[HN Gopher] FAQ on Microsoft's topological qubit thing
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FAQ on Microsoft's topological qubit thing
Author : ingve
Score : 295 points
Date : 2025-02-20 07:25 UTC (15 hours ago)
(HTM) web link (scottaaronson.blog)
(TXT) w3m dump (scottaaronson.blog)
| ABS wrote:
| money quote: "if Microsoft's claim stands, then
| topological qubits have finally reached some sort of parity with
| where more traditional qubits were 20-30 years ago. I.e., the
| non-topological approaches like superconducting, trapped-ion, and
| neutral-atom have an absolutely massive head start: there,
| Google, IBM, Quantinuum, QuEra, and other companies now routinely
| do experiments with dozens or even hundreds of entangled qubits,
| and thousands of two-qubit gates. Topological qubits can win if,
| and only if, they turn out to be so much more reliable that they
| leapfrog the earlier approaches--sort of like the transistor did
| to the vacuum tube and electromechanical relay. Whether that will
| happen is still an open question, to put it extremely mildly."
| tromp wrote:
| The quote that struck me was
|
| > I foresee exciting times ahead, provided we still have a
| functioning civilization in which to enjoy them.
| gauge_field wrote:
| If you are shocked by this, I suggest not reading his other
| recent topics.
| moshun wrote:
| Spent an hour going through his blog. Wild and unpleasant
| ride.
| darknavi wrote:
| The comments section of that blog is truly a wild ride.
| fc417fc802 wrote:
| As it should be.
|
| > For most of my professional life, this blog has been my
| forum, where anyone in the world could show up to raise
| any issue they wanted, as if we were tunic-wearing
| philosophers in the Athenian agora.
|
| https://scottaaronson.blog/?p=6576
| tdb7893 wrote:
| It's interesting to see someone who seems to describe
| themself as anti-woke try desperately to convince the
| generally anti-academic movement to fund academics. Sadly
| I don't think he'll succeed in this.
|
| I don't agree with many of his posts but I think the blog
| is interesting in how personal it feels. Often I feel
| like all media is very cultivated but he seems very
| willing to put his own anxieties and foibles on the web.
| KerrAvon wrote:
| FWIW, it's unclear how the NSF ends up. Musk needs
| scientists to make rockets go. The defense industry needs
| a broad spectrum of scientists to make all kinds of
| things happen. Scientists (and especially the schools
| producing said scientists) need funding to operate, or
| there will no longer be accredited scientists.
|
| Does Musk understand this? Maybe not. It's not evident so
| far. He certainly lives in a fictional world of the right
| wing's devising. Will someone else be able to penetrate
| that bubble to make him understand it? Will he care if
| they do? Guess we'll find out.
| HappyPanacea wrote:
| I found his blog to be candid and well thought out
| usually
| echelon wrote:
| > If you are shocked by this, I suggest not reading his
| other recent topics.
|
| Given that this is Scott Aaronson, does he suggest we'll
| break cryptography and destroy the foundations of the
| modern internet?
| vonneumannstan wrote:
| AI takeover is what he's referencing.
| ameliaquining wrote:
| Also distress at various political developments.
| fauigerzigerk wrote:
| There seems to be a bit of a disconnect between the first and
| the second sentence (to my completely uneducated mind).
|
| _If_ topological qubits turn out to be so much more reliable
| then it doesn 't really matter how much time was spent trying
| to make other types of qubits more reliable. It's not really a
| head start, is it?
|
| Or are there other problems besides preventing unwanted
| decoherence that might take that much time to solve?
| tsimionescu wrote:
| The point I think is this: if topological qubits are similar
| to other types of qubits, then investing in them is going to
| be disappointing because the other approaches have so much
| more work put into them.
|
| So, he is saying that this approach will only pay off if
| topological qubits are a fundamentally better approach than
| the others being tried. If they turn out to be, say, merely
| twice as good as trapped ion qubits, they'll still only get
| to the achievements of current trapped ion designs with
| another, say, 10-15 years of continued investment.
| adastra22 wrote:
| The whole point though is that they are step function
| better than traditional qubits, in a way that is simply a
| type error to compare.
|
| The utility of traditional qubits depends entirely on how
| reliable and long-lived they are, and how to can scale to
| larger numbers of qubits. These topological qubits are
| effectively 100% reliable, infinite duration, and scale
| like semiconductors. According to the marketing literature,
| at least...
| pclmulqdq wrote:
| All the other qubits scaled the same way when they were
| in a simulator, too. When they actually hit reality, they
| all had huge problems.
| adastra22 wrote:
| Other qubits in general do not scale the same way. Some
| for example do not allow arbitrary point-to-point
| interactions, which means doubling your physical qubits
| doesn't double your number of logical qubits. There are
| other ways in which scaling was sometimes nonlinear.
