Diamond laser taps into spooky quantum world for true randomization

Randomization may seem simple, but there’s basically no such thing in classical physics – pretty much everything could be theoretically predicted if you had enough information. For true randomization you need to turn to the spooky world of quantum physics, and now scientists have done just that, creating secure encryption keys based on the genuine randomness of quantum vibrations of diamond.

For most everyday uses, our imperfect randomization methods work just fine. Coin flips, dice rolls and software random number generators do the job for gaming, gambling, and computer algorithms, but technically speaking they aren’t truly random – they only appear to be because we as observers don’t have all the information.

So, for example, it would be possible to predict a dice roll result if you knew the exact path the dice would take as they bounced and rolled across the table, as well as the amount of force behind them, the weight of the dice, the air pressure, etc. Of course, there isn’t much danger of a punter at the craps table knowing all this information and bankrupting the house, but in the high-stakes world of communications encryption, pseudo-randomization is a risk.

True randomization isn’t impossible though. It can be found in the realm of quantum physics, since information about an event literally doesn’t exist until the event takes place. Phenomena like the nuclear decay of atoms are fundamentally random and can’t be predicted, so scientists are beginning to use the timings of these events to create more genuine randomness in systems.

For the new study, scientists at Macquarie University developed a new way to tap into this quantum randomness more directly. The team’s new diamond laser system produces pulses of light that have genuinely random polarization states, thanks to the quantum vibrations of the carbon atoms in the diamond lattice.

Random polarizations of light pulses are already in use, but normally the quantum randomness is first taken from another source, such as a radioactive decay event, then mapped onto the laser polarization. The new device performs that function natively, simplifying the system. Better yet, it can also work at room temperature, unlike other materials for this kind of job that need to be cooled to cryogenic temperatures.

“This is an entirely new tool for producing quantum randomness,” says Doug Little, lead researcher on the study. “We are hoping this type of device will provide end-users in fields such as encryption and quantum simulation with a new option for simplifying and enhancing their technology.”

The research was published in the journal Optics Express.

Source: Macquarie University