(cache) Crucial hurdle overcome in quantum computing

The significant advance, by a team at the University of New South Wales (UNSW) in Sydney appears today in the international journal Nature.

"What we have is a game changer," said team leader Andrew Dzurak, Scientia Professor and Director of the Australian National Fabrication Facility at UNSW.

"We've demonstrated a two-qubit logic gate - the central building block of a quantum computer - and, significantly, done it in silicon. Because we use essentially the same device technology as existing computer chips, we believe it will be much easier to manufacture a full-scale processor chip than for any of the leading designs, which rely on more exotic technologies.

"This makes the building of a quantum computer much more feasible, since it is based on the same manufacturing technology as today's computer industry," he added.

The advance represents the final physical component needed to realise the promise of super-powerful silicon quantum computers, which harness the science of the very small - the strange behaviour of subatomic particles - to solve computing challenges that are beyond the reach of even today's fastest supercomputers.

In classical computers, data are rendered as binary bits, which are always in one of two states: 0 or 1. However, a quantum bit (or 'qubit') can exist in both of these states at once, a condition known as a superposition. A qubit operation exploits this quantum weirdness by allowing many computations to be performed in parallel (a two-qubit system performs the operation on 4 values, a three-qubit system on 8, and so on).

"If quantum computers are to become a reality, the ability to conduct one- and two-qubit calculations are essential," said Dzurak, who jointly led the team in 2012 who demonstrated the first ever silicon qubit, also reported in Nature.

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Until now, it had not been possible to make two quantum bits 'talk' to each other - and thereby create a logic gate - using silicon. But the UNSW team - working with Professor Kohei M. Itoh of Japan's Keio University - has done just that for the first time.

The result means that all of the physical building blocks for a silicon-based quantum computer have now been successfully constructed, allowing engineers to finally begin the task of designing and building a functioning quantum computer.

A key advantage of the UNSW approach is that they have reconfigured the 'transistors' that are used to define the bits in existing silicon chips, and turned them into qubits. "The silicon chip in your smartphone or tablet already has around one billion transistors on it, with each transistor less than 100 billionths of a metre in size," said Dr Menno Veldhorst, a UNSW Research Fellow and the lead author of the Nature paper.

"We've morphed those silicon transistors into quantum bits by ensuring that each has only one electron associated with it. We then store the binary code of 0 or 1 on the 'spin' of the electron, which is associated with the electron's tiny magnetic field," he added.

Dzurak noted that that the team had recently "patented a design for a full-scale quantum computer chip that would allow for millions of our qubits, all doing the types of calculations that we've just experimentally demonstrated."

He said that a key next step for the project is to identify the right industry partners to work with to manufacture the full-scale quantum processor chip.

Such a full-scale quantum processor would have major applications in the finance, security and healthcare sectors, allowing the identification and development of new medicines by greatly accelerating the computer-aided design of pharmaceutical compounds (and minimizing lengthy trial and error testing); the development of new, lighter and stronger materials spanning consumer electronics to aircraft; and faster information searching through large databases.

Explore further: Single-atom writer a landmark for quantum computing

More information: A two-qubit logic gate in silicon, DOI: 10.1038/nature15263

marko

not rated yet Oct 05, 2015

This is an incredible achievement.

A Nobel Prize for Physics must be around the corner.

If the Australian Government had any brains, it would insist the chips and computers be made in Australia and the technological output of this breakthrough be used there first.

There's probably some stupid clause in one of those free trade agreements which might stop this happening.

The timely solutions to intractable problems could be worth more than the sale of the hardware.

Just think about optimising scheduling for global transport operations.

EyeNStein

Lets see them factor 221 with it then?
If a multi qbit array can factor this into two primes (13x17) near instantly on a single chip then the computer world will take notice very rapidly, as all domestic encryption depends on the difficulty of factoring larger primes.

The 8 bit examples of primes multiplied should be an excellent demo of what quantum computers should do readily. The algorithms are waiting for the hardware.

docile

1 / 5 (1) Oct 05, 2015

This is an incredible achievement. A Nobel Prize for Physics must be around the corner.

Why? How? If the computational power of classical computers is already limited with uncertainty principle in many areas, how the switch to quantum computers would overcome it? We can only make computers faster but less precise/deterministic in this way.

qitana

I'm quite surprised myself.
The maximum number of cubits used for computation has been 7.
And now, it could be might be possible to scale it up to 1000's of qubits?
Is that true? No problem with noise destroying the superposition states? No problem with loss of quantum information?

t689

not rated yet 23 hours ago

You can search for "A Two Qubit Logic Gate in Silicon", a paper.
Thatpaper describes a similar scenario of a 2-qubit network, or multiple 2-qubit logic gates linked to form a quantum computer. In that paper, it describes how they believe it is possible using what we have here (pure silicon as your base to put you logic gate on) to amass over 100 of the two-qubit gates to form a usable quantum computer. The video has the scientist stating millions of them, but I haven't looked for a paper that says that.

ProcrastinationAccountNumber3659

not rated yet 22 hours ago

@docile: The transistor in a classical computer is designed under the assumption that you can treat the electron as a particle most of the time. Quantum based computers design the basic computational component by utilizing the particle/wave duality of matter and all the fun that goes along with that.

Quantum based computers and classical computers are used for different applications as mentioned in the article. There is no proposed switch from classic to quantum in this case, these computers are meant for applications where classical computers have difficulty solving problems in any reasonable amount of time.