|
| Note also that this isn't a simulated result. Microsoft
| has an 8-qubit chip they are making available on Azure.
| pclmulqdq wrote:
| I am well aware of how other qubits scale, but I am also
| aware that the physicists who created them didn't expect
| decoherence to scale this rapidly at the time they took
| that approach.
|
| IBM sells you 400 qubits with huge coherence problems.
| When IBM had an 8-qubit chip, they were also pretty
| stable.
| radioactivist wrote:
| There are caveats there too. Generally topological qubits
| _can_ be immune to all kinds of noise (i.e. built-in
| error correction) but Majorana zero modes aren 't exact
| the right kind of topological for that to be true. They
| only enjoy protection on most operations, but not all. So
| there is a still a need for error correction here (and
| all the complication that entails) it is just hopefully
| less onerous since only essentially one operation
| requires it.
| nprateem wrote:
| Yeah I mean that's exactly what MS are talking about, only
| requiring 1/20 of the checksum qubits or something.
|
| https://www.ft.com/content/a60f44f5-81ca-4e66-8193-64c956b09...
| ABS wrote:
| what Microsoft claim in their marketing copy reported by the
| FT - for the average reader - and what a third-party, well-
| known expert in the field thinks... are on very different
| levels AFAIC
|
| Microsoft is saying: we did it!
|
| Everyone else is saying: prove it!
| nprateem wrote:
| Yes, that's why we read decent journalism that includes the
| opinions of experts. MS are still saying production use is
| pretty far off.
| ABS wrote:
| except we don't need opinions, we need proof and that is
| what we are lacking.
|
| The only expert in the FT article is Dr. Sankar Das Sarma
| who (from Wikipedia) "In collaboration
| with Chetan Nayak and Michael Freedman of Microsoft
| Research, Das Sarma introduced the n = 5 / 2 topological
| qubit in 2005"
|
| So you might understand why this FT article is not adding
| anything to the discussion, which does not discuss the
| theory but rather MS's claim of an actual breakthrough.
|
| They show a chip, we'd like proof of what the chip
| actually does
| ggm wrote:
| I enjoy the quality of "it's too early to say" in Aaronson's
| writing. It won't stop share price movement or hopeless optimism
| amongst others.
|
| I do wonder if he is running a simple 1st order differential on
| his own beliefs. He certainly has the chops here, and self
| introspection on the trajectory of highs and lows and the trends
| would interest me.
| blablabla123 wrote:
| This seems quite a bold claim that Microsoft proofed that
| Neutrinos are Majorana particles...
| eigenspace wrote:
| Huh? This has nothing to do with neutrinos.
| blablabla123 wrote:
| The chip is literally called Microsoft Majorana 1
|
| Indeed Majorana fermions are completely unseen/unconsidered
| outside of Neutrinos. In fact all Standard Model fermions
| except Neutrinos are proven to be Dirac fermions
| eigenket wrote:
| The Majorana particles in Microsoft's set-up are "quasi-
| particles". They aren't really fundamental particles, but
| excitations in the system which behave (roughly, in some
| appropriate sense) like particles. They aren't neutrinos.
| blablabla123 wrote:
| Quite confusing though
|
| > "There's no slam dunk to know immediately from the
| experiment" that the qubits are made of topological
| states, says Simon. (A claim of having created Majorana
| states made by a Microsoft-funded team based in Delft,
| The Netherlands, was retracted in 2021.) The ultimate
| proof will come if the devices perform as expected once
| they are scaled up, he adds.
|
| https://www.nature.com/articles/d41586-025-00527-z
| eigenket wrote:
| I'm not sure what that has to do with my previous comment
| but yeah, pushing the boundaries of science is kinda
| difficult and you can make mistakes.
|
| My understanding is that they pretty convincingly showed
| that the thing they built acts as a qubit. This means
| that if its not doing what they think its doing (the
| "topological" / Majorana stuff) then they accidentally
| made a qubit which works some other way. That isn't
| outside the realm of possibility but it is fairly
| unlikely.
| terminalbraid wrote:
| You are confusing quasiparticles with fundamental
| particles. If we were to observe a Majorana topological
| state, this would have no bearing on the properties of the
| neutrino.
|
| Also to say Majorana fermions are not considered outside of
| neutrinos is a patently ridiculous and ignorant statement.
| There is absolutely nothing in physics to say the only
| particle that can possibly be Majorana is a neutrino. For
| example, there have been theories of Majorana dark matter
| _which are a consideration of fundamental Majorana
| particles outside of neutrinos_.
