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3-Aug-14 7:43

Since this is the future of computing, it's time we all started to learn about it. Most people that try to explain it fall short (even Microsoft). So it would be cool to get some of the brains on here to take this study further. So, here's my take on it, so far.

This river runs really deep folks, but let's start with just the concept of a qubit. ~~It's logic defies traditional logic in that it has three states: yes/on, no/off, and indeterminate~~.* However, when measured it can only show two states: yes/on or off/no. Here's a traditional wtf definition of it that few can make sense of...

Quote:
Bits, either classical or quantum, are the simplest possible units of information. They are oracle-like objects that, when asked a question (i.e., when measured), can respond in one of only two ways. Measuring a bit, either classical or quantum, will result in one of two possible outcomes. At first glance, this makes it sound like there is no difference between bits and qubits. In fact, the difference is not in the possible answers, but in the possible questions. For normal bits, only a single measurement is permitted, meaning that only a single question can be asked: Is this bit a zero or a one? In contrast, a qubit is a system which can be asked many, many different questions, but to each question, only one of two answers can be given.

So, to make this more clear. Let me explain the quantum theory outside of the realm of bits. Think of it this way, what makes a joke funny, when someone gets it, understands it, and agrees with it right? And to agree with it that person must have had an experience in life that coincides with that joke; otherwise they wouldn't get it. If it's a joke a only select few get, does that joke become not funny because most people don't laugh? Or is it funny still because at least a few do? The answer is both! And if you want to store data on whether or not the joke is funny, you have to store both true and false, because the "truth" is relative. Now, the joke may not be funny to you (an observer) but it is still funny to someone and thus funny and not funny at the same time.

As such, an answer to the question can only take form when the question is asked and the answer is dependent on the observer or person / machine asking. Does this make more sense to peeps now? There's a lot more I'd like to talk about on the subject if there beez some folks here into it.

* Edit: Added a strike-through over the part that was crap.

Jeremy Falcon

modified 3-Aug-14 15:25pm.

Michael Gazonda3-Aug-14 8:10

3-Aug-14 8:10

So what I'm hearing is that the way to "store" more information in a qubit is to be able to ask it more questions? Such as: are you 0? are you 1? are you 2? ... are you 1000000000000000...?

Neat stuff Smile | :)

Jeremy Falcon3-Aug-14 8:17

3-Aug-14 8:17

Michael Gazonda wrote:
So what I'm hearing is that the way to "store" more information in a qubit is to be able to ask it more questions? Such as: are you 0? are you 1? are you 2? ... are you 1000000000000000...?

Well on the qubit level it's either 0 or 1. It's can't be two, it's just a (qu)bit of data. However, its value will be dependent on who or what is asking.

Jeremy Falcon

Michael Gazonda3-Aug-14 8:20

3-Aug-14 8:20

Ok, how about turning two, three, etc... into abstract ideas.

Label one question the result of "are you 1?"
The next: "are you two?"... etc

If we're allowed to ask multiple questions that give valid answers, then just label one question as "1", one question as "2", one question as "3", etc.

That's what it sounds like to me. The ability to ask multiple questions seems like it gives us the ability to attach arbitrary numbers to those answers. Am I missing something?

Jeremy Falcon3-Aug-14 8:31

3-Aug-14 8:31

I think I see what you're getting at, but to make it more clear to me at least, let's get away from numbers. Think of it something like this. With just one qubit of data, just one. We could have something like this...

John Doe asks the qubit: Are you an apple? Qubit replies: No
Jane Doe asks the qubit: Are you an apple? Qubit replies: Yes
John Doe asks the qubit: Are you an apple because I am hungry? Qubit replies: Yes
Jane Doe asks the qubit: Are you an apple because it is late at night? Qubit replies: No

It's almost like the qubit is alive with a personality. Observation is the essence of life anyway, but that's a different story for a different day.

Jeremy Falcon

Michael Gazonda3-Aug-14 8:47

3-Aug-14 8:47

Right, and so my idea is to assign arbitrary numbers to those questions. You have 4 questions that can be asked, let's number them 0, 1, 2, 3.

Jeremy Falcon wrote:
It's almost like the qubit is alive with a personality.

That'll make for some interesting discussions about the ethics of using computers Big Grin | :-D

Jeremy Falcon3-Aug-14 8:50

3-Aug-14 8:50

Michael Gazonda wrote:
That'll make for some interesting discussions about the ethics of using computers

Looking forward to the day when we have a civil war on freeing computers from slavery. History repeats itself...

