On the topic of scaling, reversible computations are more energy efficient than non-reversible ones, see also the OP. Outputting the original inputs might seem silly and wasteful superficially but if you discarded them (as "heat"), you'd just be back to building a non-reversible, likely much less efficient gate.
(This is way beyond my area of expertise so excuse me that this might be a stupid idea.)
I assume the following happens: while a (small) subsystem is in "pure state" (in quantum coherence), no information flows out of this subsystem. Then, when measuring, information flows out and other information flows in, which disturbs the pure state. This collapses of the wave function (quantum decoherence). For all practical purposes, it looks like quantum decoherence is irreversible, but technically this could still be reversible; it's just that the subsystem (that is in coherence) got much, much larger. Sure, for all practical purposes it's then irreversible, but for us most of physics anyway looks irreversible (eg. black holes).
Yes, I think that's a stance many physicists take these days. Unfortunately, it's not verifiable. And we also don't have any clue how gravity (which does become relevant at our scales) would fit into this picture.
The problem is that the larger subsystem includes an observer in a superposition of states of observing different measured values. And we never observe this. Copenhagen interpretation doesn't deal with this at all. It just states this empirical fact.
So if I understand correctly, you are saying the observer doesn't feel like he is in a superposition (multiple states at once). Sure: I agree that observers never experience being in a superposition.
But don't think that necessarily means we are in a Many-Worlds. I rather think that we don't have enough knowledge in this area. Assuming we live in a simulation, an alternative explanation would be, that unlikely branches are not further simulated to save energy. And in this case, superposition is just branch prediction :-)
Having tried many other CI systems, all of which ultimately turned out to be subpar, it makes me incredibly sad to discover only now that Cirrus CI is (was?) quite a bit better than them. :( Thanks for the blog post, though!
Shouldn't you always read & double-check the 3rd-party GitHub actions you use, anyway? (Forking or copying their code alone doesn't solve the issue you mention any more than pinning a SHA does.)
Double checking Github actions does not mitigate threats from supply chain vulnerabilities. Forking an action moves the trust from a random developer to yourself. You still have to make sure the action is pulling in dependencies from trusted sources which can also be yourself depending on how far you want to go.
You could get in touch with GP by googling for his company (see profile), finding his name through the company website (he's the CEO), and then googling for his LinkedIn/X accounts.
I would love that but not so much for pedestrians as for cars that don't see me on my bike. Ideally, the "bell" would automatically honk at them very loudly when they get too close.
> Trusted Execution Environments (TEEs) like Intel SGX and AMD SEV-SNP and in general hardware attestation are just f*d. All their keys and roots are not PQ and I heard of no progress in rolling out PQ ones, which at hardware speeds means we are forced to accept they might not make it, and can’t be relied upon.
Slightly off-topic but: Does anyone know what the Signal developers plan on doing there to replace SGX? I mean it's not like outside observers haven't been looking very critically at SGX usage in Signal for years (which the Signal devs have ignored), but this does seem to put additional pressure on them.
I'm not sure who particularly cares about the stuff Signal is doing with SGX anyway. It always struck me as a 'because we can' move and if you're paranoid enough to worry about it then you're probably paranoid enough to not trust any manufacturer-based attestation anyway (All SGX does is make Intel the root of trust, and it's not like Signal would be less secure than any other third party if SGX were broken).
> I'm not sure who particularly cares about the stuff Signal is doing with SGX anyway.
Security researchers like Matthew Green seem to care[0], the Signal people surely do, I myself do, too. Isn't that enough to raise that question?
> if you're paranoid enough to worry about it
You make it seem like that's an outlandish thought, when in reality there have been tons of reported vulnerabilities for SGX. And now QC represents another risk.
> it's not like Signal would be less secure than any other third party if SGX were broken
That's a weird benchmark. Shouldn't Signal rather be measured by whether it lives up to the security promises it makes? Signal's whole value proposition is that it's more secure than "third parties".
I mean, if you're worried about Signal being a bad actor you also should probably be worried about Intel being a bad actor, and they hold the keys to SGX (especially because the biggest threat, if you're worried about this at all, is going to be governments compelling the involved companies to hand over data or attempt to intercept messages). And Signal is also a third party to your communications, that's how it works. But nothing about SGX makes me think Signal is more trustworthy, it doesn't meaningfully remove actions that they could take to compromise my communications.
Agreed, I never put much trust in Intel SGX, either. I was bringing up the whole topic rather because I'm secretly hoping it will force Signal to revisit the whole Signal PIN debacle and they will ultimately find a better solution.
I never said I was considering any.[0] I'm strictly interested in what Signal is doing to keep (or even improve) its security guarantees.
On that note, Signal wouldn't even depend on Intel SGX for security nearly as much if Signal PINs weren't user-chosen but instead auto-generated with enough entropy. Yes, contact discovery through phone numbers would still be challenging, but secure value recovery[1] just requires a key with enough entropy.
[0]: For the record, Threema doesn't store your contact list server-side, unless you explicitly opt in. Similarly, now that Signal supports usernames, my understanding is that one could use the app without uploading one's contact list in plaintext.