| dang wrote:
| Recent and related:
|
| _Microsoft unveils Majorana 1 quantum processor_ -
| https://news.ycombinator.com/item?id=43104071 - Feb 2025 (150
| comments)
| librasteve wrote:
| topological analytics shows that under like-like exchanges
| multiple distinct pathways exist in 2D (in 3D topology does not
| have distinct pathways for these exchanges). this permits real
| anyon particles to exist when the physics is confined to 2D
| within quantum limits such as in a layer of graphene. certain
| configurations of layers ("moire materials") can be made periodic
| to provide a suitable scale lattice for anyons to localize and
| adopt particular quantum states
|
| anyons lie somewhere between fermions and bosons in their state
| occupancy and statistics - no 2 fermions may occupy the same
| state, bosons can all occupy the same state, anyons follow
| rational number patterns eg up to 2 anyons can occupy 3 states
| jokoon wrote:
| I wonder if this means that ai will have more capabilities with
| quantum computing.
|
| So far, I haven't read how those chips are programmed, but it
| seems like it requires to re learn almost everything.
|
| I don't even know if there is an OS for those.
| eigenket wrote:
| There is not an "OS" or anything even remotely like it. For now
| these things behave more like physics experiments than
| computers.
|
| You can play around with "quantum programming" through (e.g.)
| some of IBM's offerings and there has been work on quantum
| programming languages like q# from Microsoft but its unclear
| (to me) how useful these are.
| ABS wrote:
| that's not the way to think about quantum computing AFAIK.
|
| Think of these as accelerators you use to run some specific
| algorithm the result of which your "normal" application uses.
|
| More akin to GPUs: your "normal" applications running on
| "normal" CPUs offload some specific computation to the GPU and
| then use the result.
| tsimionescu wrote:
| So far, the only known algorithm relevant to AI that would run
| faster on a theoretical quantum computer is linear search,
| where quantum computers offer a modest speedup (linear search
| is O(n) on a classical computer, while Grover's algorithm is
| O(sqrt(n)) for quantum computers - this means that for a list
| of a million elements, you can scan it in 1 000 steps on a
| quantum computer instead of 1 000 000 steps on a classical
| one).
|
| However, even this is extremely theoretical at this time - no
| quantum computer built so far can execute Grover's algorithm,
| they are not reliable enough to get any result with probability
| higher than noise, and anyway can't apply the amount of steps
| required for even a single pass without losing entanglement. So
| we are still very very very far away from a quantum computer
| that could reach anything like the computing performance of a
| single consumer-grade GPU. We're actually very far away from a
| quantum computer that even reaches the performance of a hand
| calculator at this time.
| cognaitiv wrote:
| https://en.wikipedia.org/wiki/Quantum_optimization_algorithm.
| ..
| cognaitiv wrote:
| Pure Quantum Gradient Descent Algorithm and Full Quantum
| Variational Eigensolver https://arxiv.org/abs/2305.04198
| JPLeRouzic wrote:
| > " _an OS for those_ "
|
| Or at least an OS driver for the devices supporting quantum
| computing if/when they become more standard.
| K0balt wrote:
| I think what many people are missing in the discussion here is
| that topological qbits are essentially a different type of
| component. This is analogous to relay-triode-transistor
| technology progression.
|
| It is speculation still whether the top-q approach will be
| effective, but there are significant implications if it is.
| Scalability, reliability, and speed are all significant aspects
| on the table here.
|
| While other technologies have a significant head start, much of
| the "head start" is transferrable knowledge, similar to the
| relay-triode-transistor-integrated circuit progression. Each new
| component type multiplies the effectiveness of the advances made
| by the previous generation of technologies, it doesn't start
| over.
|
| IF the topological qubits can be made to be reliable and they
| live up to their scalability promises, it COULD be a
| revolutionary step, enabling exponential gains in cost,
| scalability, and capability. IF.
| eliovi wrote:
| A bit off topic - I really like Scott Aaronson and his blog, but
| hate the comment section - he engages a lot with the comments
| (which is great!) but it's really hard to follow, as each comment
| is presented as a new message.
|
| I made this small silly chrome extension to re-structure the
| comments to a more readable format - if anyone is interested
|
| https://github.com/eliovi/shtetl-comment-optimized
| throw_pm23 wrote:
| I find the opposite, he often makes some ridiculous claim in
| the post, the comments (the ones he lets through) rightfully
| point out how wrong he was, then he cherry-picks and engages
| one of the more outrageous comments, so a superficial observer
| is left with the impression that the original claim was OK.
| api wrote:
| I had a thought while reading this:
|
| Are we, in fact, in the very early stages of gradient descent
| toward what I want to call "software defined matter?"
|
| If we're learning to make programmable quantum physics
| experiments and use them to do work, what is that the _very
| beginning_ of? Imagine, say, 300 years from now.
