Radars are an important part of the array of tools currently in use to probe the ionosphere and through it, the plasma physical processes associated among other things with dynamos triggered by high altitude  winds and by the solar wind interaction with the earth.  The two types of radars that we use are the so-called "incoherent" and "coherent" scatter radars.  I will show that while the two types of radars rely on identical scattering processes, they use very different power levels to examine the medium.  The power level is so high in incoherent scatter radars that they are able to scrutinize low amplitude plasma waves that are in thermodynamic equilibrium with the medium.  By contrast, coherent scatter radars depend on  the presence of large amplitude plasma irregularities for their echoes. The power level requirements can be so low in the latter case that coherent radars are relatively inexpensive to build and operate, which has allowed researchers to build large networks of such radars over time.  In this talk I will illustrate how the use of these powerful radar tools has evolved and how it keeps evolving partly through technological improvements and partly through an improved understanding of the scattering processes achieved through coupled theoretical and data studies.   I will illustrate this progress with several examples from recent studies which will also make manifest the usefulness of using a large complement of tools, including simultaneous data from both types of radars and data from optical cameras, magnetometers and satellite instrumentation, just to name a few.  

Supernova explosions recycle mass and provide the elements that everything around us is composed from. I will outline the life of a star and its sudden death in the supernova event. What little we know about observed supernova progenitors will be discussed. Following the explosion, what produces the phenomena that we see as supernova remnants? I will conclude by mentioning some of the research carried out here at the University of Calgary.

In one of the planet's most extreme environments, South Pole Station Antarctica, scientists have instrumented more than a cubic kilometer of ice to construct the world's largest neutrino detector to date: the IceCube Neutrino Observatory.  Neutrinos, which interact very rarely in nature, represent an ideal messenger with their ability to travel from their point of production to detection almost entirely unimpeded.  Given its enormous size, IceCube is designed to detect the highest energy neutrinos predicted to be produced in the most violent astrophysical processes (including Gamma Ray Bursts, Black Hole collapse and Active Galactic Nuclei)  I will discuss the feat of designing and constructing the IceCube detector at the South Pole and the first results of searches for high energy neutrinos with this new window to the Universe.

The ability to discriminate current modulations produced by various nucleotides while single-stranded DNA is being electrophoretically driven through a biological nanopore offers a simple and inexpensive technique for DNA sequencing. However to realize the potential of nanopore sequencing, the molecular mechanism of DNA movement through the pore and the interactions of the nucleotide with various pore residues have to be well characterized. Here we applied computational approaches through atomistic Molecular Dynamics and Grand-Canonical Monte-Carlo/Brownian Dynamics simulations to investigate DNA translocation and interactions with the biological nanopore, a-Hemolysin (aHL), and compared the results with data obtained from experiments. Equilibrium and non-equilibrium (with an account for electric field acting on a system) MD simulations of all-atom models of homopolymeric DNA (polydA or polydC) translocating through both wild-type and mutant aHL pores provided results that qualitatively match the contrast in ionic current block produced by each base in experimental studies. Atomistic Free Energy Simulations (FES) with the “swarm-of-trajectories” method also provide for the first time insight into the potential energy landscape governing of the DNA conformational dynamics within the pore. The result also agrees with experiments indicating an asymmetric periodic potential.

If you wanted to get to the valley on the other side of a hill, you would have to go over the hill or around it, expending much energy in the process. A quantum particle, on the other hand, has some probability of quantum mechanically tunneling through the hill. In fact, if you wait just the right amount of time, the probability of finding the quantum particle on the other side of the hill becomes exactly one. If the landscape is made just right, then a quantum particle can find its way from a nearby valley to a distant one without ever having large probability of being found in any intermediate location. Under certain circumstances, the transit time is exponentially faster than for any classical particle. If one considers the valleys as possible inputs or outputs of a computation, then tailoring the landscape corresponds to designing a function. I will describe how quantum tunneling can implement quantum algorithms that are more efficient than any known classical ones, and how one might build real systems that accomplish these tasks.

