# Category Archives: Quantum Computer

## Quantum computer | computer science | Britannica.com

Quantum computer, device that employs properties described by quantum mechanics to enhance computations.

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computer: Quantum computing

According to quantum mechanics, an electron has a binary (two-valued) property known as spin. This suggests another way of representing a bit of information. While single-particle information storage is attractive, it would be difficult to manipulate. The fundamental idea of quantum computing, however,

As early as 1959 the American physicist and Nobel laureate Richard Feynman noted that, as electronic components begin to reach microscopic scales, effects predicted by quantum mechanics occurwhich, he suggested, might be exploited in the design of more powerful computers. In particular, quantum researchers hope to harness a phenomenon known as superposition. In the quantum mechanical world, objects do not necessarily have clearly defined states, as demonstrated by the famous experiment in which a single photon of light passing through a screen with two small slits will produce a wavelike interference pattern, or superposition of all available paths. (See wave-particle duality.) However, when one slit is closedor a detector is used to determine which slit the photon passed throughthe interference pattern disappears. In consequence, a quantum system exists in all possible states before a measurement collapses the system into one state. Harnessing this phenomenon in a computer promises to expand computational power greatly. A traditional digital computer employs binary digits, or bits, that can be in one of two states, represented as 0 and 1; thus, for example, a 4-bit computer register can hold any one of 16 (24) possible numbers. In contrast, a quantum bit (qubit) exists in a wavelike superposition of values from 0 to 1; thus, for example, a 4-qubit computer register can hold 16 different numbers simultaneously. In theory, a quantum computer can therefore operate on a great many values in parallel, so that a 30-qubit quantum computer would be comparable to a digital computer capable of performing 10 trillion floating-point operations per second (TFLOPS)comparable to the speed of the fastest supercomputers.

During the 1980s and 90s the theory of quantum computers advanced considerably beyond Feynmans early speculations. In 1985 David Deutsch of the University of Oxford described the construction of quantum logic gates for a universal quantum computer, and in 1994 Peter Shor of AT&T devised an algorithm to factor numbers with a quantum computer that would require as few as six qubits (although many more qubits would be necessary for factoring large numbers in a reasonable time). When a practical quantum computer is built, it will break current encryption schemes based on multiplying two large primes; in compensation, quantum mechanical effects offer a new method of secure communication known as quantum encryption. However, actually building a useful quantum computer has proved difficult. Although the potential of quantum computers is enormous, the requirements are equally stringent. A quantum computer must maintain coherence between its qubits (known as quantum entanglement) long enough to perform an algorithm; because of nearly inevitable interactions with the environment (decoherence), practical methods of detecting and correcting errors need to be devised; and, finally, since measuring a quantum system disturbs its state, reliable methods of extracting information must be developed.

Plans for building quantum computers have been proposed; although several demonstrate the fundamental principles, none is beyond the experimental stage. Three of the most promising approaches are presented below: nuclear magnetic resonance (NMR), ion traps, and quantum dots.

In 1998 Isaac Chuang of the Los Alamos National Laboratory, Neil Gershenfeld of the Massachusetts Institute of Technology (MIT), and Mark Kubinec of the University of California at Berkeley created the first quantum computer (2-qubit) that could be loaded with data and output a solution. Although their system was coherent for only a few nanoseconds and trivial from the perspective of solving meaningful problems, it demonstrated the principles of quantum computation. Rather than trying to isolate a few subatomic particles, they dissolved a large number of chloroform molecules (CHCL3) in water at room temperature and applied a magnetic field to orient the spins of the carbon and hydrogen nuclei in the chloroform. (Because ordinary carbon has no magnetic spin, their solution used an isotope, carbon-13.) A spin parallel to the external magnetic field could then be interpreted as a 1 and an antiparallel spin as 0, and the hydrogen nuclei and carbon-13 nuclei could be treated collectively as a 2-qubit system. In addition to the external magnetic field, radio frequency pulses were applied to cause spin states to flip, thereby creating superimposed parallel and antiparallel states. Further pulses were applied to execute a simple algorithm and to examine the systems final state. This type of quantum computer can be extended by using molecules with more individually addressable nuclei. In fact, in March 2000 Emanuel Knill, Raymond Laflamme, and Rudy Martinez of Los Alamos and Ching-Hua Tseng of MIT announced that they had created a 7-qubit quantum computer using trans-crotonic acid. However, many researchers are skeptical about extending magnetic techniques much beyond 10 to 15 qubits because of diminishing coherence among the nuclei.

