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Ulrich Johann

Other affiliations: Airbus Group, Dornier Flugzeugwerke
Bio: Ulrich Johann is an academic researcher from Airbus Defence and Space. The author has contributed to research in topics: Interferometry & Wavefront. The author has an hindex of 16, co-authored 58 publications receiving 1144 citations. Previous affiliations of Ulrich Johann include Airbus Group & Dornier Flugzeugwerke.


Papers
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Journal ArticleDOI
Michele Armano1, Heather Audley2, G. Auger3, J. Baird4, Massimo Bassan5, Pierre Binétruy3, M. Born2, Daniele Bortoluzzi6, N. Brandt7, M. Caleno1, L. Carbone6, Antonella Cavalleri8, A. Cesarini6, Giacomo Ciani6, G. Congedo6, A. M. Cruise9, Karsten Danzmann2, M. de Deus Silva1, R. De Rosa, M. Diaz-Aguilo10, L. Di Fiore, Ingo Diepholz2, G. Dixon9, Rita Dolesi6, N. Dunbar7, Luigi Ferraioli11, Valerio Ferroni6, Walter Fichter, E. D. Fitzsimons12, R. Flatscher7, M. Freschi1, A. F. García Marín2, C. García Marirrodriga1, R. Gerndt7, Lluis Gesa10, Ferran Gibert6, Domenico Giardini11, R. Giusteri6, F. Guzmán2, Aniello Grado13, Catia Grimani14, A. Grynagier, J. Grzymisch1, I. Harrison15, Gerhard Heinzel2, M. Hewitson2, Daniel Hollington4, D. Hoyland9, Mauro Hueller6, Henri Inchauspe3, Oliver Jennrich1, Ph. Jetzer16, Ulrich Johann7, B. Johlander1, Nikolaos Karnesis2, B. Kaune2, N. Korsakova2, Christian J. Killow17, J. A. Lobo10, Ivan Lloro10, L. Liu6, J. P. López-Zaragoza10, R. Maarschalkerweerd15, Davor Mance11, V. Martín10, L. Martin-Polo1, J. Martino3, F. Martin-Porqueras1, S. Madden1, Ignacio Mateos10, Paul McNamara1, José F. F. Mendes15, L. Mendes1, A. Monsky2, Daniele Nicolodi6, Miquel Nofrarías10, S. Paczkowski2, Michael Perreur-Lloyd17, Antoine Petiteau3, P. Pivato6, Eric Plagnol3, P. Prat3, U. Ragnit1, B. Rais3, Juan Ramos-Castro18, J. Reiche2, D. I. Robertson17, H. Rozemeijer1, F. Rivas10, G. Russano6, J Sanjuán10, P. Sarra, A. Schleicher7, D. Shaul4, Jacob Slutsky19, Carlos F. Sopuerta10, Ruggero Stanga20, F. Steier2, T. J. Sumner4, D. Texier1, James Ira Thorpe19, C. Trenkel7, Michael Tröbs2, H. B. Tu6, Daniele Vetrugno6, Stefano Vitale6, V Wand2, Gudrun Wanner2, H. Ward17, C. Warren7, Peter Wass4, D. Wealthy7, W. J. Weber6, L. Wissel2, A. Wittchen2, A. Zambotti6, C. Zanoni6, Tobias Ziegler7, Peter Zweifel11 
TL;DR: The first results of the LISA Pathfinder in-flight experiment demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density.
Abstract: We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2 +/- 0.1 fm s(exp -2)/square root of Hz, or (0.54 +/- 0.01) x 10(exp -15) g/square root of Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8 +/- 0.3) fm square root of Hz, about 2 orders of magnitude better than requirements. At f less than or equal to 0.5 mHz we observe a low-frequency tail that stays below 12 fm s(exp -2)/square root of Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

523 citations

Journal ArticleDOI
TL;DR: The Macroscopic Quantum Resonators (MAQROI) project as mentioned in this paper proposes a mission to probe the quantum transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments.
Abstract: Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schrodinger’s cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored ‘quantum-classical’ transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments.

99 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a compact heterodyne interferometer utilizing polarizing optics combined with the method of differential wavefront sensing (DWS) serving as a demonstrator for a complete optical readout system of the proof mass translation and attitude aboard the LISA satellites.
Abstract: The Laser Interferometer Space Antenna (LISA) aims at detecting gravitational waves by referencing heterodyne interferometry to free-flying (inertial) proof masses, located at the corners of a triangle with 5 million kilometers arm length. The position of each proof mass with respect to the associated satellite must be measured with 1 pm Hz−1/2-sensitivity in translation measurement and below 10 nrad Hz−1/2-sensitivity in attitude. In this paper, we present a compact heterodyne interferometer utilizing polarizing optics combined with the method of differential wavefront sensing (DWS) serving as a demonstrator for a complete optical readout system of the proof mass translation and attitude aboard the LISA satellites. Our interferometer is based on a highly symmetric design, where reference and measurement beam have similar optical paths and equal polarization and frequency. Intensity stabilization of the laser radiation, phaselock of the laser frequencies at the fiber outputs and a digital phase measurement based on a field programmable gate array (FPGA) are implemented to achieve noise levels below 10 pm Hz−1/2 and 10 nrad Hz−1/2, respectively, for frequencies >10−2 Hz.

