Category: Quantum


An international team of scientists has come up with a blueprint for a large-scale quantum computer

By Hugo Angel,

‘It is the Holy Grail of science … we will be able to do certain things we could never even dream of before’
Courtesy Professor Winfried Hensinger
Quantum computing breakthrough could help ‘change life completely‘, say scientists
Scientists claim to have produced the first-ever blueprint for a large-scale quantum computer in a development that could bring about a technological revolution on a par with the invention of computing itself.
Until now quantum computers have had just a fraction of the processing power they are theoretically capable of producing.
But an international team of researchers believe they have finally overcome the main technical problems that have prevented the construction of more powerful machines.
They are currently building a prototype and a full-scale quantum computer – many millions of times faster than the best currently available – could be built in about a decade.
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Such devices work by utilising the almost magical properties found in the world of the very small, where an atom can apparently exist in two different places at the same time.
Professor Winfried Hensinger, head of the Ion Quantum Technology Group at Sussex University, who has been leading this research, told The Independent: “It is the Holy Grail of science, really, to build a quantum computer.
And we are now publishing the actual nuts-and-bolts construction plan for a large-scale quantum computer.
It is thought the astonishing processing power unleashed by quantum mechanics will lead to new, life-saving medicines, help solve the most intractable scientific problems, and probe the mysteries of the universe.
Life will change completely. We will be able to do certain things we could never even dream of before,” Professor Hensinger said.
You can imagine that suddenly the sky is the limit.
This is really, really exciting … it’s probably one of the most exciting times to be in this field.
He said small quantum computers had been built in the past but to test the theories.
This is not an academic study any more, it really is all the engineering required to build such a device,” he said.
Nobody has really gone ahead and drafted a full engineering plan of how you build one.
Many people questioned, because this is so hard to make this happen, that it can even be built.
We show that not only can it be built, but we provide a whole detailed plan on how to make it happen.
The problem is that existing quantum computers require lasers focused precisely on individual atoms. The larger the computer, the more lasers are required and the greater the chance of something going wrong.
But Professor Hensinger and colleagues used a different technique to monitor the atoms involving a microwave field and electricity in an ‘ion-trap’ device.

What we have is a solution that we can scale to arbitrary [computing] power,” he said.

Fig. 2. Gradient wires placed underneath each gate zone and embedded silicon photodetector.
(A) Illustration showing an isometric view of the two main gradient wires placed underneath each gate zone. Short wires are placed locally underneath each gate zone to form coils, which compensate for slowly varying magnetic fields and allow for individual addressing. The wire configuration in each zone can be seen in more detail in the inset.
(B) Silicon photodetector (marked green) embedded in the silicon substrate, transparent center segmented electrodes, and the possible detection angle are shown. VIA structures are used to prevent optical cross-talk from neighboring readout zones.
Source: Science Journals — AAAS. Blueprint for a microwave trapped ion quantum computer. Lekitsch et al. Sci. Adv. 2017;3: e1601540 1 February 2017
Fig. 4. Scalable module illustration. One module consisting of 36 × 36 junctions placed on the supporting steel frame structure: Nine wafers containing the required DACs and control electronics are placed between the wafer holding 36 × 36 junctions and the microchannel cooler (red layer) providing the cooling. X-Y-Z piezo actuators are placed in the four corners on top of the steel frame, allowing for accurate alignment of the module. Flexible electric wires supply voltages, currents, and control signals to the DACs and control electronics, such as field-programmable gate arrays (FPGAs). Coolant is supplied to the microchannel cooler layer via two flexible steel tubes placed in the center of the modules.
Source: Science Journals — AAAS. Blueprint for a microwave trapped ion quantum computer. Lekitsch et al. Sci. Adv. 2017;3: e1601540 1 February 2017
Fig. 5. Illustration of vacuum chambers. Schematic of octagonal UHV chambers connected together; each chamber is 4.5 × 4.5 m2 large and can hold >2.2 million individual X-junctions placed on steel frames.
Source: Science Journals — AAAS. Blueprint for a microwave trapped ion quantum computer. Lekitsch et al. Sci. Adv. 2017;3: e1601540 1 February 2017

We are already building it now. Within two years we think we will have completed a prototype which incorporates all the technology we state in this blueprint.

