# SKM 2023 – wissenschaftliches Programm

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# DY: Fachverband Dynamik und Statistische Physik

## DY 40: Stochastic Thermodynamics

### DY 40.1: Vortrag

### Donnerstag, 30. März 2023, 10:00–10:15, ZEU 250

Optimized Work Protocols for the Higgs RNA-Model — •Peter Werner and Alexander K. Hartmann — Institute of Physics, University of Oldenburg, Germany

When a system is driven from one
state to another in a *finite* amount of time
t∈[0,…,τ] by changing an external control parameter according to
a protocol λ(t), some work W is performed.
Here ⟨ W ⟩ ≥ Δ F holds,
where Δ F is the equilibrium free
energy difference between initial and final states.
The protocol λ^{*}(t) minimizing the average amount of work is of
interest, since it tightens the upper bound to Δ F.
The optimum protocols of simple Brownian-particle systems
exhibit distinct jumps especially at the
beginning and end of the process [1,2] and it was speculated that
these are a generic feature for arbitrary systems.

Here the *many-particle* Higgs RNA model
[3] is considered, where work is performed by stretching the RNA through
changing an external force.
For this model, an exact calculation of the free-energy differences
Δ F and the sampling of the equilibrium initial state can be
performed in polynomial time.
The work processes are realized by means of non-equilibrium
Monte-Carlo simulations [4].
The optimum protocols are obtained numerically with the
parallel-tempering approach.
Also for this complex system, the optimum protocols exhibit
distinct jumps at the beginning and end.

[1] T. Schmiedl and U. Seifert, Phys. Rev. Lett., 98, 108301 (2007)

[2] H. Then and A. Engel, Phys. Rev. E 77, 041105 (2008)

[3] P. G. Higgs, Phys. Rev. Lett., 76, 704 (1996)

[4] P. Werner and A. K. Hartmann, Phys. Rev. E 104, 034407 (2021)