I had a contract with a company in the SF Bay Area back in 2011-2012. I spent 50% of my time in the Bay Area, despite living in Florida. I often stayed in a San Francisco hotel and walked to a commuter bus that would take me to corporate headquarters.
I visited SF on other occasions in 2015 and 2022. The contrast between 2011 and these dates was staggering. In 2011, I did not have to step around human feces in the street. There was and is always a significant presence of homeless people -- who don't bother me -- but at least back then, I felt pretty confident walking at night through any part of the city, even the Tenderloin. In 2015? It was pretty bleak. Crime was up, and folks were much more aggressive. In 2022, I had my head on a swivel. I'm used to significantly more, uhh, vigorous urban areas, and SF started pinging my situational awareness in 2022 like it didn't eleven years earlier.
Don't get me wrong: SF is a kitten compared to Chicago, Detroit, or Baltimore. But, it's sad that it has descended so far. It is still a charming city that I'd love to visit again, but some of that charm has been lost.
Duelling opinions! (Not really -- downtown SF has had a lot of trouble in the last few years, though as Noah notes, it's been feeling a bit better lately).
However, the trajectory isn't quite that clear, at least over a longer timeline and across the whole city. Back in the 1990s, a lot of downtown was very dodgy feeling, though mostly a block or so away from Market. Market itself varied across its length -- by the time you got to Van Ness it was becoming sketchier. Its status dipped and weaved as the city's fortunes shifted -- not necessarily corresponding exactly to economic success, but by 2011 downtown I think it was fairly "back'.
Other neighborhoods did not do so well during that time, to my memory. The strange thing about 2011 was that San Francisco survived the 2008 crash fairly well economically, so on the surface it was doing well, especially by comparison, but underlying it was a big upswell in the problems that would overtake it in 2015-2022. I'm not sure they were visible everywhere in the city.
I guess what I'm trying to say here is that San Francisco is a heavily boom and bust city, with lots of neighborhood variation in fortunes -- I think plenty of people would argue that Market's upturn has come at the expense of pushing problems out to the periphery. But I wouldn't disagree that it's still digging itself out of the COVID hole, five years on, and despite a lot of potential tax income from the current boom.
I have no doubt that SF has its ups and downs. My comment was based on my subjective experience. I'm sure we've all seen the Hollywood accounts of SF in the Dirty Harry movies. It was once bad enough to get such an impression.
I was just sad to see SF in a bust, because I genuinely enjoyed it in 2011. I can only hope that this slump resolves and that the folks who are down and out on the streets get the help they need.
2022 and 2026 SF are radically different. Just read all the raves about the current mayor. Maybe about 5% of SF has crime issues. Unfortunately that 5% is near all the convention centers and big hotels so travelers impressions tend towards the negative.
>A note to my fellow San Franciscians: I’m sorry. I know. There’s always some story in the East Coast press about how our city is dying. San Franciscians hate—HATE—these pieces. You’re a stooge and a traitor for writing one. When I set out reporting, I wanted to write a debunking-the-doom piece myself. Yet to live in San Francisco right now, to watch its streets, is to realize that no one will catch you if you fall. In the first three months of 2023, 200 San Franciscans OD’d, up 41 percent from last year.“It’s like a wasteland,” the guard said when I asked how San Francisco looked to him. “It’s like the only way to describe it. It’s like a video game — like made-up shit. Have you ever played Fallout?”
>I shook my head.
>“There’s this thing in the game called feral ghouls, and they’re like rotted. They’re like zombies.” There’s only so much pain a person can take before you disintegrate, grow paranoid, or turn numb. “I go home and play with my wife, and we’re like, ‘Ah, hahahaha, this is SF.’”
This risk factor is similar to one I brought up during architectural review of an IoT company I helped to build. It's why the identity certificates our devices used were entirely disconnected from domain names, and why the discovery protocol I put together did not rely on registered domains, but could use these as an untrusted part of discovery.
Domain names are leased. Things that are leased can disappear. The company leasing these assets could go bankrupt. They could weasel their way out of agreements as Verisign has done here. Any identity that is grounded in leased assets is built on shaky ground. It's also why I'm dubious of the way that e-mail addresses have become tied to online identity.