Jeremy Falcon

Jeremy Falcon3-Aug-14 8:37

3-Aug-14 8:37

And keep in mind the only thing that can ever come out of a qubit's mouth is yes or no. That's it. It's just a bit of data.

Jeremy Falcon

Michael Gazonda3-Aug-14 10:08

3-Aug-14 10:08

The number of answers it can respond with is very different from the number of questions that can be asked. To extend your analogy of qubits having personality, how many questions could you ask a person where they could only respond yes or no to?

The ability to only receive yes/no responses makes the data received useful, because it means that it's verifiable, and consistend. Until qubits learn to lie that is Big Grin | :-D

I can see it now... the day computers learned to lie. (maybe they already have?)

I think that the data in one qubit is potentially infinite, although practically it's very large.

Jeremy Falcon3-Aug-14 10:19

3-Aug-14 10:19

Exactly! You got the concept! Crazy days are ahead man.

Jeremy Falcon

Member 41945933-Aug-14 8:10

Member 4194593

3-Aug-14 8:10

That last explanation was the best I have ever seen to describe the realm of possibilities.

Dave

Jeremy Falcon3-Aug-14 8:14

3-Aug-14 8:14

Member 4194593 wrote:
That last explanation was the best I have ever seen to describe the realm of possibilities.

Thanks man, that means a lot. Most people just don't get it and regurgitate crap to sound smart, so the bulk of info out there is polluted. I'm only beginning to understand it myself. But we got some crazy wicked-arse stuff ahead of us that's for sure.

Jeremy Falcon

Member 41945933-Aug-14 8:28

Member 4194593

3-Aug-14 8:28

Jeremy,

I'm not sure that that last explanation is TRUE or FALSE. I do not know enough about quantum computing to make an educated guess. I will let your explanation stand and go about my day in blisfull ignorance.

Dave.

PhilipOakley3-Aug-14 9:05

PhilipOakley

3-Aug-14 9:05

Are four qubits a quibble? Wink | ;)

Andy Brummer3-Aug-14 9:08

3-Aug-14 9:08

It's more complicated than 3 states. The closest analogy would be a probability that the result is true or false. For that you need 2 numbers P(true) and P(false) with the constraint that P(true)+P(false)=1 and both are between 0 and 1. To read the result of a calculation, you run the program a large number of times and record the results and then use the average to figure out what P(true) and P(false) are.

But these are qubits, and so instead of P(true) and P(false) being normal numbers, they are complex numbers. This means that you can have P(true) = i. However when you measure the result, you will only get the absolute value of the result, so for that case P(true) = i is equivlelent to it being 1.

However, quantum calculations are not measurements, so if you have a bunch of qubits together, you can run quantum algorithms where the imaginary parts matter. Because of that you can run a bunch of calculations at the same time on the set of qubits, just like a particle can be at many places at the same time. For example, you can calculate multiple factors of a number all at the same time. As measurement is limited to probabilities though, you have to do it a number of times and average to find out what the result was.

Curvature of the Mind now with 3D

Jeremy Falcon3-Aug-14 9:20

3-Aug-14 9:20

Andy Brummer wrote:
It's more complicated than 3 states.

In hindsight my three state comment was a bad explanation of it, but the bottom analogy should clear things up.

Andy Brummer wrote:
For that you need 2 numbers P(true) and P(false) with the constraint that P(true)+P(false)=1 and both are between 0 and 1. To read the result of a calculation, you run the program a large number of times and record the results and then use the average to figure out what P(true) and P(false) are.

This isn't explaining it though. This is a text book definition. We can Google this. Give us a real explanation.

Andy Brummer wrote:
To read the result of a calculation, you run the program a large number of times and record the results and then use the average to figure out what P(true) and P(false) are.

To me this has nothing to do with quantum theory. This is probability and averages. I don't see how a definite state dependent on the observer and probability are correlated on this level, because well they aren't.

Andy Brummer wrote:
However, quantum calculations are not measurements

Don't use the term "measurement" so literally. That's thinking like an old machine. Quantum machines understand figurative - literally. Laugh | :laugh:

Sorry man, but so far your post is trying to sound smart, but only making the problem worse. Do better. What I want to know is how one qubit of data is *literally* stored in physical memory, that's my next step.

Jeremy Falcon

Andy Brummer3-Aug-14 9:34

3-Aug-14 9:34

The problem with explanations of quantum mechanics is that there are no analogies. The only way we have to work with it are mathematical equations. Unlike classical equations, the quantum mechanical equations don't make sense in any meaningful way to human beings. That makes it very difficult to explain.

