Bah! You know what I meant 
products of large primes 
I’m assuming the OP’s fantasy future fusion funtime, if DT, comes with a breeder blanket: Breeding blanket - Wikipedia
It’s hardly a solved problem. Hardly a tested problem, really. But ITER includes blanket studies. And DOE is actively funding tritium recovery and handling.
54 qbits is more than anyone else has gotten to work, so Google’s project is certain “supreme” in that sense. And it would enable the factoring of numbers as large as 2^54, in a small number of clock cycles. A single-processor classical computer, using straightforward classical algorithms, might take somewhere in the vicinity of a second to solve that problem. Depending on the clock speed of Google’s quantum computer, it might be able to do better than that, and so achieve “quantum supremacy” in that sense. But classical factoring algorithms parallelize very well (i.e., throwing ten or a hundred computers at the problem solves it ten or a hundred times faster), so there’s no reason to use a single-processor computer, and you could get a heck of a lot of processors for the cost of Google’s experimental device. And meanwhile, a 54-qbit computer can’t be used at all for factoring a 55-bit number, much less a thousand-bit one.
So, yeah, impressive progress, but still not actually practical.
It should also be mentioned, of course, that quantum computing is still a very new field. Programming a quantum computer isn’t just a matter of taking a classical program, and installing it on a different device. You need an entirely new algorithm, designed to take advantage of the specific advantages of a quantum computer, and finding those algorithms is the work of very smart people. It so happens that factoring is one of the problems for which we know of such an algorithm, and (due to encryption) it’s a potentially very important problem, but there are probably many other problems that we can solve better with quantum computers, and just don’t know it yet, because nobody’s come up with the algorithms yet.
Sure, but I’d also like to point out that the OP didn’t mention a timeline.
I mean, I could have talked about the current state of play with fusion, and how it’s unlikely to beat fission reactors (even, as you say, in terms of nuclear waste production) in the near future. But I think the OP is asking the question about why these concepts get hyped, and where they could eventually reach, so that’s the question I answered. I’m not talking about the next 30 years.
Also, I did allude to the fact that engineering difficulties, both known and unknown are likely to constrain how close we can get to the physical potential of fusion power.
But I deliberately didn’t talk about current reactors at all, because the point is, no current reactor comes close to being able to continuously and safely produce large amounts of power from fusion. So a hypothetical reactor with these properties is likely going to be significantly different in many ways.
It’s like if the OP was written in 1850 and was asking about how powered flight might change the world. I think it would be inappropriate to respond “Well, current attempts at flying machines involve bouncing a canvas parasol up and down, so we can conclude we will never be able to fly in the wind…”
OK, I’m being a little snarky now, but anyway, I’m just saying that I think we’re answering different interpretations of the OP.
With no time specified, I presume that the answer is ‘within the outer range of the expected lifespan of a human alive today’, which is in the neighborhood of 50-100 years. I don’t think that it’s sensible to interpret the question to mean “how could these technologies change the world ten million years in the future if a bunch of supporting magic technologies come along too”.
It would be inappropriate because that would be a wildly incorrect response based off of a gross lack of understanding of the technology available at the time. The first mechanically powered heavier than air flight was made in 1848 (incidentally, not by bouncing a parosol up and down), so concluding that it would be impossible would be amazingly stupid as it had already been done (though only for 30 feet and not carrying a human). The chief obstacles to flying a human for longer distances were the weight of materials strong enough to support the craft and the strength of engines, both of which were fields that were improving greatly decade to decade at the time.
That’s a fair paraphrasing is it?
I didn’t say anything beyond what a typical scientist or futurist might say when talking about the potential of fusion power. No magic, and no reason to think we’re talking more than the next few centuries.
It was obviously a joke meant to illustrate a point. I didn’t bother to check the year different kinds of flying machines were invented because it didn’t matter as I thought you’d get the point and we’d continue the discussion.
Instead you chose to ignore the actual point, and google the dates. Well, well done < golf clap >
Handling a massive amount of power delivered by neutrons in such a way that you don’t keep turning parts of your reactor into radioactive waste is an extremely difficult problem, and handwaving away that major issue with claims like ‘no dangerous waste’ is purely wishful thinking. As your own cite says, “To date, no large-scale breeding system has been attempted, and it is an open question whether such a system is possible to create. ITER runs a major effort in blanket design and will test a number of potential solutions.” So according to your own source, it’s not even clear that such a thing is possible, much less something that people are going to create in any time frame that the OP would see changing the world.
