Interferometric Detection of Gravitational Waves : 5 Needed Breakthroughs -- David Blair

[ After David Shoemaker of LIGO and Jean-Yves Vinet of Virgo, today we present Prof. David Blair's list of 5 breakthroughs that he expects to see in his field of research -- the interferometric detection of gravitational waves -- the topic that we are currently focusing on.

David Blair is Director of the Australian International Gravitational Research Centre (AIGRC) and a Professor of the University of Western Australia, Nedlands. Since late 1980's he is leading the Australian research effort for the detection of gravitational waves.

In the 1980's he built a very sensitive resonant mass detector called NIOBE, consisting of a huge bar of the metal niobium cooled to a few degrees above absolute zero. This detector operated as part of a world wide network which set upper limits on the number of bursts from our galaxy. These results implied that there was no unexpected population of sources such as coalescing black holes in our Milky Way.

In the 1990's Blair with colleagues across Australia proposed setting up an Australian large scale interferometer detector AIGO. Phase 1 of this project has been substantially completed. It is located at Gingin, Western Australia, on a large site set aside for a long baseline detector. The current facility is working to develop the technology for the next stage, an Advanced high optical power interferometer. It uses high power lasers developed by Prof Jesper Munch's group at the University of Adelaide, and control systems developed by LIGO and by Prof David McClelland's group of the Australian National University.

The Gingin facility is a joint facility of the Australian Consortium for Gravitational Astronomy and the LIGO Scientific Collaboration. The main focus of research is on developing control systems for very high power suspended optics in which thermal effects and radiation pressure effects must be carefully controlled. When the Australian detector is developed into a full scale observatory it will contribute a large improvement to the angular resolution of the world wide network, and enable signals to be identified with distant host galaxies - roughly a 16 fold increase in the number of potential host galaxies.

He also plays an important role in the activities of the Gravity Discovery Centre, the associated award winning public education centre on the AIGO site. It's an inspirational self supporting, non-profit public education and tourism centre that focusses on the big questions of Life and the Universe, and the extraordinary biodiversity of Wallingup Plain.
- 2Physics.com Team ]

"1.First detection of a single event to prove the viability of gravitational wave detection and the existence of detectable waves.

2. Demonstration of high optical power interferometry to pave the way for advanced detectors.

3. Operation of advanced detectors and the detection of frequent GW signals.

4.Operation of detectors with sensitivity better than the standard quantum limit.

5. Detection of cosmological gravitational waves from the big bang and tests of the theory of inflation. "

Relevant Links:     AIGRC     Gravity Discovery Centre     LIGO Science Colloaboration

Interferometric Detection of Gravitational Waves : 5 Needed Breakthroughs -- Jean-Yves Vinet

[We are continuing our feature on '5-Breakthroughs' -- this time with inputs from Prof. Jean-Yves Vinet ....

Jean-Yves Vinet was involved in the French-Italian Virgo project for the detection of gravitational waves since the very beginning (Year 1984!) as a collaborator of Alain Brillet, who, with A. Giazotto, promoted the idea of the Virgo project.

Regarding terrestrial instruments like Virgo or LIGO, his interest lies mainly in the theory of the instrument itself (optics, thermal noise, R&D for advanced instruments...). He is also involved in NASA's proposed space-based detector LISA where again he finds his interest in the instrument itself (transfer function, low frequency regime, time delay interferometry...) and also the data Analysis issues.
Jean-Yves is currently a "Directeur de Recherche" at C.N.R.S, France. He is a member of the LISA International Science Team and also of the Fundamental Physics committee of the Centre National d'Etudes Spatiales (the French space agency). He was a professor at Ecole Nationale de Techniques Avancées (Paris) (Laser Physics, 1991-99) and then a searcher at Département d'Astrophysique Relativiste (Observatoire de Paris-Meudon) (1999) and thereafter a searcher at Artemis (Observatoire de la Côte d'Azur, Nice, France) since 2000.

He teaches a master's course on Experimental Gravitation at Université de Nice-Sophia-Antipolis.
-- 2Physics.com Team]

"In my opinion, important breakthroughs would be for instance:

1) Find an optical design matched to light beams homogeneously distributed on the mirror surfaces in order to reduce the spurious thermal effects, the thermal noise and the thermodynamical noise.