Just one week before the announcement of a 7-qubit quantum computer, physicist David Wineland and colleagues at the U.S. National Institute for Standards and Technology (NIST) announced that they had created a 4-qubit quantum computer by entangling four ionized beryllium atoms using an electromagnetic trap. After confining the ions in a linear arrangement, a laser cooled the particles almost to absolute zero and synchronized their spin states. Finally, a laser was used to entangle the particles, creating a superposition of both spin-up and spin-down states simultaneously for all four ions. Again, this approach demonstrated basic principles of quantum computing, but scaling up the technique to practical dimensions remains problematic.

Quantum computers based on semiconductor technology are yet another possibility. In a common approach a discrete number of free electrons (qubits) reside within extremely small regions, known as quantum dots, and in one of two spin states, interpreted as 0 and 1. Although prone to decoherence, such quantum computers build on well-established, solid-state techniques and offer the prospect of readily applying integrated circuit scaling technology. In addition, large ensembles of identical quantum dots could potentially be manufactured on a single silicon chip. The chip operates in an external magnetic field that controls electron spin states, while neighbouring electrons are weakly coupled (entangled) through quantum mechanical effects. An array of superimposed wire electrodes allows individual quantum dots to be addressed, algorithms executed, and results deduced. Such a system necessarily must be operated at temperatures near absolute zero to minimize environmental decoherence, but it has the potential to incorporate very large numbers of qubits.

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Quantum computer | computer science | Britannica.com

## IBMs new quantum computer is a symbol, not a breakthrough

In the grueling race to build a practical quantum computer, tech companies are keeping their spirits up by loudly cheering every milestone no matter how small. One of the most vocal competitors is IBM, which today at CES unveiled the IBM Q System One: a 20-qubit quantum computer thats built for stability, but with some very flashy design.

IBM is touting the Q System One as the worlds first fully integrated universal quantum computing system designed for scientific and commercial use. But thats a description that needs a lot of context. The Q System One may be designed for commercial use, but its not exactly ready for it. Not in the way you might think.

Quantum computers like the Q System One are still very much experimental devices. They cant outperform classical computers at useful tasks (in fact, your laptop is probably more powerful when it comes to real-life computation), but are instead supposed to be research tools; letting us work out, qubit by qubit, how quantum devices might work at all.

Its more like a stepping stone than a practical quantum computer, Winfried Hensinger, professor of quantum technologies at the UKs University of Sussex, told The Verge. Dont think of this as a quantum computer that can solve all of the problems quantum computing is known for. Think of it as a prototype machine that allows you to test and further develop some of the programming that might be useful in the future.

And even as an experimental device, its not like IBM is going to start selling the Q System One at Best Buy. The company wont say how much it costs to buy one of these machines or even how many its made. Like IBMs other quantum computers, its accessible only via the cloud, where companies and research institutes can buy time on the IBM Q Network. And today IBM announced two new customers on the network: energy giant ExxonMobil, and European research lab CERN, the organization that built the Large Hadron Collider.

So whats special about the Q System One? Well, IBM says the main achievement is turning an experimental quantum machine into something with reliability (and looks) closer to that of a mainframe computer. Quantum computing is an extremely delicate business. Chips need to be kept at freezing temperatures and can be disturbed by the tiniest electrical fluctuations or physical vibrations. The Q System One, says IBM, minimizes these problems.

This is something IBM brings to the market that no one else really does. We know how to do integrated systems, IBMs VP of quantum research, Bob Sutor, tells The Verge. The electronics for a quantum computer are not something you go buy off the shelf. You need a temperature controlled environment, you need to minimize the vibrations anything that might disrupt the quantum calculations.

Sutor says that a practical advantage of engineering a machine like the Q System One is that it reduces research downtime. Resetting a quantum computer after an upset caused by a power surge or a disgruntled look from a technician is much, much quicker with a device like the Q System One. What used to take days and weeks now takes hour or days, says Sutor.

And while these might sound like marginal gains, if were ever going to have quantum computers that do change the world in all the ways we dream of (by discovering new drugs, for example, and unlocking fusion energy) reliable research will absolutely be key.

And perhaps just as importantly, the Q System One looks the part. The machine was designed by Map Project Office, an industrial design consultancy thats worked with companies like Sonos, Honda, and Graphcore. The Q System One is contained in a nine-foot borosilicate glass cube, with its delicate internals sheathed by a shiny, rounded black case. Its reminiscent of both Apples dustbin-like 2013 Mac Pro and the Monolith from 2001: A Space Odyssey. It looks like a computer from the future.

