Pick a card, any card. Like a devious magician, the Universe already knows your selection as the laws of physics guide everything from your neurological wiring to the contractions of your hand's muscles.
But, if asked to pick a particle from an empty patch of space, you might have a chance of fooling the Universe. Because there you'll find a form of randomness like no other, one engineers have learned to tap into in their search for the truly unpredictable.
Thanks to innovations developed by researchers from institutions in Belgium, Denmark, and Italy, we can run this search in record time, plucking 100 gigabits worth of data out of literal nothingness every second.
What you typically think of as randomness is, at best, a reflection of your ignorance. No offense. A friend who 'randomly' pops by for a coffee knows with 100 percent confidence that they're going to your house. It's only random because you don't know it.
Likewise, the flip of a coin, the roll of a die, the arrival of a storm, or the impact of an asteroid isn't truly random events either. Each is governed by a complex web of knock-on effects which, in theory, could be individually predicted given enough knowledge.
The same can't be said for quantum systems. Zoom right up close to a particle, and you might learn its position, but its energy is a spectrum of possibility. Know its energy with absolute precision, and its location will become an unknowable property smeared across space.
Ditch the particle, and space itself will follow the same quantum rules. Zoom in on an empty patch of nothingness, the energy present will include possibilities that, in theory, would generate particles.
These 'virtual' particles aren't mere concoctions of our imagination, either. They exist, in a quantum kind of way, emerging and annihilating in a flicker that we refer to as quantum foam.
Long known to affect a wide range of physical phenomena from the way lasers are generated to how chemical bonds scatter light, it's not difficult to tap into quantum foam in the name of random data generation. What is an ongoing challenge is finding a reliable method that doesn't require a whole lot of equipment that can slow the process and make it harder to employ out in the field.
The researchers behind this latest advance show how a device called an integrated balanced homodyne detector delivers results several times faster than other novel approaches, without a lot of added baggage.
Homodyne detection measures features of a quantum state's electric field, which is handy for continuously keeping track of the snap, crackle, and pop of virtual particles.
Unfortunately, quantum states have a frustrating habit of entangling with the less-quantum features of their environment, making them less random than your neighbor popping over to borrow your lawnmower, yet again.
To deal with this environmental 'noise' influencing the readings in their homodyne detector, the team integrated technology that could identify sources of potential interference and take them into account, improving the system's sensitivity to actual random fluctuations.
Shrunk down, the end result is a chip-scale platform capable of reliably pumping out random numbers for all your encryption needs.
As computing grows in power and our need to lock away secrets from prying eyes becomes ever more pressing, reliable means of ensuring data can be transferred safely becomes ever more important.
That means large strings of code that no computer can come close to guessing.
Of course, random numbers are useful in a whole variety of fields, from ensuring your study samples are unbiased to determining whether your level five elf mage in Dungeons and Dragons can hit the giant with a magic missile.
They could even make for the ultimate magic trick.
This research was published in PRX Quantum.