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  • richardmitnick 3:22 pm on March 13, 2019 Permalink | Reply
    Tags: "Quantum computing should supercharge this machine-learning technique", , Certain machine-learning tasks could be revolutionized by more powerful quantum computers., , , Quantum computers   

    From M.I.T Technology Review: “Quantum computing should supercharge this machine-learning technique” 

    MIT Technology Review
    From M.I.T Technology Review

    March 13, 2019
    Will Knight

    1
    The machine-learning experiment was performed using this IBM Q quantum computer.

    Certain machine-learning tasks could be revolutionized by more powerful quantum computers.

    Quantum computing and artificial intelligence are both hyped ridiculously. But it seems a combination of the two may indeed combine to open up new possibilities.

    In a research paper published today in the journal Nature, researchers from IBM and MIT show how an IBM quantum computer can accelerate a specific type of machine-learning task called feature matching. The team says that future quantum computers should allow machine learning to hit new levels of complexity.

    As first imagined decades ago, quantum computers were seen as a different way to compute information. In principle, by exploiting the strange, probabilistic nature of physics at the quantum, or atomic, scale, these machines should be able to perform certain kinds of calculations at speeds far beyond those possible with any conventional computer (see “What is a quantum computer?”). There is a huge amount of excitement about their potential at the moment, as they are finally on the cusp of reaching a point where they will be practical.

    At the same time, because we don’t yet have large quantum computers, it isn’t entirely clear how they will outperform ordinary supercomputers—or, in other words, what they will actually do (see “Quantum computers are finally here. What will we do with them?”).

    Feature matching is a technique that converts data into a mathematical representation that lends itself to machine-learning analysis. The resulting machine learning depends on the efficiency and quality of this process. Using a quantum computer, it should be possible to perform this on a scale that was hitherto impossible.

    The MIT-IBM researchers performed their simple calculation using a two-qubit quantum computer. Because the machine is so small, it doesn’t prove that bigger quantum computers will have a fundamental advantage over conventional ones, but it suggests that would be the case, The largest quantum computers available today have around 50 qubits, although not all of them can be used for computation because of the need to correct for errors that creep in as a result of the fragile nature of these quantum bits.

    “We are still far off from achieving quantum advantage for machine learning,” the IBM researchers, led by Jay Gambetta, write in a blog post. “Yet the feature-mapping methods we’re advancing could soon be able to classify far more complex data sets than anything a classical computer could handle. What we’ve shown is a promising path forward.”

    “We’re at stage where we don’t have applications next month or next year, but we are in a very good position to explore the possibilities,” says Xiaodi Wu, an assistant professor at the University of Maryland’s Joint Center for Quantum Information and Computer Science. Wu says he expects practical applications to be discovered within a year or two.

    Quantum computing and AI are hot right now. Just a few weeks ago, Xanadu, a quantum computing startup based in Toronto, came up with an almost identical approach to that of the MIT-IBM researchers, which the company posted online. Maria Schuld, a machine-learning researcher at Xanadu, says the recent work may be the start of a flurry of research papers that combine the buzzwords “quantum” and “AI.”

    “There is a huge potential,” she says.

    See the full article here .


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  • richardmitnick 11:27 am on September 27, 2018 Permalink | Reply
    Tags: , Atom-based quantum computer, , , Quantum computers, , , Rubidium atoms, Rydberg state,   

    From Science Magazine: “Arrays of atoms emerge as dark horse candidate to power quantum computers” 

    AAAS
    From Science Magazine

    Sep. 26, 2018
    Sophia Chen

    1
    Lasers are used to trap arrays of atoms within glass chambers made by ColdQuanta, a neutral atom quantum computing startup.
    COLDQUANTA INC.

    In a small basement laboratory, Harry Levine, a Harvard University graduate student in physics, can assemble a rudimentary computer in a fraction of a second. There isn’t a processor chip in sight; his computer is powered by 51 rubidium atoms that reside in a glass cell the size of a matchbox. To create his computer, he lines up the atoms in single file, using a laser split into 51 beams. More lasers—six beams per atom—slow the atoms until they are nearly motionless. Then, with yet another set of lasers, he coaxes the atoms to interact with each other, and, in principle, perform calculations.

    It’s a quantum computer, which manipulates “qubits” that can encode zeroes and ones simultaneously in what’s called a superposition state. If scaled up, it might vastly outperform conventional computers at certain tasks. But in the world of quantum computing, Levine’s device is somewhat unusual. In the race to build a practical quantum device, investment has largely gone to qubits that can be built on silicon, such as tiny circuits of superconducting wire and small semiconductors structures known as quantum dots. Now, two recent studies have demonstrated the promise of the qubits Levine works with: neutral atoms. In one study, a group including Levine showed a quantum logic gate made of two neutral atoms could work with far fewer errors than ever before. And in another, researchers built 3D structures of carefully arranged atoms, showing that more qubits can be packed into a small space by taking advantage of the third dimension.

