The concept of a quantum bit, or qubit, as a fundamental unit of information in quantum computing, was proposed by the physicist Benioff in 1980. He described the idea of using quantum systems as a basis for computational operations and introduced the notion of a quantum mechanical version of a classical bit.
However, it was the physicist and mathematician Paul Benioff who first introduced the concept of a quantum bit and its potential for quantum computing. In his seminal paper titled "The Computer as a Physical System: A Microscopic Quantum Mechanical Hamiltonian Model of Computers as Represented by Turing Machines," published in 1980, Benioff proposed the use of quantum systems to perform computational tasks.
It's important to note that while Benioff introduced the concept of the qubit, the subsequent development and implementation of quantum computing technologies involved the contributions of several other scientists, including Peter Shor, who formulated quantum algorithms, and others who made significant advancements in the field.