Controlling and measuring the quantum state of physical systems has long motivated researchers searching for insight into the laws of nature, understanding the behaviour of materials, and advancing information processing and sensor technology. In my talk I will discuss recent progress using precisely designed optical components –  nanophotonic devices – to allow the properties of quantum systems to be probed using weak beams of light.  In the ultimate limit, nanophotonic devices enable single photons to manipulate the state of atomic and electronic quantum systems.  Of particular recent interest are quantum systems formed by impurities in crystalline materials, the most exciting example of which is the diamond nitrogen vacancy (NV) centre. In diamond based nanophotonic structures, light can be efficiently coupled to individual NV centre electronic spins, which have proven to be fantastic resources for quantum information processing, as well as magnetic field sensing at the nanoscale.  Diamond's well known mechanical properties are also poised to play an exciting role in new tools for manipulating quantum properties of NVs.

The next revision to the International System of Units will emphasize the relationship between the base units and fundamental constants. The proposed changes represent the single largest revision since the introduction of the electrical units in 1948, capturing our basic understanding of physical phenomena and using that to set the scales of our measurement system. The principal obstacle to overcome is related to the SI value for the Planck constant, h, which is essential for redefining the kilogram, the only base unit defined by an artifact. The redefinition of the kilogram cannot proceed without consistency between two very different metrological approaches to measuring Planck constant: a “physics” approach, using watt balances and the equivalence principle between electrical and mechanical force, and a “chemistry” approach that can be viewed as measuring the mass of a single atom of silicon in terms of the SI kilogram. Although much time and effort has been expended on watt balance and silicon experiments, and the techniques are considered to be well established, there are unresolved discrepancies among the existing published data at levels that are not consistent with the stated measurement uncertainties. For the “chemistry” approach, along with the physical characterization of the silicon-28 single crystal spheres (mass, volume and lattice-constant determinations) required to establish a value for the Avogadro constant, the determination of the atomic weight of spheres has previously been attempted by the European Commission’s Institute for Reference Materials and Measurements and by the Physikalisch-Technische Bundesanstalt; however, there were significant and non-correctable differences. As a result, in 2011 NRC was invited to perform an independent assessment of the atomic weight (isotopic composition) of the enriched 28Si material.

Astrophysicists distinguish between three types of compact stars -
white dwarfs, neutron stars, and black holes. These objects possess
most unusual properties which carry information about the fundamental
building blocks of matter, the properties of the strong interaction in
ultra-dense matter, and even of the structure of space-time
itself. This makes compact stars superb astrophysical laboratories for
a broad range of exciting physical/numerical studies, as shown in this
talk.

Particle Physics attempts to unravel the mysteries of the physical universe and present a coherent description of the dynamics. To this end, physical structures and interaction symmetries play an important role.  While preserved symmetries lead to conservation principles, broken symmetries are also of interest to physicists. They reveal new dynamics and new degrees of freedom etc . In  these studies, precision measurements play very important roles as  finding a signature for symmetry breaking is most often a search for a needle in haystack.  

My talk will present a brief survey of known/broken symmetries  and present details of a precision  experiment of time reversal invariance that we have been carrying out for nearly 20 years at the High Energy Accelerator Research Organization (KEK), Japan. 

Cobalt-based Heusler compounds with composition Co2XZ (X=3d transition metal, Z = group 13-14 element) are attracting significant attention due to their predicted high spin polarization, making them ideal materials for spintronic applications. Of these compounds, Co2FeAl0.5Si0.5 has emerged as a champion material do the Fermi level tuning afforded by the quaternary composition.

In this talk, I will discuss the various trends we have observed for a variety of magnetic properties such as magnetic exchange and anisotropy, as a function of the compound’s composition and ordering. As an example, I will discuss the effect annealing and increased atomic ordering has on 30 nm thick single-crystal epitaxial Co2FeAl0.5Si0.5 thin films. In particular, magneto-optical probes such as surface magneto-optical Kerr effect magnetometry, Brillouin light scattering spectroscopy, and soft x-ray absorption spectroscopy have been used to probe various magnetic properties such as anisotropy, quadratic magneto-optical effects, exchange interactions, and the spin and orbital moments using x-ray magnetic circular dichroism (XMCD). XMCD at the metal edges were carried out in total electron yield and transmission modes, allowing a direct comparison of the magnetism at the surface and in the bulk of the film. We find the surface moments are reduced at the Co2FeAl0.5Si0.5 / MgO interface with respect to the bulk, pointing to potential gains in device performance should this MgO / Co2FeAl0.5Si0.5 be optimized.

Recent efforts towards synthesizing Heusler compound nanostructures will also be discussed.