# GRG Editor’s Choice: recent highlight articles

In each volume of the journal General Relativity and Gravitation (GRG), a few papers are marked as “Editor’s Choice”. The primary criteria is original, high-quality research that is of wide interest within the community. These recent articles deserves special attention:

Abraham I. Harte,
“Gravitational lensing beyond geometric optics: II. Metric independence”,
Gen Relativ Gravit (2019) 51: 160.
https://doi.org/10.1007/s10714-019-2646-7

“Causal geodesic incompleteness of spacetimes arising from IMP gluing”,
Gen Relativ Gravit (2019) 51: 139.
https://doi.org/10.1007/s10714-019-2621-3

Please, browse all Editor’s Choice articles at:
https://www.springer.com/gp/livingreviews/relativity/grg-editors-choice

Frank Schulz
Publishing Editor GRG

# Giulio Rampa PhD Thesis Prize, Call for nominations, 2020 Edition

Giulio Rampa PhD Thesis Prize for Outstanding Research in General Relativity and Gravitational Physics 2020 Edition

Call for nominations

A graduate of the University of Pavia, Giulio Rampa, in his short life, had a profound impact on his fellow students and the faculty of the Department of Physics of the University of Pavia. Following his Master in Physics, he soon entered The Graduate School at the Max Planck Institute for Gravitational Physics, (Albert Einstein Institute), Potsdam where he became deeply interested in general relativity. Known for his remarkable personality, as well as for his outstanding intellectual potential, Giulio Rampa’s life is celebrated through this prize honouring an outstanding PhD Thesis in general relativity or gravitational physics.

A monetary prize of 2,000 EUR will be awarded every two years to a graduate student for outstanding research on all aspects of general relativity or gravitational physics. The prize has been established in 2011, and is endowed under the terms of a donation from Nadia and Giorgio Rampa. Any PhD student who graduated in a University or research centre worldwide defending a PhD Thesis on all aspects of general relativity or gravitational physics between January 1st 2018 and December 31st 2019 is eligible to be nominated for this prize.

The nominator should submit – preferably via email – all relevant material described below to the following address:

Secretariat of The Rampa Prize Committee,
c/o Department of Physics,
Via Bassi 6, 27100 Pavia, Italy
e-mail: rampa.prize[AT]pv.infn.it

The candidature material should comprise: 1) a one-page abstract of the PhD Thesis; 2) a full copy of the PhD Thesis; 3) a letter of recommendation from the Thesis Advisor; 4) one or more letters of endorsement – possibly from the Thesis reader – substantiating the candidate’s contributions; 5) a complete CV. All of the material should be submitted no later than March 31st, 2020. Self-nominations will not be accepted.

The following criteria are reviewed when selecting the Giulio Rampa prize recipient: (i) Originality of Contribution; (ii) Breadth of Work; (iii) Publications; (iv) Quality of Nomination; (v) Quality of Endorsement.

The recipients of the prize are to be selected by a committee of international experts whose resolution will be communicated to the winners by June the 30th, 2020.

The prizes will be presented at the 24th edition of the “Italian Society for General Relativity and Gravitation (SIGRAV) Conference” to be held in September 2020. This is the biennial Conference of the Italian Society for General Relativity and Gravitation (SIGRAV) devoted to all aspects of gravitational physics. The Rampa Prize-winner will have the opportunity to present his/her work during a special session of the conference. The winner will also be announced during the annual Honours Ceremony during the Inauguration of the Graduate Studies Academic Year in Pavia, in December 2020.

Previous Awardees:

2012 Thomas-Paul Hack
2016 not assigned
2018 Davide Gerosa, Jan Ostrowski

# GRG Topical Collection “Testing the Kerr spacetime with gravitational-wave and electromagnetic observations”

We are please to inform you that the Topical Collection on “Testing the Kerr spacetime with gravitational-wave and electromagnetic observations”, edited by Emanuele Berti, has been completed and is free-to-read until 11 December 2019.

One of the Holy Grails of observational astronomy is to confirm the prediction that black holes in the Universe are described by the Kerr solution of Einstein’s field equations of general relativity. This Topical Collection provides a status report of theoretical and experimental progress towards confirming the “Kerr paradigm” through X-ray astronomy, gravitational lensing, stellar tidal disruption events, superradiance, and gravitational-wave observations of black hole binary mergers.

Berti, E.: Topical collection: Testing the Kerr spacetime with gravitational-wave and electromagnetic observations (EDITORIAL), Gen. Relativ. Gravit. 51(11), 140 (2019).
https://doi.org/10.1007/s10714-019-2622-2

We hope that you will publish your next article in GRG and look forward to working with you soon!

# Open Session of the Chalonge De Vega School, Paris, France

Ecole Internationale d’Astrophysique Daniel Chalonge – Hector de Vega

International School of Astrofundamental Physics Daniel Chalonge – Hector de Vega

Open Session “Last Cosmic News, Highlights and Prospects”

Thursday, November 28, 2019 – 2:15 pm

at the House of Argentina, 27A blvd Jourdan, Cite’ Internationale
Universitaire of Paris, 75014 Paris

In the Program:

-The Cosmo-Physics at the Chalonge-de Vega School and the Nobel Prize of Physics 2019, by Professor Norma SANCHEZ, CNRS-OP-PSL-SU, Paris

-News of the Cosmological Standard Model: Pre-inflation, H_0 and
Dark Energy

-LiteBIRD, Millimetron, CMB, “White Papers” ….

