Continued Summer REU Ideas

Published on: Wed Jun 01 2011

One of the books I was reading makes quite a big deal about entanglement. The opening question in the book is “What is Entanglement?”. The book is talking about how entanglement is used as a resource for QCQI.

I tried googling various things:

  1. ·      entanglement as a resource

  2. ·      entangled photon source

  3. ·      spontaneous parametric down-conversion

  4. ·      how to detect a photon

These topics have led me to a source I have read through many times, Colgate University undergraduate experiments in quantum mechanics. I would like to try out Lab 5, Entanglement and Bell. Putting together the set up for creating entangled photons and detecting them is quite interesting. Once I have a set up capable of producing a single photon then creating an entangled pair and finally detecting them, I could do other things. The book’s I have been reading on Quantum Information are regularly referring to entangled states.

The apparatus

There are three main components, a laser, an avalanche photodiodes for detecting single photons and a BBO crystal. The main trouble is probably going to be in the detection of a single photon. I was thinking of this and suddenly realized, how do I know I’m looking at one photon only? The entire process of detecting a single photon is based on the photoelectric effect, E = hv – phi. And an avalanche photodiode works by a single photon knocking off a single electron which in turns sets off more electrons producing a noticeable current.