Talk:Fredkin gate

Image

The image of the example circuit has several problems, among them:

• the connections on the left are unclear
• the circuit is not reversible because it uses fanouts

89.204.130.224 (talk) 20:34, 17 June 2013 (UTC)

I replaced the example circuit. The new one uses only five gates and is reversible (no fanouts), and the connections in the image are clear. — Preceding unsigned comment added by 2001:4898:80E8:2:0:0:0:12 (talk) 22:41, 15 December 2016 (UTC)

This image is still unclear. What do the dots, lines, and x's represent? Zylstra (talk) 20:22, 27 February 2018 (UTC)

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When?

It seems like the Fredkin gate was invented in 1974 or 1975, based on the book in the first reference: Brown, Julian, The Quest for the Quantum Computer, New York : Touchstone, 2000.

1. Page 60, last paragraph: "In 1974 Fredkin took a year off from MIT to spend time at Caltech working with Feynman."
2. Page 61, The Fredkin Gate: "During his time at Caltech [...] he found a way of constructing logic gates that could work reversibly. [...] The key to Fredkin's vision was a new kind of device that became known as the Fredkin gate."

I don't know if that'd be considered original research, but hopefully it helps someone else who was curious like I was. 2600:8800:7900:1A9:10DA:E4CE:5E54:DA9C (talk) 18:14, 20 July 2019 (UTC)