prof-dr-ir

> The fix for this is easy: pull people over.

Or, as is currently being tested in many European countries, cameras above the road that automatically detect drivers on their phones.

But I am not optimistic about that taking off in the US, where even speed cameras are a rarity (although I do not really know why).

I downloaded Marta and it looks and feels absolutely amazing.

But then I noticed that it is not open source, the sole developer has been on a break for at least a year, and the issue tracker mentions two bugs that may lead to data loss.

So I uninstalled it. I will look elsewhere for now.

For the record, here is a submission (and comment) by me:

Computer Says 'Guilty' - https://news.ycombinator.com/item?id=27392724 - June 2021 (1 comment)

This article is certainly interesting, but none of these arguments are new so it could have been written five years ago.

It would be interesting to hear what a company like Aurora and their backers were thinking back in 2020. It seems unlikely that they did not come up with these arguments themselves, so what were the counterarguments?

> currently ongoing in the UK

To be precise it is finally getting some of the attention it deserves, both from the public and from the government.

The miscarriages of justice date from 1999 until 2015, and the high court ruling (about the software being faulty) that finally stopped the flow of convictions dates from 2019, almost five years ago. Very little happened since then, and in particular no one has been held accountable.

If that delay sounds absolutely bonkers to you then yes, that is what everyone else thinks as well.

> a belief in the reliability and credibility of IT systems

I found it fascinating to learn that UK law explicitly does (but did not always) encode this presumption:

https://emptycity.substack.com/p/computer-says-guilty-an-int...

(This link is to the substack of David Allen Green, an excellent legal commentator in the UK.)

This explanation may be correct but happens to also fit the pattern of the BBC carrying, perhaps unintentionally, the water for the government.

The more important factoid is that, until the renewed outrage this week, no one in the current UK government was seriously pushing to fix anything whatsoever.

I agree that the hyped-up language is off-putting.

It is however not at all typical for academic publications and blog posts.

In the few times I have seen it before, the author was always a PhD student and a non-native speaker (as it happens from China) and this case is no exception. They were also all smart people, so I am optimistic that with time their writing style will become more attractive.

> But every time TSMC has executed so well.

TSMC or ASML? Or both? I am not trying to be dismissive, just curious about who deserves the credits here.

> At the time they merely shipped the browser with the OS.

> They were also accused of adding new features only in IE which forced websites to deal with incompatible browsers

I do not think this is an accurate representation of history.

First, Microsoft was fighting against the whole concept of a browser as separate from its OS. The fact that one can 'change your default browser', as you so casually say, without changing your OS was a major victory in itself that people worked very hard to ensure.

Second, it was not just 'features' that Microsoft added to IE. They were actively ignoring standards and with Frontpage people could easily generate web pages that looked fine in IE but were a complete mess of impenetrable HTML for other browsers. And when you complained about this the owner would simply add a 'best viewed in IE' icon on their website and start blaming you instead...

In short, at the time it was not at all obvious that a large majority of the web would remain accessible using any other browser than IE. (And similarly for email clients, by the way.) I agree with you that there is still plenty of shady behavior going on, but I am not sure that I would classify the old practices as 'fairly benign'.

The duct tape parts are probably a fantastic moat in itself - ASML's institutional knowledge of where and how to apply such duct tape solutions might be the most difficult to replicate by another company.

The role of quantum mechanics was originally to describe the behavior of individual atoms and molecules. This is the way of the Schrodinger equation or matrix mechanics, the harmonic oscillator, the hydrogen atom, infinite-dimensional Hilbert spaces, quantization, and so on. I would like to call it "hermitian" quantum mechanics since the Hamiltonian is a hermitian operator.

Then there is the quantum mechanics which describes engineered quantum systems like quantum dots and quantum logic gates. Here time evolution is in discrete steps, Hilbert spaces are finite-dimensional, and probabilities are discrete instead of continuous. I think it is apt to call this "unitary" quantum mechanics since one essentially only considers exponentiated Hamiltonians.