For IBM this is not simply a side benefit its part of the plan. The 107-year-old company may still rake in billions in revenue each quarter (mostly from legacy enterprise deals), but its facing what some analysts have called irreversible structural decline. Its failed to come out ahead in the tech industrys most recent growth areas, mobile and cloud computing, and it needs new revenue streams to carry it through its second century of existence. AI is one bet, quantum computing another.

Sutor doesnt mention these problems, but he does note that the Q System One is supposed to inspire confidence both in quantum computing and in IBM itself.

People, when they see quantum computing systems, their eyes just glow, he tells The Verge. And its because they understand that these things that were just rumored about, or that were just too futuristic, are now starting to be produced. They can look at these things and say, Ah, IBM sees the path forward!

And machines like the Q System One are still useful on these terms, giving people a glimpse of the future. But we need to remember, says Hensinger, that theres lots of work yet to be done. I wouldnt call this a breakthrough, he says. But its a productive step towards commercial realization of quantum computing.

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IBMs new quantum computer is a symbol, not a breakthrough

## IBM unveils the world’s first quantum computer that …

For many years, quantum computers have been within only the confines of the research lab.

On Tuesday, though, IBM unveiled the IBM Q System One, billed as the first-ever quantum computer designed for businesses to put to their own use though the company is clear that this is only the first step toward a broader revolution.

Quantum computing is considered one of the most promising early-stage technologies out there today. That’s because quantum computers can process exponentially more data and have the potential to completely transform entire industries. For example, they could streamline aerospace and military systems, calculate risk factors to make better investments, or, perhaps, find a cure for cancer and other diseases.

“Data will be the world’s most valuable natural resource,” IBM CEO Ginni Rometty said on stage at the Consumer Electronics Show in Las Vegas, where the IBM Q System One was unveiled.

Don’t expect to install one in your office any time soon, though. While the computer is open to paying customers, developers will access its power from the comfort of their own homes or offices via the IBM Cloud. IBM Q System One. IBM

Average computers store data in binary, as either zeroes or ones strings of ones and zeroes represent numbers or letters. However, quantum computers are much more powerful. That’s because they store data using “qubits,” which have a special property that allows zeroes and ones to exist simultaneously. This seemingly small thing gives quantum computers the ability to do exponentially more calculations at once, making them powerful enough for incredibly complicated tasks like drug discovery, intensive data analysis, and even creating unbreakable codes.

Enclosed in a 9-foot-tall, 9-foot-wide glass case that forms an air-tight environment, this sleek computer is IBM’s first effort to bring quantum computing to businesses. The casing is important: Qubits lose their quantum-computing properties outside of very specific conditions. A quantum computer has to be kept well below freezing in an environment that is mostly free of vibration and electromagnetic radiation.

IBM’s new system aims to address this challenge with an integrated quantum computer that solves all of that on behalf of its customers hence the casing, which keeps everything in shipshape. However, this relative fragility is why you won’t be installing an IBM Q System One in your own office while it’s definitely a major step forward, it’s far away from being something you can order and have delivered.

“The IBM Q System One is a major step forward in the commercialization of quantum computing,” Arvind Krishna, IBM’s senior vice president of hybrid cloud and director of research, said in a statement. “This new system is critical in expanding quantum computing beyond the walls of the research lab as we work to develop practical quantum applications for business and science.”

Read more: Here’s why we should be really excited about quantum computers

Later this year, IBM will also open its first IBM Q Quantum Computation Center for commercial customers in Poughkeepsie, New York. At this lab, clients can use IBM’s cloud-based quantum computing systems, as well as other high-performance computing systems.

IBM isn’t the only company that’s been working on quantum computing, as the technology is still far from ready for mass deployment.

Google is researching how to make quantum computers more stable and better able to find and fix errors, and it has also created and tested qubit processors as it pursues the technology. Microsoft is working on creating hybrid quantum computers, which combine the new technology with more conventional processors. Intel, too, has been working on quantum computing chips.

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IBM unveils the world’s first quantum computer that …

## Were Close to a Universal Quantum Computer, Heres Where We’re At

Quantum computers are just on the horizon as both tech giants and startups are working to kickstart the next computing revolution.

U.S. Nuclear Missiles Are Still Controlled By Floppy Disks – https://youtu.be/Y8OOp5_G-R4

Read More:Quantum Computing and the New Space Racehttp://nationalinterest.org/feature/q…In January 2017, Chinese scientists officially began experiments using the worlds first quantum-enabled satellite, which will carry out a series of tests aimed at investigating space-based quantum communications over the course of the next two years.