Also, you’re still going to need to mine lithium (and the ceramics to hold it in place, in the more likely designs) for the breeder blanket material. Lithium is not as universally abundant as hydrogen, so it still wouldn’t qualify as ‘unlimited fuel’ any more than uranium would, as you’re going to have to mine solid bodies for it. Even a breeder reactor couldn’t keep functioning on hydrogen alone.
If you’re not talking about some hypothetical far-future device that removes all of the practical issues, then clarify what you’re saying, because that certainly seemed to be what you were saying. This is GQ, so I’m trying to give the OP factual answers based on a reasonable interpretation of his question. In general, scientists are perfectly capable of stating things that are incorrect, exaggerated, or only true in a context which the person reporting what they omitted and ‘Futurists’ do it even more often. Repeating hyped up claims that aren’t true (or are true in a misleading sense) doesn’t help the person looking for a factual answer.
All of the varieties of fusion power that people are working on do produce dangerous waste, and do require significantly more materials than simple, readily available hydrogen to keep running. (Either a steady supply of tritium as a fuel, or lithium to keep breeding hydrogen). The claims of free, unlimited, clean energy aren’t based on anything realistically achievable.
Your joke was based on false information and failed to illustrate a relevant point. If you have a relevant point, you’d be better off clarifying what your point is than complaining that I didn’t sort out whatever it is that you’re trying to say.
An interesting point - the NSA (and no doubt, intelligence organizations of many countries) are hoovering up transmissions from all their competitors all over the world. Should someone produce a viable quantum computer capable of factoring large numbers to large primes, presumably suddenly everything private for many governments will suddenly become public knowledge… or will it? It’s not like your adversaries are going to tell you what they know. They may or may not have recorded your communications, they may or may not have decoded them.
Reminds me of the Russia House scenario - where the west is handed a document saying that Soviet missiles are horribly inaccurate, but no way to verify the leak. So what can you do except proceed with the worse case scenario just in case.
Of course it’s not clear. It’s not even clear that sustained fusion in a tokamak is possible; this is an “if only that were our biggest problem” kind of problem. While I’m not sanguine about anything practical anytime soon, the OP didn’t give us a time frame. My point is that for the current fantasy future being pursued, fission reactors are not a requirement for tritium, and nobody plans to have those 14 MeV neutrons wasted by just slamming into the superstructure.
The study has nothing to do with factoring.
As I said earlier, I assume a timeframe of ‘within a likely human lifespan’, so 50-100 years. I don’t think the OP is looking for ‘what might happen long after me and everyone I know is dead’, I think they’re looking for changes that might impact their own lives. Talking about purely speculative ideas that no one has started the engineering for and it isn’t clear that they’re even possible when the OP specifically asked for “no hype” doesn’t strike me as a reasonable approach - the ‘unlimited energy’ and ‘no dangerous waste’ claims clearly fall into the “hype” category.
The OP didn’t ask about fantasy, they asked how much these two technologies will act as “game changers” and “shake the world up”. I would take the “No hype” as explicitly asking for non-fantasy information, though it doesn’t literally say “no fantasy”. Fission reactors are currently a requirement for tritium, and there hasn’t even been a proof of concept of a practical tritium breeder fusion reactor, much less one that doesn’t leave the lithium blanket (or whatever is there to breed tritium) radioactive. People don’t want to let the neutrons slam into the superstructure, but they have to slam into something, and that something is almost certainly going to end up as the ‘dangerous waste’ that fusion hype says doesn’t exist.
The point is, there are different ways of interpreting the OP since it asks quite a broad question. I, and several others, have interpreted the question as just asking what the potential of nuclear fusion is…why do scientists get so excited about nuclear fusion, what benefits might it potentially have versus fission?
No specific timeline, no specific scenario. But certainly no magic.
You interpreted the OP as asking specifically about the near future. Fine. I didn’t say your interpretation is wrong, you are the one trying to tell everyone else they’re wrong.
Actually the explanation was right before the part you chose to quote, but anyway, I’ll repeat it and elaborate:
No fusion reactor right now comes close to safe and continuous energy production on a large scale. So, the one thing we know for sure about a hypothetical reactor that fulfills these requirements is that it is necessarily different from existing reactors in one or more ways.
So it’s pointless to talk about the limitations of existing reactors, except where those limitations are based on the laws of physics (in which case why even mention those reactors and not just talk about what is physically possible)?
If we had made commercial fusion power stations already but still had persistent engineering limitations then we have a basis to start to discuss whether those issues are solvable.
But we’re not there, we’re at the experimental stage, and it’s wrong to constrain a hypothetical mature technology to how current experiments function.
HMHW, Chronos,
Thanks for the detailed discussions. I won’t now claim to understand Quantum Computers, but I have a better mental image of the problem.
