QFT is a three-letter abbreviation with multiple meanings, as described below:
* quantitative feedback theory.
* quantum field theory, an application of quantum mechanics.
* the quantum Fourier transform, a discrete Fourier transform.
* Queen's Film Theatre, a cinema in Northern Ireland.
* "QFT", internet slang meaning "quoted for truth". This term usually applies when a message is repeated for emphasis. It is also quite often used to mean "quit fucking talking", which can cause confusion.