Quanta, lasers and gravitational waves

The Albert Einstein Institute presents an extensive programme within the framework of the DPG Spring Meeting

March 13, 2013

Around 1700 physicists will meet from 18 to 22 March 2013 for the Spring Meeting of the Deutsche Physikalische Gesellschaft (DPG) at Leibniz Universität Hannover. At the meeting, scientists from the Max Planck Institute for Gravitational Physics and the Institute for Gravitational Physics Leibniz Universität (Albert Einstein Institute; AEI) Hannover will present their most recent research results in quantum, laser and gravitational wave physics in approx. 30 specialized lectures. In addition, the Institute has also invited the meeting participants to visit the laboratories and the GEO600 gravitational wave detector. With its own stand and a special lecture the Institute will also provide information about the planned satellite mission LISA and the shared computer project Einstein@Home.

Guided tour and excursions (registration required):

Advanced LIGO 200-Watt Laser & Squeezing-Lab 
Tuesday, 19 Mar., 1:45 p.m., 2:25 p.m. and 3:05 p.m.

10-Meter Prototype 
Thursday, 21 Mar., 1:45 p.m., 2:15 p.m. and 2:45 p.m.

Computercluster Atlas 
Thursday, 21 Mar., 1:45 p.m., 2:15 p.m. and 2:45 p.m.

Gravitational Wave Detector GEO600 
Thursday, 21 Mar., 11:15 a.m.

Talk: “Listen to the Universe” 
Thursday, 21 Mar., 6:30 p.m.

Gravitational wave astronomy at the Albert Einstein Institute Hannover

Gravitational waves are tiny ripples in spacetime whose existence was predicted by Albert Einstein in his general theory of relativity as early as 1916. The waves are emitted in cosmic events such as supernova explosions, merging black holes and compact neutron stars. Their direct measurement will open a new window onto the universe and herald a new era in astronomy; however, to date, it has not been possible to directly prove the waves from space. Under the motto “Thinking beyond Einstein”, the AEI Hannover is working in several areas to enable the first direct detection of gravitational waves.

In an international collaboration, the AEI operates the GEO600 gravitational detector in Ruthe, around 20 kilometres south of Hannover. Highly-precise measurements by the interferometric detector with 600-metre long arms are intended to directly detect the ripples in timespace. GEO600 is currently the only large gravitational-wave detector worldwide in active measuring mode and, at the same time, is being upgraded in the “GEO-HF” programme in order to improve its sensitivity to high-frequency gravitational waves.

The laser light sources used by the GEO600 were developed at the AEI Hannover together with the Laser Zentrum Hannover (LZH), and are among the most precise lasers worldwide. Only lasers whose colour, intensity, beam form and beam position are permanently stable are suitable for the detection of faint gravitational waves. The AEI also plans and constructs, together with the LZH, the high-performance laser systems of the large LIGO gravitational wave detectors in the USA.

Moreover, the AEI is already working on the next generation of earthbound interferometric gravitational wave detectors. To this effect, the Institute is operating a prototype with an arm length of 10 metres. Through the use of new mechanical and optical superstructures, data collection technology and special laser lights, the measurement accuracy will be further enhanced.

Another working group at the AEI is researching how the quantum properties of the laser light being used can be altered in order to minimize its unavoidable noise which ultimately limits the precision of classic measurements. To this end, the AEI is developing and operating the world’s best “squeezed light sources”, which are today already in use in the GEO600. With these special lasers, the AEI researchers are also tackling issues in metrology, quantum communication and basic research.

However, the scientists’ work isn’t limited to earthbound measurements. The AEI is also playing a role in the development of the GRACE Follow-on Satellite Mission (Gravity Recovery and Climate Experiment Follow-on). The twin satellites are expected, starting in 2017, to make valuable contributions to global climate research through continual measurements of the Earth’s gravity field. For this, the Institute has developed the employed laser interferometry for measuring the distance of the satellites.

The path to measuring gravitational waves also extends into outer space. In around 15 years, a mission is being planned with three satellites that will follow the Earth in its orbit around the Sun with the intent of measuring extremely low-frequency gravitational waves, for example from merging very-massive black holes. The AEI is the world’s leading research institution in the development of the project called LISA (Laser Interferometer Space Antenna). It is planned that the three satellites make use of the laser interferometry developed at the AEI in order to capture the changes in distance caused by gravitational waves. Already in 2015 the LISA Pathfinder satellite will be launched into space and demonstrate these methods. The AEI is supplying the senior scientist for the project as well as the laser measurement technology.

