Quantum effects in biosystems Discover Magazine In Discover (February 2009), Mark Anderson reviews contemporary experiments in biophysics that explore the influence of quantum effects in living systems: "Could quantum mechanisms be driving some of the most elegant and inexplicable processes of life? For years experts doubted it: Quantum phenomena typically reveal themselves only in lab settings, in vacuum chambers chilled to near absolute zero. Biological systems are warm and wet. Most researchers thought the thermal noise of life would drown out any quantum weirdness that might rear its head. Yet new experiments keep finding quan­­tum processes at play in biological systems, says Christopher Altman, alumni researcher from European futurist think tank Starlab. With the advent of powerful new tools like femtosecond (10^-15 second) lasers and nanoscale-precision positioning, life’s quantum dance is finally coming into view."

The Unmanned Air Force USAF In Network World and concurrent Slashdot updates, Lt. Gen. Seip discusses the future of unmanned combat aerial vehicles. "How important have unmanned aircraft become to the US military? Well, how's this: the Air Force says next year it will acquire more unmanned aircraft than manned aircraft. Air Force Lt. Gen. Norman Seip this week said the service is "all in" when it comes to developing unmanned systems and aircraft.' Next year, the Air Force will procure more unmanned aircraft than manned aircraft,' the general said. 'I think that makes a very pointed statement about our commitment to the future of unmanned aircraft, and what it brings to the fight in meeting the requirements of combatant commanders.'"

Convergence⁰⁸  Mountain View  " From 15-16 November 2008 – the world's most dangerous ideas will collide in Mountain View, California. Convergence⁰⁸ examines the world-changing possibilities of nanotechnology and the life-changing promises of biotechnology. It is the premier forum for debate and exploration of cognitive technology ethics – and ground zero of the past and future information technology revolution. Convergence⁰⁸ is an innovative, lively 'unconference' – the first and only unclassified forum dedicated solely to the convergence of NBIC – nano-, bio-, information and cognitive – technology developments." 

As my own UNISCA First Committee chair report to the General Assembly – "Converging Technologies: The Future of the Global Information Society" – focused specifically upon these long-term technological and cultural challenges, which we will have to confront both as a society and as a species – I have high hopes that this meeting will provide a stimulating, and unparalleled, open venue for exploration of novel ideas, discussion of alternative paradigms, and fertile grounds for brainstorming original, innovative solutions. My congratulations to the initiative of the conference organizers. I look forward to reporting back upon conclusion of the conference, as there has been an open conference wiki set up at the conference website to contribute novel ideas to the discussion.

Time in Quantum Mechanics Perimeter Institute The Clock and the Quantum focuses on conceptual and technical issues concerning the role of time in quantum theory – including quantum correlations in time, histories approaches, pre- and post-selected ensembles, time and quantum measurement, and causality under the framework of quantum theory. 

Lee Smolin discusses cosmological inflation, the problem of initial conditions, and the interpretation of the "wavefunction of the universe." Lev Vaidman provides a review of the two state vector formalism, which considers backwards-evolving quantum states. Noriyuki Hatakenaka presents a new scheme for testing macrorealism without statistical treatments by combining Leggett-Garg and Greenberger-Horne-Zeilinger (GHZ) inequalities, i.e. a temporal GHZ test using quantum correlations in time. Lucian Ionescu outlines an "upgrade" of the Feynman path integral formalism – where qubits, instead of complex amplitudes – are associated within elementary transitions of a causal network structure.

The conference is first in a series of foundations conferences organized under joint collaboration between the Perimeter Institute and three Australian national universities.

From Qubits to Black Holes Technion | Macquarie University "Asher Peres (1934-2005), was an Israeli scientist who is widely considered to be one of the pioneering founders of quantum information science. A student of Nathan Rosen, (the “R” of EPR), Asher codiscovered quantum teleportation, a time-reversal test for quantum entanglement, and published numerous works on the foundations of quantum science. His research legacy continues through his many research collaborators, students, textbooks and research papers."

The Technion (Israel), and Macquarie University (Australia), will host the inaugural Asher Peres International Physics School 2008, for senior undergraduates and junior postgraduates in a series of lectures ranging from quantum mechanics, theory and experiments, through to quantum gravity. Held over five days, from November 17-22 (2008), in the historic environs at Chowder Bay on Sydney Harbor, the School will feature lectures from leading scientists from around the world, including Sir Peter Knight, Artur Ekert, Christian Kurtsiefer, Chris Fuchs, Bei Lok Hu, Jason Twamley, Daniel Terno, Gavin Brennen, Alexei Gilchrist, James Rabeau, and James Cresser.

Progress in Quantum Computing IQSA | LT₂₅ | Lorentz Center – I've recently returned from a series of international conferences and workshops on superconductivity, quantum computation, entanglement and quantum coherence. In Sopot, Poland at the International Conference on Quantum Structures, much of the week was spent in long walks on the shores of the Baltic Sea, holding intense discussions on quantum information theory with Lev Levitin, who will be hosting the IQSA meeting at MIT in two years. We also continued ongoing research with Roman Zapatrin (Starlab) to advance the development of adaptive quantum networks for applications in fault-tolerant quantum computation, associative processing and pattern recognition.

Following IQSA, I moved on to the 25^th triennial International Conference on Low-temperature Condensed Matter Physics, where I met with Keith Schwab following presentation of his group's recent experiments with nanomechanical resonators to probe the boundaries of quantum and classical regimes, as well as discussing present and upcoming experiments in superconducting flux qubit systems with Yasu Nakamura, John Clarke, Robert Schoelkopf, and John Martinis.

Upon conclusion of LT₂₅, a satellite conference on Quantum Decoherence in Quantum Information Systems was held at the Lorentz Center, where I met with Vlatko Vedral to discuss long-term research initiatives in multipartite and macroscopic entanglement in condensed matter systems. Jasper van Wezel presented a review of the limits to quantum behavior related to spontaneous symmetry breaking – summarizing recent results on the quantum to classical transition, and future experiments which may elucidate the process of wavefunction collapse. Dirk Bouwmeester was generous enough to offer a tour of the experimental laboratory setup for the MiniGRAIL gravitational wave detector, which has just undergone several modifications, including improvements to the antenna, cryogenic cool-down systems, improved shielding, redesign of the capacitive transducer and fabrication of a new two-stage SQUID module for more stable operation at low temperatures.