73 citations

Journal ArticleDOI
TL;DR: In this paper, a heterodyne Mach-Zehnder interferometer was selected as the baseline for the SMART-2 mission and its design and expected performance were described.
Abstract: The interferometer of the LISA technology package (LTP) on SMART-2 is needed to verify the performance of the gravitational sensors by monitoring the distance between two test masses with a noise level of 10 pm Hz −1/2 between 3 mHz and 30 mHz. It must continuously track the motion of the test mass distance while that distance changes by many µ mw ith a speed of up to 20 µ ms −1 ,w ithout losing track of the sign of the motion and without exerting any influence on the test masses that might lead to a motion above that level. As a result of a detailed comparison study, a heterodyne Mach– Zehnder interferometer was selected as the baseline for the SMART-2 mission. Its design and expected performance are described in this paper.

66 citations

Journal ArticleDOI
TL;DR: The LISA Technology Package (LTP) is a technology demonstration mission in preparation for the LISA space-borne gravitational wave detector as discussed by the authors, which is a central part of the LTP is the optical metrology package (heterodyne interferometer with phasemeter) that measures the distance between two test masses with a noise level of 10 pm Hz−1/2 between 3 mHz and 30 mHz.
Abstract: The LISA Technology Package (LTP), to be launched by ESA in 2008, is a technology demonstration mission in preparation for the LISA space-borne gravitational wave detector. A central part of the LTP is the optical metrology package (heterodyne interferometer with phasemeter) that measures the distance between two test masses with a noise level of 10 pm Hz−1/2 between 3 mHz and 30 mHz and also the test mass alignment with a noise level of <10 nrad Hz−1/2. An engineering model of the interferometer has been built and environmentally tested. Extensive functionality and performance tests were conducted. This paper reports on the successful test results.

62 citations


Cited by
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01 Dec 1982
TL;DR: In this article, it was shown that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M/M)K where κ is the surface gravity of the body.
Abstract: QUANTUM gravitational effects are usually ignored in calculations of the formation and evolution of black holes. The justification for this is that the radius of curvature of space-time outside the event horizon is very large compared to the Planck length (Għ/c3)1/2 ≈ 10−33 cm, the length scale on which quantum fluctuations of the metric are expected to be of order unity. This means that the energy density of particles created by the gravitational field is small compared to the space-time curvature. Even though quantum effects may be small locally, they may still, however, add up to produce a significant effect over the lifetime of the Universe ≈ 1017 s which is very long compared to the Planck time ≈ 10−43 s. The purpose of this letter is to show that this indeed may be the case: it seems that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M/M)K where κ is the surface gravity of the black hole1. As a black hole emits this thermal radiation one would expect it to lose mass. This in turn would increase the surface gravity and so increase the rate of emission. The black hole would therefore have a finite life of the order of 1071 (M/M)−3 s. For a black hole of solar mass this is much longer than the age of the Universe. There might, however, be much smaller black holes which were formed by fluctuations in the early Universe2. Any such black hole of mass less than 1015 g would have evaporated by now. Near the end of its life the rate of emission would be very high and about 1030 erg would be released in the last 0.1 s. This is a fairly small explosion by astronomical standards but it is equivalent to about 1 million 1 Mton hydrogen bombs. It is often said that nothing can escape from a black hole. But in 1974, Stephen Hawking realized that, owing to quantum effects, black holes should emit particles with a thermal distribution of energies — as if the black hole had a temperature inversely proportional to its mass. In addition to putting black-hole thermodynamics on a firmer footing, this discovery led Hawking to postulate 'black hole explosions', as primordial black holes end their lives in an accelerating release of energy.

2,947 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a review of the application of atomic physics to address important challenges in physics and to look for variations in the fundamental constants, search for interactions beyond the standard model of particle physics and test the principles of general relativity.
Abstract: Advances in atomic physics, such as cooling and trapping of atoms and molecules and developments in frequency metrology, have added orders of magnitude to the precision of atom-based clocks and sensors. Applications extend beyond atomic physics and this article reviews using these new techniques to address important challenges in physics and to look for variations in the fundamental constants, search for interactions beyond the standard model of particle physics, and test the principles of general relativity.