Quantum Leap in Computer Simulationhttps://pursuit.unimelb.edu.au/articl…Ultimately it will help us understand and test the sorts of problems an eventually scaled-up quantum computer will be used for, as the quantum hardware is developed over the next decade or so.

How Quantum Computing Will Change Your Lifehttps://www.seeker.com/quantum-comput… The Perimeter Institute of Theoretical Physics kicked off a new season of live-streamed public lectures featuring quantum information expert Michele Mosca.

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Were Close to a Universal Quantum Computer, Heres Where We’re At

## Schrdinger’s Killer App: Race to Build the World’s First …

“This is a beautifully written book that presents the carefully researched facts in an engaging style. The historical narrative, everywhere, is spiced up with entertaining anecdotes and sprinkled with references. The math and physics are presented through simple examples illustrated by drawing on analogies, while avoiding the use of any equations.”Contemporary Physics, 2014

” explains the difficult concepts of quantum mechanics to laypersons, using analogies that require no background in physics or advanced mathematics. These concepts include quantum entanglement, Schrodinger’s cat, and quantum computational complexity. Dowling (Louisiana State) has worked with the US Department of Defense (DoD) in their development of quantum information sciences for the last 20 years. The book’s title refers to the fact that all the encrypted communication of the Internet could easily be unveiled by a quantum computer, thus leading to competition to develop such a machine. The work begins with a discussion of Einstein, who fought against many notions of quantum physics, such as quantum entanglement and quantum computational complexity. The second chapter explains Bell’s theorem, proving that the entanglement ‘action at a distance’ idea actually takes place. Later chapters address how the public-key encryption system used by the Internet can be broken by a quantum computer; one-time pad encryption together with the unbreakable quantum key distribution technique and the DoD’s efforts to build a quantum computer; and the idea of building a quantum computer using entangled particles as the underlying building blocks. Recommended.” C. Tappert, Pace University, CHOICE Magazine

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Schrdinger’s Killer App: Race to Build the World’s First …

## How Quantum Computers Work

A quantum computer is a computer design which uses the principles of quantum physics to increase the computational power beyond what is attainable by a traditional computer. Quantum computers have been built on the small scale and work continues to upgrade them to more practical models.

Computers function by storing data in a binary number format, which result in a series of 1s & 0s retained in electronic components such as transistors.

Each component of computer memory is called a bit and can be manipulated through the steps of Boolean logic so that the bits change, based upon the algorithms applied by the computer program, between the 1 and 0 modes (sometimes referred to as “on” and “off”).

A quantum computer, on the other hand, would store information as either a 1, 0, or a quantum superposition of the two states. Such a “quantum bit” allows for far greater flexibility than the binary system.

Specifically, a quantum computer would be able to perform calculations on a far greater order of magnitude than traditional computers … a concept which has serious concerns and applications in the realm of cryptography & encryption. Some fear that a successful & practical quantum computer would devastate the world’s financial system by ripping through their computer security encryptions, which are based on factoring large numbers that literally cannot be cracked by traditional computers within the lifespan of the universe.

A quantum computer, on the other hand, could factor the numbers in a reasonable period of time.

To understand how this speeds things up, consider this example. If the qubit is in a superposition of the 1 state and the 0 state, and it performed a calculation with another qubit in the same superposition, then one calculation actually obtains 4 results: a 1/1 result, a 1/0 result, a 0/1 result, and a 0/0 result.

This is a result of the mathematics applied to a quantum system when in a state of decoherence, which lasts while it is in a superposition of states until it collapses down into one state. The ability of a quantum computer to perform multiple computations simultaneously (or in parallel, in computer terms) is called quantum parallelism).

The exact physical mechanism at work within the quantum computer is somewhat theoretically complex and intuitively disturbing. Generally, it is explained in terms of the multi-world interpretation of quantum physics, wherein the computer performs calculations not only in our universe but also in other universes simultaneously, while the various qubits are in a state of quantum decoherence. (While this sounds far-fetched, the multi-world interpretation has been shown to make predictions which match experimental results. Other physicists have )

Quantum computing tends to trace its roots back to a 1959 speech by Richard P. Feynman in which he spoke about the effects of miniaturization, including the idea of exploiting quantum effects to create more powerful computers. (This speech is also generally considered the starting point of nanotechnology.)

Of course, before the quantum effects of computing could be realized, scientists and engineers had to more fully develop the technology of traditional computers. This is why, for many years, there was little direct progress, nor even interest, in the idea of making Feynman’s suggestions into reality.

