• Henri Desportes 1933–2017 • Patrick Fleury 1935–2017 • Sergei Matinyan 1931–2017 • Gary Steigman 1941–2017

Henri Desportes 1933–2017

It is with great sadness that we announce the death of Henri Desportes, at the age of 84, on 24 September in the village of Gif sur Yvette, France. He was the head of the CEA Saclay department STCM until his retirement in the mid 1990s. Since the 1960s he was a pioneer of applied superconductivity and rapidly became an internationally recognised expert in the development of numerous accelerator and detector magnet systems for high-energy physics.

In particular, Desportes contributed to the creation of the first superconducting magnets  for many experimental programmes, including: polarised targets (HERA, installed at CERN and then in Protvino); the 15 foot bubble chamber at Argonne National Laboratory in the US; the magnet of the CERN hybrid spectrometer bubble chamber in 1972; the first thin-walled solenoid, CELLO, in 1978 at DESY; and the solenoid for the ALEPH experiment at LEP in 1986. His early participation in the genesis and design of the large magnets for the CMS and ATLAS detectors for the LHC should also not be forgotten.

Desportes supervised numerous work at Saclay on the development of innovative superconducting magnets with a wide range of scientific, technical and medical applications. He was the main initiator of new techniques using helium indirect cooling, the stabilisation of superconductor by aluminium co-extrusion and externally supported coils. Henri worked on all of these subjects with some of the great names in physics. It is partly thanks to him that Saclay has been involved in most of the magnets for large detectors built in Europe since the early 1970s. For this work he received a prestigious IEEE Council on Superconductivity Award in 2002.

We will remember his courtesy, his humour and his unfailing involvement in these flagship projects that have contributed greatly to physics experiments and to several fundamental discoveries.

• Irina Antoine Da&eumi;l.

Patrick Fleury 1935–2017

Experimental particle physicist Patrick Fleury passed away on 14 September. After graduating from France’s prestigious Ecole Polytechnique, he first encountered particle physics during a traineeship at Berkeley. On his return, he quickly became a prominent figure in the field of bubble chambers. Appointed by Bernard Gregory, he operated the DBC 81 chamber at CERN, which was built at Saclay in collaboration with the Polytechnique and Orsay. He studied the use of deuterium in the chamber, which received beam from the Proton Synchrotron (PS), and led a study group concerning the f0 spin and the “g” meson. He was also in charge of the construction of CERN’s separated M5 beam, a high-quality beam from the PS.

Quite rightly, Fleury always underlined the crucial role played by the Polytechnique and its leading bubble-chamber experts, first and foremost Louis Leprince-Ringuet, in the development of particle physics at CERN, from its inception to the modern day. Due to Bernard Gregory’s involvement at CERN, Fleury effectively ran Polytechnique’s laboratory (LPNHE-X) from 1973 to 1975, before taking on the role officially until 1984, a period that included its move to Palaiseau. On the new site, he and Charles Gregory built up a technical group capable of building large-scale facilities, and established a strong electronics team and an IT team. Fleury also set up the “solar unit” that would later become a major laboratory, the PICM.

Over the years, Fleury played a major and often pioneering role in several fields of physics at IN2P3 with the support of its director, the late Jean Yoccoz (CERN Courier April 2017 p43), as well as in very-large-scale integration (VLSI) and massive computation, founding the Centre de Calcul Vectoriel pour la Recherche in Palaiseau and installing a CRAY supercomputer there. Fleury then steered his laboratory towards the use of electronic detectors and, from 1968 onwards, oversaw their introduction at CERN, working with Arne Lundby’s group (with Pierre Lehmann) and then becoming involved in the physics of the Omega spectrometer, and later in the DELPHI experiment at LEP.

Following his time at the head of LPNHE-X and a stint at Stanford, he led experiments at Saclay’s Saturne accelerator, before deciding to take his career in a different direction, moving towards what would later be known as astroparticle physics, where he contributed to the establishment of major areas of study. Before Stanford, he had already helped found the Fréjus underground laboratory, on the suggestion of André Rousset, before IN2P3 and the CEA took it over.

Above all, Fleury played a fundamental role in the emergence of ground-based gamma-ray astronomy, both in France and internationally, through the ARTEMIS, CAT, CELESTE and HESS projects, as well as in IN2P3’s involvement in NASA’s FERMI gamma-ray satellite. Alongside Eric Paré, he designed CAT, France’s first Cherenkov imaging telescope and a prototype for the international HESS project. From 1992 onwards, Fleury, a true visionary, launched a series of colloquia on gamma-ray astronomy, which ultimately united all the teams working in the field, including those of MAGIC (La Palma) and VERITAS (Arizona), around the Cherenkov Telescope Array observatory.

Finally, as chair of the scientific-evaluation committee of Virgo, he played a key role in IN2P3’s involvement in the field of gravitational waves. The committee’s report was presented in 1990, the result of hard work and many visits to the international laboratories and agencies involved. Its favourable verdict was a deciding factor in the minister Hubert Curien’s approval of the project in France.

Patrick Fleury was an exceptional scientist, a clear-sighted, passionate and visionary project developer with immense intellectual and moral strength and profound humanity, who always strove to support and instil confidence in his colleagues.

• His colleagues and friends.

Sergei-Matinyan 1931–2017

Renowned Armenian theorist Sergei Matinyan died on 8 September in Durham, North Carolina, aged 86. He was noted for founding now well-known scientific centres: the first high-energy theoretical physics laboratory in Georgia, and a broad-coverage theory laboratory in Yerevan.

