Tag Archives: quantum information

Using sound to transfer quantum information

It seems sound is becoming more prominent as a means of science data communication (data sonification) and in this upcoming case, data transfer. From a June 5, 2018 news item on ScienceDaily,

Quantum physics is on the brink of a technological breakthrough: new types of sensors, secure data transmission methods and maybe even computers could be made possible thanks to quantum technologies. However, the main obstacle here is finding the right way to couple and precisely control a sufficient number of quantum systems (for example, individual atoms).

A team of researchers from TU Wien and Harvard University has found a new way to transfer the necessary quantum information. They propose using tiny mechanical vibrations. The atoms are coupled with each other by ‘phonons’ — the smallest quantum mechanical units of vibrations or sound waves.

A June 5, 2018 Technical University of Vienna (TU Wien) press release, which originated the news item, explains the work in greater detail,

“We are testing tiny diamonds with built-in silicon atoms – these quantum systems are particularly promising,” says Professor Peter Rabl from TU Wien. “Normally, diamonds are made exclusively of carbon, but adding silicon atoms in certain places creates defects in the crystal lattice where quantum information can be stored.” These microscopic flaws in the crystal lattice can be used like a tiny switch that can be switched between a state of higher energy and a state of lower energy using microwaves.

Together with a team from Harvard University, Peter Rabl’s research group has developed a new idea to achieve the targeted coupling of these quantum memories within the diamond. One by one they can be built into a tiny diamond rod measuring only a few micrometres in length, like individual pearls on a necklace. Just like a tuning fork, this rod can then be made to vibrate – however, these vibrations are so small that they can only be described using quantum theory. It is through these vibrations that the silicon atoms can form a quantum-mechanical link to each other.

“Light is made from photons, the quantum of light. In the same way, mechanical vibrations or sound waves can also be described in a quantum-mechanical manner. They are comprised of phonons – the smallest possible units of mechanical vibration,” explains Peter Rabl. As the research team has now been able to show using simulation calculations, any number of these quantum memories can be linked together in the diamond rod thanks to these phonons. The individual silicon atoms are “switched on and off” using microwaves. During this process, they emit or absorb phonons. This creates a quantum entanglement of different silicon defects, thus allowing quantum information to be transferred.

The road to a scalable quantum network
Until now it was not clear whether something like this was even possible: “Usually you would expect the phonons to be absorbed somewhere, or to come into contact with the environment and thus lose their quantum mechanical properties,” says Peter Rabl. “Phonons are the enemy of quantum information, so to speak. But with our calculations, we were able to show that, when controlled appropriately using microwaves, the phonons are in fact useable for technical applications.”

The main advantage of this new technology lies in its scalability: “There are many ideas for quantum systems that, in principle, can be used for technological applications. The biggest problem is that it is very difficult to connect enough of them to be able to carry out complicated computing operations,” says Peter Rabl. The new strategy of using phonons for this purpose could pave the way to a scalable quantum technology.

Here’s a link to and a citation for the paper,

Phonon Networks with Silicon-Vacancy Centers in Diamond Waveguides by M.-A. Lemonde, S. Meesala, A. Sipahigil, M. J. A. Schuetz, M. D. Lukin, M. Loncar, and P. Rabl. Phys. Rev. Lett. 120 (21), 213603 DOI:https://doi.org/10.1103/PhysRevLett.120.213603 Published 25 May 2018

This paper is behind a paywall.

Quantum computing and more at SXSW (South by Southwest) 2018

It’s that time of year again. The entertainment conference such as South by South West (SXSW) is being held from March 9-18, 2018. The science portion of the conference can be found in the Intelligent Future sessions, from the description,

AI and new technologies embody the realm of possibilities where intelligence empowers and enables technology while sparking legitimate concerns about its uses. Highlighted Intelligent Future sessions include New Mobility and the Future of Our Cities, Mental Work: Moving Beyond Our Carbon Based Minds, Can We Create Consciousness in a Machine?, and more.

Intelligent Future Track sessions are held March 9-15 at the Fairmont.

