Astronomy and Physics News - University of...
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The field of metamaterials has produced structures with unprecedented abilities, including flat lenses, invisibility cloaks and even optical "metatronic" devices that can manipulate light in the way elec-tronic circuitry manipulates the flow of electrons. Now, the birthplace of the digital computer, ENI-AC, is using this technology in the rebirth of analog computing. A study by researchers at the University of Pennsylvania, The University of Texas at Austin and University of Sannio in Italy, shows that met-amaterials can be designed to do "photonic calcu-lus" as a light wave goes through them. A light wave, when described in terms of space and time, has a profile in space that can be thought of as a curve on a Cartesian plane. The researchers' theo-retical material can perform a specific mathematical operation on that wave's profile, such as finding its first or second derivative, as the light wave passes through the material. Essentially, shining a light wave on one side of such a material would result in that wave profile's deriva-tive exiting the other side. Metamaterials capable of other calculus operations, such as integration and convolution, could also be produced.
Researchers lay out theory for metamaterials that act as an analog
computer
An enormous sunspot, labeled
AR1944, slipped into view over
the sun's left horizon late on Jan.
1, 2014. The sunspot steadily
moved toward the right, along
with the rotation of the sun, and
now sits almost dead center, as
seen in the image above from
NASA's Solar Dynamics Observa-
tory.
Sunspots are dark areas on the
sun's surface that contain complex
arrangements of strong magnetic
fields that are constantly shifting.
The largest dark spot in this
configuration is approximately
two Earths wide, and the entire
sunspot group is some seven
Earths across.
For comparison, another giant
sunspot, five to six Earths
across, is shown below from
2005. The image was captured by
the European Space Agency and
NASA's Solar and Heliospheric
Observatory.
Sunspots are part of what's
known as active regions,
which also include regions of
the sun's atmosphere, the
corona, hovering above the
sunspots.
Active regions can be the
source of some of the sun's
great explosions: solar flares
that send out giant bursts of
light and radiation due to the
release of magnetic energy,
or coronal ...Read more...
NASA's SDO Sees Giant January Sunspots
Department of Physics—United Arab Emirates University Jan. 11, 2014 Volume 4, Issue 2
Credit: NASA
Viewing and manipulating this type of light wave
"profile" is an everyday occurrence for applications
like image processing, though it is typically done
after the light wave has been converted to electronic
signals in the form of digital information. The re-
searchers' proposed computational ...Read more...
A study by researchers at the University of Pennsylvania, The Univer-
sity of Texas at Austin and University of Sannio in Italy, shows that
metamaterials can be designed to do "photonic calculus" as a light wave
goes through them. A light wave, when described in terms of space and
time, has a profile that can be thought of as a curve on a Cartesian
plane. The researchers' theoretical material can perform a specific
mathematical operation on that wave's profile as the light wave passes
through the material. Working like an analog computer, the theoretical
metamaterial illustrated here produces the derivative of the incoming
wave's profile. Credit: Alexandre Silva, University of Pennsylvania
Weekly news from around the world compiled by Dr. Ilias Fernini
Astronomy and Physics News
Researchers lay out theory for metamaterials that act as an analog computer
1
NASA's SDO Sees Giant January Sunspots
1
Quantum mechanics explains efficiency of photosynthesis
2
CeCoIn5 reveals new secrets about how superconductivity and mag-netism can be related
2
Millisecond Pulsar Discovered In Rare Triple Star System
2
Researchers use sound waves to levitate objects in three dimensions
3
Stopping molecules with a centri-fuge
3
Chandra’s Verdict on the Demise
of a Star: “Death by Black Hole”
3
Kilimanjaro at Night 4
Engineers create light-activated
'curtains'
4
Inside this issue:
Light-gathering macromolecules in plant cells
transfer energy by taking advantage of molec-
ular vibrations whose physical descriptions
have no equivalents in classical physics, ac-
cording to the first unambiguous theoretical
evidence of quantum effects in photosynthe-
sis published today in the journal Nature
Communications.
The majority of light-gathering macromole-
cules are composed of chromophores
(responsible for the color of molecules) at-
tached to proteins, which carry out the first
step of photosynthesis, capturing sunlight and
transferring the associated energy highly effi-
ciently. Previous experiments suggest that
energy is transferred in a wave-like manner,
exploiting quantum phenomena, but crucially,
a non-classical explanation could not be con-
clusively proved as the phenomena identified
could equally be described using classical
physics.
Often, to observe or exploit quantum me-
chanical phenomena systems need to be
cooled to very low temperatures. This howev-
er does not seem to be the case in some bio-
logical systems, which display quantum prop-
erties even at ambient temperatures.
Now, a team at UCL have attempted to iden-
tify features in these biological systems which
can only be predicted by quantum physics,
and for which no classical analogues exist.
