Grover’s Algorithm
One of my earliest glimpses of quantum computing was in an article about Grover’s algorithm. I read the article several times. I understood the mechanics of Grover’s algorithm but not the big picture behind it. When you run the algorithm, you start with some qubits, and you change their states. After some amount of fiddling, you measure the system, and (with high probability) the correct answer appears before your eyes! Is this a real algorithm, or is it merely sleight of hand?
Several weeks later, during an hour-long train ride, I scribbled some calculations and convinced myself that the algorithm was destined to work.
The algorithm was originally published in an article entitled A fast quantum mechanical algorithm for database search. So, many months later, when I gave a lecture about Grover’s algorithm, I told students the algorithm was useful for searching through database records. One of the students asked me how database tables...