I'm not saying that what Verisign has done is right, but this behavior is expected. Those of us who went through the (dot) bomb era remember just how shaky this infrastructure can be.
I'm sorry that .name people are going through this. Even though it's a risk I expected, that doesn't make this okay.
"Online identity" seems like a castle built on quicksand in every single case.
What's your account tied to?
E-mail? That's usually on a mail server owned by someone else. If not, it's still on a domain owned by someone else.
Phone number? Definitely owned by someone else.
The only account that's reliably "yours" is one that asks for a login, a password, maybe a TOTP, and absolutely nothing else. Because everything else is introducing "things owned by a third party" into the equation.
You've hit the nail on the head. That's why I strongly preferred email and password login, backed by a keepass(xc) store to hold the data. Owned by me, backed up, impossible to take from me, the works. Sure, most of the time I have to verify my mail address, but after that the account is mine. Well, okay. On some services, I have to "confirm the new device" I'm loggin in from, so I still need access to my mail.
Weeeell... Some services I use seem to have switched to a magic link EVERY TIME for login. No password anymore at all. And all of a sudden, my mail account is the single point of compromise for these accounts.
And there is absolutely nothing that I can do. If the mail is hosted by someone else, they may terminate my account at a whim. Or give it to someone else who happens to have convinced my phone provider to hand them a sim card with my number on it. If I do self host I still need a domain, and I can never really own a domain, only rent it from somewhere. So, whenever that lease goes up, my account is compromised by default.
I really hate that this problem seems still unsolvable. Keybase had the right idea, but no one used it and they got aquihired by zoom during the pandemic...
It's the same reason I was nervous moving our company domain to a .ai TLD; your entire presence, identity and trust is now beholden to the whims and political winds of a Caribbean island smaller than Topeka.
It's not anymore: "in April 2026 the implementation of the agreement was put on an indefinite hold due to opposition from US President Donald Trump." So whatever ICANN was going to do with .io, it's all on hold for now.
This article comes close to making a fallacious argument about formal methods, which is that formal methods aren't useful unless you can exactly specify how something works.
I use model checking (a form of formal methods) daily. I separate the process into three domains: things that must be fully specified, things that can be fully specified, and things that, with the appropriate mitigation, need only have certain properties verified. Most software fits just fine in the latter category. Spend your time on fully verifying process isolation, cryptography, certain core runtime functions / behaviors, and logic relating to authentication and authorization. Everything else can be partially verified, which is much easier. Verify termination, no UB, memory safety, and that function contracts, data structure invariants, and API boundaries are followed.
A PDF implementation, a web browser, or a random server application fits cleanly into this decomposition. It matters little if the PDF is rendered oddly, or if the web browser can't interpret a page. But, it matters greatly if these errors could result in a vulnerability that could be exploited, or to a lesser extent, if these errors resulted in the software crashing.
Pure formal methods is academic. Apply engineering to this, and you get a real world and practical framework for making software safer.
Do you find that given a formal spec an agent can write complete implementation you don’t have to even read?
I keep thinking about various ways of “pushing back” on an agent, shortening feedback loop and extending what we can grantee about results.
At the most low level we can nullify probability of the next token if that token is not desirable (eg json schema enforcement under constrained inference), this is the fastest pushback. Various compiler checks, linters, unit tests, exotic type systems, e2e tests, production traces. Wondering what else is out there.
On a tangent, iirc pascal allowed single-pass compilation, so I wonder if we can embed compiler directly into inference, sort of constrained inference on steroids.
I think that reading and reviewing software is responsible.
Source code exists for humans to read first, and for computers to read second. Programming languages are unambiguous, and most languages take well to abstraction. Software can be written at a level that is appropriate for human review. Boilerplate can be avoided. It's well written when it is easy for stake holders to understand directly, without translation and without an LLM to summarize it.
