Commercial Quantum Computer?

Quantum computers could revolutionize the way we tackle problems that stump even the best classical computers.
Single atom transistor recently introduced has been seen as a tool that could lead the way to building a quantum computer. For general introduction how quantum computer work, read A tale of two qubits: how quantum computers work article.

D-Wave Announces Commercially Available Quantum Computer article tells that computing company D-Wave has announced that they’re selling a quantum computing system commercially, which they’re calling the D-Wave One. D-Wave system comes equipped with a 128-qubit processor that’s designed to perform discrete optimization operations. The processor uses quantum annealing to perform these operations.

D-Wave is advertisting a number of different applications for its quantum computing system, primarily in the field of artificial intelligence. According to the company, its system can handle virtually any AI application that can be translated to a Markov random field.


Learning to program the D-Wave One blog article tells that the processor in the D-Wave One – codenamed Rainier – is designed to perform a single mathematical operation called discrete optimization. It is a special purpose processor. When writing applications the D-Wave One is used only for the steps in your task that involve solving optimization problems. All the other parts of your code still run on your conventional systems of choice. Rainier solves optimization problems using quantum annealing (QA), which is a class of problem solving approaches that use quantum effects to help get better solutions, faster. Learning to program the D-Wave One is the first in a series of blog posts describing the algorithms we have run on D-Wave quantum computers, and how to use these to build interesting applications.

But is this the start of the quantum computers era? Maybe not. D-Wave Announces Commercially Available Quantum Computer article comments tell a story that this computer might not be the quantum computer you might be waiting for. It seem that the name “quantum computer” is a bit misleading for this product. There are serious controversies around the working and “quantumness” of the machine. D-Wave has been heavily criticized by some scientists in the quantum computing field. First sale for quantum computing article tells that uncertainty persists around how the impressive black monolith known as D-Wave One actually works. Computer scientists have long questioned whether D-Wave’s systems truly exploit quantum physics on their products.

Slashdot article D-Wave Announces Commercially Available Quantum Computer comments tell that this has the same central problem as before. D-Wave’s computers haven’t demonstrated that their commercial bits are entangled. There’s no way to really distinguish what they are doing from essentially classical simulated annealing. Recommended reading that is skeptical of D-Wave’s claims is much of what Scott Aaronson has wrote about them. See for example, although interestingly after he visited D-Wave’s labs in person his views changed slightly and became slightly more sympathetic to them

So it is hard to say if the “128 qubits” part is snake oil or for real. If the 128 “qubits” aren’t entangled at all, which means it is useless for any of the quantum algorithms that one generally thinks of. It seem that this device simply has 128 separate “qubits” that are queried individually, and is, essentially an augmented classical computer that gains a few minor advantages in some very specific algorithms (i.e. the quantum annealing algorithm) due to this qubit querying, but is otherwise indistinguishable from a really expensive classical computer for any other purpose. This has the same central problem as before: D-Wave’s computers haven’t demonstrated that their commercial bits are entangled.

Rather than constantly adding more qubits and issuing more hard-to-evaluate announcements, while leaving the scientific characterization of its devices in a state of limbo, why doesn’t D-Wave just focus all its efforts on demonstrating entanglement, or otherwise getting stronger evidence for a quantum role in the apparent speedup? There’s a reason why academic quantum computing groups focus on pushing down decoherence and demonstrating entanglement in 2, 3, or 4 qubits: because that way, at least you know that the qubits are qubits! Suppose D-Wave were marketing a classical, special-purpose, $10-million computer designed to perform simulated annealing, for 90-bit Ising spin glass problems with a certain fixed topology, somewhat better than an off-the-shelf computing cluster. Would there be even 5% of the public interest that there is now?


  1. Tomi Engdahl says:

    How D-Wave began selling its quantum computer amid suspicion that it relied on classical computing:

    The Age of Quantum Computing Has (Almost) Arrived

    Inside the Black Box

    The guts of a D-Wave don’t look like any other computer. Instead of metals etched into silicon, the central processor is made of loops of the metal niobium, surrounded by components designed to protect it from heat, vibration, and electromagnetic noise. Isolate those niobium loops well enough from the outside world and you get a quantum computer, thousands of times faster than the machine on your desk—or so the company claims. —Cameron Bird

    Is the D-wave actually quantum? if noise is disentangling the qubits, it’s just an expensive classical computer.

  2. Tomi Engdahl says:

    First Browser-Based Quantum Computer Simulator Released

    “Google researchers unveiled the first browser-based, GPU-powered Quantum Computing Playground. With a typical GPU card you can simulate up to 22 qubits, write, debug, and share your programs”

  3. Tomi Engdahl says:

    Quantum Computing Playground

    Quantum Computing Playground is a browser-based WebGL Chrome Experiment. It features a GPU-accelerated quantum computer with a simple IDE interface, and its own scripting language with debugging and 3D quantum state visualization features. Quantum Playground can efficiently simulate quantum registers up to 22 qubits, run Grover’s and Shor’s algorithms, and has a variety of quantum gates built into the scripting language itself.

    Technology: WebGL, JavaScript, HTML5, AngularJS, Bootstrap

  4. Tomi Engdahl says:

    Get UNCRACKABLE quantum keys – from a smartphone
    Would take ’1018 times the age of the universe’ to guess

    Your smartphone is a quantum device that can be used to generate truly random keys, according to boffins at the University of Geneva.

    The authors say that smartphone CMOS cameras are now sensitive enough to take the place of expensive kit. “Their readout noise is of the order of a few electrons and their quantum efficiencies can achieve 80 per cent”, the paper states.

    That’s a lot cheaper than the QRNG kit currently on offer – although it’s more expensive than visiting the ANU’s online QRNG site.

  5. Tomi Engdahl says:

    Quantum teleportation gets reliable at Delft
    ‘Einstein wrong!’ is always so popular

    A research group at Delft University of Technology has set the lesser-brained among the world’s science writers in an absolute tizz by demonstrating what it describes as reliable quantum teleportation.

    Of course, mention quantum phenomena like entanglement (and therefore teleportation) and the only angle anyone can think of is “Einstein was wrong”, as if the whole idea were new.

    Unless they’re completely off beam and think this is the first quantum teleportation ever.

    Its paper, published at Science (abstract) and available in pre-print version at Arxiv, claims not to be the first information teleportation, but rather the first reliable teleportation.

    Getting quantum-scale particles – electrons, photons, or even atoms – entangled is difficult, separating them is difficult, measuring their state is difficult, and most of all, preserving entanglement in the presence of noise is difficult.

    That makes error rates a problem: noise destroys entanglement, and if you’re communicating information via quantum states, that might mean dozens of states have to be prepared and measured.

