IIP News 04

news
INTERNATIONAL
INSTITUTE OF
PHYSICS
Natal,
June 2017
Year II Number 04
IIP HOSTS WORKSHOP ON COLLECTIVE SPIN
TRANSPORT IN ELECTRICAL INSULATORS
Interview with
Rogerio Rosenfeld
Professor Rogerio Rosenfeld visited the IIP
last May to present a colloquium on the
developments in the Dark Energy Survey project
and talked with the IIP news about his career
and the novelties in particle physics.
LIGO presents its third
detection
The Laser Interferometer Gravitational-wave
Observatory (LIGO) detected a third gravitational
wave event, showing that a new window in astronomy
has been firmly opened.

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IIP News - Year II, number 04
IIP hosts workshop on Collective Spin
Transport in Electrical Insulators
From April 24 to May 26 the IIP hosted the
workshop Collective Spin Transport in Electrical
Insulators, when researchers from different
countries gathered to discuss the latest’s
achievements in the fields of spintronics.
“The program of the event was very good,
because it left Mondays and Tuesdays for lectures,
leaving the rest of the days of the week
for creating new collaborations. This is very
important, specially for us in Brazil, who don’t
have much contact with foreign researchers”,
Said Denis Candido, one of the participating
students.
The central topics of the program included
collective spin transport, quantum correlations,
novel quantum heterostructures and
more.
This workshop allowed theoretical and experimentalists
could work together when
approaching the main questions in the field
of Collective Spin Transport in Electrical Insulators
and present new alternatives to the
problems of the area. A particularly good opportunity
to researchers looking for new directions
in their careers.
According to Professor Carlos Egues (University
of Sao Paulo, Brazil), one of the event’s
director, “this was a very productive event.
The impression that I had was that people interacted
more during this program. I started
in a new collaboration with one of directors
during the event and I saw the same happening
with others participants. One year from
now I hope to see papers as a result of the
conference”.
The full record of lectures are available in the IIP
Youtube channel (www.youtube.com/iiptv).
Event director, Professor Carlos Egues (USP)
Professor Riccardo Sturani

June, 2017 3
Interview with Prof. Rogerio Rosenfeld
Researcher from the Sao Paulo State University, Professor Rogerio Rosenfeld is involved in the
Dark Energy Survey project, in search for an answer to what are dark energy and dark matter.
He visited the IIP last April to present a colloquium about this subject and talked with the IIP
news about his career and the work he us up to today.
IIP - Tell us about your career.
RR - I started my career in elementary particles at the
University of Sao Paulo. My master thesis was on particles
called axions, which until today have not been detected,
neither they have been eliminated, which is great (laughs),
since nowadays, many particles are being eliminated. After
USP I went to do my PhD in particle physics at the University
of Chicago.
In Chicago I actually worked on Higgs boson, or more
generally, with the sector of spontaneous symmetry
breaking. The Standard Model (SM) of elementary particles
needs a mechanism that gives mass to the particles. This
mechanism comes from a breaking of the “electroweak”
symmetry and the Higgs boson is a consequence of this.
At that time, there was no information about the Higgs
boson and there was a possibility that the sector, which
breaks the symmetry is a sector that is what we call
strongly coupled. My studies then implied that the Higgs
boson would be very heavy.
IIP - That didn’t happen?
RR - This did not happen. As was the case with many other
theories, my work did not apply to SM physics, because the
Higgs boson discovered in 2012, is not really very heavy.
It has a mass of approximately 123 times the mass of the
proton.
IIP - What was it like to be at CERN when the Higgs boson
was announced?
RR - I was spending a sabbatical, from October 2011 to
October 2012 at CERN. Though I knew there was a great
possibility of having this discovery, it was also a great luck!
The LHC is an extremely complex machine. In 2009, when
it was just starting, there was an explosion of some of the
superconducting magnets. That delayed the program by a
year or two.
I was in doubt where to go. I wanted to be in the place
where the Higgs would be discovered, and there was a
competing experiment, with less energy, in a US laboratory
called Fermilab. It was at an accelerator called Tevatron,
which was also looking for the Higgs boson. So when I
had to make my decision, it was not clear that the LHC
was going to work fine while the Tevatron was running
perfectly. It was not easy.
I must say that my wife was the most important factor
because she said “Fermilab no! I’ve been there. Let’s go
to a different place” (laughs). Everything went well. The
Tevatron closed down in 2011 because it could no longer
compete with the LHC and the Higgs boson discovery was
Photo by Juliano Lima Barreto
Professor Rosenfeld talks to UFRN students at the IIP
really a historical moment.
The announcement came out in July 2012 and it was an
incredible euphoria. In the first place I could not get into
the auditorium where the announcement was made. I got
there around 05:00 in the morning. I think it opens at 10
o’clock – and people was already there. It was summer and
you have summer students, who spend a month at CERN.
The students camped in front of the auditorium. I could not
compete (laughs).
IIP - Besides the Higgs boson, the LHC was designed to
look for other new particles. Could you tell us about
supersymmetry, and why it is searched at the LHC?
RR - What is supersymmetry? It is a symmetry that says
that for every particle of the SM there is a “super-partner”.
One reason, why supersymmetric models are interesting is
that they avoid sensitivity of the theoretical mass of the
Higgs to the details of the model at high energies in a
natural way. Natural means that we can swallow this idea
without big hiccups (laughs).
But anyway, the masses of the superpartners should be of
the order of some teraelectronvolts, a thousand times the
mass of the proton. This is also the range of energy, where
the LHC can discover these particles. Alas, so far they
have not been discovered. This leads to these conceptual
problems of naturalness or fine-tuning. It means that we
have to very carefully adjust the parameters of our theory
to ensure that the mass that we measure today is where
it is, and not at some very large energy scale (like Planck
scale).
IIP - So, can we conclude that supersymmetry will not be
discovered?
RR - No. Supersymmetry is a kind of theory you cannot

