2023 Fiscal Year Research-status Report
Thermodynamic inequalities under coarse-graining
| Project/Area Number |
22K13974
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | entropy production / inequalities / diffusion / nonequilibrium |
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| Outline of Annual Research Achievements |
The first result (arXiv 2306.00417, under review) are inequalities for the power-spectral density of state-dependent observables. Such observables, unlike current observables considered in previous works, give a more coarse-grained representation of the underlying dynamics, since they do not direcly measure transitions. While this result is not directly connected to any of the original case studies, the fact that such observables can yield non-trivial estimates on entropy production is surprising.
The second result (arXiv 2310.17929, under review), pertaining to case study 1, are upper bounds on the entropy production in diffusive dynamics. While in most cases, coarse-graining reduces the apparent entropy production, I found that single-particle observables in interacting systems can also over-estimate the entropy production. This complements earlier results, showing that, depending on the knowledge about the dynamics, inequalities under coarse-graining can take either direction.
The third result (arXiv 2404.12761, under review), relevant to case study 2, is an investigation of enhanced diffusion by employing an effective discretized description. Crucially, enhanced diffusion only occurs in out-of-equilibrium situations; a publication about the corresponding thermodynamic inequalities is currently in preparation (see below).
Finally, two of the results of the previous project year was published this year, as Physical Review Letters 131, 167101 and as Physical Review E 107, L052101.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The results in arXiv 2310.17929 show that, suprisingly, single-particle observables can over-estimate entropy production. This, together with results obtained by other groups, provides a satisfatorily complete picture for case study 1.
As for case study 2, the results in arXiv 2404.12761 connect the observation of enhanced diffusion in continuous and discrete models; a publication about the application of this connection to thermodynamic inequalities is currently in preparation.
For case study 3, I was also already able to familiarize myself with the required techniques for running simulations on a GPU.
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| Strategy for Future Research Activity |
During the current and last year of the project, there are two main tasks: The first is finishing a publication about thermodynamic inequalities for continuous and discrete models of enhanced diffusion; the results have already been obtained, so I am confindent this will be completed soon.
The second task is to develop the simulations required for case study 3. I am currently surveying existing software packages to deciede whether they are sufficient, or it is necessary to write new code. Then, performing the simulations and analyizing the results will be the major challenge in this year.
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| Causes of Carryover |
I was planning to attend a the SigmaPhi conference in Greece in July 2023. However, due to the increase in price of international airplane tickets, the total amount necessary would have made the participation uneconomical, so I decided to cancel the participation. However, for the same reason, much of these funds will be needed to attend a workshop in the USA in June 2024. The remaining funds will be used to purchase computer hardware for the simulations for case study 3.
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