Last year I focused on the conference sessions on robots, Hiroshi Ishiguro’s work, and artificial intelligence in a  March 27, 2017 posting. This year I’m featuring one of the conference’s quantum computing session, from a March 9, 2018 University of Texas at Austin news release  (also on EurekAlert),

Imagine a new kind of computer that can quickly solve problems that would stump even the world’s most powerful supercomputers. Quantum computers are fundamentally different. They can store information as not only just ones and zeros, but in all the shades of gray in-between. Several companies and government agencies are investing billions of dollars in the field of quantum information. But what will quantum computers be used for?

South by Southwest 2018 hosts a panel on March 10th [2018] called Quantum Computing: Science Fiction to Science Fact. Experts on quantum computing make up the panel, including Jerry Chow of IBM; Bo Ewald of D-Wave Systems; Andrew Fursman of 1QBit; and Antia Lamas-Linares of the Texas Advanced Computing Center at UT Austin.

Antia Lamas-Linares is a Research Associate in the High Performance Computing group at TACC. Her background is as an experimentalist with quantum computing systems, including work done with them at the Centre for Quantum Technologies in Singapore. She joins podcast host Jorge Salazar to talk about her South by Southwest panel and about some of her latest research on quantum information.

Lamas-Linares co-authored a study (doi: 10.1117/12.2290561) in the Proceedings of the SPIE, The International Society for Optical Engineering, that published in February of 2018. The study, “Secure Quantum Clock Synchronization,” proposed a protocol to verify and secure time synchronization of distant atomic clocks, such as those used for GPS signals in cell phone towers and other places. “It’s important work,” explained Lamas-Linares, “because people are worried about malicious parties messing with the channels of GPS. What James Troupe (Applied Research Laboratories, UT Austin) and I looked at was whether we can use techniques from quantum cryptography and quantum information to make something that is inherently unspoofable.”

Antia Lamas-Linares: The most important thing is that quantum technologies is a really exciting field. And it’s exciting in a fundamental sense. We don’t quite know what we’re going to get out of it. We know a few things, and that’s good enough to drive research. But the things we don’t know are much broader than the things we know, and it’s going to be really interesting. Keep your eyes open for this.

Quantum Computing: Science Fiction to Science Fact, March 10, 2018 | 11:00AM – 12:00PM, Fairmont Manchester EFG, SXSW 2018, Austin, TX.

If you look up the session, you will find,

Quantum Computing: Science Fiction to Science Fact

Quantum Computing: Science Fiction to Science Fact

Speakers

Bo Ewald

D-Wave Systems

Antia Lamas-Linares

Texas Advanced Computing Center at University of Texas

Startups and established players have sold 2000 Qubit systems, made freely available cloud access to quantum computer processors, and created large scale open source initiatives, all taking quantum computing from science fiction to science fact. Government labs and others like IBM, Microsoft, Google are developing software for quantum computers. What problems will be solved with this quantum leap in computing power that cannot be solved today with the world’s most powerful supercomputers?

[Programming descriptions are generated by participants and do not necessarily reflect the opinions of SXSW.]

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Primary Entry: Platinum Badge, Interactive Badge

Secondary Entry: Music Badge, Film Badge

Format: Panel

Event Type: Session

Track: Intelligent Future

Level: Intermediate

I wonder what ‘level’ means? I was not able to find an answer (quickly).

It’s was a bit surprising to find someone from D-Wave Systems (a Vancouver-based quantum computing based enterprise) at an entertainment conference. Still, it shouldn’t have been. Two other examples immediately come to mind, the TED (technology, entertainment, and design) conferences have been melding technology, if not science, with creative activities of all kinds for many years (TED 2018: The Age of Amazement, April 10 -14, 2018 in Vancouver [Canada]) and Beakerhead (2018 dates: Sept. 19 – 23) has been melding art, science, and engineering in a festival held in Calgary (Canada) since 2013. One comment about TED, it was held for several years in California (1984, 1990 – 2013) and moved to Vancouver in 2014.

For anyone wanting to browse the 2018 SxSW Intelligent Future sessions online, go here. or wanting to hear Antia Lamas-Linares talk about quantum computing, there’s the interview with Jorge Salazar (mentioned in the news release),

Nanodevices and quantum entanglement

A May 30, 2016 news item on phys.org introduces a scientist with an intriguing approach to quantum computing,

Creating quantum computers which some people believe will be the next generation of computers, with the ability to outperform machines based on conventional technology—depends upon harnessing the principles of quantum mechanics, or the physics that governs the behavior of particles at the subatomic scale. Entanglement—a concept that Albert Einstein once called “spooky action at a distance”—is integral to quantum computing, as it allows two physically separated particles to store and exchange information.

