Brass tacks

Therefore, the issue at hand is whether or not the experiment can be carried out effectively.The Rochester researchers did it with two photons, but it is more difficult to get multiple photons to a complete sequence of beam splitters at the right time.According to Barry Sanders, director of the Institute for Quantum Information Science at the University of Calgary, “it’s challenging, technologically, but not forbiddingly so.”Sanders points out that when the Rochester researchers conducted their initial experiment in 1987, they used lasers mounted on lab tables to send photons simultaneously down fiber-optic cables of varying lengths to the beam splitter.

However, optical chips, in which all of the optical components are etched into a silicon substrate, have been developed in recent years, making it much simpler to control the trajectories of photons.Sanders believes that the most significant issue is producing individual photons at intervals that are sufficiently predictable to synchronize their arrival at the beam splitters.Sanders asserts, “People have been working on it for a decade, making great things.

“However, obtaining a train of single photons remains difficult.Rudolph concurs.Right now, the hard thing is getting an adequate number of single photons into the chip,” he says.”My hope is that within a few years, we’ll manage to build the experiment that crosses the boundary of what we can practically do with classical computers,” he adds.