In 1985, the idea of “quantum logic gates” was put forth by University of Oxford’s David Deutsch, as a means of harnessing the quantum realm inside a computer. In fact, Deutsch’s paper on the subject showed that any physical process could be modeled by a quantum computer.

Nearly a decade later, in 1994, AT&T’s Peter Shor devised an algorithm that could use only 6 qubits to perform some basic factorizations … more cubits the more complex the numbers requiring factorization became, of course.

A handful of quantum computers has been built.

The first, a 2-qubit quantum computer in 1998, could perform trivial calculations before losing decoherence after a few nanoseconds. In 2000, teams successfully built both a 4-qubit and a 7-qubit quantum computer. Research on the subject is still very active, although some physicists and engineers express concerns over the difficulties involved in upscaling these experiments to full-scale computing systems. Still, the success of these initial steps does show that the fundamental theory is sound.

The quantum computer’s main drawback is the same as its strength: quantum decoherence. The qubit calculations are performed while the quantum wave function is in a state of superposition between states, which is what allows it to perform the calculations using both 1 & 0 states simultaneously.

However, when a measurement of any type is made to a quantum system, decoherence breaks down and the wave function collapses into a single state. Therefore, the computer has to somehow continue making these calculations without having any measurements made until the proper time, when it can then drop out of the quantum state, have a measurement taken to read its result, which then gets passed on to the rest of the system.

The physical requirements of manipulating a system on this scale are considerable, touching on the realms of superconductors, nanotechnology, and quantum electronics, as well as others. Each of these is itself a sophisticated field which is still being fully developed, so trying to merge them all together into a functional quantum computer is a task which I don’t particularly envy anyone …

except for the person who finally succeeds.

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How Quantum Computers Work

## This is what a 50-qubit quantum computer looks like

That’s where the pumps would normally come in. From top to bottom, the system gradually cools from four Kelvin — liquid-helium temperatures — to 800 milliKelvin, 100 milliKelvin and, finally, 10 milliKelvin. Inside the canister, that’s 10 thousandths of a degree above absolute zero. The wires, meanwhile, carry RF-frequency signals down to the chip. These are then mapped onto the qubits, executing whatever program the research team wishes to run. The wiring is also designed in a way to ensure that no extraneous noise — including heat — is transported to the quantum computer chip at the bottom.

Many in the industry have suggested that a 50-qubit system could achieve “quantum supremacy.” The term refers to the moment when a quantum computer is able to outperform a traditional system or accomplish a task otherwise thought impossible. The problem, though, is that quantum computers are only compatible with certain algorithms. They’re well-suited to quantum chemistry, for instance, and material simulations. But it’s unlikely you’ll ever use a quantum computer to complete a PowerPoint presentation. “The world is not classical, it’s quantum, so if you want to simulate it you need a quantum computer,” Welser said.

Researchers have already conducted experiments with quantum computers. Scientists at IBM were able to simulate beryllium hydride (BeH2) on a seven-qubit quantum processor last September, for example. But critics want to see a quantum computer accomplish something more tangible, which is more meaningful for the everyday consumer. That day, unfortunately, could still be a long way off.

“Somewhere between 50 and 100 qubits, we’ll reach the point where we can at least say very clearly, ‘I’ve just simulated a molecule here in a few minutes time that would have taken this giant system five days to do.’ That level we’ll be at fairly rapidly. When it gets to something that the public will understand in terms of an application they would use themselves, I can’t really speculate at this point,” Welser said.

Click here to catch up on the latest news from CES 2018.

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This is what a 50-qubit quantum computer looks like

## Inside Microsofts quantum computing world | InfoWorld

Quantum computers are the future, says Microsoft CEO Satya Nadella. And he has put Microsofts money where his mouth is, making quantum computing one of the three pillars of Microsofts strategy going forward. Along with AI and mixed/augmented reality, its an area where Nadella believes that Microsoft can make a significant impact, and where it can differentiate itself from its competition.

But building a quantum computer is hard. Microsofts current progress is the result of more than 20 years of research investment, working with universities around the world, mixing pure physics with computer science, and turning experimental ideas into products. Theres a lot of ambition here, with the eventual aim of building scalable quantum computers that anyone can use.

Microsofts approach to quantum computing differs from the technologies used by companies like DWave, taking a new approach to creating the qubits, the quantum bits at the heart of the process. Working with university researchers, Microsoft has been exploring use of a new type of particle, the Majorana fermion. Initially proposed in the late 1930s, Marjorana particles have only recently been detected in semiconductor nanowires at very low temperatures.

