Research Description For A Broad Audience
The focus of my postdoctoral research is based on the development of basic building blocks of quantum computers which are expected to be much faster and efficient compared to the present days computers (classical computers). The realization of a large-scale quantum computer is a long term goal and currently physicist, computer scientists, mathematicians and engineers are working on a variety of unsolved problems both in theoretical and experimental frontiers. The classical computers store and process information using a series of binary numbers, bits, represented by either a 0 or a 1. Quantum computers can store and process information using qubits (contraction of the words "quantum" and "bits"), which can be represented by "both" 0 and 1. There are many different physical systems which can serve as qubits, but the internal states of an ion (a charged atom) have been shown to be an system. Many many ions can be stored very close to each other in a very controllable way (the qubits must be well isolated from the environment and the interaction between qubits must be very strong) to realize a quantum computer. I am working with a handful of these ions using a device called ion trap, where ions can be stored for a long time and qubit interactions can be investigated using lasers and microwaves.
There are four fundamental forces in nature, 1) the gravitational force which is
experienced by anything that has a mass, 2) the electromagnetic force which is
experienced by anything that has a charge, 3) the strong force which exists inside
the nucleus, 4) the weak force which also exists inside the nucleus. By
combining all the four fundamental forces of nature except gravity, physicists have
developed the Standard Model, the most successful theoretical framework so far, which
allows us to describe all confirmed experimental observations till date. However
the model does not provide a physical explanation to a number of experimental facts,
such as the breaking of mirror symmetry (a fundamental symmetry of nature) in weak
interaction and there are many more. Several speculative theoretical models have been invented to describe such open and
unanswered questions, but they have not standing in physics unless they are verified
The experimental verification is done at different energy scales, namely the high, medium or low energy at which the measurement is done. I had developed a low energy experimental set up to understand and investigate the breaking of mirror symmetry in weak interaction. The system I chose is radium ion, because theoretically radium ion has been shown to have the biggest mirror symmetry breaking effects. A single radium ion is held in space by applying electric forces. By shining light (from a number of lasers) onto it, different properties of its internal states are very precisely measured. Further experimental work is in progress towards the precision measurement of mirror symmetry breaking, the so called parity violation.
When a ray of light strikes on something a part of light returns back. This change in direction of light is known as reflection. Reflection is sometimes useful in day to day life, such as the reflection of our face from a bathroom mirror. But in physics experiments involving light some reflections are extremely unwanted. For example reflected light going back to the light source make the source unstable and sometimes destroys it. An optical isolator is something that prevents most of the back reflected light. But the commercial isolators are very big (hence heavy) and are also very expensive. Hence the motivation comes to make these isolators small and cost effective. I made a film type isolator where a very thin layer of a smart material (the so called magnetic garnets) has the capability to prevent the back reflected light. Using a technique called "sputtering" thin films of magnetic garnets are made on a substrate (which holds the thin film) and thickness of the film is carefully engineered such that it can prevent most or all of the back reflected light. When multiple layers or films are made of two different garnet materials, it works as a photonic crystal with immense application in industrial and fundamental physics research.