Software should be the output artifact of the process, because it exactly describes the behavior of the system. The formal specification explains how the software embodiment must work, and in constructive proofs, it's even possible to extract the software embodiment from this specification. But, from a practical perspective, this is too time consuming. Instead, specification should be written to explain the rules that software must follow, instead of the exact behavior. In this case, the source code is still an important artifact, and it should be reviewed and improved upon as part of the process.
You can define what constitutes undefined behavior without defining the behavior itself. Programming language definitions rely on this. So “verifying no UB” means verifying that a program is not performing any operations that have undefined behavior. Simple example: dereferencing an uninitialized pointer.
I get that, but I meant more philosophically, why is it especially useful to verify that no behavior is undefined if the defined behavior is also not defined, other that according to the compiler spec?
I may be missing what you're asking. To extend the example I gave, it's very useful to be able to verify that a program never dereferences an uninitialized pointer. In general, it's very useful to be able to verify that a program doesn't do anything that could cause UB.
But this level of formal verification gets you to the level of confidence you’d have if you had written the program in Rust or Java in the first place. The original post was talking about formally verifying what the system does as a whole, not just verifying the absence of a certain class of errors. I’m not questioning the value of eliminating null pointer dereferences that do exist, just the value of holding a formal proof of the absence of null pointer dereferences in a certain piece of code, given that there are many other possible bugs that that code could contain.
I mean, if I had a formal proof that my banking system could never double-spend money, that could be a useful property that someone would want to know about the system. If I have a proof that my banking system never dereferences a null pointer, there’s not very much I can be sure of on the basis of such a proof.
The difference is that Rust and Java can only verify certain properties. I can build model checks to verify any property that I can discharge with an SMT solver, which is significantly more powerful. For instance, I can build function contracts that verify that if a function succeeds, it performs certain actions, and if it fails, it does not. I can verify that a function properly manages external resources, performs authorization checks, or always follows data structure invariants.
I don't need to build full formal specifications to do this. I can verify just the subset that is important. I can do more than what Rust or Java provides. I can add more rules that must be followed, or in cases where it doesn't matter, I can relax specific rules without reaching for clumsy annotations like "unsafe", or using an FFI.
Yeah again fair enough. You can use formal methods to provably maintain invariants that are useful to you in development without shipping formal proofs of full system behavior.
If you had enough money to convince AMD to sell you the tapeout, and if you could hire a fab using a similar process, you could make a new CPU. Other than that... probably not.
The next best thing would be buying a replacement.
Security researchers do face legal harassment all of the time. They may not be charged with or convicted of felonies, but it is a game that they need a lawyer to navigate all the same. In a just world, the kind of weaponized incompetence that these frontier model builders are definitely guilty of should be felonies of their own.
Building a system that is meant to chain attacks and placing it in insufficient containment -- when any reasonable engineer could point to this containment and show how it is insufficient, both before the act and after -- shows that they were operating a dangerous system without either the knowledge nor the safeguards required to keep it from harming others. Instead, they are allowed to treat their own incompetence as evidence of advanced and existential "cyberthreats".
But, it's pretty clear based on how they one-up each other on these attacks that they are engaging in regulatory theater. Their behavior generates headlines, stirs up fear in the public, and then their lobbyists march on Capitol Hill demanding regulation now. Regulation that conveniently favors them at the expense of any competition. They are trying to use rent seeking as a way to stymie competition and pull up the ladders behind them. It's not just malicious. If it can be proven, it's collusion: antitrust dressed up as public policy.
Personally, I see these language fights as being a bit pointless. They are trying to optimize at the wrong layer. Unless one is working with a dependently typed language, which requires a proof assistant to discharge type checks, then it's all just a question of where you make the trade-off. Don't care about memory leaks or deadlocks as part of your soundness guarantees, but can't have GC? Use Rust. Okay with runtime overhead to verify checks? Consider fil extensions.
If you want to go deeper, skip the language wars entirely. Tooling does what these languages can't do. I have had great success model checking C with CBMC. Not only does this prevent memory safety issues (including memory leaks), but this also prevents deadlocks. Bonus: you can write user contracts and invariants to verify that every execution path of a function fulfills these contracts and invariants.