Space QUEST: Experiments with quantum entanglement in space Vienna | ESA | ISS In a recent submission to the arXiv,  Zeilinger's group at University of Vienna, Austria has proposed an experiment—Space-QUEST, Quantum Entanglement Science and Technology—for space-to-ground, entangled-photon Bell Inequality violation measurements to verify quantum nonlocality at distances over thousands of kilometers, in a joint operation between the International Space Station and a ground observatory in the European Union.

Entanglement and nonlocality have been pivotal controversies since the birth of quantum mechanics—Einstein's "spooky action at a distance" implies simultaneous, nonlocal correlations between separate entangled particles. J. S. Bell was the first to confirm the phenomenon experimentally in 1964.

Further refinements and increasing precision in succeeding experiments have consistently shown quantum mechanics to be an explicitly nonlocal theory—the outcome Einstein was most averse to accept. However, long-distance relativistic experiments, such as between orbiting satellites, have been technologically cost-prohibitive to date. The paper will be presented at the 2008 IAC Microgravity Sciences and Processes Symposium, under a proposed joint initiative between the European Space Agency and the International Space Station.

"Testing quantum correlations over distances achievable with systems placed in the Earth orbit, or even beyond, would allow to verify both the validity of quantum physics and the preservation of entanglement over distances impossible to achieve on the ground. Using the large relative velocity of two orbiting satellites, one can perform experiments on entanglement where – due to special relativity – both observers can claim that they have performed the measurement on their system prior to the measurement of the other observer. In such an experiment, it is not possible anymore to think of any local realistic mechanisms that potentially influence one measurement outcome according to the other one."

Zeilinger's group has previously conducted proof-of-principle experiments in the Canary Islands with a 144 km free-space link, using an ESA receiver telescope to receive single entangled photons, cf. Nature Physics, 3:481-486 (2007). A more recent experiment in Italy has demonstrated single-photon downlink communications viability from a near-earth orbit satellite, cf. New Journal of Physics, 10:033038 (2008).

The Reality Tests Vienna In Seed (June 2008), the Vienna experimental group discusses physical and philosophical implications of new correlations between entangled photons, which violate an inequality proposed by Leggett for nonlocal realistic theories. This new series of experiments invalidates macrorealism in quantum mechanics by more than 80 orders of magnitude. Preliminary coverage of the experimental results was first presented in Nature 446 (871) and PhysicsWorld, 20 April 2007. According to Časlav Brukner: "Quantum mechanics does not always wash itself out – but to observe its effects for larger and larger objects, we would need more and more accurate measurement devices. We just do not have the sensitivity to observe the quantum effects around us. In essence, we do create the classical world we perceive. There could be other classical worlds completely different from ours."





Quantum networks: Entanglement of distant atoms by projective measurement University of Barcelona | ICFO | Spain Quantum cryptography is rapidly developing into a mature and robust technology for secure data transactions in financial, government and military sector applications. In arXiv 0806.1052, Zippilli et al. quantify the role of photon detector efficiency in quantum repeaters, which will be necessary to scale beyond the point-to-point networks currently employed for secure communications.

Presently, state-of-the-art systems employ atom-photon interaction to generate entanglement between distant nodes across a quantum network through projective measurement. "We assess proposals for entangling two distant atoms by measurement of emitted photons, analyzing how their performance depends on the photon detection efficiency – we believe that these concepts are generally applicable to all systems that may be considered for the creation of distant entanglement, including atomic-ensemble, photonic, and solid state implementations."

The groups's objectives are to quantify the importance of detector efficiency as applied to generating remote entanglement across quantum networks. With minor modifications, these results can be extended to the efficiency of quantum teleportation protocols that are also based on projective quantum measurement. "In all such systems, the detection efficiency will have a similar, important role for the use of the entanglement as a resource in quantum technologies."


Space-QUEST: Experiments with quantum entanglement in space Vienna | ESA | ISS In a recent submission to the arXiv,  Zeilinger's group at University of Vienna, Austria has proposed an experiment – Space-QUEST, Quantum Entanglement Science and Technology – for space-to-ground, entangled-photon Bell Inequality violation measurements to verify quantum nonlocality at distances over thousands of kilometers, in a joint operation between the International Space Station and a ground observatory in the European Union.
 
Entanglement and nonlocality have been pivotal controversies since the birth of quantum mechanics – Einstein's "spooky action at a distance" implies simultaneous, nonlocal correlations between separate entangled particles. J. S. Bell was the first to confirm the phenomenon experimentally in 1964.

Further refinements and increasing precision in succeeding experiments have consistently shown quantum mechanics to be an explicitly nonlocal theory – the outcome Einstein was most averse to accept. However, long-distance relativistic experiments, such as between orbiting satellites, have been technologically cost-prohibitive to date. The paper will be presented at the 2008 IAC Microgravity Sciences and Processes Symposium, under a proposed joint initiative between the European Space Agency and the International Space Station. 
 
"Testing quantum correlations over distances achievable with systems placed in the Earth orbit, or even beyond, would allow to verify both the validity of quantum physics and the preservation of entanglement over distances impossible to achieve on the ground. Using the large relative velocity of two orbiting satellites, one can perform experiments on entanglement where – due to special relativity – both observers can claim that they have performed the measurement on their system prior to the measurement of the other observer. In such an experiment, it is not possible anymore to think of any local realistic mechanisms that potentially influence one measurement outcome according to the other one."

Zeilinger's group has previously conducted proof-of-principle experiments in the Canary Islands with a 144 km free-space link, using an ESA receiver telescope to receive single entangled photons [Nature Physics, 3:481-486 (2007)]. A more recent experiment in Italy has demonstrated single-photon downlink communications viability from a near-earth orbit satellite [New Journal of Physics, 10:033038 (2008)].

Superconducting Qubits RIKEN | UBC | Sherbrooke – In arXiv 0805.0164, Zagoskin and Blais provide a broad and accessible introduction to quantum information processing with superconducting qubits. "From a physicist's standpoint, the most interesting part of quantum computing research may well be the possibility to probe the boundary between the quantum and the classical worlds. The more macroscopic are the structures involved, the better. So far, the most "macroscopic" qubit prototypes that have been studied in the laboratory are certain kinds of superconducting qubits. To get a feeling for how macroscopic these systems can be, the states of flux qubits which are brought in a quantum superposition corresponds to currents composed of as much as 10⁵ - 10⁶ electrons flowing in opposite directions in a superconducting loop."

Efficient pulsed gates for an oscillator stabilized Josephson qubit IBM Watson In arXiv 0709.1478 and New J. Phys. 10 033027 (2008), Koch, DiVincenzo, Brito and Steffen derive operational specifications for high-fidelity one and two-qubit pulsed gates for a superconducting flux qubit, calculating the Hamiltonian with tunable interaction from initialization to readout.

