Welcome | नमस्ते | ਸਤਿ ਸ੍ਰੀ ਅਕਾਲ

We are a research group at IIT Ropar carrying out experimental and theoretical research in quantum optics – an area of physics that focuses on the fundamental properties of light.

Our understanding of light continues to develop through a fascinating interplay of experimental discoveries and theoretical abstractions that spans many centuries. In early times, light was imagined to consist of particles that travel in straight lines or rays. This particle abstraction is adequate for describing simple effects such as reflection from a mirror and refraction in lenses. However, it was later discovered that this abstraction fails at describing certain effects such as the fantastic colorful patterns visible when a layer of petrol floats on water. As a result, it was then proposed that light should be imagined as a wave that can overlap with itself to produce such patterns, much in the same way that water waves overlap to produce ripple patterns on a pond. This wave abstraction turns out to work remarkably well for describing most effects that are commonly observed with light. However, even this abstraction was later found to have limitations. For instance, experiments showed that when the brightness of light is gradually reduced, one eventually finds that light is not really smooth and continuous like waves, but is instead grainy and discrete like a train of particles. Essentially, it was realized that neither the particle abstraction nor the wave abstraction is sufficient by itself because some aspects of light are particle-like and some are wave-like. In order to capture both these complementary aspects of light simultaneously, a complex mathematical recipe known as quantum theory was developed. This recipe correctly predicts the statistical results of every experiment done with light till date, but it suffers from interpretation ambiguities and formal consistency problems. So the search for new experimental discoveries and better theoretical abstractions continues to this day. We are excited and grateful to have the opportunity to participate in our own small way in this global human pursuit.

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