The proponents of quantum computing (see Video below) claim that calculations done on a quantum computer actually take place in parallel universes. That’s right … there doesn’t seem to be enough room in our own universe, so they are forced to use other … less constrained … universes. The wizard wants to know if this is true. And as a corollary question, NAA asks the question “Is quantum computing proof that parallel universes exist?” I mean how do we know that quantum computing doesn’t actually take place in the men’s room of the MIT physics department or even in the Gender Studies department at Sarah Lawrence for that matter? OK this last one is probably a marginal idea … BUT how do we know for sure where the calculations take place? Inquiring minds want to know.
A BRIEF OVERVIEW OF REGULAR COMPUTERS
A “normal” computer uses binary or simple ON/OFF gates to direct calculations and to store information. It is a straightforward process and could even be done mechanically. One bit of information is a single on/off position. A byte is 8 bits and with 8 bits, you can create a table to represent every letter (lower and upper case) as well as all numbers and special characters in our language. Logic gates allow the bits and bytes to be manipulated and calculations to be made. All the calculations take place in this universe (or at least no one is making a claim to the contrary.)
A BRIEF REFRESHER ON QUANTUM COMPUTING
Quantum Computing does not use bits and bytes, it uses qubits. A qubit is a way of storing information in a quantum computer using probabilities which involve the properties of superposition and entanglement. Superposition means that a state of say an electron (which can be spin up or spin down) can be in two states at the same time, So instead of it being a one or a zero (as with a bit) it can be both a one and a zero (until measured.) Entanglement allows two particles to move together even at great distances. It is what freaked our Einstein when he considered quantum mechanics. He called entanglement “spooky action at a distance.”
With 500 qubits, you could do 2^500 calculations in a single step. And so we have come to the crux (or perhaps the horcrux) of the matter. For you see 2^500 is greater than the number of atoms in the known universe. (I note that visible matter or atoms in the universe is only a tiny portion of the universe given that there is vastly more dark matter and energy than there is “regular matter and energy” but this just changes the scope a bit.)
Thus the argument goes … there aren’t enough atoms in this universe to express what a quantum computer can do with ease, so the calculations must be taking place “somewhere else.” Fair enough. If a normal computer could never make the calculation no matter how big, is something really special happening with a QC?
For more on superposition and entanglement, here is a link that you might find helpful:
DAVID DEUTCH AND THE BEGINNING OF THE QC / MULTIVERSE ARGUMENT
David Deutch was the inventor of the quantum computer and has been one of the fiercest proponents of the theory of the multiverse. His book The Fabric of Reality has been the classic on this subject and to his credit he makes many of his arguments in terms that a layman could understand. In Chapter Two, he talks about the slit experiment where light can be shown to be both a wave and a particle. It is here where we first encounter the “add a slit” paradox. He describes the emergence of an interference pattern of light and dark bands when a laser beam is aimed at an opaque object with two parallel slits. Then he describes how the pattern changes when he adds a second pair of slits to the object, interwoven with the existing pair. It changes the pattern so that the bands of light on the projection screen are twice as far apart as in the previous pattern. So, contrary to what one might expect, opening two extra slits so that more light passes through the object makes some parts of the screen go dark which were previously lit. Deutch concludes that what we can see initially is the universe we know, but that careful control of the experiment introduces shadows that are “not from around here.” The arguments are complex, but well reasoned. Get the book if you want a more thorough understanding.
The key here is that the inventor of the quantum computer is also the biggest proponent of the theory of the multiverse. This is how the connection started.
Keep in mind that the people who gave us the multiverse also gave us Schrödinger’s cat … a cat that was both alive and dead (an idea I believe that he got from observing the U.S. Senate.)
For arguments for the multiverse watch this
For arguments against the multiverse watch this
IS THE “EXCEEDS THE NUMBER OF ATOMS IN THE UNIVERSE” ARGUMENT DISPOSITIVE?
The simple answer is NO. Just because there are a limited number of atoms does not mean that each one can not do multiple calculations. In the time it takes for a Quantum Computer to make a probabilistic prediction about an answer, a standard computer can do many calculations. Thus, just because a single QC register can contain 500 cubits and thus express values that exceed the total atoms in the universe (10^80), it says nothing about the existence of parallel universes. The wizard submits that experiments to prove the existence of parallel universes could be designed BUT the mere existence of a quantum computer does NOT prove that such universes exist.
Also remember we are dealing with probability storage and processing of information. Actual yes / no answers are not the purview of QC’s. Also, there is a rule that a qubit register cannot be copied (remember measuring changes THE state of the information.) Thus the issue of what is really stored where and how much information is stored is highly subjective. For these and other reasons, the Wizard does not believe that parallel universes have been scientifically demonstrated (nor disproven.)
So, is it more likely that calculations on a Quantum Computer take place in parallel universes rather than in the Sara Lawrence Genders Studies Department? Both the Wizard and the QC say “probably YES.”
Is it more likely that calculations on a QC take place in parallel universes rather than just our own universe? Uh Oh … the Wizard says NO … the Quantum Computer says YES.
“BAD COMPUTER … BAD. I am going to rub your nose in the Schrödinger’s cat liter box (if it’s in existence at the time.) And then I am going to lock you in a Heisenberg trap … which is really unpleasant … some of the time.”
Wait … this isn’t working
… or is it?