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Scott’s Supreme Quantum Supremacy FAQ

scottaaronson.com

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Re: Scott’s Supreme Quantum Supremacy FAQ

#131

Post by sanxiyn »

calhoun137 wrote: post #68
dcposch wrote: post #59

Earlier quoted context omitted.

> Once you invest decades of your life into a research subject, if it turns out the entire thing is never going to work, there are major social and financial pressures to deceive the public about the true nature of the subject. You're implying that Scott Aaronson is being deceptive. I think that needs better evidence. The story you linked to is two years old and it's about QC skeptic Gil Kalai. Scott addresses him di…

I am not very familiar with Scott Aaronson and am just making a general observation about the subject of QC, I have no idea what his motivations or intentions are. If Scott believes QC will day be practical and I don't, only time can tell who is right and who is wrong. I have seen this kind of goal post moving in string theory, and its been going on for 20 years with QC in a strikingly similar way imo. There is no wa…

I think Scott is agnostic about whether QC will be practical or not. To quote the original article, "we have no idea how long it will take".

Re: Scott’s Supreme Quantum Supremacy FAQ

#132

Post by reikonomusha »

6gvONxR4sf7o wrote: post #116

>Q12. Even so, there are countless examples of materials and chemical reactions that are hard to classically simulate, as well as special-purpose quantum simulators (like those of Lukin’s group at Harvard). Why don’t these already count as quantum computational supremacy? >Under some people’s definitions of “quantum computational supremacy,” they do! The key difference with Google’s effort is that they have a fully p…

You can do small chemical simulations easily on a processor like this.

Re: Scott’s Supreme Quantum Supremacy FAQ

#133

Post by pgeorgi »

dfsegoat wrote: post #99
ac29 wrote: post #96

Earlier quoted context omitted.

> That doesn't mean we have known path to fusion for power generation. Perhaps this was just a poor example, but we absolutely have a path to fusion power generation. ITER [0][2] is under construction now, and is expected to be capable of 10x power returns. DEMO [1] should have 25x. [0] https://en.wikipedia.org/wiki/ITER [1] https://en.wikipedia.org/wiki/DEMOnstration_Power_Station [2] https://media4.s-nbcnews.com/j/…

From the ITER wiki link: > ITER Project was initiated in 1988. > The expected cost of ITER has risen from US$5 billion to US$20 billion, and the timeline for operation at full power was moved from the original estimate of 2016 to 2027. > A technical concern is that the 14 MeV neutrons produced by the fusion reactions will damage the materials from which the reactor is built ... definitely not clear to me that this is…

> ITER Project was initiated in 1988.

> The expected cost of ITER has risen from US$5 billion to US$20 billion

So factor 4 in 30 years. That's approximately inflation, no?

Re: Scott’s Supreme Quantum Supremacy FAQ

#134

Post by AgentME »

diegoperini wrote: post #29
nexuist wrote: post #2

Preface: I know nothing about quantum computing. What exactly is a qubit? I'm not asking what does it mean, because I know there's superpositions and all that jazz, but as in...like, in an electronic circuit, what is a qubit? Is it made out of logic gates? Which ones? If we can make one qubit, can't we just make a bunch of them by copy and pasting circuits similar to how we used vacuum tubes in the 60s and 70s? How c…

> What exactly is a qubit? A bit is like a boolean type, has the values of true and false. Or you treat those values as 0 or 1, then gather a bunch of bits to build useful numbers. A qubit is like a pair such that these numbers MUST satisfy the following constraints: pair.left^2 + pair.right^2 = 1 pair.left and pair.right can be any complex number Why such a composite type with weird constraints you may ask? Because…

>A bit has the storage capacity of 2 distinct bits of information. A qubit has the storage capacity of 2 complex numbers, which corresponds to 4 floats, which is at least 16*8 bits of information if we are conservative about our assumptions.

This whole explanation makes qubits sound just like a combo-pack of bits, or like something you'd find in an analog computer. They're much more powerful than that because they can be put into superpositions and entangled together while you continue to do calculations with them. Using superpositions and entanglement across qubits can let you solve some problems with lower-complexity algorithms than you could with classical computers.

It's like saying a car is defined by four tires being in close proximity, while skipping the fact that the usefulness of a car comes from the tires being connected together and steered which lets you do things that no amount of unconnected tires could do.

