Quantum Bayesian Networks

March 23, 2011

To the Rescue, Musketeers! To the Rescue!

Filed under: Uncategorized — rrtucci @ 3:39 am

“All for one, one for all!” (“Tous pour un, un pour tous!”).

RezQu is a family of devices and architecture for a scalable quantum computer based on superconducting phase qubits. RezQu is being developed by a UCSB (U. of California, Santa Barbara) team of swashbuckling musketeers led by Athos Martinis and Porthos Cleland. The team’s intentions are to RezQu Moore’s Law from Cardinal Siliconlieu’s guards. The team recently described their work at the APS (American Physical Society) meeting held on March 2011 at Dallas TX.

The APS meeting had many sessions on diverse quantum information topics. The website for the meeting allows searching by author. A search for “Martinis” revealed that Martinis was a coauthor in 13 of the mini-talks of the conference. Mon Dieu! C’est beaucoup de travail!

Session D27: Superconducting Qubits – Gates and Algorithms had quatre mini-talks on RezQu

  • “Scaling Superconducting Qubits with the ResQu Architecture”, by John Martinis
  • “Experimental demonstration of quantum algorithms on a 4-qubit/5-resonator quantum microprocessor utilizing superconducting qubits in the RezQu architecture”, by Erik Lucero, Rami Barends, Radoslaw Bialczak, Yu Chen, Julian Kelly, Mike Lenander, Matteo Mariantoni, Anthony Megrant, Aaron O’Connell, Peter O’Malley, Daniel Sank, Amit Vainsencher, Hauhoa Wang, James Wenner, Ted White, Yi Yin, Jian Zhao, Andrew Cleland, John Martinis
  • “Quantum Logic Gates for the Rezqu Architecture”, by Joydip Ghosh, Michael Geller (both from U. of Georgia)
  • “Idling error and SWAP/MOVE operation in RezQu architecture for phase qubits”, by Andrei Galiautdinov, Alexander Korotkov (both from U. of Calif. Riverside)

Session D29: Quantum Computing and Simulation I had one mini-talk on planned software for the RezQu platform. Logiciels, ma spécialité!

  • “General-Purpose Quantum Simulation with Prethreshold Superconducting Qubits”, by Emily Pritchett, Colin Benjamin, Andrei Galiautdinov, Michael Geller, Andrew Sornborger, Phillip Stancil, John Martinis

Check out BBC’s reportage on RezQu

Quantum computing device hints at powerful future
By Jason Palmer (BBC, 22 March 2011)

Some excerpts from the BBC article:

The 6cm-by-6cm chip holds nine quantum devices, among them four “quantum bits” that do the calculations.
The team said further scaling up to 10 qubits should be possible this year.

The team’s key innovation was to find a way to completely disconnect – or “decouple” – interactions between the elements of their quantum circuit.
The delicate quantum states that they create must be manipulated, moved, and stored without destroying them.

“It’s a problem I’ve been thinking about for three or four years now, how to turn off the interactions,” UCSB’s John Martinis, who led the research,” told BBC News.
“Now we’ve solved it, and that’s great – but there’s many other things we have to do.”

“There’s already promise to show how this architecture could scale, and we’ve created custom electronics based on cellphone technology which has driven the cost down a lot.

I wrote a previous blog post about UCSB’s QC effort:

Quantum Computing’s American Riviera

March 9, 2011

My Favorite Feynman Quote

Filed under: Uncategorized — rrtucci @ 11:52 am

During one of his famous Feynman Lectures, Feynman said:

I’d like to address those computer scientists and engineers who remain skeptical that quantum mechanics might be relevant to computers and computation. Nature is not classical, dammit! It’s quantum mechanical. Resistance to quantum mechanics is futile; you will be assimilated.

Okay. I made that quote up. I was just trying to spice up my blog. As Richard Lipton once said to me while we shared an office back in our grad school days:

A great blog needs good quotes.


Okay, I made that Lipton story up too. Oh well. The Feynman photo is authentic though. (Both parts of it.)

March 4, 2011

The Greatest Obstacle to Building a Quantum Computer

Filed under: Uncategorized — rrtucci @ 1:12 am

In my opinion, the greatest obstacle to building quantum computers is not Nature, which seems to be quite willing to allow us to build them. It’s the lamentable, needless obstacles that American society is placing in front of those who would love to build them. Aaron O’Connell’s current situation illustrates this point. Aaron, after doing some prize-winning QC work, may end up working at a job that will not tap his expertise and proven talent in QCs and experimental physics.

Check out:

Quantum Physicists “Depressed” and “Isolated,” Says Acclaimed Quantum Physicist
by Anya Kamenetz (Fast Company, March 4, 2011)


Yesterday Aaron O’Connell stunned TED audiences with his description of an experiment three years in the making that for the first time showed quantum delocalization taking place at the level of a physical, visible object. In other words, for his PhD thesis, he got a very small piece of aluminum to be in two places at once. 

When I caught up with the young, spiky-haired O’Connell I congratulated him on this achievement, but he surprised me by sounding pretty dejected. “My nametag says ‘freelance,’” he pointed out. “That’s what you say when you’re unemployed.” O’Connell revealed that he’s considering starting a tech company, maybe to build iPhone apps. “I just want to be around people,” he said, a funny statement for someone who had just shared his discovery with a potential audience of millions. “If you go into any physics lab everybody is depressed and feels isolated. We don’t get any feedback that anybody cares about what we’re doing.”

