Simulating quantum field theory with a quantum computer

John Preskill
Forthcoming exascale digital computers will further advance our knowledge of quantum chromodynamics, but formidable challenges will remain. In particular, Euclidean Monte Carlo methods are not well suited for studying real-time evolution in hadronic collisions, or the properties of hadronic matter at nonzero temperature and chemical potential. Digital computers may never be able to achieve accurate simulations of such phenomena in QCD and other strongly-coupled field theories; quantum computers will do so eventually, though I’m not sure when. Progress toward quantum simulation of quantum field theory will require the collaborative efforts of quantumists and field theorists, and though the physics payoff may still be far away, it’s worthwhile to get started now. Today’s research can hasten the arrival of a new era in which quantum simulation fuels rapid progress in fundamental physics.
Read more at https://arxiv.org/pdf/1811.10085.pdf

Who discovered positron annihilation?

Positron annihilatioTim Dunker
In the early 1930s, the positron, pair production, and, at last, positron annihilation were discovered. Over the years, several scientists have been credited with the discovery of the annihilation radiation. Commonly, Thibaud and Joliot have received credit for the discovery of positron annihilation. A conversation between Werner Heisenberg and Theodor Heiting prompted me to examine relevant publications, when these were submitted and published, and how experimental results were interpreted in the relevant articles. I argue that it was Theodor Heiting – usually not mentioned at all in relevant publications – who discovered positron annihilation, and that he should receive proper credit.
Read more at https://arxiv.org/pdf/1809.04815.pdf

Introduction to neutrino astronomy

neutrino flux

Energy dependence of the neutrino fluxes produced by the different nuclear processes in the Sun

Andrea Gallo Rosso, Carlo Mascaretti, Andrea Palladino, Francesco Vissani
This writeup is an introduction to neutrino astronomy, addressed to astronomers and written by astroparticle physicists. While the focus is on achievements and goals in neutrino astronomy, rather than on the aspects connected to particle physics, we will introduce the particle physics concepts needed to appreciate those aspects that depend on the peculiarity of the neutrinos. The detailed layout is as follows: In Sect.~1, we introduce the neutrinos, examine their interactions, and present neutrino detectors and telescopes. In Sect.~2, we discuss solar neutrinos, that have been detected and are matter of intense (theoretical and experimental) studies. In Sect.~3, we focus on supernova neutrinos, that inform us on a very dramatic astrophysical event and can tell us a lot on the phenomenon of gravitational collapse. In Sect.~4, we discuss the highest energy neutrinos, a very recent and lively research field. In Sect.~5, we review the phenomenon of neutrino oscillations and assess its relevance for neutrino astronomy. Finally, we offer a brief overall assessment and a summary in Sect.~6. The material is selected – i.e., not all achievements are reviewed – and furthermore it is kept to an introductory level, but efforts are made to highlight current research issues. In order to help the beginner, we prefer to limit the list of references, opting whenever possible for review works and books.

Read more at https://arxiv.org/pdf/1806.06339.pdf

A short walk through the physics of neutron stars

A schematic cross section of a neutron star illustrating the various regions discussed in the text. The different regions shown are not drawn on scale.

Isaac Vidana
In this work we shortly review several aspects of the physics of neutron stars. After the introduction we present a brief historical overview of the idea of neutron stars as well as of the theoretical and observational developments that followed it from the mid 1930s to the present. Then, we review few aspects of their observation discussing, in particular, the different types of telescopes that are used, the many astrophysical manifestations of these objects, and several observables such as masses, radii or gravitational waves. Finally, we briefly summarize some of theoretical issues like their composition, structure equations, equation of state, and neutrino emission and cooling.
read more at https://arxiv.org/pdf/1805.00837.pdf