For the evaluation of the huge amount of data being generated by the gravitational wave detectors, the AEI operates “Atlas”, the world’s biggest computer cluster for gravitational wave research. Furthermore, the Institute is playing a major role in the shared computing project Einstein@Home, which, thanks to the help of hundreds of thousands of volunteers from around the globe, is analyzing data. These citizen scientists make available their idle computing time on their PCs and have already made numerous astronomical discoveries.

Further information about the research being conducted at the AEI will be available in the specialized lectures by the AEI researchers during the meeting, the guided tours through the Institute’s labs and the Atlas computer cluster, as well as the trip to the GEO600 gravitational wave detector. An information stand for LISA and Einstein@Home will be set up in the main building of Leibniz Universität for the entire duration of the meeting. On Thursday there will be a talk entitled “Listen to the Universe” with additional background information about these two projects.

Guided tours and excursions

Registration for all guided tours at the DPG Meeting Office (Main university building, C109) 

Tuesday, 19 March 2013

Advanced LIGO 200-Watt Laser & Squeezing-Lab 
For the second generation of gravitational wave detectors, powerful laser output is required in order to improve the sensitivity that is restricted by shot noise. Technical laser noise from high-power lasers, however, couples strongly onto the output signal of these detectors and must therefore be reduced. The 200W laser systems developed for the Advanced LIGO detector were stabilized with regard to their spatial beam profile, their beam position fluctuations, their performance and frequency noises. In our lab, you can observe the so-called “reference system” which is identical to the systems installed in the detectors. 

The Quantum Interferometry working group currently makes use of ca. ten squeeze light sources, which provide a nonstandard noise suppression of up to 12.7 dB. Application areas are metrology, quantum communication and in basic research. The lab that can be visited will present two example experiments. 

Point of departure at the meeting office (Main university building, room C109)

Tues., 19 Mar., 1:45 p.m., 2:25 p.m. and 3:05 p.m.

Maximum 16 participants per group

Duration: ca. 40 minutes

Thursday, 21 March 201310-Meter Prototype

On the 10-Meter-Prototype of the AEI, we develop technologies for improving the sensitivity of interferometric gravitational wave detectors. As part of this, we are constructing a Michelson Interferometer with an armlength of 10 metres and 100-gram mirrors whose sensitivity in the entire measuring range is determined only through the quantum noises. We are planning, with the help of squeezed laser light, to break through the quantum noise barrier and to make accessible the regime of non-destructive quantum measurements for experiments such as e.g. the entanglement of macroscopic objects.

Point of departure at the meeting office (Main university building, room C109)

Thur., 21 Mar., 1:45 p.m., 2:15 p.m. and 2:45 p.m.

Maximum 10 participants per group

Duration: ca. 30 minutes

Computercluster Atlas 
Atlas is the world’s biggest computer cluster in gravitational wave research. Currently, Atlas consists of just about 1800 computers with around 7000 CPU cores with over 2 PByte memory capacity and 12 TByte main memory. On annual average, it is therefore, with over 90% capacity, almost in full use. The more than 500 scientists who have access to the system analyze the data of the GEO600, LIGO and VIRGO gravitational wave detectors that has been recorded over the past few years.

Point of departure at the meeting office (Main university building, room C109)

Thur., 21 Mar., 1:45 p.m., 2:15 p.m. and 2:45 p.m.

Maximum 15 participants per group

Duration: ca. 30 minutes

GEO600 Gravitational wave detector 

Free bus transfer brings you to Ruthe, ca. 20 kilometres south of Hannover. There, you will have the chance to visit GEO600, an interferometric detector with an arm length of 600 metres which will enable the direct measurement of gravitational waves. The tiny ripples in spacetime are borne of cosmic events such as supernova explosions or merging of neutron stars and were predicted by Albert Einstein back in 1916. In the “Astrowatch” programme, GEO600, as the only interferometric detector in active measuring mode in the world, is paying close attention to catch gravitational waves. 

The GEO600 gravitational wave detector was constructed within the framework of a German-British collaboration and is a part of the LIGO Scientific Collaboration (LSC), in which we devise shared measurement programmes and jointly analyze our measurement data.

Meeting point in front of the main university building (between the lion statues)

Thur., 21 Mar., 

11:15 a.m.

