Some physicists are determined to find out if we are mere holograms. Perhaps not quite like the dystopian but romanticized version fictionalized in The Matrix, but still a fascinating idea nonetheless. Armed with a very precise measuring tool, known as a Holometer or more precisely twin correlated Michelson holographic interferometers, researchers aim to find the scale at which the universe becomes jittery. In turn this will give a better picture of the fundamental units of space-time, well beyond the the elementary particles themselves, and somewhat closer to the Planck Length.
From the New Scientist:
The search for the fundamental units of space and time has officially begun. Physicists at the Fermi National Accelerator Laboratory near Chicago, Illinois, announced this week that the Holometer, a device designed to test whether we live in a giant hologram, has started taking data.
The experiment is testing the idea that the universe is actually made up of tiny “bits”, in a similar way to how a newspaper photo is actually made up of dots. These fundamental units of space and time would be unbelievably tiny: a hundred billion billion times smaller than a proton. And like the well-knownquantum behaviour of matter and energy, these bits of space-time would behave more like waves than particles.
“The theory is that space is made of waves instead of points, that everything is a little jittery, and never sits still,” says Craig Hogan at the University of Chicago, who dreamed up the experiment.
The Holometer is designed to measure this “jitter”. The surprisingly simple device is operated from a shed in a field near Chicago, and consists of two powerful laser beams that are directed through tubes 40 metres long. The lasers precisely measure the positions of mirrors along their paths at two points in time.
If space-time is smooth and shows no quantum behaviour, then the mirrors should remain perfectly still. But if both lasers measure an identical, small difference in the mirrors’ position over time, that could mean the mirrors are being jiggled about by fluctuations in the fabric of space itself.
So what of the idea that the universe is a hologram? This stems from the notion that information cannot be destroyed, so for example the 2D event horizon of a black hole “records” everything that falls into it. If this is the case, then the boundary of the universe could also form a 2D representation of everything contained within the universe, like a hologram storing a 3D image in 2D .
Hogan cautions that the idea that the universe is a hologram is somewhat misleading because it suggests that our experience is some kind of illusion, a projection like a television screen. If the Holometer finds a fundamental unit of space, it won’t mean that our 3D world doesn’t exist. Rather it will change the way we understand its basic makeup. And so far, the machine appears to be working.
“This was kind of an amazing moment,” says Hogan. “It’s just noise right now – we don’t know whether it’s space-time noise – but the machine is operating at that specification.”
Hogan expects that the Holometer will have gathered enough data to put together an answer to the quantum question within a year. If the space-time jitter is there, Hogan says it could underpin entirely new explanations for why the expansion of our universe is accelerating, something traditionally attributed to the little understood phenomenon of dark energy.
Read the entire article here.