"The quantitative fact that the values of gate infidelity are at the 1% level – and below – is the major result of this paper."

So, can a "debugged" IBM qubit be used soon for universal quantum computation?

"The short answer is, in our opinion, ultimately yes."

"The answer would certainly be no if the noise threshold for fault-tolerant quantum computation were in the neighborhood of the oft-quoted value of 10⁻⁵. It is not inconceivable for the experiment to get to these values someday, since we find that the infidelities decrease much faster than linearly with the assumed noise levels."

"To get to 10⁻⁵, we would need to get to the very daunting levels of 100nΦ₀ at 1Hz for the 1/f noise amplitudes and 100 f s for timing accuracies; there is optimism that both of these numbers are ultimately attainable. Fortunately, while 10⁻⁵ was the threshold as it was understood ten years ago, much recent work shows that with good designs, much higher thresholds are possible. According to Terhal and Burkard – 1% is, in fact, on the high end of the noise levels for which fault tolerance may be possible."

Photon transmission through sub-wavelength diameter apertures Delft | Optica In Optics Express 16, 10 (abstract, full article) and concurrent TU Delft summary, Photonics review, Adam, Planken et al. report on high time-resolution terahertz mapping of photon transmission through sub-wavelength diameter apertures:

"According to the laws of physics, it is particularly difficult to pass light through a hole smaller than half the wavelength of the light used." The Delft group conducted experiments using extremely high time-resolution measurements in the terahertz (THz) frequency range. The group discovered that even if the hole is up to fifty times smaller than the wavelength used, sufficient light can pass through to allow measurements near the hole – an extremely difficult task using other methods. "Improving the sharpness of THz microscopes, coupled with more sensitive detectors, will improve the viability of creating images of biological cells using this type of measurement."

Prior experiments at Leiden University (Nature 418, 304-306) have also studied photon transmission through sub-wavelength metal films and shown entanglement conservation to be much more robust than expected – surviving the conversion process from surface-plasmon waves, which tunnel through the barrier, before reradiating as photons on the opposite side of the film. "It's a good omen, because it's saying quantum entanglement can survive when you might not expect it to," says Bill Barnes, a photonics expert at the University of Exeter. "If they can survive this, what else can they survive?"

Time Reversal in Bose-Einstein Condensates Toulouse | CNRS In arXiv 0804.3514, Martin, Georgeot, and Shepelyansky of Quantware MIPS Center investigate time reversibility in Bose-Einstein condensates (BEC). "We show that inside the regime of quantum chaos, time-reversal dynamics can be inverted from explosion to collapse. The accuracy of time reversal decreases with the increase of atom interactions inside BEC, until it is completely lost – though, surprisingly, quantum chaos helps to restore time reversibility. Existing experimental setups similar to Ryu, Behinaein, and Wayper can test the fundamental question of BEC time reversal discussed here."

DARPA INFOSEC Mandate DARPA | EOP | Congress In Wired briefing 01 May 2008, Danger Room reports on the new DARPA Information Security program mandated by Congress and ratified by the President. The UNISCA First Committee INFOSEC Chair briefing to the UN General Assembly is particularly àpropos to the initiative. "The Defense Advanced Research Projects Agency, or DARPA, was created 50 years ago in response to the Soviets' launch of Sputnik. In less than a year, DARPA put together the infrastructure that guided the American space effort for decades to come. Now, DARPA has been given new marching orders: to help America fight and win battles online.

Under a directive signed by the President – and recently approved by Congress – nearly every arm of the government's security apparatus is starting work on a massive national cybersecurity initiative designed to protect the United States from electronic attack and strike at adversaries online. DARPA's role: to create a cyberwarfare range where all these new forms of electronic combat can be tried out. According to a defense official familiar with the program, "Congress has given DARPA a direct order; that's only happened once before – with the Sputnik program in the '50s."

Danger Room's sister blog, Threat Level, has a good writeup of the cybersecurity initiative, which has been labeled as a Manhattan Project-type effort. In the case of cybersecurity, there is at least talk of big money: about $30 billion dollars. For its part, DARPA's "National Cyber Range" would create a virtual environment where the Defense Department can mock real warfare, both defense and offense.

DARPA today issued an announcement, describing how the range would be a test where the government could conduct unbiased, quantitative and qualitative assessment of information assurance and survivability tools in a representative network environment ; replicate complex, large-scale, heterogeneous networks and users in current and future Department of Defense (DoD) weapon systems and operations ; enable multiple, independent, simultaneous experiments on the same infrastructure ; enable realistic testing of Internet/Global-Information-Grid (GIG) scale research ; develop and deploy revolutionary cyber testing capabilities, and enable the use of the scientific method for rigorous cyber testing.

This is clearly a serious deal for the agency: DARPA Director Tony Tether is a scheduled speaker at the proposers' day workshop scheduled for mid-May, and apparently plans to help handpick the contractors. Tether is known for his close involvement in DARPA contracts. Many of the details surrounding this program will be classified."

Quantum sensor effect in bird navigation? Institute for Electronic Structure and Lasers, Foundation for Research and Technology, Heraklion | University of Crete In arXiv:0804.2646, arXivblog, and Slashdot reports, Kominis investigates the potential for Zeno effect-based quantum sensing in bird navigation. "How birds use the Earth's magnetic field to navigate has puzzled researchers for decades. In recent years, a growing body of evidence has pointed to the possibility that a weak magnetic field can influence the outcome of a certain type of chemical reaction involving the recombination of pairs of ions in bird retinas. The trouble is that the ion recombination is known to happen too quickly for the Earth's weak magnetic field to have any effect. Now it looks as if the quantum Zeno effect may explain the process (abstract). This is the "watched-pot-never-boils" effect, in which the act of observing a quantum system maintains it for longer than expected. This is extraordinary news, because it means a quantum sensor is determining the macroscopic behavior of living birds. Kominis says we may well see these effects elsewhere, and mentions that a similar mechanism might be at work in photosynthesis."

MagiQ Research Labs Andrew Hammond | MagiQ Technologies MagiQ Technologies (NYC) has founded MagiQ Research Labs in Somerville, MA. The lab will provide a technical, engineering and production facility base for public and private sectors in medical optics, quantum information, fiber sensing, aerospace and defense applications, and has been established under research grants from ARO, DARPA, and NASA.

