The Quantum Computing Speed Boost Is NOT What You Think 

I love this, all of what you're doing. I watched a TON of Stanford's videos from Leonard S. Its so dense and I just keep throwing myself at it. You are taking concepts I've been trying to get and making them so much more digestible. Please keep explaining the formulas and how they describe what's going on. You're a fantastic teacher. I want longer videos, but also that would come at a cost of production time and real value to each word, so its a wash.

This is the clearest explanation I've seen yet. Please keep up with the video production. Subscribed.

great video ,waiting for the entanglement video😁

Please please make more videos, this is the perfect level of complexity. I’ve watched tons of quantum computing videos and these are the most elucidating by far.

Excellent work 🔥Your explanations of how the whole thing works - with a discussion about quantum gates - are so wonderfully clear! I'm currently scripting a video about quantum computers and their possible industry applications, and I will definitely reference yours as recommended content. Thank you for putting this out there.

Very nice video, with cool visual.

You should make a discord! I think your videos take grand concepts and put them in a manner that's very digestable and if I'm being honest, entertaining as well to learn about. I'd be glad to join and I'm sure many others would be too!

Finally someone explaining me this! Thank you. I've always thought it works something like your waterpath analogy, but all other explanations i found seemed to not confirm that. They've only always talked about the fact that a qbit can be at 0 and 1 at the same time, but with that alone, how would this be so special. Now i got it. can't wait for your explanations of some algorythms! subbed. some questions i hope will be answered in this series: - does the amount of available qbits determine the complexity of a problem a quantum computer can solve? or could any problem be solved already with a few qbits, by some sort of "chaining"? - can we try that out ourselves, either on real systems or simulated ones? - what are specific tasks that a quantum computer can solve currently, detailled examples with your toolbox we've seen in this video. - what are tasks that a quantum computer might be able to solve in the future with better algorythms and/or more qbits? - are there tasks that a quantum computer will never be able to solve, or much slower than a classic one? - currently we seem to work with only o|1 states. could this be extended to more states in the future? would it be useful?

Very well explained. My sincerest congratulations!

instant new subscriber here. love your work - keep it up. you came out of nowhere and made the best Qantum computing youtube videos.

Clear explanation even for someone with a limited physics background

When I watched this video until 2:39 my immediate thought was: Michio Kaku should be put in dilution refrigerator and shielded from the environment for producing (dis?mis?)information theoretic noise about quantum computing xD

Classical computers: Program for a little bit, wait for an eternity for an answer. Quantum computers: Program for an eternity, wait for a little bit for the answer.

I don't understand the title... What you described is exactly what I was expecting. What do most people "think" is the reason for quantum computing power?

it would definitely be worth mentioning QFFT and the Hidden subgroup problem in your next video.

6:42 - We "just" need an algorithm... That's an awfully big "just" - it's *the* problem of quantum computing. In a few nice cases we've found such an algorithm, but we really don't understand how to generate them "generically."

Nice editing and explanation,by the way How many quantum computer giveaway at 100M subs😂

Excellent explanation of how quantum computers are *supposed* to work... but actually don't. Let me explain. The math behind quantum computers goes all the way back to that initial *conjecture* of quantum mechanics that a particle takes all possible paths *simultaneously* ... which, in fact, is *not* how physics works in this universe. The actually correct model of quantum physics is the *pilot wave* one, where a particle is an actual "particle" (a region of space with particle properties, like specific position, specific energy content, etc.), and that "particle" is being guided by a pilot (guiding) "wave" that it produces by its mere existence (via the perturbation of space/changing of potentials in the surrounding spatial "field"/spatial nodes). What actually propagates in all directions ("takes all possible paths through space", though that's not really a correct way of looking at it) is the pilot "wave", whereas the "particle" itself takes *one and only one path* through space, and that path is determined by the interactions of the particle's own pilot wave with pilot waves of all surrounding particles (plus any "reflections" of the particle's own pilot wave caused by the effects of that pilot wave on those other surrounding particles). What all of this means is that, yes, one can never know the *exact* path a particle will take, because the very act of "observation" (measuring the particle via interaction with another particle) will perturb the measured particle, and thus affect its behavior (via its pilot wave), so quantum mechanics is correct in that one regard that one *must* model the behavior of quantum systems as *probabilistic* , since one does not have *enough information* about the system to use a deterministic model (plus, some of the probabilistic behavior of quantum systems have their origin *outside of this universe* , and generally, one can never model events *external to the (measuring) system* as deterministic, since one has no information, whatsoever, about anything external to one's own system [of existence]). So, here's what I really have to say about "quantum computers": *Quantum computers are finite-state machines with probabilistic execution* (meaning, a machine with *deterministic states* and *probabilistic transitions* between those states). To break it all down, what the above statement means is that: a) quantum computer can only take *finite number of states* (which what is usually called "the collapse of the wave function"), b) quantum computer does *not* search the whole problem-space *simultaneously* (since a particle will *always* take *one and only one* path through space), c) particle's pilot *wave* will take all paths through space simultaneously, yes, but that will only give one *the most likely* (with the highest probability) path that a particle *would* (but actually won't) take if it was *completely stationary* (didn't move at all), and thus *didn't interact with anything* ; i.e. if that particle wasn't used to perform any computation at all (by interacting with other particles), and was, therefore, *utterly pointless* to be used in a systems called 'a (quantum) computer' (which is supposed to actually compute something) d) since a particle takes one and only one path *with each execution* of the "quantum computer" algorithm, a "quantum computer" actually searches the problem-space *sequentially* , just like a classical computer does(!), but that searching is done *not deterministically* (or iteratively, one step at a time without repeating any step more than once, as classical computers do), but *probabilistically* , with *no (user) control* over which branch is going to get searched (at any execution step), and the non-zero probability of the same step being searched more than once (which is a lesser problem), and *some branches not being searched at all(!)* (which is a much bigger problem). The latter (bigger) problem means that, not only those 1,000 executions of the IBM's "quantum computer" algorithm may actually not be enough to get a (correct, let alone optimal) solution, but that *solution is not guaranteed for any number of executions that is less than infinite* (number of executions)! To summarize: A "quantum computer" (machine) is to the 21st century what "perpetuum mobile machine" was to the 19th century (before the laws of thermodynamics were formalized), when everybody and their grandmother was trying to get *free energy* out of literally nothing. With "quantum computers", (almost) everybody and their grandmother is now trying to get *free computation* (or, in practice, *free time* not having to be spent on computation) out of literally nothing. More specifically, U.S. "supremacy" in "quantum computing" would be an equivalent of the (early-to-middle) 19th century America claiming to be on the verge of building a free-energy perpetuum-mobile machine, at the moment when all American engineers had already been fully aware of the laws of thermodynamics (and the literal impossibility of such a machine) for some time, but their Chinese and Russian counterparts weren't yet aware of any such laws, so American intelligence services were using that *gap in knowledge* to make Russians and Chinese waste their money, time, and energy (any and all possible efforts, in general) trying to build a literally impossible machine (called "quantum computer").

