaires sociaux ou consacrer du temps aux associations professionnelles. Je préférerais quelques discussions régulières à des lois imposées sans négociation.

Moi, président de PME, je me contenterais bien d’un petit débat. On a évoqué la taxation du capital, et il est légitime qu’il puisse y avoir sur ces questions là un débat citoyen.

Moi, président de PME, je suis soumis à la proportionnelle face à mes actionnaires, et ce n’est pas en 2017, c’est dès maintenant que l’ensemble de leurs sensibilités est représentée.

Moi, président de PME, je suis la tête dans le guidon, avec toute la hauteur de vue qui va avec. J’aimerais bien fixer de grandes orientations, de grandes impulsions, mais en même temps, je dois m’occuper de tout et je dois avoir toujours le souci de la proximité avec les clients.

J’aurais bien aimé une vie un peu plus normale, mais rien n’est normal quand on est président de PME. Etre président, c’est pas si facile. Notre monde traverse une crise majeure, en tous cas la France. Mais on peut encore réussir à se fâcher avec l’Europe. On peut encore créer plein de conflits en se montant les uns contre les autres ou en se disputant sur l’environnement Bien sûr qu’un président doit avoir une réponse toute prête qui prenne de haut ses sujets: “je n’aime pas les riches“, ça suffit largement à montrer qu’on est proche du peuple, qu’on est capable de comprendre toute la complexité de réalité économique et sociale en France.

Cela dit, moi, président de PME, j’aimerais bien qu’on laisse nos investisseurs tranquilles. Ca serait déjà pas mal comme changement tout de suite.

Et si vous ne comprenez pas pourquoi je dis ça:

(Mis à jour pour utiliser le terme de PME, plus général que SAS)