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fully eliminate. Why? Because you do not know its scale.
We know that supersymmetry is not an exact symmetry of
nature, it has been broken. So it’s a matter of knowing at
which scale this happens. So far we do not have an answer
to that.
It is possible that supersymmetry can be valid only at the
Planck scale. It is very important for string theory and
we may still find that supersymmetry has relevance at
energies lower than the Planck scale. However, the main
motivation was the solution of this problem of fine-tuning
and, apparently, supersymmetry is not responsible for that.
IIP - Another possible new physics is related to Dark Matter
and Dark Energy. What is the difference between them?
RR - With both dark matter and dark energy our evidence
is mostly astronomical and cosmological. Dark matter
is kind of a normal matter, only it does not interact with
light. It has a normal gravitational effect and this is why
it was detected. About 99% of physicists, including myself,
believe that dark matter is a new type of particle that does
not interact with light and has to be stable or have a very
large half-life time comparable to the age of the Universe
because it has not decayed so far. In the Standard Model
there are no candidates for dark matter and so far we have
no clue what it is.
Dark energy is totally different. First, it is a more diffuse
thing - we do not believe it is a particle. Moreover its
gravitational effects is, in a sense, opposite to that of dark
matter. Dark energy has in fact a repulsive effect. It acts like
an antigravity.
The simplest scenario is the cosmological constant. It
was introduced by Einstein in 1917. He wanted to apply
the theory of gravity, which he developed in 1915 for the
Universe as a whole, but he needed a repulsive force to
keep gravitating matter from collapsing. Back in 1917 it
was believed that our galaxy was the whole Universe, and
the stars had fixed stable positions in it. Einstein realized
that he could introduce a repulsive force through the
cosmological constant.
With the discovery of Hubble’s expansion of the Universe in
1929, there was no longer a need for cosmological constant
because the Universe was not static.
With no cosmological constant the expanding Universe
would resist the collapse, but the rate of the expansion
would be decreasing, as if I throw a thing up, it goes, goes,
Photo by: Luiz Barcelos
Professor Rosenfeld at his book signing event
but the speed is decreasing.
IIP News - Year II, number 04
In 1998 there came a great surprise. It was measured
that the expansion of the Universe is accelerating.
Nobody knew why, but they obviously remembered the
cosmological constant. Currently, dark energy is dominant
in the Universe. Our atoms are only 5% of the Universe
and 25% is dark matter.
IIP - You are involved in the Dark Energy Survey project.
What is it?
RR - As I said, my background is in particle physics and I
continue to work with particle physics, but I’ve always liked
cosmology, and 10-15 years ago I started working with it
from the theoretical side. Besides, I got an opportunity to
participate in an experimental project. I found this to be
super cool. There is a group at the national observatory
in Rio de Janeiro that is participating in this Dark Energy
Survey project from the beginning.
The Dark Energy Survey (DES) itself is a international
project with 300/400 participants around the world, led
by the Fermilab. They started investing in this connection
between particle physics and the Universe.
The idea is to map the Universe. The Sloan Digital Sky
Survey, another Fermilab project, covers 1 million galaxies.
The SDS will covers 300 million.
We use a 600 megapixel digital camera, installed in a 4
meter telescope in Chile. This camera takes pictures of
the sky using five different filters, which is different from
the Sloan. Although DES is much less accurate, it gets 300
times more galaxies.
The idea is that dark energy influences the formation of
the Universe, so if you look at the distribution of galaxies
you may have information about dark energy.
IIP - Besides particles you also worked in econophysics.
What was your experience?
RR - When I was in Chicago, I met some people who
worked with economics and finances. Many physicists
were converting to finance. During my second postdoc
I was starting to get worried about employment, so I
started to read some things.
When I came back to Brazil I found a group that was
studying applications of physics in economics. At that time
it was about dynamical systems applied to economics. In
particular, it was very fashionable to talk about chaos, in
application to economics. Thus I began to interest myself
in mathematical modeling of financial systems.
I ended up losing interest, because in the financial market
in recent years it has become important what they call
high frequency trading. Operations on the stock market
occur at microsecond scales, so people have begun to
work on appropriate algorithms instead of those more
elegant theories. It’s called algorithm trading and I don’t
have more time to do this.
In general, however. I think it’s cool that people we train
in physics also have a possibility to work in, for example,
financial modeling, risk control etc.

