@misc{10481/102758,
year = {2025},
month = {2},
url = {https://hdl.handle.net/10481/102758},
abstract = {The efficiency of any heat engine, defined as the ratio of average work output to heat input, is bounded
by Carnot’s celebrated result. However, this measure is insufficient to characterize the properties of
miniaturized heat engines carrying non-negligible fluctuations, and a study of higher-order statistics of
their energy exchanges is required. Here, wegeneralize Carnot’s result for reversible cycles to arbitrary
order moment of the work and heat fluctuations. Our results show that, in the quasistatic limit, higherorder
statistics of a small engine’s energetics depend solely on the ratio between the temperatures of
the thermal baths. We further prove that our result for the second moment gives universal bounds for
the ratio between the variances of work and heat for quasistatic cycles. We test this theory with our
previous experimental results of a Brownian Carnot engine and observe the consistency between
them, even beyond the quasistatic regime. Our results can be exploited in the design of thermal
nanomachines to reduce their fluctuations of work output without marginalizing its average value and
efficiency.},
organization = {NSF of China
(Grant Nos. 12375039, 11975199, and 11674283)},
organization = {Zhejiang Provincial
Natural Science Foundation Key Project (Grant No. LZ19A050001)},
organization = {Fundamental Research Funds for the Central Universities (2017QNA3005,
2018QNA3004)},
organization = {MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) (Grant Nos.
JPMXS0118067394 and JPMXS0120319794},
organization = {MSCA-IF NEQLIQ-101030465},
organization = {PNRR MUR project PE0000023-NQSTI},
publisher = {Springer},
title = {Universal relations and bounds for fluctuations in quasistatic small heat engines},
doi = {10.1038/s42005-025-01961-1},
author = {Ito, Kosuke and Xu, Guo-Hua and Jiang, Chao and Roldán, Edgar and Rica Alarcón, Raúl Alberto and Martínez, Ignacio A. and Watanabe, Gentaro},
}