# Entropic Quantum Machine

## TL;DR

This paper introduces entropic quantum machines (EQMs), nanomachines that leverage both entropic and quantum effects to produce switchable functions, with a systematic design protocol and a practical example demonstrating shape-shifting behavior.

## Contribution

It presents a new class of nanomachines called EQMs, along with a systematic design protocol and an illustrative example with switchable shapes.

## Key findings

- Designed a novel EQM with two characteristic shapes
- Demonstrated shape switching via temperature or external field
- Provided a systematic protocol for EQM design

## Abstract

We study nanomachines whose relevant (effective) degrees of freedom f >> 1 but smaller than f of proteins. In these machines, both the entropic and the quantum effects over the whole system play the essential roles in producing nontrivial functions. We therefore call them entropic quantum machines (EQMs). We propose a systematic protocol for designing the EQMs, which enables a rough sketch, accurate design of equilibrium states, and accurate estimate of response time. As an illustration, we design a novel EQM, which shows two characteristic shapes. One can switch from one shape to the other by changing temperature or by applying a pulsed external field. We discuss two potential applications of this example of an EQM.