Room-temperature quantum oscillations in diamond crystals UCSB|CNSI|Kavli TU Delft|Ames DOE In Science Express, Science and concurrent UCSB press release, Hanson, Awschalom et al. report on striking experimental observations of quantum oscillations in diamond crystals at room temperature. "We were stunned by these unexpected experimental results, and extremely excited by the ability to control and monitor single quantum states, especially at room temperature," said David Awshalom. "To our surprise, when looking at longer times, the oscillations disappeared, then re-appeared. At first it looked like an artifact, but repeated measurements reproduced this behavior," said co-author Ronald Hanson, a postdoctoral student at UCSB during this period who is now a professor at Kavli Institute of Nanoscience Delft, Delft University of Technology, in the Netherlands.

Workshop on Neuromorphic Computing DSO As profiled in Wired and BAA SN08-16, DSO is hosting a workshop on neuromorphic adaptive plastic scalable electronics to be held on 04 March, 2008. "Briefly, the vision for the anticipated DARPA SyNAPSE program is to enable electronic neuromorphic machine technology that is scalable to biological levels. As compared to biological systems, today’s intelligent machines are less efficient by a factor of one million to one billion in real world, complex environments. The key to achieving the vision of the SyNAPSE program will be an unprecedented multidisciplinary approach that can coordinate aggressive technology development activities in the following SyNAPSE areas: 1) hardware; 2) architecture; 3) simulation; and 4) environment. Hardware includes neuromorphic electronics with novel, high density, plastic, synaptic components; architecture includes neuromorphic design from microcircuit to complete system; simulation includes large-scale digital simulation of neuromorphic circuits and functional neuromorphic systems; and environment includes virtual training, testing and benchmarking for neuromorphic systems realized in hardware or simulation. "

QuanTalk EU QIST Via the Pontiff, a new web-based initiative supported by the European Union under ERA-Pilot QIST grant, QuanTalk. " The purpose of the project is to provide a central facility for open review and discussion of research in quantum information science worldwide. The heart of the site is the Articles section, wherein we provide three main features, (1) Open scientific discussion of the latest research in quantum information. The system will be familiar to those who use forum systems or blogs, but it differs in its approach to permanence and accountability. (2) A community review process, open peer review, to which authors may submit their work. This feature is not yet available during the current beta test of quantalk.org. (3) An open archive where authors can deposit digital material that they wish to make available to the community. During the beta phase, hosting is restricted to PDF documents."

Marc Feldman, 1945-2007 Rochester Marc J. Feldman, professor and scientist in the Department of Electrical and Computer Engineering at the University of Rochester, passed away December 4, 2007 at age 62. Feldman was a founder and early pioneer in the field of superconducting quantum computing. As leader of the Superconducting Electronics Laboratory at Rochester, he led a number of major projects to explore advanced computing concepts. "Marc will be missed tremendously by all, not only was he an outstanding scientist in his own right but he was a generous and prolific scientific collaborator. His deep love of science, boundless intellectual energy and gentle sense of humor made it truly a privilege and a pleasure to call Marc our colleague and friend." – Mark Bocko

Experimental demonstration of Berry's Phase in a solid-state qubit Zürich|Waterloo|Sherbrooke|Yale In Science, arXiv preprint, and concomitant ETH-Zürich report "Geometry for Quantum Computers," researchers in collaboration with the Quantum Device Lab have demonstrated Berry's phase in solid-state circuit quantum electrodynamics, an approach which is inherently robust against certain types of errors. "Geometric phase has been argued to have potential fault tolerance. We demonstrate the controlled accumulation of geometric phase, Berry's phase, in a superconducting qubit, manipulating the qubit geometrically using microwave radiation, and observe the accumulated phase in an interference experiment. "

Back by popular demand – "Donald Duck" technical thread Biercuk (DARPA MTO) As per request, attached are the original posts from the "Donald Duck" technical thread, which were controversially removed from the D-wave weblog shortly after they were posted in advance of the widely-reported press demo early this year. Geordie has stated that the comments were not taken down – though his comment (#35) apologizing for their initial removal appears in the original thread and in closing below. For those who were following the discussion in the days leading up to the demo, the abrupt disappearance of a technical thread left a memorable impression as to the status of further critical discussion on the weblog. Still notably absent from the debate is any substantive discussion of standard industry benchmarks: quantitative characterization of fidelity, persistence of entanglement in the presence of decoherence, amenability to 1/f noise, Rabi oscillations, Ramsey fringes, Larmor frequency, T₁, T₂ – as well any third-party referee or peer-reviewed technical publication outlining these hardware requirements.

Donald Duck January 22, 2007 – Look, I am not aware of any theory that says that NP complete problems are amenable to any significant speedup on a quantum computer. (Factoring intergers, i.e. Shor’s algorithm, I remind you is somewhat special—it is not NP complete). In this case, you will not be able to compete with conventional computers. Another thing to keep in mind. The press conference method of announcing scientific results doesn’t have a very good track record. In 1989, chemists Stanley Pons and Martin Fleischmann held a press conference to report they had successfully achieved cold fusion with a simple device. In 2002, a group called Clonaid held a press conference to announce they had successfully achieved human cloning. In both cases, the stories were widely reported in the press but were later debunked. How about some good old-fashioned peer review? And so what if you can find the ground state of a 16 spin Ising model. I’m willing to bet that in this particular physical device that quantum coherence has very little if not nothing at all to do with it.

Geordie January 22, 2007 – Donald: (1) One of the most fundamental results of QC theory is that QCs can quadratically speed up unstructured search. I suggest you visit Eddy Farhi’s website at MIT and download and read some papers on AQC, or visit arxiv.org and search for adiabatic quantum computing. Most of the papers on AQCs are about solving NP-complete problems. (2) We’re not announcing scientific results. We’re announcing a technical capability. When we do announce scientific results they will be via the peer review process. (3) I would take that bet in a second, but unless you really are Donald Duck I would have difficulty collecting.

Donald Duck January 22, 2007– (1) That is precisely my point. Quadratic speedup is not good enough to be competitive with current computing technology. (2) + (3) Well, it’s not completely clear, but it sounds like you are claiming the technical capability to perform adiabatic quantum computation. If this is true you need to prove experimentally that what you have is AQC and not some sophisticated form of thermal annealing. This is what I would really like to see.

Geordie January 22, 2007 – Donald: I suppose if a quadratic speed up isn’t good enough, then a constant pre-factor speed-up must be even less useful…damn thanks for pointing that out…now I can go back to using my trusty ole abacus. You should probably email Intel and AMD and let them know. Damn “computers” and their useless pre-factor speed-ups. I understand that presentation of scientific results in Science or Nature is appealing to the expert community, and we do have plans to do this. But our primary objective isn’t publishing science papers, it’s building quantum computers.

