Browsing by Author "Kutvonen, A."
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- Entropy production in a non-Markovian environment
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2015-07-06) Kutvonen, A.; Ala-Nissila, T.; Pekola, J.Stochastic thermodynamics and the associated fluctuation relations provide the means to extend the fundamental laws of thermodynamics to small scales and systems out of equilibrium. The fluctuating thermodynamic variables are usually treated in the context of either isolated Hamiltonian evolution, or Markovian dynamics in open systems. However, there is no reason a priori why the Markovian approximation should be valid in driven systems under nonequilibrium conditions. In this work, we introduce an explicitly non-Markovian model of dynamics of an open system, where the correlations between the system and the environment drive a subset of the environment out of equilibrium. Such an environment gives rise to a new type of non-Markovian entropy production term. Such non-Markovian components must be taken into account in order to recover the fluctuation relations for entropy. As a concrete example, we explicitly derive such modified fluctuation relations for the case of an overheated single electron box. - Influence of nanoparticle size, loading, and shape on the mechanical properties of polymer nanocomposites
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2012) Kutvonen, A.; Rossi, G.; Puisto, S. R.; Rostedt, N. K.; Ala-Nissilä, TapioWe study the influence of spherical, triangular, and rod-like nanoparticles on the mechanical properties of a polymernanocomposite (PNC), via coarse-grained molecular dynamics simulations. We focus on how the nanoparticle size, loading, mass, and shape influence the PNC’s elastic modulus, stress at failure and resistance against cavity formation and growth, under external stress. We find that in the regime of strong polymer-nanoparticle interactions, the formation of a polymer network via temporary polymer-nanoparticle crosslinks has a predominant role on the PNC reinforcement. Spherical nanoparticles, whose size is comparable to that of the polymermonomers, are more effective at toughening the PNC than larger spherical particles. When comparing particles of spherical, triangular, and rod-like geometries, the rod-like nanoparticles emerge as the best PNC toughening agents. - On-Chip Maxwell's Demon as an Information-Powered Refrigerator
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2015-12-30) Koski, Jonne; Kutvonen, A.; Khaymovich, Ivan; Ala-Nissila, T.; Pekola, JukkaWe present an experimental realization of an autonomous Maxwell’s demon, which extracts microscopic information from a system and reduces its entropy by applying feedback. It is based on two capacitively coupled single-electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the demon and the system as well as their mutual information exchange. The operation of the demon is directly observed as a temperature drop in the system. We also observe a simultaneous temperature rise in the demon arising from the thermodynamic cost of generating the mutual information. - Quantum jump model for a system with a finite-size environment
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2016-06-03) Suomela, S.; Kutvonen, A.; Ala-Nissilä, TapioMeasuring the thermodynamic properties of open quantum systems poses a major challenge. A calorimetric detection has been proposed as a feasible experimental scheme to measure work and fluctuation relations in open quantum systems. However, the detection requires a finite size for the environment, which influences the system dynamics. This process cannot be modeled with the standard stochastic approaches. We develop a quantum jump model suitable for systems coupled to a finite-size environment. We use the method to study the common fluctuation relations and prove that they are satisfied.