When I was still a boy, maybe 7 or 8 years old, I looked in the mirror and pondered on what seems obvious at first: the reflection I saw changed as I moved around. I asked myself: how can the mirror deal with all these different reflections? Does it reflect one, then the other, or is it reflecting all of them simultaneously?
As far as I can remember, that is probably the very first physics question I asked myself. Not knowing what light and mirrors really are, I could not find the answer, and nobody in my entourage could either … but I did not forget about it.
I think that understanding what light is, and what we can do with it, has always been part of my motivation to follow one research direction or another. Light pervades us, it puts everything in touch, close or remote. It allows me to see my kids grow into little persons. It allows us to observe the universe as it was more than four billion years ago. I find this fascinating: light is a universal messenger.
The International Year of Light and Light-based Technologies 2015 (IYL 2015) involves artists and scientists across a large range of domains. It certainly also involves astronomers and to honour this year, we might temporarily rename our research groups Laboratories of Light Pathology. Astronomers analyse light in order to understand the formation, evolution and subsequent fate of celestial bodies. While though this sounds obvious today, it seemed inconceivable in the past. 180 years ago, the French philosopher Auguste Comte argued that we would never be able to determine the chemical or mineralogical structure of planets other than Earth since we couldn’t obtain geological samples (1). Nowadays our improved understanding of light-matter interactions allows precise analyses of planetary, stellar and inter-stellar compositions.
M33, the Triangulum Galaxy. Credit: Robert Gendler, Subaru Telescope (NAOJ). Image data: Subaru Telescope, Robert Gendler, Brigham Young University Obs., Johannes Schedler. http://apod.nasa.gov/apod/ap121220.html
Cyber security is an increasingly complex issue and a growing concern worldwide. As our utilization of communication technology increases, so to do the means used by cyber intruders to infiltrate networks to access sensitive information or damage infrastructure. The cornerstone of secure communications is the cryptographic keys. As the varying heights of a door key’s cuts can keep a door locked, a varying numerical sequence – or random number sequence – can be used to keep a data message locked. Everything from secure email and online banking to keeping our modern power-grids and satellites safe relies on these data keys.
It was a sunny day in August 2013 when my friend Margherita and I decided that my PhD thesis on ‘Generation and manipulation of multiphoton quantum states of light’ could be an interesting dance subject.
Our aim was to participate in the ‘Dance your PhD’ contest. The summer heat and the clear Liguria Sea in front of us provided the right inspiration. I began to tell Margherita what my thesis was about. For three years, I had used light — specifically, the fundamental particle of the electromagnetic field, the photon — in order to explore the transition from the microscopic to the macroscopic world. To enlighten this micro-macro transition, I started with a funny story: the Schröedinger’s cat paradox.
Schoredinger’s cat paradox. Credits: Andrea Parisi