Quantum Phenomenon shown in Quantum Computer

[Torand]

  

Hmm, Tikka Sauce: http://www.bbc.co.uk/news/science-environment-27632140

 

 

 

 

 

Quantum phenomenon shown in $15m D-Wave computer

D-Wave released its first commercial quantum computer in 2011, and is set to release a more powerful chip later this year

Scientists says they have obtained the best evidence yet for an important quantum physics phenomenon inside a $15m computer built by a Canadian firm.

D-Wave claims it has built the first practical quantum computer, a type of machine that could solve complex problems faster than is possible today.

Scientists say they have shown that an effect called "entanglement" is present in eight units of quantum information.

Entanglement is a key step towards building a practical platform.

The results have just been published in the peer-reviewed journal Physical Review X.

D-Wave, based in Burnaby, outside Vancouver, has courted controversy with its claim to have built a practical quantum computer, a feat that was thought to be decades away.

In a tangle

Quantum computing exploits the strange physics of quantum mechanics, which takes hold at tiny (atomic or sub-atomic) scales.

The basic units of information in classical computers are called "bits" and are stored as a string of 1s and 0s, but their equivalents in a quantum system - qubits - can be both 1s and 0s at the same time.

Continue reading the main story

What is quantum physics?

There are things we take for granted about the world around us. Let go of your smartphone and it will fall to the ground. Pull the handle on a drawer and it will open. These familiar rules can be described by the principles of classical mechanics.

But in the late 19th and early 20th Centuries, scientists were beginning to realise that classical physics could not explain certain phenomena seen at very large and very small scales.

This spawned two revolutions: one was relativity and the other quantum mechanics. Early experiments suggested light was a wave, rather than a stream of particles. In quantum theory, light can be both a particle (the photon) and a wave.

One principle central to quantum mechanics is that a particle, such as an electron, can exist in all of its possible states simultaneously - known as superposition. Another important idea is that of entanglement, a phenomenon whereby objects become linked, even if they lie far apart.

But the qubits need to be synchronised using a quantum effect known as entanglement, which Albert Einstein dubbed "spooky action at a distance".

"This is the first peer-reviewed scientific paper that proves entanglement in D-Wave processors," Dr Colin Williams, director of business development at D-Wave, told BBC News.

"What's even more remarkable is that this is the largest demonstration of entanglement in any quantum, superconducting computing scheme so far," he said. "It's a big achievement for the field."

They also showed that the entanglement was stable, persisting throughout a critical operation of the processor.

The vast majority of academic research into this area of computing is based around the model of "quantum gates". These are the quantum equivalents of the logic gates that form the building blocks of circuits in classical computing.

But D-Wave has taken a different approach known as quantum annealing. On a particular type of mathematical challenge known as an optimisation problem, annealing can, in theory, short-cut classical computers to the best answer.

 

Working together

The authors of the latest study used one of the qubits as a "probe" to provide information on the other qubits in D-Wave's processor. Using this information, they were able to calculate how much entanglement there was in the system.

Dr Federico Spedalieri of University of Southern California's Viterbi Information Sciences Institute and co-author of the paper, said: "There's no way around it. Only quantum systems can be entangled. This test provides the experimental proof that we've been looking for."

Prof Alan Woodward, from the University of Surrey, told BBC News: "One of the three quantum effects that you need for it to be defined as a true quantum computer is entanglement."

Calling the result "a big deal", he added: "It does appear to be conclusive that they have a large number of qubits entangled and they do see to be working together."

 

D-Wave's processor uses 512 qubits, but the technique in the latest study was able to characterise only eight qubits.

 

Sceptics about D-Wave computers such as Prof Scott Aaronson of the Massachusetts Institute of Technology (MIT) say the machines show "pretty good" evidence for entanglement at a local level, but not necessarily on a large scale.

But in response, Dr Williams said there was reason to believe entanglement is pervasive across the processor.

