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Transcription of genetic information
Ryabov, Artem ; Chvosta, Petr (advisor) ; Slanina, František (referee)
We investigate a one-dimensional diffusive motion of a system of interacting Brownian particles driven by an external time-dependent force. We assume the hard-core interaction between the particles. We construct the exact general solution of the N -particle problem. Specifically, we assume the spatially restricted two-particles dynamics, and the harmonically oscillating driving force. The inter-particle interaction induces effective entropic forces and hence also new effects comparing to the corresponding model without the inter-particle interaction. Especially, we have found an increase (decrease) of the work done on the right (left) particle. Similar effects are exhibited by the one-particle mean position, the one-particle entropy production, and heat released to the bath. These characteristics have been discussed depending on the model parameters. Resonance-like maxima have been detected if we plot the work accepted by the individual particles as the function of the driving frequency. Similarly, the entropy production exhibits a maximum as the function of the bath temperature.
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Nonequilibrium Thermodynamics of Small Systems
Holubec, Viktor ; Chvosta, Petr (advisor) ; Slanina, František (referee)
Title: Nonequilibrium Thermodynamics of Small Systems Author: Viktor Holubec Department: Institute of Theoretical Physics Supervisor: Doc. RNDr. Petr Chvosta, CSc., Department of Macromolecular Physics Abstract: We investigate a microscopic engine based on an externally controlled two-level system. One cycle of the engine operation consists of two strokes. Within each stroke, the two energy levels are driven with a time-independent rate. The occupation probabilities of the two levels are controlled by the underlying Pauli rate equation and they represent the (delayed) system response in respect to the external driving. We give the exact solution of the dynamical equation and discuss its thermodynamical consequences. In between, we investigate the engine's efficiency, the power output, and the performance dependence on the control parameters. Secondly, we introduce an augmented stochastic process which reflects, at a given time, both the occupation probabilities for the two levels and the work done on the system during the previous evolution. Our exact calculation of the evolution operator for the augmented process allows for a detailed discussion of the probability density for the work done during the cycle of the engine operation. In the strongly irreversible regime, the density exhibits important...
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