I mentioned O’Connell’s work before in the following blog post:

Quantum Computing’s American Riviera

March 3, 2011

Intel- The Reluctant Natural

Filed under: Uncategorized — rrtucci @ 5:48 am

If you’ve ever played basketball or baseball or soccer or any other sport, you’ve probably met a naturally talented player. A person who, almost the first time he or she tries, can do the motions of the sport with beautiful fluidity and gracefulness. Less gifted players never perform the motions quite right, no matter how many times they try. It seems to me that in quantum computing, Intel is a naturally gifted player. It’s hard to find a company that is better suited to building a scalable QC. And yet, Intel has never played the QC game. Intel… build it, and they will come.

Intel is the largest semiconductor chip maker in the world. Even though its main headquarters are located in Santa Clara, California (part of Silicon Valley, near San Francisco), it has hundreds of facilities worldwide. Some statistics that convey Intel’s gargantuan size: (statistics taken from Wikipedia and The New York Times)

  • Intel supplies about 80 percent of the PC microprocessor chips worldwide.
  • It has about 100,000 employees, including about 10,000 software engineers
  • Its revenue in 2010 was $43.6 billion
  • Its market capitalization on Feb. 2011 was $122 billion.
  • Intel announced record profits in the last quarter of 2010, and predicted even better performance in the first quarter of 2011.

A company as big and successful as Intel can certainly afford to spend at least a small amount of money on QC research. But they never have, as far as I know. And I think that they should, because quantum computing fits well with their interests. Indeed,

  • Some of the QC hardware realizations that are being tried use Silicon, and Silicon is an Intel specialty.
  • As explained in my previous blog post, most experts believe that Mooore’s Law will hit a brick wall in the next 5 to 10 years. Since its inception, Intel has followed Moore’s Law, so a disruption in that trend should certainly concern them.
  • QCs can do a special type of parallel processing, and Intel is very involved in parallel computing hardware and software.
  • Quantum computing software might fit Intel’s recent efforts to produce a wider range of products, including computer software (they have 10,000 software engineers!)

Intel is to a large extent responsible for the rapid growth of the computer industry in the US. Just think how much could be achieved in quantum computing if this well-disciplined behemoth were to get involved in quantum computing. Also, if Intel were to undertake even a small effort in quantum computing, this would legitimize the field in the eyes of others, and spur other companies to join the QC fray.

Intel already spends a large amount of money on research. According to their website, they currently fund research groups throughout the world working in the following areas. I like lists, so let me cut and paste their impressive list (Ouch, 27 research areas, and no quantum computing):

  1. BioComputing
  2. Circuits
  3. Cloud Computing
  4. Communications
  5. Computation
  6. Cultural Anthropology
  7. Energy
  8. Environment
  9. Internet
  10. Microarchitecture
  11. Mobility
  12. Networking
  13. New User Experiences
  14. Parallel Computing
  15. Personal Energy Systems
  16. Personal Healthcare
  17. Photonics
  18. Robotics
  19. Security/Privacy
  20. Sensing and Perception
  21. Sustainability
  22. Tera-Scale
  23. Transportation
  24. User Experience
  25. User Interface
  26. Visual Computing
  27. Wireless

They also like to fund university research (for example, this year, they announced that they will be contributing $100 million over the next five years to university research projects.) But alas, I’m not aware of any university research project in quantum computing being funded by Intel.

A search of Intel’s website for the keywords “quantum computing” or “quantum computer” yielded very few hits, so if Intel is currently funding any QC research projects, either in-house or at a university, it’s a very minor, poorly publicized effort. At least Microsoft partially funds Station Q at UCSB, a research group dedicated to studying (topological) quantum computing, and Microsoft proudly trumpets this fact in their website.

The Intel STS (Science Talent Search), which was known for its first 57 years of existence as the Westinghouse STS, has been sponsored by Intel since 1998. The STS is a competition between US high school seniors, based on their scientific research projects. In the last two years, at least one student per year with a project in quantum computing has been an STS finalist. I wish Intel would pay attention to the fact that these young scientists find quantum computing interesting. Sometimes the untrammeled curiosity of the young can home-in on scientific questions of great importance.

  • Intel STS 2011 – One of the 40 finalists was Yushi Wang (from Sunset High School, in Oregon), with a project entitled: “Applications of Quantum Ternary Algorithms and Oracles”
    (first to tenth prizes of Intel STS 2011 will be announced on March 15, 2011)

  • Intel STS 2010 – Ninth Place: Yale Wang Fan, (from Catlin Gabel School, in Oregon) with a project entitled: “Adiabatic Quantum Algorithms for Boolean Satisfiability”

Journalist in the popular press often describe quantum mechanics as being a theory that is of interest only to a few experts, and those experts are the only ones that barely understand it, a theory that is incredibly difficult to apply and will only find application in the very distant future. Those journalist seem to want to paint Quantum Mechanics and String Theory with the same brush. But I’m sure that the legions of well-trained scientists and engineers at Intel recognize how silly it is to put Quantum Mechanics and String Theory in the same category.

There is no experimental confirmation of String Theory yet, and, besides, String Theory describes super-high-energy phenomena that can only be observed using a billion dollar machine.

Quantum Mechanics, on the other hand, has been confirmed countless times, and it predicts some lab measurements with unprecedented accuracy. It is the main tool used to explain most of 20th century physics (including solid state physics, statistical mechanics, spectroscopy, laser physics, particle physics, nuclear physics, etc.). In fact, quantum mechanics explains the effects that underpin semiconductor chips, Intel’s bread and butter.

For Intel to refuse to get involved in the next step in the extraordinarily successful career of that theory that we call quantum mechanics, when they owe so much to quantum mechanics already, would be a very illogical move on their part.

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