But that's just the thing. The intrinsic mechanisms involved suggest precisely otherwise.

Fusion requires a huge amount of energy to drive the deuterium together to form helium. This is NOT a chain reaction! The process demands a continuous "push" in order to keep things going.

Fission on the other hand is does NOT require sustained energy input. The ejected neutrons from the very first reaction lead to even more reactions and so forth. It is an unstable system and the reaction is easily initiated by external forces.

So if there is any use for fusion it must be for some utilitarian purpose. Because it can NEVER generate excess energy. It's the atomic analogue of an endothermic reaction. (And fission could thus be correspondingly categorized as "exothermic".)

Well the physics was supposedly proved already.

Aside from that, it sounds like you are saying that a large number of scientists who must know what they are doing are working on something that will never work and they arent stupid so they must know this already. Can you really believe that?

It's ok if you do i guess, i believe you have that right, but then all i can say is we all have our inner thoughts and beliefs we deal with every day, and all people do not think the same way and believe the same things. We have to accept that first anyway as we are not the grand deciders of the universe nor anything close to that
So in the end i have to accept your viewpoint as a possibility but i will grade it according to what i have already learned and assign some probability as to the truth of that viewpoint and i do the same with my own personal viewpoint. My own viewpoint is going to have a higher probability of being true, but that's just the way we all are in most cases where we have a lot of knowledge on the subject and believe that is sufficient to make a good judgement. Any of us can be wrong there's no way around that.

 

The bottom line is will it be possible to make money with fusion energy. Even if it all works as planned it just might not be competitive with that fusion generator in the sky for a long time.

Yeah it is sad that we havent done this and completed this yet. There are alternatives in fission that still remain to be seen as well and that may take us forward for the short term if not longer.
Using other elements i read that fission can be made safer and there are two approaches being thought about and i guess tested or eventually tested using two different elements. One has a half life of 12 or so years and i think the other is shorter about 2.5 years or something but may be as short as 15 hours. I will admit though i havent read that much on these technologies yet. Compared to uranium the half life is between 25 thousand years and 4.5 billion years depending on what type it is, but even 25k is way too long much longer than all recorded history.

One way or another we have to put an end to the Fukushima shuffle. There are significantly mutated plant life 100 miles from the site.

 

Well the physics was supposedly proved already.

Aside from that, it sounds like you are saying that a large number of scientists who must know what they are doing are working on something that will never work and they arent stupid so they must know this already. Can you really believe that?

It's ok if you do i guess, i believe you have that right, but then all i can say is we all have our inner thoughts and beliefs we deal with every day, and all people do not think the same way and believe the same things. We have to accept that first anyway as we are not the grand deciders of the universe nor anything close to that
So in the end i have to accept your viewpoint as a possibility but i will grade it according to what i have already learned and assign some probability as to the truth of that viewpoint and i do the same with my own personal viewpoint. My own viewpoint is going to have a higher probability of being true, but that's just the way we all are in most cases where we have a lot of knowledge on the subject and believe that is sufficient to make a good judgement. Any of us can be wrong there's no way around that.

Very well said. If what he believes is true then this moment in history should have never happened.
https://www.atomicarchive.com/history/hydrogen-bomb/page-13.html

https://physics.info/weapons/practice.shtml

All these processes, proceeding through microseconds, prepared Mike for thermonuclear burning. Now the escaping X-radiation of the fissioning sparkplug heated the compressed deuterium at its boundaries; the increasing thermal motion of the deuterium nuclei pushed them together until they passed the barrier of electrostatic repulsion between them and came within range of the nuclear strong force, at which point they began to fuse. Some fused to form a helium nucleus — an alpha particle — with the release of a neutron, the alpha and the neutron sharing an energy of 3.27 MeV(1). The neutron passed through the electrified mass of fusing deuterons and escaped, but the positively charged alpha dumped its energy into the heating deuterium mass and helped heat it further.