"We could have chosen any part of the processor to do this experiment on," he explains, adding: "There's no reason to believe the entanglement is limited to just these eight qubits.

"We've done other experiments to determine entanglement in different unit cells and we see similar results."

Prof Woodward commented: "In quantum physics, one of the really difficult things is to witness something because as soon as you witness something, you interfere with it.

"By being a witness, you have to be careful you don't become part of what you're seeing. But the techniques they've used are generally accepted as showing what they are able to show: entanglement among a fairly large number of stable qubits."

However, sceptics doubt that the machines are leveraging quantum physics for any performance boost relative to classical machines.

While entanglement is required to get quantum "speed-up", they argue that it is perfectly possible to have entanglement without speed-up.

In one study released in 2013, Catherine McGeoch of Amherst College in Massachusetts, a consultant for D-Wave, found the machine was 3,600 times faster on some tests than a desktop computer.

But a study published earlier this earlier year by Matthias Troyer from ETH Zurich in Switzerland and colleagues pitted the D-Wave machine against a standard high-spec desktop computer.

On some tests chosen by the team, D-Wave's machine was found to offer no performance boost over the regular computer.

However, D-Wave maintains that the tests used by Prof Troyer's team were not ones where the company's computer offers any advantage. Indeed, Dr Williams even argues that the random challenges were too easy for the computer, which was designed to tackle a very difficult and specialised class of problems.

Dr Williams said the stability of entanglement revealed in the latest study further underlined that quantum annealing was more robust than the gate model of quantum computing.

Lab devices based on the gate model suffer from dropout, where the qubits lose their ambiguity and become straightforward 1s and 0s. This has in part ensured that quantum computers remain confined to the lab.

Quantum annealing is not as susceptible to this dropout problem, but advocates of the gate model argue that D-Wave's approach can't provide the performance boost theoretically possible with gates.

 

 

 

 

 

 

 

 

 

OK, so, it's not 100% proven that quantum computing is yet 'a thing', which is what this article is about, trying to/taking steps toward proving that this technology is acting as it is designed to and showing signs of quantum computing theories working, the main one discussed in this article is mainly the entanglement. This is seriously exciting and at the same time *mind-blown*.

 

 

...their equivalents in a quantum system - qubits - can be both 1s and 0s at the same time.

 

It's the qubits that get me, being both a 1 and a 0 at the same time. Also, imagine folding on this thing...

 

 

 

 

The vast majority of academic research into this area of computing is based around the model of "quantum gates". These are the quantum equivalents of the logic gates that form the building blocks of circuits in classical computing.

But D-Wave has taken a different approach known as quantum annealing. On a particular type of mathematical challenge known as an optimisation problem, annealing can, in theory, short-cut classical computers to the best answer.

 

Going along with the binary, the Logic. I'm really intrigued about how Logic is going to translate over from binary systems (as said in the aticle, 'quantum annealing') with the qubits having a floating state, sync'd with entanglement. I'm certainly going to have to read into 'quantum annealing' and how it, in theory, changes some tasks that require logic.

 

Imagine smart if statements, where instead of the program returning false, it sifts through the program so far and tries to make logical connections to a correct solution. Like the human brain would. You would, obviously, still need just a regular if statement for most things, but it would be cool to see none-the-less.

 

 

 

D-Wave's processor uses 512 qubits, but the technique in the latest study was able to characterise only eight qubits.

 

So unfortunately, it's not 100% utilised yet, but getting there! One step at a time.

 

 

 

 

Sceptics about D-Wave computers such as Prof Scott Aaronson of the Massachusetts Institute of Technology (MIT) say the machines show "pretty good" evidence for entanglement at a local level, but not necessarily on a large scale.

But in response, Dr Williams said there was reason to believe entanglement is pervasive across the processor.
 

"We could have chosen any part of the processor to do this experiment on," he explains, adding: "There's no reason to believe the entanglement is limited to just these eight qubits.

