State tomography using weak continuous quantum measurements
By Shoumik Chowdhury
Although I began studying physics at school in the 7th grade, my interest in the subject came largely from reading popular science books. One such book was called Einstein for Everyone; a slim volume, it provided a non-technical rundown of all of the major areas in modern physics, from atomic physics all the way up' to cosmology. I was particularly intrigued with the book's description of quantum mechanics --- the thought of Schrodinger’s cat’ being both alive and dead simultaneously was fascinating to me, as was the notion that measuring something could change the outcome … In quantum mechanics, the state of a system can be fully represented by its wave function. Knowledge of the wave function of a quantum system serves as a direct means to predict the outcome of a measurement on an observable of that system. The ability to accurately determine the wave function of a possibly unknown quantum state is, therefore, of fundamental importance…