    Reliable “single-shot” entanglement measurements would therefore make quantum communications systems operate at much higher bitrates than today.

    The Delft group, led by professor Ronald Hanson, are laying claim to reliable information teleportation between qubit pairs separated by three metres.

    As Hanson says in the release, “The unique thing about our method is that the teleportation is guaranteed to work 100 per cent. The information will always reach its destination, so to speak. And, moreover, the method also has the potential of being 100 per cent accurate.”

  6. Tomi Engdahl says:

    Quantum Cryptography

    Classical cryptography provides security based on unproven mathematical assumptions and depends on the technology available to an eavesdropper. But, these things might not be enough in the near future to guarantee cyber security. We need something that provides unconditional security. We need quantum cryptography.

    What is quantum cryptography? Quantum cryptography is a complex topic, because it brings into play something most people find hard to understand—quantum mechanics. So first, let’s focus on some basic quantum physics that you’ll need to know to understand this article.

  7. Tomi Engdahl says:

    Boffins discover ‘practical requirements’ for ‘realistic’ QUANTUM COMPUTER
    One of key ingredients is ‘contextual’ magic states

    Canadian boffins have brought quantum computers a step closer to reality by identifying one feature that will be key to finally building one – contextuality.

    Our computers use the binary system of 1 and 0s. Quantum computers use qubits (quantum bits), which can exist in “superposition”, meaning that they can be a 0 or a 1 and everything in between… simultaneously.

    Quantum researchers have known for 50 years that context is king when it comes to quantum theory.

    To make the system work properly, quantum computing boffins need a way of controlling “the fragile quantum states”. One such way of doing so is building a particular type of noise-resistant environment, and “magic-state distillation” is one approach to doing this.

    The new study has found that contextuality could be key to the “magical state” model of fault-tolerant quantum computation.

  8. Tomi Engdahl says:

    D-Wave disputes benchmark study showing sluggish quantum computer
    Faulty benchmarks and sampling methods all wrong, claim Canadian quantumoids

    Quantum computing device manufacturer D-Wave is disputing a recently published study that claims the Canadian firm’s systems aren’t reliably faster than more-conventional computing systems.

  9. says:

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  10. Tomi Engdahl says:

    Microsoft Makes Bet Quantum Computing Is Next Breakthrough

    Modern computers are not unlike the looms of the industrial revolution: They follow programmed instructions to weave intricate patterns.

    Now a group of physicists and computer scientists who are funded by Microsoft are trying to take the analogy of interwoven threads to what some believe will be the next great leap in computing, so-called quantum computing.

    If they are right, their research could lead to the design of computers that are far more powerful than today’s supercomputers and could solve problems in fields as diverse as chemistry, material science, artificial intelligence and code-breaking.

    The proposed Microsoft computer is mind-bending even by the standards of the mostly hypothetical world of quantum computing.

    In the approach that Microsoft is pursuing, which is described as “topological quantum computing,” precisely controlling the motions of pairs of subatomic particles as they wind around one another would manipulate entangled quantum bits. Although the process of braiding particles takes place at subatomic scales, it is evocative of the motions of a weaver overlapping threads to create a pattern.

    By weaving the particles around one another, topological quantum computers would generate imaginary threads whose knots and twists would create a powerful computing system. Most important, the mathematics of their motions would correct errors that have so far proved to be the most daunting challenge facing quantum computer designers.

  11. Tomi Engdahl says:

    D-Wave Systems Raises $28.4 Million Round

    Quantum computing technology company D-Wave Systems has raised a new $28.4 million round of funding, according to a new filing on the SEC’s site.

  12. Tomi Engdahl says:

    Another step forward for diamond-based quantum computers
    Square cut or pear-shaped, these qubits don’t lose their shape

    Building simple quantum gates is common, but creating something that could be built on transistor-like scale is a huge challenge. Now, boffins from the Technical University of Vienna, Japan’s National Institute of Informatics, and NTT’s Basic Research Labs are offering an architecture they reckon can be scaled up.

    What the researchers are offering, they believe, is a basic architecture they think would support a scalable quantum computer based on spins of nitrogen atoms in diamonds.

    The architecture uses nitrogen atoms that can occupy two spin states, injected into a diamond, with each nitrogen defect trapped in a two-mirror optical resonator. Optical fibres let the engineers couple photons to this quantum system, allowing them to work with it without destroying the nitrogen atom spins.

  13. Tomi Engdahl says:

    The Man Who Will Build Google’s Elusive Quantum Computer

    John Martinis is one of the world’s foremost experts on quantum computing, a growing field of science that aims to process information at super high speeds using strange physics of very tiny particles such as electrons and photons. And now, after years as a physics professor at the University of California Santa Barbara, he’s headed for Google.

    This week, the Google Quantum A.I. Lab announced that it hired Martinis and his Santa Barbara team to build a new breed of quantum computing hardware. Though Martinis will maintain his affiliation with UC Santa Barbara and continue to mentor his PhD students there, he will spend most of his time on his research at Google. The move proves that Google is serious about quantum computing, and given the company’s vast influence and deep pockets, it could provide a serious shot in the arm for quantum computer research as a whole.

    Martinis is among those questioning D-Wave’s claims. Last June, Science published a paper co-authored by Martinis and several other scientists concluding that D-Wave’s machines aren’t actually faster than normal laptops and desktops. But he’s no D-Wave hater. Martinis has been working with D-Wave’s machines for a few years now and says he has long been impressed with the work the company has done.

    Meanwhile, D-Wave has been mostly focused on trying to build machines with as many qubits as possible, but it hasn’t focused much on the problem of decoherence, Martinis says. By combining D-Wave’s work on achieving scale with their own work on stability, Martinis and his team think they can push the whole field of quantum computing further.

  14. Tomi Engdahl says:

    Google’s First Quantum Computer Will Build on D-Wave’s Approach

    Most quantum computing labs hope to slowly build universal “gate-model” machines that could perform as super-fast versions of today’s classical computers. Such labs have tended to cast a skeptical eye upon D-Wave, the Canadian company that has rapidly developed a more specialized type of quantum computing machine for lease to corporate customers such as Google and Lockheed Martin. In the latest twist, Google has hired an academic team of researchers to help build the first Google quantum computer based on the specialized D-Wave approach rather than on a universal gate-model blueprint.

    The Google announcement of its plan to build new quantum computing hardware coincided with its hiring of John Martinis, a professor of physics at the University of California, Santa Barbara, last week. Martinis has led an academic team in developing error correction techniques that can stabilize the quantum bits—called qubits—used by quantum computers to perform many simultaneous calculations by representing both 0 and 1 states at the same time.