    The advances, along with the arrival of venture capital funding, suggest neutral atoms could be on the upswing, says Dana Anderson, CEO of ColdQuanta, a Boulder, Colorado–based company that is developing an atom-based quantum computer. “We’ve done our homework,” Anderson says. “This is really in the engineering arena now.”

    Because neutral atoms lack electric charge and interact reluctantly with other atoms, they would seem to make poor qubits. But by using specifically timed laser pulses, physicists can excite an atom’s outermost electron and move it away from the nucleus, inflating the atom to billions of times its usual size. Once in this so-called Rydberg state, the atom behaves more like an ion, interacting electromagnetically with neighboring atoms and preventing them from becoming Rydberg atoms themselves.

    Physicists can exploit that behavior to create entanglement—the quantum state of interdependence needed to perform a computation. If two adjacent atoms are excited into superposition, where both are partially in a Rydberg state and partially in their ground state, a measurement will collapse the atoms to one or the other state. But because only one of the atoms can be in its Rydberg state, the atoms are entangled, with the state of one depending on the state of the other.

    Once entangled, neutral atoms offer some inherent advantages. Atoms need no quality control: They are by definition identical. They’re much smaller than silicon-based qubits, which means, in theory, more qubits can be packed into a small space. The systems operate at room temperature, whereas superconducting qubits need to be placed inside a bulky freezer. And because neutral atoms don’t interact easily, they are more immune to outside noise and can hold onto quantum information for a relatively long time. “Neutral atoms have great potential,” says Mark Saffman, a physicist at the University of Wisconsin in Madison. “From a physics perspective, [they could offer] easier scalability and ultimately better performance.”

    Entangled atoms

    The two new studies bolster these claims. By engineering better quality lasers, Levine and his colleagues, led by physicist Mikhail Lukin at Harvard, were able to accurately program a two-rubidium atom logic gate 97% of the time, they report in a paper published on 20 September in Physical Review Letters. That puts the method closer to the performance of superconducting qubits, which already achieve fidelity rates above 99%. In a second study, published in Nature on 5 September, Antoine Browaeys of the Charles Fabry Laboratory near Paris and his colleagues demonstrated an unprecedented level of control over a 3D array of 72 atoms. To show off their control, they even arranged the atoms into the shape of the Eiffel Tower. Another popular qubit type, ions, are comparably small. But they can’t be stacked this densely because they repel each other, acknowledges Crystal Senko, a physicist at the University of Waterloo in Canada who works on ion quantum computers.

    Not everyone is convinced. Compared with other qubits, neutral atoms tend not to stay put, says Varun Vaidya, a physicist at Xanadu, a quantum computing company in Toronto, Canada, that builds quantum devices with photon qubits. “The biggest issue is just holding onto the atoms,” he says. If an atom falls out of place, Lukin’s automated laser system can reassemble the atoms in less than a second, but Vaidya says this may still prohibit the devices from performing longer tasks. “Right now, nobody knows what’s going to be the best qubit,” Senko says. “The bottom line is, they all have their problems.”

    Still, ColdQuanta has recently received $6.75 million in venture funding. Another startup, Atom Computing, based in Berkeley, California, has raised $5 million. CEO Ben Bloom says the company will pursue qubits made of atoms with two valence electrons instead of rubidium’s one, such as calcium and strontium. Bloom believes these atoms will allow for longer-lived qubits. Lukin says he’s also interested in commercializing his group’s technology.

    The startups, as well as Saffman’s group, are aiming to build fully programmable quantum computers. For now, Lukin wants his group to focus on building quantum simulators, a more limited kind of computer that specializes in solving specific optimization problems by preparing the qubits a certain way and letting them evolve naturally. Levine says his group’s device could, for example, help telecommunications engineers figure out where to put radio towers to minimize cost and maximize coverage. “We’re going to try to do something useful with these devices,” Levine says. “People still don’t know yet what quantum systems can do.”

    In the next year or two, he and his colleagues think neutral atom devices could deliver an answer.

    See the full article here .


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  • richardmitnick 11:39 am on August 10, 2018 Permalink | Reply
    Tags: Centre of Excellence for Quantum Computation and Communication Technology, Professor Michelle Simmons, Quantum computers, ,   

    From University of New South Wales: Women in STEM- “School students get exclusive insights into the world of quantum” Professor Michelle Simmons 

    U NSW bloc

    From University of New South Wales

    10 Aug 2018
    Isabelle Dubach

    Hundreds of school students got a rare peek into what life as a scientist could be like, as Professor Michelle Simmons opened the doors of the Centre of Excellence for Quantum Computation and Communication Technology ahead of National Science Week.