-Road of new ideas and their associated language: Ideo-Semantics of Time in Cosmology, by Dr Helios JAIME, Paris Sorbonne.

-The Cosmology in the work of Italo Calvino in Paris and ” the circle of Oulipo”, by Dr Alba ZANINI, INFN-Turin, president of Kores, with the special participation of Sara D’AMARIO actress and Francois-Xavier FRANTZ director scene.

– “And that is not all ….” (quote from Henri Poincare). Continue on November 28th …

-Announcement and information:
https://www.obspm.fr/ecole-internationale-d-4159.html

-Poster and programme:
https://chalonge-devega.fr/Programme2019.html

Brochure and invitation:
https://chalonge-devega.fr/invitation28novembre2019.pdf

With compliments and kind regards

Prof Dr Norma G. Sanchez and the Chalonge – de Vega School

https://chalonge-devega.fr/
https://chalonge-devega.fr/HdeV.html
https://chalonge-devega.fr/sanchez/

2020: 30 pioneering years of the Chalonge-de Vega School: research,
prospective, training and scientific culture at the forefront of cosmofundamental physics
——————————————————————————-

# The Nineteenth Release of the Einstein Toolkit

Release Announcement

We are pleased to announce the nineteenth release (code name “Mayer”) of the Einstein Toolkit, an open, community developed software infrastructure for relativistic astrophysics. The highlights of this release are:

A new thorn has been added:

* FishboneMoncriefID

Also, for the first time, a new code has been added.

* SelfForce-1D

The ETK is embracing a new model of assigning credit: Until now, the 2012 Einstein Toolkit paper was the common way to cite the Einstein Toolkit (though we suggested citing the website itself). In this release, however, we will begin using https://doi.org/10.5281/zenodo.3522086 to recognize the many contributers that have worked on the toolkit since that time.

In principle, the Einstein Toolkit was always intended to be a collection of codes for exploring numerical relativity, not simply a collection of arrangements and thorns for the Cactus Framework. Going forward, SelfForce-1D will have regular releases using the same release tags as the Cactus-based codes, and will have a similar setup for the running of test-suites. While the new code will not download at the same time as the Cactus-based code, download instructions will appear in the same places.

In addition, bug fixes accumulated since the previous release in March 2019 have been included.

The Einstein Toolkit is a collection of software components and tools for simulating and analyzing general relativistic astrophysical systems that builds on numerous software efforts in the numerical relativity community including the spacetime evolution codes McLachlan and Lean, analysis codes to compute horizon characteristics and gravitational waves, the Carpet AMR infrastructure, and the relativistic magneto-hydrodynamics codes GRHydro and IllinoisGRMHD. For parts of the toolkit, the Cactus Framework is used as the underlying computational infrastructure providing large-scale parallelization, general computational components, and a model for collaborative, portable code development.

The Einstein Toolkit uses a distributed software model and its different modules are developed, distributed, and supported either by the core team of Einstein Toolkit Maintainers, or by individual groups. Where modules are provided by external groups, the Einstein Toolkit Maintainers provide quality control for modules for inclusion in the toolkit and help coordinate support. The Einstein Toolkit Maintainers currently involve postdocs and faculty from six different institutions, and host weekly meetings that are open for anyone to join in.

Guiding principles for the design and implementation of the toolkit include: open, community-driven software development; well thought-out and stable interfaces; separation of physics software from computational science infrastructure; provision of complete working production code; training and education for a new generation of researchers.

The Einstein Toolkit is primarily supported by NSF 1550551/1550461/1550436/1550514 (Einstein Toolkit Community Integration and Data Exploration).

The Einstein Toolkit contains about 400 regression test cases. On a large portion of the tested machines, almost all of these tests pass, using both MPI and OpenMP parallelization.

The changes between this and the previous release include:

Larger changes since last release

* The Fishbone Moncrief Initial Data thorn (FishboneMoncriefID) thorn has been added to the WVUThorns arrangement
– This thorn solves the equations originally posed by Fishbone & Moncrief, describing a non-self-gravitating equilibrium disk of matter orbiting a spinning black hole in standard (spherical) Kerr-Schild coordinates. When the disk is seeded with initially dynamically unimportant poloidal magnetic fields, dramatic magnetic instabilities occur during the subsequent evolution, launching ultrarelativistic jets. Thus the Fishbone-Moncrief solution provides a standard testbed for GRMHD accretion disk codes.
– From a code perspective, FishboneMoncriefID is notable in that it is the first ETK thorn entirely written and documented within pedagogical Jupyter notebooks. In these notebooks, the Fishbone-Moncrief equations are converted from Einstein-like notation into optimized C code using NRPy+, a Kranc analogue depending only on Python and its open-source SymPy computer algebra software.
* The inclusion of the SelfForce-1D code in the Einstein Toolkit as the first non-Cactus code in the toolkit.
– Evolves the sourced scalar wave equation on a Schwarzschild spacetime using the effective source approach to point particles.
– The wave equation is decomposed into spherical harmonics and the resulting 1+1 dimensional equations are discretized in the radial direction using the discontinuous Galerkin method.
* Update hwloc to 1.11.12
* Groups of vectors of vectors are now handled properly by RotatingSymmetry90 and RotatingSymmetry180
* Compilation of PAPI is faster and produces fewer warnings

How to upgrade from Proca (ET_2019_03)

To upgrade from the previous release, use GetComponents with the new thornlist to check out the new version.