  15. Tomi Engdahl says:

    The sound of silence: One excited atom is so quiet that the human ear cannot detect it
    Listen! Is this a Quantum Communications Leap?

    Boffins believe they have successfully demonstrated the sound a single atom makes when excited – even though it is completely inaudible to the human ear.

    According to a paper published in Science magazine on Thursday, researchers at the University of Columbia and Sweden’s Chalmers University of Technology “captured” the very soft sound.

    The discovery could eventually unlock the basic science for new quantum computing devices, reported Motherboard, which spoke to the paper’s co-author Göran Johansson.

    “Basically, when you excite the atom, it creates a sound, one phonon at a time, according to theory. It’s the weakest possible sound possible at the frequency [that it vibrates],” Johansson said.

    The artificial atom was created using a semiconducting circuit, such as those found in small quantum computers.

  16. Tomi Engdahl says:

    Tiny Graphene Drum for Future Quantum Computer and Sensor Technologies;Photonics

    Scientists from Netherlands’ Delft University of Technology have demonstrated that they can detect extremely small changes in position and forces on very small drums of graphene.

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  18. Tomi Engdahl says:

    Microsoft’s Quantum Mechanics

    MIT Technology Review has an excellent article summarizing the current state of quantum computing. It focuses on the efforts of Microsoft and Alcatel-Lucent’s Bell Labs to build stable qubits over the past few years.

    Microsoft’s Quantum Mechanics

    Can an aging corporation’s adventures in fundamental physics research open a new era of unimaginably powerful computers?

    Microsoft is now almost a decade into that project and has just begun to talk publicly about it. If it succeeds, the world could change dramatically. Since the physicist Richard Feynman first suggested the idea of a quantum computer in 1982, theorists have proved that such a machine could solve problems that would take the fastest conventional computers hundreds of millions of years or longer. Quantum computers might, for example, give researchers better tools to design novel medicines or super-efficient solar cells. They could revolutionize artificial intelligence.

    Progress toward that computational nirvana has been slow because no one has been able to make a reliable enough version of the basic building block of a quantum computer: a quantum bit, or qubit, which uses quantum effects to encode data. Academic and government researchers and corporate labs at IBM and Hewlett-Packard have all built them. Small numbers have been wired together, and the resulting devices are improving. But no one can control the physics well enough for these qubits to serve as the basis of a practical general-purpose computer.

  19. Tomi Engdahl says:

    First Demonstration of Artificial Intelligence On a Quantum Computer

    Machine learning algorithms use a training dataset to learn how to recognize features in images and use this ‘knowledge’ to spot the same features in new images. The computational complexity of this task is such that the time required to solve it increases in polynomial time with the number of images in the training set and the complexity of the “learned” feature.

    Now, a Chinese team has successfully implemented this artificial intelligence algorithm on a working quantum computer, for the first time.

    First Demonstration Of Artificial Intelligence On A Quantum Computer

    A Chinese team of physicists have trained a quantum computer to recognise handwritten characters, the first demonstration of “quantum artificial intelligence”

    Today, Zhaokai Li and pals at the University of Science and Technology of China in Hefei demonstrate machine learning on a quantum computer for the first time. Their quantum computer can recognise handwritten characters, just as humans can do, in what Li and co are calling the first demonstration of “quantum artificial intelligence”.

    To keep the experiment simple, the team trained their machine to recognise the difference between a handwritten 6 and a handwritten 9. The vectors representing 6s and 9s can then be compared in this feature space to work out how best to distinguish between them. In effect, the computer finds a hyperplane in the feature space that separates the vectors representing 6s from those representing 9s.

    That makes the task of recognising other 6s or 9s straightforward. For each new image of a character, the computer has to decide which side of the dividing line the vector sits.

  20. Tomi Engdahl says:

    Quantum Experiment Shows How Time ‘Emerges’ from Entanglement

    Time is an emergent phenomenon that is a side effect of quantum entanglement, say physicists. And they have the first experimental results to prove it

  21. Tomi Engdahl says:

    A leap into quantum computing

    This is the first in an occasional series that will describe some of the current work being done, and challenges in the field of quantum computing. I will also use this soap box to attempt to intrigue fellow electrical engineers into considering the field as a viable area of research, as many of the challenges currently plaguing the field fall under engineering disciplines.

  22. Tomi Engdahl says:

    Simon’s says quantum computing will work
    Boffins blast algorithm with half a dozen qubits

    One of the hard parts of quantum computing is turning laboratory qubits into a calculation of anything. Now, South African scientists claim they’ve tested a handful of qubits against a 20-year-old algorithm to demonstrate that yes, a quantum computer can run it “faster” than a classical machine.

    Regular readers of quantum-computing stories will know that D Wave has made controversial claims that it can solve some algorithms faster than classical computers using quantum annealing, but that those claims have become the subject of academic to-and-fro about their validity.

    The new claim isn’t anywhere near as startling: what the researchers from the University of KwaZulu-Natal in Durban say is that they’ve demonstrated that a six-qubit quantum computer solves what’s called Simon’s algorithm in fewer iterations than a classical computer would require.

    That’s not necessarily “faster”, since a multi-gigahertz processor can throw iterations up against the wall much faster than a quantum machine can at the moment. However, if / when quantum machines reach classical-like clocking (or rather the quantum computing equivalent thereof), the quantum machine would outpace its iterative competitor.

    Experimental Realization of a One-Way Quantum Computer Algorithm Solving Simon’s Problem

  23. Tomi Engdahl says:

    UK boffins: We’ll have an EMBIGGENED QUANTUM COMPUTER working in 5 YEARS
    Oxford boffins toil away on Q20:20 machine

    Oxford boffins have vowed to have the largest quantum computer ever made up and running within five years and help Blighty regain its place at the top of the tech world.

    The government has announced the creation of four “Quantum Technology Hubs” which will collaborate to build a small device called the Q20:20.

    Sadly, this won’t be a quantum laptop but a scalable machine which will open a “pathway to quantum computers big enough to tackle any problem”. It will be the largest quantum computer ever built, Oxford Uni claimed.

    “Quantum computing will enable users to solve problems that are completely intractable on conventional supercomputers. Meanwhile, quantum simulation provides a way to understand and predict the properties of complex systems such as advanced new materials or drugs, by using a quantum device to mimic the system under study,” said Professor Ian Walmsley, at Oxford Uni’s Department of Physics.

    The primary use of the Q20:20 will be to develop machine-learning techniques which can recognise patterns in data without a human having to get involved.

