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Journal of Biotechnology and Phytochemistry
Volume 1 Issue 3
Chemistry World 2017
Page 72
November 13-15, 2017 Athens, Greece
7
th
World Congress on
Chemistry
The transition path time distribution - protein
folding, quantum mechanics, tunneling times
and uncertainty
Eli Pollak
Weizmann Institute of Science, Israel
Recent experimental measurements of the transition path time
distributions of proteins present theory with challenges. They
lead to barrier heights which are much lower than the free
energies of activation of the observed transitions. Secondly,
can one use the transition path time distribution to obtain
insight into some of the intriguing questions of quantum
mechanics, such as how long does it take to tunnel? In this talk,
I introduce the paradigm of a transition path barrier height
for the protein folding problem, and show that it should be
smaller than the activation energy, resolving the low barrier
height puzzle. The transition path distribution for a parabolic
barrier is derived for arbitrary memory friction. In the second
phase of this talk, the quantum mechanical transition path
time probability distribution will be discussed. Standard
approaches to tunneling times are replaced by considering
time correlation functions. The formalism is used to study the
quantum dynamics of thermal position correlation functions.
Highlights are the proof of a vanishing mean tunneling
time at the parabolic barrier crossover temperature and that
increasing the length of the path traversed decreases the
mean transition time. The mean transition path time is used
to define a coarse-grained momentum for passage from one
side of the barrier to the other. The product of the uncertainty
in this momentum with the uncertainty in the location of the
particle is shown under certain conditions to be smaller than
the ħ/2 formal uncertainty limit.
Eli.pollak@weizmann.ac.ilJ Biotech and Phyto 2017