CALLISTO Instrument and the e-Callisto Network


United Nations initiated very successfull events like IHY2007 which were immediately followed by the International Space Weather Initiative (ISWI). All of them lead us to support developing countries to participate in 'Western’ science. In 2006, we started to distribute low cost radio spectrometers CALLISTO all over the world for the following reasons:

  1. Developing countries shall become able to do solar science by observing meter-wave radiation of the sun and trying to understand CMEs and coronal heating.
  2. It gave us the opportunity to get observational data of 24h coverage of the sun. Very often radio spectra collected in developing countries are of much better quality than in Europe because their infrastructure is also less developed and therefore they are less suffering from self-produced radio interference(rfi).

This talk gives an overview about the instrument array which is a project, initiated by UN and NASA. I will show some of the instrument locations/antennas with their advantages and disadvantages. Most important solar radio burst types will be shown and the advantage of redundant observations.

Christian Monstein*

*Christian Monstein, is an expert on design and manufacturing of correlation radio receiver for cosmological observations. He is PI of the international radio spectrometer network e-Callisto rfi-monitoring, digital backends and monitoring-software for BINGO (Baryon acoustic oscillations In Neutral Gas Observations), a co-operation between UK, Brazil, Uruguay, South Africa and Switzerland. Design, manufacturing and test of 3Dprinted, corrugated horn-antenna for 5m dish. He is affiliated to ETH Zurich, Institute for Plasma Physics and Astrophysics.

Date: 24 October, 2018
07 Kartik, 2075


Quantum Gravity on Computer: An Introduction to (1+1) Dimensional Causal Dynamical Triangulations without Preferred Foliation


Causal Dynamical Triangulations (CDT) is an approach to Quantum Gravity based on the sum over histories line of research which gives a quantization of classical Einstein gravity using a discrete approximation to the gravitational path integral, and spacetimes are approximated by Minkowskian equilateral triangles. This approach was developed by Renate Loll, Jan Ambjørn, and Jerzy Jurkiewicz. We have used a more recent version of CDT, called CDT without preferred foliation, to write a numerical simulation of quantum spacetimes in (1+1) dimensions. This talk comprises the full-fledged numerical implementation from how we can initialize triangulated spacetime in the form of a data structure to Monte-Carlo moves and finally, how you can contribute to the further development of our software.

Damodar RajBhandari*

*Damodar Rajbhandari, a resident of Pokhara, is a young physicist, scientific programmer & a physics blogger. He has finished bachelor degree in physics from St. Xavier's College, Kathmandu. His research interests include Quantum Gravity, Astrophysics, Quantum Cosmology, Code Optimization.

Date: 22 September, 2018
06 Asoj, 2075


A Materials-Driven Approach to Condensed Matter Physics


Without materials, there can be no condensed matter physics. Indeed, the synthesis of new materials is often the key starting point for advancing our fundamental understanding of underlying physics as well as pursuing technological development. I will start this talk by giving a broad overview of the quest for new materials – Why do we do it? How do we do it? I will then focus on a specific class of materials discovery, the Weyl semimetal, which is essentially a three-dimensional analog of graphene. As such, a Weyl semimetal is a conductor whose low-energy bulk excitations are Weyl fermions. To illustrate these characteristics, I will discuss our recent study of the Weyl semimetal NbAs, presenting magnetotransport signatures of Weyl fermions in this compound. Finally, I will briefly highlight some of our recent efforts in the area of topological matter, driven by specific materials design criteria.

Nirmal J. Ghimire*, PhD

Nirmal J. Ghimire is a Director's Postdoctoral Fellow in Materials Science Division at Argonne National Laboratory. He obtained a PhD in physics from University of Tennessee in 2013 carrying out most of his graduate research at the nearby Oak Ridge National Laboratory. From 2013 to 2015 he was a postdoctoral research associate at Los Alamos National Laboratory. In 2015, he moved to Argonne as a Director's Fellow in the Materials Science Division. From Fall 2018, Nirmal is joining department of physics and astronomy at George Mason University as an assistant professor. His work primarily involves materials design, crystal growth and characterization with an emphasis on transport property studies and neutron diffraction experiments.

Date: 07 July, 2018
23 Asar, 2075


The Most Distant Galaxies


What is a galaxy and how does it form? I will address these fundamental questions of astronomy by focusing on the earliest stages of assembly, which can be explored by observing distant galaxies. In fact, because of the finite speed of light, distant objects are seen as they were in the past: The Hubble Space Telescope observations I will present are allowing us to reach as far as 13.3 billion light years away, showing us how galaxies looked like when the Universe was just 500 Million years old.

Michele Trenti*, PhD

*Michele Trenti, Associate Professor and ARC Future Fellow in the School of Physics at the University of Melbourne (Australia), is an expert on the formation and evolution of galaxies. He uses the Hubble Space Telescope to hunt for distant galaxies with the goal of understanding how stars like our own Sun and galaxies like the Milky Way formed and evolved from early times until today. Originally from Italy, where he obtained the PhD in 2005, he worked around the world at the Space Telescope Science Institute in Baltimore, Maryland, at the University of Colorado, Boulder (USA), and at the University of Cambridge (UK) before joining the University of Melbourne.

Date: 16 June, 2018
02 Asar, 2075


Cosmic-Ray Extremely Distributed Observatory: New Research Perspectives in Astroparticle Physics


The Cosmic-Ray Extremely Distributed Observatory (CREDO) is an infrastructure for global analysis of extremely extended cosmic-ray phenomena, so-called Cosmic Ray Ensembles (CREs), beyond the capabilities of existing discrete detectors and observatories. To date, cosmic-ray research at very high energies has revolved around the detection of air showers initiated by single primary cosmic ray particle, while the search for extremely extended cosmic ray air showers induced by CREs is a scientific terra incognita. Detection of CREs will have a significant impact on ultra-high energy astrophysics, cosmology and the physics of fundamental particle interactions as they can theoretically be formed within both classical (photon-photon interactions) and exotic (e.g., Super Heavy Dark Matter particle decay and interaction) scenarios. I will present the main objectives and current status of CREDO, and briefly discuss some reasons and ways to contribute to CREDO science as well through this talk.

Niraj Dhital*, PhD

*Niraj Dhital is a postdoctoral researcher at Institute of Nuclear Physics, Polish Academy of Sciences, Poland. He did his PhD in Particle Astrophysics from Michigan Technological University, USA, and his M.Sc. in Physics from Tribhuvan University, Nepal. His research interest include, but not limited to, Ultra high energy cosmic rays, and physics beyond the Standard Model. His research outputs have been published as hundreds of original research articles in numerous international peer reviewed journals.

Date: 07 June, 2018
24 Jestha, 2075