The history of the field of quantum information science

Quantum information science relies on physics, mathematics, computer science and engineering to understand how to process data in ways that were not even foreseen by the founding fathers of the current information revolution, says Prof. Charles Bennett, IBM Fellow and 2018 Wolf Prize Winner in Physics

By Charles Bennett, Fellow IBM and 2018 Wolf Prize Winner in Physics

Quantum information science draws on physics, mathematics, computer science and engineering to understand how to process data in ways that were never foreseen by the founding fathers of the current information revolution. The roots of the field are planted in the 70's of the last century, when a series of pioneers such as Stefan Weisner from Columbia University, Rolf Landauer and Anochy at IBM, David Deutsch at Oxford and Nobel laureate Richard Feynman at Caltech, began to introduce fundamental questions such as "how much energy required to process a single bit of information?", or "Could the quantum effect help, instead of being an obstacle, in data processing?"

At the time, the few people who thought about these issues operated in isolation: no one thought of the field as their full-time job. Eventually, however, many of us met each other and were inspired at the first Physics of Computing Conference, held at MIT in 1981. There, I presented my findings from 1973, in a study inspired by Landauer's work, in which I stated that there is no fundamental inherent limit , irreducible further, which concerns the energetic cost of performing a calculation operation. In other words: it is possible to perform calculations in a format that preserves the possibility of a complete thermodynamic reversal: a transition between two states without a total loss of energy. At the same conference, Feynman also presented his thesis that in order for a computer to be able to perform an effective simulation of nature - it must operate within the framework of quantum laws, and not within the framework of classical computing laws.

As part of the conference at MIT and other conferences organized by cosmologist John Wheeler, at the University of Texas, these ideas began to be disseminated to the growing community of physicists who were interested in the field. Gilles Brassard from the University of Montreal followed first, bringing the idea to the world of computer science.

Most computer scientists were initially reluctant to accept the idea of ​​quantum information, in the mistaken belief that they already knew everything about data processing. As such, the idea of ​​quantum computing was first defined by a physicist: David Deutsch, who attended Wheeler's conference. Thus, the match between quantum mechanics and classical theory in the field of computing began, and the field of quantum information science was born.

In 1984, Brassard and I developed the quantum cryptographic structure BB84, which enables secure communication between parties that are not required to share secret information first. Five years later, John Sumlin, then an undergraduate student at MIT and later at IBM, along with me, built the hardware for the first working demonstration of quantum encryption. The hardware, which ran under software written by Brassard and his students in Montreal, implemented the BB84 protocol, which until then existed only on paper.

In 1993, Brassard and I, together with the computer scientist Claude Carpeau, the mathematician Richard Jossa, and the physicists Asher Peres and William Waters, discovered "quantum teleportation": a method of separating and splitting an unknown quantum state into two parts: a part Classical and partly non-classical, in the form of quantum entanglement. These two parts are sent in separate channels, and reassembled later on the receiving side - in order to create an exact replica of the original quantum state, which was destroyed and lost in the sending process.

The discovery reached in 1994 by Peter Shore, at Bell Laboratories, according to which a quantum computer could exponentially speed up the solution of the practical problem of factoring a number into whole factors ignited worldwide interest in the new field. In the meantime, scientific work at IBM, Bell Laboratories and other institutions presented a series of technologies for the reliable transmission of quantum information even in noisy channels, and the possibility of reliable quantum computing on unreliable hardware - which are essential for the practical application of quantum computing, and not just on paper.

As with any field of basic science, it is currently difficult to predict the long-term effects of quantum information science, but experts hope that it will have a profound impact on the fields of artificial intelligence, molecular modeling and building new molecules, online security, financial modeling and particle physics. I am proud of the contribution of my work with Professor Brassard, to the laying of the foundations for quantum information science, and believe that it embodies the spirit of the Wolf Prize: "Achievements for the benefit of the human race and the bonds between human beings... regardless of nationality, race, color, religious belief, sex or beliefs the politics".

More of the topic in Hayadan:

• "With the help of the insight we received from decoding the genome of the bees, we will be able to fight the collapse of the beehives" (Interview with Prof. Gene Robinson, winner of the 2018 Wolf Prize for Agriculture)
• Israel will invest in a quantum computing system for security issues
• The national program for quantum computing is essential for Israel to remain at the forefront of science and technology
• A system for the discovery of a single atom - for use in quantum computing