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THE MAGAZINE OF THE EUROPEAN PHYSICAL SOCIETY
Perovskites: a class of materials with 49/3
multiple functionalities and applications 2 018
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CONTENTS
europhysicsnews
par
europhysicsnews
THE MAGAZINE OF THE EUROPEAN PHYSICAL SOCIETY
Perovskites: a class of materials with 49/3
multiple functionalities and applications 2 018
Livoinxgy goenn M aanErdPs :fS uh 5eo0lw ty oteo ga rpestr ophdaorumtc IeeI 107€ per year (VAT not included)European Union countries price:Volume 49 • number 3
Cover picture: © ESA/ATG medialab; Mars: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO.
See p. 15 Living on Mars: how to produce oxygen and fuel to get home.
EPS EDITORIAL
03 Recruiting Associate Members
R. Voss
NEWS
04 Challenge “Experimental Physics for Africa”
m PAGE 10 HIGHLIGHTS
Perovskites
06 Disordered configurations of the Glauber model on two-dimensional networks
Unresolved puzzles in exotic nuclei
07 High-energy ions’ movement affected by silicon crystal periodicity
Shedding new light on angle-selective Huygens’ metasurfaces
Six decades of cosmology
08 Non-stationary noise with memory in Josephson Junctions
Approximate quantum cloning: the new way of eavesdropping in quantum cryptography
09 Rare events in “noisy” networks
A happy marriage between critical phenomena and spintronics
m PAGE 15
FEATURE
Living on Mars
10 Perovskites: a class of materials with multiple functionalities and applications
C. Rossel
15 Living on Mars: how to produce oxygen and fuel to get home
V. Guerra, T. Silva and O. Guaitella
EPS 50 YEARS
22 A series of articles to celebrate the 50 years of EPS
OPINION
m PAGE 22
EPS 50 years Part II 32 Research: too many indices, too much bureaucracy
EPN 49/3 01

EPS EDITORIAL
[EDITORIAL]
Recruiting Associate Members
The EPS is launching a vigorous initiative to increase the number
and raise the profile of its Associate Members
I
n the European Physical Society, we our credibility as partner of the Euro- have been working hard over the recent
know three categories of members: pean Commission and other European Associate months to propose new schemes which
national Member Societies, Associ- institutions. At the same time, it opens Membership introduce the principle of sponsorship
ate Members, and Individual Members. new opportunities to reach out to the is an essential in a more explicit way than this was
In the first category, the EPS today can individual physicist at his or her daily tool to connect the case in the past. Whereas Associate
be proud to federate not less than 42 workplace, in a way that is complemen- our Society to Membership in its present form will
national physical societies. This covers tary to membership in a national society. the European be continued, the new “EPS Prestige
all of Europe, from Portugal to Russia Associate Members can draw sig- research Sponsorship” will allow an Associate
and from Armenia to Iceland, with nificant benefit from their presence on community Member to support, in a visible and
very few exceptions. However, this also the EPS platform – through publica- at the well-publicised manner, the prestig-
means that there is very little potential tions, conferences, and other actions institutional ious prizes awarded by our Divisions
for growth remaining in this category. and events – to build networks and level and Groups. The new “EPS Sponsor-
The situation is different for EPS partnerships, enhance their visibility ship for Societal Challenges” is specif-
Associate Members. According to in the physics community and beyond, ically aimed at supporting actions or
our definition, Associate Members and to showcase strong vision and distinctions in areas such as physics
“represent cutting edge physics re- leadership in research, sustainability, for development, physics education,
search in European research centres and best practices. diversity, and career development of
and industry”. Indeed we have many To make EPS Associate Member- young physicists – notably, of course,
of Europe’s leading national and in- ship more visible and more attractive, the Young Minds Project! We expect
ternational research organizations the Executive Committee and the that these new schemes will be rolled
on board. They form the bulk of our Secretariat, have teamed up under the out, and all details communicated,
Associate Member base today. In con- strong leadership of Luc Bergé and during the coming weeks and months.