We found that the properties of some of the
chromophore vibrations that ..Read more...
tional interactions. “This is a truly remarkable system with three degenerate objects. It has survived three phases of mass transfer and a supernova explo-sion, and yet it remained dynami-cally stable”, says Thomas Tauris, first author of the present study. “Pulsars have previously been found with planets and in recent years a number of peculiar binary pulsars were discovered which seem to require a triple system origin. But this new millisecond
If you’re looking for something truly unique, then check out the cosmic menage aux trois ferreted out by a team of international astronomers using the Green Bank Telescope (GBT). This unusual group located in the constellation of Taurus includes a pulsar which is orbited by a pair of white dwarf stars. It’s the first time researchers have identified a triple star system containing a pulsar and the team has already employed the clock-like precision of the pulsar’s beat to observe the effects of gravita-
pulsar is the first to be detected with two white dwarfs.” This wasn’t just a chance discovery. The observations of 4,200 light year distant J0337+1715 came from an intensive study program involving several of the world’s largest radio telescopes including the GBT, the Arecibo radio tele-scope in Puerto Rico, and AS-TRON’s ...Read more...
Quantum mechanics explains efficiency of photosynthesis
Page 2 Volume 4, I ssue 2
Millisecond Pulsar Discovered In Rare Triple Star System
CeCoIn5 reveals new secrets about how superconductivity and magnetism can be related
Superconducting materials exhibit unex-
pected behaviors when subjected to magnetic
fields or high pressures –discoveries that have
implications for controlling electrons in those
special materials. According to two studies,
one conducted at the Paul Scherrer Institute
in Switzerland with collaborators at Los Ala-
mos National Laboratory and a second at Los
Alamos in collaboration with the Sungkyunk-
wan University in South Korea, the supercon-
ducting material Cerium-Colbalt-Indium5
reveals new secrets about how superconduc-
tivity and magnetism can be related.
Superconductivity and magnetism are nor-
mally seen as rivals – superconducting and
magnetic electrons order themselves in very
An illustration of the triple millisecond pulsar
with its two white dwarf companions. Accord-
ing to the new model, this remarkable system
has survived three phases of mass transfer and
a supernova explosion, and yet it remained
dynamically stable. Credit: Thomas Tauris
Clover leaf. Image: Scott Robinson
different ways. Like spinning tops, electrons
in superconductors form pairs of tops, one
spinning counterclockwise and one spinning
clockwise. Together, these pairs move freely
to conduct electrical current with zero re-
sistance. Magnetic electrons, in contrast, lock
themselves into a rigid arrangement that does
not move. Two papers recently published in
the journal Nature Physics show that elec-
trons in Cerium-Colbalt-Indium5 are both
superconducting and magnetic at the same
time.
In an experiment conducted at the Paul
Scherrer Institute, researchers observed an
entirely new form of ...Read more...
Simon Gerber, first author of the publication on the
superconducting properties of CeCoIn5 at the Morpheus
instrument of the Spallation Neutron Source SINQ in
Switzerland. Credit: Paul Scherrer Institute/Markus
Fischer
Researchers use sound waves to levitate objects in three dimensions
A trio of researchers with the
University of Tokyo in Japan has
expanded the science of sound
wave levitation by adding more
speakers and controlling the focal
point of the waves that are creat-
ed. In so doing, as they describe in
their paper they've uploaded to the
preprint server arXiv, they have
created a means for levitating and
moving objects in three dimen-
sional space.
Scientists have come up with sev-
eral ways to levitate objects—
using compressed air, or magnet-
ics, are just two examples—most
such efforts have left a lot to be
desired, however, when the goal
has been clean (no noise, simple
ways to move an object, etc.) levi-
tation. That has led researches to
investigate using ultrasonic waves.
Up till now, researchers have been
able to use the energy of sound
waves to push an object from a
surface up into the air, and then to
hold it there. Because the object
isn't moved in any other direction,
this type of levitation is considered
two dimensional. In this new ef-
fort, the research team has taken
the idea further by adding more
speakers and a control mecha-
nism that allows for moving
the focal point of the sound
waves generated. Objects are cap-
tured in the focal point and are
then moved around by caus-
ing the focal point to be
moved.
In their experiments, the
researchers first levitated
and moved around very tiny
Styrofoam balls. They
demonstrated an ability to
move the balls at will in
virtually any direction—in
tandem. Subsequent tests re-
vealed that their apparatus was
capable of levitating and moving
tiny electric parts, a piece of
wood and a metal nut. The nut
was perhaps most impressive as
it represented a ...Read more...
molecules is the deceleration of molecular
beams. This has been achieved so far only in
the pulsed mode, with a very low duty cycle.
Thus the hitherto-implemented techniques
cannot make use of the intrinsically high flux
delivered by the available continuous molecular
sources. To utilize the full potential of such
sources, a continuous deceleration is warranted.
Towards this end, a team of scientists in the
Quantum Dynamics Division of Professor Ger-
hard Rempe at the Max-Planck-Institute of
Quantum Optics has now developed a versa-
tile deceleration technique ...Read more...
