For over 100 years, quantum physics has taught us that light is both a wave and a particle. Now, researchers at the Massachusetts Institute of Technology (MIT) have performed a daring experiment using single atoms that confirms that, while light can behave as either a particle or a photon, it cannot be seen to behave as both at the same time.
The debate about the nature of light goes back centuries, to the 17th century and the time of Isaac Newton and Christiaan Huygens. Some, like Newton, believed that light had to be made from particles to explain why mirror images are sharp and our inability to see around corners. And yet, Huygens and others pointed out, light exhibits wave-like behavior, such as diffraction and refraction.
