Quantum computing - D-Wave Computer - Part 1

The D-Wave computer.

This is one of a few articles I want to write on quantum computing, this particular article is intended only as an introduction. I will cover some technical details, but only in brief. I am more interested, and concerned with what quantum computing means to us and more importantly how it will affect us all.

I don't entirely understand the physics behind the D-Wave, but I have learnt a few things about the system, and the more I have learnt, the more interesting it has become.

The D-Wave system, is one of many quantum computer systems currently under development. The D-Wave system, is the first commercially available quantum computing system, last check they retailed at about $15 - 20 Million a piece.

Key players in the D-Wave compay are:

Vern Brownell, CEO
Geordie Rose, Founder
Eric Ladizinsky, CS
V. Paul Lee, Chair

There is so much to discuss that I'm not really sure where to start, and for what I want to cover, the beginning is probably the wrong place. So I'll describe here a very brief outline of what the D-Wave computer is, and the science on which it is based, before I discuss anything else. Please don't quote me here, and please feel free to correct me if you know better, as I'm only just about grasping all this myself.

The D-Wave system is based on a Quantum annealing processor, its power is measured in Qubits or Q-bits. A Qubit is a unit of quantum information, analogous to a single conventional switch of a silicon based processor. In a conventional processor, the switching is carried out by an FET or MOSFET switching transistor, whereas in a quantum processor the 'switching' is carried out by josephson junctions. A single josephson junction is equal to one qubit in function - therefore a 128 qubit quantum annealing processor would utilise 128 josephson junctions, a 256 qubit, 256 junctions and so on. Getting a josephson junction to function is no easy thing, and to describe that function is not a simple matter.

Drawing a parallel between an fet or mosfet device and a josephson junction is really not a good analogy, as its function is based on an entirely different physics to that of an fet device, however, the work it does is in some ways similar, or rather the results we glean from a josephson junction are measured in a similar way. In an fet switching device, a gate can either be at zero volts representing zero, or it can be at + volts representing 1. If an fet gate is positive going we can assume a current is flowing in one direction, and if the gate is off we can assume there is no current flowing through that junction.

A josephson junction or quantum annealing gate has a slightly different function.

Josephson junctions are an integral feature of superconducting quantum computers, represented as qubits or flux qubit or other configurations where the phase and charge act as the variable.

The Josephson effect is based on a phenomenon known as super-current, which is a current that flows indefinitely without a voltage applied across a Josephson junction. This is achieved using super cooled, superconducting materials. In this one statement we begin to see already that a josephson junction is not a normal electronic device, and requires special handling if we are to make it in any way useful. If we look at the physical D-Wave computer casing, we see a very large cabinet, most of which is apparatus for cooling the very much smaller device inhabiting the case, which is the quantum processor itself.

From here on, it just becomes ever more complex for any normal description. However, to demonstrate one particular property that indicates further we are dealing with something 'other' when it comes to physics. One particular property that might highlight this better, is the way in which a quantum annealing junction functions against the physical rules we are familiar with. One aspect is that of current flow, where a current can be caused to flow in one direction, it may also flow simultaneously in the opposite direction, i.e, 180 degrees out of phase. In any normal non quantum device, this is simply not possible, and goes against our 'normal' rules of physics, whereby a current may only flow in one direction or another. For those of you familiar with electronic and electrical devices, you will understand how impossible this seems. It is only possible of course, if we enter into the realm of quantum physics.

To anyone not familiar with electronics or electrical devices, a good way to imagine this effect, is with an electric motor such as in an electric bicycle. If you cause a current to flow in an electric motor driving a bicycle, then it will rotate in one direction only, either forward, or reverse, in accordance with the current direction, and if you change the direction of current flow, it will rotate in the opposite direction - whereas if this were a quantum bicycle, we would be able to cause a current to flow in both directions simultaneously, the bicycle would of course move neither forward or backward, however, in a quantum processor, this third state, can do useful work for us, and our bicycle would assume a third state of function, that we have yet to become familiar with.

Contrary to popular belief, a quantum computer is no faster than any conventional computer, in fact the present released D-Wave computers, are very slow by comparison, and can be outgunned quite easily by a silicon based fet CPU computer. Indeed it is not speed of process that is important with respect the quantum processor, but rather what it does and how it does that. The quantum annealing processor functions in a different physical realm to a silicon fet device. I'm not going to describe further how that occurs, as I am ill equipped to do so, but instead we'll leave it there. What I am more interested in is the company that produces these machines, and the people involved, and more importantly, their objectives. For those who want to delve further there's plenty of information out there describing this functionality.

I must reiterate, this is not intended to be a technical article, and there are many blogs already on this subject, and it is not my intention to reinforce any of those views. I have a particular take on the world of quantum computing, and it has less to do with what they might do for us, and more to do with what they might do despite us.

So this is my introduction to this series of blogs, the next in the series we will take a look at the objectives of the D-Wave company, through the words of founder Geordie Rose, and D-Waves chief scientist Eric Ladizinsky.

If u have anything to add so far, or any view of this science that might be of interest, please let me know in the comments, and I'll try to cover it best I can.

Thanks for reading.