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Tag archives: quantum computers

Spies are keen on quantum computing, claims Washington Post

By Hamish Johnston

An article in the Washington Post claims that the US National Security Agency (NSA) is funding research into how quantum computers could be used to crack cryptography systems. While the article claims to be based on leaked secret documents, the revelation doesn’t seem to surprise several of the physicists quoted in the piece.

Scott Aaronson of the Massachusetts Institute of Technology (MIT) says that it’s unlikely that the NSA project is much further ahead of public quantum-computing research. His MIT colleague Seth Lloyd adds that it could be five years or more before the NSA or anyone else creates a quantum computer capable of breaking cryptographic systems.

Interestingly, Lloyd alludes to a space-race-like rivalry between the US, EU and Switzerland that is driving the development of code-busting quantum computers.

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Quantum hackers foiled – for now

By Hamish Johnston

QKD is a popular quantum-cryptography technique that is already being used commercially. It allows two parties, usually called Alice and Bob,  to exchange an encryption key, secure in the knowledge that the key will not have been read by an eavesdropper (Eve). This guarantee is possible because the key is transmitted in terms of quantum bits (qubits) of information, which if intercepted and read are changed irrevocably, thus revealing the actions of Eve.

QKD cannot be cracked if it is implemented using equipment that behaves exactly as expected. Qubits are normally transmitted as single photons, for example, and therefore Alice and Bob must be equipped with single-photon detectors. The problem is that these detectors are not perfect and by simply shining a bright laser at a detector, Eve can trick it into thinking that it has detected a single photon even though that photon has been read by her.

While physicists have come up with several ways of thwarting such attacks, these tend to complicate the QKD process so as to make it impractical. Now, two independent teams of physicists have demonstrated aspects of a new scheme called measurement device independent QKD (MDI-QKD) that seems to close the loophole.

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Quantum communication in the back of a pick-up

Thomas Jennewein and his quantum receiver, which will soon hit the streets of Waterloo

Thomas Jennewein and his quantum receiver will soon hit the streets of Waterloo.

By Hamish Johnston

I’m back from my trip to Waterloo, Ontario – Canada’s “Quantum Valley” – but there is still so much to tell. The photograph above is of Thomas Jennewein of the Institute for Quantum Computing (IQC), who took me on a tour of his lab earlier this week.

Jennewein is standing next to a quantum receiver that he and his colleagues will soon be bolting to a pick-up truck and driving around Waterloo. The plan is to receive quantum communications from a light source that’s on the roof of one of IQC’s buildings. The ultimate goal of the research is to deploy quantum receivers (and transmitters) in space to create a global quantum-communication network.

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Life inside the Perimeter

Blackboards and equations galore at the PI

Blackboards and equations galore at the PI.

By Hamish Johnston in Canada’s Quantum Valley

Today I am living the dream, at least for many theoretical physicists. I have my very own office at the Perimeter Institute (PI) for Theoretical Physics in Waterloo, Ontario. It comes complete with free coffee, a blackboard pre-loaded with equations and access to some of the world’s top physicists.

This morning I spoke to Daniel Gottesman, who if I am not mistaken was the first PI faculty member to work on quantum information after joining in 2002. His speciality is quantum error correction and we had a fantastic chat about the directions in which quantum computing could go in the future.

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Entering the quantum world

Not a black hole in sight: Raymond Laflamme in one of the IQC labs. The machine behind him makes diamonds for quantum computing experiments

Not a black hole in sight: Raymond Laflamme in one of the IQC labs. The machine behind him makes diamonds for quantum-computing experiments.

By Hamish Johnston in Canada’s Quantum Valley

“We have entered the quantum world and we can control it” is how Raymond Laflamme characterizes the current quantum renaissance that is sweeping across many fields of physics. Laflamme is director of the Institute for Quantum Computing (IQC) at Canada’s University of Waterloo and he began his career at the University of Cambridge as a student of Stephen Hawking, working on cosmology.

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A ‘unique’ quantum research centre

Vadim Makarov with a few old friends

Vadim Makarov with a few old friends.

By Hamish Johnston in Canada’s Quantum Valley

“There’s no place like this in the world,” said Vadim Makarov (above) as we walked up to his lab at the Institute for Quantum Computing (IQC) at Canada’s University of Waterloo. What’s unique about the place, according to Makarov and others I spoke to in Waterloo, is that it brings together a diverse group of researchers (physicists, computer scientists, mathematicians, engineers, etc) in one place to develop quantum-information technology.

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High-sticking in the Quantum Valley

Keep your stick on the ice! How to give a talk at PI

Keep your stick on the ice! How to give a talk at PI.

By Hamish Johnston in Canada’s Quantum Valley

I had a fantastic day today touring Canada’s “Quantum Valley”, which is what people are starting to call the region surrounding the University of Waterloo in Ontario. Waterloo is an hour’s drive west of Toronto and home to the Perimeter Institute for Theoretical Physics (PI) and the Institute for Quantum Computing (IQC). There is also a small but growing cluster of quantum technology start-ups that have spun out of the university.

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Condensed-matter cosmology and spin wires

Waterloo, here I come (Courtesy: IQC)

Waterloo, here I come. (Courtesy: IQC)

By Hamish Johnston at the 2013 CAP Congress in Montreal

Yesterday morning I was back at the University of Montreal for more physics at the Canadian Association of Physicists Congress. I started off the morning with a bit of quantum cosmology and quantum gravity with a distinct hint of condensed-matter physics.

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Google and NASA acquire a D-Wave quantum computer

D-Wave's Geordie Rose with one of the firm's quantum computers. (Courtesy: D-Wave)

D-Wave’s Geordie Rose with one of the firm’s quantum computers. (Courtesy: D-Wave)

By Hamish Johnston

Canada’s D-Wave Systems is installing one of its quantum computers at NASA’s Ames Research Center in California. The new 512-qubit system – dubbed D-Wave Two – will be used by NASA, Google and the Universities Space Research Association (USRA) to investigate how quantum computers could be used to solve a range of different problems. According to Vancouver-based D-Wave, the computer will be available for use in the third quarter of this year.

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When will quantum communications blast off?

Will quantum communications be sent to the ISS?

Will quantum communications be sent to the ISS? (Courtesy: NASA)

By Hamish Johnston

I think it’s safe to say that quantum communications between satellites and ground-based stations should be possible. Optical signals have already been sent 144 km through the air between ground stations at sea level. More recently, quantum communications have been achieved between an aircraft in flight and a ground station 20 km distant.

While quantum communications have been sent comparable distances via optical fibre, it’s unlikely that the fragile single photons used in such missives would survive an ocean crossing unscathed. Therefore if technologies such as quantum key distribution cryptography are to become truly practical, satellites must be involved.

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