To be fair, you were taught this in school if you were taught wave particle duality and the double slit experiment. Look at this. Now imagine a particle bouncing along in very small steps (quantum leaps if you will), and the direction it goes depends on the strength and orientation of the wave where it lands. You may never have been told to think about it like that, but that's what makes physics so amazing that sometimes all it takes is for someone to think about it slightly differently. The information was there all along, but who would imagine the 'particle' bit of an electron interacting with the 'wave' bit - the electron interacts with itself?

I absolutely love it, it's amazing, and simple and beautiful. It may provide insights into new ways we can model quantum behaviour, it might open up new questions to ask.

There's things I'd like to know. First, if the standing waves generated at each step in the droplet's progression interact with each other, the droplet is reacting according to waves it made in the past - what implications does that have for the notion of real particles in a spacetime continuum? For the double slits experiment to work in that model - in the ball on a rubber sheet sense - the sheet would have to stay warped to some extent after the ball had passed. In the quantum sense of the real double slits experiment, we would say it IS a wave, passes through both slits and appears according to statistical probability (the diffraction pattern).

Presumably several droplets released along the same path would go on to take a different route through the slits, to create a diffraction pattern as it must. Perhaps because of fluctuations in the temperature or density of the water at different locations? Is that a limitation of the model or an indicator about the nature of the fabric of spacetime? Perhaps even due to quantum fluctuations in the water particles - the water is never the same twice even if its perfectly still each time - which would potentially mean we're cyclically using quantum mechanics to explain quantum mechanics and we actually haven't explained very much.

The philosophy bit: But this reaches to the heart of the issue with quantum mechanics and perhaps science in general. How accurately can we model reality? The reality is beyond our ability to see, so we can only recreate simpler versions that are always wrong in some way... our idea of what happens - our models - can never be 100% because only a particle in spacetime can perfectly represent a particle in spacetime.

Scientific results and definitions are always defined with limits - "it works like this, within these confines, under these conditions, with these assumptions." There are always error margins. We are always only ever communicating an idea between different consciousnesses, and that idea will never be as true to life as life itself.

Sorry for the wall of text, it's a great and provocative experiment.

I hate quantum mechanics and the absurd implications that extrapolate from it. I always believed that one day we would look back and laugh at how wrong it was. Turns out a more reasonable competing theory has been there all along. Why was I not taught this in school.

I get that it's just another theory and that quantum mechanics can't be judged based on intuition that comes from our interaction with the macro world. Still...fuck quantum mechanics.

There is skepticism that the DWave even actually is a quantum computer:

https://www.wired.com/2014/05/quantum-computing/

I was hoping for more meat to his presentation, and was disappointed. I feel that he said absolutely nothing to help anyone in the audience understand what quantum computers actually DO or what sort of problems they'll help to solve. They'll absolutely not increase your FPS, as that's not what they're well-suited to do. What they are quite excellent at is taking a problem with many possible solutions and finding the correct (or best) one at an extremely high speed.

One example would be the Traveling Salesman problem. In brief, find the optimum route for traversing a number of points on a map. This is useful for things like scheduling package delivery routes, airline flights, etc. With a classic / current computer we write software that cleverly chugs through the possible solutions, throws out any that prove to be poor, and eventually gets to what appears to be the best or is at least a "good enough" solution. As the number of necessary points to be visited increases this problem scales in complexity quickly, so eventually a current computer would just choke on the problem and at best return an ok-ish solution in a reasonable period of time.

A quantum computer is a totally different beast. If it's "big" enough (IE, is comprised of a sufficient number of qubits), it takes the entire set of all possible solutions to the problem, and rather than iterate through them to find the best one, it checks them all simultaneously and immediately returns the optimum solution. It does this by using properties of quantum mechanics, and I think this is where the speaker was drawing his talk of parallel universes. If there are 3 qubits, they would exist as 000, 001, 010, 011, 100, 101, 110, and 111 simultaneously. The software would then define what the best answer would look like, and the computer returns the answer.

You can hopefully see how this totally breaks encryption. With a current computer and a long enough encryption key, an encoded message would take the fastest machines a huge number of years to decipher. With a quantum computer you hand it a gibberish encrypted message, it loads all possible transformations of that message simultaneously, and it then returns the transformation which looks most like a coherent message.

I'm excited to see what these machines can do for us, but they're going to necessitate some significant structural changes in how we handle sensitive data.

One of those "problems conventional computers can't solve" is factoring primes (OK, they can, but it's very slow).