It is important not to confuse the two. If you know hermitian quantum mechanics then unitary quantum mechanics is conceptually straightforward. If you know unitary quantum mechanics then you will have a lot of new concepts and mathematics to learn before you understand hermitian quantum mechanics (but of course you may know more about applications).

The programs mentioned in the article teach unitary quantum mechanics: sufficient for engineering, insufficient for physics. If we assume that the engineering world is becoming increasingly quantum then it is perhaps not a bad thing.

I think the trick here is quite clear from the article: these programs simply do not aim for a "decent grasp of quantum". That is at least my take-away from a course that does not consider the hydrogen atom "a real-world example"...

The sentence certainly sounds arrogant, but I have seen such phrasing used also by novice authors who were simply trying to sell a result that they were enthusiastic about. Like the present article's author, these were always non-native speakers.

Nice question, to which I do not know the answer.

Note that Graphics[...] is also used to 'internally' define any internal graphical object, as you can see with InputForm[Plot[...]]. And the chosen syntax seems particularly easy to parse (so as to generate a bitmap, say). So maybe it was designed primarily with that in mind rather than as an API?

According to the documentation Graphics[] has been a part of Mathematica since v1 from 1988. It is probably one of the functions that did not exist in Mathematica's predecessors (like SMP [1]) which largely focused on symbolic algebra. So it might have been up to Wolfram himself to invent a convenient syntax from scratch.

[1] See https://writings.stephenwolfram.com/2013/06/there-was-a-time... but, in typical Wolfram style, insufficient credit seems to be given to other symbolic manipulation products that existed at the time.

But we do apply special relativity to subatomic particles, using a framework called relativistic quantum field theory. It is important to consider relativistic effects when the subatomic particles move close to the speed of light, which they do in particle accelerators. So the outcome of accelerator experiments is described extremely well by relativistic quantum field theory.

The hard part is combining the principles of relativistic quantum field theory with general relativity, or gravity, which describes how matter propagates in a space curved by its very presence. The effects of gravity are indeed completely negligible in particle accelerator experiments, which is why we can describe their outcome in a theory that does not include gravity. But these same effects dominate in other scenarios, for example in early universe cosmology and black hole physics.

Understanding the physics of these other scenarios is one motivation, but on top of that physicists just find it really irksome to not have a single theory that (at least in principle) describes all physics at once, because it indicates that they are missing something fundamental. That is why they are working so hard on topics like string theory.

All of this is is no way related to the article, by the way. First, everything related to the measurement 'paradox' is a big deal in popular science but firmly in the rear view mirror for almost all practicing physicists. Second, the experiments discussed in the article are described perfectly with ordinary quantum mechanics, which in the above context is just a limiting case of relativistic quantum field theory. (In particular, of course doing a measurement means interfering with the system, but that is all understood perfectly well and does not mean that we cannot observe quantum effects.)

Can you provide some evidence for your first sentence?

As far as I can see, this article is about a prediction made by theorists about the evolution of certain quantum devices when you frequently measure part of it. This was a nice theoretical idea which has now been tested experimentally.

The article itself does not seem to contain any claim of quantum supremacy, even for this specific subject. Also, while I think the research is really cute, I do not see it being 'actually useful' in any sense - and the article also does not seem to make such a claim.

You may not have seen it but the tweet is part of a thread. The thread mentions exactly the data you ask for.

And, you may not have seen it but the account is that of the condensed matter theory center at the university of Maryland. The people working there are at https://www.physics.umd.edu/cmtc/people.html .

in 2d: take a square and glue the two pairs of opposite sides together. If you do this with one pair you get a cylinder, and then gluing the other pair gets you a torus. No boundary is left.

In 3d: take a solid cube and glue the three pairs of opposite sides together. Maybe a bit difficult to visualize, but the idea is that if you live in the cube and try to exit it on one side then you re-emerge into the cube from the opposing side.