Kani comes close with Rust. It doesn't yet have decent concurrency support, but there is nothing that prevents this from being added in the future. The ability to write custom contracts and enforce custom invariants more than makes up for its lack of concurrency support. Similar technology could be used or adapted for Zig or C++.
Use whichever language you like. Just, please look into model checking it. The technology scales just fine, once you get over the learning curve and learn how to use compositional verification.
There are plenty of open core alternatives that replicate the architecture and ISA. Many of these are cycle accurate. Some have been tape-out proven. Hobbyist retro-computing enthusiasts who wish to build a Z80 system still have options even once new old stock and recovered CPUs become scarce.
Wait... wasn't it already understood that relativity influences electron orbits of heavy elements? I clearly remember being taught some of this in physics, in the mid-noughties.
For instance, we know that gold gets its color from relativistic effects.
Seems to be the first time this was confirmed via direct experimental observation of the orbitals:
“This idea that relativity is important in heavy elements has been around since the 1970s,” said Lai-Sheng Wang, a professor of chemistry at Brown and the study’s corresponding author. “But we show direct spectroscopic evidence that what we learned in high school about chemical bonding isn’t true in heavy elements."
The Dirac equation which is the equation for describing the wavelike behavior of electrons. It predicted the existence of antimatter and particle spin.
You start with the Schrödinger equation, add relativity to get the Klein-Gordon equation which is a mess because it's second order in time involving negative probabilities, if you in ways "take the square root" of it you get the Dirac equation.
Relativity has been part of the understanding of electrons since 1928.
To add to this, this "square root" operation done to derive the Dirac equation is where spinors i.e. electron spin i.e. the Pauli exclusion principle i.e. the reason atoms exist at all comes from. Likewise antimatter. The "second order in time" of the Klein-Gordon equation comes from adding relativity and the "fix" reducing that to first order time is the source of antimatter and spin.
So yes very much so relativistic effects are a foundational part of QM.
Thanks for the insights. I am interested in learning all this stuff. Am currently going through just Schrodinger's Equation. Do you have book recommendation(s) that include insights everywhere just like what you shared? Thanks.
These are books to train physicists, accessable-ish to a math heavy engineering undergraduate degree holder. The insights above are my own and extractable from this material but not necessarily stated out loud (unless I'm unconsciously plagiarizing which is entirely possible)
* David Griffiths - Introduction to Elementary Particles
* Chris Quigg - Gauge Theories of the Strong, Weak, and Electromagnetic Interactions
In general, yes. Spin-orbit coupling and relativistic effects in heavier elements is not new. A rather... significant elements where this was studied was uranium (and plutonium, of course). Even napkin maths show that for heavy elements, some of the electrons have relativistic velocities.
This discovery is about a (seemingly, I haven't been keeping up too much) new case of one specific bond in one specific ion. Do not read the university's breathless press release, go straight to the article. The third sentence of the editor's summary is "It’s long been clear that this model starts to fray when the atoms get heavy enough for relativity to come into play".
Yes, I was taught that relativity is a significant part of quantum chemistry equations in gold atoms 25 years ago. The idea is quite old and the title is misleading.
I don’t understand how something that has no clearly defined position like an electron can have a well defined speed. I thought I had understood that at that level, particles are more like clouds, or vibrations in the quantum field, and they had no well defined position until you tried to measure it, causing its cloud to collapse to a smaller region. But if non observed electrons can have a speed that defines the color of a material, that whole understanding seems to be wrong! Where is the error? Are all atoms on a piece of gold being “observed” in the quantum sense?? Even if we just capture the spectrum? Or it’s something else??
The idea is that it has not a clearly definite position, but it has a distribution of probability to find it that looks like a "cloud" https://en.wikipedia.org/wiki/Atomic_orbital
In a more abstract sense, has not a clearly definite speed, but it has a distribution of probability to find it in a speed graphic.
The distribution of position and speed are defined by an equation and you must add a relativistic correction to the classic version. For lighter atoms you can just ignore the correction. For heavy atom (like Bismuth in this case) the correction is important.
