Comment by cgcrob

Microsoft Research entire point is that their approach will allow

  "fault-tolerant quantum computing architecture based on noise-resilient, topologically protected Majorana-based qubits."

Roadmap to fault tolerant quantum computation using topological qubit arrays https://arxiv.org/abs/2502.12252

The issue isn't really impurities and noise, quantum error-correction solves that problem. The issue is that the supporting technologies don't scale well. Superconducting qubit computers like google's have a bunch of fancy wires coming out of the top, basically one for each qubit. You can't have a million wires that size, or even a smaller size, so the RF circuitry that sends signals down those wires needs to be miniaturized and designed to operate at near 0K so it can live inside the dilution refrigerator, which is not easy.

Microsoft's technology is pretty far behind as far as capacity but the scaling limitations are less significant and the error-correction overhead is either eliminated or smaller.

Based on what i read it seems a lot of algorithmic work is required to even make them useful. New algorithms have to be discovered and still they will only solve only a special class of problems. They cant do classical computing so your NVIDIA GPU probably may never be replaced by a Quantum GPU.

Hopefully not, besides quantum physics simulations the only problems they solve are the ones that should remain unsolved if we're to trust the integrity of existing systems.

As soon as the first practical quantum computer is made available, so much recorded TLS encrypted data is gonna get turned into plain text, probably destroying millions of people's lives. I hope everyone working in quantum research is aware of what their work is leading towards, they're not much better than arms manufacturers working on the next nuke.

i vaguely remember reading an article about solving the correlation between quantum decoherence and scaling of qubit numbers. i dont understand quantum computers so take it with a grain of salt.

but here’s what perplexity says: “Exponential Error Reduction: Willow demonstrates a scalable quantum error correction method, achieving an exponential reduction in error rates as the number of qubits increases125. This is crucial because qubits are prone to errors due to their sensitivity to environmental factors25. ”

> last time I checked the record was 80 qubits

It has progressed since: IBM Condor (demonstrated in december 2023) has 1121 qubits.

You're certainly allowed to get excited about it as long as you're patient and don't wildly overinflate the realistic timeline to net energy production. Similarly, nobody will stop you from hyping up quantum computation as long as you're not bullshitting usecases or lying about qubit scaling.

In the wake of cryptocurrency and AI failing to live up to their outrageous levels of hype, many people on this site worry that the "feel the AGI" crowd might accidentally start feeling some other, seemingly-profitable vaporware to overhype and pump.

You can't use shor's algorithm with current quantum computers.

But if we were to get bigger and better quantum computers, we should use shor's algorithm. And that would, in fact, break the crypto behind HTTPS, SSH, smard-cards, and effectively all other forms of asymmetric crypto that are in use.

There is a question how likely bigger and better quantum computers are. A decent case can be made that it is unlikely they will grow fast. But it is going to far to say that shor's algorithm is useless because current quantum computers aren't good enough. You can't dismiss the possibility of quantum computer growth out of hand.

I think I heard that 77 was factored as well

Or the quantum computer is computing which world you open the box in.