Compared to other qubit approaches, the Majorana particles used by Microsofts quantum computers are more stable and have lower error rates, spreading out the electron state across a topological knot thats less likely to evaporate when its state is read. This topological approach to quantum computing is something that Nadella calls a transistor moment for quantum computers. It might not be the quantum processor, but its the first step on that road.

Working with a quantum computer is very different from the machines we use today. A bits 1s and 0s are replaced by a qubit with a statistical blur of fractionalized electrons that needs interpretation. With qubits temperatures at near absolute zero, another specialised low-temperature (cryogenic) computer is used to program the qubits and read results, working with quantum algorithms to solve complex problemsand promising nearly instantaneous answers to problems that could take thousands, or even millions, of years with a modern supercomputer.

You can think of the relationship between the cryogenic controller and programs running on the ultralow-temperature quantum computer as something akin to how deep-sea divers work on underwater oil rigs. The quantum computer is the well head, isolated from the rest of the world by temperature. That makes the cryogenic control computer the equivalent of a divers pressurized diving bell, giving the programs a stepping stone between the normal temperatures of the outside world and the extreme cold of the quantum refrigerator, much like how a diving bell prepares divers for working at extreme depths.

Microsofts quantum computers are unlikely to run in your own datacenters. They require specialized refrigerators to chill the qubits, which are built from carefully grown nanowires. Microsofts consortium of universities can manufacture each part separately, bringing them together to deliver the current generation of test systems.

Microsoft intends to embed its quantum hardware in Azure, running a quantum simulator to help test quantum code before its deployed to actual quantum computers. Microsoft is also working on a new language to help developers write quantum code in Visual Studio.

Microsoft Research has already delivered a first cut at a quantum programming environment in Liqui|> (usually referred to as Liquid), a set of tools to simulate a 30-qubit environment on a PC with 32GB of memory. Microsoft says youll be able to deploy large quantum simulators with more than 40 qubits in 16TB on Azure, though solving problems of that size will take a long time without the acceleration of a real quantum computer.

Still, with Liquid, you can experiment with key quantum computing concepts using F#, seeing how youll build algorithms to handle complex mathematical concepts, as well as understanding how to work with low-level error-correction algorithms.

Microsofts new quantum computing language will build on lessons learned with Liquid, but it wont be based on F#. The languages name hasnt been revealed yet, but amusingly some early screenshots of quantum code being edited in Visual Studio appeared to use the same file extension as the classic Quick Basic.

I recently spoke with Krysta Svore, the lead of Microsoft Research s Redmond Quantum computing group, which works on building the software side of Microsofts planned scalable quantum computer. Its a fascinating side of the project, taking the low-level quantum algorithms needed to work with experimental hardware and finding ways of generating them from familiar high-level languages. If Svores team is successful, you wont need to know about the quantum computer youre programming; instead, youll write code, publish it to Azure, and run it.

The goal is that youll be able to concentrate on your code, not think about the underlying quantum circuitry. For example, instead of building the connections needed to construct a quantum Fourier transform, youll call a QFT library, writing additional code to prepare, load, and read data. As Svore notes, many quantum algorithms are hybrids, mixing preprocessing and postprocessing with quantum actions, often using them as part of loops run in a classical supercomputer.

Theres also a role for AI techniques, using machine learning to identify elements of code, understanding where and how they work best.

Developers who experiment with Liquid will be able to bring their applications to the new platform, with migration tools to help with the transition. Using the Azure-based quantum simulator should help, because it supports many more qubits than a PC does. Itll also let you explore working with execution-based parallelism, where you run multiple passes over the same data, rather than the more familiar GPGPU data parallelism model.

You can get a feel for what this means for computing when you consider an 80-qubit operation. Svore notes that a single operation in a quantum computer takes 100ns, no matter how many qubits you have. The same operation in a classical computer would require more particles than in the visible universe, taking longer than the lifetime of the universe. Solving that type of problem in 100ns is a huge leap forward, one that opens new directions for scientific computing.

Microsofts quantum computing work is a big bet on the future of computing. Today, its a long way from every day use, still in the domain of pure research, even if that research is coming up with promising results.

Where Microsofts quantum-computing work really will make a difference is if it can deliver a programming environment that will let us take hard problems and turn them into quantum algorithms quickly and repeatedly, without having to go beyond the familiar world of IDEs and parallel programming constructs. Getting that right will really change the world, in ways we cant yet imagine.

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Inside Microsofts quantum computing world | InfoWorld

## Microsoft Takes Path Less Traveled to Build a Quantum …

In the race to commercialize a new type of powerful computer, Microsoft Corp. has just pulled up to the starting line with a slick-looking set of wheels. Theres just one problem: it doesn’t have an engine at least not yet.

