Tag Archives: holographic principle

Measuring the Quantum Jitter

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.

In a presentation given in Chicago on Monday at the International Conference on Particle Physics and Cosmology, Hogan said that the initial results show the Holometer is capable of measuring quantum fluctuations in space-time, if they are there.

“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.

Are You Real, Or Are You a Hologram?

The principle of a holographic universe, not to be confused with the Holographic Universe, an album by swedish death metal rock band Scar Symmetry, continues to hold serious sway among a not insignificant group of even more serious cosmologists.

Originally proposed by noted physicists Gerard ‘t Hooft, and Leonard Susskind in the mid-1990s, the holographic theory of the universe suggests that our entire universe can described as a informational 3-D projection painted in two dimensions on a cosmological boundary. This is analogous to the flat hologram printed on a credit card creating the illusion of a 3-D object.

While current mathematical theory and experimental verification is lagging, the theory has garnered much interest and forward momentum — so this area warrants a brief status check, courtesy of the New Scientist.

[div class=attrib]From the New Scientist:[end-div]

TAKE a look around you. The walls, the chair you’re sitting in, your own body – they all seem real and solid. Yet there is a possibility that everything we see in the universe – including you and me – may be nothing more than a hologram.

It sounds preposterous, yet there is already some evidence that it may be true, and we could know for sure within a couple of years. If it does turn out to be the case, it would turn our common-sense conception of reality inside out.

The idea has a long history, stemming from an apparent paradox posed by Stephen Hawking’s work in the 1970s. He discovered that black holes slowly radiate their mass away. This Hawking radiation appears to carry no information, however, raising the question of what happens to the information that described the original star once the black hole evaporates. It is a cornerstone of physics that information cannot be destroyed.

In 1972 Jacob Bekenstein at the Hebrew University of Jerusalem, Israel, showed that the information content of a black hole is proportional to the two-dimensional surface area of its event horizon – the point-of-no-return for in-falling light or matter. Later, string theorists managed to show how the original star’s information could be encoded in tiny lumps and bumps on the event horizon, which would then imprint it on the Hawking radiation departing the black hole.

This solved the paradox, but theoretical physicists Leonard Susskind and Gerard ‘t Hooft decided to take the idea a step further: if a three-dimensional star could be encoded on a black hole’s 2D event horizon, maybe the same could be true of the whole universe. The universe does, after all, have a horizon 42 billion light years away, beyond which point light would not have had time to reach us since the big bang. Susskind and ‘t Hooft suggested that this 2D “surface” may encode the entire 3D universe that we experience – much like the 3D hologram that is projected from your credit card.

[div class=attrib]More from theSource here.[end-div]

[div class=attrib]Image courtesy of Computerarts.[end-div]