Other deuterium nuclei fused to form a tritium nucleus with the release of a proton, the triton and the proton sharing 4.03 MeV(2). The positively charged proton dumped more energy into the deuterium mass. The tritium nucleus fused in turn with another deuterium nucleus to form an alpha particle and a high-energy neutron that shared 17.59 MeV(3). The 14 MeV neutrons from this reaction began to escape the hot, compressed deuterium plasma and encountered the U238 nuclei of the vaporized uranium pusher. U238 fissions when it captures neutrons with energies above 1 MeV; so the U238 of the uranium pusher began to fission then under the intense neutron bombardment, flooding more X rays back into the deuterium mass from the outside just as the sparkplug fission reaction was radiating them from the inside, trapping the deuterium between two violent walls of heat and pressure. Deuterium-bred tritium fused with tritium as well, producing a helium nucleus and two neutrons that shared 11.27 MeV of energy(4). At lower orders of probability, deuterium captured a neutron and bred tritium(5); deuterium-bred helium fused with deuterium and made heavy [ordinary] helium plus a highly energetic proton(6), or captured a neutron and bred tritium plus a proton(7). All these reactions contributed to the force of the Mike explosion.

 

Sorry that doesn't apply here. The pressures and temperatures obtained by the fission process in that case just happened to be sufficient enough to drive the fusion reaction (for a second or so at least).

What I am talking about is a truly self-sustaining fusion reaction that generates more energy than it consumes. And as I said before that is simply not possible. You will NEVER be able to pull the plug on such a machine and expect it to keep going without those EXTREME external forces being applied continuously.

Look I've been saying for almost thirty years now that this isn't possible and I have yet to be proven wrong! If the theories supporting this idea are so compelling then pray tell why hasn't ANYONE been able to put together even the crudest "proof of concept" device?

The real reason we keep hearing about things like quantum computing and fusion energy is quite simply that they just happen to be areas of research which tend to garner a LOT of funding. Science departments are ever in need of CASH FLOW. Unfortunately that sometimes means researching things that may not be very viable but nonetheless might be useful for securing future funding. And that is precisely why we keep hearing scientists hawking these same old "pie in the sky" ideas day after day, year after year. Got to pay those bills man!

 

We disagree about the fundamentals of fusion energy production possibilities but even if we don't have a truly self-sustaining fusion reaction in the near-term we fundamentally can still have a fusion Q total of more than 1 (pull the plug) if our Q plasma is high.
My pessimism of fusion is based on the classic of, "What's possible is not always practical" not a misunderstanding of high-school physics.

At the nuclear level it's more like burning a hydrocarbon fuel, a sustained burn is nice (turbine) but it's not really necessary for positive power generation. We easily get more energy out than in with a diesel engine when we create the correct conditions for pulsed ignition. We don't even need electrical power on my ship, we could start diesel engines with compressed air in an emergency.
https://www.nuclear-power.com/nucle...l-engine/thermal-efficiency-for-diesel-cycle/

 

Things like nuclear fission and petroleum these system contain a whole lot of "pent up" energy, much like a highly compressed spring.

Fusion on the other hand is more like the problem of combusting water. You can indeed burn the latter and obtain a self-sustaining reaction. However in order to do so you must FIRST unburn it.

Likewise the precursors for fusion are also in their lowest state. You can get it to fuse, but not for free! It will always require more energy simply due to the law of conservation of energy. You have to force each and every one of those hydrogen atoms together EVERY SINGLE TIME!

Again fission does not have any such requirement. Like petroleum it only requires some kind of "spark" to get things going.

 

Sorry that doesn't apply here. The pressures and temperatures obtained by the fission process in that case just happened to be sufficient enough to drive the fusion reaction (for a second or so at least).

What I am talking about is a truly self-sustaining fusion reaction that generates more energy than it consumes. And as I said before that is simply not possible. You will NEVER be able to pull the plug on such a machine and expect it to keep going without those EXTREME external forces being applied continuously.

Look I've been saying for almost thirty years now that this isn't possible and I have yet to be proven wrong! If the theories supporting this idea are so compelling then pray tell why hasn't ANYONE been able to put together even the crudest "proof of concept" device?

The real reason we keep hearing about things like quantum computing and fusion energy is quite simply that they just happen to be areas of research which tend to garner a LOT of funding. Science departments are ever in need of CASH FLOW. Unfortunately that sometimes means researching things that may not be very viable but nonetheless might be useful for securing future funding. And that is precisely why we keep hearing scientists hawking these same old "pie in the sky" ideas day after day, year after year. Got to pay those bills man!

I was under the impression that the requirement was a certain temperature threshold, which has now been reached. Maybe that is why they say it will work now.