Re: Scott’s Supreme Quantum Supremacy FAQ

#135

Post by sanxiyn »

reikonomusha wrote: post #132
6gvONxR4sf7o wrote: post #116

>Q12. Even so, there are countless examples of materials and chemical reactions that are hard to classically simulate, as well as special-purpose quantum simulators (like those of Lukin’s group at Harvard). Why don’t these already count as quantum computational supremacy? >Under some people’s definitions of “quantum computational supremacy,” they do! The key difference with Google’s effort is that they have a fully p…

You can do small chemical simulations easily on a processor like this.

Really? I haven't seen any molecular simulation proposal that can be run without quantum error correction. I think if there is such a thing it would count as a breakthrough by itself. Any reference?

Re: Scott’s Supreme Quantum Supremacy FAQ

#136

Post by hamilyon2 »

whatshisface wrote: post #4

If it goes well, the history of quantum computing will be divided up in to three eras: the era of twisty philosophical arguments that it's working ("the molecule is simulating itself"), the era of academic arguments that it's working ("we can solve this one carefully constructed problem") and the era of practical arguments ("Amazon is selling QC time for $20/kilogate-bit, what do you mean it's not possible?"). Quantu…

There is market for two, maybe three quantum computers on earth.

Re: Scott’s Supreme Quantum Supremacy FAQ

#137

Post by AgentME »

buboard wrote: post #13
nexuist wrote: post #2

Preface: I know nothing about quantum computing. What exactly is a qubit? I'm not asking what does it mean, because I know there's superpositions and all that jazz, but as in...like, in an electronic circuit, what is a qubit? Is it made out of logic gates? Which ones? If we can make one qubit, can't we just make a bunch of them by copy and pasting circuits similar to how we used vacuum tubes in the 60s and 70s? How c…

for example an electron or a polarized photon. they can take the value 0 and 1 when measured but when not measured they can be in superposition states. Quantum physics forbids copying a qubit to create another, but you can initialize them en masse to to be in a superposition state. Those things are too tiny to be easily manipulated so 53 is quite an accomplishment.

>>If we can make one qubit, can't we just make a bunch of them by copy and pasting circuits similar to how we used vacuum tubes in the 60s and 70s? How come our current limit is only around 54 or so?

>Quantum physics forbids copying a qubit to create another, but you can initialize them en masse to to be in a superposition state. Those things are too tiny to be easily manipulated so 53 is quite an accomplishment.

Quantum physics forbids copying the value of a qubit, but the poster was asking why we couldn't just make more of the device that implements a qubit. The big issue is that you want the qubits to be entangled together and it's hard to prevent decoherence as you make a larger device with more qubits.

Re: Scott’s Supreme Quantum Supremacy FAQ

#138

Post by maccam94 »

ac29 wrote: post #96
sanxiyn wrote: post #88

Earlier quoted context omitted.

I think it is analogous to fusion. Fusion definitely works (the Sun and hydrogen bomb) and power generation is a predicted use of fusion in the future. That doesn't mean we have known path to fusion for power generation. To extend the analogy, quantum supremacy is like fusion for neutron source. There are commercial fusion devices to be used as neutron source.

> That doesn't mean we have known path to fusion for power generation. Perhaps this was just a poor example, but we absolutely have a path to fusion power generation. ITER [0][2] is under construction now, and is expected to be capable of 10x power returns. DEMO [1] should have 25x. [0] https://en.wikipedia.org/wiki/ITER [1] https://en.wikipedia.org/wiki/DEMOnstration_Power_Station [2] https://media4.s-nbcnews.com/j/…

I'm betting Commonwealth Fusion will beat ITER to commercial energy production. Throwing stronger magnets at the problem seems like a promising way to achieve stable fusion.

https://cfs.energy/technology/

Re: Scott’s Supreme Quantum Supremacy FAQ

#139

Post by dredmorbius »

klipt wrote: post #91
ClintEhrlich wrote: post #87

Earlier quoted context omitted.

On second reading, I have but one trivial gripe: "Enormity" implies moral reprobation, so it's a poor way of describing the significance of a computational discovery.

Isn't it just Enormous : enormity :: huge : hugeness?

Both enormous and enormity come from the same etymological roots, enormis "irregular, huge", carrying a connotation of abnormal or irregular, in a negative or bad sense. Enormity specifically came to mean "extreme wickedness" in English, though that meaning is increasingly obscured by usage to mean simply "very big".

Most discerning usage would be that both me "very large scale", but that enormity preserves the meaning of bad at a very large scale.

That's become something of a losing battle as the synonymous usage has become an enormity.

https://www.etymonline.com/word/enormous

https://grammarist.com/usage/enormity-enormousness/

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