European researchers prepare for fundamental Action
Quantum mechanics is arguably the most successful physical theory in the history of science. It set out to explain the atomic structure of matter and has since led to revolutionary technologies. Despite many successes, however, the debate about the precise formulation of the theory, its range of validity and the quantum-to-classical transition, it is still open. These open problems continue to be the subject of intense theoretical and experimental research, leading to novel and cutting-edge experiments, with the promise of further technological developments. Now, for the first time, a network is to co-ordinate research in this fascinating area of physics.
Within the context of the intergovernmental framework for European collaboration on science and technology (COST), European members of the quantum-foundations community met in Brussels on 11 April for the first meeting of the COST Action, "Fundamental Problems in Quantum Physics". This project is establishing the first network in the world dedicated to quantum mechanics and its fundamental and fascinating problems.
The Action involves the participation of more than 40 scientists from 20 European and neighbouring countries, and will co-ordinate scientific research, meetings, training schools, workshops and conferences within the community over the next four years. During this first meeting, Angelo Bassi of the University of Trieste and Deltef Dürr of Ludwig-Maximilian University, Munich, were elected as chair and deputy-chair of the Action, respectively, and four working groups were established. These reflect the four major research topics involved.
The working group on "Quantum theory without observers" is chaired by Nino Zanghì, of the University of Genoa. As John Bell stated: "The formulations of quantum mechanics that you find in the books involve dividing the world into an observer and an observed, and you are not told where that division comes – on which side of spectacles it comes, for example, or at which end of my optic nerve […] So you have a theory that is fundamentally ambiguous […]" (The Ghost in the Atom, 1986). This is the famous "measurement problem" of quantum mechanics and the aim of research in this area is to resolve the ambiguity by giving a consistent, paradox-free formulation of quantum theory.
"Effective descriptions of complex systems" forms the topic of the second working group, with Irene Burghardt, of the Goethe University, Frankfurt, as chair. One of the fast-growing areas of research in quantum mechanics is the quantum-to-classical transition. The issues at stake are not only conceptual – how the classical world emerges from the underlying quantum dynamics – but also technological. Novel advances in molecular physics, the most fascinating being energy transfer in photosynthetic systems, will depend a great deal on whether these complex systems retain quantum properties or behave classically. The problem is much debated. The general question is to understand how phenomenological laws, like transport equations describing the behaviour of molecular systems, derive from the underlying microscopic dynamics, which is quantum mechanical.
The third working group, "Quantum theory meets relativity", is chaired by Fay Dowker, Imperial College London. The post-Einsteinian world view is that of a four-dimensional universe in which the laws of physics obey the principle of relativity. However, the marriage of relativity and quantum mechanics turns out to be problematic. First, infinities in quantum field theories indicate that they are not the final theories of nature. Second, the Bell inequalities prove the nonlocality of nature, which deepens the tension with relativity. Third, the problem of quantizing gravity has not been fully resolved. Releasing the tension between quantum mechanics and relativity is a major open problem.
Last, Beatrix Hiesmayr of the University of Vienna chairs the working group "From theory to experiments". Recently, the Nobel laureate Anthony Leggett stated: "I’m inclined to put my money on the idea that if you push quantum mechanics hard enough it will break down and something else will take over – something we can’t envisage at the moment" (New Scientist, 2010). The spectrum of research is wide, and ranges from quantum optics, to molecular, atomic and subatomic physics. Experiments that aim to push quantum superpositions towards the macroscopic scale, involving a larger and larger number of particles, are particularly popular. The most famous experiments are diffraction of macromolecules, opto-mechanical interferometers, as well as superconducting-devices. The technological efforts required are enormous – but so, too, are the expected future pay-offs.
• For more information, see www.cost.esf.org/domains_actions/mpns/Actions/mp1006.
Industry meets academia on silicon photomultipliers
On 16–17 February, CERN hosted the first industry/academia matching event on silicon photomultipliers (SiPMs) and related technologies. It was promoted by HEPTech, the technology-transfer network created by CERN and its member states to enhance technology transfer in the high-energy-physics community. The event attracted around 140 participants from academia (67%) and industry (33%), representing 43 public research organizations and 21 companies.
