Monthly Archives: July 2017

July 12, 2017 It may be possible to control a quantum computer over the internet without revealing what you are calculating, thanks to the many possible ways that information can flow through a computation. That's the conclusion of researchers in Singapore and Australia who studied the measurement-based model of quantum computing, reported 11 July in the open-access journal Physical Review X. Credit: Timothy Yeo / Centre for Quantum Technologies, National University of Singapore

Here's the scenario: you have sensitive data and a problem that only a quantum computer can solve. You have no quantum devices yourself. You could buy time on a quantum computer, but you don't want to give away your secrets. What can you do?

Writing in Physical Review X on 11 July, researchers in Singapore and Australia propose a way you could use a quantum computer securely, even over the internet. The technique could hide both your data and program from the computer itself. Their work counters earlier hints that such a feat is impossible.

The scenario is not far-fetched. Quantum computers promise new routes to solving problems in cryptography, modelling and machine learning, exciting government and industry. Such problems may involve confidential data or be commercially sensitive.

Technology giants are already investing in building such computersand making them available to users. For example, IBM announced on 17 May this year that it is making a quantum computer with 16 quantum bits accessible to the public for free on the cloud, as well as a 17-qubit prototype commercial processor.

Seventeen qubits are not enough to outperform the world's current supercomputers, but as quantum computers gain qubits, they are expected to exceed the capabilities of any machine we have today. That should drive demand for access.

"We're looking at what's possible if you're someone just interacting with a quantum computer across the internet from your laptop. We find that it's possible to hide some interesting computations," says Joseph Fitzsimons, a Principal Investigator at the Centre for Quantum Technologies (CQT) at the National University of Singapore and Associate Professor at Singapore University of Technology and Design (SUTD), who led the work.

Quantum computers work by processing bits of information stored in quantum states. Unlike the binary bits found in our regular (i.e., classical) computers, each a 0 or 1, qubits can be in superpositions of 0 and 1. The qubits can also be entangled, which is believed to be crucial to a quantum computer's power.

The scheme designed by Fitzsimons and his colleagues brings secrecy to a form of quantum computing driven by measurements.

In this scheme, the quantum computer is prepared by putting all its qubits into a special type of entangled state. Then the computation is carried out by measuring the qubits one by one. The user provides step-wise instructions for each measurement: the steps encode both the input data and the program.

Researchers have shown previously that users who can make or measure qubits to convey instructions to the quantum computer could disguise their computation. The new paper extends that power to users who can only send classical bits - i.e. most of us, for now.

This is surprising because some computer science theorems imply that encrypted quantum computation is impossible when only classical communication is available.

The hope for security comes from the quantum computer not knowing which steps of the measurement sequence do what. The quantum computer can't tell which qubits were used for inputs, which for operations and which for outputs.

"It's extremely exciting. You can use this unique feature of the measurement-based model of quantum computingthe way information flows through the stateas a crypto tool to hide information from the server," says team member Tommaso Demarie of CQT and SUTD.

Although the owner of the quantum computer could try to reverse engineer the sequence of measurements performed, ambiguity about the role of each step leads to many possible interpretations of what calculation was done. The true calculation is hidden among the many, like a needle in a haystack.

The set of interpretations grows rapidly with the number of qubits. "The set of all possible computations is exponentially large - that's one of the things we prove in the paperand therefore the chance of guessing the real computation is exponentially small," says Fitzsimons. One question remains: could meaningful computations be so rare among all the possible ones that the guessing gets easier? That's what the researchers need to check next.

Nicolas Menicucci at the Centre for Quantum Computation and Communication Technology at RMIT University in Melbourne, Australia, and Atul Mantri at SUTD, are coauthors on the work.

"Quantum computers became famous in the '90s with the discovery that they could break some classical cryptography schemesbut maybe quantum computing will instead be known for making the future of cloud computing secure," says Mantri.

Explore further: Refrigerator for quantum computers discovered

More information: Atul Mantri et al, Flow Ambiguity: A Path Towards Classically Driven Blind Quantum Computation, Physical Review X (2017). DOI: 10.1103/PhysRevX.7.031004

The global race towards a functioning quantum computer is on. With future quantum computers, we will be able to solve previously impossible problems and develop, for example, complex medicines, fertilizers, or artificial ...

A team of researchers from Australia and the UK have developed a new theoretical framework to identify computations that occupy the 'quantum frontier'the boundary at which problems become impossible for today's computers ...

While technologies that currently run on classical computers, such as Watson, can help find patterns and insights buried in vast amounts of existing data, quantum computers will deliver solutions to important problems where ...

Researchers have succeeded in combining the power of quantum computing with the security of quantum cryptography and have shown that perfectly secure cloud computing can be achieved using the principles of quantum mechanics. ...

Quantum computersa possible future technology that would revolutionize computing by harnessing the bizarre properties of quantum bits, or qubits. Qubits are the quantum analogue to the classical computer bits "0" and "1." ...