trast, there is only a small number of I hope to have convinced you that
leading research universities and in- our revamped Associate Member
dustries. While today we have almost scheme is based on a broad and long-
as many Associate Members as we term vision, and on much greater am-
have Member Societies – the count bitions than just creating new income
presently stands at 40 – the potential for our society. To make it a success,
for growth is, in principle, enormous. it will need – as always – the strong
From an EPS perspective, Associ- support of all EPS stakeholders: Mem-
ate MembeErPsSh suipppo ritss vaarniou se Ssoscieetnal tacitaioln stool to ber Societies, Individual Members,
for the Development of Emerging Countries,
connect ouPrh Sysiocsc Edieuctaytio tno, Y oruengs eReaseracrchhe rcsentres the present Associate Members, Di-
and Equal Opportunities
and research infrastructures at the in- visions and Groups. Whereas printed
EPS Sponsors for Societal
stitutioCnhaalll elnegveesl s, uapnpdor tt oEP tSh dee vinelodpumsternita l MANY LAUREATES and electronic material is of course
research coamndm eudunciattyi.o Thnale a cltaitvtietire sin par- OF THE PRESTIGIOUS EPS AWARDS RECEIVED being developed to promote the new
THE NOBEL PRIZE IN PHYSICS
ticular is underVriseipt wrewswen.etpesd.o rngot only in schemes, nothing can replace the spo-
To promote tomorrow’s Nobel Laureates,
the EPS, but also in many of our Mem- become EPS PRESTIGE SPONSOR b The EPS ken word and personal contacts.
created a flyer
ber Societies. The mutual benefits are Visit www.eps.org And a last word – as soon as our
to promote
numerous: each new Associate Member the Associate new Associate Member policy is im-
enhances the weight of the EPS in repre- Members plemented, I hope that we can turn
sponsorship.
senting the European physics commu- to addressing the next challenge: raise
This document
nity at large, and reinforces the potential is available the number of Individual Members! n
to achieve our goals. This is of particular online at:
www.eps.org/
importance with a view at building our page/ l Rüdiger Voss,
presence in Brussels, and strengthening membership_am EPS President
EPN 49/3 03
europhysicsnews Challenge
2018 • Volume 49 • number 3
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www.europhysicsnews.org Odette Fokapu Bouquet1,2,6, Daniel Hennequin1,
l
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l 1 Association pour la Promotion Scientifique de l’Afrique (APSA)
Science Editor: Ferenc Igloi (HU)
Email: [email protected] l 2 Physique sans Frontie`res committee of the Socie´te´ Française
Executive Editor: David Lee de Physique (SFP)
Email: [email protected] l 3 Cameroon Physical Society
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Email: [email protected] l 4 Universite´ Paris-Sud
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04 EPN 49/3
EvENTS NEWS
b FIG.1: TCHAKOUNTE for his Solar tracker
Presentation
(figure 2). The amount of the prizes is
of the awards
ceremony high enough to enable the laureates
(Yaoundé, 8th to develop and distribute some proto-
December 2017).
types of their instruments and eventu-
Fisrt row, left to
right: Hyacinthe ally create a small enterprise.
TCHAKOUNTE For this first edition of the chal-
(special jury
lenge, 17 projects were submitted,
prize), Kevin
KENTSA ZANA with only two led by women. Due
(first prize),
to the difficulties in bringing par-
Béranger NYNGA
NINI (second ticipants from other countries, it
prize), Ulrich was restricted to Cameroon. In
SIMO DOMGUIA
the future this challenge should be
and Raoul THEPI
SIEWE (third prize). organized every two years: we will
work to open the next edition to
Sustainable cost scientific on the Arduino platform with mak- other countries and encourage girls’
instrumentation ing of a final project evaluated by a participation. We hope to find the
These observations led us to or- local panel, (iii) selection of the best funding through a strong lobbying
ganize this modest but determined three projects. on African firms. n
action to find local solutions to The challenge ended on 8 Decem-
tentatively improve the teaching of ber 2017, with the awards presentation We want to thank
experimental sciences in secondary (figure1). The first prize (1500€) was our sponsors:
level and bachelor level, stimulate given to Kevin KENTSA ZANA for a International: European Physical So-
the development of locally sustain- didactic test bench, the second prize ciety (EPS), UNESCO
able cost-effective instrumentation (1000€) to Béranger NYNGA NINI for France: Fondation Daniel Iagonitzer,
and develop the research in applied his Physicist Lab and the third prize Institut Henri Poincaré (IHP), Société
sciences in Africa. The challenge was (700 €) to Ulrich SIMO DOMGUIA Française de Physique (SFP),
divided into three main stages: (i) se- and Raoul THEPI SIEWE for their Cameroun: Académie des Sciences du
lection of the best ten candidates by special signal generator. A special Cameroun, Société Camerounaise de
an international panel, (ii) training jury prize was given to Hyacinthe Physique, Société Express Union.
