### Abstract

In a stochastic heat engine driven by a cyclic non-equilibrium protocol, fluctuations in work and heat give rise to a fluctuating efficiency. Using computer simulations and tools from large deviation theory, we have examined these fluctuations in detail for a model two-state engine. We find in general that the form of efficiency probability distributions is similar to those described by Verley et al (2014 Nat. Commun. 5 4721), in particular featuring a local minimum in the long-time limit. In contrast to the time-symmetric engine protocols studied previously, however, this minimum need not occur at the value characteristic of a reversible Carnot engine. Furthermore, while the local minimum may reside at the global minimum of a large deviation rate function, it does not generally correspond to the least likely efficiency measured over finite time. We introduce a general approximation for the finite-time efficiency distribution, , based on large deviation statistics of work and heat, that remains very accurate even when deviates significantly from its large deviation form.

Original language | English (US) |
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Article number | 102003 |

Journal | New Journal of Physics |

Volume | 16 |

DOIs | |

State | Published - Oct 24 2014 |

### Keywords

- Large deviations in non-equilibrium systems
- Molecular motors
- Non-equilibrium fluctuations in small systems

### ASJC Scopus subject areas

- Physics and Astronomy(all)

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## Cite this

*New Journal of Physics*,

*16*, [102003]. https://doi.org/10.1088/1367-2630/16/10/102003