June, 2017 5
LIGO presents its third detection
By Riccardo Sturani
IIP Associated Professor
The Laser Interferometer Gravitational-wave Observatory (LIGO) detected
a third gravitational wave event, showing that a new window
in astronomy has been firmly opened. Similarly to the first two detections,
the waves were generated by the inspiral of two black holes
which eventually collided to form a larger black hole.
The newfound black hole, formed by the merger, has a mass about 49
times that of our sun, filling the gap between the masses of the two
merged black holes detected previously by LIGO, with solar masses of
62 (first detection) and 21 (second detection).
LIGO made the first-ever direct observation of gravitational waves in
September 2015 during its first observational run since undergoing major upgrades in a program
called Advanced LIGO. The second detection was made in December 2015. The third detection,
dubbed GW170104 and made on January 4, 2017, is described in a new paper accepted for publication
in the journal Physical Review Letters.
The last detection was the farthest yet, located around 3 billion light-years away from the earth.
This experiment helped us to know more about the population of “solar mass” black holes with 20
times the mass of our sun or more, which have not been observed before LIGO detections.
The detections have been made by the twin LIGO detectors, located in the US, one in Hanford in the
Washington state, and one in Livingston, Louisiana state, and they are run by Caltech and MIT. More
than one thousand researchers are part of the LIGO Scientific collaboration, affiliated to a number of
University and research organizations around the world.
In all three cases of the detections made so far, black holes collisions produced an instantaneous
luminosity in gravitational waves larger than the average electromagnetic luminosity of the entire
Universe.
The most recent observation allows to know partial information about the spin of the black holes, i.e.
about the direction of rotation of the individual black holes composing the binary system.
Black holes may rotate in the same or opposite directions with respect to their orbital motion, and
despite the data do not allow to draw definite conclusions, they indicate that at least one of the two
black holes had its rotation axis aligned in the opposite direction than the orbital rotation axis. The
actual inclination of the rotation axis could not be determined, as information about spin direction
would allow to distinguish the binary system formation channel: if from a pre-existing star binary
system or if black holes formed first and then met each other to form a bound system. The detected
indication for misalignment favours formation of binary system from pre-existing black holes in dense
globular cluster.
Moreover a new test of Einstein’s theory of General Relativity has been performed on this event.
Gravitational waves of different frequencies may travel with different speed, a possibility forbidden
by General Relativistic theories but allowed in many of its extensions, much in the same way as light
when travelling in a medium like glass. LIGO did not find any evidence of such an effect, which would
have been stronger in this event rather than in the previous ones since it happened at a distance
roughly twice larger than the two previous ones.
The work in the LIGO project continues, as data taking are currently ongoing, soon to be in coincidence
with the Italo-French detector VIRGO, and new upgrades on all the detectors are scheduled to start
later in 2017 to prepare the next run which should start around the end of 2018/beginning 2019.

