A question on quantum computing and de Broglie's pilot wave theory

Question

I don't know much about quantum computing except what I have read about on wiki and popsci. I have been reading about the de Broglie-Bohm pilot wave theory and how they describe quantum mechanics in terms of discrete particle traveling a pilot wave and it seems produce the same quantum mechanical statistics as the Copenhagen version. some experiments by fluid dynamicists from MIT also seem to support this alternate view.

My question is if this alternate view is the correct view of reality would that effect quantum computing in any way? ie. dealing with discrete particles instead of probabilistic "particles". both theories explain the superposition of waves and both produce the same stats so I would guess not.

Answer 1

For what it's worth (I don't know much about quantum computing): http://arxiv.org/abs/1012.4843 . Abstract: "Much attention has been drawn to quantum computing and the exponential speed-up in computation the technology would be able to provide. Various claims have been made about what aspect of quantum mechanics causes this speed-up. Formulations of quantum computing have traditionally been made in orthodox (Copenhagen) and sometimes many-worlds quantum mechanics. We will aim to understand quantum computing in terms of de Broglie-Bohm Pilot-Wave Theory by considering different simple systems that may function as a basic quantum computer. We will provide a careful discussion of Pilot-Wave Theory and evaluate criticisms of the theory. We will assess claims regarding what causes the exponential speed-up in the light of our analysis and the fact that Pilot-Wave Theory is perfectly able to account for the phenomena involved in quantum computing. "

Answer 2

The only way that a change of interpretation can effect quantum computing is due to the different mathematical representation of the dynamics (which, strictly speaking, is not even part of the interpretation). There may be advantages to the "programming" of quantum computers by going into a pilot-wave representation. Other than that "interpretations" and "ontologies" have no consequences in physics.

Some people feel more comfortable using a different language for the same phenomenon, and that's perfectly valid. In case of programming languages I prefer Python for most of my work, even though I also "talk" C, C++, VBA, VHDL and Verilog (and can pick up the basics of pretty much any other language that I have to adopt for whatever reason). All of these languages are essentially describing the same computational domain. For the context of quantum computing the basic representations of QM (including all of its interpretations) are all low level assembly languages. To the best of my knowledge there is, so far, little progress in defining a formalism that allows non-experts to do quantum computations. That, however, is one of the major theoretical hurdles for quantum computing: how do we let ordinary programmers write software for these systems? After all, programmers of classical computers are not required to be computer architects and to write their own compilers either. If they had to, classical computing would still be in the stone ages of the 1950s.

Answer 3

De Broglie's pilot-wave theory dispenses with the need for the superposition doctrine. (Google "Schrodinger's cat".)

Though this probably wouldn't affect the implementation of quantum computing, removing the obstacle of the superposition doctrine would affect people's mental image of what's happening in a quantum computer.

WITH superposition, the mental image is one of a state that's undetermined until it's read / measured.

WITHOUT superposition, the mental image is more one of a naturally occurring wheel of fortune--or random-number generator--that's cycling at a mind boggling frequency. This frequency would be somewhere near the scale of dividing the speed of light by the diameter of an electron, or around 3e^26 hz. (300,000,000,000,000,000,000,000,000 or three hundred septillion hz.)

The reason that this alternate mental image might not affect implementation is that typical quantum-computing algorithms work the same when applied to simple random-number generators as they do when applied to qubits. Qubits can just generate the random values WAAAY more quickly than typical random-number generators, so computer problems that require random values can especially be HUGELY benefited, performance-wise, by quantum computing.

Answer 4

Different interpretations can sometimes have different predictions. For example, Bell's theorem says that no interpretation of quantum mechanics that is local can quantum mechanics predictions about certain entangled particles. However there many be no differences in predictions between pilot-waves and the standard interpretation. They seem to be mathematically equivalent. I say they 'seem' to be equivalent only because there's some controversy about whether the way they deal with measurement is equivalent. Assuming it is though, they make identical predictions. In that case it can be easier to think in terms of one theory or the other but both would give you the same conclusion.