Donald Duck January 23, 2007 – Geordie: True, quadratic speedup for general purpose computing would be nice—if the cost is not too outrageous. But that’s not what we are talking about here. AQC may give quadratic speedup for a few select algorithms, e.g. Grover’s search algorithm. There are also problems known to be exponentially hard using AQC. I think its very much still an open question as to how useful AQC is w.r.t. computing in general. Yet I also think that studying this will perhaps tell us something very fundamental about the nature of computing and possibly physical reality. However, I’m not convinced that there is now, or ever will be, a market for AQC. Back to your device. I read somewhere else that your technology works at -269C, i.e. 4K, so I take that to mean a liquid Helium temperatures. Now from what I hear, individual s.c. flux qubits, including yours, have a energy gap E0 of about 10GHz or 0.5K. My guess is that a modest collection of coupled flux qubits as in your ‘processor’ has a minimum energy gap ~2 orders of magnitude smaller than E0. So the temperature is something like 3 orders of magnitude greater that the minimum energy gap. How is AQC possible here? How can you even initialize the system?

Geordie January 23, 2007 – Donald: There are only two reasons why QCs will ever be built: quantum simulation and solving NP-complete problems. Both of these represent enormous markets. We’ve checked. Re. your questions about temperature: these are excellent questions. As a generalization of your question, think about ANY AQC operating on a “hard” (ie exponentially small gap) problem. Is there any physical system whose temperature is smaller than the gap at an anti-crossing of a hard problem? Of course not. All AQCs have the feature you’re describing, not just our approach. At an anticrossing, the temperature is ALWAYS going to be orders of magnitude larger than the gap. That’s why inclusion of a thermal environment is REQUIRED in order to analyze how to operate an “AQC” (although note that at the anticrossings it’s not really adiabatic anymore). In order to see what happens when T>>\Delta take a look at the TAQC (Thermally assisted adiabatic quantum computation) paper in the sidebar. Qualitatively, the effect of the large temperature is to thermalize the two energy levels involved in the anticrossing, reducing the probability of success by 1/2, which is of course completely acceptable.

Uncle Scrooge January 23, 2007 – The unfortunate reality is that this is really just classical SFQ being used for what is effectively analog computation (i.e. system simulation). The fact that only Z coupling is achieveable attests to this. Further, given that nowhere in any of your discussions does DWave ever mention quantum coherence, T2, phase evolution, or superpositions, one is forced to believe, as I said, that this is effectively a classical machine. Frankly, you really shouldn’t call your SQUIDs qubits, as they are no more qubits than are the SQUIDs in SFQ pulse generators. They are two level systems (clockwise and counterclockwise propagating persistent currents), but the quantum nature of said system is never exploited! Indeed, given that all experimental results to date have shown coherence times of order ~10-100ns for Nb trilayer devices, I’d be shocked to learn that Dwave had somehow overcome this technological hurdle ahead of the entire research community. If I’m incorrect, please publish something demonstrating quantum coherence using your “qubits” and prove me wrong. I’d be thrilled with such a response.

Geordie January 23, 2007 – Scrooge: ::sigh:: OK I understand that for some reason you’re desperate to find some reason why what we’re doing can’t possibly be correct, which is fine. I’m familiar with this approach. It goes something like this: I can’t figure out how to do it, therefore you can’t figure out how to do it. Do you want me to point out the basic flaw in this reasoning or can you figure it out all by yourself. As to your specific comments:
There is NO SFQ in this design. Zero. The qubits are compound junction RF squids. The tunneling matrix elements for each qubit can be controlled by varying the flux applied through the CJJs for each qubit. This approach is well-known and is centrally featured in the superconducting AQC papers I’ve linked to here. As I mentioned earlier the Hamiltonian is of the X+Z+ZZ type. Notice the X? As to your comment that I haven’t talked about T2 etc. As you yourself pointed out scientific results belong in peer-reviewed scientific articles, not in a blog whose objective is to reach a broad audience with a message that isn’t completely incomprehensible because it’s buried under jargon. As I said before, our objective is to build quantum computers, not to publish science papers. If the latter supports the former, we’ll publish. If it doesn’t then it’s just a distraction for us.

Uncle Scrooge January 24, 2007 – Geordie, I did not claim that you are using SFQ, I claim that the behavior of your system is akin to classical SFQ. My apologies if the word choice was confusing. My criticism of your approach has nothing to do with me figuring anything out, or an apparent claim that I have been unsuccessful in doing so. I don’t work in superconducting qubits. However, I know the field, and the MANY MANY players as well as the challeges they face. You are claiming to have surpassed them all by more than an order of magnitude in the number of qubits you can control and manipulate. Such a claim warrants a publication, or a detailed press release, or something to suggest that you have actually just ushered in the computing revolution which you are claiming. You may not be in the business of publishing science papers, but you are in applied science. The validity of technical claims in ANY applied science discipline is upheld by scientific scrutiny, generally facilitated by publishing scientific results. Would you prefer a webinar? Fine, but demonstrate the behavior you are claiming transparently for all to see. Further, you shouldn’t fall back on the fact that this is a blog. I have read DWave’s papers on the arxiv and find the same lack of anything quantum coherent in your published results (e.g. cond-mat/0509557, cond-mat/0501085). Dwave and collaborators certainly know how to make quasi-classical superconducting electronics and SQUIDs, but where are the superposition states? the Rabi or Larmor oscillations? anything suggesting that you are operating and controlling a coherent quantum system? I understand the premise of AQC, but again ask this: Can Dwave demonstrate that their simulator/processor can take an input superposition state and output the appropriate answers in superposition? If so, please provide the data and I will be most impressed and GLADLY give you the credit you are due. In stark contrast to your claim, I am not desperate to find some reason why what you’re doing is incorrect. Nothing could be further from the truth, but I do expect reasonable experimental evidence to support your very significant claims.

Geordie January 24, 2007 – Scrooge: Fair enough! While we obviously can’t release everything we’ve learned from the hardware, what we’re planning to submit for publication should clarify (at least) the issue of the role of QM in the operation of the system.

