Cardiff researchers could herald a new era in fundamental
physics
Cardiff University researchers who are part of a
British-German team searching the depths of space to study
gravitational waves, may have stumbled on 1 of the most
important discoveries in physics according to an American
physicist
Cardiff University researchers who are part of a British-German
team searching the depths of space to study gravitational waves,
may have stumbled on one of the most important discoveries in
physics according to an American physicist.
Craig Hogan, a physicist at Fermilab Centre for Particle
Astrophysics in Illinois is convinced that he has found proof in
the data of the gravitational wave detector GEO600 of a
holographic Universe – and that his ideas could explain
mysterious noise in the detector data that has not been
explained so far.
The British-German team behind the GEO600, which includes
scientists from the School of Physics and Astronomy's
Gravitational Physics Group, will now carry out new experiments
in the coming months to yield more evidence about Craig Hogan's
assumptions. If proved correct, it could help in the quest to
bring together quantum mechanics and Einstein's theory of
gravity.
In order to test the theory of holographic noise, the frequency
of GEO600´s maximum sensitivity will be shifted towards ever
higher frequencies. The frequency of maximum sensitivity is the
tone that the detector can hear best. It is normally adjusted to
offer the best chance for hearing exploding stars or merging
black holes.
Even if it turns out that the mysterious noise is the same at
high frequencies as at the lower ones, this will not constitute
proof for Hogan's hypothesis. It would, however, provide a
strong motivation for further study. The sensitivity of GEO600
will then be significantly improved by using 'squeezed vacuum'
and by the installation of a mode filter in a new vacuum
chamber. The technology of 'squeezed vacuum' was particularly
refined in Hannover and would be used in a gravitational wave
detector for the first time.
Professor Jim Hough of Glasgow University, one of the pioneer
developers of gravitational wave detectors, says: 'Craig Hogan
made a very interesting prediction. It may be the first of a
number of unexpected possibilities to be investigated as
gravitational wave detectors become more sensitive.'
Professor Bernard Schutz, Professor at the School of Physics and
Astronomy, member of the Gravitational Physics Group at the
School, and recently elected as an Honorary Fellow of the Royal
Astronomical Society said: "It would be truly remarkable if
GEO600 is sensitive to the quantum nature of space and time. The
only way to confirm that would be to carry out controlled
experiments, the results of which can be solely attributed to
holographic noise. Such an experiment would herald a new era in
fundamental physics".
Proffessor Dr. Karsten Danzmann, director of the Hannover
Albert-Einstein-Institute, said: "We are very eager to find out
what we can learn about the possible holographic noise over the
course of the coming year. GEO600 is the only experiment in the
world able to test this controversial theory at this time.
Unlike the other large laser interferometers, GEO600 reacts
particularly sensitively to lateral movement of the beam
splitter because it is constructed using the principle of signal
recycling. Normally this is inconvenient, but we need the signal
recycling to compensate for the shorter arm lengths compared to
other detectors. The holographic noise, however, produces
exactly such a lateral signal and so the disadvantage becomes an
advantage in this case. You could say that this has placed us in
the very centre of a tornado in fundamental research!
Searching for the graininess of space
The smallest possible fraction of distance is called the 'Planck
length" by physicists. Its value is 1.6 x 10-35 m – this is
impossible to measure by itself. The established physical
theories cease to function at this scale. GEO600 scientists are
testing a theory by US physicist Craig Hogan, who is convinced
he can hear the noise of space quanta in the data of the
gravitational wave detector GEO600. Hogan suggests that the
mirrors in an interferometer wander relative to one another in
very rapid steps of the tiny Planck amount, that accumulate
during the time of a measurement into something as large as a
gravitational wave would produce. Hogan and the GEO600
scientists are following up the question whether a certain
'noise signal' in the data recorded by the detector can be
traced back to the graininess of space and time.
GEO600
Because of its innovative and reliable technology, GEO 600 has
gained an excellent worldwide reputation and is considered a
think-tank for international gravitational wave observation. It
was here that the most modern lasers in the world were developed
which are being used in all the gravitational wave observatories
in the world today. Researchers at GEO600 are taking technology
a step further with 'squeezed vacuum'. This technology is
designated for use in the third generation of gravitational wave
detectors. GEO600 is a joint project of scientists of the Max
Planck Institute for Gravitational Physics (Albert Einstein
Institute, or AEI), Leibniz Universität Hannover, Cardiff
University, the University of Glasgow and the University of
Birmingham. It is funded jointly by the Max Planck Society in
Germany and the Science and Technology Facilities Council in UK.
The Centre for Gravitational Physics, Albert Einstein Institute
(AEI) Hannover
At the Centre for Gravitational Physics, the Max Planck Society
and Leibniz Universität Hannover jointly carry out experimental
gravitational wave research. This includes basic research as
well as applied research in the fields of laser physics, vacuum
technology, vibration isolation in addition to classical optics
and quantum optics. Other research focuses on the implementation
of data analysis algorithms for different sources of
gravitational waves. Together with the theoretical departments
of the Max Planck Institute for Gravitational Physics in
Potsdam, the Albert Einstein Institute constitutes a unique
research centre for gravitational physics which covers all
aspects of this field.
Together with British research institutes, the Centre for
Gravitational Physics runs the gravitational wave detector
GEO600 in Ruthe, near Hanover. Scientists of the institute are
also leading participants in LISA (Laser Interferometer Space
Antenna), the planned gravitational wave detector in space. This
joint project by NASA and ESA will measure gravitational waves
in space from 2018 on, and wil thus "listen" into deep space
further than ever possible before.
Cardiff School of Physics and Astronomy
The Cardiff School of Physics and Astronomy has a very active
astrophysics programme with 17 academic staff and more than 100
researchers. It has excellent computational facilities, two
Beowulf clusters and more than 50 TBytes of data storage, and a
world-leading instrumentation lab. The research groups are
involved in a number of key observational projects including
Planck, Quad, Herschel, Clover, SCUBA, and the Square Kilometer
Array.
Direct detection of gravitational waves has been the focus of
research for the Gravitational Physics Group at Cardiff for more
than a decade. The quest for gravitational waves has been the
driving force since the group, jointly with the Universities of
Glasgow and Hanover and the Albert Einstein Institute (Golm and
Hanover), led the proposal to build the British-German GEO 600
interferometer. The group is an integral member of the LIGO
Scientific Collaboration and is involved in all the major
gravitational-wave interferometer projects, LIGO, Virgo, GEO 600
and LISA.
2. Cardiff University
Cardiff University is recognised in independent government
assessments as one of Britain's leading teaching and research
universities and is a member of the Russell Group of the UK's
most research intensive universities. Among its academic staff
are two Nobel Laureates, including the winner of the 2007 Nobel
Prize for Medicine, Professor Sir Martin Evans. Founded by Royal
Charter in 1883, today the University combines impressive modern
facilities and a dynamic approach to teaching and research. The
University's breadth of expertise in research and research-led
teaching encompasses: the humanities; the natural, physical,
health, life and social sciences; engineering and technology;
preparation for a wide range of professions; and a longstanding
commitment to lifelong learning. Visit the University website
at: www.cardiff.ac.uk
Further information of the internet:
Max Planck Institute for Gravitational Physics (Albert Einstein
Institute): http://www.aei.mpg.de
GEO600: http://www.geo600.de
Holographic Universe: C. Hogan, Indeterminacy of holographic
quantum geometry, Phys. Rev. D 78, 087501 (2008).
http://www.newscientist.com/article/mg20126911.300-our-world-may-be-a-giant-hologram.html?full=true