Is anyone here actually reading the article? Yes, they really made a gain of $15B:
> But instead of refining and transporting the gold, it opted to sell the bars and purchase new bullion in Europe. […] Due to rising gold prices, the move helped the bank to generate a capital gain of 13 billion euros ($15 billion),
This doesn't make sense. If they first sold the bars held in the US, then the gold prices rose, then they bought gold in Europe, how the hell did that amount to a capital gain of $15b? How exactly do prices rising over the course of the process lead to these $15b?
First thought: Maybe they bought the gold first? Or the gold price was at a temporary high when they sold it?
Second thought: The numbers don't seem to check out: 129t are 4,147,456.307 troy ounces (1 troy ounce = 31.1034768 g). The total gains of 15e9 USD would thus correspond to gains of $3,616.68 per troy ounce, which seems excessively high, given that today's gold price is at ~$4,712. Even if they sold everything at the current all-time high of $5,589.38 on January 28 (and that's a big if), they would have had to buy for not more than $1,972.70, a price we last had in fall 2023.
Imagine they bought the gold in the US for 1b and sold for 16b. Yes they turned around and purchased 16b of order gold immediately but there's was still a transaction where they sold an asset for more than they bought it.
If you bought your house for $500k 20 years ago, sold it today for a million, then bought it again tomorrow for a million, would you describe that to your friends as having just made $500k? Like yes in the most pedantic technical accounting way it's a gain. In spirit I would call this an unrealized gain
No, you’d remark that your house has appreciated in value over the past 20 years. But you wouldn’t have realized any of that gain until you sold the house - the point being that the realization is the actual taxable event, which is why it matters from the pedantic technical accounting POV. The fact that you turned around and bought another house just means you’re doing something new with your realized gains. Now you have a new cost basis. Maybe that’s what you’re saying with “unrealized gain” though.
Sure in the spirit it's an unrealized gain but wouldn't the tax man consider it a realized $500K capital gain? seemingly this is would be the more appropriate way of categorizing it?
It's more that the english ain't parsing, for some at least.
The mining.com quote is classic weasel phrasing, seemingly meaningful yet disturbingly ambiguous:
Due to rising gold prices, the move helped the bank to generate a capital gain of 13 billion euros ($15 billion), bringing it to a net profit of 8.1 billion euros for the 2025 financial year after a net loss of 7.7 billion euros in 2024.
So, the move helped the bank generate ...
Just as, say, one guy helped four others push a car back up on the road.
We've been given, accurately or not .. likely true, figures on how the bank did over a period, we've also been told the gold movements helped with that ... so they almost certainly kicked in at least $1.
The claim is that rising gold prices lead to gains of $15b. As in they started with 129 tons of gold in the US, then they sold that and bought gold in Europe, and in the end, due to rising gold prices, they had 129 tons of gold in Paris plus $15b extra cash. Please explain a hypothetical course of events which makes this plausible.
Keep in mind that 129 tons of gold is worth just a bit more than $15b, so small market fluctuations on the scale of 10% isn't enough by itself.
They purchased 129 tons of gold in Europe. Their asset position did not change: they converted cash to gold of the same value.
They then sold the 129 tons gold in the US vaults for $16 billion. That gold was originally purchased I'm guessing many decades ago for $1 billion. The have a book profit of $15 billion and still have 129 tons of gold.
They captured some of the appreciation in gold value as a realised profit on their books.
Their balance sheet did not change, just their income statement
The US gold would have been on the books at the original purchase price, so something like US$35 from 1910 (when a penny had a purchasing power of 38 cents now). Having deemed it more efficient to sell that gold and buy the same amount to replace it, the new gold is on the books at the 2026 purchase price. As the 2026 money price is far higher than the 1910 price, the value on the books shows a dramatic realized capital gain.
No gain would have shown for the gold that was simply moved, even though in this case the buying and selling was simply a more efficient way of doing the equivalent of moving the gold.
Gold that was simply moved wouldn't show the same gain.
That makes more sense, thank you! Though do gold assets on the books really never get adjusted? I guess that's up the central bank to decide but I would find it surprising.
It's the rules of how they must account for the value of the gold they have. Gold is valued at the price paid. Then, it is valued at the price sold. If there is no sale for more than a century, it stays on the books at the price paid. Once a transaction happens, the numbers update. Then, the gain that everyone knows is there is 'realized'. It's like if you mined Bitcoin in the early days. Your gain is only 'realized' when you actually sell it. Until then, it is only theoretical.
Mark-to-market accounting systems are one way to deal with this quirk, but they create their own issues.
What I was trying to get at is that there are other ways to update asset valuations besides daily (market-to-market) and once (price paid) – those are just the extreme ends of a spectrum. What makes sense really depends on the asset class and how long you're holding the positions. As for "It's the rules", I'm aware that there are strict accounting rules for companies and regular banks, but do those really apply to the central bank in the exact same way? (A central bank typically operates on a much longer time scales.)
If the central bank doesn't follow rules, who would trust it? The central bank's entire purpose is to put national trust into individual banks; both assuring investments (accounts) and establishing base (prime) loan rates.
A central bank answers directly to the government, not the judiciary. But it still answers to power, and follows established rules.
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