  24. Tomi Engdahl says:

    Quantum computing is so powerful it takes two years to understand what happened
    Boffins: ‘We factored 143′, ‘no, you factored 56,153′, which is bad news for crypto

    In 2012 a group of Chinese quantum physicists pulled off an acclaimed success in quantum-based factoring, running an adiabatic quantum algorithm for the number 143, at the time believed to be the largest number ever factored in a quantum computation.

    It now seems that paper, here, could have overlooked something: in a new paper at Arxiv, Nikesh Dattani and Nathaniel Bryans (Kyoto University and the University of Calgary, respectively, believe that the computation happened to also factor the numbers 3,599, 11,663 and 56,153.

    While even 56,153 is a tiny number compared to the kind of factorisation predicted by fans of Shor’s algorithm (and feared by spooks), it was accomplished using only four qubits – which means that the work can be reproduced and therefore validated on a classical computer without waiting an unreasonable time to test the work.

    Even better, from the researchers’ point of view, is that this represents a considerable jump compared to attempts to implement Shor’s algorithm (the first proposed use of a quantum computer for factorisation).

    So far, every shot at using a quantum computer to solve Shor’s algorithm could only be tested if the researcher already knew the answer

  25. Tomi Engdahl says:

    CommBank throws AU$5 MEELLION at UNSW quantum computer lab
    Because everyone wants their bank balance stored as a superposition

    Australia’s Commonwealth Bank has decided to make a AU$5 million donation to the University of New South Wales’ Centre for Quantum Computation and Communication Technology.

    The money is intended to help two projects, namely an effort to “demonstrate entanglement in a scalable silicon based quantum computing architecture and then to coherently transport quantum information to create ‘flying qubits’ within the computer.”

  26. Tomi Engdahl says:

    A Faster Way To Make Quantum Computing Chips

    Optics researchers from INRS-EMT in Quebec, Canada have developed a new method of generating photon pairs — tiny entangled particles of light — that are small enough to fit onto a computer chip.

    The new power-efficient approach could enable next-generation quantum computers and optical communication technologies.

    Generating photon pairs on demand is only a recent breakthrough, but it’s important for creating certain computer networks that can process quantum information. Methods of photon polarization — the direction in which an electric field associated with a photon oscillates — thus far only generate photons with same polarization as the laser beam used to pump the device. These states must be mixed afterward to create cross-polarization. The new method shortens the process by directly generating cross-polarized photon pairs, from devices less than one square millimeter in area.

    To generate cross-polarized photons, the research team used two laser beams, one polarized vertically, the other horizontally. A micro-ring resonator (a type of optical cavity that’s anywhere from 10 – 100 micrometers) prevented the two beams’ “classical effects” from destroying the photons’ fragile quantum states, while at the same time amplifying quantum processes.

  27. Tomi Engdahl says:

    Diamonds are a power IC’s best friend

    Synthetic diamond is now being tested for quantum-based applications such as secure quantum communication, quantum computing, and magnetic/electric field sensing. Quantum applications use the exciting world of quantum physics to perform operations, which would not be possible in systems adhering to classical physics.

    Synthetic diamond has significant advantages over competitive materials because the quantum properties of the defects it hosts can be manipulated and probed at room temperature.

  28. Tomi Engdahl says:

    Quantum Entanglement Now On-a-Chip
    Breakthrough 20 micron enables uncrackable encryption

    Quantum computing promises to revolutionize future computers, enabling pint-sized hardware to outperform room-filing supercomputers, plus offers uncrackable encryption that foils all hackers no matter how skillful they are. The missing piece of the quantum puzzle was called “spooky action at a distance” by Einstein, namely a reliable source of entangled photons who mirror each others’ state no matter how far apart on standard CMOS silicon chips.

    Now Italian scientists at the Università degli Studi di Pavia, in cooperation with the University of Glasgow and the University of Toronto, claim to have surmounted this last engineering hurdle.

    “The idea is that pumping laser light inside a tiny ring enhances the probability of two photons interacting. We therefore decided that this enhancement could be used, in particular, for the production of entangled photon pairs,” professor Daniele Bajoni at the Università degli Studi di Pavia told EE Times. “In previous works, we discovered that confining light inside a ring resonator greatly enhances the interaction between light and matter, but our new results were realized by design, not by chance.”

    “The most typical algorithm for quantum cryptography using entanglement is the so-called Eckert protocol. In essence two parties (generally named Alice and Bob) exchange a set of entangled photon pairs, let us say idler photons are sent to Alice and signal photons are sent to Bob. Alice performs certain measurements on her photons, obtaining random results (let us say 1100101). If Bob performs the correct measurements on his photons, because of the entanglement, he will get the same string of random bits as Alice. The two can then use this string of random bits to encrypt signals to be sent on normal channels,” Bajoni told us. “If someone eavesdrops the exchange of entangled photons between Alice and Bob, this action will change the properties of the photons, so that Alice and Bob can know if there is an eavesdropper: this makes the communication intrinsically secure.”

  29. Tomi Engdahl says:

    Jordan Novet / VentureBeat:
    Quantum computing company D-Wave raises an additional $23.1M, bringing total to $138.7M

    D-Wave keeps dreaming of quantum computers everywhere, takes $23.1M more

    D-Wave Systems, a company building what it calls quantum computers, is announcing today that it has taken on around $23.1 million, or $29 million in Canadian dollars, in additional funding.

    Burnaby, British-Columbia-based D-Wave claims its hardware is capable of quantum computing.

    Some researchers have wondered if D-Wave’s machines really do achieve a quantum state. Even so, D-Wave has landed some prominent deals in the past couple of years. In 2013, Lockheed Martin, D-Wave’s first customer, shelled out for an upgrade to a D-Wave Two computer. That same year, Google and NASA announced that they had picked up a D-Wave Two system for a joint project, the Quantum Artificial Intelligence Lab, at NASA’s Ames Research Center.

    The new money will help “accelerate development of D-Wave’s quantum hardware and software and expand the software application ecosystem,” according to a statement from the company. Meanwhile, Microsoft has been incubating a quantum computing initiative of its own on the University of California, Santa Barbara campus.

  30. Tomi Engdahl says:

    Quantum computers have failed. So now for the science
    Bouncing oil droplets reveal slippery truth behind the magical promises

    I am a heretic. There, I’ve said it. My heresy? I don’t believe that quantum computers can ever work.

    I’ve been a cryptographer for over 20 years and for all that time we’ve been told that sooner or later someone would build a quantum computer that would factor large numbers easily, making our current systems useless.

    However, despite enormous amounts of money spent by research councils and government agencies, the things are stuck at three qubits. Factoring 15 is easy; 35 seems too hard. A Canadian company has started selling computers they claim are quantum; scientists from Google and NASA said they couldn’t observe any quantum speed-up.