But we have a good example right up in the sky every day: the Sun.

 

It will always require more energy simply due to the law of conservation of energy.

There's an amount of energy required to fuse hydrogen nuclei, and there's an amount of energy released from the same reaction. From some initial research, it takes temperatures of about 100 million K to fuse hydrogen nuclei (to overcome Coulomb repulsion). Converting this to electron volts (\(100\cdot10^6k_B/e\)) give us 8.6 keV per reaction.
The amount of energy released by fusing 4 hydrogen nuclei to create a couple helium and energy, you release 26.7 MeV (due to binding energies and mass-energy conversion).
So 17.2 keV to start the reaction and 26.7 MeV output.
Or, in other words, a single (uncontrolled) reaction has an output/input ratio of 1552.
So, no: the energy it takes to get the process started is NOT more energy than you get out.
If it worked the way you think it works, we'd never have been able to build the fusion (hydrogen) bomb, which is the point @nsaspook was making.

The problem facing scientists at the moment with fusion is figuring out how to start it, contain it, and control it. Once we get it going, it either burns itself out (uses its fuel too quickly), or fizzles out (expends its energy too quickly to start another reaction). This is why pulsed lasers, high compression, and magnetic containment all need to be balanced, and that's the challenge that's been facing fusion for decades.

 

Things like nuclear fission and petroleum these system contain a whole lot of "pent up" energy, much like a highly compressed spring.

Fusion on the other hand is more like the problem of combusting water. You can indeed burn the latter and obtain a self-sustaining reaction. However in order to do so you must FIRST unburn it.

Likewise the precursors for fusion are also in their lowest state. You can get it to fuse, but not for free! It will always require more energy simply due to the law of conservation of energy. You have to force each and every one of those hydrogen atoms together EVERY SINGLE TIME!

Again fission does not have any such requirement. Like petroleum it only requires some kind of "spark" to get things going.

'Pent up' energy is in all mass. (I've already linked to the equations) You seem to think that fusion is somehow a perpetual motion machine. Fusion requires a fuel to work. There is no violation of COM or COE in a fusion reactor because you don't go back to were you started with the same unaltered fuel after energy release in the system from 'burning' that fuel.

The name of the game in all nuclear reactions is this: Decreased mass is accompanied by release of energy. Energy release occurs when the products of either fission or fusion are lower on the curve, downhill in the energy valley. The mass converted to energy in fission is about 0.1%; in fusion it can be as much as 0.7%. These numbers apply whether the process takes place in reactors, bombs, or stars. The high temperatures associated with these nuclear reactions are due chiefly to the kinetic energy of the reaction products, particularly the neutrons.

https://muse.jhu.edu/article/794729/pdf

In March 1963, a general review of Operation Dominic included discussion of the results of the Ripple program, albeit without mentioning it by name: Although the United States did not test any devices of very high yields, tests were conducted of designs which could lead to an entire new class of U.S. weapons. These new weapons could have relatively low weights and extremely high yields, with the fission contribution decreased to only a few percent of the total yield, thus greatly reducing the radioactive fallout from such weapons. The yield to weight ratios of the new class of weapons would be more than twice that which can now be achieved in the design of very high yield weapons using previously developed concepts. . . . New warheads—for example, a 35 Mt warhead for our Titan II—based on these improvements, could be stockpiled with confidence.71

 

IBM creates largest ever superconducting quantum computer

IBM has created the world’s largest superconducting quantum computer, surpassing the size of state-of-the-art machines from Google and from Chinese researchers. Previous devices have demonstrated up to 60 superconducting qubits, or quantum bits, working together to solve problems, but IBM’s new Eagle processor more than doubles that by stringing together 127.

 

IBM creates largest ever superconducting quantum computer

i think Google and Intel adopted the superconducting qubit approach also. Havent read much on it lately though but i think the photonic is the fastest.

But here is something to think about...
Right now most of us have conventional computers. Those run using transistors. The transistors are spaced very very close together to take up a small physical area and also to shorten the transmission paths and capacitance. The control mechanism relies on electron current flow which is slow compared to the speed of light i think because the electrons work in a way similar to the way diffusion works. Also, the time it takes to activate a neighbor relies on the capacitance and that also causes resistive heating which is a major design problem.
But imagine if the signal paths were not only close together but made up out of light pipes or maybe even just a vacuum. This would increase the transmission time and reduce the equivalent capacitance by a large factor. Even with 10nm technology calculate the time it takes for light to travel 10nm. I calculate about 3.33e-17 seconds, which is extremely fast, and we can calculate the equivalent capacitance to figure out how long it would take to activate a neighbor, but it is going to be much much faster than current electron current technology.
I think this would be a good candidate for computations that will be of a structure not fit for quantum computing. Imagine a home computer with this technology.