IBM has announced its plans to begin offering the world's first commercial universal quantum-computing servicecalled IBM Q, the system will be made available to those who wish to use it for a fee sometime later this year. ...

(Phys.org)When researchers deposit a drop of fluid containing thousands of free-swimming, genetically engineered E. coli onto an array of micromotors, within minutes the micromotors begin rotating. Some of the individual ...

Scientists at the University of Copenhagen have developed a hands-on answer to a challenge linked to Heisenberg's Uncertainty Principle. The researchers used laser light to link caesium atoms and a vibrating membrane. The ...

Information technologies of the future will likely use electron spinrather than electron chargeto carry information. But first, scientists need to better understand how to control spin and learn to build the spin equivalent ...

Researchers have developed a fast and practical molecular-scale imaging technique that could let scientists view never-before-seen dynamics of biological processes involved in neurodegenerative diseases such as Alzheimer's ...

(Phys.org)A pair of researchers at Brown University has found that it is possible to induce a drop of fluid to emit smaller droplets in a way that resembles the planet Saturn with its rings. In their paper published in ...

Large-scale quantum computers, which are an active pursuit of many university labs and tech giants, remain years away. But that hasn't stopped some scientists from thinking ahead, to a time when quantum computers might be ...

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Why you might trust a quantum computer with secretseven over ... - Phys.Org

There had been times where the HTTPS protocol was deemed secure. Now gone. We live in times where Bitcoins blockchain is deemed secure, and unless 51% attack happens it is safe haven to store wealth in Bitcoin. Yet, in a very near future, that is about to change.

Quantum computing modelled by Ben Larzinski.

In the last decade, the scientists from US, Canada and Australia have progressed by leaps and bounds in the field of quantum comping. First quantum computers are already being built by Canadian D-WAVE. These luckily have one defect cannot kill Bitcoin. Yikes!

Worse threat to Bitcoin however is the cooperation of NASA, CIA (read NSA) and Google. The three are building a special 50-qubit strong quantum computer of their own, which will kill Bitcoin. Have they succeeded yet? Unfortunately we will get to know after its too late. Google, however is deploying their 49-qubit (weak) version by the end of 2017

We will know after its late. Like with the NSAs exploit ETERNALBLUE leaked by ShadowBrokers hacker group, which gave birth to a massive cryptocurrency botnet in May 2017.

Losing all our cryptocurrency holdings in a brink of the moment is something that can happen. Why is this possible? 50-qubit quantum computers can use Shors Algorithm and Grover Algorithm to polynomially reduce the difficulty of all of the commonly-used public-key algorithms. This includes RSA, DSA, DH, and all forms of elliptic-curve cryptography. Instead of taking years to break the cipher, it will take hours.

https://droplex.org/ico.php

Introducing Droplex, the experts behind cryptocurrency blockchain using quantum resistant encryption.

When quantum computers come, you will welcome them with an open hug.

Droplex develops a Public-key blockchain that is secure against QC. Their team together with most Bitcoin experts have agreed on using Lamport signatures. The question however was in deploying it. Because reaching consensus for a much smaller disruption such as blocksize change is a heroic task, the Droplex team has decided to save the day on their own! Developers are creating their own cryptocurrency running on a quantum resistant blockchain.

Droplex team includes experts from the field of Quantum Computing from the US and Australia. In whitepaper, they explain how Lamport-Diffie and Winternitz one-time-signatures can be leveraged to create quantum resistant blockchain.

Droplex team precisely follows their roadmap:

Excerpt from:

Quantum Computer, hug me openly! DROPLEX ICO - newsBTC

Scientists have long dreamed of developing quantum computers, machines that rely on arcane laws of physics to perform tasks far beyond the capability of todays strongest supercomputers. In theory such a machine could create mathematical models too complex for standard computers, vastly extending the range and accuracy of weather forecasts and financial market predictions, among other things. They could simulate physical processes such as photosynthesis, opening new frontiers in green energy. Quantum computing could also jolt artificial intelligence to a vastly higher level of sophistication: If IBMs Watson can already win at Jeopardy! and make some medical diagnoses, imagine what an enormously smarter version could do.

But to realize those visions, scientists first have to figure out how to actually build a quantum computer that can perform more than the simplest operations. They are now getting closer than ever, with IBM in May announcing its most complex quantum system so far and Google saying it is on track this year to unveil a processor with so-called quantum supremacy capabilities no conventional computer can match.

Small systems exist, but the next steps in the race to make them bigger will have to determine whether quantum computers can deliver on their potential. Scientists and industry players have focused largely on one of two approaches. One cools loops of wire to near 273.15 degrees Celsius, or absolute zero, turning them into superconductors where current flows with virtually no resistance. The other relies on trapped ionscharged atoms of the rare earth element ytterbium held in place in a vacuum chamber by laser beams and manipulated by other lasers. The oscillating charges (in both the wires and the trapped ions) function as quantum bits, or qubits, which can be harnessed to carry out the computers operations.

