Turing Complete Fredkin Gate? (CSWAP)

Introduction

Fredkin Gate, also known as the "conservative logic gate" or "CSWAP gate", is a computational circuit suitable for reversible computing, invented by Edward Fredkin. It is currently used in quantum computers due to its unique property of not losing information (energy) during data processing. It functions similarly to a 4-way light switch, as far as I know.

To be honest, I have no idea what I'm talking about. Ha ha.

The TRUE purpose of this guide is to provide an open platform for everyone to discuss the Fredkin Gate, and document our combined knowledge of it. I plan to update this guide periodically and fill in any missing blanks. But in the meantime, feel free to leave your comment!

Circuitry

^ This is (probably?) how a Frankin Gate should be implemented. If the control input is OFF, the input-output pairs run parallel (i1 --> o1, i2 --> o2); If the control input is ON, the input-output pairs get swapped (i1 --> o2, i2 --> o1).

Assuming no energy is lost in the wires and switches (i.e. Quantum Computers), the outputs can always be reverse-engineered to figure out the original inputs. Hence, no information (energy) is lost in the process.

Note that having the NOT Gate here kinda defeated this whole purpose of retaining energy, but this is because there aren't any normally ON switches in the game.

AND Gate

I have no idea how to do that... I need time to do more research :3

You can help me out too!

References

Reddit Discussion:

https://www.reddit.com/r/TuringComplete/comments/xh49cm/does_anyone_know_how_to_build_with_cswap/

"Conservative Logic"

by Edward Fredkin, Tommaso Toffoli

https://web.cecs.pdx.edu/~mperkows/temp/June16/ConservativeLogic.pdf

"CSwapGate"

by Qiskit

https://qiskit.org/documentation/stubs/qiskit.circuit.library.CSwapGate.html

"cirq.CSWAP"

by Google Quantum AI

https://quantumai.google/reference/python/cirq/CSWAP

"A Quantum Computer Simulator"

by Carsten Urbach

https://rdrr.io/cran/qsimulatR/

https://rdrr.io/cran/qsimulatR/man/cswapgate.html

"Computing Limit"

by Computerphile

https://www.youtube.com/watch?v=jv2H9fp9dT8

"Fredkin Gate implemented in shapez.io"

by John Meacham

https://www.youtube.com/watch?v=CySN31YrR2U

"What's Inside A 3-way and 4-way Switch?"

by Electrician U

https://www.youtube.com/watch?v=5NfjfhA8zdo

"Quantum Computing Closer After Scientists Build a Fredkin Gate"

by Jelor Gallego

https://futurism.com/quantum-computing-closer-scientists-build-fredkin-gate

"A quantum Fredkin gate"

by Raj B. Patel, Joseph Ho, Franck Ferreyrol, Timothy C. Ralph, Geoff J. Pryde

https://www.science.org/doi/10.1126/sciadv.1501531

"Why are reversible gates not used?"

by Mehdi

https://cs.stackexchange.com/questions/38049/why-are-reversible-gates-not-used

Wikipedia:

https://en.wikipedia.org/wiki/Fredkin_gate

^ never put this in the reference section!

Translations :)

Source: https://steamcommunity.com/sharedfiles/filedetails/?id=2864418961

Fredkin Gate? (CSWAP)

Introduction

Circuitry

AND Gate

References

Translations :)

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