Uncle Scrooge January 24, 2007 – I’m looking forward to those publications, but have a follow-up question. Your statement that said publications will “clarify the role of QM [quantum mechanics] in the operation of the system,” gives me pause. We understand the role of quantum mechanics in quantum computing; does the DWave system exploit QM in the same way? Or are the effects what one might term semi-classical? For example, QM plays a significant role in the operation of the laser, the FET, and classical SFQ logic, but none of these are coherent quantum devices. By this statement I mean they do not preserve and exploit quantum mechanical phase information. Accordingly, they cannot provide the parallelism which leads to exponential speedup in a quantum computer. How would one describe DWave’s system?

Geordie January 24, 2007 – Scrooge: I am not so sure you’re correct when you say that the role of QM in QC is understood. There are of course lots of things that are known, but there is still alot of unexplored territory. The example you brought up about temperature & the role it plays in AQC is a great example. From the theory perspective, adding environments qualitatively changes the behavior of the system. I don’t believe that even this simple point is widely understood. There are lots of things like this where computation and physics are related in non-trivial ways, and where cross-overs between classical and quantum behavior may affect computational scaling in a way that isn’t just either/or. Also just to be clear I don’t believe that the system we’re building is going to exponentially speed up anything. The objective is the quadratic speed up for unstructured search. Chris (and also Scrooge): The way we operate our AQCs is like this (X_i and Z_i are the pauli X and Z matrices for qubit i):

(1) Turn up the tunneling term in the Hamiltonian to its maximum value (H=\sum_i \Delta_i X_i)
(2) Slowly turn the qubit biases and coupler strengths up to their target values (these define the particular problem instance); after this process the Hamiltonian is H=\sum_i (\Delta_i X_i + h_i Z_i) +\sum_{ij} J_ij Z_i Z_j
(3) Slowly turn the tunneling terms off; after this the Hamiltonian is H=\sum_i h_i Z_i +\sum_{ij} J_ij Z_i Z_j
(4) Read out the (binary digital) values of the qubits

OK so the point of this is that the qubits are only read out when they are in classical bit states by design. The readout devices are sensitive magnetometers called DC-squids which sense the direction of the magnetic field threading the qubit and hence it’s bit state. The computational model is explicitly set up so that superposition states are used only during the “annealing” stage; the readouts never fire during this step. Answers are encoded in bit strings. Each bit string corresponds to a particular solution. If the computation succeeds, the bit string returned ({s_i}) will minimize the energy E=\sum_i h_i s_i +\sum_{ij} J_ij s_i s_j. Hope this helps! Also re. the demo. There will be almost zero technical stuff in the demo. The foxus is on describing how one would use the system as an application developer–what it does and how you interact with it. All of the science-type stuff, including details of operation, won’t be part of the demo.

Geordie January 24, 2007 – Hi everybody: As a favor to our non-technical audience, if you have any technical questions about the system, please email me directly at rose@dwavesys.com and I’ll try to help.

Also Donald and Scrooge: Sorry about cutting your posts, please email me directly & we can continue the discussion. I love the feedback, keep it coming!

        

Disruptive Technologies SC07 "The disruptive technologies panel serves as a forum for examining those technologies that may significantly reshape the world of high-performance computing (HPC) in the next five to fifteen years, but which are not common in today's systems. Generally speaking, a disruptive technology is a technological innovation or product that eventually overturns the existing dominant technology or product in the marketplace. Disruptive Technologies showcases these technologies in two panel sessions and in a competitively-selected exhibit showcase." This year's showcase featured quantum computing, optical interconnects, CMOS photonics, carbon nanotube memory, and software for massively-parallel multicore processors. The two panel sessions explored potential for disruptions in each major component of HPC architecture: processors, memory, interconnects, and storage.

Progress in Quantum Computing SC07 Panel discussion and HPCWire summary by DiVincenzo. "Hardware to perform quantum information processing is being developed on many fronts. Representing points of view from academia, government, and industry, this panel will give an indication of how work is progressing on quantum computing devices and systems, and what the theoretical possibilities and limitations are in this quantum arena." Panel members included David DiVincenzo (IBM), Wim Van Dam (UCSB), Mark Heiligman (ODNI), Geordie Rose (∂-wave), and Will Oliver (Lincoln Lab).

Rabi, Ramsey, fidelity, 1/f noise, T₁, T₂ MIT EECS Biercuk (MTO) brings back the "Donald Duck" technical thread calling for further clarification on fidelity, 1/f noise, T₁, T₂ Rabi and Ramsey at the new Vatican. Farhi, Chuang, Shor, and Viola follow-up with the same fundamental questions at Amin and Berkley's MIT talk, covered in further detail by Scott Aaronson at Shtetl-Optimized.

    arXivblog, the physics arXiv weblog.

Qulink Seminar on Fault-Tolerant Quantum Computation NII|QIS This week's Qulink seminar by Keisuke Fujii (Kyoto) outlines a novel entanglement purification protocol for fault-tolerant quantum computation in the presence of errors. " The protocol works with high noise thresholds for the communication channels and local operations, and achieves high fidelity of purified states. [...] We consider an interesting relationship between the entanglement purification and fault-tolerant computation, which provides a tight upper bound on the noise threshold for fault-tolerant computation. "


Everett @ 50 Oxford Videos, photos and weblog are now online from the Everett@50 conference held in Oxford, 19-21 July. " This year sees the 50th anniversary of the publication of Hugh Everett III’s seminal “Relative State Formulation of Quantum Mechanics.” This is an opportune moment for leading advocates and critics to come together and debate the Everett interpretation. Sponsored by FQXi and hosted in the Philosophy Faculty of Oxford University, forty of the world’s top academics will come together for three days on July 19th, 20th, and 21st to see if Everett’s explanation of quantum mechanics has at last come of age. "

Superconducting flux qubits: CNOT gate. Horizontal axis represents control qubit rotation; ordinate of colour figures sets number of CNOT gates executed (a) (b) Control qubit input state preparation, (c) (d) target qubit state after CNOT pulse. Plantenberg et al. Nature, 15 June 2007.

CNOT gate demonstrated in superconducting flux qubits Kavli|Delft In Nature 447, 836-839 and concurrent reviews in HPCwire, Scientific American, TU Delft [1] [2] (in Dutch), Plantenberg et al. demonstrate selective execution of controlled-NOT quantum logic gates in a pair of coupled flux qubits. "Complemented with longer coherence times and optimized detector visibility, the presented gates enable experiments on two-qubit quantum algorithms and solid-state qubit entanglement using the four Bell states. This scheme, combined with controllable coupling, forms an attractive and generic approach to implementation of solid-state quantum computing." Detailed analysis of controlled rotations, experimental data and conditional spectroscopy are available at doi:10.1028/nature05896.