At the same time we are now looking for industry partner so we can really build a large-scale device that fills a building basically.
It’s extraordinarily expensive so we need industry partners … this will be in the 10s of millions, up to £100m.
Commenting on the research, described in a paper in the journal Science Advances, other academics praised the quality of the work but expressed caution about how quickly it could be developed.
Dr Toby Cubitt, a Royal Society research fellow in quantum information theory at University College London, said: “Many different technologies are competing to build the first large-scale quantum computer. Ion traps were one of the earliest realistic proposals. 
This work is an important step towards scaling up ion-trap quantum computing.
Though there’s still a long way to go before you’ll be making spreadsheets on your quantum computer.
And Professor Alan Woodward, of Surrey University, hailed the “tremendous step in the right direction”.
It is great work,” he said. “They have made some significant strides forward.

But he added it was “too soon to say” whether it would lead to the hoped-for technological revolution.

ORIGINAL: The Independent
Ian Johnston Science Correspondent
Thursday 2 February 2017

Quantum Computers Explained – Limits of Human Technology

By Hugo Angel,

Where are the limits of human technology? And can we somehow avoid them? This is where quantum computers become very interesting. 
Check out THE NOVA PROJECT to learn more about dark energy: www.nova.org.au 


ORIGINAL: YouTube



  Category: Computing, Physics, Quantum
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Scientists have built a functional ‘hybrid’ logic gate for use in quantum computers

By Hugo Angel,

NIST Quantum Gate
An ion trap used in NIST quantum computing experiments. Credit: Blakestad/NIST
Here’s how to solve the problem of quantum memory.
As conventional computers draw ever closer to their theoretical limit, the race is on to build a machine that can truly harness the unprecedented processing power of quantum computing. And now two research teams have independently demonstrated how entangling atoms from different elements can address the problem of quantum memory errors while functioning within a logic gate framework, and also pass the all-important test of true entanglement. 
Hybrid quantum computers allow the unique advantages of different types of quantum systems to be exploited together in a single platform,said lead author Ting Rei Tan. “Each ion species is unique, and certain ones are better suited for certain tasks such as memory storage, while others are more suited to provide interconnects for data transfer between remote systems.
In the computers we use today, data is processed and stored as binary bits, with each individual bit taking on a state of either 0 or 1. Because these states are set, there’s a finite amount of information that can ultimately be processed, and we’re quickly approaching the point where this isn’t going to be enough.
Quantum computers, on the other hand, store data as qubits, which can be in the state of 0 or 1, or can take on another state called superposition, which allows them to be both 0 and 1 at the same time. If we can figure out how to build a machine that integrates this phenomenon with data-processing capabilities, we’re looking at computers that are hundreds of millions of times faster than the super computers of today.
The qubits used in this set-up are actually atomic ions (atoms with an electron removed), and their states are determined by their spin – spin up is 1, spin down is 0. Each atomic ion is paired off, and if the control ion takes on the state of superposition, it will become entangled with its partner, so anything you do to one ion will affect the other.
This can pose problems, particularly when it comes to memory, and there’s no point storing and processing information if you can’t reliably retain it. If you’ve got an entire system built on pairs of the same atomic ions, you leave yourself open to constant errors, because if one ion is affected by a malfunction, this will also affect its partner. At the same time, using the same atomic ions in a pair makes it very difficult for them to perform separate functions.
So researchers from the University of Oxford in the UK, and a second team from the National Institute of Standards and Technology (NIST) and the University of Washington, have figured out which combinations of different elements can function together as pairs in a quantum set-up.
Each trapped ion is used to represent one ‘quantum bit’ of information. The quantum states of the ions are controlled with laser pulses of precise frequency and duration,says one of the researchers, David Lucas from the University of Oxford. “Two different species of ion are needed in the computer