Born in Tbilisi, Georgia, and graduating from Tbilisi University in 1954, Matinyan started his scientific career at the Institute of Theoretical and Experimental Physics, Moscow, working on helium superfluidity under Lev Landau. His work on K-meson oscillations carried out later in Tbilisi was an essential step in the field. In the 1960s Matinyan studied strong interactions via complex momentum (Regge) theory, and developed the asymptotic theory of interaction of hadrons with nuclei at very high energies.

An essential phase of his career began in 1970 when he moved to Yerevan, Armenia, to become the deputy of Artem Alikhanian, the founder and then director of the Yerevan Physics Institute. There he went on to head the department of theoretical physics and lectured in Yerevan State University on quantum electrodynamics and the weak interactions. Important work around that time, in 1977, was the investigation of the ground state in non-Abelian Yang–Mills theory, where the presence of a gauge field condensate was demonstrated for the first time.

In the 1990s while at Duke University he summarised his research in the monograph Chaos and Gauge Field Theory, 1994, with Biro and Muller. He was elected to the National Academy of Sciences of Armenia in 1990.

Matinyan was an outstanding mentor and was particularly efficient in attracting gifted students. He supervised more than 30 PhD students in Georgia and Armenia, and his seminars were known for their depth in science and democracy of spirit. Matinyan was instrumental in organising the Soviet–US workshops on gauge theories in Yerevan held in 1983 and 1988, attended by a number of major figures. These conferences were essential events under the conditions of the Iron Curtain.

Sergei Matinyan’s outstanding legacy will be remembered by his former students and colleagues.

• Ara Ioannisian.

Gary Steigman 1941–2017

Gary Steigman played a pivotal role in the development of modern cosmology, particularly the application of particle physics and nuclear physics to cosmological questions. He died on 9 April of complications following a fall.

Born on 23 February 1941, Gary grew up in the Bronx, New York. He received his undergraduate degree from the City University of New York in 1961 and his PhD in 1968 from New York University under the supervision of Mal Ruderman. He joined the Institute of Theoretical Astronomy (now the Institute of Astronomy) in Cambridge as a visiting fellow in 1968 and became a research fellow at Caltech in 1970. Gary joined the faculty of Yale University in 1972, leaving Yale for the Bartol Institute at the University of Delaware in 1978 and was then recruited to Ohio State in 1986.

Gary was ubiquitous on the cosmology conference circuit, so much so that he often referred to himself as the “TWA professor of physics”.  Beginning in 1972, Gary spent 23 summers at the Aspen Center for Physics, where he served as a trustee (1978–1983), a member of the Advisory Board (1983–1998), and a long-time organiser of astrophysics workshops. Visitors to Aspen will remember Holly, Gary’s Great Pyrenees dog (pictured) and a fixture on Gary’s travels.

Gary’s contributions to cosmology span nearly half a century, beginning with his 1968 PhD dissertation, in which he showed that matter–antimatter symmetric cosmologies were untenable: the universe must have an excess of baryons over antibaryons.  This work was published in Nature, and Gary followed up with an influential article in the Annual Review of Astronomy and Astrophysics in 1976. While this conclusion seems obvious now, it was certainly not obvious in the late 1960s; at that time a symmetric universe could have been considered more natural. The origin of the observed baryon excess remains undetermined to this day, but Gary’s results subsequently underpinned the research field of baryogenesis.

This work was followed in 1977 by Gary’s influential primordial nucleosynthesis limit on the number of neutrino species, in collaboration with Jim Gunn and David Schramm. At the time this paper was written there were only weak experimental limits on the number of generations in the Standard Model; Gary’s work demonstrated that this number must be less than or equal to seven, a result later confirmed by SLC and LEP measurements of the Z width. This paper represents one of the first attempts to use cosmology to constrain particle physics, an area that blossomed in the 1980s following Gary’s pioneering work.

Gary received first prize in the 1980 Gravity Research Foundation essay competition for his paper with David Schramm exploring a universe dominated by massive neutrinos, one of the earliest proposals for a nonbaryonic universe. Later, Gary’s 1984 paper with Mike Turner and Lawrence Krauss raised the possibility of a cosmological constant to allow for a flat universe.

He went on to pursue his most significant area of research: primordial nucleosynthesis.  Following early work by Peebles and Wagoner, Fowler and Hoyle in the 1960s, an improved understanding of chemical evolution and better observational limits allowed primordial nucleosynthesis to become the first true area of precision cosmology in the 1980s. With long-time collaborators David Schramm, Mike Turner, Keith Olive and Terry Walker, Gary’s work in this field followed two major thrusts: deriving accurate estimates of the baryon density of the universe, and constraining particle properties. A series of major papers in the 1980s and 1990s provided the gold standard for the prediction of the baryon density of the universe, a prediction spectacularly confirmed by later CMB measurements.

More recently, Gary renewed an earlier interest in relic particle abundances. Among his later papers were a series of improved calculations of these abundances, along with new constraints on fractionally charged relic particles and several important papers on dark radiation.

In 1986, Gary came to Ohio State University to develop a research centre in cosmology that spanned both the physics and astronomy departments. His efforts yielded what is today the Ohio State Center for Cosmology and AstroParticle Physics, encompassing almost 30 faculty members in both departments and more than 15 postdocs.

Gary was a collaborator, a mentor and a good friend. He found his true companion in Sueli Viegas, his wife and fellow astronomer. Gary deserves much of the credit for bringing together the fields of cosmology and nuclear/particle physics, an area of work that became enormously productive in the years following Gary’s pioneering efforts.  Gary blazed a trail for others to follow, and he will be missed by all of us.

• Robert Scherrer, John Beacom, Keith Olive, Michael Turner and Terry Walker.