arXiv subjects

Akihiko Matsumoto

Publications and source records attributed to Akihiko Matsumoto.

3 recordsLinked to original sources

arXiv2022

Towards carbon neutral scientific societies: A case study with the International Adsorption Society

With increasing concerns over climate change, scientists must imperatively acknowledge their share in CO2 emissions. Considering the large emissions associated with scientific traveling - especially international conferences - initiatives to mitigate such impact are blooming. With the COVID-19 pandemic shattering our notion of private/professional interactions, the moment should be seized to reinvent science conferences and collaborations with a model respectful of the environment. Yet, despite efforts to reduce the footprint of conferences, there is a lack of a robust approach based on reliable numbers (emissions, carbon offsetting/removals, etc.) to accompany this shift of paradigm. Here, considering a representative scientific society, the International Adsorption Society, we report on a case study of the problem: making conferences carbon neutral while respecting the needs of scientists. We first provide a quantitative analysis of the CO2 emissions for the IAS conference in 2022 related to accommodation, catering, flights, etc. Second, we conduct two surveys probing our community view on the carbon footprint of our activities. These surveys mirror each other, and were distributed two years before and in the aftermath of our triennial conference (also corresponding to pre/post COVID times). By combining the different parts, we propose ambitious recommendations to shape the future of conferences.

physics.soc-ph↗

arXiv2015

Manipulating quantum channels in weak topological insulator nanoarchitectures

In $strong$ topological insulators protected surface states are always manifest, while in $weak$ topological insulators (WTI) the corresponding metallic surface states are either manifest or hidden, depending on the orientation of the surface. One can design a nanostep on the surface of WTI such that a protected helical channel appears along it. In a more generic WTI nanostructure, multiple sets of such quasi-1D channels emerge and are coupled to each other. We study the response of the electronic spectrum associated with such quasi-1D surface modes against a magnetic flux piercing the system in the presence of disorder, and find a non-trivial, connected spectral flow as a clear signature indicating the immunity of the surface modes to disorder. We propose that the WTI nanoarchitecture is a promising platform for realizing topologically protected nanocircuits immune to disorder.

cond-mat.mes-hall↗

arXiv2013

Perfectly conducting channel on the dark surface of weak topological insulators

A weak topological insulator (WTI) bears, generally, an even number of Dirac cones on its surface; they are susceptible of doubling, while on the surface of a certain orientation it shows no Dirac cone. On this "dark" surface of a WTI, we predict the existence of a single pair of isolated 1D perfectly conducting channels that forms either a closed loop or a segment of a line. The former is associated typically with a single atomic-layer-thick island formed on the dark surface, while the latter is shown to be the consequence of a pair of crystal (screw) dislocations terminating on the dark surface.

cond-mat.mes-hall↗