2) Then find a laser able to produce such beams (fiber laser).

3) Adopt the continuous detection scheme (no modulation).

4) Organize a full cooperation among existing antennas (this seems to be on the way).

5) Get more funding for R&D (Europe!)"

Relevant links:     Virgo Project     LISA

"Interferometric Detection of Gravitational Waves : 4 Needed Breakthroughs" -- David Shoemaker

David Shoemaker standing next to the full-scale interferometer testbed in LIGO MIT Lab (photo courtsey: LIGO MIT Laboratory)

[We asked leading scientists of various fields to point out 5 needed breakthroughs that they would like to see in their own field of research. We are starting this feature today with the input from Dr. David Shoemaker.

David Shoemaker played an important role in both the R&D effort and commissioning of the joint Caltech-MIT LIGO laboratory for the detection of gravitational waves. Currently, he is Director of the LIGO MIT Laboratory at Kavli Institute for Astrophysics and Space Research, MIT. He also leads the LIGO research group on Advanced LIGO Development.
-- 2Physics.com team]

"Four, rather than five, breakthroughs would satisfy me:

- A means to significantly reduce (through changes in formulation or process) or circumvent (via an alternative optical topology) the thermal noise in the reflective dielectric coating on the test masses (and in the bulk of the test masses as the next step!)

- Successful application of prepared states of light to improve the sensitivity of full-scale gravitational-wave detectors while keeping circulating power at technically acceptable levels.

- A practical application of a method to regress out (via e.g., an array of seismometers) or reduce (via e.g., a mechanical design) the gravitational gradient noise, allowing lower frequency operation on the ground.

- ....and, slightly different in character: The first direct detection of a gravitational wave."

Relevant Links:
LIGO Laboratory     LIGO MIT Laboratory    LIGO Science Collaboration

"Existence of Axion" -- R.N. Mohapatra

Rabindra N. Mohapatra (photo courtsey: U. of Maryland)

[This is an invited article. In a recent publication in Physical Review Letters, R.N. Mohapatra (U. of Maryland) and Salah Nasri (U. of Florida) have put forward a theory that can reconcile conflicting results from two experiments that tried to test the existence of "axion" -- an ultralight particle that could make up dark matter. We thank Prof. Mohapatra for contributing this article on our request. -- 2Physics.com Team]

Axions were proposed by Roberto Peccei and Helen Quinn as a way to solve one of the fundamental mysteries of nuclear forces i.e. an inordinately large amount of CP violation in the otherwise successful theory of these forces, Quantum Chromodynamics (QCD) proposed by D. Gross, F. Wilczek and H. D. Politzer. Since their debut into the world of theoretical physics, axions have also been found useful in another context: being ultralight particles (believed to be a billion times or more lighter than the electron) they are capable of populating the Universe so abundantly that they could be candidates for the dark matter of the Universe and thereby resolve another fundamental mystery of cosmology.

Salah Nasri (photo courtsey: U. of Florida)

Because of these twin attributes (solving the problem of QCD and being a candidate for dark matter), considerable amount of research is being devoted to establishing the existence of axions. One of their key properties is that they couple to two photons (one being the magnetic and the other the electric component of light). Therefore interaction of laser beams with strong magnetic fields is considered to be an efficient way to search for them[1].

Two recent attempts that use this technique to search for axions are the CERN CAST (CERN Axion Solar Telescope) experiment[2] and PVLAS experiment at INFN-LNL[3]. The CAST experiment searched for axions produced by light-by-light collision at the center of the Sun and gave a negative result setting strong limits on the axion-photon coupling and its mass. The PVLAS experiment on the other hand looked for axions produced by laser-magnetic field interaction in the laboratory and seems to have a positive evidence for an axion like particle. Their observations can be understood only if the axion-photon coupling are considerably larger than the upper limits set by the CAST result. This has posed a major challenge for theory and in the very least implies that the axion solution to the problems of QCD may be much more complex than previously envisioned or the PVLAS experiment could be the result of completely new kind of phenomenon, not related to the axion.