1,077 citations

Journal ArticleDOI
TL;DR: In this article, the authors review early universe sources that can lead to cosmological backgrounds of GWs and discuss the basic characteristics of present and future GW detectors, including advanced LIGO, advanced Virgo, the Einstein telescope, KAGRA, and LISA.
Abstract: Gravitational waves (GWs) have a great potential to probe cosmology. We review early universe sources that can lead to cosmological backgrounds of GWs. We begin by presenting proper definitions of GWs in flat space-time and in a cosmological setting (section 2). Following, we discuss the reasons why early universe GW backgrounds are of a stochastic nature, and describe the general properties of a stochastic background (section 3). We recap current observational constraints on stochastic backgrounds, and discuss the basic characteristics of present and future GW detectors, including advanced LIGO, advanced Virgo, the Einstein telescope, KAGRA, and LISA (section 4). We then review in detail early universe GW generation mechanisms, as well as the properties of the GW backgrounds they give rise to. We classify the backgrounds in five categories: GWs from quantum vacuum fluctuations during standard slow-roll inflation (section 5), GWs from processes that operate within extensions of the standard inflationary paradigm (section 6), GWs from post-inflationary preheating and related non-perturbative phenomena (section 7), GWs from first order phase transitions related or not to the electroweak symmetry breaking (section 8), and GWs from general topological defects, and from cosmic strings in particular (section 9). The phenomenology of these early universe processes is extremely rich, and some of the GW backgrounds they generate can be within the reach of near-future GW detectors. A future detection of any of these backgrounds will provide crucial information on the underlying high energy theory describing the early universe, probing energy scales well beyond the reach of particle accelerators.

643 citations

Journal ArticleDOI
Michele Armano1, Heather Audley2, G. Auger3, J. Baird4, Massimo Bassan5, Pierre Binétruy3, M. Born2, Daniele Bortoluzzi6, N. Brandt7, M. Caleno1, L. Carbone6, Antonella Cavalleri8, A. Cesarini6, Giacomo Ciani6, G. Congedo6, A. M. Cruise9, Karsten Danzmann2, M. de Deus Silva1, R. De Rosa, M. Diaz-Aguilo10, L. Di Fiore, Ingo Diepholz2, G. Dixon9, Rita Dolesi6, N. Dunbar7, Luigi Ferraioli11, Valerio Ferroni6, Walter Fichter, E. D. Fitzsimons12, R. Flatscher7, M. Freschi1, A. F. García Marín2, C. García Marirrodriga1, R. Gerndt7, Lluis Gesa10, Ferran Gibert6, Domenico Giardini11, R. Giusteri6, F. Guzmán2, Aniello Grado13, Catia Grimani14, A. Grynagier, J. Grzymisch1, I. Harrison15, Gerhard Heinzel2, M. Hewitson2, Daniel Hollington4, D. Hoyland9, Mauro Hueller6, Henri Inchauspe3, Oliver Jennrich1, Ph. Jetzer16, Ulrich Johann7, B. Johlander1, Nikolaos Karnesis2, B. Kaune2, N. Korsakova2, Christian J. Killow17, J. A. Lobo10, Ivan Lloro10, L. Liu6, J. P. López-Zaragoza10, R. Maarschalkerweerd15, Davor Mance11, V. Martín10, L. Martin-Polo1, J. Martino3, F. Martin-Porqueras1, S. Madden1, Ignacio Mateos10, Paul McNamara1, José F. F. Mendes15, L. Mendes1, A. Monsky2, Daniele Nicolodi6, Miquel Nofrarías10, S. Paczkowski2, Michael Perreur-Lloyd17, Antoine Petiteau3, P. Pivato6, Eric Plagnol3, P. Prat3, U. Ragnit1, B. Rais3, Juan Ramos-Castro18, J. Reiche2, D. I. Robertson17, H. Rozemeijer1, F. Rivas10, G. Russano6, J Sanjuán10, P. Sarra, A. Schleicher7, D. Shaul4, Jacob Slutsky19, Carlos F. Sopuerta10, Ruggero Stanga20, F. Steier2, T. J. Sumner4, D. Texier1, James Ira Thorpe19, C. Trenkel7, Michael Tröbs2, H. B. Tu6, Daniele Vetrugno6, Stefano Vitale6, V Wand2, Gudrun Wanner2, H. Ward17, C. Warren7, Peter Wass4, D. Wealthy7, W. J. Weber6, L. Wissel2, A. Wittchen2, A. Zambotti6, C. Zanoni6, Tobias Ziegler7, Peter Zweifel11 
TL;DR: The first results of the LISA Pathfinder in-flight experiment demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density.
Abstract: We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2 +/- 0.1 fm s(exp -2)/square root of Hz, or (0.54 +/- 0.01) x 10(exp -15) g/square root of Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8 +/- 0.3) fm square root of Hz, about 2 orders of magnitude better than requirements. At f less than or equal to 0.5 mHz we observe a low-frequency tail that stays below 12 fm s(exp -2)/square root of Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

523 citations

Journal ArticleDOI
TL;DR: In this paper, the LISA space-based interferometer was used to detect the stochastic gravitational wave background produced from different mechanisms during inflation, focusing on well-motivated scenarios.
Abstract: We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

418 citations