EPN 49/2 05
HIGHLIGHTS FROM EUROPEAN jOURNALS
Highlights
from European journals
COMPLEX SYSTEMS NUCLEAR PHYSICS
Disordered configurations Unresolved puzzles
of the Glauber model in exotic nuclei
on two-dimensional networks
A new review highlights the historical developments in
The Glauber model provides a paradigm for modeling ordering our understanding of the nuclear structure of unstable
processes in complex systems. The question that we answer and unbound forms of helium, lithium and beryllium
is: How is the efficiency of the ordering process in the Glauber
model affected if we rewire the links of the two-dimensional
host lattice? Our research reveals that the fraction of disordered
configurations exhibits a nonlinear dependence on the rewiring
probability. In the small-world regime, the Glauber dynamics re-
mains trapped in a metastable configuration that is disordered.
In fact, we have observed a stationary state that consists of two
intertwined domains of similar size, as shown in the figure. For
higher rewiring probabilities, we observe isolated droplets of
spins, which emerge due to poorly connected nodes in the
network. We have also studied what happens to the ordering
process on two-layer networks, in particular comparing out-
comes on a multiplex network and on the corresponding net-
work with random inter-layer connections. We have shown that,
in this case, the properties of the stationary state are strongly
affected by the type of inter-layer connections. n
m Closed points are matter radii extracted from experiments for isotopes of
Helium (diamonds), Lithium (squares), and Beryllium (triangles).
l I. Baĉić, I. Franović and M. Perc,
'Disordered configurations of the Glauber model Research into the origin of elements is still of great interest.
in two-dimensional networks', EPL 120, 68001 (2017) Many unstable atomic nuclei live long enough to be able to
serve as targets for further nuclear reactions—especially in
. A disordered configuration with two domains comprises a multiclustered hot environments like the interior of stars. And some of the
state on the lattice.
research with exotic nuclei is, for instance, related to nuclear
astrophysics. In this review published recently, the author dis-
cusses the structure of unstable and unbound forms of Helium,
Lithium, and Beryllium nuclei that have unusually large neutron
to proton ratios—dubbed ‘exotic’ light nuclei. The author offers
an account of historical milestones in measurements and the
interpretation of results pertaining to these nuclei. The author
also delineates some of the unresolved puzzles concerning the
connection between microscopic structure and the values of
quantities that are observable experimentally-- particularly the
interplay between energies, widths or strengths and microscop-
ic structure. For example, physicists have yet to resolve what
is the occupancy of an orbital, called 2s , in the ground state
1/2
of beryllium-12? Or what is the nature of the unbound ground
state of helium-10? n
l H.T. Fortune,
'Structure of exotic light nuclei: Z = 2, 3, 4', Eur. Phys. J. A 54,
51 (2018)
06 EPN 49/3
FROM EUROPEAN jOURNALS HIGHLIGHTS
CONDENSED MATTER
High-energy ions’ movement
b Transmission
spectra of a
affected by silicon crystal periodicity
metasurface
in dependence
on the incidence
Thinnest-ever silicon
angle of a TM-
crystal enhances ion polarized plane
channelling performance wave.
in particle accelerators.
The thinner the silicon crys- all light in the forward-direction only, and thereby emulate the
tal, the better. Indeed, thinner behaviour of the forward-propagating elementary wavelets
crystals provide better ways known from Huygens’ principle.
to manipulate the trajectories The authors have investigated this effect in dependence on
m Simulated spatial and angular of very high-energy ions in the incidence angle and polarization of incident plane waves for a
distributions for high-energy protons particle accelerators. Further metasurface composed of silicon nanocylinders. They showed that
along a silicon axis.
applications include materi- the resonance overlap can be designed to appear at an arbitrary
als analysis, semiconductor doping and beam transport in large incidence angle. Furthermore, since the metasurface blocks all
particle accelerators. All of these rely on our understanding of light incident at angles other than the design angle, angle-selec-
how positively-charged high-energy particles move through tive functionalities may be implemented as well. These findings
crystals. This process, called ion channelling, is the focus of a open interesting opportunities for the design of advanced wave-
new paper published recently. In this paper, the authors study front-shaping devices and computer-generated holograms. n
how the crystal periodicity affects the motion of ions whose
energy belongs to a 1 to 2 MeV range, as they are transmitted l D. Arslan, K. E. Chong, A. E. Miroshnichenko, D.-Y. Choi,
through very thin crystals on the order of a few hundred nano- D. N. Neshev, T. Pertsch, Y. S. Kivshar and I. Staude,
metres, and how it impacts their angular distribution. What is 'Angle-Selective All-Dielectric Huygens' Metasurfaces',
so interesting about this work is that it relies on an advanced J. Phys. D: Appl. Phys. 50, 434002 (2017)
process of fabricating much thinner crystals than was previously
possible, reaching 55 nanometres. This, in turn, makes it possible
to observe much more sensitive and fine angular structures in
the distribution of transmitted ions. n HISTORY
Six decades of cosmology
l M. Motapothula and M. B. H. Breese
'A study of small impact parameter ion channeling effects The personal memories of Jayant Narlikar point to the need
in thin crystals', Eur. Phys. J. B 91, 49 (2018) for restoring cosmology as the flagship of astronomy.
