Jobs – Page 206 of 521

CAST: enlightening the dark

Giovanni Cantatore and Marin Karuza in front of the CAST magnet, holding the heart of the KWISP force sensor: nanomembranes to detect the direct coupling of exotic particles to matter.
Image credit: Luca Nagel/CAST.

Our star has been the target of human investigation since the beginning of science. However, a plethora of observations are not yet understood. A good example is the unnaturally hot solar corona, the temperature of which spans 1–10 MK. This anomaly has been studied since 1939 but, in spite of a tremendous number of observations, no real progress in understanding its origin has been made. We also know that a significant fraction of the Sun’s total luminosity, about 4%, can escape as some form of radiation that we do not yet know, without being in conflict with the constraints imposed by the evolution of the Sun. In this framework, physicists have hypothesised the existence of exotic particles, including axions and chameleons. Other particles, such as the celebrated WIMPs, also point to the Sun as a target for relevant investigations. Indeed, over cosmic time periods, WIMPs can be gravitationally trapped inside the solar core. There, they condense, allowing their mutual annihilation into known particles, including escaping high-energy neutrinos.

A breakthrough discovery in the so-called “dark sector” could pop up at any time. The question is when this will happen and where: in an Earth-bound laboratory or in a space-bound one. It is worth stressing that it is not at all obvious whether the extreme conditions in the Sun can be completely duplicated on Earth.

Benchmark for axion searches

For many days in recent years, CAST – the CERN Axion Solar Telescope (CERN Courier April 2010 p22) – has pointed its antenna towards the Sun for about 100 minutes during sunrise and sunset. Its aim was to detect solar axions through the Primakoff effect (1950), a classic detection scheme from particle physics. This solar-axion search was completed in November 2015 (CERN Bulletin, https://cds.cern.ch/journal/CERNBulletin/2015/39/News%20Articles/2053133?ln=en), and even though CAST has not observed an axion signature, it provides world-best limits on the axion interaction strength with normal matter in the form of the magnetic field present inside the CAST magnet bores.

Axions from the Big Bang can convert into microwaves inside these resonant cavities, which are inserted into the bores of the CAST magnet and immersed in its 9.6 T dipole field.
Image credit: CAPP, Korea.

The results of the CAST scientific programme were also achieved thanks to the X-ray telescope (XRT) recovered from the ABRIXAS German space mission and installed downstream on one of the magnet bores. The telescope works as a lens focusing the photon flux onto the detector. Any increase in the signal-to-noise ratio would be a signature of axions. This unique technique, borrowed from astrophysics, allowed the collaboration to simultaneously measure signal and background. Given its success, a second X-ray telescope was added in 2014.

Very accurate tracking of the Sun is crucial to the experiment’s data analysis. To provide this, CERN surveyors pinpoint exactly where the telescope lies and where it is pointing to, relative to a reference in time and space. However, to be absolutely certain, twice a year, when the Sun is visible through a window in the CAST experimental hall, the magnet tracks the Sun with a camera mounted and aligned to point exactly along its axis. This process of “Sun filming” has confirmed that CAST is pointing at the centre of the Sun with sufficient precision.

Up to now, CAST has been looking for exotica that the Sun might have produced some 10 minutes earlier. However, thanks to a continuous upgrade programme for the detectors and the development of new ideas, the collaboration is now extending its horizons, back in time closer to the Big Bang and into the dark sector. In its 119th meeting, the CERN SPS and PS experiments Committee (SPSC) recommended the new CAST physics programme for approval, which includes searches for relic axions and chameleons.

Axions from the Big Bang

Due to their extremely long lifetime (longer than the age of the universe), axions produced during the Big Bang could still be detected today. These relic particles have been searched for with instruments using a resonant cavity immersed in a strong magnetic field where axions are expected to convert into photons (with a probability that depends quadratically on the magnetic-field intensity). The signal is further enhanced when the cavity is at resonance with the photon frequency. In particular, the signal strength depends on the cavity “quality factor”, defined as the ratio between the cavity fundamental frequency and the resonance line width.

However, the inherent problem of axion searches is the unknown rest mass, although the cosmologically preferred mass range for the so-called cold dark-matter axions lies between μeV/c² and meV/c², with a favoured region around 0.1 meV. The photon energy is equal to the axion rest mass, because its kinetic energy is negligibly small. To scan the regions of interest, the cavity resonant frequency is varied over a certain axion-mass range, basically determined by cavity size and shape.