    1
    Professor Simmons, Eddie Woo and the Simmons class.

    When Scientia Professor Michelle Simmons became Australian of the Year 2018, her acceptance speech touched on themes that resonated with many school students and teachers: her encouragement of all young people to pursue what they love, to set their sights high, to tackle the hardest challenges in life and to be the creators – not just the users – of technology.

    Following the ceremony – and numerous subsequent speech invites from schools across Australia – Professor Simmons and her team decided to open the doors of the Centre for Quantum Computation and Communication Technology for one full day, to offer students the opportunity to see the team’s groundbreaking research in action – a first in the centre’s history.

    Professor Simmons said the goal was to open the students’ minds to the possibilities a career in STEM offers.

    “When I was younger, I got to see a fabrication plant in the US, and observed how they make semi-conductor chips. It completely opened my mind to the world of possibility that was out there. I remember thinking that all children should see this.

    “So here we are in Australia, we’ve got this great facility of building chips in-house, so I’m hoping we opened the students’ eyes to what’s out there, to all the kind of jobs they can have, and just get them excited by science.”

    A rare view into quantum labs

    The day was jam-packed, with primary school students visiting the centre in the morning, and secondary students following in the afternoon. After an official welcome and a mini-lecture by Michelle Simmons, the first school group was led through the quantum laboratories to witness the technology being used to build a quantum computer in silicon.

    The students were led through a range of different labs – each one dedicated to building and testing different components of the silicon quantum computer chip. This includes the Scanning Tunnelling Microscope “Atom” lab where the atoms are placed precisely onto a silicon chip, the Clean Rooms where miniature wires are added to the silicon chips, and the “Cryo” Fridge Lab, which tests the electrical response of the atom qubits in fridges at temperatures close to -273 degree C.

    2
    3
    4
    Students in the CQC2T labs.

    Enlightening workshops and experiments

    Students also embarked on a series of interactive workshops and presentations. Hands-on experiments included a ‘silicon full clean’ station, where students got an insight into the day-to-day of the centre’s researchers by helping clean silicon samples. In another experiment, research staff cooled down several everyday objects – like fruit and marshmallow – with liquid nitrogen, to show students how materials react to different temperatures. Students were fascinated to observe how the fruit, for example, becomes very brittle when exposed to nitrogen.

    5
    Students participating in experiments.

    6
    Students at the ‘silicon full clean’ station.

    Special guest and star maths teacher Eddie Woo showed the students a mind-blowing card trick to illustrate fundamental principles of maths.

    “By showing the kids some practical mathematics with something as simple as a deck of cards, I’m hoping to have demonstrated to them that there are patterns all around them in the universe – some of them seem invisible but once you have an eye to perceive them, the possibilities are endless,” Eddie said.

    “What I hope the children take away from today is that mathematics is found everywhere and it’s for everyone. I think people walk through their life not realising that they swim in this ocean of numbers and shapes that are there to be understood and appreciated.

    “We also fall for the misconception that there’s a certain kind of person who’s a maths person and the rest of us are just normal and can’t comprehend all this. I don’t believe that, I think maths is for everyone, and it’s something we can all embrace.

    “In fact, mathematics is the gateway that allows us to solve these really profound and world-changing problems, like trying to construct a quantum computer!”

    7
    Eddie Woo explaining a card trick.

    Special guests from Victoria

    Among the 200 students visiting the centre was a group of special guests: the Simmons Class, a year 2 class from St Mary of the Cross Primary School in Point Cook, Victoria. Every year, the school names their classes after inspiring themes and individuals – and this year, under the theme of Australian scientists, this class named themselves “Simmons”.

    Earlier this year, Michelle went to see the “Simmons” class in Point Cook, and invited them to visit the centre on Open Day. Many of the children had never been on a plane before.

    The school’s principal, Leon Colla, said that seeing the centre’s research in action was a great experience for the children.

    “I hope that the children will take out of today that science is incredibly important for our future as a country and for them as leaders of the future – and that science is a great pathway to take in education.”

    8
    Simmons class students in the CQC2T labs.

    The school’s teacher, Jennifer Ryan, who had kickstarted the visit by simply emailing Professor Simmons, said interacting with Michelle and the research had created a renewed passion in her students to try new things, be problem solvers, and open up to risk-taking.

    “They’ve learned a lot about quantum physics as a grade 2, and their interest in science has just escalated. Just coming here today I can see how much they’ve picked up on Michelle’s work because they can relate to what they’re seeing.