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IIP News - Year II, number 04
New Journal Club on entropic matters
A new series of presentations has been launched at the IIP, gathering the institute researchers and other
members of the local scientific community. The main idea behind this journal-club style event is to discuss
interdisciplinary connections brought by the notion of quantum entanglement. Those include quantum
coherence, locality, black holes and quantum gravity. The “Entropic Connections” journal club started its
activities last March and have already approached some very exciting recent developments in the subject
highlighted by articles in top scientific journals .
According to the IIP researcher, Dr. Fabio Novaes, the idea came up from a conversation between him and
one of the new IIP post-docs who asked if the Institute had already had any journal club.
“We always have seminars and colloquiums, but normally presented by visitors. Based on this I started talking
with some other people here and proposed to have a journal club. The idea is to have presentations about
the latest issues in modern physics, presented in a very accessible way to our scientists”, said Dr. Novaes.
Every two weeks a member of the Institute’s research team will talk about some new subject that he or she
finds interesting to be addressed, discussing it with other members and visitors of the IIP in an open and
informal environment.
IIP welcomes new researchers
A new group of post-doctoral researchers
arrived in the IIP during the last month of
April, and have already plunged into the different
research activities at the Institute. The
new members will be representing the fields
of quantum information and foundations of
quantum mechanics, strongly correlated systems
in condensed matter physics as well as
string theory and high energy physics.
Doctors Diego Pires, Romulo Rougemont,
Jacques Pienaar, Flavia Ramos, Sebastien
Eliens, Giancarlo da Silva and Ashutosh Rai
are collaborating with researchers from the
IIP and other institutions in Brazil and abroad.
“I think that the infrastructure and the modus
operandi of the IIP are completely different
from what those of us who did post-graduation
in Brazil, had experienced before. At
post-graduate level, you won’t find an institute
in the country with the organization
of activities such as that at the IIP”, said Dr.
Pires.
Most of these researchers learned about the
Institute during their previous visits to Natal,
participating in one of the many international
events organized by the IIP.
“I first visited Natal in 2013, during a workshop
held by the IIP. So when I ran across an
add about open positions, posted in an SBF
(Brazilian Physics Society) bulletin, I favored
the offered conditions and applied for the
position”, said Dr. Rougemont.
The IIP regularly opens new post-doctoral positions.
Interested candidates are encouraged
to learn more about it at www.iip.ufrn.br.

Next Schools & Workshops
June, 2017 7
Next Conferences
Workshop Black Holes Across the Scales
July 31 to August 18, 2017
IX Brazilian Meeting on Simulational Physics
(BMSP)
August 21 to 25, 2017
Workshop Out of Equilibrium Dynamics in Soft
and Condensed Matter
August 28 to September 10, 2017
Workshop Finite Systems in Nonequilibrium: From
Quantum Quench to the Formation of Strong
Correlations
September 07 to 30, 2017
Workashop Magnetic Fields in the Universe VI:
From Laboratory and Stars to the Primordial
Structures
October 16 to 20, 2017
Workshop LHC Chapter II: The Run for New Physics
November 06 to 17, 2017
Contact us at press@iip.ufrn.br to receive news about our seminars and colloquia in your email.

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IIP Photo Galery
IIP News - Year II, number 04
IIP events in May
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INSTITUTE OF
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