Artist’s view of the KWISP force-sensor principle. An optical Fabry–Pérot resonator senses the movements of a nanomembrane, which like a sail, catches the wind of chameleons from the Sun.
Image credit: Giovanni Cantatore.

Dipole magnets, such as the CAST magnet, can be transformed into relic axion antennas by means of new resonant microwave cavities. These cavities, designed and built by the Korean Centre for Axion and Precision Physics (CAPP) in collaboration with CERN, will be inserted inside the dipole magnetic field within the 1.7 K cold bores to search for microwave photons converted from cosmological axions, which would be direct messengers from the Big Bang era. In addition, a second microwave sensor will be inserted in the other bore. With its new set-up currently under construction, CAST should have access to an axion-mass range up to 100 μeV/c². At these relatively high mass values, detection becomes much harder, but the hope is that this region, which is critical for the dark-matter conundrum, will also be explored.

Chameleons come on stage

As may be imagined, detecting chameleons – new scalar particles that are possible candidates for the unknown dark energy – is not a trivial matter. The CAST collaboration plans to do it by exploiting two different couplings: Primakoff coupling to photons and direct coupling to matter.

The expected energy spectrum of solar chameleons has a peak at about 600 eV, making it even harder to detect them through their Primakoff coupling than the axions. Therefore, sub-keV threshold, low-background photon detectors are required. To tackle this problem, the CAST collaboration decided to start with a Silicon Drift Detector (SDD), becoming, with recently published results, the first chameleon helioscope. The new InGRID detector, based on the MicroMegas concept and having on-board read-out electronics, replaced the CCD camera in the XRT focal plane in 2014, improving the overall expected performance of CAST for solar chameleons.

Chameleon particles are theorised to have amazing properties: they can freely traverse thick slabs of dense matter if they impinge on them normally (i.e. perpendicular to), or they can bounce off nanometre-thin membranes, not much denser than ordinary glass, when approaching them at a grazing incidence angle of just a few degrees. In doing so, they exert a minute force, much like grains of sand hitting the palm of a hand. If detected, this tiny force is the signature of the direct interaction of chameleons with matter.

Forces are experienced in everyday life, so there may seem to be nothing special about detecting them. However, sensing exceedingly tiny forces requires advanced skills and techniques. The KWISP opto-mechanical force sensor is able to instantaneously feel forces of 10^–14 N – that is, the weight of a single bacterium. It uses a Si₃N₄ membrane, just 100 nm thick, to intercept the flux of solar chameleons. Being as elastic as a drumhead, it flexes under their collective force (pressure) by an amount less than the size of an atomic nucleus. The membrane sits inside a Fabry–Pérot optical resonator, made of two high-reflectivity super mirrors facing each other, where a standing wave from an IR laser beam is trapped. As the membrane flexes, the characteristic frequency of this wave changes, generating the signal. The power of the KWISP sensor comes from the combined response of two high-Q resonators, the optical (Fabry–Perot) and the mechanical (membrane).

In addition to KWISP, a further ingredient is necessary in the search for chameleons: a time-dependent amplitude modulation on the chameleon flux in such a way as to beat the drum at its eigenfrequency for maximum effect. To solve this problem, the authors have invented the chameleon chopper, which is basically a rotating optically flat surface, applying the principle of chameleon optics: transmission at normal incidence, reflection at grazing incidence. Surprisingly, phase-locking techniques can also exploit this angular variation to obtain additional information on chameleon physics.

According to theory, the internal surfaces of the ABRIXAS telescope, designed to reflect X-rays impinging at grazing incidence, would also reflect and focus chameleons. This increases their flux by a factor larger than 100, which is further enhanced by the exposure time gained from Sun-tracking. This unplanned ability of the X-ray telescope is one of those lucky events by which nature sometimes smiles at scientists, allowing them to explore its secrets.

The KWISP prototype is currently taking data at INFN Trieste (Italy) and a clone is being commissioned at CERN to take advantage of the CAST infrastructure. As mentioned also by the SPSC referees, with the force-sensor KWISP, it should be possible to address more fundamental physics questions, such as quantum gravity or the validity of Newton’s 1/R² law at short distances. We plan, with colleagues from the Technical University in Darmstadt (Germany), Freiburg University (Germany) and CAPP (Korea), to develop an advanced KWISP design, aKWISP, and we welcome the interest of additional collaborators.

