Volume 197
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Volume 197
May 6, 2022
Seminar Report
iTHEMS Biology Seminar by Mr. Daiki Kumakura on April 28, 2022
2022-04-30
On April 28th, I talked about the Asgard archaea and the theory of intracellular symbiosis and discussed the mathematical modeling of the symbiosis hypothesis. First, I gave a brief of the classification of the organism as a five-kingdom system and three-domain system. Next, I talked about Asgard archaea, a group of archaea that has received much attention recently. Finally, I discussed the culture of Asgard archaea and the new theory of intracellular symbiosis that has developed as a result. In my presentation, I prepared the idea of mathematical modeling for the new theory. Audience members gave a variety of opinions on this model. In particular, I discussed points where the evolutionary model should be added, whether deterministic or stochastic dominance contributed, and why symbiosis was possible only in two specific species although a variety of symbiotic relationships were possible. I had a meaningful time exchanging opinions and having discussions with various researchers. Thank you so much.
Reported by Daiki Kumakura
Diversity of Asgardarchaota and Theoretical verification of the endosymbiotic theory
April 28 (Thu) at 10:00 - 11:00, 2022
Upcoming Events
Seminar
Introduction to Topological Insulators: Topological Superconductors and Quantum Computing
May 9 (Mon) at 14:00 - 15:30, 2022
Ching-Kai Chiu (Senior Research Scientist, iTHEMS)
References
- A Yu Kitaev, Unpaired Majorana fermions in quantum wires, Phys.-Usp. 44 131 (2001), doi: 10.1070/1063-7869/44/10S/S29
- D. A. Ivanov, Non-Abelian Statistics of Half-Quantum Vortices in p -Wave Superconductors, Phys. Rev. Lett. 86, 268 (2001), doi: 10.1103/PhysRevLett.86.268
Venue: via Zoom
Event Official Language: English
Seminar
Introduction to Topological Insulators: The Ten-fold Classification of Topological Insulators and Superconductors Part.1
May 24 (Tue) at 14:00 - 15:30, 2022
Ching-Kai Chiu (Senior Research Scientist, iTHEMS)
References
- Andreas P. Schnyder, Shinsei Ryu, Akira Furusaki, and Andreas W. W. Ludwig, Classification of topological insulators and superconductors in three spatial dimensions, Phys. Rev. B 78, 195125 (2008), doi: 10.1103/PhysRevB.78.195125
- Alexei Kitaev, Periodic table for topological insulators and superconductors, AIP Conference Proceedings 1134, 22 (2009), doi: 10.1063/1.3149495
Venue: via Zoom
Event Official Language: English
Seminar
Equilibrium or not? Mathematical differences between acute & chronic virus infections
May 25 (Wed) at 13:30 - 15:00, 2022
Catherine Beauchemin (Deputy Program Director, iTHEMS)
The widely acclaimed 1995/1996 papers by Ho, Perelson and others [1,2] demonstrated the important insights that come from mathematical modelling of virus infection kinetics within a person. But there are key dynamical differences between chronic and acute infections, namely whether the infection reaches or maintains some equilibrium or not. In this talk, I will introduce the equations used to describe a virus infection within a person. I will show some of the tricks used by mathematical modellers to extract important rate estimates from measurements in patients infected with chronic diseases, like HIV or Hepatitis C virus. I will explain why it is difficult to extract meaningful information from measurements in patients with an acute infection, like influenza or possibly COVID-19 [3]. I hope to hear from the audience if they have any thoughts about overcoming the issue to extract better rate information from limited data in patients with acute infections.
(This seminar is a joint seminar between Nonequilibrium working group and Biology study group)
References
- Ho DD, Neumann AU, Perelson AS, Chen W, Leonard JM, Markowitz M., Rapid turnover of plasma virions and CD4 lymphocytes in HIV-1 infection, Nature 373 (6510) 123-6 (1995), doi: 10.1038/373123a0
- Perelson AS, Neumann AU, Markowitz M, Leonard JM, Ho DD, HIV-1 dynamics in vivo: virion clearance rate, infected cell life-span, and viral generation time, Science (1996), doi: 10.1126/science.271.5255.1582
- Palmer J, Dobrovolny HM, and Beauchemin CAA, The in vivo efficacy of neuraminidase inhibitors cannot be determined from the decay rates of influenza viral titers observed in treated patients, Sci. Rep., 7:40210 (2017), doi: doi:10.1038/srep40210
Venue: via Zoom
Event Official Language: English
Seminar
Superconducting-like heat current: Effective cancellation of current-dissipation trade-off by quantum coherence
July 25 (Mon) at 13:30 - 15:00, 2022
Tajima Hiroyasu (Assistant Professor, Graduate School of Informatics and Engineering, The University of Electro-Communications)
Recent developments in statistical mechanics have revealed a tradeoff between heat current and dissipation [1,2]. In various situations, this current-dissipation tradeoff represents a relationship between thermal energy flow and entropy increase, similar to Joule’s law W=RI^2.
On the other hand, the coherence effect on the current-dissipation tradeoff has not been thoroughly analyzed. Here, we systematically analyze how coherence affects the current-dissipation tradeoff [3]. The results can be summarized in the following three rules:
- Quantum coherence between different energy levels strengthens the trade-off. In other words, the ratio between the square of the heat current and the entropy production ratio corresponding to electrical resistance R (hereafter referred to as "thermal resistance") is increased by the superposition of different energy levels.
- Coherence between degeneracies weakens the trade-off. That is, thermal resistance is weakened by coherence between degeneracies.
- With enough coherence between degeneracies, we can cancel the trade-off effectively and make the thermal resistance approximately zero. Then, macroscopic heat flow without entropy increase is realized.
These three results directly reveal the coherence effects on heat engine performance. That is, coherence between different energy levels reduces the performance, while coherence between degeneracies increases it. And when there is a sufficient amount of coherence between degeneracies, the efficiency can asymptotically reach the Carnot efficiency (η=η_{Car}-O(1/N)) while the power is O(N).
References
- N. Shiraishi, K. Saito, H. Tasaki, Universal Trade-Off Relation between Power and Efficiency for Heat Engines, Phys. Rev. Lett. 117, 190601 (2016), doi: 10.1103/PhysRevLett.117.190601
- A. C. Barato, U. Seifert, Thermodynamic Uncertainty Relation for Biomolecular Processes, Phys. Rev. Lett. 114, 158101 (2015), doi: 10.1103/PhysRevLett.114.158101
- H. Tajima, K. Funo, Superconducting-like Heat Current: Effective Cancellation of Current-Dissipation Trade-Off by Quantum Coherence, Phys. Rev. Lett. 127, 190604 (2021), doi: 10.1103/PhysRevLett.127.190604
Venue: via Zoom
Event Official Language: English
Paper of the Week
Week 2, May 2022
2022-05-05
Title: High energy emission component, population, and contribution to the extragalactic gamma-ray background of gamma-ray emitting radio galaxies
Author: Yasushi Fukazawa, Hiroto Matake, Taishu Kayanoki, Yoshiyuki Inoue, Justin Finke
arXiv: http://arxiv.org/abs/2204.14019v1
Title: The $a$-points of the Riemann zeta-function and the functional equation
Author: Athanasios Sourmelidis, Jörn Steuding, Ade Irma Suriajaya
arXiv: http://arxiv.org/abs/2204.13887v1
Title: Speed Limits for Macroscopic Transitions
Author: Ryusuke Hamazaki
Journal Reference: PRX Quantum 3, 020319 (2022)
doi: https://doi.org/10.1103/PRXQuantum.3.020319
arXiv: http://arxiv.org/abs/2110.09716v3
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