    Classical musings

    Most physicists nowadays are sceptical that quantum mechanics can arise from an underlying classical system: see for example the Wired article on bouncing droplets. The reason for this, and the argument for quantum computing, hinges on the “Bell tests”. Let me explain.

    In 1935, Einstein had argued that quantum mechanics could not be the whole story, because if two electrons were generated by the same atomic decay, then quantum mechanics tells us that their states are “entangled”, which means that they can be described by a single wave function and thus will remain correlated until one of them interacts with another particle.

    Wave of correlation

    The secret is that the magnetic line of force already sets up a correlation along its length, and this provides the secret sauce. Just as in the droplet experiment, if you have an existing long-range order, then quantum mechanics can arise from an underlying classical model. In particular, we can model the photon as a wave in a classical fluid that obeys Maxwell’s equations and is in quantitative agreement with the predictions of quantum mechanics as measured in the Bell tests.

    We’re still some way off being able to derive the whole of the Standard Model starting from an underlying classical spacetime. But there is now a whole discipline, called emergent quantum mechanics, which searches for just such models, and some are rather innovative.

    Our paper shows that you don’t need multiple universes to explain the weirdness of quantum behaviour, just some form of long-range order in the universe, whether that comes from an underlying computational mesh, the order parameter of a superfluid or perhaps simply from the magnetic fields that pervade the observable universe.

    And if reality is analogue all the way down, then quantum computers are just analogue computers, so their failure to deliver magical results is unsurprising. In fact, we’d rather see it as evidence that the emergent quantum mechanics research community may be on the right track. The magic has failed; now let’s get on with the science

  31. Tomi Engdahl says:

    Quantum of Suspicion: Despite another $29m, D-Wave doubts remain
    What exactly is company offering?

    Controversial quantum computing venture D-Wave Systems has scooped $29m in lovely fresh cash, courtesy of investors, despite lingering doubts about whether what it offers can be considered “quantum”.

    This is D-Wave’s tenth round of funding from 14 investors, bringing total investments to fairly hefty $174m.

    D-Wave didn’t identify the source of its latest infusion, but emphasised the line-up included one “large institutional investor” among others.

    D-Wave claims it is the first quantum computing company, with customers including Lockheed Martin, Google and NASA. However, there’s considerable debate and uncertainty about whether what D-Wave offers can actually be considered quantum.

    Scientists and experts in the field of physics have disputed whether what D-Wave has can accurately be called quantum computing.

  32. Tomi Engdahl says:

    The Near-Term Future of Quantum Computing? Analog Simulations

    Contrary to what you may have ​heard, progress in quantum computing is slow and painful. While there are papers and studies out every week describing some new technology that could have a quantum computing implication at some theoretical future point—together reinforcing the impression that we are really, truly almost there—they usually have less to do with the thing itself: a quantum computer.

  33. Tomi Engdahl says:

    IBM Shows Off a Quantum Computing Chip

    A new superconducting chip made by IBM demonstrates a technique crucial to the development of quantum computer

    A superconducting chip developed at IBM demonstrates an important step needed for the creation of computer processors that crunch numbers by exploiting the weirdness of quantum physics. If successfully developed, quantum computers could effectively take shortcuts through many calculations that are difficult for today’s computers.

    IBM’s new chip is the first to integrate the basic devices needed to build a quantum computer, known as qubits, into a 2-D grid. Researchers think one of the best routes to making a practical quantum computer would involve creating grids of hundreds or thousands of qubits working together. The circuits of IBM’s chip are made from metals that become superconducting when cooled to extremely low temperatures. The chip operates at only a fraction of a degree above absolute zero.

    However, qubits also suffer from a second kind of error known as a phase flip, where a qubit’s superposition state becomes distorted. Qubits can only detect that in other qubits if they are working together in a 2-D array

    A paper published today details how IBM’s chip with four qubits arranged in a square can detect both bit and phase flips. One pair of qubits is checked for errors by the other pair of qubits. One of the pair doing the checking looks for bit flips and the other for phase flips.

    “This is a stepping stone toward demonstrating a larger square,” says Gambetta. “There will be other challenges that emerge as the square gets bigger, but it looks very optimistic for the next few steps.”

  34. Tomi Engdahl says:

    Graphene is the darling material for next generation computing, and now researchers have found a way to use it in future quantum computers as well.

    “Valleytronics”–mimicking the name of its rival spintronics–may yield a new encoding technique for quantum bits (qubits) traveling like waves in valleys of dual-layer graphene. Instead of encoding a qubit’s quantum information on the spin of an electron–as in spintronics–valleytronics encodes qubits with the momentum imparted by an electron-wave traveling in numbered valleys along the domain walls in dual-layer graphene. Separately, Georgia Tech and Honeywell have micro-fabricated an ion trap architecture aimed at increasing the density of qubits in future quantum computers.

    “Qubits can be valley polarized along the topologically protected one-dimensional electron conducting channels at the domain walls of bilayer graphene,” professor Feng Wang told EE Times. “1D valley-polarized conducting channels in lattice of 2D graphene opens up new opportunities for future quantum computers.” He performed the work with postdoctoral researcher Zhiwen Shi and doctoral candidate Long Ju.

  35. Tomi Engdahl says:

    Is D-Wave a Quantum Computer?
    Critics charge its not a “real” QC

    Recently I had to explain to a reader why critics say that D-Wave’s so-called quantum computer was not a “real” quantum computer, the answer for which he accepted on my authority. However, the question kept nagging me in the back on my mind “why” D-Wave markets what it calls a quantum computer if it is not for real. To get to the bottom of it, I asked Jeremy Hilton, vice president of processor development of D-Wave Systems, Inc. (Burnaby, British Columbia, Canada) about why critics keep saying its quantum computer is not for real. He also revealed details about D-Wave’s next generation quantum computer.

    “The Holy Grail of quantum computing to build a ‘universal’ quantum computer—one that can solve any computational problem—but at a vastly higher speed that today’s computers,” Hilton told EE Times. “That’s the reason some people say we don’t have a ‘real’ quantum computer—because D-Wave’s is not a ‘universal’ computer.”

    D-Wave’s quantum computer, rather, only solves optimization problems, that is ones that can be expressed in a linear equation with lots of variables each with its own weight (the number that is multiplied times each variable). Normally, such linear equations are very difficult to solve for a conventional ‘universal’ computer, taking lots of iterations to find the optimal set of values for the variables. However, with D-Wave’s application-specific quantum computer, such problems can be solved in a single cycle.