In a recent Phys. Rev. Lett. Paper [4], we have proposed a new way to reconcile the CAST and the PVLAS results. We use the axion possibility in our approach except the theory has several new features compared to the conventional axion models. We use the phenomenon of phase transition so well known in the study of condensed matter physics (e.g. loss of magnetism of ferromagnets at high temperature). Our basic observation is that the axion photon coupling is not a primordial coupling but is induced by the formation of a vacuum condensate. Therefore the strength of the coupling depends on the environment temperature.

Note that the solar axions are produced at a very high temperature of about 10 million degrees in the core of the Sun whereas the PVLAS axions are produced at room temperature. Therefore if the vacuum condensate responsible for axion-photon coupling undergoes phase transition to zero value in the solar core due to its high temperature, there would be no axion production in the solar core explaining the CAST result. On the other hand, the PVLAS experiment is taking place at the room temperature and therefore the vacuum condensate has nonzero value and the axion-photon coupling is present giving rise to the PVLAS signal for the axion.

This idea is consistent with all known experimental observations in particle physics and astrophysics. We predict that the axion must be accompanied by a twin particle with mass about 100 times that of the electron which undergoes the condensation and is responsible for our effect. It can be produced in the decay of heavy quark bound states, which can provide a way to test our model.

[1] P.Sikivie, Phys. Rev. Lett. 51, 1415 (1983)
[2] S.Andriamonje [CAST Collaboration], arXiv:hep-ex/0702006.
[3] E.Zavattini et al. [PVLAS Collaboration], Nucl. Phys. Proc. Suppl. 164, 264 (2007).
[4] R. N. Mohapatra and S. Nasri, "Reconciling the CAST and PVLAS Results", Phys. Rev. Letters 98, 050402 (2007) Link to Abstract

Store Light Here and Retrieve It at a Distance

Lene Vestergaard Hau, Mallinckrodt Professor of Physics and of Applied Physics [Photo courtsey: Jay Penni Photography, Harvard Univ]

In Bose-Einstein condensates (BECs), atoms are cooled to such low temperatures that they all occupy the same quantum state, even though they may be physically apart from each other. Making use of such quantum mechanically indistinguishable microscopic particles, Lene Hau and colleagues from Harvard University have been able to imprint a coherent pulse of light on a collection of ultracold atoms -- and then retrieve the same light pulse from a second set of atoms that is some distance away.

"We demonstrate that we can stop a light pulse in a supercooled sodium cloud, store the data contained within it, and totally extinguish it, only to reincarnate the pulse in another cloud two-tenths of a millimeter away," announced Lene Hau. In a paper published in Feb 8 issue of 'Nature', Lene Hau and her co-authors, Naomi S. Ginsberg and Sean R. Garner, reported their spectacular finding that the light pulse can be revived, and its information transferred between the two clouds of sodium atoms (or, the Bose-Einstein condensates -- illuminated with a control laser and cooled to just billionths of a degree above absolute zero), by converting the original optical pulse into a traveling matter wave. The matter wave is a matter-copy of the original pulse, traveling at a leisurely 200 meters per hour. When the matter pulse enters the second of the supercooled clouds which is illuminated with a control laser, it is readily converted back into light.

The results of this experiment provide a powerful means of controlling optical information and certainly will lead a way to future directions of optical communication. It could also have applications in the developing fields of quantum information processing and quantum cryptography.

Reference:
"Coherent control of optical information with matter wave dynamics"
Naomi S. Ginsberg, Sean R. Garner and Lene Vestergaard Hau
Nature 445, 623-626 (8 February 2007) Link to Abstract

Background Reading
Wikipedia page on Bose-Einstein Condensate
BEC homepage, JILA, Colorado
2Physics past posting on BEC

Upcoming Physics Conferences

Here is a selected list of forthcoming conferences in Physics. You are welcome to freely advertize Physics jobs or conferences in 2Physics by sending an email to 2Physics@gmail.com.