Informally, the correction is important only when the "average" speed is fast enough to be somewhat close to the speed of light, like 50%c.
The correction changes the energy of the expected distribution of position and speed, and the energy. When an electron jumps from an orbital to another orbital, the difference of energies is related to the color.
> Are all atoms on a piece of gold being “observed” in the quantum sense??
[Ignoring that "observer" is a very misleading word and causes a lot of confusion, but it's the standard one and we are stick with it...]
The observation is only of the energy level of the orbital electron. We know the energy, but we don't know the position or the speed. When you observe some quantum object you don't get magically all the properties, only one of them, in this case the energy. In other experiments you can get only the position, in others only the speed. [And there are a lot of weird cases and technical details.]
(Newbie here). And then going further, shouldn't there also be acceleration and its distribution? It says classical models could not explain why accelerating electrons were not radiating. If acceleration also shows up in QM, then ... a distribution of radiation?
[Sorry for the delay. I really had to watch that soccer game and kids don't have school on Sunday.]
There is an acceleration distribution, but the acceleration operator is strange. I don't remember the details and a quick google search confirms that it's strange.
It's complicated... let's oversimplify some details...
In QM the electron must jump from one orbital to another, and the difference in energy is emitted as radiation as a photon. If the electron jumps from A to B, then B must be empty. So if A is the orbital with less energy then it can't emit. Also if B is full, it can't emit.
For a big enough system, there are plenty of options for B and you get a very good approximation that is the classic rule that says that accelerating electrons emit photons.
There are weird cases, like in a neutron star, there are too many electrons trapped by gravity so all possible B are full, and you have electrons that can't emit.
It you want a tabletop experiment, the keyword is "fermion gas" that are gas of fermions (like electrons) that are very cold and very dense and they have a strange repulsion that is not explained classically. It is caused because there are jumps that are forbidden because the destination is full. (If you heat them or give them more room to be diluted, this strange repulsion almost disappears and you can aproximarte them as a classical gas.)
> a distribution of radiation?
If you measure the radiation far away, you have a distribution of possible colors/energy of the photon, because the electron may choose to jump form A to B1, B2, B3, ... This is like the lines color of gas lamps.
If you measure close enough, you have to draw Feynman diagrams and the photons may have a slightly different value of color/energy. But it's complicated and I'm not sure of the details. I guess it's related to the acceleration distribution, but I'm not sure of the details again.
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The easy answer is that "acceleration -> radiation" is only a useful approximation when the system is big enough to ignore the quantum effect.
The hard answer is probably that you have to study like 10 years of physics to be sure and explain me the details. :)
"High speed" here can be taken in terms like this: the phase of the wave function changes rapidly with position and time. (Changing with position -> a superposition that's heavy on short wavelengths, high momentum; with time -> high frequency, high energy.)
Re "observed all the time": when gold interacts with light, the light's normally of a strength that's a small perturbation on the fields internal to the atom, which is basically why you can treat the atom/light-field system as two weakly coupled quantum systems. It's an "observation" when the light leaves a classical trace such as a current in a CCD.
(I don't expect this to leave you unmystified about QM, but hopefully a bit clearer about it.)
subheader explains the article in case you were wondering
> Researchers have shown the first direct experimental evidence that the textbook triple bond structure breaks down in heavy elements, where relativity makes the rules.
I visited SF on other occasions in 2015 and 2022. The contrast between 2011 and these dates was staggering. In 2011, I did not have to step around human feces in the street. There was and is always a significant presence of homeless people -- who don't bother me -- but at least back then, I felt pretty confident walking at night through any part of the city, even the Tenderloin. In 2015? It was pretty bleak. Crime was up, and folks were much more aggressive. In 2022, I had my head on a swivel. I'm used to significantly more, uhh, vigorous urban areas, and SF started pinging my situational awareness in 2022 like it didn't eleven years earlier.
Don't get me wrong: SF is a kitten compared to Chicago, Detroit, or Baltimore. But, it's sad that it has descended so far. It is still a charming city that I'd love to visit again, but some of that charm has been lost.
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