I assume that large number computations are handled as integers rather than floating point. So, the size of the integer is not limited by the architecture of the host computer. Why would the physical size of a Quantum computer impose a limit not experienced by current numerical computers?
The OP didn’t ask that. The OP stated that he had heard these two technologies will shake the world up, and asked how they will really change the world, and specifically asked for ‘no hype’. I am going to continue to call the idea that you can harness energy that’s 80% neutrons while generating and storing radioactive tritium without generating any ‘dangerous waste’ magic. Meanwhile “unlimited” is pure hype, especially when comparing to fission energy - there’s enough easily accessible uranium around to last for a few thousand years at least, and once extracting uranium from sea water is worked out (which is already done, it’s just not cost-effective so is much more realistic than tritium breeding in a fusion reactor, much less wasteless tritium breeding) you’re looking at hundreds of thousands to millions of years of fuel.
I think that presuming that the OP wants answers in the context of “more than a hundred thousand years from now” is a bit silly, but that’s the low end of the time frame where fusion is unlimited energy compared to fission.
It’s absolutely not pointless to talk about real-world issues when discussing how a given technology will shake up the world. Any likely implementation of fusion power will have to deal with those issues in some way, unless you just handwave them away with magic - which you claim not to be doing. “Well, we have no idea how to harness energy that’s 80% in energetic neutrons without having it irradiate some material, but there’s no physical law that says it’s completely impossible, therefore we should assume that fusion will shake up the world by some unknown process that we don’t even have a theoretical framework for how to make” is magical thinking. A process that we don’t have any idea how to do and no natural examples of is absolutely nothing like powered flight in 1850, where we had natural-world examples and small scale prototypes already working and the only difficulty was the need for realistic levels of light, strong materials and engine efficiency.
Practical fusion power generation is about 20 years in the future - just like 50 years ago, when practical fusion power was also only 20 years in the future.
The question is, given the current state of solar, wind, other renewables, and battery technology, plus the ability of computers to micromanage energy consumption by devices, how necessary is fusion power going to be?
It might become practical someday for giant industrial complexes like steel mills or smelters…
Most publications predict this to be in the 12 years to 100 years range. (Agree with the bulk of your post, though)
“ Various agencies have tried to estimate how long these primary resources will last, assuming a once-through cycle. The European Commission said in 2001 that at the current level of uranium consumption, known uranium resources would last 42 years. When added to military and secondary sources, the resources could be stretched to 72 years. Yet this rate of usage assumes that nuclear power continues to provide only a fraction of the world’s energy supply. If electric capacity were increased six-fold, then the 72-year supply would last just 12 years.[60] The world’s present measured resources of uranium, economically recoverable at a price of US$130/kg according to the industry groups Organisation for Economic Co-operation and Development(OECD), Nuclear Energy Agency (NEA) and International Atomic Energy Agency (IAEA), are enough to last for “at least a century” at current consumption rates.[61][62] According to the World Nuclear Association, yet another industry group, assuming the world’s current rate of consumption at 66,500 tonnes of uranium per year and the world’s present measured resources of uranium (4.7–5.5 Mt[61]) are enough to last for some 70–80 years.[63]”
So, the size of the integer is not limited by the architecture of the host computer. Why would the physical size of a Quantum computer impose a limit not experienced by current numerical computers?
Firstly, that’s only true for a specific set of problems. There is another set of problems where limiting the size of the integer to the architectural limit is very important. Normal encryption problems occupy a special space: they are very large bit size problems that have been specifically designed to work in small bit size architectures. But cracking isn’t something they have been designed to optimize.
Secondly, for the kind of problem where quantum computers are proposed, the computer is fundamentally different. Sure, you could use a quantum computer to simulate a current numerical computer, but that’s not what people want. It’s like (and unlike) the difference between an analog computer and a digital computer.
People want to use quantum computers to simulate nuclear fusion directly. To do that, you want to have a quantum computer that maps to the nuclear fusion you are simulating. The bigger the computer, the bigger the simulation. At present, you could take a digital computer to map to the simulation, but it would still be fundamentally different: you have to calculate the simulation state. A quantum computer wouldn’t “calculate” the simulation state: it would “exist” the simulation state.
At current consumption rates, using traditional thermal neutron reactors, and sourcing from conventional, high-concentration surface sources.
Breeders ain’t cheap, but are more realistic than, say, seawater extraction. Although there have been advances there.
Thanks for the response. That makes sense.
It seems that the Quantum Computer is an analog computer. Whatever the mysterious internal workings of a Quantum Computer may be, a user would have to set up initial conditions - provide an input. It is my experience that setting up initial conditions in analog computers was much more complicated than doing the same thing in digital computers. Can you describe the mechanics of a minimum input?