A look at the holographic principle in a different context
On the last page, we considered the holographic principle and its sister information theory in the context of their relationship to black holes. We noted that the same principles are capable of being elevated to a wider principle applicable to anything in the universe which carries energy, for example, matter and light, and may also be capable of application in our local world where all the action appears to take place in three dimensions, but all the information about us is stored on surfaces that have just two. But how does this happen? A hologram is really a standard two-dimensional image, but light reflected back from the object the light is shining upon gives the impression of an image which is three dimensional.
Imagine an object in a room surrounded by flashes from a camera popping off in the dark. When the light travelling inwards strikes the walls, it defines a surface. It appears as a bubble collapsing at the speed of light. On this two-dimensional surface – a so-called “light sheet” – all the information about you and me and everything else in that room is stored. When the light in the form of a so-called so-called light sheet strikes the walls of the room, it bounces back giving the illusion of a third dimensional reality. The light sheet projects the information contained on its surface into the world creating all that we see and giving rise to the fabric of spacetime itself [1].
In this way, the holographic principle dictates that our three-dimensional world emerges out of information “printed” on two-dimensional surfaces. The surface is where the fundamental physical processes actually happen, and our third dimensional reality is really a holographic projection of these two dimensional physical processes, with the result that there are physical processes taking place on some distant surface that are linked to what I am doing at this very moment[2] - the so-called holographic universe or multiverse described in Chapter 9 of Greene’s Hidden Reality (2011).
Another problem which emerges is that, although physicists mostly agree that the holographic principle is true – that information on nearby surfaces contains all the information about the world – they know not how the information is encoded, how nature processes these zeros and ones, nor how the result of that processing gives rise to the world. Perhaps the universe works like a computer – in the sense that information conjures up what we perceive to be a physical reality – but right now that computer appears as something more like “a big black box”[3]. So is the world we inhabit really something akin to this?
These principles are not east to grasp, and I must say that of all the things which I as a layman find most difficult to fathom in physics and cosmology, the holographic principle would have to take the cake, and that is even after taking into account such things as negative pressure and repulsive gravity, the whole of quantum mechanics (which even its adherents admit no one really understands), string theory with its branes, hidden dimensions and supersymmetry, and M-theory.
Is space analogue or digital?
Following on from there, a Michelson-Morley type experiment is currently (2012) underway investigating the principle that the universe emerges from information, and specifically that imprinted on two-dimensional time sheets: the kind of thing we considered on the last page. The experimenter, Craig Hogan, a physicist at the University of Chicago and director of the Fermilab Particle Astrophysics Centre near Batavia, Illinois, believes that although space may appear to be smooth and infinitely continuous (analogue in other words; not broken up into bits) it is in fact discrete or quantised, emerging out of some deeper system, some fundamentally quantum system that we do not yet fully understand. He hopes that his holometer, designed to test his hypothesis, meets with better success than Michelson and Morley did with their interferometer[4].
On the other hand, not everyone agrees that reality is necessarily atomist, pointillist, digital or quantised, and there are still those who subscribe to the view that the physical world is actually continuous and more analogue than digital. On this view, it is the waves and not the particles that are important. The particles or integers represent not the input of the theory, but the output. Deep down, the theory is not quantum at all and the processes described by the theory mould discreteness from underlying continuity. Niels Bohr may have regarded quantisation (reality in small packets) as the heart and soul of Quantum Mechanics, but Schrödinger brought all this into perspective with his wave equation containing only continuous quantities in 1926.
“Physicists routinely teach that the building blocks of nature are discrete particles such as the electron or quark. That is a lie. The building blocks of our theories are not particles but fields: continuous, fluid like objects spread throughout space. The electric and magnetic fields are familiar examples, but there are also an electron field, a quark field, a Higgs field and several more”. In other words, the objects that we call fundamental particles may not be fundamental after all. They may instead be composed of ripples of continuous fields[5].
[1] Michael Moyer, “Is Space Digital?” Scientific American, February 2012, 20-26 with an accompanying explanatory graphic at 24.
[2] Greene (2011), 258-261; Moyer, op cit.
[3] Moyer, op cit at 25.
[4] “The Unquantum Quantum”, Scientific American, December 2012, 32,35. Hogan's interferometer is described on page 23 of the Moyer article.
