# Second Law based definition of passivity/activity of devices

## TL;DR

This paper introduces a new definition of passivity and activity for devices based on the Second Law of Thermodynamics, challenging traditional engineering concepts and analyzing devices like memristors within thermodynamic systems.

## Contribution

It proposes a thermodynamics-based, self-consistent definition of passivity/activity, revealing contradictions in engineering definitions when noise is present, and analyzing rectifier circuits in thermal noise contexts.

## Key findings

- Engineering definitions are self-contradictory with Johnson-Nyquist noise.
- A new thermodynamic definition clarifies device activity.
- Rectifiers that rectify thermal noise must contain active elements.

## Abstract

Recently, our efforts to clarify the old question, if a memristor is a passive or active device [1], triggered debates between engineers, who have had advanced definitions of passivity/activity of devices, and physicists with significantly different views about this seemingly simple question. This debate triggered our efforts to test the well-known engineering concepts about passivity/activity in a deeper way, challenging them by statistical physics. It is shown that the advanced engineering definition of passivity/activity of devices is self-contradictory when a thermodynamical system executing Johnson-Nyquist noise is present. A new, statistical physical, self-consistent definition based on the Second Law of Thermodynamics is introduced. It is also shown that, in a system with uniform temperature distribution, any rectifier circuitry that can rectify thermal noise must contain an active circuit element, according to both the engineering and statistical physical definitions.

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Source: https://tomesphere.com/paper/1705.08750