While it remains one of the lowest-cost astroparticle physics experiments, CAST is preparing to leap further into the dark sector. As history teaches us (see table 1), the Sun may be the key to this, although as our understanding of the Sun deepens, we will most probably uncover more mysteries about the star that gives us life.

• For more information, see https://cds.cern.ch/record/2022893.

Imaging science: physics laboratories under the spotlight

Image credit: Molly Patton/Laboratory: SUPL, Australia.

“Lighting the way for dark-matter detection and future particle-physics research.” An electric mining drill deep within the Stawell Gold Mine (SUPL). Awarded 1st people’s choice.

Image credit: Robert Hradil/Laboratory: CERN, Switzerland.

“The Incredibles.” This photograph was taken in the CERN restaurant, one of the key meeting points for CERN scientists. The jury noted the humanity behind the image: “There is a need for transferring ideas to make and create the world we live in.” Awarded 3rd jury’s choice.

Image credit: Katy Mackenzie/Laboratory: TRIUMF, Canada.

From TRIUMF’s main control room, operators control the laboratory’s main cyclotron and proton beamlines. The jury noted the technical complexity of the science with the emotional component of the human operator. Awarded 1st jury’s choice.

Image credit: Pietromassimo Pasqui/Laboratory: INFN, Italy.

A vacuum chamber containing a mirror carrying the FLAME laser beam to the experimental room of the SPARC accelerator at the INFN National Laboratory of Frascati. Awarded 2nd people’s choice.

Image credit: Rosemary Wilson / Laboratory: DESY, Germany.

Detail of the forward radial wire chamber forming part of the H1 detector that took data at the HERA collider at DESY from 1992 to 2007. Awarded 3rd people’s choice.

Image credit: Mark Killmer/Laboratory: SUPL, Australia.

Taken in the temporary laboratory set up in the Stawell Gold Mine at SUPL, the image “gives a sense of the work that goes into particle physics long before there are data to analyse”. Awarded 2nd jury’s choice.

PS beam extraction becomes more efficient

Résumé

L’extraction des faisceaux du PS devient plus efficace

Depuis septembre 2015, les faisceaux de protons utilisés pour les expériences de physique avec cible fixe auprès du Supersynchrotron à protons du CERN sont produits par un nouveau système d’extraction à partir du Synchrotron à protons. Ce système, plus efficace, est appelé système d’extraction multitours (MTE). Les tests ayant été probants dans l’ensemble, le MTE sera, en 2016, le mode d’extraction standard pour l’exploitation avec cible fixe auprès du SPS. D’ici le milieu de l’année prochaine, une décision définitive sera prise sur le futur à long terme du MTE.

Fig. 1. Measurements of the beam profiles after splitting (top) and the corresponding beam spills after extraction, as measured in the transfer line (centre). The correlation between the oscillations in the MTE efficiency and the 5 kHz line of the PFW current is also shown (bottom).
Image credit: CERN.

First thought of in 2002 with the goal of significantly reducing beam losses that cause high ring activation, the Multi-Turn Extraction (MTE) system (CERN Courier March 2009 p29) has, since then, encountered numerous challenges during its implementation in the Proton Synchrotron (PS). Now, the regular MTE operation over the last two months constitutes a crucial milestone for this new beam manipulation, and paves the way for further studies and optimisations.

The lows

In 2010, MTE was the default choice to deliver beam for the Super Proton Synchrotron (SPS) physics run. However, after only a few weeks of operation for the production of neutrinos in the framework of the CNGS programme, the PS extraction mode had to revert back to Continuous-Transfer (CT) extraction, which is associated with high beam losses along the ring circumference. This feature was the reason for studying an alternative extraction mode. In the new scheme, the beam is split horizontally into five beamlets – one in the centre and four in stable islands of the horizontal phase space. Unfortunately, the intensity sharing between the islands and the centre (figure 1) and the extraction trajectories were fluctuating on a cycle-to-cycle basis. This was not only significantly affecting the beam transmission through acceleration in the SPS, but also prevented proper optimisation of the SPS parameters. In addition, activation of the PS extraction region had increased anomalously, although the rest of the ring was profiting from a significant reduction in radiation levels with respect to CT operation.

Intense investigations were undertaken to find the source of the observed variations and to overcome the PS ring activation. The latter problem proved to be much easier to solve than the former.