  • one to store information, a ‘memory qubit’, and 
  • one to link different parts of the computer together via photons, an ‘interface qubit’.
While the Oxford team achieved this using two different isotopes of calcium (the abundant isotope calcium-40 and the rare isotope calcium-43), the second team went even further by pairing up entirely different atoms – magnesium and beryllium. Each one is sensitive to a different wavelength of light, which means zapping one with a laser pulse to control its function won’t affect its partner.
The teams them went on to demonstrate for the first time that these pairs could have their 0,1, or superposition states controlled by two different types of logic gates, called the CNOT gate and the SWAP gate. Logic gates are crucial components of any digital circuit, because they’re able to record two input values and provide a new output based on programmed logic. 
A CNOT gate flips the second (target) qubit if the first (control) qubit is a 1; if it is a 0, the target bit is unchanged,the NIST press release explains. “If the control qubit is in a superposition, the ions become entangled. A SWAP gate interchanges the qubit states, including superpositions.
The Oxford team demonstrated ion pairing in this set-up for about 60 seconds, while the NIST/Washington team managed to keep theirs entangled for 1.5 seconds. That doesn’t sound like much, but that’s relatively stable when it comes to qubits.
Both teams confirm that their two atoms are entangled with a very high probability; 0.998 for one, 0.979 for the other (of a maximum of one),John Timmer reports for Ars Technica. “The NIST team even showed that it could track the beryllium atom as it changed state by observing the state of the magnesium atom.
Further, both teams were able to successfully perform a Bell test by using the logic gate to entangle the pairs of different-species ions, and then manipulating and measuring them independently.
[W]e show that quantum logic gates between different isotopic species are possible, can be driven by a relatively simple laser system, and can work with precision beyond the so-called ‘fault-tolerant threshold’ precision of approximately 99 percent – the precision necessary to implement the techniques of quantum error correction, without which a quantum computer of useful size cannot be built,said Lucas in an Oxford press release.
Of course, we don’t have proper quantum computers to actually test these components in the context of a functioning system – that will have to be the next step, and international teams of scientists and engineers are racing to get us there. We can’t wait to see it when they do.
The papers have been published in Nature here and here.
ORIGINAL: ScienceAlert
BEC CREW
18 DEC 2015

Google says its quantum computer is more than 100 million times faster than a regular computer chip

By Hugo Angel,

NASA Quantum Vesuvius Close Up
Above: The D-Wave 2X quantum computer at NASA Ames Research Lab in Mountain View, California, on December 8.
Image Credit: Jordan Novet/VentureBeat
Google appears to be more confident about the technical capabilities of its D-Wave 2X quantum computer, which it operates alongside NASA at the U.S. space agency’s Ames Research Center in Mountain View, California.
D-Wave’s machines are the closest thing we have today to quantum computing, which works with quantum bits, or qubits — each of which can be zero or one or both — instead of more conventional bits. The superposition of these qubits enable machines to make great numbers of computations to simultaneously, making a quantum computer highly desirable for certain types of processes.
In two tests, the Google NASA Quantum Artificial Intelligence Lab today announced that it has found the D-Wave machine to be considerably faster than simulated annealing — a simulation of quantum computation on a classical computer chip.
Google director of engineering Hartmut Neven went over the results of the tests in a blog post today:
We found that for problem instances involving nearly 1,000 binary variables, quantum annealing significantly outperforms its classical counterpart, simulated annealing. It is more than 108 times faster than simulated annealing running on a single core. We also compared the quantum hardware to another algorithm called Quantum Monte Carlo. This is a method designed to emulate the behavior of quantum systems, but it runs on conventional processors. While the scaling with size between these two methods is comparable, they are again separated by a large factor sometimes as high as 108.
Google has also published a paper on the findings.
If nothing else, this is a positive signal for venture-backed D-Wave, which has also sold quantum computers to Lockheed Martin and Los Alamos National Laboratory. At an event at NASA Ames today where reporters looked at the D-Wave machine, chief executive Vern Brownell sounded awfully pleased at the discovery. Without question, the number 100,000,000 is impressive. It’s certainly the kind of thing the startup can show when it attempts to woo IT buyers and show why its technology might well succeed in disrupting legacy chipmakers such as Intel.
But Google continues to work with NASA on quantum computing, and meanwhile Google also has its own quantum computing hardware lab. And in that initiative, Google is still in the early days.
I would say building a quantum computer is really, really hard, so first of all, we’re just trying to get it to work and not worry about cost or size or whatever,” said John Martinis, the person leading up Google’s hardware program and a professor of physics at the University of California, Santa Barbara.
Commercial applications of this technology might not happen overnight, but it’s possible that eventually they could lead to speed-ups for things like image recognition, which is in place inside of many Google services. But the tool could also come in handy for a traditional thing like cleaning up dirty data. Outside of Google, quantum speed-ups could translate into improvements for planning and scheduling and air traffic management, said David Bell, director of the Universities Space Research Association’s Research Institute for Advanced Computer Science, which also works on the D-Wave machine at NASA Ames.
ORIGINAL: Venture Beat
DECEMBER 8, 2015