Machine notes

Supported (tested) machines include:

* Default Debian, Ubuntu, Fedora, CentOS 7, Mint, OpenSUSE and MacOS Mojave (MacPorts) installations
* Bluewaters
* Comet
* Cori
* Stampede 2
* Mike

* TACC machines: defs.local.ini needs to have sourcebasedir = $WORK and basedir =$SCRATCH/simulations configured for this machine. You need to determine $WORK and$SCRATCH by logging in to the machine.

All repositories participating in this release carry a branch ET_2019_10 marking this release. These release branches will be updated if severe errors are found.

The “Mayer” Release Team on behalf of the Einstein Toolkit Consortium (2019-10-25)

* Steven R. Brandt
* Maria Babiuc-Hamilton
* Peter Diener
* Matthew Elley
* Zachariah Etienne
* Giuseppe Ficarra
* Roland Haas
* Helvi Witek

Oct, 2019

# Texas Symposium: early-bird deadline extended

30th Texas Symposium on Relativistic Astrophysics
Sunday 15th to Friday 20th December 2019, Portsmouth, UK

Early-bird payment deadline extended to Friday 8th November

The Texas meetings have covered topics such as black holes, gravitational waves, neutron stars, cosmic rays, dark matter and the early Universe since the first symposium, held in Dallas in 1963. Following the tradition of previous meetings, the 2019 Symposium will cover a broad range of subjects in relativistic astrophysics.

To register online go to http://texas2019.org/

Once the online registration form is completed please pay via the University of Portsmouth online store: https://onlinestore.port.ac.uk/conferences-and-events/technology/icg/30th-texas-symposium-on-relativistic-astrophysics

We look forward to seeing you in Portsmouth this December!
Marco Bruni and David Wands
on behalf of the Scientific and Local Organising Committees
texas2019[AT]port.ac.uk

# Nominations for the 2020 IUPAP General Relativity and Gravitation Young Scientist Prize are now open

The IUPAP Young Scientist Prizes recognize outstanding achievements of scientists at early stages of their career. Each prize consists of a certificate citing the contributions made by the recipient, a medal and 1000 euros.

The conditions for the prize are:

The Prize can be for work in any area of relativity and gravitation, theoretical or experimental.

On 1 February 2020, nominees must have a maximum of eight years of research experience (excluding career interruptions) following the Ph.D. (or equivalent) degree. They are expected to have displayed significant achievement and exceptional promise for future achievements in relativity and gravitation.

The primary nominator MUST BE A MEMBER of the International Society on General Relativity and Gravitation. Writers of support letters and candidates need not be members.

The nomination deadline is 1 Feb 2020.

Additional details may be found at http://www.isgrg.org/IUPAPprize.php.

# SageMath 8.9 is out

SageMath 8.9 has just been released. It has new features regarding symbolic calculus on manifolds. In particular, some tutorials about vector calculus have been added and computations related to the extrinsic geometry of hypersurfaces have been improved. For more details, see
https://sagemanifolds.obspm.fr/changelog.html

SageMath is a Python-based free computer algebra system, with some differential geometry and tensor calculus capabilities implemented via the SageManifolds project (https://sagemanifolds.obspm.fr/). See https://sagemanifolds.obspm.fr/examples.html for examples of use, in particular in the context of general relativity.

# Translation of Lobachevsky’s papers on non-Euclidean geometry

Nikolai I. Lobachevsky, The Foundations of Geometry: Works on Non-Euclidean Geometry (Minkowski Institute Press, Montreal 2019), 210 pages

Description:

Neither general relativity (which revealed that gravity is merely manifestation of the non-Euclidean geometry of spacetime) nor modern cosmology would have been possible without the almost simultaneous and independent discovery of non-Euclidean geometry in the 19th century by three great mathematicians – Nikolai Ivanovich Lobachevsky, Janos Bolyai and Carl Friedrich Gauss (whose ideas were later further developed by Georg Friedrich Bernhard Riemann).

This volume contains three works by Lobachevsky on the foundations of geometry and non-Euclidean geometry: “Geometry”, “Geometrical investigations on the theory of parallel lines” and “Pangeometry”. It will be of interest not only to experts and students in mathematics, physics, history and philosophy of science, but also to anyone who is not intimidated by the magnitude of one of the greatest discoveries of our civilization and would attempt to follow (and learn from) Lobachevsky’s line of thought, helpfully illustrated by over 130 figures, that led him to the discovery.

