University of Calgary

A peek into the quantum world of light

UToday HomeApril 16, 2012

Photo credit: Jean-François DarsWorld-renowned French physicist, Alain Aspect, is giving the Institute for Quantum Information Science (IQIS) annual lecture April 26. Photo credit: Jean-François DarsCan you be at two places at the same time, for instance at work and at the elementary school to pick up your kids? No, even if sometimes you wish you could. But, according to Alain Aspect, a world-renowned French physicist, a photon (a quantum particle of light) can.

Alain Aspect, Augustin Fresnel Professor and CNRS senior scientist at the Institut d'Optique and professor at the Ecole Polytechnique, in Palaiseau (near Paris), will give the annual public lecture of the university’s Institute for Quantum Information Science (IQIS) April 26.

Alain Aspect was born in Agen, France. He has pioneered the development of the foundations of quantum physics, and is internationally acclaimed for his groundbreaking experimental work that demonstrated the often mind-boggling behavior of particles of light. His work has been recognized through many awards, including the 2010 Wolf Prize in Physics, which is considered one of the world’s top scientific awards. In addition, he will receive the Albert Einstein medal in May 2012.

“Aspect’s work has established some of the most important concepts of quantum physics,” says University of Calgary associate professor Wolfgang Tittel. “His papers were among the first I studied when I started graduate work back in 1994, and their importance is unchanged today.”

Professor Barry Sanders, the director of IQIS, adds: “We are very pleased to host Alain Aspect for this lecture. His findings are explored nowadays by members of our institute to enable applications such as quantum computing and quantum cryptography.”

Alain Aspect’s presentation will take place April 26 from 7-8 p.m. in the ICT102 Lecture Room.

His presentation will focus on interference, a phenomenon that we know well from splitting a water wave and recombining the two pieces after they have traveled along different paths, which may lead to an enhanced or decreased wave.

Surprisingly, the same phenomenon can be observed when using individual and indivisible particles of light. Hence, the photon must have been in both paths at the same time—like you being simultaneously at work and at school.

Admission to the lecture is free, but advance registration is required at