How many photons does it take to form an image? Can we form images of an object without interacting with it? Is it possible to illuminate an object with one light source and see an image with another?

How many pixels do we need to form a high resolution image of an object? Can we do it with just one?

Taking a picture would appear to be a straightforward affair. One shines light onto an object, that light gets reflected into a detector, and (perhaps after some amplification) gets mapped to pixels which form a two-dimensional representation of the object. And clearly, the more pixels our camera has, the better the resolution, right?

Actually, quantum optics research over the past few years has led to a new technique, known as "ghost imaging", in which the light forming the image has never actually
interacted with the object being imaged. How can this be possible and why is it useful?

In tonight's session of Science & Cocktails we will explore, together with Andrew Forbes, how the use of quantum entanglement, the spooky action at a distance so abhorred by Einstein, allows us to break our paradigms as to what is possible and what is not when it comes to forming images of objects. Andrew Forbes will guide us through some of the ghost imaging research that he and his colleagues within the Wits Structured Light Laboratory have been doing, and explain what benefits and applications this exciting technique is expected to lead to in the near future.

Afterwards, spooky cocktails will bring us closer to the quantum world while Rhapsody take the stage with their eclectic mix of contemporary, jazz and traditional South African sounds.

Image: Experimental ghost image with entangled light (Courtesy of Andrew Forbes/Structured Light Laboratory)