Quantum computing's reality check

The big unsolved problem in QC is the lifetime of the QC itself until decoherence. Imagine a computer where you can execute a maximum of 1800 commands (IBM Heron) and then it is broken. That is the status of QC at the moment. A QC might store TB of data and do searches with O(1), but there is no way (at the moment) to upload a TB database to the QC. What we need is a quantum processor that lives for hours or days in a coherent state, but what we have is milli seconds.<p>Just my 2 ct.<p>edit: IBMs Roadmap shows a QC with 1 Billion commands (gates) after 2033. With that machine they could (in principle) upload a 100MB database and do searches.<p>source: <a href="https:&#x2F;&#x2F;www.tomshardware.com&#x2F;tech-industry&#x2F;quantum-computing&#x2F;ibm-demonstrates-useful-quantum-computing-within-133-qubit-heron-announces-entry-into-quantum-centric-supercomputing-era" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.tomshardware.com&#x2F;tech-industry&#x2F;quantum-computing...</a>

The roadmap of IONQ has them producing 64 logical qubits with error correction within 2025. Whether or not they succeed, I think time will tell as theyve stopped publishing and a cofounder stepped down to return to teaching and research.<p>Quantinuum, the Honeywell merger, expects billions of revenue in 2026. Honeywell gave up on transmons and joined up with their $260m investment into Cambridge.<p>Speaking of transmons, Rigetti is facing delisting<p>IBM is still going hard on transmons and selling mainly to universities.<p>Google had sycamore but were still waiting to see if they’ve solved the cascading errors inherent to scaling<p>Microsoft invested heavily in majorna fermions for compute — which might not even exist. They are not an authority on the physics

I don&#x27;t think its just skeptics. Afaik most researchers (other than those who are trying to attract investments) have been very clear that we are still a ways off from practical quantum computing, and even then the applications of QC is limited to specific domains.

General purpose QC isn&#x27;t going to happen all that soon, and may always be faced with scaling issues.<p>But we <i>will</i> see QC in a very specific application before the decade is out.<p>It&#x27;s kind of a perfect marriage between ML and QC. If you want stochastic outputs and aren&#x27;t going to know what&#x27;s going on at each step in the network anyways, the issues of error correction around measurement aren&#x27;t nearly as crippling as they are for general purpose QC.<p>While initially the work will be converting from classical to optoelectronic hardware for matching current operations, such as MIT&#x27;s work this year, once we&#x27;ve seen greater availability of optoelectronic hardware I suspect we&#x27;ll see algorithms for ML developed that would only work in photonic networks and fully exploit the quantum properties therein.

I got curious about quantum computers so I ordered and read (most of) Quantum Computation and Quantum Information: 10th Anniversary Edition.<p>It pretty much proved to me that quantum computing is at best 100+ years away or at worst a pipe dream fantasy. Until decoherence at scale is solved there is no way quantum computing will be useful beyond current computing abilities. There is not even a hint that this problem will be solved anytime soon.

For all the people saying this is a scam&#x2F;waste of money&#x2F;always 10 years away, I’m curious what you envision the funding model for this kind of speculative tech to be. The government ceased to be the bankroll for this kind of stuff since the end of the Cold War, and for better or for worse, VC is where the money is right now. The marketing BS with stuff like quantum, fusion, carbon capture, etc. is simply a cost of doing business in this environment.<p>If it’s such a travesty that VCs are making bets on tech like this, how then do you fund long term R&amp;D projects with a high risk of failure? Isn’t that the point?

Moore&#x27;s law was enabled by lithography which enabled a pretty clear path forward on how to shrink transistors over time. AFAIK there is no similar enabling technology for qubit. Maybe that will change, but until then, I don&#x27;t really see much hope for quantum computers future.

Prescient article: <a href="https:&#x2F;&#x2F;scottlocklin.wordpress.com&#x2F;2019&#x2F;01&#x2F;15&#x2F;quantum-computing-as-a-field-is-obvious-bullshit&#x2F;" rel="nofollow noreferrer">https:&#x2F;&#x2F;scottlocklin.wordpress.com&#x2F;2019&#x2F;01&#x2F;15&#x2F;quantum-comput...</a>

What is happening with QC is very sad.<p>Research on this topic should be a long term scientific endeavor, like nuclear fusion has been for many years.<p>Not the circus it has been so far.

I&#x27;m yet to see a single business case of money entering the QC value chain outside of (a) other QC businesses and (b) moonshot investments.<p>After ~15 years of literally the world&#x27;s smartest people trying to come up with exactly that (some of which are dear friends), the only way conscionable way I can regard QC is as a vapor bubble.

The fact that a working quantum computer exists and works at all is mind blowing to me.

Ever since I understood how quantum computers actually work, I’ve been a skeptic.

I was recently learning about Shors Algorithm which was kind of mind blowing until I found out it can’t actually be executed on anything right now. We’re still in the super early days. Like where microcomputers were 40-50 years ago

Can some explain me, since I don’t know, but I have this idea that ideally quantum computer is like artificial neural network hardware which can change its connections in realtime.<p>I just cannot help seeing how cubits are very much like probabilities comes out from ML, something between 0..1.<p>I’m I completely lost here? I’m curious to understand better:)<p>PS. Is it possible that brain is organic quantum computer?<p>Also. Do you see it possible that our senses and awareness are “prompting” the models we have built during life and thoughts are what comes back from the prompts?

I&#x27;m pretty certain the QC development will continue even if at a slightly slower rate. And maybe AI can help with manufacturing more reliable and cheap versions :-) What I think has not be investigated so much is what can be done with a not so reliable quantum computer? At the start of computers Colossus was not ultra reliable but that didn&#x27;t matter as it just cycled around trying different possibilitied on codes so failing on the task every so often wouldn&#x27;t have made much difference.

One of the big challenges is being able to frame real world concrete problems in terms that are solvable by quantum algorithms. There are a shocking lack of examples out there.<p>Even when the hardware is there, it isn’t clear how quantum computing can do useful things. But I suspect this is a solvable problem of good communications. But right now, experts in quantum don’t seem to be able to provide these examples. Or they don’t exist.

Quantum computing is definitely overhyped right now. In my eyes, I don&#x27;t see how this fundementally changes computing. AI, for example, literally lets you do things that weren&#x27;t possible before. This just lets you store more data and manipulate it faster. It&#x27;s not a shift in the core framework of the technology.

Quantum Computers: A Brief Assessment of Progress in the Past Decade<p><a href="https:&#x2F;&#x2F;gilkalai.wordpress.com&#x2F;2022&#x2F;05&#x2F;26&#x2F;waging-war-on-quantum&#x2F;" rel="nofollow noreferrer">https:&#x2F;&#x2F;gilkalai.wordpress.com&#x2F;2022&#x2F;05&#x2F;26&#x2F;waging-war-on-quan...</a>

Like Bletchley Park during the last world war, the best-case scenario for intelligence is that the government has quantum computers that break public-key encryption and nobody finds out. It’s hard to know what machines exist behind the scenes.

Quantum winter? Maybe OpenQuantum will do some amazing stuff off a Google paper in 20 years time?

Fool’s gold.<p>QC is the Alchemy of our times.<p>Just like room-temperature superconductivity is the perpetual motion of our time…

Skepticism of digital computing was a pretty open-air phenomena too.<p>Specialization and generalization of hardware is also cyclical same as centralized and decentralized services.

It won&#x27;t work. It&#x27;s just another tech scam that will fail, but at least we got great research out of it.