    “We believe that starting with an application-specific quantum processor is the right way to go—as a stepping stone to the Holy Grail—a universal quantum computer,”

    D-Wave’s current quantum processor has 512 qubits, allowing it to solve optimization problems with less than or equal to 512 variables in single machine cycle. To solve qubit-based optimization problems, D-Wave uses a different model for computation than a universal computer, called the adiabatic (occurring without loss or gain of heat) instead of the approach take by everyone working toward a universal quantum computer—the normal gates-based model when qubits are processed in the quantum computer in a manner similar to conventional computers.

    “The goal of the adiabatic method is to keep the qubits in their lowest energy state, which is where they are at the beginning and end of a optimization problem,”

    Those working toward a universal quantum computer today are obsessed with error correction methods—using up to thousands of qubits just to ensure that the superposition of values in a quantum state (part 0 and part 1) is maintained accurately throughout all of its calculations. With the adiabatic method, Hilton claimed, you don’t need error correction because the qubits naturally relax into their lowest energy state.

    “I know testing of the D-Wave hardware has been mixed, but I understand why large companies are investing in it anyway,” Battista told us.

  36. Tomi Engdahl says:

    Quantum computing is “closer than you think” – now it has an OS

    Cambridge Quantum Computing (“CQCL”; Cambridge, UK) has announced that it has developed an operating system for Quantum Computers.

    t|ket> a unique quantum computing operating system; thus far, it has only run on a simulation of a quantum computer, which itself runs on a proprietary custom designed high speed super computer, also built by CQCL, in order to simulate a quantum processor.

    The company stated, “CQCL is at the forefront of developing an operating system that will allow users to harness the joint power of classical super computers alongside quantum computers. The development of t|ket> is a major milestone.

    “Quantum computing will be a reality much earlier than originally anticipated. It will have profound and far-reaching effects on a vast number of aspects of our daily lives.”

    CQCL develops tools for the commercialisation of quantum computers by understanding quantum protocols and also quantum algorithms. In the coming period as quantum devices become more prevalent, the focus of CQCL’s activity is the development of algorithms and source code.

  37. Tomi Engdahl says:

    D-Wave promises chip that could SEARCH THE WHOLE UNIVERSE
    1k-qubit chip late, still controversial

    The 1,000-qubit chip promised by D-Wave last year has landed.

    The 1,000-plus-qubit device was originally planned for the end of 2014.

    The doubling of qubits over its previous processor, the company says, gives it a 21000 search space – not only dwarfing the previous 2512 search space, but containing “far more possibilities than there are particles in the observable universe”.

    The processors also contain 128,000 Josephson tunnel junctions, the outfit says, which it reckons are “the most complex superconductor integrated circuits ever successfully yielded”.

    Just what that means out in the world of computing, we’ll have to wait and see. The Register expects the new processor will result in yet more is-it-quantum academic debate in paper and counter-paper (Arxiv should be worth watching) once researchers get their hands on test systems.

    To get the 1,000 qubits – actually 1,152 – the company is fabricating a 2,048 qubit “fabric”.

    It then has to run each device through a qualification process to see which qubits are within the performance range

  38. Tomi Engdahl says:

    Quantum Highway Frictionless
    Cheaper materials encode spin

    Quantum computer builders use exotic materials that are not commercially viable for the mass market — from super-cooled superconductors to tubes full of gas ions cooled by lasers. All this may be about to change.

    Now researchers have found that by combining two relatively cheap and plentiful solid-state materials (namely ferromagnets and topological insulators), they posit that frictionless quantum highways can be constructed that conduct and switch qubit flows in a way that mimics transistors.

    “Ferromagnetism alters the electronic structure of a topological insulator by opening up a mini-gap within the bulk bandgap,” said Cui-zu Chang, a post-doctoral researcher working in the lab of Massachusetts Institute of Technology (MIT) Professor Ju Li, in an interview with EE Times. “In addition, it reaches a quantum phase transition called a ‘quantum anomalous Hall state,’ where a dissipation-less chiral conducting channel opens at the edge of the sample exactly at zero magnetic field.”

    As a result, these unique properties at the interface of a ferromagnetic material and a topological insulator could be the key to producing the “perfect quantum switch” with frictionless transmission of qubits in a material that is relatively inexpensive to construct and requires even less energy to operate.

  39. Tomi Engdahl says:

    Larry Dignan / ZDNet:
    Intel will invest $50M in quantum computing research in Delft University of Technology and Dutch Organisation for Applied Research

    Intel invests $50 million in quantum computing effort

    Intel is the latest technology giant to invest in quantum computing research. Quantum computing, years away from commercialization, is supposed to be a huge leap forward.

    Intel said Thursday that it will invest $50 million and provide engineering resources to the Delft University of Technology and TNO, the Dutch Organisation for Applied Research, in an effort to advance quantum computing.

    Quantum computing promises multiple breakthrough and the possibility of new applications. Quantum computers use quantum bits, or qubits, which can exist in multiple states and operate in parallel. Quantum computers are expected to replace the ones powered by transistors and binary digits today.

    Intel’s investment could popularize the notion of quantum computing, which is years from going commercial. IBM has been among the largest tech players in the quantum computer space. IBM is investing billions of dollars in research on developing processors that could power quantum computers. See: IBM claims another step toward quantum computing | IBM to invest $3 billion in next-gen, ’7nm and beyond’ chips

    Other entities ranging from Google to NASA are also chasing quantum computing.

    The chip giant said it can contribute manufacturing and architecture knowhow to quantum computing research.

    For Intel, the bet on quantum computer is a way to participate in the future and keep the company relevant.

  40. Tomi Engdahl says:

    Cryptographers Brace For Quantum Revolution

    An article in Scientific American discusses the actions needed to address the looming advent of quantum computing and its ability to crack current encryption schemes. Interesting tidbits from the article: “‘I’m genuinely worried we’re not going to be ready in time,’ says Michele Mosca, co-founder of the Institute for Quantum Computing (IQC) at the University of Waterloo.

    Online security braces for quantum revolution
    Encryption fix begins in preparation for arrival of futuristic computers.

    It is an inevitability that cryptographers dread: the arrival of powerful quantum computers that can break the security of the Internet. Although these devices are thought to be a decade or more away, researchers are adamant that preparations must begin now.

    Computer-security specialists are meeting in Germany this week to discuss quantum-resistant replacements for today’s cryptographic systems — the protocols used to scramble and protect private information as it traverses the web and other digital networks. Although today’s hackers can, and often do, steal private information by guessing passwords, impersonating authorized users or installing malicious software on computer networks, existing computers are unable to crack standard forms of encryption used to send sensitive data over the Internet.