Fig. 2. Time evolution of the MTE efficiency (left) and the resulting distribution (right). The MTE efficiency is defined as the average of the beam intensity of each of the first four extracted turns normalised to the total beam intensity: I_island/I_tot. Minimum and target efficiencies as requested by the SPS are also shown.
Image credit: CERN.

The increased activation was tackled by designing a new piece of hardware, a so-called dummy septum, which is a passive septum with only a copper blade and no coils for generating a guiding magnetic field. The dummy septum is supposed to intercept protons from the de-bunched beam during the extraction-kickers’ rise time, therefore preventing them from interacting with the blade of the active extraction septum. This approach, combined with appropriate shielding of the dummy septum, provides a well-localised loss point that is acceptable in terms of overall activation of the PS ring. It is worth noting that the use of a shadowing device for the main extraction septum is a known approach in, for example, the SPS. However, in a small ring like the PS, the two devices cannot easily be located next to each other, which makes the overall configuration more complicated in terms of beam dynamics.

A side effect of the implementation of the dummy-septum solution is that the horizontal aperture of the PS ring is reduced, which calls for a complete review of all PS fast-extraction schemes to make them compatible with the presence of the dummy septum. This additional hurdle was overcome and the proposed solution looked acceptable on paper.

During Long Shutdown 1 (February 2013–May 2014) the design, construction, and installation of the dummy septum was completed, together with some modifications to the powering of the extraction bump. The beam commissioning of the whole system, including the new extractions, was completed successfully by the end of 2014.

To tackle the fluctuations of the extraction trajectories, systematic observations of hardware parameters in the PS ring, such as the currents of the key magnetic elements controlling the machine configuration, were undertaken. The aim was to find a correlation with the changes in intensity sharing between beamlets. Despite the long and detailed observations, no evidence for the guilty element was found, and the sources of fluctuations remained unidentified.

The highs

Activities to track down the origin of the fluctuations in the intensity sharing and of the extraction trajectories of the MTE beam resumed at the beginning of the 2015 physics run. Eventually, it was possible to identify a correlation between these variations and the amplitude of a 5 kHz ripple present on the current of some special circuits located in the PS main magnets (figure 1). The PS ring is made up of 100 combined-function main magnets with additional coils installed on the magnets’ poles. These so-called pole-face windings (PFWs) and figure-of-eight loops allow control of the working point in terms of tunes and linear chromaticities, and some higher-order parameters such as the second-order chromaticity. The ensemble of the electrical circuits present in the main magnets and the interaction between the various components is extremely complex; all switching-mode power converters feature a ripple at 5 kHz with a varying phase, which turned out to be the culprit of the observed fluctuations.

Fig. 3. Variation over time of the beam intensity (blue dots) and of the extraction efficiency (red dots) in the PS.
Image credit: CERN.

This crucial observation guided the power-converter experts to implement mitigation measures (additional inductances to filter the ripple amplitude), and their expected effect was immediately observed as improvement of the stability of the MTE beam parameters (figure 2).

This milestone again opened up the route to transfer to the SPS, and first tests of beam delivery were conducted in the summer of 2015. Their success accelerated the subsequent steps, which culminated in the decision to use MTE for fixed-target physics: after the low of 2010, MTE was back in business.

Of course, this was just the start rather than the end of efforts. The studies, which were conducted on both the PS and SPS rings, continued in view of improving the overall beam quality. The intensity was raised from an initial value of about 1.6 × 10¹³ protons extracted from the PS to about 2.0 × 10¹³ protons at the end of the run, with extraction efficiency in the PS around 98% (figure 3).

By the end of the run, the PS Booster joined the challenge, managing to produce brighter beams in the vertical plane to improve SPS transmission, which is plagued by limitation of the vertical aperture. The final touch was the finalisation of the dummy-septum configuration.

Promising future

The progress and future of MTE were discussed in two internal reviews in 2015. Given the overall success of the MTE studies, commissioning and operation during the last part of the physics run, MTE will be the standard extraction mode for the 2016 fixed-target run at the SPS. This is a necessary step to acquire better knowledge of the new beam manipulation, and also understand the limitations coming from the existing hardware. In parallel, studies to probe the beam behaviour for even higher intensities will be carried out. This is important in view of future projects requiring even more intense beams than those delivered today. By the middle of next year, a firm decision concerning the long-term future of MTE and its predecessor CT will be taken.

• For all MTE-related documents (design report, publications and talks), visit ab-project-mte.web.cern.ch/AB-Project-MTE/Documents.html.

Science: a model for collaboration?