"We've done other experiments to determine entanglement in different unit cells and we see similar results."

 

So, as said before, still early days, but promising none-the-less.

 

Let's see what the future brings! 

 

[Guest]

I saw a TedTalk recently that stated if we had a 300 qubit machine then it would potentially be enough to calculate the entire universe due to the Travelling Salesman problem.

 

That's a single 300 qubit processor...

 

“The entangled states represent extra ‘codes’ in a quantum computer,  which classical computers do not possess. Their number grows exponentially with the number of qubits. As a consequence, with just 300 qubits it is possible to store as much information as there are atoms in the universe,” says Morello. - http://newsroom.unsw.edu.au/news/quantum-computing-taps-nucleus-single-atom

 

This was the fascinating video in question: 

[Torand]

Crazy long post....

But as a physics major, very exciting!

 

Things like this tend to interest me, so I end up getting more out of it. Haha.

 

 

I saw a TedTalk recently that stated if we had a 300 qubit machine then it would potentially be enough to calculate the entire universe due to the Travelling Salesman problem.

 

That's a single 300 qubit processor...

 

“The entangled states represent extra ‘codes’ in a quantum computer,  which classical computers do not possess. Their number grows exponentially with the number of qubits. As a consequence, with just 300 qubits it is possible to store as much information as there are atoms in the universe,” says Morello. - http://newsroom.unsw.edu.au/news/quantum-computing-taps-nucleus-single-atom

 

This was the fascinating video in question: "https://www.youtube.com/watch?v=cugu4iW4W54"

 

Interesting!

 

So in theory, with current technology, if they figure out how to use all 512 qubit processors and the machine works 100% as intended following quantum computing, we could calculate the universe.

 

Neat!

 

(quote marks around the video are on purpose) 

[Guest]

I was so utterly awe-struck when she shows pictures of individual atoms and then explains in fairly simple terms how they move and construct these atomic scale transistors.  Truly incredible.

[ACatWithThumbs]

Things like this tend to interest me, so I end up getting more out of it. Haha.

 

 

 

Interesting!

 

So in theory, with current technology, if they figure out how to use all 512 qubit processors and the machine works 100% as intended following quantum computing, we could calculate the universe.

 

Neat!

 

(quote marks around the video are on purpose) 

Imagine CGI or a game running on a quantum computer

 

[Guest]

Imagine the CGI or game running on a quantum computer

 

You might already be looking at some....

 

Evidence continues to mount around the theory that our universe and everything in it is a holographic projection

[Mister Snow]

Very interesting. Hope we see some big improvements by the end of this decade. The big problem of dealing with quantum particles is how to effectively measure the state of observed particle without affecting that state and changing it so I am interested to see new methods of doing this.

[b45op]

There were some words I understood in there and many I didn't but still its cool as hell!

[Commander Llama]

I saw a TedTalk recently that stated if we had a 300 qubit machine then it would potentially be enough to calculate the entire universe due to the Travelling Salesman problem.

 

That's a single 300 qubit processor...

 

Not sure what is meant by calculate the universe...  I suppose she meant represent the universe?  Possible...

 

A qubit can have a value of 0, or 1, or a superposition of other qubit states.  The number of possible superpositions is exponential.  There are 2^N possible superpositions for N qubits.  So for a 300 qubit processor, that's 2^300 possible superpositions.  We estimate the universe has about 10^80 atoms, so yeah it works out.

 

Of course there's a lot of hype for this technology despite it being in its infancy.  I suppose it's naive to say where we will "go" with this technology, but from where we stand now, quantum computing isn't a solve-anything technology.  It's incredibly complex and some theoretical studies show it can tackle some classical problems with hilarious ease.  Of course, it needn't replace classical systems either, for things that classical systems do fine (like let me write this post, or stream YouTube )

[sof006]

I want one Gimme!

[tharvey]

This really is exciting technology.  I can't wait to see what the future will be like in 10 years or 20 years.