  41. Tomi Engdahl says:

    Quantum Computing Kills Encryption

    Imagine a world where the most widely-used cryptographic methods turn out to be broken: quantum computers allow encrypted Internet data transactions to become readable by anyone who happened to be listening. No more HTTPS, no more PGP. It sounds a little bit sci-fi, but that’s exactly the scenario that cryptographers interested in

    If you take the development of serious quantum computing power as a given, all of the encryption methods based on factoring primes or doing modular exponentials, most notably RSA, elliptic curve cryptography, and Diffie-Hellman are all in trouble. Specifically, Shor’s algorithm, when applied on a quantum computer, will render the previously difficult math problems that underlie these methods trivially easy almost irrespective of chosen key length. That covers most currently used public-key crypto and the key exchange that’s used in negotiating an SSL connection.

    All is not doom and gloom, however. There are families of public-key algorithms that aren’t solved by Shor’s algorithm or any of the other known quantum algorithms,

    Strong symmetric ciphers, algorithms that use the same key for encryption and decryption (AES, Blowfish, etc.) will also be easier to crack with quantum computers, but only by roughly a factor of two. So if you are happy with AES-128 today, you’ll be happy with AES-256 in a quantum-computing future.

    Quantum computing is still in its infancy, but it may already be time to start worrying about your data today.

    How Soon?

    In short, it looks like the quantum computing apocalypse is coming, but there’s current research going on and hopefully we’ll get some solid procedures in place in time. Nobody really knows how long we’ve got until quantum computers will be able to handle real-world cryptanalysis, but the numbers that the post-quantum folks toss around are in the ten-to-thirty year range.

    In particular, McEliece cryptosystems come out looking like a good alternative to the current public-key infrastructure. Instead of relying on factoring large numbers, a McEliece system hides your data by first wrapping it up with an error-correcting code (ECC) and then deliberately adding noise to it. Quantum computers, incidentally, turn out not to be very useful in computing some types of ECCs, which is the whole point of this operation.


    Practical quantum computing is probably ten to thirty years away. When it comes, whatever you’ve encrypted using today’s standard public-key encryption systems will be trivial to decrypt. Anyone storing your (or your government’s) data now will likely be able to read it when today’s toddler is enrolling in college. And you can bet that a good part of the rationale for the NSA’s recommendation about transitioning away from susceptible technologies is that they know of some large, well-funded government agencies who are doing that storing on a large scale today.

    Practical quantum computing is probably ten to thirty years away. When it comes, whatever you’ve encrypted using today’s standard public-key encryption systems will be trivial to decrypt. Anyone storing your (or your government’s) data now will likely be able to read it when today’s toddler is enrolling in college. And you can bet that a good part of the rationale for the NSA’s recommendation about transitioning away from susceptible technologies is that they know of some large, well-funded government agencies who are doing that storing on a large scale today.

  42. Tomi Engdahl says:

    Crucial hurdle overcome in quantum computing

    A team of Australian engineers has built a quantum logic gate in silicon for the first time, making calculations between two qubits of information possible – and thereby clearing the final hurdle to making silicon quantum computers a reality.

    A team of Australian engineers has built a quantum logic gate in silicon for the first time, making calculations between two qubits of information possible – and thereby clearing the final hurdle to making silicon quantum computers a reality.

    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.

    In classical computers, data is 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.

    “If quantum computers are to become a reality, the ability to conduct one- and two-qubit calculations are essential,”

    “Despite this enormous global interest and investment, quantum computing has – like Schrödinger’s cat – been simultaneously possible (in theory) but seemingly impossible (in physical reality),” said Professor Mark Hoffman, UNSW’s Dean of Engineering.

    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

  43. Tomi Engdahl says:

    D-Wave heads for New Mexico
    Los Alamos kicks the quantum tyre

    The Los Alamos National Laboratory has become the latest organisation to give quantum annealing a whirl, with D-Wave announcing that the facility will take delivery of its thousand-qubit 2X system.

    The national security research outfit will be collaborating with the Department of Energy and “selected university partners” to put the is-it-isn’t-it-quantum computer through its paces.

    The machine is due for delivery in early 2016.

    The D-Wave release quotes director of the lab’s Weapons Physics Directorate, Mark Anderson, as saying “we need to investigate new technologies to support our mission.

    “Researching and evaluating quantum annealing as the basis for new approaches to address intractable problems is an essential and powerful step, and will enable a new generation of forward thinkers to influence its evolution in a direction most beneficial to the nation”, he added.

    In other words, conventional supercomputers can only do so much nuke-simulation, and if quantum annealing works as it says on the box, it’ll help give the US a shiny new arsenal without having to actually blow things up.

  44. Tomi Engdahl says:

    Spy Agencies Fund IBM’s Quantum Computing Research

    The US Intelligence Advanced Research Projects Activity (IARPA) program has notified IBM that it will award the company’s scientists a major multi-year research grant to advance the building blocks for a universal quantum computer. IBM announced the grant on Dec. 8.

    IBM is not disclosing further terms of the award because “it is subject to completion of final contract negotiations,” according to the company.

    IARPA is the research arm of the 17-member U.S. Intelligence Community, which includes the CIA. We think a universal quantum computer could be great at addressing intelligence challenges such as deciphering encrypted data. IBM has other use-cases in mind.

    Spy Agencies Fund IBM’s Quantum Computing Research

    Big Blue gets a multi-year grant from the US intelligence community for the development of quantum computing technology. A universal quantum computer could tackle challenges such as safeguarding against cyberattacks and speeding up medical R&D.

    IBM Awarded IARPA Grant to Advance Research Towards a Universal Quantum Computer
    IBM scientists will focus on building the first logical quantum bit

    YORKTOWN HEIGHTS, N.Y., Dec. 8, 2015 /PRNewswire/ — IBM (NYSE: IBM) announced today that the U.S. Intelligence Advanced Research Projects Activity (IARPA) program has notified IBM that it will award its scientists a major multi-year research grant to advance the building blocks for a universal quantum computer.

    A universal quantum computer uses quantum mechanics to process massive amounts of data and perform computations in powerful new ways not possible with today’s conventional computers. This type of leap forward in computing could one day shorten the time to discovery for life-saving cancer drugs to a fraction of what it is today; unlock new facets of artificial intelligence by vastly accelerating machine learning; or safeguard cloud computing systems to be impregnable from cyber-attack.
    IBM Infographic – The three known types of quantum computing and their applications, generality, and computational power.

    IBM Infographic – The three known types of quantum computing and their applications, generality, and computational power.

    Earlier this year, IBM scientists demonstrated critical breakthroughs to detect quantum errors by combining superconducting quantum bits (qubits) in lattices on computer chips – and whose quantum circuit design is the only physical architecture that can scale to larger dimensions.