[5] David Tong, "The Unquantum Quantum", Scientific American, December 2012, but see www.huffingtonpost.com/victor-stenger/particles-are-for-real_b_2177361.html See also the segment on Quantum Field Theory.
Imagine an object in a room surrounded by flashes from a camera popping off in the dark. When the light travelling inwards strikes the walls, it defines a surface. It appears as a bubble collapsing at the speed of light. On this two-dimensional surface – a so-called “light sheet” – all the information about you and me and everything else in that room is stored. When the light in the form of a so-called so-called light sheet strikes the walls of the room, it bounces back giving the illusion of a third dimensional reality. The light sheet projects the information contained on its surface into the world creating all that we see and giving rise to the fabric of spacetime itself [1].
In this way, the holographic principle dictates that our three-dimensional world emerges out of information “printed” on two-dimensional surfaces. The surface is where the fundamental physical processes actually happen, and our third dimensional reality is really a holographic projection of these two dimensional physical processes, with the result that there are physical processes taking place on some distant surface that are linked to what I am doing at this very moment[2] - the so-called holographic universe or multiverse described in Chapter 9 of Greene’s Hidden Reality (2011).
Another problem which emerges is that, although physicists mostly agree that the holographic principle is true – that information on nearby surfaces contains all the information about the world – they know not how the information is encoded, how nature processes these zeros and ones, nor how the result of that processing gives rise to the world. Perhaps the universe works like a computer – in the sense that information conjures up what we perceive to be a physical reality – but right now that computer appears as something more like “a big black box”[3]. So is the world we inhabit really something akin to this?
These principles are not east to grasp, and I must say that of all the things which I as a layman find most difficult to fathom in physics and cosmology, the holographic principle would have to take the cake, and that is even after taking into account such things as negative pressure and repulsive gravity, the whole of quantum mechanics (which even its adherents admit no one really understands), string theory with its branes, hidden dimensions and supersymmetry, and M-theory.
Is space analogue or digital?
Following on from there, a Michelson-Morley type experiment is currently (2012) underway investigating the principle that the universe emerges from information, and specifically that imprinted on two-dimensional time sheets: the kind of thing we considered on the last page. The experimenter, Craig Hogan, a physicist at the University of Chicago and director of the Fermilab Particle Astrophysics Centre near Batavia, Illinois, believes that although space may appear to be smooth and infinitely continuous (analogue in other words; not broken up into bits) it is in fact discrete or quantised, emerging out of some deeper system, some fundamentally quantum system that we do not yet fully understand. He hopes that his holometer, designed to test his hypothesis, meets with better success than Michelson and Morley did with their interferometer[4].
On the other hand, not everyone agrees that reality is necessarily atomist, pointillist, digital or quantised, and there are still those who subscribe to the view that the physical world is actually continuous and more analogue than digital. On this view, it is the waves and not the particles that are important. The particles or integers represent not the input of the theory, but the output. Deep down, the theory is not quantum at all and the processes described by the theory mould discreteness from underlying continuity. Niels Bohr may have regarded quantisation (reality in small packets) as the heart and soul of Quantum Mechanics, but Schrödinger brought all this into perspective with his wave equation containing only continuous quantities in 1926.
“Physicists routinely teach that the building blocks of nature are discrete particles such as the electron or quark. That is a lie. The building blocks of our theories are not particles but fields: continuous, fluid like objects spread throughout space. The electric and magnetic fields are familiar examples, but there are also an electron field, a quark field, a Higgs field and several more”. In other words, the objects that we call fundamental particles may not be fundamental after all. They may instead be composed of ripples of continuous fields[5].
[1] Michael Moyer, “Is Space Digital?” Scientific American, February 2012, 20-26 with an accompanying explanatory graphic at 24.
[2] Greene (2011), 258-261; Moyer, op cit.
[3] Moyer, op cit at 25.
[4] “The Unquantum Quantum”, Scientific American, December 2012, 32,35. Hogan's interferometer is described on page 23 of the Moyer article.
[5] David Tong, "The Unquantum Quantum", Scientific American, December 2012, but see www.huffingtonpost.com/victor-stenger/particles-are-for-real_b_2177361.html See also the segment on Quantum Field Theory.