Ciro Santilli @cirosantilli  40

Most notable example: gallium arsenide, see also: gallium arsenide vs silicon.

An important class of semiconductors, e.g. there is a dedicated III-V lab at: École Polytechnique: www.3-5lab.fr/contactus.php

TODO WTF is this? How is it built? What is special about it?

Mentioned a lot in the context of superconducting quantum computers, e.g. youtu.be/t5nxusm_Umk?t=268 from Video "Quantum Computing with Superconducting Qubits by Alexandre Blais (2012)",

A Turing machine that simulates another Turing machine/input pair that has been encoded as a string.

In other words: an emulator!

The concept is fundamental to state several key results in computer science, notably the halting problem.

A computer model that is as powerful as the most powerful computer model we have: Turing machine!

When it distributes it inverts the order of the matrix multiplication:

The transpose and matrix inverse commute:

The first working one in 1947 by John Bardeen and walter Brattain in Bell Labs Murray Hill.

People had already patented a lot of stuff before without being able to make them work. Nonsense.

As the name suggests, this is not very sturdy, and was quickly replaced by bipolar junction transistor.

By William Shockley in 1948 also at Bell Labs Murray Hill.

As of 2020, not used anymore in logic gates, but still used in amplifiers.

One of Ciro Santilli's favorites.