February 12-23: JIGSAW 2007 -- Joint Indo-German workshop and school on neutrinos in physics, astrophysics and cosmology (Mumbai, India)
February 24- March 3: 45th Schladming winter school on theoretical physics: conceptual and numerical challenges in femto- and peta-scale physics (Schladming, Austria)
February 25-March 3: Cesare lattes meeting on GRBS black holes and supernovae (Rio de Janeiro, Brazil)
February 26-27: The Nature of Time: A Minisymposium on Lessons from the Foundations of Relativity and Quantum Physics (Austin College, Sherman, Texas; Contact: Don Salisbury at dsalisbury@austincollege.edu.)
March 5-9: Foundations of quantum theory "special focus session" on foundations of quantum theory at the APS March Meeting (Denver, CO)
March 12-16: Nano and giga challenges (Tempe, AZ)
March 16-17: 23rd Pacific Coast Gravity Meeting (Caltech, Pasadena)
March 23-April 3: Quantum Gravity School (Zakopane, Poland)
March 24-29: The origin of galaxies (Otz Valley, nr. Innsbruck, Austria)
March 26-31: X hadron physics (Florianopolis, Brazil)
March 26-31: Nuclear Physics in Astrophysics (Dresden, Germany)
April 10-13: BICOS 2007 -- Bilbao Encounter On New Standard Cosmology (Bilbao, Spain)
April 23-27: Advanced computing and analysis techniques in physics (Amsterdam, The Netherlands)
May 10-12: The Hunt for Dark Matter: A Symposium on Collider, Direct and Indirect Searches (Fermilab, Batavia, IL)
May 12-16: Black Holes VI (White Point Resort, Prince Edward Island, Canada)
May 14-17: Origins of dark energy: conference and workshop (Hamilton, Canada)
May 14-18: Dark side of the universe (Villa Olmo, Italy)
May 14-18: Intl workshop on quantum noise (Caloundra, Australia)
May 18-20: 12th Canadian Conference on General Relativity and Relativistic Astrophysics (Fredericton, New Brunswick, Canada)
May 18-20: Workshop: excursions in the dark (Waterloo, Canada)
May 20-26: Matter and Energy in the Universe: from nucleosynthesis to cosmology (Chateau de Blois, France)
May 28-June 22: Theoretical advanced study institute (TASI) in elementary particle physics: "String Universe" (Boulder, Colorado, USA)
June 1-5: Central European workshop on quantum optics, 14th edition (Palermo, Italy)
June 4-7: 6th intl conference on nuclear and radiation physics (Almaty, Kazakhstan)
June 5-9: Annual APS Division of Atomic, Molecular and Optical Physics Meeting (Calgary, Canada)
June 10-13: From Quantum to Cosmos II -- Space-based Research in Fundamental Physics and Quantum Technologies (Bremen, Germany)
June 11-22: Summer school on particle physics (Trieste, Italy)
June 11-29: Physics at TeV colliders (Les Houches, France)
June 16-20: 4th intl workshop on quantum chromodynamics - theory and experiment (Bari, Italy)
June 18-20 SciNeGHE07: Fifth Workshop on Science with the New Generation of High Energy Gamma-ray Experiments (Villa Mondragone, Frascati, Rome, Italy)
June 18-22: School on attractor mechanism (Frascati, Italy)
June 22-July 3: 19th Petrov school -- summer school-seminar on recent problems in theoretical and mathematical physics (Kazan, Russia)
June 26-29: Physics in collision symposium on elementary and astro-particle physics (Annecy, France)
July 2-27: ESF school of theoretical physics: string theory and the real world (Les Houches, France)
July 8-14: 7th Edoardo Amaldi Conference on Gravitational waves (Sydney, Australia)
July 13-17: 'Cosmology and Strings' Workshop (ICTP, Trieste, Italy)
July 26-August 1: 15th intl conference on supersymmetry and the unification of fundamental interactions (Karlsruhe, Germany)
July 30-August 11: Cosmology and particle physics beyond the standard models (Cargese, France)
August 23-29: 13th Lomonosov conferences on elementary particle physics (Moscow, Russia)
September 2-6: Photons, atoms, and qubits (Royal Society, London, UK)
September 3-7: 3rd intl conference on physics and control (Potsdam, Germany)
September 2-7: Quantum Field Theory (Leipzig, Germany)
October 1-5: Planets to Dark Energy (Manchester,UK)
October 11-13: Algebra, geometry, and mathematical physics (Göteborg, Sweden)