Teleportation of massive particles without shared entanglement Queensland|Canberra arXiv quant-ph 0706.0062. " We propose a method for quantum state transfer from one atom laser beam to another via an intermediate optical field, using Raman incoupling and outcoupling techniques. Our proposal utilises existing experimental technologies to teleport macroscopic matter waves over potentially large distances without shared entanglement. "

Martinis Rescues Schrödinger's Cat UCSB In follow-up to Phys Rev Lett 97, 166805 (2006) , " Undoing a Weak Quantum Measurement of a Solid-State Qubit," New Scientist is reporting on upcoming experimental plans to save Schrödinger's Cat from environmental decoherence.

" We propose an experiment which demonstrates the undoing of a weak continuous measurement of a solid-state qubit, so that any unknown initial state is fully restored. Measurement undoing, or "quantum undemolition," may be interpreted as a kind of quantum eraser, in which the information obtained from the first measurement is erased by the second measurement. The experiment can be realized using charge or superconducting phase qubits."

Reversible weak measurement holds security implications for the integrity of present-day quantum cryptography protocols. " This could be a very profound discovery. Since the birth of quantum theory we have become used to thinking of quantum measurements as creating reality: until things are measured, they don't have an absolute, independent existence. But if some forms of measurement, such as weak measurement, are reversible, then the fundamentals of quantum mechanics go even deeper than we realised. If you create reality with weak quantum measurements, does undoing them erase the reality you created?"

Asian Conference on Quantum Information Science Kyoto, 03-06 Sep 2007 The AQIS07 Meeting will focus on quantum information science and technology. This is a new interdisciplinary field that bridges quantum physics, computer science, mathematics, and computing technologies. AQIS07, following tradition, will consist of invited talks and selected oral communications and posters. Contributions for short communications and posters will be solicited in research areas that relate to quantum information science and technology, both theory and experiments. This includes, but is not limited to: quantum automata, algorithms and complexity, quantum cryptography, quantum information theory, quantum entanglement, non-locality, quantum error correction, decoherence-free subspaces, quantum optics, NMR and solid-state technologies, quantum processor design, quantum programming languages and semantics."

Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems Berkeley Lab In Nature 446, 782-786, Fleming et al. report on coherent electron transfer in photosynthetic complexes. " We have obtained the first direct evidence that remarkably long-lived wavelike electronic quantum coherence plays an important part in energy transfer processes during photosynthesis. This wavelike characteristic can explain the extreme efficiency of the energy transfer, because it enables the system to simultaneously sample all the potential energy pathways and choose the most efficient one. " Covered also in Scientific American, Wired, PhysicsWeb, rose.blog.

Tunneling and green tea J Am Chem Soc 129 (18) pp 5846 - 5854 " Tunneling is a ubiquitous phenomenon in nature. We had a problem understanding how polyphenols work at such low concentrations. This paper gives theoretical credence to a large amount of experimental evidence of polyphenols as in vitro and in vivo antioxidants."

Solid-State Qubits with Tunable Coupling NEC|JST|RIKEN In Science 314, 5804, NEC, JST and RIKEN report on tunable coupling between two flux qubits through mutual inductance with a dc SQUID acting as a nonlinear transformer. " ... the research group devised an original mechanism that employs another qubit in between the two qubits for coupling. The coupling qubit is able to turn on and off the magnetic coupling between the two qubits. Control is achieved simply by inputting a microwave. Moreover, coupling operation has been achieved without shortening the lifetime of each qubit." Critical analysis and discussion at Technology Review, rose.blog, nextquant [1] and [2], Scott Aaronson, and Travis Hime on related experiments at Berkeley.

Refuting Nonlocal Realism In Nature 446 (871 - 875) and concurrent arXiv preprint, Zeilinger et al. refute nonlocal quantum realism in experiments with entangled photon pairs. " We measure previously untested correlations between two entangled photons, and show that these correlations violate an inequality proposed by Leggett for nonlocal realistic theories. Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments – unless certain intuitive features of realism are abandoned. " Via Nature, Scientific American, Quantum Quandaries.

Experimental Realization of Deutsch's Algorithm in a One-Way Quantum Computer Belfast|Vienna In Phys Rev Lett 98, 140501 and concurrent preprint coverage in quant-ph/0611186, PhysOrg, Tame, Zeilinger et al.  report on the first experimental demonstration of an all-optical, one-way implementation of Deutsch's quantum algorithm on a four-qubit cluster state. " Experimental results are in excellent agreement with the theoretical model, therefore demonstrating the successful performance of the algorithm." 

Experimental implementation of Deutsch's algorithm in a cluster-state quantum computer Tame, Zeilinger et al. Phys Rev Letters 98, 140501 (2007) . (a) Experimental setup. An ultraviolet pump-laser performs two passages through a nonlinear crystal aligned to produce entangled photon pairs. (b) Sketch of the cluster-state configuration. (c) and (d) Real and Imaginary plots of the reconstructed experimental density matrix.

New links in quantum information processing [1] nextquant Recent topics include d-Wave, Top 5 Urban Legends in Quantum Computing, Superconducting Quantum Computing: d-Wave replies on NEC, The Awful Truth about Schrödinger’s Cat. [2] Strange Paths on physics, computation, philosophy – electron flow paths, escaping from the end of the universe, the quantum eraser experiment. 

xQIT MIT|RLE The Keck Foundation Center for Extreme Quantum Information Theory has been established at RLE under directive to investigate the fundamental limitations to quantum computing, communications, sensing and control. Seth Lloyd and Jeff Shapiro will lead the initiative.

Entangled Quantum Networks ICFO|ICREA|Max-Planck Institute In Nature Physics advance publication 10.1038/nphys549, Acin et al. draw upon the classical percolation methods of statistical mechanics to optimize entanglement distribution through quantum networks. " We argue that there exists an entanglement phase transition in quantum networks which may be exploited to obtain very efficient protocols. This work opens a new set of problems in quantum information theory, which are related to statistical physics, but pose completely new challenges in these fields [...] The work leads to a novel type of critical phenomenon, an entanglement phase transition that we call entanglement percolation. "





Maximizing entanglement in quantum networks. Each node is connected by a state consisting of two copies of the same two-qubit state. The nodes marked in (a) make the optimal measurement for the one-repeater configuration on pairs of qubits belonging to different connections. (b) A triangular lattice is obtained where the maximally entangled state for each connection is the same as for the two-qubit state. Acin et al., Nature Physics, 25 February 2007.

