What is a quantum computer?

How does science work? And what's all this about quantum mechanics?

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Philosophy Explorer
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What is a quantum computer?

Post by Philosophy Explorer » Thu Dec 10, 2015 12:57 am

Over the past few weeks, it's been reported that D-Wave has created a quantum computer and yesterday Google says further testing shows the D-Wave 2 computer is over 100 million times faster than any other computer in the world.

This has led to disagreement and confusion among members here. What is a fair test that compares a quantum computer with another? Is this a hoax? (I seriously doubt it as NASA and Google have poured money and their reputations into this project). How do we know we have the real McCoy?

I googled what is a quantum computer and got back Wikipedia at the top of the list so I'm using that to get this thread started. If you disagree with the article or any other part of the thread, state your reasons why. If someone says something which isn't clear, I'll jump in for clarification as I'm here to learn same as you or you or YOU. I won't jump in to disagree as this thread is for you.

I hope the thought police don't take down this thread because it has a link. Let it run for a week for response.

Here's the article:

https://en.m.wikipedia.org/wiki/Quantum_computing

PhilX

999yards
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Re: What is a quantum computer?

Post by 999yards » Tue Dec 15, 2015 12:09 am

There are much better explanations on YouTube Google tech talks.

The best I can do is tell you they use quidbits of information instead of binary code 01. However, it's not simply 4 bits as each entangled pair have an infinite number of spin positions.

They still have a very long way to go to equal the calculating capacity of the brain though.

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sat Dec 26, 2015 8:17 am

An issue has arisen as to how practical D-Wave's computer (Google and NASA) is? I don't regard that as too relevant because as the saying goes, science marches on.

Nothing says that the D-Wave computer won't find uses as time moves along. It's like baking soda that found another use as time moved along. Currently D-Wave has achieved a proof of concept so in a theoretical sense, a quantum computer has been created. When will a "practical" quantum computer come along? - I'm seeing estimates ranging from 10 years to decades.

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Re: What is a quantum computer?

Post by Obvious Leo » Sat Dec 26, 2015 10:52 am

A quantum computer is a computer which processes information at the speed of light. The universe is the best known example of one.

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sat Dec 26, 2015 11:00 am

Obvious Leo wrote:A quantum computer is a computer which processes information at the speed of light. The universe is the best known example of one.
Are you sure about that Leo? Compare with Wikipedia above.

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Re: What is a quantum computer?

Post by Obvious Leo » Sat Dec 26, 2015 11:54 am

Philosophy Explorer wrote:Are you sure about that Leo?
I'm absolutely positive. Forget Wiki and read David Deutsch.

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sat Dec 26, 2015 12:03 pm

Obvious Leo wrote:
Philosophy Explorer wrote:Are you sure about that Leo?
I'm absolutely positive. Forget Wiki and read David Deutsch.
Aside from Wiki, it's been consistently stated that a quantum computer can take on many values between 0 and 1 qubits which I take as part of its operating definition. Why do you suggest David Deutsch?

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Re: What is a quantum computer?

Post by Obvious Leo » Sat Dec 26, 2015 12:13 pm

Philosophy Explorer wrote: Why do you suggest David Deutsch?
He's widely regarded as the leading theorist in the field and in my view he has the best grasp of the specific principles involved. Having said that, I agree with Deutsch that nobody really knows what a quantum computer is and this includes himself and the other people who are in the process of inventing them. Deutsch does not regard the infinite superpositions as physically real phenomena but merely as a convenient way of mathematically representing some underpinning phenomenon which still remains unknown.

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sun Dec 27, 2015 10:37 pm

Obvious Leo wrote:A quantum computer is a computer which processes information at the speed of light. The universe is the best known example of one.
According to this article, we're not quite there yet Leo. TBH, this is the first time I've ever seen anyone say that the universe is a computer that can process information at the speed of light - what type of information are you talking about here? Are you sure you haven't misinterpreted? Here's the article that just came out (note though this article says nothing in relationship to quantum computing, but a very fast computer would be a very fast computer, regardless of how it does it):

http://motherboard.vice.com/read/design ... -few-years

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Re: What is a quantum computer?

Post by Obvious Leo » Sun Dec 27, 2015 11:31 pm

Philosophy Explorer wrote: TBH, this is the first time I've ever seen anyone say that the universe is a computer that can process information at the speed of light.
It shows you haven't been following my posts because this is the way I've defined the universe in many of my posts on physics topics.
Philosophy Explorer wrote: Are you sure you haven't misinterpreted?
It depends which way you look at it. This is not the way to interpret the theory because spacetime physics is not an information theory. However it's the way to interpret the EVIDENCE, which of course is a wholly different matter. The universe is a PROCESS and processes occur at a finite speed. That's what the speed of light IS, the processing speed of the universe.

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sun Dec 27, 2015 11:37 pm

Obvious Leo wrote:
Philosophy Explorer wrote: TBH, this is the first time I've ever seen anyone say that the universe is a computer that can process information at the speed of light.
It shows you haven't been following my posts because this is the way I've defined the universe in many of my posts on physics topics.
Philosophy Explorer wrote: Are you sure you haven't misinterpreted?
It depends which way you look at it. This is not the way to interpret the theory because spacetime physics is not an information theory. However it's the way to interpret the EVIDENCE, which of course is a wholly different matter. The universe is a PROCESS and processes occur at a finite speed. That's what the speed of light IS, the processing speed of the universe.
Then this is your interpretation. Still it's a very long stretch to say that the universe is a computer.

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Re: What is a quantum computer?

Post by Obvious Leo » Sun Dec 27, 2015 11:41 pm

Philosophy Explorer wrote:Still it's a very long stretch to say that the universe is a computer.
Have you got a better definition for an entity which creates reality?

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Re: What is a quantum computer?

Post by Philosophy Explorer » Sun Dec 27, 2015 11:54 pm

Obvious Leo wrote:
Philosophy Explorer wrote:Still it's a very long stretch to say that the universe is a computer.
Have you got a better definition for an entity which creates reality?
LOL. Not long ago, you were saying the universe wasn't real. Looks like you changed your mind about that.

So what type of information is the universe supposed to be processing? Is it in the form of qubits?

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Re: What is a quantum computer?

Post by Obvious Leo » Mon Dec 28, 2015 12:47 am

Philosophy Explorer wrote:. Not long ago, you were saying the universe wasn't real.
I never once said that and I defy you to indicate where I did. What I have said repeatedly is that what the observer observes is not the real universe and the reason why I have repeatedly pointed this out is because the speed of light is finite and therefore the observer can only observe a holographic representation of his own past and the past is that which no longer exists. This is not a very difficult metaphysical concept to grasp, Phil, and your attempt to misrepresent what I'm saying does you no credit.
Philosophy Explorer wrote: So what type of information is the universe supposed to be processing? Is it in the form of qubits?
If the universe is modelled as a computation then energy and information are entirely synonymous constructs. We already know that matter and energy are equivalent so at the Planck scale the informational bits can be thought of as quanta of energy. I've several times suggested that you take a look at John Conway's Game of Life for a visual representation to see how quanta of energy can encode for informational complexity according to no law at all other than the meta-law of cause and effect. This is the sole organising principle needed for the Universal Turing Machine which is our self-causal universe.

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Arising_uk
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Re: What is a quantum computer?

Post by Arising_uk » Mon Dec 28, 2015 12:58 am

Philosophy Explorer wrote:
Then this is your interpretation. Still it's a very long stretch to say that the universe is a computer.

PhilX
Depends what kind of computer you are talking about? But the idea has been around a long time, Zuse was one of the first I think and latterly Fredkin has had a nice take upon such matters.

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