@qitana I think D-Waves current quantum computer uses 512 qubits. Noise is a huge problems with these machines from what I have read.

not rated yet 21 hours ago

@ProcrastinationAccountNumber3659
From what I am reading and the paper I posted in my previous post and others today, a 2-qubit logic gate is sufficient and I believe the minimum to form a universal quantum computer. And I think that the team at Sydney has performed a significant advance in placing the logic gate on a pure form of silicon at each gate, which from my understanding makes for stable computations. The other article I read developed a scenario with quantum dots on the same form of pure silicon and their research says they could link over 100 of those quantum gates to perform reliable quantum computations. There is no mention of quantum dots in this article, might be wrong, but I see no problem from the other article that they can't link 100 in a completely stable way, which in my opinion would lend credence to the scientist talking about significant advances in healthcare and materials science.

not rated yet 11 hours ago

@ProcrastinationAccountNumber3659

The D-Wave quantum computer isn't considered to be a true quantum computer

not rated yet 9 hours ago

these computers are meant for applications where classical computers have difficulty solving problems in any reasonable amount of time

I'm just saying, that the computational power of classical and quantum computer must converge mutually due to common physical laws. After all, the attempts to make the classical computers faster into account of their indeterminism were already done - in many applications the strict determinism of classical computers isn't necessary. In addition, the classical computers have the same limits of security, like the quantum ones.

Returners

1 / 5 (1) 5 hours ago

I'm hoping this gets used to develop neuromedicine and medicines for metabolic disorders, but let's be real about it. It will probably get used to manipulate the false economy through the stock market, and of course make better weapons for killing people.

We can only hope that muslims are never allowed access to quantum computing technology. There needs to be some sort of universal U.N. ban on muslims using Quantum technology, as well as a constitutional amendment in the U.S. doing the same. We can't have these lunatics developing weapons or computer hacks that could ruin what's left of western civilization.

I'd like to see a computer calculate which race is the best in Starcraft 2, given the same number of actions per minute for each race. Like calculate it for each increment of 50 actions per minute ranging from 50 to 400, and for each of the cross-race matchups to see which race is in face objectively the best.

The reason I say they should be limited to the same actions per minute is because I define game balance as "equal effort provides equal results and equal opportunity to win".

Strangely enough, Blizzard and most of their fan base do not seem to define game balance that way.

3 / 5 (2) 4 hours ago

@Returners: I hope you are not being serious. If you are you have some serious racism problems. You are demonizing a group of 1 billion people for the actions of a relatively small number of extremists.

5 / 5 (1) 3 hours ago

@docile: Classical computation and quantum computation are different. Read this from DWave: http://www.dwaves...g-primer

The first article you linked to doe not demonstrate the point you are trying to make. It just shows the DWAVE-one is not as useful as the company claims.

The second article you linked to is not about using indeterminism. It is pointing out well known thing in engineering should be applied in computing more. Approximate where you can and only be precise when you have to. It basically breaks down to them saying hey guys you know you can approximate 3.1 to 3 for many applications without it mattering.

The method you posted for encryption is interesting. The article does not say they have the same limits. It just shows that classical physics can also be used to create an unbreakable encryption.

not rated yet 2 hours ago

Classical computation and quantum computation are different

Which is why I'm pointing to its common points. The principle/key of understanding is the unification of concepts. If you want understand to things and posts of other readers, you should focus to the facts, which you can agree, not to opposite ones. The common point of classical and quantum computation is the Heisenberg uncertainty principle: the classical computers just operate on the opposite side of information density/processing speed ratio, than these quantum ones, but so far no strategy did prove, that the quantum computers can be more powerful than these classical ones. Quantum computers can be very fast, but they're also of limited resolution and prone to noise. For to achieve the same reliability, which the classical computers provide, we should average their results multiple-times and their speed advantage will vanish.

The quantum computers can be good in applications, where no great precision is required anyway, for example during optical recognition or cataloging of data. For calculation of trajectory with precision, which space-probes require the classical computers are unbeatable. But the classical computers can also utilize parallel algorithms and neural processors, which will wipe out the advantage of quantum computers to a high degree. We should also compare the speed of quantum computers and classical ones running at the same (low) temperature, being overclocked heavily. This all renders the quantum computers as a sorta modern hype, the main substance of which is, it attracts the money into research rather than its actual contributory value. If we would construct classical computer in a way, all details of its technology would run at the limits given with uncertainty principle, its computational power would be comparable with quantum computer, because both computers would run in the same way.

not rated yet 1 hour ago

BTW the quantum computers must be also optimized to particular task for to run effectively (in similar way, like the Von Neumann processor is optimized for sequential calculations). In this regard the so-called analog computers can be perceived also as quantum computers of high degree of redundancy. For example, you can consider the conductive sheet as an entangled system of many q-bits. Gustav Kirchhoff was the first to describe conductive sheets, in an 1845 paper that laid the groundwork for two now-famous laws governing circuits. Kirchhoff realized that a two-dimensional conductive sheet was far more complex than a circuit and potentially could be used to compute the solution of various differential equations and Lagrangian/Hamiltonian physics. The trivial conductive sheet can simulate the distribution of heat with speed, which no digital computer can compete. The existing quantum computers are just miniaturized versions of conductive sheets utilizing so-called quantum annealing.

docile- Can you repeat what you just said

I'll never forget the videos of all those "moderate" muslims dancing in the streets celebrating on 9/11/2001.

Race has nothing to do with it, as the evil religion of islam has spread it's festering cancer to every race in the world.

You can't afford to be so naive.

The extremists get their food, clothing, and shelter from somewhere...

Oh yeah, *cough, cough* they get it from the "moderates" donations to their organizations.

Antisorc

not rated yet 4 minutes ago

You are one, very deluded individual. You can't afford to be so ignorant in this day and age. Firstly, why even bring up religion here? Secondly, don't forget that it was the very Muslims you are vilifying who ensured this research could take place...hundreds of years ago when they saved Greek works from destruction and added their own scientific breakthroughs in math, optics, physics etc.

Open your eyes man and stop watching Fox News