The Smallest Thermal Machines

The Smallest Thermal Machines

Are there limits to how small one can make a thermodynamic machine? At first sight, this question appears to contradict itself, as thermodynamics usually begins with a kind of macroscopic picture. However, as Nicolas Brunner at the University of Bristol, UK, and colleagues describe in a paper appearing in Physical Review E, this constraint can be circumvented, if one focuses on a special kind o...

How small can thermal machines be? The smallest possible refrigerator.

We investigate the fundamental dimensional limits to thermodynamic machines. In particular, we show that it is possible to construct self-contained refrigerators (i.e., not requiring external sources of work) consisting of only a small number of qubits and/or qutrits. We present three different models, consisting of two qubits, a qubit and a qutrit with nearest-neighbor interactions, and a sing...

Selecting the Smallest Extreme Value Population with the Smallest Variance

The Generalized Smallest Grammar Problem The Generalized Smallest Grammar Problem

The Smallest Grammar Problem – the problem of finding the smallest context-free grammar that generates exactly one given sequence – has never been successfully applied to grammatical inference. We investigate the reasons and propose an extended formulation that seeks to minimize non-recursive grammars, instead of straight-line programs. In addition, we provide very efficient algorithms that app...

An Algorithm for Finding the Smallest Set of Smallest Rings

This paper describes an algorithm which finds the smallest set of smallest rings of a ring system without the necessity of finding all rings in the ring system. The algorithm first finds the smallest rings in which unused atoms occur and then progresses to find the smallest rings in which unused edges and faces occur until the smallest set of rings required to describe the complete ring system ...