CERN’s seat at the United Nations General Assembly. CERN was granted the status of Observer in 2012.
Image credit: Maurizio Bona/CERN.

Today, science, technology and innovation are among the most powerful forces driving social change and development. However, what is the actual role that a fundamental science laboratory like CERN can have when it comes to designing creative strategies to strengthen public goods in society?

With a view to contribute to the realisation of the 2030 Agenda for Sustainable Development, which was approved in September by the United Nations Member States, the United Nations Office at Geneva (UNOG) hosted a one-day symposium organised in collaboration with CERN and with the support of Switzerland and France, in their capacity as CERN host states.

Air, water, biodiversity, education, knowledge, access to the Internet, peace and welfare: these public goods can be preserved only with the involvement of all stakeholders. At the event, policy makers, diplomats, ambassadors, scientists, intellectuals, epistemic associations, representatives of international governmental and non-governmental organisations, and civil-society representatives explored the value of CERN as a model for co-operation.

CERN is a recognised example of peaceful international collaboration based on transparency, openness and inclusion. The invention of the World Wide Web is emblematic of the spirit that drives advances in basic science, which enable open innovation and education, and connect the worldwide community through shared values. A typical scientific community is self-organised and able to share the infrastructure needed by all. The centrality of knowledge (scientific arguments in global policy), long-term thinking, agile project and risk management, even under harsh conditions of unpredictability, smart governance and social networking, big data, considering alternative scenarios – these are all features and “goods” that belong to the scientific world but that also play a role in different contexts.

Necessary compromises

The UN world has an impressive infrastructure that ensures global governance, including the UN Secretariat, the General Assembly and the Economic and Social Council. These structures permitted a global consultation process that led to the formulation and adoption of the 2030 agenda, with its 17 sustainable-development goals and 169 targets. The complexity of the governance of such an important process is the result of necessary compromises. It is everybody’s duty to make it efficient and capable of addressing the difficult global challenges the world is now facing. CERN can contribute by explaining its functioning model and by providing, when needed, direct input on science, technology and education.

About one week after the symposium at UNOG, CERN and the World Academy of Arts and Sciences (WAAS) hosted another one-day conference to discuss the topic of “Science, technology, innovation and social responsibility”. The event was organised under the auspices of UNOG and saw the participation of the EPS and some Geneva-based international organisations, including the International Labour Office (ILO), World Health Organization (WHO), United Nations Institute for Training and Research (UNITAR), World Meteorological Organization (WMO), International Organization for Standardization (ISO) and World Intellectual Property Organization (WIPO). The specific objective was to survey the potential impact of scientific and technological innovation in different fields on the progress of humanity, independent of political boundaries or limits, whether spiritual or physical.

Lively discussions took place around the topic of social responsibility that comes with self-governance of the scientific community. Obviously, this is of particular relevance when it comes to dealing with health-related issues. In particular, fighting certain types of disease requires a strong collaboration between the scientific community, governments and companies producing vaccines. But scientific and technological developments also have a huge impact on the labour market. In this respect, science and society are not sufficiently synchronised, and future planning needs to be better co-ordinated. In fields such as meteorology, scientific co-operation is accepted as essential, because without it every country would lose: predictions and warnings are possible only with global exchange of data.

All of these initiatives show the importance of keeping the dialogue between scientists, diplomats, policy makers, business experts and the public at large constantly alive. Since the very beginning of the scientific venture that gave birth to CERN, people from different cultures, religions and political opinions could speak the common language of science. In this scenario, peace appears as a natural consequence and becomes an attitude. More than 60 years of peaceful and fruitful collaboration are the tangible result that science can indeed serve as a successful model to follow.

A video recording of “The CERN model, United Nations and Global Public Goods: addressing global challenges” is available at webtv.un.org/watch/panel-1-the-cern-model-science-education-and-global-public-good-cern-unog-symposium-2015/4590293913001. A video recording of the “Science, technology, innovation and social responsibility” conference is available at cds.cern.ch/record/2103652.

From the Great Wall to the Great Collider: China and the Quest to Uncover the Inner Workings of the Universe

By S Nadis and S T Yau
International Press of Boston

The volume presents the reasons behind the ambitious project pursued by a group of distinguished Chinese scientists, led by Shing-Tung Yau, professor of mathematics and physics at Harvard University, to build the next biggest particle collider in China, to continue the quest to identify the fundamental building blocks of nature.