Quantum leaps

The trick to either approach is figuring out how to get from already demonstrated systemscontaining just a few qubits to ones that can handle the hundreds or thousands required for the kind of heavy lifting that quantum technology seems to promise. Last year IBM made a five-qubit quantum processor available to developers, researchers and programmers for experimentation via its cloud portal. The company has made significant progress since then, revealing in May that it has upgraded its cloud-based quantum computer to a 16-qubit processorand created a more tightly engineered 17-qubit processor that could be the basis for commercial systems. Both are based on the wire-loop superconducting circuits, as is Googles 20-qubit processor, which the company announced at a conference in Munich, Germany, on June 22. Alan Ho, an engineer in Googles Quantum Artificial Intelligence Lab, told the conference his company expects to achieve quantum supremacy with a 49-qubit chip by the end of this year.

Those numbers may not seem impressive. But a qubit is much more powerful than the kind of bit that serves as the smallest unit of data in a conventional computer. Those bits are based on the flow of electrical current, and make up the digital language in which all computing functions: Off means 0 and on means 1, and those two states encode all of the computers operations. Qubits, however, are not based on yes/no electrical switchesbut rather on a particles quantum properties, such as the direction in which an electron spins. And in the quantum world a particle can simultaneously exist in a variety of states more complex than simply on/off a phenomenon known as superposition. You can have heads, you can have tails, but you can also have any weighted superposition. You can have 70-30 heads-tails, says Christopher Monroe, a physicist at the University of Maryland, College Park, and founder of IonQ, a start-up working on building a quantum computer with trapped ions.

The more-than-binary ability to occupy multiple states at once allows qubits to perform many calculations simultaneously, vastly magnifying their computing power. That power grows exponentially with the number of qubits. So at somewhere around 49 or 50 qubits, quantum computers reach the equivalent of about 10 quadrillion bits and become capable of calculations no classical computer could ever match, says John Preskill, a theoretical physicist at California Institute of Technology. Whether they will be doing useful things is a different question, he says.

Both superconducting circuits and trapped ions have a good shot at hitting that fiftyish-qubit threshold, says Jerry Chow, manager of experimental quantum computing at IBM T. J. Watson Research Center in Yorktown Heights, N.Y. Conventional thinking would suggest that more qubits means more power but Chow notes its not just about the number of qubits. He is more focused on the number and quality of calculations the machine can perform, a metric he calls quantum volume. That includes additional factors such as how fast the qubits can perform the calculations and how well they avoid or correct for errors that can creep in. Some of those factors can work against one another; adding more qubits, for instance, can increase the rate of errors as information passes down the line from one qubit to another. As a community we should all be focusingno matter whether were working on superconducting qubits or trapped ions or whatever on pushing this quantum volume higher and higher so we can really make more and more powerful quantum processors and do things that we never thought of, Chow says.

Better, not bigger

Monroe recently compared his five-qubit trapped ion system with IBMs five-qubit processor by running the same simple algorithms on both, and found the performance comparable. The biggest difference, he says, is that the trapped ions are all connected to one another via electromagnetic forces: Wiggle one ion in a string of 30 and every other ion reacts, making it easy to quickly and accurately pass information among them. In the wire-loop superconductor circuit only some qubits are connected, which makes passing information a slower process that can introduce errors.

One advantage of superconducting circuits is that they are easy to build using the same processes that make computer chips. They perform a computers basic logic gate operations that is, adding, subtracting or otherwise manipulating the bits in billionths of a second. On the other hand, qubits in this type of system hold their quantum state for only milliseconds thousandths of a second so any operation must be completed in that time.

Trapped ions, by contrast, retain their quantum states for many seconds sometimes even minutes or hours. But the logic gates in such a system run about 1,000 times slower than in superconductor-based quantum computing. That speed reduction probably does not matter in simple operations with just a few qubits, Monroe says. But it could become a problem for getting an answer in a reasonable amount of time as the number of qubits increases. For superconducting qubits, rising numbers may mean a struggle to connect them together.

And increasing the number of qubits, no matter what technology they are used with, makes it harder to connect and manipulate them because that must be done while keeping them isolated from the rest of the world so they will maintain their quantum states. The more atoms or electrons are grouped together in large numbers, the more the rules of classical physics take over and the less significant the quantum properties of the individual atoms become to how the whole system behaves. When you make a quantum system big, it becomes less quantum, Monroe says.

Chow thinks quantum computers will become powerful enough to do at least something beyond the capability of classical computers possibly a simulation in quantum chemistry within about five years. Monroe says it is reasonable to expect systems containing a few thousand qubits in a decade or so. To some extent, Monroe says, researchers will not know what they will be able to do with such systems until they figure out how to build them.

Preskill, who is 64, says he thinks he will live long enough to see quantum computers have an impact on society in the way the internet and smartphones have although he cannot predict exactly what that impact will be. These quantum systems kind of speak a language that digital systems dont speak, he says. We know from history that we just dont have the imagination to anticipate where new information technologies can carry us.

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Quantum computers compete for supremacy - Salon