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Carnot Cycle at Finite Power and Attainability of Maximal Efficiency Armen Allahverdyan

Carnot Cycle at Finite Power and Attainability of Maximal Efficiency Armen Allahverdyan (Yerevan Physics Institute ) -- Introduction: heat engines, Carnot cycle -- Non-equilibrium Carnot cycle -- Analysis: PRL 2013. -- Coauthors: Karen Hovhannisyan,

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Carnot Cycle at Finite Power and Attainability of Maximal Efficiency Armen Allahverdyan

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  1. Carnot Cycle at Finite Power and Attainability of Maximal Efficiency Armen Allahverdyan (Yerevan Physics Institute) -- Introduction: heat engines, Carnot cycle -- Non-equilibrium Carnot cycle -- Analysis: PRL 2013. -- Coauthors: Karen Hovhannisyan, S. Gevorkian, A. Melkikh

  2. Work-source Hot bath Cold bath Cyclic engine Power: Work: output / input Efficiency: Challenge: to make engines both powerful and efficient B. Andresen, Angew Chem '11 U. Seifert, Rep. Prog. Phys. '12 Benenti, Casati, Prosen, Saito, arxiv:1311.4430

  3. Carnot cycle: useless in practice: 4 times slow Thermally isolated and slow Isothermal and slow Carnot = maximal efficiency

  4. Non-equilibrium Carnot cycle Engine: density matrix and Hamiltonian

  5. Work-source and baths act separately  easy to derive work and heat Maximize W over dynamics n+1 energy levels and the temperatures are fixed

  6. Sudden changes are optimal n degenerate states: energy concentration optimized energy gaps

  7. Work and efficiency n>>1 number of levels ln n >>1 number of particles Relaxation time ? Realistic Ad hoc: system-bath (interaction) Hamiltonian is fine-tuned to system Hamiltonian

  8. An example of fine-tuned system-bath Hamiltonian bath: 2-level systems there is

  9. works for any realistic Unstructured data-base search (computationally complex) Grover, PRL '97 Power  zero Farhi, Gutman, PRA '98 Vogl, Schaller, Brandes, PRA'10

  10. ReduceW,resolve the degeneracy Levinthal’s problem for protein folding Zwanzig, PNAS '95

  11. Conclusions The reason of not reaching Carnot efficiencyfor realistic system-bath interaction is computational complexity Protein models as sub-optimal Carnot engine Non-reachability of Carnot efficiency at a large power is not a law of nature: there is a fine-tuned interaction that achieves this.

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