Facts and myths about zero-point thermal noise, and information entropy versus thermal entropy

• In this talk, we are briefly surveying our recent results [1-3] about two very popular yet often misunderstood concepts in physical informatics: (i) The existence of Johnson noise at near to absolute zero temperature has been debated many times yet it is generally accepted [1]. We point out the fundamental problems [2] with the particular approach the related quantum theories [4] of Fluctuation-Dissipation Theorem are using. Then we prove that the existence of zero-point noise would allow the construction of a perpetual motion machine [1]. Finally, we cite early works pointing out that the observed “zeropoint” noise in experiments [7] with phase-sensitive linear amplifiers is an amplifier-noise [5,6] due to the uncertainty principle, and it does not exist in the resistor in an objective way, independently from the measurement [1,2]. Thus a correct derivation of the Fluctuation-Dissipation Theorem must include [1] the type of experimental setup used for the measurement. (ii) The general opinion is that information entropy and thermal entropy are interchangeable. This belief triggered Brillouin's negentropy principle of information [8], and Landauer's claimed principle [9] about energy dissipation during information erasure that has been debated on many occasions [10-19]. Here we show the newest and perhaps the simplest arguments [3] proving that the two types of entropies are apples and oranges and are not interchangeable.

Subject headings

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Keyword

Second Law

noise

measurements

entropy

information

Publication and Content Type

ref (subject category)

kon (subject category)