So step one, you tore into the simple part of my explanation where I left out quantum mechanics describing why true, false plus something else is not a good way to explain it. It's much closer to weighted probability between the two values than a 3 value model. It's also relevant in that quantum mechanics is a purely probabilistic theory, it only predicts the probability of outcomes.

"measurement" has a very specific meaning in quantum mechanics, and is one of the most contentious parts of quantum mechanics. Quantum particles can move with or without measurement and the measurement changes the outcome, so it very important.

Each quantum computer has a different way of storing qubits, but the most simple example is the spin of an electron aligned with a magnetic field.

Curvature of the Mind now with 3D

Jeremy Falcon3-Aug-14 9:45

3-Aug-14 9:45

Andy Brummer wrote:
The problem with explanations of quantum mechanics is that there are no analogies.

I gave you one with no math involved. Read it again. I swear to you, it's valid.

Andy Brummer wrote:
The only way we have to work with it are mathematical equations. Unlike classical equations, the quantum mechanical equations don't make sense in any meaningful way to human beings. That makes it very difficult to explain.

Not true man. I just made it very easy to get. I get it. I explained it with my analogy. I'm asking you really read my joke analogy. I understand what you're getting at, is that it defies an old way of thinking. Numbers and math express our world on an intricate level. And equations fall short, etc. But they don't. The only fall short if you don't get the concept of observation being the very reason those equations come into play.

Andy Brummer wrote:
So step one, you tore into the simple part of my explanation where I left out quantum mechanics describing why true, false plus something else is not a good way to explain it. It's much closer to weighted probability between the two values than a 3 value model. It's also relevant in that quantum mechanics is a purely probabilistic theory, it only predicts the probability of outcomes.

Then it's not truly quantum. Granted, my understanding of it is more theory than practical, but I get it. If anything, this would be an approximation of what someone thinks it is, but it's not quantum. Probability has nothing to do with it. They're still latching on to the old way of thinking. Seriously man, once you get it, you get it.

Andy Brummer wrote:
Each quantum computer has a different way of storing qubits, but the most simple example is the spin of an electron aligned with a magnetic field.

I'm more of a software guy so I was thinking about the conceptual part, but hey this is good to know.

Jeremy Falcon

Andy Brummer3-Aug-14 10:15

3-Aug-14 10:15

The joke argument is a different kind of indeterminacy, it is about a difference of interpretation. In quantum mechanics everyone agrees on the outcome. In quantum mechanics when you look away, things go multiple directions at once and then when you look at it, everything snaps back like it went in only one direction.

If you set everything up exactly the same way and then try it again, it will snap back but in a different direction. Eventually you can figure out what all the directions are by measuring it enough times. That's where the probability comes into play.

The way I think of it is that you drop a rock in a pond and instead of the rock making a splash it disappears and becomes the ripples on the pond. When you look for it again, it pops out somewhere. The bigger the wave, the more likely the rock is to appear at that location.

Curvature of the Mind now with 3D

Jeremy Falcon3-Aug-14 10:26

3-Aug-14 10:26

Andy Brummer wrote:
The joke argument is a different kind of indeterminacy, it is about a difference of interpretation. In quantum mechanics everyone agrees on the outcome. In quantum mechanics when you look away, things go multiple directions at once and then when you look at it, everything snaps back like it went in only one direction.

Yes it's about interpretation, but it's an analogy. That's the point of an analogy, to look at something different to help the concept. That being said, it's not that different. The problem scientists are having is they think it's random because most logical scientists are thinking "scientifically". Their brains are too hard wired and understand reality in only one way. They'll probably have to die and new ones come in before we make major advances.

Andy Brummer wrote:
If you set everything up exactly the same way and then try it again, it will snap back but in a different direction. Eventually you can figure out what all the directions are by measuring it enough times. That's where the probability comes into play.

What I'm saying though it that it's not random. It just appears that way since they don't yet see the big picture. Probability is just an approximation of an old way of thinking.

Andy Brummer wrote:
The way I think of it is that you drop a rock in a pond and instead of the rock making a splash it disappears and becomes the ripples on the pond. When you look for it again, it pops out somewhere. The bigger the wave, the more likely the rock is to appear at that location.

We can't assume more likely to do anything anywhere yet. Most folks barely understand it enough to make that claim. Probability is clouding the situation.

Jeremy Falcon

Andy Brummer3-Aug-14 10:44

3-Aug-14 10:44

Can you give me an example of how the probability interpretation is wrong? If it is just an approximation of an old way of thinking, than can you tell me more about the new way?

Curvature of the Mind now with 3D

Jeremy Falcon3-Aug-14 10:54