Stochastic pumping of non-equilibrium steady-states: how molecules adapt to a fluctuating environment

2018 ◽  
Vol 54 (5) ◽  
pp. 427-444 ◽  
Author(s):  
R. D. Astumian

Fluctuations favour state B = (B,B′) based on kinetic asymmetry combined with moderate dissipation rather than state A = (A,A′) in which the absolute amount of dissipation is greater but where there is no kinetic asymmetry.

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 77
Author(s):  
Angus J. Dunnett ◽  
Alex W. Chin

Simulating the non-perturbative and non-Markovian dynamics of open quantum systems is a very challenging many body problem, due to the need to evolve both the system and its environments on an equal footing. Tensor network and matrix product states (MPS) have emerged as powerful tools for open system models, but the numerical resources required to treat finite-temperature environments grow extremely rapidly and limit their applications. In this study we use time-dependent variational evolution of MPS to explore the striking theory of Tamascelli et al. (Phys. Rev. Lett. 2019, 123, 090402.) that shows how finite-temperature open dynamics can be obtained from zero temperature, i.e., pure wave function, simulations. Using this approach, we produce a benchmark dataset for the dynamics of the Ohmic spin-boson model across a wide range of coupling strengths and temperatures, and also present a detailed analysis of the numerical costs of simulating non-equilibrium steady states, such as those emerging from the non-perturbative coupling of a qubit to baths at different temperatures. Despite ever-growing resource requirements, we find that converged non-perturbative results can be obtained, and we discuss a number of recent ideas and numerical techniques that should allow wide application of MPS to complex open quantum systems.


Author(s):  
Claudia Zech ◽  
Marco Evertz ◽  
Markus Börner ◽  
Yves Kayser ◽  
Philipp Hönicke ◽  
...  

The manganese deposition of an aged anode has been investigated with K-edge and L-edge NEXAFS to determine the manganese species. In addition, the absolute amount of manganese could be revealed with reference-free X-ray fluorescence analysis.


1904 ◽  
Vol 4 (1-2) ◽  
pp. 104-105
Author(s):  
M Beloglazov

11 people of scurvy patients of various ages (from 14 to 52 years old) were investigated by the author from the side of blood changes. The main results of the study are as follows: i) The absolute amount of hemoglobin in all the cases studied is reduced; the gradual increase during recovery does not reach the norm even when the number of red blood cells becomes normal.


1926 ◽  
Vol 4 (2) ◽  
pp. 145-154
Author(s):  
JOSEPH NEEDHAM

1. Investigation of the ammonia content of the developing hen's egg shows that though in absolute amount it steadily increases during incubation, in percentage of the embryonic weight it declines. 2. The intensity of production of ammonia reaches its highest point on the fourth day, i.e. five days before that of urea production, and seven days before that of the production of uric acid. 3. The absolute amounts of nitrogen excreted in the form of ammonia are so small, however, that the curve for protein combusted by 100 gm. of embryo each day is hardly affected, and rises to a peak between the eighth and ninth days. 4. These results are compared with others already in the literature of chemical embryology, which seem to bear on the theory of recapitulation. They afford further support to the conception of an ontogenetic succession of energy-sources.


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