The discovery of the Brout–Englert–Higgs boson put in place the long-sought-after missing piece of the Standard Model of particle physics. Although this model can describe the behaviour of particles with remarkable accuracy, it is actually incomplete, because it is not able to explain a range of phenomena.

Several centuries ago, Chinese emperors erected a majestic ring of fortification – the Great Wall. Today, Chinese researchers are contributing to particle physics with a project of almost comparable magnificence: the building of a giant accelerator, the Great Collider.

The book explains the scientific issues at stake, discusses the history of particle physics, and tells the story of the birth and development of the Great Collider project.

Inflation and String Theory

By D Baumann and L McAllister Cambridge University Press

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This complete and accessible text, written by two of the leading researchers in the field, provides a modern treatment of inflationary cosmology and its connection to string theory and elementary particle theory.

The past two decades of advances in observational cosmology have brought about a revolution in our understanding of the universe. In particular, deeper studies of the cosmic microwave background have revealed strong evidence for a period of inflationary expansion in the very early universe. At the same time, new developments in string theory have led to a better understanding of inflation in a framework that unifies quantum mechanics and general relativity.

After a brief introduction about observations in favour of the inflationary hypothesis, the volume provides an overview of effective field theory, string theory, and string compactifications. Finally, several classes of models of inflation in string theory are examined in detail.

The background material in geometry and cosmological perturbation theory included in the appendices makes the book self-contained and accessible not only to experienced researchers, but also to graduate students and readers who are new to the field.

Nuclear and Particle Physics

By Claude Amsler
IOP Publishing

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This textbook provides an introductory course on nuclear and particle physics for undergraduate and early graduate students. It originated from a series of lectures given at the Physics Institute of the University of Zurich by the author. The subjects are presented following their historical development. The explanations are experimentally and phenomenologically orientated, and often make use of intuitive arguments. In addition, many concepts and phenomena are derived with inductive rather than deductive thinking.

Originally published in German, this new version in English has been enriched with several modern topics, such as the Higgs boson, updates on neutrinos, the top quark and bottom-quark physics.

Supersymmetric Field Theories: Geometric Structures and Dualities

By Sergio Cecotti
Cambridge University Press

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An unconventional and elegant geometrical approach is adopted in this book to explain supersymmetric field theories, and describe intuitive methods for understanding the logic underlying such concepts. Aimed at graduate students and researchers, the collection of lectures provides an advanced course in supergravity and supersymmetry, which requires knowledge of the basic concepts and fundamental tools of these fields. The author shows how complex results and formulae obtained from the more classical approaches to SUSY can be simplified dramatically when translated to a geometric setting.

Covering a wide range of topics and offering rigorous, in-depth explanations, this text would be an extremely valuable resource for theoretical physicists.

Particle and Astroparticle Physics, Gravitation and Cosmology: Predictions, Observation and New Projects – Proceedings of the XXXth

International Workshop on High Energy Physics
By V Petrov and R Ryutin (eds)
World Scientific

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The most interesting talks delivered at the XXXth International Workshop on High Energy Physics, held in Protvino, Russia, in June 2014, are collected in this volume, along with the minutes of the six panel discussions. As the full title suggests, this conference not only focused on high-energy physics, but addressed a wide range of fundamental issues of modern particle and astroparticle physics, gravitation and cosmology.

The major subjects presented included the discovery and interpretation of the Brout–Englert–Higgs boson at the LHC, heavy-quark physics, quark–gluon plasma studies, diffractive scattering at high energies, neutrino oscillations, and theoretical interpretations of cosmological data on the evolution of the universe.

The panel discussions, in turn, highlighted difficult points in the various domains of modern physics, and identified possible research paths.

General Relativity and Gravitation: A Centennial Perspective

By A Ashtekar et al (eds)
Cambridge University Press

On the occasion of the centennial of Einstein’s discovery of general relativity, the International Society on General Relativity and Gravitation commissioned a team of leading international researchers to write about the advances that have occurred in all of the branches of physics during the last three decades. Through 12 comprehensive chapters, the volume gives an overview of key topics in relativistic astrophysics, cosmology and gravitational-wave theories, as well as mathematics and computational science. The book in intended both for beginners, who could use it as an introduction to the entire field, and for more advanced researchers, especially if they are interested in subjects that are outside of their field of expertise. Organised in four parts, each of about five chapters, the book guides the reader on a journey from the triumph of Einstein’s theory of relativity through the phenomenon of gravitational waves, to quantum gravity.

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