Maximum 45 participants

Return before 3:00 p.m.

Info-Stand “LISA and Einstein@Home” 
Monday to Friday, main university building, in front of auditorium F142 

Please visit our stand, for information about the LISA satellite mission and the distributed computer project Einstein@Home. It is planned that LISA, a gravitational wave observatory in space, will begin its measurement work in around 15 years. Einstein@Home is already searching for waves from the cosmos with the help of hundreds of thousands of volunteers.

Talk “Listen to the Universe” 
Thursday, 21 March, 6:30 p.m., Bahlsensaal (auditorium F303) 
Simon Barke and Benjamin Knispel 

Two projects in which the Albert Einstein Institute is participating form the focus of this talk: the planned LISA space observatory and the distributed computer project Einstein@Home, which both in their own way are listening in to the cosmos in order to hunt down gravitational waves, as predicted by Albert Einstein as early as 1916. Gravitational waves are tiny ripples in spacetime, which have to date not been able to be directly measured and whose direct detection is set to usher in a new era in astronomy. 

LISA (Laser Interferometer Space Antenna) is the concept of a gravitational wave observatory in space. Three satellites, in never-before attained silence, extend a triangle of laser light with an edge length of millions of kilometres. This enables highly-precise measurements of the distance between the satellites, thanks to which tiny waves in spacetime can be detected. A mission based on this principle is planned to take up its work in space in around 15 year’s time. Then it will be possible for the first time to hear the dark side of our universe: black holes, white dwarves and perhaps even the echo of the Big Bang. 

Einstein@Home is a distributed computer project that is already searching for signals from rapidly rotating, compact neutron stars in the signals of the earthbound LIGO gravitational wave detectors. The project brings together hundreds of thousands of volunteers from around the globe, who make available the idle computing time on the PCs for the sake of data analysis. Einstein@Home has already discovered over 40 new neutron stars in the data of the large radio telescopes and is sifting through the data of the Fermi gamma satellite in the search for unknown gamma pulsars.

Talks by AEI scientists during the DPG Meeting 

Monday, 18 March 2013 

Q 1: Micromechanical oscillators I (room F 142) 
• 11:30 a.m. (Q 1.3) Cryogenic cooling of a Michelson-Sagnac Interferometer, Ramon Moghadas Nia, Henning Kaufer, Andreas Sawadsky und Roman Schnabel 
• 12:00 p.m. (Q 1.5) Anomalous dynamic back-action in interferometers: beyond the scaling law, Sergey Tarabrin, Farid Khalili, Klemens Hammerer, Henning Kaufer and Roman Schnabel 

Q 8: Micromechanic oscillators II (room F 142) 
• 2:00 p.m. (Q 8.1) Dissipative opto-mechanics in a membrane interferometer, Henning Kaufer, Andreas Sawadsky, Ramon Moghadas Nia, Sergey Tarabrin, Klemens Hammerer and Roman Schnabel

Wednesday, 20 March 2013 

Q 38: Precision measurements and metrology III (room E 001) 
• 2:00 p.m. (Q 38.1) Group report: Status of the LISA mission, Gerhard Heinzel 
• 2:30 p.m. (Q 38.2) LISA Pathfinder: Preparation of the operation in orbit, Heather Audley, Martin Hewitson, Natalia Korsakova, Jens Reiche, Gerhard Heinzel and Karsten Danzmann 
• 2:45 p.m. (Q 38.3) Towards the Quantum Limit: Update from the AEI 10-meter Prototype, Tobin Fricke and The AEI 10 meter Prototype team 
• 3:00 p.m. (Q 38.4) GRACE Follow-on - An Overview, Gunnar Stede, Daniel Schütze, Vitali Müller, Alexander Görth, Christoph Mardt, Oliver Gerberding, Benjamin Sheard, Gerhard Heinzel and Karsten Danzmann 
• 3:30 p.m. (Q 38.6) Suspension Platform Interferometer for the AEI 10 m-Prototyp-Interferometer, Sina Köhlenbeck for the AEI 10m Prototype Team 
• 3:45 p.m. (Q 38.7) Seismic isolation for the 10 m Prototype, Gerald Bergmann for the AEI 10m Prototype Team 

Q 41: Quantum information: Concepts and methods III (room E 214) 
• 2:30 (Q 41.2) Concept for a remote, balanced receiver for quantum key distribution, Jan Gniesmer, Vitus Händchen, Tobias Eberle and Roman Schnabel