Quantum computers could make this very quick.... Which actually kinda sucks. Because, in a very simplistic sense, all encryption and by extension all electronic transactions depend on factoring primes being hard to do.

Basically quantum computers are going to break the Internet the second they become widely available.

When someone says something like "we're exploiting parallel universes", what they mean is that one of the many theories that can be used to describe quantum behaviour such as entanglement is to do with parallel universes.

That doesn't mean there aren't other theories, it doesn't mean there are parallel universes, it's just one of the few ways we can make it make sense is if it exists and carries information in a dimension that is not tangible to us.

When Archimedes invented his screw, using gravity to drive water uphill, he could have said that he's using an invisible multi-dimensional goblin to move the water; well that's one theory and its irrefutable until Newton makes an appearance. And even then you can still say "yeah but what we know of gravity is still a multidimensional goblin."

Having said that, it has as much likelihood of being correct as any other theory in its infancy.

With the amount of money being spent by really smart people I'm sure something about it is valid. It's just, right now, they're all yammering about facts not in evidence. Also, as their quantum computers are actually slower and less powerful than contemporary computers, occam's razor would suggest it's a elaborate black box scam with a couple Raspberry Pies burbling away inside. Until they start using them to increase my FPS, I'm not buying into the technobabble.

WHAAA?

<siftbot says...

Your video, Are You Ready To Be Outpaced By Machines? Quantum Computing, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.>


Thank you very much...a wonderful surprise.

The more I listen to quantum mechanics the more it sounds like religious nuts. "Oh, we don't know what the qubit is, so that means it's everything, and like 4 or 5 parallel universes too!" it's perpetual motion machines all over again.

Your video, Are You Ready To Be Outpaced By Machines? Quantum Computing, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.

Ye, CD Projekt could ask for my firstborn as payment for Cyberpunk 2077 preorder.

I read an interesting opinion thing about No Man's Sky - that hype can sort of be enjoyed in itself, like when you're a kid the best part of Christmas are the weeks before. Now I actually loathe the run up but I really enjoy the day (which somehow continues to surprise me), but sometimes it is kind of nice to be a kid again and just believe with all the naivete of youth. With the Witcher 3 I actually pretty much had possession of the cake and, simultaneous to having it, I had also eaten it. I really hope they manage to bake another quantum superposition cake because it was/is delicious.

Stuffing the cornucopia into the cornucopia??? That's like dividing by zero. Using quantum phsyics and newtonian physics in the same cake mix. Nuh-uh. Look, hey - all of these nuts could just make phone calls, they could spread insanity, oozing through telephone cables, oozing into the ears of all these poor sane people, infecting them. Wackos everywhere, plague of madness.

Just got around to reading The Quantum Thief, which you recommended about a hundred years ago in one of the 'what are you reading' threads. Thought I'd send a little note of thanks since I really liked it and don't think I would have come across it on my own.

Constructing a sort of crime novel around the subtle implications of technologies that don't exist yet must be difficult work. When a break in the case comes about because the detective realises that, oh of course, since the thief used the key to his encrypted external memory to steal his identity, that must give him access to recordings of the thief's activities during the few minutes of the impersonation, and what's this, he used a quantum entangling drone to beam only one stolen minute of Time away from the victim, there's only one thing that can mean: to the resurrection house! - well it's a step above bootprints in the flower bed isn't it? And calling time-rich nobles 'millenniaires'...mmm, juicy.

A matter of scale, distance & speed. (assuming we are talking about electrically driven engines like ion drives or the proposed EM engine.)

If nothing else, the sun gets weaker the further away you get. Out at the edges of the solar system it's almost negligible.

Given that mass directly effects net thrust & fuel range, smaller craft working in the inner solar system may well be better off sticking with solar over a bulky reactor.

Larger and or longer ranged ships should start to favour fusion reactors and such.

Unless of course they manage to miniaturise the fusion apparatus, or perhaps harness quantum effects like matter/anti-matter. etc. etc.

Surface area to volume ratio also starts to shaft solar power the bigger the ship gets too. The panels would have to get exponentially bigger along with the ship/engines.

I couldn't tell you exactly where, but there will be natural tipping points between the practicality of one over the other.

Edit: The calculation would mostly be the ratio of energy produced to mass of the generating apparatus. The point where a fusion reactor (inc it's fuel) can produce more required power per unit of mass than solar cells (and associated gubbins), is the point where it becomes more efficient for most spacecraft.

Though solar still has a clear advantage where indefinite operational duration is a factor. (fusion requires fuel, albeit in small quantities)