| pyinstallwoes wrote:
| TVs : displays already are software defined matter. But ya.
| pyinstallwoes wrote:
| Hey anyons 2D electron gas. Wrote about it a while ago and get
| downvoted!
| mehulashah wrote:
| We should celebrate this for what it is: another brick in the
| wall that we're building to achieve practical quantum computing
| systems.
| throw_pm23 wrote:
| Yes, just like putting two bricks onto each other is a first
| step to the moon.
| ameliaquining wrote:
| That's the best-case scenario. It remains possible that
| topological qubits, even if they are theoretically achievable,
| will turn out to be a dead end engineeringwise. Presumably
| competing quantum computing labs think this is likely, since
| they're not working on topological qubits; only Microsoft
| thinks they'll end up being important.
| tim333 wrote:
| I remain curious if you can actually calculate anything with
| these gadgets? I mean can it add 2 and 2 or work out the factors
| of 30 or anything?
| advisedwang wrote:
| This experiment only created one qubit, so no.
|
| The experiment with lots of qubits... technically yes they can
| do things. I think the factoring record is 21. But you might be
| disappointed a) when you see that most algorithms using quantum
| computers require conventional computational to transform the
| problem before and after the quantum steps b) when you learn we
| only have a few quantum algorithms, the are not general
| calculation machines and c) when you look under the hood and
| see that the error correcting stuff makes it actually kinda
| hard to tell how much is really being done by the actual
| quantum device.
| tim333 wrote:
| Thanks for the reply. I've always been a bit puzzled from my
| limited knowledge of quantum mechanics as to how they are
| supposed to work. I mean you make a measurement on a quantum
| system and sure the probability amplitude is the result of
| adding up all sorts of possible paths but you still only get
| the one measurement out which I'm not sure how that's
| supposed to tell you much. All a bit beyond me.
| jiacobucci00 wrote:
| you typically have to sample multiple times until you can
| build up the distribution that you can convert to a
| solution to your problem.
| ameliaquining wrote:
| Does https://scottaaronson.blog/?p=208 help?
|
| (Also, the factoring-21 result is from 2012, and may have
| been surpassed since then depending on how you count.
| Recent quantum-computing research has focused less on
| factoring numbers and more on problems like random circuit
| sampling where it's easier to get meaningful results with
| the noisy intermediate-scale machines we have today.
| Factoring is hard mode because you have to get it exactly
| right or else it's no good at all.)
| strangeloops85 wrote:
| A very important statement is in the peer review file that
| everyone should read:
|
| "The editorial team wishes to point out that the results in this
| manuscript do not represent evidence for the presence of Majorana
| zero modes in the reported devices. The work is published for
| introducing a device architecture that might enable fusion
| experiments using future Majorana zero modes."
|
| https://static-content.springer.com/esm/art%3A10.1038%2Fs415...
| throw_pm23 wrote:
| Another recent writeup that adds some nuance to this (and other
| claims), summarizing the quantum-skeptic positions:
|
| https://gilkalai.wordpress.com/2025/02/17/robert-alicki-mich...
| ameliaquining wrote:
| I think that Kalai here is very seriously understating how
| fringe/contrarian his views are. He's not merely stating that
| there's too much optimism about potential future results, or
| that there's some kind of intractable theoretical or
| practical bottleneck that we'll soon reach and won't be able
| to overcome. He's saying that _any_ kind of quantum advantage
| --a thing that numerous experiments, from different labs in
| academia and industry, using a wide variety of approaches,
| have demonstrated over the past decade--is impossible, and
| therefore all of those experimental results were wrong and
| need to be retracted. His position was scientifically
| respectable back when the possibility he was denying _hadn 't
| actually happened yet_, but I don't think it is anymore.
| gsf_emergency_2 wrote:
| As the recent results from CS and math on the front pages have
| shown, one doesn't have to be unknown or underfunded in order
| to produce verifiable breakthroughs, but it might help..
|
| Seems like John Baez didn't notice those lines in the peer
| review either
|
| https://mathstodon.xyz/@johncarlosbaez/114031919391285877
|
| TIL: read the peer review first
| samr71 wrote:
| Wait so this tech just...doesn't work yet? Like at all?
| throw_pm23 wrote:
| It's worse, it will (likely) never work at all.
| ameliaquining wrote:
| Microsoft claims that it works. However, the Nature reviewers
| apparently do not yet feel comfortable vouching for this
| claim.
| samr71 wrote:
| Other than fast factorization and linear search, is there
| anything that Quantum Computing can do? Those do seem important,
| but limited in scope - is this a solution in search of a problem?
|
| I've heard it could get us very accurate high-detail physics
| simulations, which has potential, but don't know if that's legit
| or marketing BS.
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