# Living Reviews in Relativity: “The causal set approach to quantum gravity”

The open-access journal Living Reviews in Relativity has published a new review article on 27 September 2019:

Sumati Surya,
“The causal set approach to quantum gravity”,
Living Rev Relativ (2019) 22:5
https://doi.org/10.1007/s41114-019-0023-1

Abstract:
The causal set theory (CST) approach to quantum gravity postulates that at the most fundamental level, spacetime is discrete, with the spacetime continuum replaced by locally finite posets or “causal sets”. The partial order on a causal set represents a proto-causality relation while local finiteness encodes an intrinsic discreteness. In the continuum approximation the former corresponds to the spacetime causality relation and the latter to a fundamental spacetime atomicity, so that finite volume regions in the continuum contain only a finite number of causal set elements. CST is deeply rooted in the Lorentzian character of spacetime, where a primary role is played by the causal structure poset. Importantly, the assumption of a fundamental discreteness in CST does not violate local Lorentz invariance in the continuum approximation. On the other hand, the combination of discreteness and Lorentz invariance gives rise to a characteristic non-locality which distinguishes CST from most other approaches to quantum gravity. In this review we give a broad, semi-pedagogical introduction to CST, highlighting key results as well as some of the key open questions. This review is intended both for the beginner student in quantum gravity as well as more seasoned researchers in the field.

Please, visit frequently our relativity channel (https://www.springer.com/gp/livingreviews/relativity) at http://livingreviews.org for other news.

# GRG Editor’s Choice: recent highlight articles

In each volume of the journal General Relativity and Gravitation (GRG), a few papers are marked as “Editor’s Choice”. The primary criteria is original, high-quality research that is of wide interest within the community. These recent articles deserves special attention:

Shamik Banerjee,
“Symmetries of free massless particles and soft theorems”,
Gen Relativ Gravit (2019) 51: 128.
https://doi.org/10.1007/s10714-019-2609-z

Pierre Martin-Dussaud,
“A primer of group theory for Loop Quantum Gravity and spin-foams”,
Gen Relativ Gravit (2019) 51: 110.
https://doi.org/10.1007/s10714-019-2583-5

Guillaume Bossard and Severin Luest,
“Microstate geometries at a generic point in moduli space”,
Gen Relativ Gravit (2019) 51: 112.
https://doi.org/10.1007/s10714-019-2584-4

Joan Garcia i Tormo and Marika Taylor,
“One point functions for black hole microstates”,
Gen Relativ Gravit (2019) 51: 89.
https://doi.org/10.1007/s10714-019-2566-6

Please, browse all Editor’s Choice articles at:
https://www.springer.com/gp/livingreviews/relativity/grg-editors-choice

Frank Schulz
Publishing Editor GRG

# Hans-Peter Kuenzle

It is with great sadness that we inform you of the death of our mentor, colleague, and friend Hans-Peter Kuenzle. Hans passed away on September 12, 2019, in Edmonton, Canada.

Hans was born in Kreuzlingen, Switzerland, in 1940. After undergraduate studies at ETH (Zuerich), where one of his mentors was Heinz Hopf, he moved on to King’s College London where he received his PhD in 1967 under the supervision of Prof Hermann Bondi. Hans held a postdoctoral appointment at UC Berkeley before joining the University of Alberta in 1970. He was promoted to Full Professor in 1980 and retired from the University of Alberta in 2006.

Hans made important contributions in mathematical relativity. He was well-known for his work on the geometric formulation of the Newtonian limit, the uniqueness problem for the static fluid ball, and the Einstein-Yang-Mills equations. His co-discovery of the SU(2) coloured black hole solutions of the static Einstein-Yang-Mills equations was among his best-known and most influential results.

Hans is survived by his wife Nicole and their four children.

Todd Oliynyk and Eric Woolgar

# GRG Topical Collection “The Fuzzball Paradigm”

Call for papers contributing to special article collection

We solicit manuscripts on “The Fuzzball Paradigm” for inclusion in a Topical Collection of the journal General Relativity and Gravitation.

The fuzzball proposal is a paradigm for black holes. In the conventional picture of a black hole, the region around the horizon is in the vacuum state. In the fuzzball paradigm, string theory effects modify the interior of the black hole up to the horizon scale. The proposal posits that the radiation leaving from a non-extremal fuzzball carries information just like radiation from a piece of burning coal. In recent years, these ideas have been widely explored by a number of authors. This Topical Collection plans to explore the ideas and advances in this area.

Topics to be included in this collection include, but are not limited to:

– Fuzzball solutions and their properties
– D1-D5 CFT
– Smooth solutions of alternative theories of gravity
– Black Hole information
– AdS/CFT and the fuzzball proposal
– Classical and quantum properties of black hole microstates

Articles with possibly indirect implications for the fuzzball proposal are also welcome.

