Seminars 2020/2021

9th December 2020

Seminar Poster

Seminar
Speaker:

Mareki Honma

Venue:

Online via Zoom https://astron.zoom.us/j/88545312932 (Meeting ID: 885 4531 2932)

Also streamed in real time via YouTube  https://www.youtube.com/watch?v=QfTzWtxU8ZI&feature=youtu.be 

Date and Time:          

9th December 2020, 9am (Irish Time)

Seminar Title:             The sharpest view of the Radio Universe

Abstract:
In this talk, I will present the most recent results of high-resolution maser astrometry with Very Long Baseline Interferometry (VLBI). Maser astrometric surveys have been conducted with the Japanese VERA array and the Bar and Spiral Structure Legacy (BeSSeL) project, aimed at exploring the dynamic structure of the Milky Way.  I will present recent results from these surveys, mainly covering topics on the determination of fundamental parameters, rotation curve measurement, tracing spiral structures, comparisons/calibrations of GAIA astrometry, and so on. I will also cover some topics related to individual maser sources (star forming regions and AGB stars) revealed by VLBI astrometry in combination with other arrays such as the Atacama Large Millimeter Array (ALMA). Finally, I will briefly discuss the future prospects of VLBI astrometry for forthcoming global VLBI in the SKA era. 

7th December 2020

Seminar  Speaker: Dr. Jukka Kiukas
Venue: Online via MS Teams
https://teams.microsoft.com/l/meetup-join/19%3ameeting_MmY0M2ZjYWYtMzc2MS00YTYwLTkxMjUtMDY2OTAzMDk2NjU2%40thread.v2/0?context=%7b%22Tid%22%3a%2246fe5ca5-866f-4e42-92e9-ed8786245545%22%2c%22Oid%22%3a%22a1fc07ee-e1f8-4e7c-b82b-0e9f830a651d%22%7d
Date and Time:  7th December 2020, 4pm
Seminar Title: Joint measurements and quantum noise
Abstract:
In quantum theory, some physical quantities are incompatible, i.e. cannot be simultaneously (jointly) measured with arbitrary precision. While this is traditionally formalised using the well-known Heisenberg Uncertainty Principle, a related approach focuses on how incompatible measurements turn into jointly measurable ones due to “imprecision” induced by random noise. This is motivated by current applications to e.g. quantum computing, where a “quantum processor” is typically subjected to noise from its surroundings. Incompatible measurements are crucial for various quantum information processing tasks, and consequently the study of their “robustness” against noise is an active field of research. In this talk I will first introduce the standard formulation of joint measurability in quantum information theory, and then demonstrate how incompatibility is affected by noise in simple models motivated by physics.

30th November 2020

Seminar Poster

 

Seminar Speaker: Dr. John Cuffe
Venue: Online via MS Teams
https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZjNmMTJlOWYtNDM5Mi00NmE4LWE5ZjAtNTU5YmQ3NTAyYmJh%40thread.v2/0?context=%7b%22Tid%22%3a%2246fe5ca5-866f-4e42-92e9-ed8786245545%22%2c%22Oid%22%3a%22a1fc07ee-e1f8-4e7c-b82b-0e9f830a651d%22%7d
Date and Time:  30th November 2020, 4pm
Seminar Title: Understanding Nanoscale Thermal Transport experimentally through Phonon-Photon Interactions
Abstract:
The understanding and manipulation of phonons in nanostructures is a topic of ever-increasing importance, as heat dissipation and thermal management are critical issues for nanoelectronic and nanophotonic devices. In particular, knowledge of the mean free path distribution of heat-carrying phonons is key to understanding phonon-mediated thermal transport. In this talk, I will review the recent advances in thermal characterization and phonon engineering that have drastically increased the understanding of heat transport and demonstrated efficient ways to control heat propagation in nanomaterials. I will summarize recent device-relevant methodologies of phonon engineering in semiconductor nanostructures and 2D materials. Finally, I will review recent advances in thermal characterization techniques, and discuss their main challenges and limitations. One of the primary uncertainties in the experimentally-challenging area of nanoscale thermal transport is accurately fitting your thermal model to experimental data. Can the powerful tool of Machine Learning overtake the ubiquitous ‘least square fitting’ to better predict real-world values for thermal conductivity, heat capacity, and above all, interface thermal conductance? 

9th November 2020

Seminar Poster 

 

Seminar Speaker:

Dr. Calum Ross

Venue:

Online via MS Teams:
https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZTZkMTlmOWItZTVmZi00YTMxLWE1OTEtZDA4MDRjZGYxM2Mw%40thread.v2/0?context=%7b%22Tid%22%3a%2246fe5ca5-866f-4e42-92e9-ed8786245545%22%2c%22Oid%22%3a%22a1fc07ee-e1f8-4e7c-b82b-0e9f830a651d%22%7d

Date and Time:          

9th November 2020, 4pm

Seminar Title:             Mathematical Models of Topological Solitons

Abstract:
Topological solitons are stable particle like objects which occur in some nonlinear classical field theories. They provide mathematical models for phenomena which occur in many physical systems. I have worked on several of these models, in particular Abelian-Higgs vortices and magnetic skyrmions. I will review some general details about solitons before introducing the models that I have worked on. The focus will be on a recent solvable model for magnetic skyrmions, non-trivial twists in the magnetisation field which occur in certain magnetic materials. This solvable model enables the construction of analytic skyrmion configurations. Many of these configurations showcase features that are observed in more general models, both numerically and experimentally.

 

19th October 2020

Seminar Poster  

 

Seminar Speaker:

Kenzie Nimmo

Venue:

Online via Zoom
https://astron.zoom.us/j/88545312932 (Meeting ID: 885 4531 2932)
Also streamed in real time via YouTube https://youtu.be/aHLBuDP43gc

Date and Time:          

19th October 2020, 3pm (Irish Time)

Seminar Title:             Pin-pointing the positions of repeating Fast Radio Bursts with the European VLBI Network 

Abstract:
Fast radio bursts (FRBs) are bright pulses of coherent radio emission with durations of only a few milliseconds, and unknown extragalactic origin. Some FRBs have been observed to repeat, whereas others appear as one-off events. Currently it still remains unclear whether all FRB sources have the ability to repeat, or if there are multiple populations with different physical mechanisms. Recently, the Galactic magnetar SGR 1935+2154 emitted a very bright radio burst (orders of magnitude brighter than typical Galactic radio bursts from pulsars/magnetars) unveiling a bridge between Galactic sources of radio bursts and FRBs. With the European VLBI Network (EVN) we can precisely localise FRBs to milli-arcsecond precision, identifying not only the host galaxy, but the region within the host that the bursts are originating from. This will help in understanding the FRB progenitor(s) and how FRBs link to Galactic sources. In addition to the real-time correlation observing mode (e-EVN), baseband data can be buffered to study fine time and frequency structures of the bursts, as well as their polarisation properties. In this talk I will discuss our approach to localising repeating FRBs using the EVN, present the localisation of a second repeater, FRB 180619.J0158+65, and present recent results on SGR 1935+2154.

 

 

Department of Physics

Roinn na Fisice

Room 213, 2nd floor, Dept. of Physics, University College Cork, Ireland,

Top