Neutrinos from cosmic ray interactions in the Sun

Joakim Edsjo, Jessica Elevant, Rikard Enberg, Carl Niblaeus
Cosmic rays hitting the solar atmosphere generate neutrinos that interact and oscillate in the Sun and oscillate on the way to Earth. These neutrinos could potentially be detected with neutrino telescopes and will be a background for searches for neutrinos from dark matter annihilation in the Sun. We calculate the flux of neutrinos from these cosmic ray interactions in the Sun and also investigate the interactions near a detector on Earth that give rise to muons. We compare this background with both regular Earth-atmospheric neutrinos and signals from dark matter annihilation in the Sun. Our calculation is performed with an event-based Monte Carlo approach that should be suitable as a simulation tool for experimental collaborations. Our program package is released publicly along with this paper.

The Making of the Standard Theory

John Iliopoulos

1. Introduction
The construction of the Standard Model, which became gradually the Standard Theory of elementary particle physics, is, probably, the most remarkable achievement of modern theoretical physics. In this Chapter we shall deal mostly with the weak interactions. It may sound strange that a revolution in particle physics was initiated by the study of the weakest among them (the effects of the gravitational interactions are not measurable in high energy physics), but we shall see that the weak interactions triggered many such revolutions and we shall have the occasion to meditate on the fundamental significance of “tiny” effects. We shall outline the various steps, from the early days of the Fermi theory to the recent experimental discoveries, which confirmed all the fundamental predictions of the Theory. We shall follow a phenomenological approach, in which the introduction of every new concept is motivated by the search of a consistent theory which agrees with experiment. As we shall explain, this is only part of the story, the other part being the requirement of mathematical consistency… Read more at


Quantum Computing and the Entanglement Frontier

John Preskill, CalTech
The quantum laws governing atoms and other tiny objects seem to defy common sense, and information encoded in quantum systems has weird properties that baffle our feeble human minds. John Preskill will explain why he loves quantum entanglement, the elusive feature making quantum information fundamentally different from information in the macroscopic world. By exploiting quantum entanglement, quantum computers should be able to solve otherwise intractable problems, with far-reaching applications to cryptology, materials, and fundamental physical science. Preskill is less weird than a quantum computer, and easier to understand.

Fast Radio Bursts from Extragalactic Light Sails

Manasvi Lingam, Abraham Loeb
We examine the possibility that Fast Radio Bursts (FRBs) originate from the activity of extragalactic civilizations.
Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs.
The characteristic diameter of the beam emitter is estimated through a combination of energetic and engineering constraints, and both approaches intriguingly yield a similar result which is on the scale of a large rocky planet.
Moreover, the optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These `coincidences’ lend some credence to the possibility that FRBs might be artificial in origin.
Other relevant quantities, such as the characteristic mass of the light sail, and the angular velocity of the beam, are also derived.
By using the FRB occurrence rate, we infer upper bounds on the rate of FRBs from extragalactic civilizations in a typical galaxy.
The possibility of detecting fainter signals is briefly discussed, and the wait time for an exceptionally bright FRB event in the Milky Way is estimated.

The Black Hole information problem: past, present, and future

Donald Marolf
We give a brief overview of the black hole information problem emphasizing fundamental issues and recent proposals for its resolution. The focus is on broad perspective and providing a guide to current literature rather than presenting full details. We concentrate on resolutions restoring naive unitarity…

The laws of life

Perhaps the questions were too speculative for his time, but Charles Darwin never considered whether another evolutionary experiment exists in the universe or what such an experiment might look like. Once life emerged on Earth, it proliferated across the planet, assumed remarkable forms, and wrought the extraordinary changes that have now inextricably linked the biosphere and geosphere. The oxygen that you and I breathe originated as the result of photosynthetic activity so pervasive and so productive that it eventually reached levels sufficient to drive a complex multicellular biosphere…

How Dark Matter Came to Matter

Jaco de Swart, Gianfranco Bertone, Jeroen van Dongen
The history of the dark matter problem can be traced back to at least the 1930s, but it was not until the early 1970s that the issue of ‘missing matter’ was widely recognized as problematic. In the latter period, previously separate issues involving missing mass were brought together in a single anomaly. We argue that reference to a straightforward ‘accumulation of evidence’ alone is inadequate to comprehend this episode. Rather, the rise of cosmological research, the accompanying renewed interest in the theory of relativity and changes in the manpower division of astronomy in the 1960s are key to understanding how dark matter came to matter. At the same time, this story may also enlighten us on the methodological dimensions of past practices of physics and cosmology.