FEN
OMEN
NEWSLETTER OF THE DEPARTMENT OF PHYSICS
AND NUCLEAR ENGINEERING
Recent publications
Materials Science
Fast-moving glass
Windows are made of liquid silica, where
molecules are moving so slowly that they
seem to be solid to our eyes. Astonishingly
enough, molecules
in glasses also
perform some
kind of fast mo-
tion, whose mi-
croscopic origin is
not known. A generally accepted explana-
tion is that some molecules are sitting in
“holes” where the density is lower than the
average, and thus move faster than most
molecules. Experiments by the Group of
Characterization of Materials have now
shown that this “hole” theory may not be
universal. Their results were published in
Physical Review Letters in Aug 2009.
Meteorology
Emissions model
Photochemical simulations provide essen-
tial information for understanding pollu-
tion processes and making policy decisions,
with the goal of improving air quality. Sara
Ortega and Marta Alarcón, together with
UPC and UB colleagues, have developed a
new emissions model, MNEQA, to be ap-
plied to the specific case of tropospheric
ozone pollutants. Their work was published
in Atmospheric Environment on April 2009.
Photonics
Anomalous dispersion
Light propagation in photonic crystals at
the high energy range is known to display
surprising behaviors, such as an anomalous
group velocity. Muriel Botey, Jordi Mar-
torell and co-workers have observed that
this leads to an enhancement of second-
harmonic generation of light in the pre-
seence of nonlinearities. The work was
published in Optics Express in July 2009.
Chemical physics
Polarizable salts
Molten copper and silver halides, which
exhibit fast ionic conduction before melt-
ing, present some structural properties
different than molten alkali halides, be-
cause of the anionic polarizability. V. Bi-
trián, O. Alcaraz and J. Trullàs have de-
rived the fluctuation-dissipation theorem
for the static dielectric response function of
systems of ions with inducible point di-
poles, and have shown that this function is
determined by spatial correlations of both
charge and dipole-moment density fluctua-
tions. This work was published in the Jour-
nal of Chemical Physics in June 2009.
Quantum Liquids
Excitation spectrum
of dipolar gases
In the recent years, cold gases with long-
range interactions have attracted much
interest. Such gases are highly impurity-
free, can be cooled to form Bose-Einstein
condensates, and their shape is highly con-
trollable. Grigory Astrakharchik and col-
leagues have studied the excitation spec-
trum of two-dimensional gas with repulsive
dipolar interactions at zero temperature. As
the density is increased, the excitation spec-
trum ceases being monotonous and a “ro-
ton” minimum is formed. The work was
published in Physical Review Letters in March
20, 2009.
DEPARTAMENT DE
F
ÍSICA I
E
NGINYERIA
N
UCLEAR
NÚM. 7, TARDOR 2009
UNIVERSITAT POLITÈCNICA DE CATALUNYA
www.fen.upc.edu
NEWS
2009 FEN POSTDOC-
TORAL FELLOWSHIP
AWARDED
The Research Commission of the
Department has awarded financial
support for a postdoctoral fellowship.
The recipient of the grant this year is
Dr. Alistar Ottochian, who will join the
Group of Characterization of Materi-
als to study relaxation processes in
complex liquids.
OPEN POSITIONS
• PhD fellowship in meteorology
(
marta.alarcon@upc.edu
)
• PhD fellowship in nonlinear and
stochastic dynamics
(
jordi.g.ojalvo@upc.edu
)
VISITING SCHOLARS
• Alain Barrat (ISI, Turin, Italy)
• Marvin Girardeau, Univ. Arizona, USA
• Yurii E. Lozovik, Institute of Spec-
troscopy, Troitsk, Russia
• Arturo Martí, Univ. de la República,
Uruguay
• Marco Masia, Univ. di Sassari, Italy
• Mario Natiello, Lund Univ., Sweden
• Reynald Pain, Univ. Paris, France
• Géza Ódor, Hungarian Academy of
Sciences, Hungary.
• Gordon Pipa and Raúl Vicente, Max
Planck Institute, Frankfurt, Germany
• Osvaldo Rosso, Newcastle Univ.,
Australia
• Ekkehard Ullner, Aberdeen Univ., UK
• Alessandro Villa, Univ. Joseph Fourier,
Grenoble, France
• Evgenii Volkov, Lebedev Physical Insti-
tute, Moscow, Russia
• Joachim Wuttke, Jülich For-
schungszentrum, Munich, Germany
Our postdocs
Erell Bonnot, materials scientist
“I joined the Group of Characterization
of Materials to investigate the barocaloric
effect associated with the martensitic
phase transition in Ni-Mn-In magnetic
shape-memory alloys, by means of high-
pressure dilatometer.