"Cosmologists are often wrong but never in doubt,” Russian
physicist Lev Landau once said. In the early days, astronomers
began by observing and modelling stars in different stages of
APPLIED PHYSICS evolution and comparing their findings with theoretical predic-
Shedding new light tions. Stellar modelling uses well-tested physics, with concepts
such as hydrostatic equilibrium, law of gravitation, thermo-
on angle-selective
dynamics, nuclear reactions etc. Yet in contrast, cosmology is
Huygens’ metasurfaces based on a large number of untested physical assumptions,
like nonbaryonic dark matter and dark energy whose physics
has no proven link with the rest of physics. In a paper published
Huygens’ metasurfaces form a class of ultra-thin optical devices
. Cosmos
which allow scientists to reshape the wavefront of an incident
beam of light. Representatives of this class include highly effi-
cient flat lenses, beam shapers, and holographic phase masks.
More specifically, such metasurfaces are composed of a carefully
designed, two-dimensional arrangement of high-refractive-in-
dex dielectric nanoparticles, which show virtually no absorp-
tion losses and exhibit electric and magnetic dipole resonances
known from Mie scattering. When these resonances are de-
signed to overlap spectrally, the nanoparticles scatter almost
EPN 49/3 07
HIGHLIGHTS FROM EUROPEAN jOURNALS
recently, the author shares his personal reminiscences of the QUANTUM PHYSICS
evolution of the subject of cosmology over six decades. He tells Approximate quantum cloning:
of the increase in our confidence in the standard model of cos-
the new way of eavesdropping
mology to the extent that it has become a dogma. The German
physicist Max Born said many years ago: "Modern cosmolo- in quantum cryptography
gy has strayed from the sound empirical road to a wilderness
where statements can be made without fear of observational New approximate cloning method avoids the previous
check...”. The author feels that those comments apply very well limitations of quantum cloning to enhance quantum
to the present state of cosmology. n computing and quantum cryptography leaks
l J. V.Narlikar, Cloning of quantum states is used for eavesdropping in
'The evolution of modern cosmology as seen through a quantum cryptography. It also has applications in quantum
personal walk across six decades', Eur. Phys. J. H 43, 43 (2018) computation based on quantum information distribution.
Uncertainty at the quantum scale makes exact cloning of
quantum states impossible. Yet, they may be copied in an
approximate way—with a certain level of probability—using
APPLIED PHYSICS a method called probabilistic quantum cloning, or PQC. In a
Non-stationary noise with memory new study published recently, the authors demonstrate that
partial PQC of a given quantum state secretly chosen from a
in Josephson Junctions
certain set of states, which can be expressed as the superpo-
sition of the other states, is possible. This cloning operation is
very important with regard to classical computing. It allows
scientists to make many copies of the output of computa-
tions—which take the form of unitary operations. These can,
in turn, be used as input and fed into various further processes.
. New approximate cloning method facilitates quantum computing.
© Markus Spiske via Unsplash
m The current flowing across a josephson junction may be thought of as including
a memristive component I due to the microscopic process of pairs breaking,
M
tunneling and recombining across the junction. As this process is dissipative, it
also affects the intrinsic noise of the junction.
In addition to the non-dissipative supercurrent, Josephson junc-
tions also possess a dissipative memristive current component,
meaning that the instantaneous resistance of the junction depends
on the history of the current. Devices that display this exotic behav-
iour are currently under intense study due to possible applications
ranging from fast, high-density, nonvolatile computer memories to
neuromorphic computing. In a previous work, the authors suggest-
ed a novel device to isolate this current component and thus realize
a superconducting memristor. In this work the manifestation of
the memristive behaviour in the current noise is considered. The
presence of memory renders this noise non-stationary. The authors
theoretically characterize both the thermal noise and the 'dynam-
ic'-noise arising across a biased junction, using a mixed time-fre-
quency description. A way to detect this effect of the memristive
behaviour on the current noise is also proposed, which should be
feasible with current experimental tools. n
l F. Sheldon, S. Peotta and M. Di Ventra,
'Phase-dependent noise in Josephson junctions', Eur. Phys.
J. Appl. Phys. 81, 10601 (2018)
08 EPN 49/3