Authors are invited to submit through the website https://www.editorialmanager.com/gerg/. Please indicate that your manuscript is intended for inclusion in the special issue “T.C. : The Fuzzball Paradigm”. For preparation, please follow the instructions for authors available at https://www.springer.com/journal/10714

Papers will be published continuously and will appear (as soon as accepted) on the journal website. All submitted papers will be refereed according to the usual high standards of the journal.

We look forward to receiving your submission!

Samir D. Mathur (Guest Editor), David Turton (Guest Editor), or Amitabh Virmani (GRG Associate Editor).

# COST GWverse: Exchange of researchers working on gravitational-wave and black hole physics

In the context of the European COST Action CA16104 on Gravitational waves, black holes and fundamental physics (GWverse), grants for short term scientific missions (STSMs) are available. We are inviting you to submit proposals for STMSs starting after Nov 1, 2019 and ending before Apr 30, 2020 (applications outside this timeframe will be discarded).

This call starts on Sep 1 and closes Oct 15, 2019. All proposals will be reviewed and the results will be announced by Oct 31, 2019.

The selection committee will take into account the geographical distribution of host and home institution, matching of funds by the host, the scientific proposal and the experience of the applicant (preference is given to Early Career Investigators).

Successful applicants will be expected to join as members of one (or more) of the Action’s Working Groups. STSM recipients should acknowledge the COST Action in any publication or talks, through the use of the COST logo and the statement “The authors would like to acknowledge networking support by the COST Action GWverse CA16104”.

STSMs are a great opportunity for all scientists within the COST Action to exchange visits, nurture collaborations, or develop new ones. Further details are available at the GWverse webpage: https://gwverse.tecnico.ulisboa.pt/stsms/

# Stephen Siklos

I have heard from his daughter Tabitha that Stephen Siklos died on 17 August 2019. He had been a postdoc with me and a co-author of papers and was a personal friend. He was for some years the Director of Studies in Mathematics at Newnham College, Cambridge, and later Senior Tutor at Jesus College, and played a key role in the University’s Mathematics Department, coordinating its teaching quality assurance policies.

Tabitha wrote “I am sorry to have to tell you the sad news that my father Stephen died peacefully in the early hours of this morning, while he was at home with his family. He had been ill for a few months and he bore his diagnosis and illness with stoicism and with his usual wry humour intact until the very end.”

# Living Reviews in Relativity: “Testing the nature of dark compact objects: a status report”

The open-access journal Living Reviews in Relativity has published a new review article on 8 July 2019:

Vitor Cardoso and Paolo Pani,
“Testing the nature of dark compact objects: a status report”,
Living Rev Relativ (2019) 22:4
https://doi.org/10.1007/s41114-019-0020-4

Abstract:
Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objects tells us that massive, dark and compact objects are black holes. Any observation suggesting otherwise would be an indication of beyond-the-standard-model physics. Null results strengthen and quantify the Kerr black hole paradigm. The advent of gravitational-wave astronomy and precise measurements with very long baseline interferometry allow one to finally probe into such foundational issues. We overview the physics of exotic dark compact objects and their observational status, including the observational evidence for black holes with current and future experiments.

Please, visit frequently our relativity channel (https://www.springer.com/gp/livingreviews/relativity) at http://livingreviews.org for other news.

# Special Issue “Quantum Group Symmetry and Quantum Geometry”

Dear Colleagues,

Quantum groups appeared during the eighties as the underlying algebraic symmetries of several two-dimensional integrable models. They are noncommutative generalizations of Lie groups endowed with a Hopf algebra structure, and the possibility of defining noncommutative spaces that are covariant under quantum group (co)actions soon provided a fruitful link with noncommutative geometry. At the same time, when quantum group analogues of the Lie groups of spacetime symmetries (Galilei, Poincare’ and (anti-) de Sitter) were constructed, they attracted the attention of quantum gravity researchers. In fact, they provided a possible mathematical framework to model the “quantum” geometry of space-time and the quantum deformations of its kinematical symmetries at the Planck scale, where nontrivial features are expected to arise because of the interplay between gravity and quantum theory.

This Special Issue is open to contributions dealing with any of the many facets of quantum group symmetry and their generalizations. On the more formal side, possible topics include the theory of Poisson-Lie groups and Poisson homogeneous spaces as the associated semiclassical objects; Hopf algebras; the classification of quantum groups and spaces, their representation theory and its connections with q-special functions; the construction of noncommutative differential calculi; and the theory of quantum bundles. On application side, possible topics are: classical and quantum integrable models with quantum group invariance; the applications of quantum groups in different (2+1) quantum gravity contexts (like combinatorial quantisation, state sum models or spin foams); and quantum kinematical groups and their noncommutative spacetimes in connection with deformed special relativity and quantum gravity phenomenology.

Prof. Angel Ballesteros
Dr. Giulia Gubitosi
Prof. Francisco J. Herranz
Guest Editors

# GRG Editor’s Choice free-to-read for GR22/Amaldi13

On the occasion of the GR22/Amaldi13 conference, all recent GRG Editor’s Choice articles will be free-to-read during July 2019!