SiPMs represent the state of the art in low-light detection, with single-photon sensitivity and genuine photon-number resolving capability. Their characteristics and costs make them increasingly attractive to particle-physics experiments and for research applications, notably in medical imaging and fluorescence detection in life science. However, turning an SiPM into a real detecting device or instrument requires the development of appropriate front-end electronics and data-acquisition systems, together with the resolution of non-trivial issues related to the integration of a large number of sensors. These developments fall into the domain of particle physics, which has pioneered the use of SiPMs over the past decade. Today, this community has significant expertise and technological know-how that can be beneficial to other fields.
The event, organized over two half-days, aimed to foster an exchange between various stakeholders from industry and academia, as well as to provide an overview of state-of-the-art technologies and define a roadmap towards collaborative R&D for the development of key solutions for SiPMs in different applications. The programme was split into two parts: on the first day, review talks addressed ongoing developments on the sensors and their applications in various domains; on the second day, companies presented their profiles, products and development projects.
The first day started with an overview of SiPM production and readout electronics and their use in high-energy physics experiments. A review of the application of SiPMs in medical imaging followed. In this field, many groups are carrying out an enormous R&D effort, in particular to improve the light-detection efficiency and the timing performance of SiPM-based detection modules. The astroparticle-physics community has also demonstrated an increasing interest in the use of SiPMs, namely for photon detection in future experimental set-ups. Interesting perspectives for the use of SiPMs also exist in life-science imaging, a domain that increasingly needs the excellent timing characteristics of these devices.
The presentation of the industry view on medical imaging highlighted the importance of taking into account market constraints, business prospects and proper intellectual-property management when transferring such technologies to industry. The series of review talks ended with a field report on the technology transfer of an SiPM readout kit, illustrating the transfer potential of technologies and expertise that are available in the particle-physics community.
The second day was reserved for companies to present their product portfolio and research capabilities, as well as their availability to participate in joint R&D programmes with academia. It gave a taste of how industry is actively extending the development of this technology as well as its eagerness to increase business prospects.
An important aspect of the event was the possibility for the different communities to make contact and merge their interests. There were lively discussions around the demonstrations that were set-up by researchers to promote their technologies. There were also opportunities to meet at the various company booths. Sixteen technology fact-sheets were made available on the event’s website, including job offers and CVs, which turned the meeting into a true market place for everyone involved.
A feedback questionnaire that circulated soon after the event showed that the participants were highly appreciative of the organization, venue and structure, reflecting the importance of selecting the speakers in a way that keeps a good balance between their personal visions and the needs of the community they represent. Many participants recognized that carrying out collaborative R&D with industry is crucial for academia to have access and to acquire expertise in this field for its own research purposes.
The participants expressed their strong interest in a follow-up event, with more emphasis on technology-transfer aspects and related services with a view to increasing the effectiveness of collaboration between academia and industry.
• For more details about the HEPTech network, see www.heptech.org, and for the SiPM event, see http://indico.cern.ch/internalPage.py?pageId=0&confId=117424.
Sergei Matinyan celebrates his 80th year
January 2011 marked the 80th birthday of Sergei Matinyan, a prominent Armenian theoretician and outstanding mentor.
Born in Tbilisi, Georgia, Matinyan established the first high-energy physics laboratory there before moving to Armenia in 1970 as deputy to Artem Alikhanian in the Yerevan Physics Institute and head of the theory laboratory. He was instrumental in organizing the Soviet-American workshops on gauge theories held in Yerevan in 1980s. Attended by many major figures, these were essential events at the time of the Iron Curtain.
He has obtained important results, particularly in the asymptotic theory of hadron interactions, ground-states in non-Abelian Yang-Mills theory and chaos in fundamental physical theories. Recent work has been on nanoscience. Under his supervision, some three dozen students have gained PhDs in quantum field theory, phenomenology, grand unification, supersymmetry (supergravity) and statistical mechanics.