Thursday, 21 March 2013 

Q 50: Laser applications (room F 142) 
• 2:00 p.m. (Q 50.1) Group report: Progress in the GEO-HF Upgrade Programme, Christoph Affeldt 
• 2:30 p.m. (Q 50.2) Thermal lens measurement in commonly used optical components, Christina Bogan, Patrick Kwee, Sabina Huttner, Stefan Hild, Benno Willke and Karsten Danzmann 
• 3:15 p.m. (Q 50.5) Development of an Optical Ground Support Equipment Unit for the GRACE follow-on Mission, Alexander Görth, Oliver Gerberding, Christoph Mahrdt, Vitali Müller, Daniel Schütze, Benjamin Sheard, Gunnar Stede, Jose Sanjuan, Martin Gohlke, Claus Braxmaier, Gerhard Heinzel, Karsten Danzmann and Kolja  Nicklaus 
• 3:30 p.m. (Q 50.6) A high power beam in high-order Laguerre-Gauss mode, Christina Bogan, Ludovico Carbone, Andreas Freise, Benno Willke and Karsten Danzmann

Q 51: Precision measurements and metrology IV (room F 128)
• 2:00 p.m. (Q 51.1) Group report: A prototype optical bench for the Laser Interferometer Space Antenna, Michael Tröbs, Maike Lieser and the LISA Optical Bench Team 
• 2:45 p.m. (Q 51.3) Ground-based characterisation of the LISA Pathfinder optical measurement system, Andreas Wittchen, Martin Hewitson, Heather Audley, Natalia Korsakova, Gerhard Heinzel and Karsten Danzmann 
• 3:15 p.m. (Q 51.5) Breadboard model of the LISA Phasemeter, Oliver Gerberding, Simon Barke, Joachim Kullmann, Ioury Bykov, Juan Josè Esteban Degaldo, Gerhard Heinzel and Karsten Danzmann 
• 3:30 p.m. (Q 51.6) Laser frequency stabilisation for the AEI 10m Prototype Interferometer, Manuela Hanke for the AEI 10 m Prototype team 
• 3:45 p.m. (Q 51.7) Development of photoreceivers for space-based interferometry, Germán Fernández, Gerhard Heinzel und Karsten Danzmann 

Q 54: Quantum information: Photons and nonclassical light I (room E 001) 
• 2:30 p.m. (Q 54.2) Realization of quantum up-conversion of squeezed light from 1550 nm to 532 nm, Petrissa Zell, Christina E. Vollmer, Christoph Baune, Aiko Samblowski, Jaromír Fiurášek and Roman Schnabel

Friday, 22 March 2013 

Q 64: Precision measurements and metrology VI (room E 001) 
• 2:15 p.m. (Q 64.2) Laser ranging for GRACE follow-on, Daniel Schütze, Gunnar Stede, Vitali Müller, Alexander Görth, Oliver Gerberding, Christoph Mahrdt, Benjamin Sheard, Gerhard Heinzel and Karsten Danzmann 
• 2:30 p.m. (Q 64.3) General Astigmatic Gaussian Beam Model, Evgenia Kochkina, Dennis Schmelzer, Gudrun Wanner, Gerhard Heinzel and Karsten Danzmann 
• 3:00 p.m. (Q 64.5) Digital unterstützte heterodyn Interferometrie, Katharina-Sophie Isleif, Sina Köhlenbeck, Oliver Gerberding, Stefan Goßler, Gerhard Heinzel and Karsten Danzmann 
• 3:15 p.m. (Q 64.6) Coating thermal noise interferometer, Tobias Westphal and the AEI 10m Prototype team 
• 3:30 p.m. (Q 64.7) Control of optical cavities in light-shining-through-a-wall experiments, Robin Baehre 

Q 66: Quantum effects: Entanglement and decoherence II (room A 310) 
• 3:00 p.m. (Q 66.4) Quantum-Dense Read-Out for Interferometric Measurements, Melanie Meinders, Sebastian Steinlechner, Jöran Bauchrowitz, Helge Müller-Ebhardt, Karsten Danzmann and Roman Schnabel 

Q 68: Quantum information: Photons and nonclassical light II (room F 142) 
• 3:30 p.m. (Q 68.7) Entanglement distribution by separable states, Daniela Schulze, Christina E. Vollmer, Tobias Eberle, Vitus Händchen, Jaromír Fiurášek and Roman Schnabel

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