In each volume of the journal General Relativity and Gravitation (GRG), a few papers are marked as “Editor’s Choice”. The primary criteria is original, high-quality research that is of wide interest within the community. This recent article deserves special attention:

Alan A. Coley,
“Mathematical general relativity”,
Gen Relativ Gravit (2019) 51: 78.
https://doi.org/10.1007/s10714-019-2559-5

Please, browse all Editor’s Choice articles at:
https://www.springer.com/gp/livingreviews/relativity/grg-editors-choice

Frank Schulz
Publishing Editor GRG

# Death of Don Witt

It is with great sadness that I write to let you know that Don Witt passed away April 19th after a long battle with cancer. Don received his Ph.D. from the University of Wisconsin, Milwaukee under John Friedman. After positions at University of California, Santa Barbara and Syracuse University, he eventually became faculty at the University of British Columbia. He was best known for his discovery that homotopy was not equivalent to isotopy for homeomorphisms of 3-manifolds and for his work on topological censorship. He will be sorely missed by his family and colleagues.

Kristin Schleich

# News of the International School of Astrophysics Daniel Chalonge Hector de Vega, Paris, France

Open Session on The New Universe, Dark Energy and the New Black Holes, on Thursday, June 27, 2019 at the College of Spain at Paris, International University City of Paris, 7 boulevard Jourdan, 75014 Paris

Addressed to specialists, non-specialists, teachers, students, post-docs, mediators, journalists. It brings together researchers from different disciplines and diverse personalities.

On the Program: The Standard Model of the Universe beyond the Planck scale: The New Universe and the Quantum light-cone. The New Quantum Phase of the Universe. The New Black Holes.

Dark energy = Vacuum energy = Cosmological constant = Temperature and Entropy of the Universe.

-The scientific programs of the Italian Space Agency.

-The image of the black hole explained by Norma Sanchez. The challenge today is to “see” the interior … Chandrasekhar’s triumph over Eddington …

Victor Hugo and the Observatoire de Paris …

“And that’s not all ….” (Quote from Henri Poincare’)

Announcement and program: https://www.obspm.fr/ecole-internationale-d-4072.html

Brochure and invitation: https://chalonge-devega.fr/Invitation27Juin2019.pdf

To know more: https://chalonge-devega.fr/Programme2019.html

With compliments and kind regards,
International School Daniel Chalonge Hector de Vega
https://chalonge-devega.fr/

# International Master in Mathematical Physics at Leipzig University, Germany

Following the footprints of famous former professors such as W. Heisenberg, F. Klein or F. Bloch in our new 2-year master course students learn general principles of mathematics and theoretical physics, in-depth knowledge on selected topics and do independent research under the guidance of a professor. By solving complex problems and transferring concepts to related fields, the students prepare for a job in academia or industry and economy.

Special features:
– international – English as course language
– interdisciplinary – joint initiative of Mathematics and Physics departments
– forefront research – supported by the local Max Planck Institute for Mathematics in the Sciences
– no tuition fees; semester fee of 220 EUR

Students can shape the program along their own preferences! We offer a wide range of courses on:
– Dynamical Systems
– Differential Geometry
– Stochastic Processes
– Gravity and Cosmology
– Condensed and Soft Matter
– Partial Differential Equations
– Particles and Quantum Fields

We would be more than happy to welcome interested students in our vibrant city with a rich cultural scene, affordable housing and a lot of green spaces and nearby lakes. The course starts annually in October. Application deadlines (May 31st – September 15th) depend on the current degree of the applicant. For more details, please refer to our program website: www.uni-leipzig.de/mathematical-physics

# Living Reviews in Relativity: “Lorentzian causality theory”

The open-access journal Living Reviews in Relativity has published a new review article on 3 June 2019:

Ettore Minguzzi,
“Lorentzian causality theory”
Living Rev Relativ (2019) 22:3.
https://doi.org/10.1007/s41114-019-0019-x

Abstract:
I review Lorentzian causality theory paying particular attention to the optimality and generality of the presented results. I include complete proofs of some foundational results that are otherwise difficult to find in the literature (e.g. equivalence of some Lorentzian length definitions, upper semi-continuity of the length functional, corner regularization, etc.). The paper is almost self-contained thanks to a systematic logical exposition of the many different topics that compose the theory. It contains new results on classical concepts such as maximizing curves, achronal sets, edges, horismos, domains of dependence, Lorentzian distance. The treatment of causally pathological spacetimes requires the development of some new versatile causality notions, among which I found particularly convenient to introduce: biviability, chronal equivalence, araying sets, and causal versions of horismos and trapped sets. Their usefulness becomes apparent in the treatment of the classical singularity theorems, which is here considerably expanded in the exploration of some variations and alternatives.

Please, visit frequently our relativity channel (https://www.springer.com/gp/livingreviews/relativity) at http://livingreviews.org for other news.

# Master in Mathematical Physics, Tuebingen, Germany

We are accepting applications for the international master program in Mathematical Physics for October 2019. It is a 2 year master program jointly run by the mathematics and the physics departments, the application deadline is 15th of July 2019.

The program is centered around the core modules Geometry in Physics, Mathematical Relativity, Mathematical Quantum Mechanics, and Mathematical Statistical Physics. More information as well as a poster and a flyer can be found on the program website http://www.math.uni-tuebingen.de/mmp.