Greate

It's wrong to try to describe what a superposition "is" precisely. The whole point here is that we're going to make a measurement, and only when we do will we know anything about the state of the system. Feynman counseled us to avoid making specific claims about the history up to that point. We have found mathematics that lets us make good predictions - that's the end of the story right there. That math is not telling us anything about the period for which we have no information.

Is the walsh hadamard transform not just n hadamards applied in parallel?

If Quantum computers give answers to equation in definite numerical values, not values translated from binary ones and zeros like digital computers, then these are by definition analogue computers.

So these quantum computers are like the old time analogue computers?

The on Scott Aaronson’s blog (Scott Aaronson does research on quantum computational complexity, and he very much knows what he’s talking about when it comes to quantum computers), at the top, the header says “If you take nothing else from this blog: quantum computers won't solve hard problems instantly by just trying all solutions in parallel.” So, I would say that your video fell short within the first minute... And your analogy about filling a maze up with water... You say that you’ll explain why it isn’t perfect, but I don’t see what is supposed to be similar at all? ... I guess, the paths that don’t contribute to the solution, stop having flow after a while , and you could *kind of* liken this to computation paths that lead to wrong answers, canceling out? Here’s my gloss: With quantum mechanics, there is stuff that is kind of like normal randomness, where different ways something could happen are assigned different numbers, but unlike in normal probability, instead of these being positive numbers, they are complex numbers, and their absolute values squared sum up to one. And, just like in probability, where if in state S, have probability of p to go to state T in the next step, and in state T have probability q of going to state U in the next step, then this path contributes probability p•q of ending up in state U two steps after being in state S (and there may be other contributions to this) In quantum mechanics, if the amplitude to go from state S to state T in one step is x, and the amplitude to go from state T to state U in the next step is y, then the contribution for going from S to U, coming from this path of “from S to T to U”, is x•y . And, similarly, you have to add up the contributions of all the ways to get from the initial state to the final state, just like with probability. Only, in quantum mechanics, because the amplitudes (unlike probabilities) don’t have to be positive, when adding them up, they can cancel out, or partially cancel out. (But, they have to be exactly the same final outcome for the probabilities to cancel out like that.) Entanglement is when the state of the system as a whole can’t be expressed as just a combination of one state for each of the parts, but is instead a mixture of multiple combinations of a state for each of the parts. Superposition is like a probability mixture, except it has these amplitudes instead of probabilities, and there isn’t necessarily a designated “these would be the configurations that don’t involve uncertainty, which the other things are mixes of”. Instead, e.g. both spin up and spin down can be expressed as a mix (with appropriate amplitudes) of spin left and spin right, but at the same time, spin left and spin right can equally well be expressed as a mix of spin up and spin down. These “mixes” are called “superpositions”, but all that that really means is “multiplying each of the things by some amplitude (I.e. some number) and then adding the things up.”

But the real question is does quantum computer can run minecraft

I just can't buy into it. I don't think there is anything you can say. I'm thinking electric fields are as much quantum as everything else in the world.

They shawdow banned you for some reason

Its all hype. Show me an actual application of Quantum computing.

Fake