Stevan Nadj-Perge, assistant professor of applied physics and materials science, is interested in creating a device that could harness the power of entangled particles within a usable technology. However, one barrier to the development of quantum computing is decoherence, or the tendency of outside noise to destroy the quantum properties of a quantum computing device and ruin its ability to store information.

Nadj-Perge, who is originally from Serbia, received his undergraduate degree from Belgrade University and his PhD from Delft University of Technology in the Netherlands. He received a Marie Curie Fellowship in 2011, and joined the Caltech Division of Engineering and Applied Science in January after completing postdoctoral appointments at Princeton and Delft.

He recently talked with us about how his experimental work aims to resolve the problem of decoherence.

A May 27, 2016 California Institute of Technology (CalTech) news release by Jessica Stoller-Conrad, which originated the news item, proceeds with a question and answer format,

What is the overall goal of your research?

A large part of my research is focused on finding ways to store and process quantum information. Typically, if you have a quantum system, it loses its coherent properties—and therefore, its ability to store quantum information—very quickly. Quantum information is very fragile and even the smallest amount of external noise messes up quantum states. This is true for all quantum systems. There are various schemes that tackle this problem and postpone decoherence, but the one that I’m most interested in involves Majorana fermions. These particles were proposed to exist in nature almost eighty years ago but interestingly were never found.

Relatively recently theorists figured out how to engineer these particles in the lab. It turns out that, under certain conditions, when you combine certain materials and apply high magnetic fields at very cold temperatures, electrons will form a state that looks exactly as you would expect from Majorana fermions. Furthermore, such engineered states allow you to store quantum information in a way that postpones decoherence.

How exactly is quantum information stored using these Majorana fermions?

The fascinating property of these particles is that they always come in pairs. If you can store information in a pair of Majorana fermions it will be protected against all of the usual environmental noise that affects quantum states of individual objects. The information is protected because it is not stored in a single particle but in the pair itself. My lab is developing ways to engineer nanodevices which host Majorana fermions. Hopefully one day our devices will find applications in quantum computing.

Why did you want to come to Caltech to do this work?

The concept of engineered Majorana fermions and topological protection was, to a large degree, conceived here at Caltech by Alexei Kiteav [Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics] who is in the physics department. A couple of physicists here at Caltech, Gil Refeal [professor of theoretical physics and executive officer of physics] and Jason Alicea [professor of theoretical physics], are doing theoretical work that is very relevant for my field.

Do you have any collaborations planned here?

Nothing formal, but I’ve been talking a lot with Gil and Jason. A student of mine also uses resources in the lab of Harry Atwater [Howard Hughes Professor of Applied Physics and Materials Science and director of the Joint Center for Artificial Photosynthesis], who has experience with materials that are potentially useful for our research.

How does that project relate to your lab’s work?

There are two-dimensional, or 2-D, materials that are basically very thin sheets of atoms. Graphene [emphasis mine]—a single layer of carbon atoms—is one example, but you can create single layer sheets of atoms with many materials. Harry Atwater’s group is working on solar cells made of a 2-D material. We are thinking of using the same materials and combining them with superconductors—materials that can conduct electricity without releasing heat, sound, or any other form of energy—in order to produce Majorana fermions.

How do you do that?

There are several proposed ways of using 2-D materials to create Majorana fermions. The majority of these materials have a strong spin-orbit coupling—an interaction of a particle’s spin with its motion—which is one of the key ingredients for creating Majoranas. Also some of the 2-D materials can become superconductors at low temperatures. One of the ideas that we are seriously considering is using a 2-D material as a substrate on which we could build atomic chains that will host Majorana fermions.

What got you interested in science when you were young?

I don’t come from a family of scientists; my father is an engineer and my mother is an administrative worker. But my father first got me interested in science. As an engineer, he was always solving something and he brought home some of the problems he was working. I worked with him and picked it up at an early age.

How are you adjusting to life in California?

Well, I like being outdoors, and here we have the mountains and the beach and it’s really amazing. The weather here is so much better than the other places I’ve lived. If you want to get the impression of what the weather in the Netherlands is like, you just replace the number of sunny days here with the number of rainy days there.

I wish Stevan Nadj-Perge good luck!