We would be very thankful if you could forward this information to your colleagues and to any undergraduate students who might be interested in applying.

# Living Reviews in Relativity: “Advanced quantum techniques for future gravitational-wave detectors”

The open-access journal Living Reviews in Relativity has published a new review article on 29 April 2019:

Stefan L. Danilishin, Farid Ya. Khalili, Haixing Miao,
“Advanced quantum techniques for future gravitational-wave detectors”,
Living Rev Relativ (2019) 22: 2.
https://doi.org/10.1007/s41114-019-0018-y

Abstract:
Quantum fluctuation of light limits the sensitivity of advanced laser interferometric gravitational-wave detectors. It is one of the principal obstacles on the way towards the next-generation gravitational-wave observatories. The envisioned significant improvement of the detector sensitivity requires using quantum non-demolition measurement and back-action evasion techniques, which allow us to circumvent the sensitivity limit imposed by the Heisenberg uncertainty principle. In our previous review article (Danilishin and Khalili in Living Rev Relativ 15:5, 2012), we laid down the basic principles of quantum measurement theory and provided the framework for analysing the quantum noise of interferometers. The scope of this paper is to review novel techniques for quantum noise suppression proposed in the recent years and put them in the same framework. Our delineation of interferometry schemes and topologies is intended as an aid in the process of selecting the design for the next-generation gravitational-wave observatories.

Please, visit frequently our relativity channel (https://www.springer.com/gp/livingreviews/relativity) at http://livingreviews.org for other news.

# GRG Editor’s Choice: recent highlight articles

In each volume of the journal General Relativity and Gravitation (GRG), a few papers are marked as “Editor’s Choice”. The primary criteria is original, high-quality research that is of wide interest within the community. These recent articles deserves special attention:

Kastytis Zubovas, Andrew R. King,
“The M–$\sigma$ relation between supermassive black holes and their host galaxies”,
Gen Relativ Gravit (2019) 51: 65.
https://doi.org/10.1007/s10714-019-2549-7

Sudipta Sarkar,
“Black hole thermodynamics: general relativity and beyond”,
Gen Relativ Gravit (2019) 51: 63.
https://doi.org/10.1007/s10714-019-2545-y

Brian Allen,
“Sobolev stability of the Positive Mass Theorem and Riemannian Penrose Inequality using inverse mean curvature flow”,
Gen Relativ Gravit (2019) 51: 59.
https://doi.org/10.1007/s10714-019-2542-1

Please, browse all Editor’s Choice articles at:
https://www.springer.com/gp/livingreviews/relativity/grg-editors-choice

Frank Schulz
Publishing Editor GRG

# Gravity Research Foundation, Awards for Essays for 2019

Gravity Research Foundation, Awards for Essays for 2019

The trustees are pleased to announce the Awards for Essays for 2019.

1. $4,000 – Information Content of the Gravitational Field of a Quantum Superposition by Alessio Belenchia[1], Robert M. Wald[2], Flaminia Giacomini[3], Esteban Castro-Ruiz[3], Caslav Brukner[3], and Markus Aspelmeyer[3], [1]Centre for Theoretical Atomic, Molecular, and Optical Physics, School of Mathematics and Physics, Queen’s University, Belfast BT7 1NN, United Kingdom, [2]Enrico Fermi Institute and Department of Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, Il 60637, [3]Institute for Quantum Optics and Quantum Information (IQOQI), Boltzmanngasse 3, 1090 Vienna, Austria; e-mail: a.belenchia@qub.ac.uk, rmwa@uchicago.edu, flaminia.giacomini@univie.ac.at, esteban.castro.ruiz@univie.ac.at, caslav.brukner@univie.ac.at, markus.aspelmeyer@univie.ac.at 2.$1,250 – Non-Perturbative de Sitter Vacua via alpha’ Corrections by Olaf Hohm[1] and Barton Zwiebach[2], [1]Institute for Physics, Humboldt University Berlin, Zum Grossen Windkanal 6, D-12489 Berlin, Germany, [2]Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139; e-mail: ohohm@physik.hu-berlin.de, zwiebach@mit.edu

3. $1,000 – Can Fermionic Dark Matter Mimic Supermassive Black Holes? by C. R. Arguelles[1], A. Krut[2], J. A. Rueda[2][3], and R. Ruffini[2][4], [1]Instituto de Astrofisica de La Plata, (CCT La Plata, CONICET, UNLP), Paseo del Bosque, B1900FWA La Plata, Argentina, [2]ICRANet, Piazza della Repubblica 10, I-65122 Pescara, Italy, [3]INAF, Istituto de Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, 00133 Rome, Italy, [4]INAF, Viale del Parco Mellini 84, 00136 Rome, Italy; e-mail: charly@carina.fcaglp.unlp.edu.ar, andreas.krut@icranet.org, jorge.rueda@icra.it, ruffini@icra.it 4.$750 – How to Hide a Cosmological Constant by Steven Carlip, Department of Physics, University of California, Davis, CA 95616; e-mail: carlip@physics.ucdavis.edu