    The award is funded under the Logical Qubits (LogiQ) program of IARPA led by Dr. David Moehring. The LogiQ Program seeks to overcome the limitations of current quantum systems by building a logical qubit from a number of imperfect physical qubits.

    IBM Scientists Achieve Critical Steps to Building First Practical Quantum Computer
    Two Milestones Overcome Obstacles to a Working System

    Yorktown Heights, N.Y., – 29 Apr 2015: IBM (NYSE: IBM) scientists today unveiled two critical advances towards the realization of a practical quantum computer. For the first time, they showed the ability to detect and measure both kinds of quantum errors simultaneously, as well as demonstrated a new, square quantum bit circuit design that is the only physical architecture that could successfully scale to larger dimensions.

    With Moore’s Law expected to run out of steam, quantum computing will be among the inventions that could usher in a new era of innovation across industries. Quantum computers promise to open up new capabilities in the fields of optimization and simulation simply not possible using today’s computers. If a quantum computer could be built with just 50 quantum bits (qubits), no combination of today’s TOP500 supercomputers could successfully outperform it.

    The IBM breakthroughs, described in the April 29 issue of the journal Nature Communications (DOI: 10.1038/ncomms7979), show for the first time the ability to detect and measure the two types of quantum errors (bit-flip and phase-flip) that will occur in any real quantum computer. Until now, it was only possible to address one type of quantum error or the other, but never both at the same time. This is a necessary step toward quantum error correction, which is a critical requirement for building a practical and reliable large-scale quantum computer.

    IBM’s novel and complex quantum bit circuit, based on a square lattice of four superconducting qubits on a chip roughly one-quarter-inch square, enables both types of quantum errors to be detected at the same time. By opting for a square-shaped design versus a linear array – which prevents the detection of both kinds of quantum errors simultaneously – IBM’s design shows the best potential to scale by adding more qubits to arrive at a working quantum system.

  45. Tomi Engdahl says:

    A Turning Point For Quantum Computing

    Quantum computing is moving from theory and experimentation into engineering and applications.

    But now that quantum computing is going mainstream, it is incumbent on businesses and governments to understand its potential, for universities to beef up their teaching programs in quantum computing and related subjects and for students to become aware of promising new career paths.

    Quantum computing got its start at a smaller, now famous, conference in 1981, jointly hosted by IBM and MIT, on the physics of computing.

  46. Tomi Engdahl says:

    Shmoocon 2016: Computing In A Post Quantum World

    There’s nothing more dangerous, so the cryptoheads say, than quantum computing. Instead of using the state of a transistor to hold the value of a bit as in traditional computers, quantum computers use qubits, or quantum information like the polarization of a photon. According to people who know nothing about quantum computers, they are the beginning of the end, the breaking of all cryptography, and the Rise of the Machines. Lucky for us, [Jean-Philippe Aumasson] actually knows a thing or two about quantum computers and was able to teach us a few things at his Shmoocon talk this weekend, “Crypto and Quantum and Post Quantum”

    The astute reader would question the fact that quantum computers may never be built. After all, D-Wave is selling quantum computers to Google, Lockheed, and NASA. These are not true quantum computers. Even if they’re 100 Million times faster than a PC, they’re only faster for one very specific algorithm.

    As far as true quantum computers go, the largest that has every been manufactured only contain a handful of qubits. To crack RSA and the rest of cryptography, millions of qubits are needed. Some algorithms require quantum RAM, which nobody knows how to build. Why then is quantum computing so scary? RSA, ECC, Diffie-Hellman, PGP, SSH and Bitcoin would die overnight if quantum computers existed.

  47. Tomi Engdahl says:

    Quantum computing gets a bit more real: implications for encryption

    Researchers at MIT and the University of Innsbruck (Austria) have built a quantum computer that manipulates the states of just five atoms to solve the find-the-prime-factors-of-a-number problem; while the actual problem solved – factorising the number 15 – appears trivial, the scheme they have devised is in principle scalable and, in time, may begin to erode the basis of prime-factors-based encryption schemes; the key aspect of the announcement lies in scalability.

    The prime factors of the ‘minimal case’ of the number 15 are obvious; 3 and 5. A larger number, say, below 100, may take some pen and paper. An even larger number, with hundreds of digits, can take years to factor, using hundreds of classical computers operating in parallel.

    The difficulty of finding the prime factors of a large number underpins the key-based, secure encryption in universal use today. It has long been realised that in principle, a quantum computer has the potential to attack the problem. A computer that could manipulate the states of hundreds of atoms simultaneously might quickly factor very large numbers.

    Now, in a paper published in the journal Science , the researchers report that they have designed and built a quantum computer from five atoms in an ion trap. The computer uses laser pulses to carry out Shor’s algorithm on each atom, to correctly factor the number 15.

    Realization of a scalable Shor algorithm

  48. Tomi Engdahl says:

    Canny Canadian PM schools snarky hack on quantum computing
    If only US legislators had the same skills

    Video The Canadian Prime Minister Justin Trudeau has humiliated a Canadian journalist who assumed he was clueless about quantum computing.

    “OK, quite simply, normal computers work by…” Trudeau started before the room erupted. “No, no, don’t interrupt me, when you walk out of here you will know more, well no, some of you will know far less about quantum computing,” he said.

    “Normal computers work, either there’s power going through a wire or not. It’s one or a zero. They’re binary systems,” the PM explained.

    “A quantum state can be much more complex than that because, as we know, things can be both particle and wave at the same time, and the uncertainty around quantum states allows us to encode more information into a much smaller computer.”

    As explanations go, it’s a pretty good one.

    If only American politicians displayed the same knowledge.

  49. Tomi Engdahl says:

    Three-bit quantum gate a step closer to universal quantum computer
    Photons as building blocks for AND, OR, XOR and NOT

    Quantum research boffins in Australia have demonstrated one of computing’s universal gates, the Fredkin gate, operating with qubits instead of bits.

    The Fredkin gate – described here at Wikipedia – is a reversible three-bit gate that can be used to construct AND, OR, XOR and NOT functions. If the first of the three bits is a 1, the last two bits are swapped (0 to 1, or 1 to 0); if the first bit is a zero, they’re not (also called a controlled SWAP function).

    In the experiment conducted by researchers from Australia’s Griffith University and University of Queensland, the gate swaps the quantum states of two qubits, based on the value of the control.

    As they note in their open-access paper at Science Advances, the Fredkin gate is useful to quantum computing, error correction, cryptography and measurement.

    In quantum cryptography, for example, direct comparison of two sets of qubits is useful for verifying that two digital signatures are the same.


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