    “I hope they take out of today that they should dream big. I catch myself looking around, thinking what an incredible opportunity we’ve received – so I hope my students always think that anything’s possible with hard work and putting your mind to it.”

    The positive sentiment was echoed by one student’s dad, James Wetherill, who said his daughter Megan was – to use one of her own words – ‘nerve-cited’ to visit the centre.

    “She was really nervous, and, exceptionally excited as well. She went and bought herself a science kit over the weekend and sat there with her goggles on and said she was practising for coming up today, so she’s loved it, she’s been fully involved, and hopefully it helps guide her moving forward.”

    Another student’s mum, Shella Martin, said the journey her family had been on with Michelle Simmons had been phenomenal.

    “This is basically a dream come true for us. Charlton has always said he was going to be a scientist and mathematician, but he hadn’t seen that come true in any other moment until now.

    “To be able to incorporate this into his education, to show him the potential of the things he can do when he’s older, is just amazing, so we’re just so happy to be able to have this opportunity.”

    9
    Simmons class students.

    Professor Michelle Simmons is delivering the Einstein Lecture as part of Science Week on Tuesday 14 August, 6-7.15pm, at UNSW Sydney. The event is sold out, but you can put your name on a waiting list.

    See the full article here .


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    U NSW Campus

    Welcome to UNSW Australia (The University of New South Wales), one of Australia’s leading research and teaching universities. At UNSW, we take pride in the broad range and high quality of our teaching programs. Our teaching gains strength and currency from our research activities, strong industry links and our international nature; UNSW has a strong regional and global engagement.

    In developing new ideas and promoting lasting knowledge we are creating an academic environment where outstanding students and scholars from around the world can be inspired to excel in their programs of study and research. Partnerships with both local and global communities allow UNSW to share knowledge, debate and research outcomes. UNSW’s public events include concert performances, open days and public forums on issues such as the environment, healthcare and global politics. We encourage you to explore the UNSW website so you can find out more about what we do.

     
  • richardmitnick 10:41 am on February 19, 2018 Permalink | Reply
    Tags: , , , , Quantum computers, Topological superconductors   

    From phys.org: “Unconventional superconductor may be used to create quantum computers of the future” 

    physdotorg
    phys.org

    February 19, 2018

    1
    After an intensive period of analyses the research team led by Professor Floriana Lombardi, Chalmers University of Technology, was able to establish that they had probably succeeded in creating a topological superconductor. Credit: Johan Bodell/Chalmers University of Technology

    With their insensitivity to decoherence, Majorana particles could become stable building blocks of quantum computers. The problem is that they only occur under very special circumstances. Now, researchers at Chalmers University of Technology have succeeded in manufacturing a component that is able to host the sought-after particles.

    Researchers throughout the world are struggling to build quantum computers. One of the great challenges is to overcome the sensitivity of quantum systems to decoherence, the collapse of superpositions. One track within quantum computer research is therefore to make use of Majorana particles, which are also called Majorana fermions. Microsoft, among other organizations, is exploring this type of quantum computer.

    Majorana fermions are highly original particles, quite unlike those that make up the materials around us. In highly simplified terms, they can be seen as half-electron. In a quantum computer, the idea is to encode information in a pair of Majorana fermions separated in the material, which should, in principle, make the calculations immune to decoherence.

    So where do you find Majorana fermions? In solid state materials, they only appear to occur in what are known as topological superconductors. But a research team at Chalmers University of Technology is now among the first in the world to report that they have actually manufactured a topological superconductor.

    “Our experimental results are consistent with topological superconductivity,” says Floriana Lombardi, professor at the Quantum Device Physics Laboratory at Chalmers.

    To create their unconventional superconductor, they started with what is called a topological insulator made of bismuth telluride, Be2Te3. A topological insulator conducts current in a very special way on the surface. The researchers placed a layer of aluminum, a conventional superconductor, on top, which conducts current entirely without resistance at low temperatures.

    “The superconducting pair of electrons then leak into the topological insulator, which also becomes superconducting,” explains Thilo Bauch, associate professor in quantum device physics.

    However, the initial measurements all indicated that they only had standard superconductivity induced in the Bi2Te3 topological insulator. But when they cooled the component down again later, to routinely repeat some measurements, the situation suddenly changed—the characteristics of the superconducting pairs of electrons varied in different directions.

    “And that isn’t compatible at all with conventional superconductivity. Unexpected and exciting things occurred,” says Lombardi.

    “For practical applications, the material is mainly of interest to those attempting to build a topological quantum computer. We want to explore the new physics hidden in topological superconductors—this is a new chapter in physics,” Lombardi says.

    The results were recently published in Nature Communications in a study titled “Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator.”

    See the full article here .

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