5. \$500 – Einstein’s Dream by Richard T. Hammond, Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 and Army Research Office, Research Triangle Park, 800 Park Offices Dr, Durham, NC 27703; e-mail: rhammond@email.unc.edu

Selected for Honorable Mention this year were (listed in alphabetical order): Fotios K. Anagnostopoulos, Georgios Kofinas, and Vasilios Zarikas; Gustavo Arciniega, Pablo Bueno, Pablo A. Cano, Jose D. Edelstein, Robie A. Hennigar, and Luisa G. Jaime; Sebastian Bahamonde and Mir Faizal; Yang Bai and Nicholas Orlofsky; Spyros Basilakos, Nick E. Mavromatos, and Joan Sola’ Peracaula; Per Berglund, Tristan Huebsch, and Djordje Minic; Alexander Burinskii; ChunJun Cao, Aidan Chatwin-Davies, and Ashmeet Singh; Man Ho Chan; Geoffrey Compere; Yogesh Dandekar; Shounak De, Tejinder P. Singh, and Abhinav Varma; Tevian Dray and Carlo Rovelli; Arthur E. Fischer; Yuan K. Ha; Dennis Hansen, Jelle Hartong, and Niels A. Obers; Shahar Hod; Ted Jacobson and Manus Visser; Jose Beltran Jimenez, Lavinia Heisenberg, and Tomi S. Koivisto; Nemanja Kaloper; Philip D. Mannheim; Samir D. Mathur; F. Melia; K. Narayan; T. Padmanabhan; Giandomenico Palumbo; Paolo Pani and Andrea Maselli; Tsvi Piran and Bernard F. Schutz; Marco Piva; Suvrat Raju; S. Shankaranarayanan; Martina Toscani, Giuseppe Lodato, and Elena Maria Rossi; Asher Yahalom; Ding-fang Zeng.

This announcement and abstracts of award-winning and honorable mention essays will be posted when ready on our web site, http://www.gravityresearchfoundation.org. The five award-winning essays will be published in a special issue of the International Journal of Modern Physics D (IJMPD). They will also be posted at a later date on our web site.

# Death of Chris Clarke

I am sure that colleagues will be saddened to hear of the death of Chris Clarke who passed away on 16th April. Chris gained his PhD in General Relativity from the University of Cambridge as part of the group led by Dennis Sciama. After positions at Hamburg and York, Chris moved to Southampton in 1986 to take up the Chair in Applied Mathematics and lead the GR group.

He was best known for his work on singularities summarised in his book “The analysis of space-time singularities”. However his work was wide ranging and also covered topics in astrophysics, numerical relativity, the philosophy of quantum theory and the physics of the brain. He left the University of Southampton in 1999 to work free-lance and devote more time to support for environmental and spiritual causes but continued to publish scientific papers on relativity and quantum theory.

# GRG Golden Oldie: The theoretical significance of experimental relativity by R.H. Dicke (1964)

The Golden Oldies series of the journal General Relativity and Gravitation reprints important papers in general relativity theory that were published 30 or more years ago and are either hard to get hold of, or were originally printed in a language other than English.

The latest work has been republished on 30 April 2019:

Dicke, R.H., Republication of: The theoretical significance of experimental relativity, Gen Relativ Gravit (2018) 51: 57. https://doi.org/10.1007/s10714-019-2509-2​​​​​​​

An editorial note by P.J.E. Peebles and a a brief biography by M.A.H. MacCallum are freely available at https://doi.org/10.1007/s10714-019-2508-3

# Important notice to members of the International Society on General Relativity and Gravitation

Members in good standing of the International Society on General Relativity and Gravitation should have received (between 10 April 2019 and 12 April 2019) an email from simplyvoting.com with directions on how to vote in the ongoing ISGRG elections and an email from me alerting you to the election email and also including the Agenda of the ISGRG General Assembly to be held in Valencia on 11 July 2019.

If you did not receive these emails, it may indicate one or more of the following:
(2) Your email service rejected these emails or classified them as “junk”;
(3) You are not considered to be a member in good standing because your dues payments are not current in my records.

Beverly K. Berger
Secretary, International Society on General Relativity and Gravitation

# International Master in Mathematical Physics, Dijon, France

The Department of Mathematics of the Universite de Bourgogne offers a one- or two-year master program in Mathematical Physics.

Advanced students may be admitted to the 2nd year of the Master.

Students who will successfully complete the M.Sc. program will be encouraged to apply to one of the Ph.D. fellowships that will be available for pursuing their studied in Dijon at the doctorate level.

The student will be integrated from the very beginning into the mathematical physics group of the IMB (Institut de Mathematiques de Bourgogne) and will have to prepare by the end of their 2nd year a master dissertation under the supervision of a member of the Institute.

All the lectures will be given in English.

We will also provide several mini courses by the research visitors of the IMB as well as by invited professors in the framework of the Erasmus program.

*The tuition fees are of about 250 euros/year.*

We expect to have up to 10 fellowships for students.

The interested candidates are strongly advised to already get in touch with us, and send a cv to: