There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of $1.0 \times 10^{-21}$. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 {\sigma}. The source lies at a luminosity distance of $410^{+160}_{-180}$ Mpc corresponding to a redshift $z = 0.09^{+0.03}_{-0.04}$. In the source frame, the initial black hole masses are $36^{+5}_{-4} M_\odot$ and $29^{+4}_{-4} M_\odot$, and the final black hole mass is $62^{+4}_{-4} M_\odot$, with $3.0^{+0.5}_{-0.5} M_\odot c^2$ radiated in gravitational waves. All uncertainties define 90% credible intervals.These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102

Observation of Gravitational Waves from a Binary Black Hole Merger

Quantum networks provide opportunities and challenges across a range of intellectual and technical frontiers, including quantum computation, communication and metrology. The realization of quantum networks composed of many nodes and channels requires new scientific capabilities for generating and characterizing quantum coherence and entanglement. Fundamental to this endeavour are quantum interconnects, which convert quantum states from one physical system to those of another in a reversible manner. Such quantum connectivity in networks can be achieved by the optical interactions of single photons and atoms, allowing the distribution of entanglement across the network and the teleportation of quantum states between nodes.

The quantum internet

Meeting the Universe Halfway is an ambitious book with far-reaching implications for numerous fields in the natural sciences, social sciences, and humanities. In this volume, Karen Barad, theoretical physicist and feminist theorist, elaborates her theory of agential realism. Offering an account of the world as a whole rather than as composed of separate natural and social realms, agential realism is at once a new epistemology, ontology, and ethics. The starting point for Barad’s analysis is the philosophical framework of quantum physicist Niels Bohr. Barad extends and partially revises Bohr’s philosophical views in light of current scholarship in physics, science studies, and the philosophy of science as well as feminist, poststructuralist, and other critical social theories. In the process, she significantly reworks understandings of space, time, matter, causality, agency, subjectivity, and objectivity.

In an agential realist account, the world is made of entanglements of “social” and “natural” agencies, where the distinction between the two emerges out of specific intra-actions. Intra-activity is an inexhaustible dynamism that configures and reconfigures relations of space-time-matter. In explaining intra-activity, Barad reveals questions about how nature and culture interact and change over time to be fundamentally misguided. And she reframes understanding of the nature of scientific and political practices and their “interrelationship.” Thus she pays particular attention to the responsible practice of science, and she emphasizes changes in the understanding of political practices, critically reworking Judith Butler’s influential theory of performativity. Finally, Barad uses agential realism to produce a new interpretation of quantum physics, demonstrating that agential realism is more than a means of reflecting on science; it can be used to actually do science.

Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning

In the past years the laser has become a successful tool for the investigation of collision-induced energy transfer processes in molecules [1,2]. This energy transfer can occur between vibrational levels (V-V process) or between the vibrational and the translational/rotational degrees of freedom (V-T/R process). In general the V-V transfer is very fast compared to V-T/R relaxation. Therefore, especially in organic molecules, rather short V-V relaxation times may be expected [3]. In the experiment described here V-V transfer in ethylene has been measured using the laser-fluorescence method.

Vibrational Relaxation of Ethylene Excited with a Parametric Oscillator

Atomic coherence initiated noise free energy transfer in a resonant medium

Ozone profiles are compared which were obtained by two entirely different techniques during the MAP/Globus campaign in September 1983. At Hohenpeissenberg (48° N, 11° 0) seventeen Brewer/Mast sondes were launched. These chemical sondes can reach altitudes up to 35 km. About 40 km apart, on top of Zugspitze (47.5° N, 11° 0) a laser radar system was measuring the ozone concentration up to altitudes of 50 km. The weather situation in September 1983 allowed the laser radar to be in operation for sixteen nights, so that a detailed comparison between both methods could be performed.

Intercomparison of Ozone Profiles Obtained by Brewer/Mast Sondes and Differential Absorption Laser Radar

The investigation of the resonance fluorescence induced by monochromatic laser radiation has received large attention in recent years. A review of level crossing experiments performed under those conditions has been given. Furthermore experiments in which the frequency distribution of the resonance radiation was analysed using a Fabry-Perot interferometer have been discussed as well as correlation experiments now under way.

Atomic fluorescence under monochromatic excitation

An extremely thin cell with smoothly variable thickness of Rb atomic vapor column in the range 140-1700 nm has been developed. New possible applications for laser spectroscopy are presented.

Herbert Walther

Papers

Vibrational Relaxation of Ethylene Excited with a Parametric Oscillator

Atomic coherence initiated noise free energy transfer in a resonant medium

Intercomparison of Ozone Profiles Obtained by Brewer/Mast Sondes and Differential Absorption Laser Radar

Atomic fluorescence under monochromatic excitation

Extremely thin cell for laser spectroscopy with smoothly variable thickness of atomic vapor column in the range 140-1700 nm