Does the electron possess an electric dipole
moment? Will it be possible to achieve per-
fect control over chemical reactions between
polyatomic molecules, or can one envisage
quantum simulations and quantum compu-
tation with cold polar molecules? The fast-
growing investigation of cold polar mole-
cules holds promise for delivering answers
to these long-standing questions that con-
cern fundamental physics as well as future
applications. Producing abundant samples of
cold polyatomic molecules from thermal
ensembles, however, is a formidable chal-
lenge. A key method for obtaining cold
hole at the heart of a dwarf galaxy
“in the act”.
The results span observations
carried out by the space-based
Chandra X-ray observatory over a
period spanning 1999 to 2005. The
search is part of an archival study
of observations, and revealed no
further outbursts after 2005.
“We can’t see the star being torn
apart by the black hole, but we can
track what happens to the star’s
remains,” said University of Ala-
bama’s Peter Maksym in a re-
cent press release. A comparison
of with similar events seen in larg-
This week, astronomers an-
nounced the detection of a rare
event, a star being torn to shreds
by a massive black hole in the
heart of a distant dwarf galaxy.
The evidence was presented
Wednesday January 8th at the
ongoing 223rd meeting of the
American Astronomical Society
being held this week in Washing-
ton D.C.
Although other instances of the
death of stars at the hands of black
holes have been witnessed before,
Chandra may have been the first
to document an intermediate black
er galaxies backs up the ruling of
“death by black hole.” A compet-
ing team led by Davide Donato also
looked at archival data from Chan-
dra and the Extreme Ultraviolet
Explorer (EUVE), along with sup-
plementary observations from the
Canada-France-Hawaii Telescope
to determine the brightness of the
host galaxy, and gained similar
results.
The dwarf galaxy in the Abell 1795
cluster that was observed has the
name WINGS J134849.88+
263557.5, or WINGS J1348 for
short. The Abell ...Read more...
Page 3 Volume 4, I ssue 2
Stopping molecules with a centrifuge
Fig. left: Photo of the 'centrifuge' / Fig. right: On a fast
rotating disc, an electric quadrupole guide forces the molecules
to move towards the rotation axis. As the molecules have to
fight against the centrifugal force on their way, they lose
kinetic energy and are slowed down to almost a complete
halt. Credit: MPQ, Quantum Dynamics Division.
Chandra’s Verdict on the Demise of a Star: “Death by Black Hole”
(left) Levitation and manipulation of particles. (right) Scooping up and holding particles. Credit: arXiv:1312.4006 [physics.class-ph]
A composite x-ray and optical image of a dwarf
galaxy showing the x-ray transcient in the inset.
Credit-CFHT (Optical), NASA/CXC/
University of Alabama/GSCF/UMD/W.P.
Maksym, D.Donato et al.
College of Science - United Arab Emirates University
POB 15551
Al-Ain
United Arab Emirates
http://fos.uaeu.ac.ae/department/physics
nal Nature Communications. They were able to tweak the size and chirality – referring to the left or right direction of twist – of the nanotubes to make the material react to dif-ferent wavelengths of light. The swaths of material they created, dubbed "smart cur-tains," could bend or straighten in response to the flick of a light switch.
"We envision these in future smart, energy-efficient buildings," said Javey. "Curtains made of this material could automatically open or close during the day."
Other potential applications include light-driven motors and robotics that move toward or away from light, the researchers said. Read more….
Forget remote-controlled curtains. A new development by researchers at the Universi-ty of California, Berkeley, could lead to curtains and other materials that move in response to light, no batteries needed.
A research team led by Ali Javey, associate professor of electrical engineering and com-puter sciences, layered carbon nanotubes – atom-thick rolls of carbon – onto a plastic polycarbonate membrane to create a materi-al that moves quickly in response to light. Within fractions of a second, the nanotubes absorb light, convert it into heat and trans-fer the heat to the polycarbonate mem-brane's surface. The plastic expands in re-sponse to the heat, while the nanotube layer does not, causing the two-layered material to bend.
"The advantages of this new class of photo-reactive actuator is that it is very easy to make, and it is very sensitive to low-intensity light," said Javey, who is also a faculty scientist at the Lawrence Berkeley National Lab. "The light from a flashlight is enough to generate a response."
The researchers described their experiments in a paper published this week in the jour-
Engineers create light-activated 'curtains'
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Physics Department
At the break of dawn the southern Milky Way is photographed over Mount Kilimanjaro, as
seen from Amboseli National Park, Kenya. The Great Carina Nebula is the red cloud at
top. Constellation Crux or the Southern Cross appear on the left. On the Earth is the
second peak of Mount Kilimanjaro reaching 5149 m high, known as Mawenzi (meaning
the moon in Swahili). Credit and copyright: Babak A. Tafreshi. Read more...