435 research outputs found
Viscosity and diffusion in life processes and tuning of fundamental constants
Viewed as one of the grandest questions in modern science, understanding
fundamental physical constants has been discussed in high-energy particle
physics, astronomy and cosmology. Here, I review how condensed matter and
liquid physics gives new insights into fundamental constants and their tuning.
This is based on two observations: first, cellular life and the existence of
observers depend on viscosity and diffusion. Second, the lower bound on
viscosity and upper bound on diffusion are set by fundamental constants, and I
briefly review this result and related recent developments in liquid physics. I
will subsequently show that bounds on viscosity, diffusion and the newly
introduced fundamental velocity gradient in a biochemical machine can all be
varied while keeping the fine-structure constant and the proton-to-electron
mass ratio intact. This implies that it is possible to produce heavy elements
in stars but have a viscous planet where all liquids have very high viscosity
(for example that of tar or higher) and where life may not exist. Knowing the
range of bio-friendly viscosity and diffusion, we will be able to calculate the
range of fundamental constants which favor cellular life and observers and
compare this tuning with that discussed in high-energy physics previously. This
invites an inter-disciplinary research between condensed matter physics and
life sciences, and I formulate several questions that life science can address.
I finish with a conjecture of multiple tuning and an evolutionary mechanism
Microscopic dynamics and Bose-Einstein condensation in liquid helium
We discuss Bose-Einstein condensation in liquid helium which is consistent
with microscopic dynamics in liquids and high mobility of liquid atoms. We
propose that mobile transit atoms accumulate in the finite-energy state where
the transit speed is set by the speed of sound. In momentum space, this
accumulation operates on the sphere with the radius set by interatomic spacing
and corresponds to zero net momentum. We show that this picture is supported by
experiments and discuss its implications, including the macroscopic wave
function and superfluidity
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