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0 pointssfpotter3y ago0 comments

"The simple reason for this is that despite years of effort nobody has yet come close to building a quantum machine that is actually capable of solving practical problems. The current devices are so error-prone that any information one tries to process with them will almost instantly degenerate into noise. The problem only grows worse if the computer is scaled up (ie, the number of “qubits” increased)."

+ 5 subsequent paragraphs

0 comments

solveit3y ago

The current mainstream view is that QC is a very hard but tractable engineering problem. There is no fundamental reason for quantum error-correction to not work, and a demonstration that it cannot would be a major and surprising breakthrough in fundamental physics. This has been our state of understanding for a couple of decades now, and the progress we have been seeing is consistent with this view.

To be clear, there are people making sophisticated arguments for fundamental barriers to quantum computation. For instance, the quantum-skeptical mathematician Gil Kalai writes about his thoughts on recent progress on QC at (https://gilkalai.wordpress.com/2022/05/26/waging-war-on-quan...). His view is considerably more nuanced than this FT article, and much more conducive to learning and discussion. I hope you take the time to read it, and I think I'll submit this to HN main as well.

packetlost3y ago

As someone working in QC control systems, this holds up with my experience. We're fundamentally dealing with tough engineering problems, primarily on the hardware side of things. To be clear, these systems are very complex and rely on a multitude of software and hardware working, and working well. I'm of course biased, but I lean towards a positive outlook on QC.

epgui3y ago

It's not clear and obvious that this and the following 5 paragraphs mean that the technology is "fundamentally unsound" either. It's just that there are big problems we haven't yet figured out how to work with.

Though it is true that we don't know the degree to which we will be successful at developing this technology, and we know there are fundamental properties we will need to contend with (for better and for worst), this is entirely consistent with how "early technology" develops.

AFAIK, even "commercially oriented" quantum computing projects are better understood as being in a research stage at this time. When you do research, in general, it feels daunting and it's not at all obvious that things are going to work. (my field is biochem)

curt153y ago

Some quantum error correcting codes were recently demonstrated experimentally: https://physics.aps.org/articles/v15/103

fsh3y ago

The first experimental demonstration was 18 years ago: https://www.nature.com/articles/nature03074

The problem is that none of this scales beyond toy systems with a hand full of qubits. As soon as you try making it bigger, everything starts falling apart. I feel like this is a fundamental difference to digital logic which is extremely easy to scale.

pfortuny3y ago

With 17 q-bits. Not something I’d call breathtaking.

aqme283y ago

It argues that QC is not currently viable. I don’t see an argument that it will never be viable, which is what “fundamentally unsound” means.

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