Physicists Alain Aspect, John Clauser and Anton Zeilinger were awarded the Nobel Prize in Physics this week for pioneering quantum entanglement experiments.
Quantum entanglement is a phenomenon where a group of particles share a quantum state, even if they are physically separated by some distance. Measuring the momentum, spin or polarization of a particle affects and immediately determines the state of other entangled particles in the same system.
The nature of entanglement has been hotly debated among physicists. Some thought information couldn’t travel faster than light and there must be some other process affecting the particles in the system, while others believed the strange phenomena showed a breakdown in classical physics and paved the way for quantum mechanics.
In 1964, John Stewart Bell developed a theoretical framework that tests whether the entanglement effects are due to some hidden variables affecting the entangled particles. Bell’s inequalities describe the mathematical constraints that an entangled system must obey when affected by these local hidden variables.
The trio of tinkerers who bagged the Nobel Prize in Physics this week did so, we’re told, “for experiments with entangled photons, to demonstrate violations of Bell’s inequalities, and for pioneering work in quantum information science.” That is, they proved that quantum entanglement is an inherent property of particles; that hidden variables do not affect the measurement result.
From left: Alain Aspect, John Clauser and Anton Zeilinger… Photo credit: Niklas Elmehed © Nobel Prize Outreach
Clauser, 79, and Aspect, 75, performed the first experiments proving that entangled particles violate Bell’s inequalities in separate projects conducted in the US and France. Zeilinger, 77, later applied the results to other experiments that demonstrated other entanglement-related effects, such as quantum teleportation of a qubit.
“It is becoming increasingly clear that a new type of quantum technology is emerging,” said Anders Irbäck, chairman of the Nobel Committee for Physics, on Tuesday. “We see that the work of the laureates with entangled states is of great importance, even beyond the fundamental questions about the interpretation of quantum mechanics.”
Meanwhile, the Nobel Prize in Physiology was awarded to Swede Svante Pääbo “for his discoveries on the genomes of extinct hominins and human evolution.” The evolutionary geneticist sequenced the genomes of Neanderthals and used DNA analysis to discover Denisovans, another ancient human ancestor species.
He showed that genes passed between these hominins when they migrated from Africa 70,000 years ago influenced the biological functions of modern-day Homo sapiens, such as how our immune system defends itself against infection.
Pääbo, 67, will win the Nobel Prize in Physiology for a total of ten million Swedish kroner, worth over US$900,000 or £800,000, while Aspect, Clauser and Zeilinger will share the same amount for the Nobel Prize in Physics equally. ®