Quantum boost for artificial intelligence

By admin,

Quantum computers able to learn could attack larger sets of data than classical computers.


Peter Arnold/Stegerphoto/Getty Images

 

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Programs running on future quantum computers could dramatically speed up complex tasks such as face recognition.
Quantum computers of the future will have the potential to give artificial intelligence a major boost, a series of studies suggests.
These computers, which encode information in ‘fuzzy’ quantum states that can be zero and one simultaneously, have the ability to someday solve problems, such as breaking encryption keys, that are beyond the reach of ‘classical’ computers.
Algorithms developed so far for quantum computers have typically focused on problems such as breaking encryption keys or searching a list — tasks that normally require speed but not a lot of intelligence. But in a series of papers posted online this month the arXiv preprint server1, 2, 3, Seth Lloyd of the Massachusetts Institute of Technology in Cambridge and his collaborators have put a quantum twist on AI.
The team developed a quantum version of ‘machine learning’, a type of AI in which programs can learn from previous experience to become progressively better at finding patterns in data. Machine learning is popular in applications ranging from e-mail spam filters to online-shopping suggestions. The team’s invention would take advantage of quantum computations to speed up machine-learning tasks exponentially.
Quantum leap
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At the heart of the scheme is a simpler algorithm that Lloyd and his colleagues developed in 2009 as a way of quickly solving systems of linear equations, each of which is a mathematical statement, such as x + y = 4. Conventional computers produce a solution through tedious number crunching, which becomes prohibitively difficult as the amount of data (and thus the number of equations) grows. A quantum computer can cheat by compressing the information and performing calculations on select features extracted from the data and mapped onto quantum bits, or qubits.
Quantum machine learning takes the results of algebraic manipulations and puts them to good use. Data can be split into groups — a task that is at the core of handwriting- and speech-recognition software — or can be searched for patterns. Massive amounts of information could therefore be manipulated with a relatively small number of qubits.
We could map the whole Universe — all of the information that has existed since the Big Bang — onto 300 qubits,” Lloyd says.
Such quantum AI techniques could dramatically speed up tasks such as image recognition for comparing photos on the web or for enabling cars to drive themselves — fields in which companies such as Google have invested considerable resources. (One of Lloyd’s collaborators, Masoud Mohseni, is in fact a Google researcher based in Venice, California.)
It’s really interesting to see that there are new ways to use quantum computers coming up, after focusing mostly on factoring and quantum searches,” says Stefanie Barz at the University of Vienna, who recently demonstrated quantum equation-solving in action. Her team used a simple quantum computer that had two qubits to work out a high-school-level maths problem: a system consisting of two equations4. Another group, led by Jian Pan at the University of Science and Technology of China in Hefei, did the same using four qubits5.
Putting quantum machine learning into practice will be more difficult. Lloyd estimates that a dozen qubits would be needed for a small-scale demonstration.

Nature doi:10.1038/nature.2013.13453

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ORIGINAL: Nature
26 July 2013

A first look inside Google’s futuristic quantum lab

By admin,

ORIGINAL: The Verge
By Russell Brandom
October 10, 2013

In May, Google launched the Quantum Artificial Intelligence Lab with hardware from the Canadian quantum computing company D-Wave and technical expertise from NASA. It was an ambitious open research project aimed at exploring both the capabilities of quantum computer architecture and the mysteries of space exploration — but in the months since, they’ve stayed quiet about exactly what kind of work they’ve been doing there.