Entanglement engineering for quantum metrology Innsbruck Entanglement-assisted metrology has previously been demonstrated to enhance measurement sensitivity and improve fidelity in noisy conditions. In a quant-ph update to Nature 443 (316), Roos et al. obtain precision atomic clock measurements in the presence of magnetic field noise by engineering a decoherence-free subspace to enhance coherence times. " We find that entangled states are not only useful for enhancing the signal-to-noise ratio in frequency measurements – a suitably designed pair of atoms also allows clock measurements in the presence of strong technical noise. The applied technique makes explicit use of nonlocality as an entanglement property, and constitutes a new paradigm for designed quantum metrology."

        

Signatures for generalized macroscopic superpositions Queensland In quant-ph 0701204 and Phys. Rev. Lett. 97, Cavalcanti and Reid develop signature detection criteria for macroscopic quantum coherence in situations which are not limited to only two macrosopically distinct measurement outcomes. " The criteria provide a means to distinguish a single macroscopic quantum state from one based on a mixture of several microscopic superpositions of pointer-measurement eigenstates." Calculations are provided for the case of Gaussian-squeezed and spin-entangled states.

∂-wave throws down the gauntlet Vancouver Pending third-party referee, peer review or independent verification, D-Wave's press release has been received with expected enthusiasm in the mainstream press and restrained skepticism in the scientific community. "I'll be a bit of a skeptic until I see what they have done. I'm happy these guys are doing it. But the proof of the pudding is in the eating." – Seth Lloyd

Nondemolition measurement. a) Schematic representation of the qubit excitation pulse (top) and readout pulse (bottom) sequence; b) Probability to detect the oscillator in state h for qubit states; c) Measurement of Rabi oscillations; d) Parameters characterizing measurement errors. Lupascu et al. Nature Physics, 14 January 2007.

Quantum non-demolition measurement of a superconducting two-level system Delft|NTT By minimizing disturbance to the system under investigation, quantum nondemolition measurement (QND) can provide particularly clear signatures of quantum coherence. In Nature Physics and cond-mat 0611505, Lupascu et al. demonstrate nondemolition measurement of superconducting qubits coupled to a nonlinear resonator. "The high correlation between measurement results demonstrates the quantum nondemolition nature of the readout method. The fact that quantum nondemolition measurement is possible for superconducting qubits strengthens the notion that these fabricated mesoscopic systems are to be regarded as fundamental quantum objects. Our results are also relevant for quantum information processing protocols such as state preparation and error correction. " cf. also Kavli Institute announcement in TU Delta (in Dutch).

High-speed linear optics quantum computing using active feed-forward measurement Vienna In Nature 445, 65-69 and concurrent press summary, Zeilinger's group reports experimental demonstration of feedforward error correction via one-way, highly-entangled cluster states in linear optics. "With present technology, the individual computational step can be operated in less than 150 ns using electro-optical modulators. This is an important result for the future development of one-way quantum computers, whose large-scale implementation will depend on advances in the production and detection of the required highly entangled cluster states."



Retrocausal Signaling UW Via the Pontiff – John Cramer recently conducted a UW seminar outlining recent progress on his plans for an experimental test of retrocausal signaling using entangled photon pairs, notwithstanding Eberhard's theorem. The planned experiment draws upon the thesis of Birgit Dopfer (Zeilinger group, Universität Wien), Wheeler-Feynman theory and Cramer's own transactional interpretation. Concurrent press summary and diagram of the setup are available via SF Gate. cf. also Cramer's online summary of the proposed experiment, Jensen gedanken, double-slit and delayed choice quantum eraser experiments (refs: serafino).

Quantum Transport in Carbon Nanotubes » links – Condensed matter physics weblog metadatta appended to links. Recent post topics include the Wolf Prize announcement in spintronics and single-quantum dot nanowire light-emitting diodes.

Proton Tunneling in Molecular Biophysics Rensselaer RPI researchers have employed the SCOREC supercomputing cluster to conduct advanced modeling of protein folding dynamics which incorporates quantum mechanical effects to study the influence of proton tunneling in enzyme catalysis. The group's initial study of intein's role in C-termini protein folding will be used to develop nanoscale switches for applications ranging from drug delivery to novel sensors.

Measurement-based Quantum Computing with Superconducting Charge Qubits RIKEN Wang, You and Nori report on measurement-based preparation of superconducting cluster states. "The measurement of the current of a few parallel Josephson-junction qubits realizes a novel type of quantum-state selector. Using this selector, one can produce various quantum entangled states and also realize a controlled-NOT gate without requiring an exact control of the interqubit interactions. In particular, cluster states for quantum computation could be produced with only single-qubit measurements."

Measuring the Size of a Schrödinger Cat State München "We propose a measure for the "size" of a Schrödinger cat state, i.e. a quantum superposition of two many-body states with macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. This definition gives sensible results for simple, analytically tractable cases and is consistent with a previous definition restricted to Greenberger-Horne-Zeilinger-like states. We apply our measure to the experimentally relevant, nontrivial example of a superconducting three-junction flux qubit put into a superposition of left- and right-circulating supercurrent states and find this Schroedinger cat to be surprisingly small."

Symposium for Hans Mooij Kavli|Delft "We see no fundamental reason why superconducting quantum computers cannot be developed into large-scale systems – though, perhaps before then, other applications will also emerge that are much more interesting ..." On Friday, 20^th October 2006 the Kavli Institute of Nanoscience and Delft University of Technology orchestrated a symposium, "The Best of Nanoscience," for Hans Mooij in honor of his attainment of emeritus professor. A program of special guests including Michael Tinkham, David Auston, David DiVincenzo, Seth Lloyd, Yasunobu Nakamura, Hideaki Takeyanagi, John Clarke, Carlo Beenakker, Paul McEuen, Göran Wendin and many other distinguished visitors convened to celebrate Hans's past accomplishments and to highlight future research milestones, followed by a formal reception in honor of the occasion. cf. links to Quantum Transport party committee, TU Delft announcement, featured interview in ∫ Delft Integraal.

Entanglement Demonstrated in Superconducting Qubits UCSB|IBM In Science 313, 5792 and concurrent PhysicsWeb, Scientific American reviews, Martinis et al. report experimental verification of entanglement between two superconducting qubits. "By using simultaneous measurement and state tomography, we demonstrated entanglement between two solid-state qubits. Single qubit operations and capacitive coupling between two super-conducting phase qubits were used to generate a Bell-type state. Full two-qubit tomography yielded a density matrix showing an entangled state with fidelity up to 87%. Our results demonstrate a high degree of unitary control of the system, indicating that larger implementations are within reach."