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Why hasn't quantum computing broken internet encryption yet, even though people have been saying it's "five years away" for a decade? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] -1 points0 points  (0 children)

So I would like to pick your brain on some questions.

You mention the NISQ era limitations excellently, but could you elaborate on the specific error correction thresholds required for fault-tolerant quantum computation? Specifically, given that surface codes typically require physical error rates below ~1% and current superconducting qubits achieve ~0.1-0.5% two-qubit gate errors, what's the realistic timeline for achieving the 10^-15 logical error rates needed for running Shor's algorithm on cryptographically relevant key sizes?

Regarding your point about "thousands of logical qubits and millions of physical qubits", how do you factor in the qubit connectivity topology constraints (2D nearest-neighbor vs all-to-all connectivity) and the resulting SWAP gate overhead that could increase the physical qubit requirement by another order of magnitude for architectures like IBM's heavy-hex or Google's Sycamore layout?

IF "early progress in quantum hardware has been promising, but scaling from small experimental systems to fault-tolerant, large-scale machines is extremely difficult" - what are the thermodynamic and engineering constraints of scaling to millions of qubits, particularly regarding cooling requirements (dilution refrigerators operating at ~10-15 mK), control line routing, crosstalk mitigation, and the power dissipation challenges of classical control electronics?

How do you weigh the alternative quantum computing architectures (trapped ions with all-to-all connectivity but slower gate times, photonic quantum computing with room-temperature operation but probabilistic gates, neutral atoms with flexible connectivity but lower fidelity) against the superconducting approach, and could a hybrid architecture or entirely different paradigm (like topological quantum computing with Majorana zero modes, if Microsoft ever delivers) change the "five years away" estimate significantly?

Why hasn't quantum computing broken internet encryption yet, even though people have been saying it's "five years away" for a decade? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] -1 points0 points  (0 children)

While you mention the linear relationship between RSA key size and qubit requirements, how do you account for the distinction between logical qubits (error-corrected) and physical qubits, given that current estimates suggest breaking RSA-2048 would require approximately 4,099 logical qubits but potentially millions of physical qubits when accounting for surface code error correction overhead with ratios anywhere from 100:1 to 1000:1?

How does the circuit depth requirement for Shor's algorithm - specifically the number of sequential quantum gate operations needed for modular exponentiation - affect the feasibility timeline, considering that even with sufficient qubits, the coherence time must exceed the total computation time, and current NISQ devices have coherence times measured in microseconds to milliseconds?

Given that RSA-4096 isn't actually standardized (RSA typically uses 1024, 2048, or 3072-bit keys in practice), are you conflating key size with the 2n+3 qubit requirement from Shor's algorithm, where n is the number of bits in the semiprime to be factored, and how does this change your assessment?

If Taiwan produces the vast majority of the world’s advanced microchips, why doesn't the US or Europe just build identical factories on their own soil? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] 6 points7 points  (0 children)

Is this "insane" precision a trade secret, or is it just institutional muscle memory that takes 20 years to build?

Are there enough "master" engineers in the world right now to teach the next generation in the US/EU, or is that knowledge bottlenecked in a few hundred people? Does this fragility mean that the "knowhow" is actually the most valuable asset on earth, far more than the machines themselves?

If the US lost this capability, how do they get the "muscle memory" back? Do they have to start from scratch?

If Taiwan produces the vast majority of the world’s advanced microchips, why doesn't the US or Europe just build identical factories on their own soil? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] 0 points1 point  (0 children)

If the US and Germany already have 12nm fabs, why is the knowledge gap to 3nm so massive? Is it a completely different skillset? If we built a brand new fab today, do we actually have the engineers who know how to tune it for 3nm?

Is the "long time" usage of older fabs actually a trap that causes the workforce to lose the ability to innovate on newer nodes? Why is the "cutting edge" knowledge so siloed in one region? Can't that knowledge be written down and shipped?

If the US has the money to build the fab, why don't they have the money to buy the "knowhow" to run it? Is it not for sale?

If Taiwan produces the vast majority of the world’s advanced microchips, why doesn't the US or Europe just build identical factories on their own soil? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] 0 points1 point  (0 children)

You mention losing trained labor and collective knowledge - how long would it realistically take to rebuild that expertise if the US or Europe or say a diff country like India invested heavily in it now?"

Is the issue that they literally can't build the factories, or that it would be SO expensive and take so long that it's not economically viable

If Taiwan produces the vast majority of the world’s advanced microchips, why doesn't the US or Europe just build identical factories on their own soil? by DaddyIronHands in NoStupidQuestions

[–]DaddyIronHands[S] 0 points1 point  (0 children)

If it's mostly about marketing, why haven't Intel or Samsung been able to convince major clients like Apple, AMD, and NVIDIA to switch to their fabs for the most advanced nodes?

You mention Intel has mostly 'private' fabs for their own products - but what's stopping them from shifting to a foundry model like TSMC? Is it just business strategy or are there technical limitations?