The barocaloric effect
is the analogue, in
pressure, of the mag-
netocaloric effect that
has received consider-
able attention in the
recent years owing to
its potential use for environmentally
friendly refrigeration. It is defined as the
isothermal change of entropy or the adia-
batic change of temperature that takes
place when an external pressure is applied
in a given material. This work, done to-
gether with Josep Lluís Tamarit and
Maria del Barrio, is a collaboration with
Lluís Mañosa from the University of Bar-
celona.”
Erell Bonnot obtained her PhD in physics
from the Universitat de Barcelona in 2008 within
the MULTIMAT network. She joined the de-
partment in December of 2008 and is currently
funded by a postdoctoral grant of the UPC.
Simon Campbell, astrophysicist
“My field of research involves the evolu-
tion and nucleosynthesis of low-mass
stars. To do this I use computer codes that
include the necessary
physics to follow their
entire lifetimes. In
particular I focus on
the evolution of an-
cient stars, that
formed soon after the
Big Bang. These stars
were the first to synthesise and release
heavy elements into the universe. This
material then went into the formation of
other stars, planets - and lifeforms such as
us! I also occasionally do some observa-
tions of stars using optical telescopes. I am
lucky to be sharing an office with two
catalan colleagues, Dr. Gloria Sala and
Jordi Casanova, in the historical EUETIB
building. I will be working with Dr. Jordi
Jose and other colleagues of the DFEN-
DFA Astronomy and Astrophysics Group
(GAA) for another two years.”
Simon Campbell obtained his PhD at Monash
Univeristy (Australia). His thesis won the Best
Australian Astronomy PhD Thesis prize in
2007. Before moving to Barcelona he held a
postdoc position at the Institute of Astronomy and
Astrophysics, at the Academia Sinica (ASIAA) in
Taiwan.
Side Note
Noisy rhythm
generation
In higher organisms, circadian
rhythms are generated by a multicel-
lular genetic clock that is entrained
very efficiently to the 24 hour light-
dark cycle. While most studies so far
have been done assuming that the
clock is entrained by a perfectly peri-
odic driving by light, Jordi García-
Ojalvo and colleagues from the Univ.
Barcelona have discovered that the
circadian rhythm shows a resonance-
like phenomenon as a function of the
noise intensity. The work was pub-
lished in the Biophysical Journal in
May 2009, and was awarded the
journal cover here shown.
DEPARTAMENT DE
F
ÍSICA I
E
NGINYERIA
N
UCLEAR
NÚM. 7, TARDOR 2009
UNIVERSITAT POLITÈCNICA DE CATALUNYA
www.fen.upc.edu
NEW MEC RESEARCH
PROJECTS
The Ministerio de Ciencia e Innovación
(MEC) has granted these projects to FEN:
• “Estudio del componente aerobiológico del
material particulado atmosférico en Cata-
lunya y Canarias” (M. Alarcón)
• "Nonlinear and stochastic dynamics in
physical and biophysical systems" (J García-
Ojalvo)
• “Preparación y estudio de las propiedades
físicas bajo confinamiento micro y
nanométrico” (D.O. López)
• “Dos retos para la evolucion estelar mod-
erna: progenitores de supernova y estrellas
AGB” (E. García-Berro)
• “Dynamic properties in liquid phases: mol-
ten salts, ionic solutions and molecular
liquids” (E. Guàrdia)
GRUPS CONSOLIDATS
The Generalitat de Catalunya has recognized
these Grups de Recerca Consolidats at FEN:
• Grup de transicions de fase, polimorfismes i
dinàmica de la metaestabilitat (J.Ll.Tamarit)
• Propietats dinàmiques i no lineals de materi-
als i sistemes fotònics, elèctrics i biològics (J.
Garcia-Ojalvo)
• Grup de recerca en la transmutació de re-
sidus radiactius (GRETER, G. Cortés)
• Nuclear engineering research group (J. Dies)
• Modelització i simulació discreta de sistemes
biològics (D. López)
• Grup d’astronomia i astrofísica (E. García-
Berro)
• Grup de simulació per ordinador en matèria
condensada (E.Guàrdia)
The following Grup de Recerca Emergent has
also been recognized:
• Grup de caracterització física de materials
mesogens i de memòria de forma (J. Salud)
PHD THESES
• Juanjo Fernández. Advisors: Ramon Vilaseca
and Josep Ll. Font. June 11, 2009.
• Alina Hirschmann. FEN advisor: Eduard
Bravo. July 3, 2009.
• Muriel Botey. Advisor: Jordi Martorell, July 24,
2009.
Edited by
Dept de Física i Enginyeria Nuclear
2a planta Edifici B5, Campus Nord UPC
C. Jordi Girona Salgado, 1-3
08034 Barcelona
Tel.93 401 6973, Fax. 93 401 7100