Operated at near-absolute-zero temperatures

Tomorrow, they’re breaking the silence with a brief short film, set to debut at the Imagine Science Films Festival at Google New York. The film takes a look at various researchers working on the project, as well as the computer itself, which has to be operated at near-absolute-zero temperatures. Researchers hope the quantum architecture will eventually be used to optimize solutions across complex and interconnected sets of variables currently outside the capabilities of conventional computing. That could allow for new solutions in computational medicine or help NASA to construct a more comprehensive picture of the known universe. “We don’t know what the best questions are to ask that computer,” says NASA’s Eleanor Rieffel in the video. “That’s exactly what we’re trying to understand.”

Video provided by Google

We don’t know what the best questions are to ask that computer.

Beyond the film, Google says it’s made great leaps in recent experiments with the quantum chips, determining which algorithms work better in a quantum setup and providing further evidence that the D-Wave processor uses quantum entanglement, a behavior that links particles with no apparent physical connection between them. D-Wave has always claimed that its chips involved entanglement, but it had been difficult to conclusively demonstrate before now.

The first practical application has been on Google Glass, as engineers put the quantum chips to work on Glass’s blink detector, helping it to better distinguish between intentional winks and involuntary blinks. For engineering reasons, the quantum processor can never be installed in Glass, but together with Google’s conventional server centers, it can point the way to a better blink-detecting algorithm. That would allow the Glass processor to detect blinks with better accuracy and using significantly less power. If successful, it could be an important breakthrough for wink-triggered apps, which have struggled with the task so far.

A world first! Success at complete quantum teleportation

By admin,

ORIGINAL: DigInfo TV
The University of Tokyo
11/9/2013
Furusawa group at the University of Tokyo has succeeded in demonstrating complete quantum teleportation of photonic quantum bits by a hybrid technique for the first time worldwide. In 1997, quantum teleportation of photonic quantum bits was achieved by a research team at Innsbruck University in Austria. However, such quantum teleportation couldn’t be used for information processing, because measurement was reqI think we can definitely say that quantum computers have come closer to reality. Teleportation can be thought of as a quantum gate where input and output are the same. So, it’s known that, if we improve this a little, the input and output could be produced in different forms. If changing the form of input and output like that is considered as a program, you have a programmable quantum gate. So, I think a quantum computer could be achieved by combining lots of those.uired after transport, and the transport efficiency was low. So, quantum teleportation was still a long way from practical use in quantum communication and quantum computing. The demonstration of quantum teleportation of photonic quantum bits by Furusawa group shows that transport efficiency can be over 100 times higher than before. Also, because no measurement is needed after transport, this result constitutes a major advance toward quantum information processing technology.”In 1997, quantum bit teleportation was successfully achieved, but as I said just now, it was only achieved in a probabilistic sense. In 1998, we used a slightly different method to succeed at unconditional, complete teleportation. But at that time, the state sent wasn’t a quantum bit, but something different. Now, we’ve used our experimental technology, which was successful in 1998, to achieve teleportation with quantum bits. The title of our paper is “Hybrid Technique,” and developing that technique is where we’ve been successful.

The hybrid technique was developed by combining technology for transporting light waves with a broad frequency range, and technology for reducing the frequency range of photonic quantum bits. This has made it possible to incorporate photonic quantum bit information into light waves without disruption by noise. This research result has been published in Nature, and is attracting attention worldwide, as a step toward quantum information processing technology.

I think we can definitely say that quantum computers have come closer to reality. Teleportation can be thought of as a quantum gate where input and output are the same. So, it’s known that, if we improve this a little, the input and output could be produced in different forms. If changing the form of input and output like that is considered as a program, you have a programmable quantum gate. So, I think a quantum computer could be achieved by combining lots of those.

Looking ahead, Furusawa group aims to increase the transport efficiency and make the device smaller by using photonic chips. In this way, the researchers plan to achieve further advances toward quantum computing.

  Category: Computing, Quantum
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