It is not. Sorry to disappoint. :)

The "dualities" mentioned in the article are about two seemingly different quantum field theories actually being equivalent. See here, for example:

https://en.wikipedia.org/wiki/S-duality https://en.wikipedia.org/wiki/Seiberg_duality

On that subject I enjoyed https://www.nytimes.com/2021/12/08/arts/music/yoko-ono-beatl... .

If you replace "AI" with "self-driving" throughout the open letter [0] then it still makes a surprising amount of sense (and of course any the incoherent bits can be smoothed out by ChatGPT if you prefer).

However I doubt Musk would have signed that version...

[0] https://futureoflife.org/open-letter/pause-giant-ai-experime...

It looks beautiful, but am I the only one who is irked by the fact that the lines cannot be joined at will?

For example, if I type PO_N_ there are two allowed words (POINT and POUND) but this particular visualization does not distinguish them from POIND and POUNT.

For this community it might be useful to stress that the vast majority of practicing theoretical physicists is not in the least worried about any interpretation of quantum mechanics.

I would argue that the idea instead is to try to make predictions for future experiments. In the case of quantum gravity, especially string theory, these might be thought experiments (what happens if you fall into a black hole), technically infeasible experiments (what would a particle accelerator with the size of the solar system produce), or even completely hypothetical (what if the universe would have eleven macroscopic dimensions) but that does not change the underlying mindset.

When it comes to the interpretation of quantum mechanics there is just nothing left to explain. There is no experiment that decides between different interpretations, so that is it as far as most physicists are concerned.

The ideas in the linked article suffer from the same fate: there does not seem to be even a hypothetical way to test them, and the topic is therefore considered one of philosophy more than physics.

Multiplication with multi-dimensional arrays comes to mind (not unlike numpy, actually). Rare bugs when simplifying symbolic expressions. Unconventional definitions of special functions. Probably several others that I am forgetting now.

More importantly there are lots of possibilities for disaster caused by the lack of typing, and complex Mathematica code quickly becomes impenetrable. Oh and version control systems are all but useless for the main ".nb" file format. Again, just like Excel.

Mathematica usage appears widespread in my own domain of theoretical physics, but it is probably used in elsewhere as well.

I use Mathematica frequently and, within the niche that it serves, it is starting to remind me a lot of Excel.

Both are commercial software, have a low barrier to entry, are powerful enough to run the software for a nuclear power plant, have enough footguns to make this a terrible idea, and are so overused that it might be happening anyway.

But I do not think we will get rid of it any time soon.

A sad sight: so much effort and background research went into this paper, and yet so superficial is the author's understanding of QED and renormalization.

In another discussion on HN today Feynman's little book "QED" came up. It is still a great read and I think it conveys the theory's elegance very well. So I would suggest to read it instead of this article.

Unfortunately I do not know any good books explaining renormalization to the general public. Maybe someone else has an idea?

Theoretical physicists are, on the whole, not a silly bunch and there do exist various "mathematically identical" ways to look at quantum field theory. But by the very definition of "mathematically identical" one can find the path integrals somewhere in these alternative descriptions anyway.

Contrary to your stated desire, I actually think that the path integral formulation is in some sense the most "intuitive" and "local". I apologize for not taking the time to explain that here, but let me instead try to convince you that "locality" is not at all obvious in quantum field theory.

One intuitively non-local process is the following. If I start with a state with one electron at the origin at time 0, what is the probability that I measure an electron one lightyear away one minute later? Naively this probability is zero, because the electron that you started with cannot move faster than light. But the actual (and measured, in a less idealized setting) probability is not zero, since vacuum fluctuations can create an electron exactly one lightyear away and you end up measuring that one. That, a physicist would say, is perfectly cromulent with locality of the underlying theory.

I hope this gives a glimpse of how subtle causality (and hence locality) really is, and why at least some believe that path integrals may actually be the most "intuitive" description available.

I think that it is the NYT's policy to not put giant pictures of potential disasters on their front page to avoid being sensationalist.

I would not fault you for disagreeing with that style. Most importantly I think that it risks missing important events: at first they are either not verified (or not verified to be important, like here) and a few days later they are no longer newsworthy. But at least it seems that there is some logic to it.