Nonequilibrium Thermodynamics of Biochemical Clocks: From Single to Synchronized Oscillators
Dr. Yuansheng Cao
Department of Physics
UC San Diego
ABSTRACT
Biochemical oscillation is one of the most important way in living systems to track the information of time, or to communicate with population members. A good clock needs to be function accurately in the presence of noise and at the same time respond sensitively to external signals. Low fluctuation and high sensitivity are incompatible in equilibrium systems due to the fluctuation-dissipation theorem (FDT). In biology, biochemical oscillators are fueled by dissipative processes such as ATP hydrolysis, which is inherently nonequilibrium and the FDT is broken. In our recent work, we show that for a single oscillator, the lower bound of oscillation phase fluctuation, and the upper bound of phase sensitivity are determined by the free energy dissipation. Real biological clocks are composed of multiple oscillators and synchronization is necessary to drive their collective dynamics. Inspired by the cyanobacterial circadian clock, we proposed a model of coupled oscillators. We find that synchronization of oscillators cost free energy even though the coupling is conservative. By analytical solving the model, we show that the many-body system goes through a nonequilibrium phase transition driven by energy dissipation.
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