I am reading that it takes a lot of qubits to make a viable quantum computer i think it takes 9 qubits to make 1 error free qubit, so we may have a long way to go yet but hey it looks like it is happening little by little.

 

When the first transistor was built on one chip, who would have envisioned that they now can put several billion on one chip.
(Maybe Moore's law?)

 

When the first transistor was built on one chip, who would have envisioned that they now can put several billion on one chip.
(Maybe Moore's law?)

I think the first transistor was being thought about circa 1925, then i think invented in 1947. Moore's Law came about circa 1965.

But it is looking more and more (or should i say Moore and Moore ha ha) that Moore's Law is becoming less and less significant as other ideas are coming about which improves processing efficiency.
I always like to mention the game of chess in these types of discussions because making a move is a process that takes time, and if we used Moore's Law alone to predict computer efficiency in the game we would make the mistake of assuming that processing time is the key to all processes and that is not the case except in the raw computing time part of the entire process. In chess the brute-force part of it is certainly almost entirely dependent on the raw computing power, but the emergence of inference cuts the time down considerably as the program learns, and memory helps store those memories so that it becomes a very relevant competitor as time goes on and it learns more and more about the game including the opening, middle game, and endgame. The opening is almost entirely memory so Moore's Law has almost no relevance as the moves are almost instantaneous even with relatively slow computers, and the endgame data base is almost the same. The middle game depends highly on computing power but also in a lot of inference. So Moore's Law makes a big difference in some areas of the process but not in other areas, and inference is also a technology that speeds things up and does so considerably. There are other avenues here too such as parallel processing. I can speed up an arbitrary image rotation by about 4 times by using a core with 4 float point units.
AMD now also has 16 core processors and even 32 and 64 core units. They also use hyper threading so each core can do two threads. That means the 64 core CPU can do 128 threads at a time. Cost though is way up there in the thousands of USD dollars.

Of course there is newer new technology coming out which has nothing to do with the normal semiconductor chip so maybe it is time to abandon Moore's Law, and strictly speaking chip density does not increase doubly every two years anymore anyway.

I like what AMD is doing and actually did with it's new generation of CPU's though, going to a smaller fabrication process. That allowed faster speeds at lower power. Intel however, so far, is sticking with the larger fab process and so to compete with AMD their chips have to dissipate a lot more power. I would say roughly that an Intel chip that competes with a similar AMD chip has to dissipate about double the power. As well as speed to me that means a lot. If an AMD chip runs around 65 watts then a comparable Intel chip will run around 130 watts, roughly. That's a big difference.
And now personally i am faced with maybe sticking with AMD instead of moving back to Intel for my desktop computer. I was really fed up with AMD especially with their FX type CPU's where they called their cores a "single core" just like other manufacturers, but had only one floating point unit for every 2 integer cores. That means that my 8 core processor has 8 full integer cores but only 4 float point cores, a kick in the back. I felt the difference in my image processing routines that slowed down when i went from a 'real' quad core processor to the 8 core 'artificial' processor, and some years later AMD got sued for it (ha ha).

But the long and the short of it is that i cant wait for the day when we can use quantum computing on a regular basis for our home computers.

 

It's back!

https://arstechnica.com/science/202...swamp-error-correction-on-quantum-processors/

So, this is a problem for transmons, and the paper suggests that similar issues could affect other leading technologies. And it's only going to get worse as we build bigger processors in order to boost qubit counts. Can anything be done?

Unfortunately, the paper's authors have to turn to hypotheticals here. They note that astronomers have faced similar problems in designing their imaging hardware and have come up with ways of altering the physical structure of their detector in order to limit the spread of phonons. But it's not clear whether the techniques used there are compatible with quantum processing hardware. But the paper seemingly gives people a very good reason to find out.

https://www.nature.com/articles/s41567-021-01432-8

Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits

 

It's back!

https://arstechnica.com/science/202...swamp-error-correction-on-quantum-processors/


https://www.nature.com/articles/s41567-021-01432-8

Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits

Hello,

I dont know how many people know this but that can also affect home and business computers.
There is a small chance that one or more bits will be flipped in your RAM because of rays from different places both beyond our planet and from the chip package as well.