The Redmond, Washington-based tech giant is competing with Alphabet Inc.s Google, International Business Machines Corp. and a clutch of small, specialized companies to develop quantum computers machines that, in theory, will be many times more powerful than existing computers by bending the laws of physics.

Microsoft says it has a different approach that will make its technology less error-prone and more suitable for commercial use. If it works. On Monday, the company unveiled a new programming language called Q# pronounced Q Sharp and tools that help coders craft software for quantum computers. Microsoft is also releasing simulators that will let programmers test that software on a traditional desktop computer or through its Azure cloud-computing service.

The machines are one of the advanced technologies, along with artificial intelligence and augmented reality, that Microsoft Chief Executive Officer Satya Nadella considers crucial to the future of his company. Microsoft, like IBM and Google, will most likely rent computing time on these quantum machines through the internet as a service.

D-Wave Systems Inc. in 2011 became the first company to sell a quantum computer, although its technology has been controversial and can only perform a certain subset of mathematical problems. Google and IBM have produced machines that are thought to be close to achieving quantum supremacy the ability to tackle a problem too complex to solve on any standard supercomputer. IBM and startup Rigetti Computing also have software for their machines.

Microsoft, in contrast, is still trying to build a working machine. It is pursuing a novel design based on controlling an elusive particle called a Majorana fermion that no one was sure even existed a few years ago. Engineers are close to being able to control the Majorana fermionin a way that will enable them to perform calculations, Todd Holmdahl, head of Microsofts quantum computing efforts, said in an interview. Holmdahl, who led development of the Xbox and the company’s HoloLens goggles, said Microsoft will have a quantum computer on the market within five years.

We are talking to multiple customers today and we are proposing quantum-inspired services for certain problems, he added.

These systems push the boundaries of how atoms and other tiny particles work. While traditional computers process bits of information as 1s or zeros, quantum machines rely on “qubits” that can be a 1 and a zero at the same time. So two qubits can represent four numbers simultaneously, and three qubits can represent eight numbers, and so on. This means quantum computers can perform calculations much faster than standard machines and tackle problems that are way more complex.

Krysta Svore

Source: Microsoft

Applications could include things like creating new drugs and new materials or solving complex chemistry problems. The killer app of quantum computing is discovering a more efficient way to synthesize ammonia for fertilizer a process that currently consumes three percent of the worlds natural gas, according to Krysta Svore, who oversees the software aspects of Microsofts quantum work.

The technology is still emerging from a long research phase, and its capabilities are hotly debated. Researchers have only been able to keep qubits in a quantum state for fractions of a second. When qubits fall out of a quantum state they produce errors in their calculations, which can negate any benefit of using a quantum computer.

Microsoft says it uses a different design called a topological quantum computer that in theory will create more stable qubits. This couldproduce a machine with an error rate from 1,000 to10,000 times better than computers other companies are building, Holmdahl said.

Reducing or correcting the errors in quantum calculations is essential for the technology to fulfill its commercial potential, said Jonathan Breeze, a research fellow working on advanced materials at Imperial College London.

The lower error rate of Microsoft’s design may mean it can be more useful for tackling real applications — even with a smaller number of qubits perhaps less than 100. Svore said her team has already proven mathematically that algorithms that use a quantum approach can speed up machine learning applications substantially enabling them to run as much as 4,000 times faster. (Machine learning is a type of artificial intelligence behind recent advances in computers ability to identify objects in images, translate languages and drive cars).

“We want to solve today’s unsolvable problems and we have an opportunity with a unique, differentiated technology to do that,” Holmdahl said.

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## Researchers create new type of quantum computer | Harvard Gazette

Programming a computer is generally a fairly arduous process, involving hours of coding, not to mention the laborious work of debugging, testing, and documenting to make sure it works properly.

But for a team of physicists from the Harvard-MIT Center for Ultracold Atoms and the California Institute of Technology, things are actually much tougher.

Working in a Harvard Physics Department lab, a team of researchers led by Harvard Professors Mikhail Lukin and Markus Greiner and Massachusetts Institute of Technology Professor Vladan Vuletic developed a special type of quantum computer, known as a quantum simulator, that is programmed by capturing super-cooled rubidium atoms with lasers and arranging them in a specific order, then allowing quantum mechanics to do the necessary calculations.

The system could be used to shed light on a host of complex quantum processes, including the connection between quantum mechanics and material properties, and it could investigate new phases of matter and solve complex real-world optimization problems. The system is described in a Nov. 30 paper published in the journal Nature.

