Commentary: Intentional Observer Effects on Quantum Randomness: A Bayesian Analysis Reveals Evidence Against Micro-Psychokinesis

The paper titled `Intentional Observer Effects on Quantum Randomness: A Bayesian Analysis Reveals Evidence Against Micro-Psychokinesis', published in Frontiers of Psychology in March 2018, reports on a mind-matter experiment with the main result of strong evidence against Micro-Psychokinesis. Despite this conclusion, the authors interpret the observed pattern in their data as possible evidence for Micro-Psychokinesis, albeit of a different kind. Suggesting a connection to some existing models, the authors put forward the hypothesis that a higher frequency of slow data variations can be observed in their experiment data than in a set of control data. This commentary analyses this claim and concludes that the variation in the data motivating this hypothesis would show up just by chance with a probability of p=0.328 under a null hypothesis. Therefore, there is no evidence for the hypothesis of faster data variations, and thus for this kind of suggested Micro-Psychokinesis in this experiment

On the possibility of Vacuum-QED measurements with gravitational wave detectors

Quantum electro dynamics (QED) comprises virtual particle production and thus gives rise to a refractive index of the vacuum larger than unity in the presence of a magnetic field. This predicted effect has not been measured to date, even after considerable effort of a number of experiments. It has been proposed by other authors to possibly use gravitational wave detectors for such vacuum QED measurements, and we give this proposal some new consideration in this paper. In particular we look at possible source field magnet designs and further constraints on the implementation at a gravitational wave detector. We conclude that such an experiment seems to be feasible with permanent magnets, yet still challenging in its implementation.Comment: 11 pages, 10 figure

Commentary: intentional observer effects on quantum randomness: a bayesian analysis reveals evidence against micro-psychokinesis

In the article [Maier2018] the authors report on a mind-matter experiment comprising an impressive 12.571 subjects in a Micro-Psychokinesis (Micro-PK) task. The main result of that study, testing the aggregate sum of the data against its expectation value, is reported as strong evidence against Micro-PK. Despite this conclusion, the authors move ahead and interpret a post-hoc observed pattern in their data as possible evidence for Micro-PK, albeit of a different kind. The authors put forward the hypothesis that a higher frequency of slow data variations can be observed in their experiment data than in a single set of control data. They propose that Micro-PK-Effects show up not in the aggregate sum, but in fluctuations (i.e. in the time sequence) of their data: “Interestingly, there seems to be a pattern of repeated change.” The authors connect this possible observation with theories of von Lucadou and others (e.g.[Luc2006,Luc2007,Luc2015]), extended by their own thoughts about possible decline effects in Parapsychology experiments. As a smaller remark, it seems to this author that there is a confusion here about decline of the primary effect size and a decline as observed in a cumulative z-score representation of data, as used by the authors. A constant oscillation of an original effect size always leads to a decline of oscillations in a cumulative z-score plot, as more data goes into the z-score calculation. Likewise, this confusion is also evident in Figure 7 of [Maier2018]. The cumulative z-scores in those figures have a constant oscillation amplitude, which is only possible with an oscillating and exponentially growing effect size in the original data

Overview and Status of Advanced Interferometers for Gravitational Wave Detection

The world-wide network of km-scale laser interferometers is aiming at the detection of gravitational waves of astrophysical origin. The second generation of these instruments, called advanced detectors has been, or is in the process of being completed, and a first observational run with the Advanced LIGO interferometers has been performed late in 2015. The basic functionality of advanced detectors is discussed, along with specific features and status updates of the individual projects

Making it work : second generation interferometry in GEO 600!

[no abstract

Phase Control of Squeezed Vacuum States of Light in Gravitational Wave Detectors

Quantum noise will be the dominant noise source for the advanced laser interferometric gravitational wave detectors currently under construction. Squeezing-enhanced laser interferometers have been recently demonstrated as a viable technique to reduce quantum noise. We propose two new methods of generating an error signal for matching the longitudinal phase of squeezed vacuum states of light to the phase of the laser interferometer output field. Both provide a superior signal to the one used in previous demonstrations of squeezing applied to a gravitational-wave detector. We demonstrate that the new signals are less sensitive to misalignments and higher order modes, and result in an improved stability of the squeezing level. The new signals also offer the potential of reducing the overall rms phase noise and optical losses, each of which would contribute to achieving a higher level of squeezing. The new error signals are a pivotal development towards realizing the goal of 6 dB and more of squeezing in advanced detectors and beyond

Terrestrial Laser Interferometers

Terrestrial laser interferometers for gravitational-wave detection made the landmark first detection of gravitational waves in 2015. We provide an overview of the history of how these laser interferometers prevailed as the most promising technology in the search for gravitational waves. We describe their working principles and their limitations, and provide examples of some of the most important technologies that enabled their construction. We introduce each of the four large-scale laser interferometer gravitational-wave detectors in operation around the world today and provide a brief outlook for the future of ground-based detectors.Comment: Invited chapter for "Handbook of Gravitational Wave Astronomy" (Eds. C. Bambi, S. Katsanevas and K. Kokkotas; Springer Singapore, 2021

Probing dark matter with polarimetry techniques

In this work, we propose polarimetry experiments to search for low-mass (sub-eV) bosonic field dark matter, including axions and axion-like particles. We show that a polarimetry configuration consisting of a thick birefringent solid inside a Fabry-P\'erot cavity is exceptionally sensitive to scalar field dark matter, which may cause oscillatory variations in the solid's thickness and refractive index. In addition, we show that a reconfiguration of this polarimetry experiment, in which two quarter-wave plates are placed inside the Fabry-P\'erot cavity instead of a thick birefringent solid, is very sensitive to axion-like particles. We investigate the possibility of using cross-correlation of twin polarimeters to increase the sensitivity of the experiment, which in turn could allow us to explore unexplored parts of the parameter space and potentially detect a signal in either dark matter scenario

High power and ultra-low-noise photodetector for squeezed-light enhanced gravitational wave detectors

Current laser-interferometric gravitational wave detectors employ a self-homodyne readout scheme where a comparatively large light power (5–50 mW) is detected per photosensitive element. For best sensitivity to gravitational waves, signal levels as low as the quantum shot noise have to be measured as accurately as possible. The electronic noise of the detection circuit can produce a relevant limit to this accuracy, in particular when squeezed states of light are used to reduce the quantum noise. We present a new electronic circuit design reducing the electronic noise of the photodetection circuit in the audio band. In the application of this circuit at the gravitational-wave detector GEO 600 the shot-noise to electronic noise ratio was permanently improved by a factor of more than 4 above 1 kHz, while the dynamic range was improved by a factor of 7. The noise equivalent photocurrent of the implemented photodetector and circuit is about 5 µA/ √\ud Hz above 1 kHz with a maximum detectable photocurrent of 20 mA. With the new circuit, the observed squeezing level in GEO 600 increased by 0.2 dB. The new circuit also creates headroom for higher laser power and more squeezing to be observed in the future in GEO 600 and is applicable to other optics experiments