- First I learned about 2 TeV bump at LHC providing evidence for MG,79 hadron physics (I had realized that it might show itself at LHC only few weeks earlier!
- Then emerged the finding that the knockdown of genes need not affect gene expression providing support for the vision that dark analogs of basic bio-molecules identifiable in terms of dark proton states are behind the biochemistry serving only as a shadow for the deeper quantum biology.
- Two days ago I learned about the discoveries about Pluto by New Horizons space probe and having explanation in terms of the same model that justifies Expanding Earth hypothesis in TGD framework explaining among other things the mysteries of Cambrian explosion in biology.
- Today I learned from Nature News that a team led by H. Auradou reports in the article "Turning Bacteria Suspensions into Superfluids" published in Phys Rev Letters that bacterium swimming in fluid do not only reduce its viscosity associated with shear stress (viscous force parallel to the surface) but makes it to behave in super-fluid like manner above a critical concentration of bacteria.
As the number of bacteria (E. coli) was increased, the viscosity associated with shear stress (the viscous force parallel to the surface) dropped: this in accordance with theoretical expectations. Adding about 6 billion cells (the fluid volume is not mentioned but it seems that the effect occurs above critical density of bacteria), the apparent viscosity dropped to zero - or more precisely, below the experimental resolution. The super-fluid like behavior was preserved above the critical concentration. What is important that this did not happen for dead bacteria: bacteria play an active role in the reduction of viscosity.
Researchers are not able to identify the mechanism leading to the superfluid-like behavior but some kind of collective effect is believed to be in question. The findings suggest that the flagellae - kind of spinning hairs used by the bacteria to propel themselves - should play an essential part in the phenomenon. As bacteria swim, they fight against current, decreasing the local forces between molecules that determine the fluid's viscosity. Above critical density the local effects would somehow become global.
Cates et al have proposed this kind of phenomenon: see the article "Shearing Active Gels Close to the Isotropic-Nematic Transition". The authors speak in the abstract about zero apparent viscosity.
- The title of the article of Cates et al tells that the phenomenon occurs near isotropic-nematic transition. Nematic is defined as a liquid crystal for which the molecules are thread-like and parallel. I dare guess that in the recent case the approximately parallel flagellae would be modelled as liquid crystal like 2-D phase at the surface of bacterium. In the isotropic phase the orientations of the flagellae would be uncorrelated and long range orientational correlations would emerge in the phase transition to nematic phase.
- Also the notions of contractile and extensile gels are introduced. Contraction and extension of gels are though to occur through molecular motors. The transformation of the fluid to apparent superfluid would require energy to run the molecular motors using metabolic energy and ordinary superfluidity would not be in question.
- The model predicts divergence of viscosity for contractile gels. For extensile gels a zero of apparent viscosity is predicted. There is a hydrodynamical argument for how this would occur but I did not understand it. The active behavior of the bacteria would means that the gel like surface phase (nematic liquid crystal) formed by the flagellae extends to reduce viscosity. If I have understood correctly, this applies only to the behavior of single bacterium and is about the reduction of viscosity in the immediate vicinity of cell.
- In TGD inspired biology gel phase corresponds to a phase, which involves flux tube connections between basic units. Flux tubes contain dark matter with non-standard value heff=n× h. The heff changing phase transitions scaling the lengths of flux tubes proportional to heff are responsible for the contractions and extensions of gel.
The extension of the gel should lead to a reduction of viscosity since one expects that dissipative effects are reduced as heff increases and quantum coherence is established in longer scales. Large heff phases are associated with criticality. Now the criticality would be associated with isotropic-nematic phase transition. The parallelization of flagellae would be due to the quantum coherence assignable with the flagellae.
Note that the mechanism used by bacteria to control the liquid flow would be different since now molecular motors are replaced by heff changing phase transitions playing key role in TGD inspired view about biochemistry. For instance, reacting biomolecules find each other by heff reducing phase transition contracting the flux tubes connecting them.
- This model does not yet explain the reduction of apparent viscosity to zero in the entire fluid occurring above a critical density of bacteria. What could happen could be analogous to the emergence of high Tc superconductivity according to TGD. Below pseudo gap temperature the emergence of magnetic flux tube pairs makes possible super-conductivity in short scales. At critical temperature a phase transition in which flux tubes reconnect to form larger thermodynamically stable networks occurs. One can speak about quantum percolation.
The reduction of viscosity for a single bacterium could be based on the phase transition of liquid molecules to dark molecules flowing along the resulting flux tubes with very small friction (large heff) but only below certain scale smaller than the typical distance between bacteria. This would be the analog for what happens below pseudo gap. Above critical density he magnetic flux tubes associated with bacteria would reconnect and forming a net of connected flux tube paths at scale longer than inter-bacterial distances. This would be the counterpart for the emergence of superconductivity by percolation in long scales.
For a summary of earlier postings see Links to the latest progress in TGD.