The combination of the systems large size and high degree of quantum coherence make it an important achievement, researchers say. With more than 50 coherent qubits, this is one of the largest quantum systems ever created with individual assembly and measurement.

In the same issue of Nature, a team from the Joint Quantum Institute at the University of Maryland described a similarly sized system of cold charged ions, also controlled with lasers. Taken together, these complimentary advances constitute a major step toward large-scale quantum machines.

Everything happens in a small vacuum chamber where we have a very dilute vapor of atoms which are cooled close to absolute zero, Lukin said. When we focus about 100 laser beams through this cloud, each of them acts like a trap. The beams are so tightly focused, they can either grab one atom or zero; they cant grab two. And thats when the fun starts.

Using a microscope, researchers can take images of the captured atoms in real time, and then arrange them in arbitrary patterns for input.

We assemble them in a way thats very controlled, said Ahmed Omran, a postdoctoral fellow in Lukins lab and a co-author of the paper. Starting with a random pattern, we decide which trap needs to go where to arrange them into desired clusters.

As researchers begin feeding energy into the system, the atoms begin to interact with each other. Those interactions, Lukin said, give the system its quantum nature.

We make the atoms interact, and thats really whats performing the computation, Omran said. In essence, as we excite the system with laser light, it self-organizes. Its not that we say this atom has to be a one or a zero we could do that easily just by throwing light on the atoms but what we do is allow the atoms to perform the computation for us, and then we measure the results.

Those results, Lukin and colleagues said, could shed light on complex quantum mechanical phenomena that are all but impossible to model using conventional computers.

If you have an abstract model where a certain number of particles are interacting with each other in a certain way, the question is why dont we just sit down at a computer and simulate it that way? asked Ph.D. student Alexander Keesling, another co-author. The reason is because these interactions are quantum mechanical in nature. If you try to simulate these systems on a computer, youre restricted to very small system sizes, and the number of parameters are limited.

If you make systems larger and larger, very quickly you will run out of memory and computing power to simulate it on a classical computer, he added. The way around that is to actually build the problem with particles that follow the same rules as the system youre simulating. Thats why we call this a quantum simulator.

Though its possible to use classical computers to model small quantum systems, the simulator developed by Lukin and colleagues uses 51 qubits, making it virtually impossible to replicate using conventional computing techniques.

It is important that we can start by simulating small systems using our machine, he said. So we are able to show those results are correct until we get to the larger systems, because there is no simple comparison we can make.

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When we start off, all the atoms are in a classical state. And when we read out at the end, we obtain a string of classical bits, zeros, and ones, said Hannes Bernien, another postdoctoral fellow in Lukins lab, and also a co-author. But in order to get from the start to the end, they have to go through the complex quantum mechanical state. If you have a substantial error rate, the quantum mechanical state will collapse.

Its that coherent quantum state, Bernien said, that allows the system to work as a simulator, and also makes the machine a potentially valuable tool for gaining insight into complex quantum phenomena and eventually performing useful calculations. The system already allows researchers to obtain unique insights into transformations between different types of quantum phases, called quantum phase transitions. It may also help shed light on new and exotic forms of matter, Lukin said.

Normally, when you talk about phases of matter, you talk about matter being in equilibrium, he said. But some very interesting new states of matter may occur far away from equilibrium and there are many possibilities for that in the quantum domain. This is a completely new frontier.

Already, Lukin said, the researchers have seen evidence of such states. In one of the first experiments conducted with the new system, the team discovered a coherent non-equilibrium state that remained stable for a surprisingly long time.

Quantum computers will be used to realize and study such non-equilibrium states of matter in the coming years, he said. Another intriguing direction involves solving complex optimization problems. It turns out one can encode some very complicated problems by programming atom locations and interactions between them. In such systems, some proposed quantum algorithms could potentially outperform classical machines. Its not yet clear whether they will or not, because we just cant test them classically. But we are on the verge of entering the regime where we can test them on the fully quantum machines containing over 100 controlled qubits. Scientifically, this is really exciting.

Other co-authors of the study were visiting scientist Sylvain Schwartz, Harvard graduate students Harry Levine and Soonwon Choi, research associate Alexander S. Zibrov, and Professor Manuel Endres.

This research was supported with funding from the National Science Foundation, the Center for Ultracold Atoms, the Army Research Office, and the Vannevar Bush Faculty Fellowship.

By Arthur Goldhammer, Center for European Studies | November 30, 2017

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Researchers create new type of quantum computer | Harvard Gazette

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