 

Hello,

I dont know how many people know this but that can also affect home and business computers.
There is a small chance that one or more bits will be flipped in your RAM because of rays from different places both beyond our planet and from the chip package as well.

It's a problem that's been mainly solved on classical computers with ECC because the bit-flipping is usually localized and uncorrelated with isolated sections. With QM an impinging particle can ionize the substrate and induce a burst of quasiparticles that destroys qubit coherence throughout the device, destroying the entire calculation.

https://arxiv.org/pdf/2104.05219.pdf

We have shown direct measurements of widespread, long-lived and highly detrimental correlated events in a practical quantum processor, presenting an existential challenge to quantum error correction. Our results provide a natural explanation for the observations of short periods of significantly elevated error found in recent experiments with stabilizer codes [23, 24]. Our findings are also relevant for other solid-state quantum systems, such as spin qubits that would be sensitive to the induced charges [26], and Majorana fermion devices that would be sensitive to induced quasiparticle population [27, 28]. While the incidence rate can be reduced by shielding [3, 4], the ability of even a single event to cause widespread failure calls for mitigation efforts on the chip itself [14]. We are encouraged by recent works on quasiparticle and phonon trapping in qubits [29–31], and mitigation efforts in astronomical detectors using membranes and phonon down-converters [8]. Adopting these approaches successfully for error correction will rely on an understanding of the detailed evolution of the events, especially as devices increase in size and complexity. We hope that our work spurs research into the physics of correlated events and accelerates the development of mitigation efforts that help enable quantum error correction at scale.

 

It's problem that's been mainly solved on classical computers with ECC because the bit-flipping is usually localized and uncorrelated with isolated sections. With QM an impinging particle can ionize the substrate and induce a burst of quasiparticles that destroys qubit coherence throughout the device destroying the entire calculation.

https://arxiv.org/pdf/2104.05219.pdf

Oh is that why ECC came into existence, or was it just for general error correction?
Not all computers use that kind of memory though so might still get affected, and there may be a maximum number of bits that can flip in order for it to be effective.

But yeah, i think they say they need 8 qubits for every 1 'good' qubit. It's unfortunate that this happens but then those systems are extremely sensitive. Perhaps some magnetic shielding or thick shielding might help.

I always wondered whether the process of human aging wasnt caused in whole or in part because of radiation. The DNA strands get messed up and i believe radiation can easily cause that. A lot all at once is of course bad, but a little over long periods of time (77 years) could account for a lot of apparent aging. This idea of course comes from the DNA damage theory of aging.

 

https://www.technologyreview.com/2022/03/28/1048355/quantum-computing-has-a-hype-problem/

Quantum computing has a hype problem

I am as pro-quantum-computing as one can be: I’ve published more than 100 technical papers on the subject, and many of my PhD students and postdoctoral fellows are now well-known quantum computing practitioners all over the world. But I’m disturbed by some of the quantum computing hype I see these days, particularly when it comes to claims about how it will be commercialized.
...
The qubit systems we have today are a tremendous scientific achievement, but they take us no closer to having a quantum computer that can solve a problem that anybody cares about. It is akin to trying to make today’s best smartphones using vacuum tubes from the early 1900s. You can put 100 tubes together and establish the principle that if you could somehow get 10 billion of them to work together in a coherent, seamless manner, you could achieve all kinds of miracles. What, however, is missing is the breakthrough of integrated circuits and CPUs leading to smartphones—it took 60 years of very difficult engineering to go from the invention of transistors to the smartphone with no new physics involved in the process.

 

These days anything with quantum added to it sells.

 

https://www.technologyreview.com/2022/03/28/1048355/quantum-computing-has-a-hype-problem/

Quantum computing has a hype problem

I read some of the nay sayer stories. Wouldnt it be funny though, if a quantum computer could only solve problems that improve a quantum computer? Ha ha. But of course that's not the case. It has been used on some interesting problems already.
What we also need to look at is the date on the various articles on the web because things are changing very fast these days.