Feb
11
Teaser:

A quantum processor,  using quantum states of light and matter, holds the promise of performing calculations and simulations that are not practical by a classical processor. Many of the key components for a quantum processor have been demonstrated by various research groups and we can expect these components to be integrated into basic quantum processors in the near future. However, there remain significant technical challenges in scaling the system size and making the system robust and flexible. In GTRI ‘s Quantum Information Systems (QIS)  Group, we use...

Feb
07
Teaser:

Low-luminosity GRBs or X-ray flashes (XRFs), which often accompany supernovae, are typically ascribed to either the supernova shock breakout or weak GRBs powered by the central engine of stellar mass. We propose the tidal disruption of a white dwarf (WD) by an intermediate-mass black hole (IMBH) as another channel for XRFs. Such disruptions last for 100-5000 seconds.  The release of gravitational energy over short time generates a powerful flare. The magnetic field is quickly amplified in the fallback material, and then the BH launches a slow uncollimated jet. The emission from jet photosphere dominates X-...

Feb
06
Teaser:

PLEASE NOTE: This is a WEBINAR

Loose sand particles can jam together to become a solid. Think of the dry sand on the beach: it supports your weight so you can walk on it – you don't need to swim in sand. Jammed sand indeed so much resists deformation that it even expands when you try to make it flow. This was already discovered by Osborne Reynolds in 1885. In fact, you can make sand particles jam by making them flow in a container that cannot expand. This effect is known as shear jamming and was discovered only recently. We have now studied the...

Feb
05
Teaser:

Gravitational waves sap orbital angular momentum and energy from a black hole--neutron star (BH-NS) binary, driving it to inspiral and merge. In the violence of merger, the NS may tidally disrupt and form a hot accretion disk with the collimated magnetic fields necessary to launch jets, providing the central engine for one of the most energetic phenomena in the Universe: a gamma-ray burst (GRB). We assess the feasibility of this scenario with numerical relativity simulations of magnetized BH-NS binary mergers, seeding the NS with magnetic fields and exploring their effects on the remnant disk and the gravitational waves. We find that the gravitational waves are likely to be detectable by...

Feb
04
Teaser:

Icicles are harmless and picturesque winter phenomena, at least in cold climates.  The shape of an icicle emerges from a subtle feedback between ice formation, which is controlled by the release of latent heat, and the flow of water over the evolving shape.  The water flow, in turn, determines how the heat flows.  The air around the icicle is also flowing, and all forms of heat transfer are active in the air.  Ideal icicles are predicted to have a universal "platonic" shape, independent of growing conditions.  In addition, many natural icicles exhibit a...

Feb
02
Teaser:

Manipulating the texture of foods is central to cooking.  One common manipulation is to induce a phase transition, for example, from a solid to a liquid state, which can occur both during cooking and eating.  In understanding the phase behavior of food materials, we will consider the protein, carbohydrate, and fat molecules that are components of foods that we eat.  Interestingly, these same molecules can also impart unique physical properties to plants and animals, which are critical...

Feb
02
Teaser:

 

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Jan
31
Teaser:

Superbursts are the most powerful repeating thermonuclear flashes observed from accreting neutron stars. Runaway thermonuclear burning of carbon ignites deep in the star's envelope. Close to the crust, superbursts are sensitive to the ill-understood nuclear physics processes in dense neutron-rich matter. We present the latest numerical simulations of carbon burning. Comparing the tail of the simulated lightcurve to observations constrains the depth of carbon ignition, whereas the start exhibits the signs of a shock caused by detonation. Recently increasing observational evidence points at interaction between X-ray bursts and the accretion disk. As the most powerful X-ray bursts,...

Jan
31
Teaser:

Atom interferometers that use pulses of light for coherent control of matter-wave interference can be used for wide ranging studies of light-matter interactions and for realizing precision measurements in atomic physics. We describe an echo type interferometer that utilizes a relatively simple setup to manipulate laser-cooled Rb atoms in a single ground state manifold. We review progress toward a precise determination of the atomic fine structure constant and gravitational acceleration.

*Work supported by CFI, OIT, OCE, NSERC and York University

Jan
30
Teaser:

PLEASE NOTE: This is a WEBINAR

Scientists for years have been trying to better understand the mechanisms that are responsible for transport and mixing in fluid flow.  Mixing is important as it is used in everything from food preparation to energy production to biomedical devices, and is seen in both single and multiphase environments.  While mixing applications are wide ranging, a complete and proper understanding of mixing and transport mechanisms is still lacking....

Jan
29
Teaser:

PLEASE NOTE: This is a WEBINAR

Two topics in pattern formation for reaction-diffusion equations will be addressed in this talk.  In the first, I will discuss the existence proof for stationary localized spots in the planar and the three-dimensional Swift--Hohenberg equation using geometric blow-up techniques. The spots have a much larger amplitude than that expected from a formal scaling in the far field. One advantage of the...

Jan
29
Teaser:

Multicellular behavior in bacterial biofilms is intimately tied to the production of an extracellular polysaccharide (EPS) matrix that encases the cells and provides physical integrity to the colony as a whole.  As a colony grows from a few cells into a biofilm, a sudden increase in EPS production generates osmotic stresses that cause the biofilm to expand. Moreover, EPS production is triggered by a nutrient depletion gradient that develops in the biofilm due to diffusive mass transport limitations. These polymer physics based biofilm behaviors...

Jan
28
Teaser:

A great part of physics deals with motion, and the essence of sports is the human body in motion.  The components of the human body that produce motion, namely the skeletal muscles and bones, and the sports equipment itself are bound by the laws of physics.  Aspects of various sports, including baseball, basketball, karate, figure skating, golf, tennis, long jump, and more, will be examined using introductory-level physics.  We will also discuss whether we have reached our limits in human performance in certain sports.  All who appreciate the workings of the human body and the...

Jan
24
Teaser:

Supermassive black holes are amazingly exotic and yet ubiquitous objects, residing in the centers of essentially all stellar bulges in galaxies. Recent years have seen remarkable advances in our understanding of how these black holes form and grow over cosmic time, and how energy released by active galactic nuclei (AGN) connects the growth of black holes to their host galaxies and large-scale structures. I will review some recent work that explores these connections, with a focus on statistical studies of AGN clustering and the links between black hole growth and and star formation. I will highlight some new insights into how and when AGN "feedback" is important for galaxy...

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