Google's much-doubted quantum computer may just be the real deal

When Google announced last month that it would be making use of a quantum computer machine, quite a few were skeptical about whether this would actually work.


When Google announced last month that it would be making use of a quantum computer machine, quite a few were skeptical about whether this would actually work. The company said the computer will help advance machine learning, which is used to create systems that can learn in much the same way as humans do, according to a report by Wired.

In a Google post, Hartmut Neven, a Google Director of Engineering said, “We believe quantum computing may help solve some of the most challenging computer science problems, particularly in machine learning. Machine learning is all about building better models of the world to make more accurate predictions.” While the world’s biggest search engine is clear about what it is using, many researchers and scientists around the world are not. The question that everyone is grappling with is, can quantum computers really exist? According to D-Wave, the company that built the machine, the invention really is the world’s first quantum computer, which is supposed to be the future of mathematical calculations as we know it.

What is a quantum computer, you might ask? The concept first surfaced in 1985 and was put forward by British physicist David Deutsch. Essentially, a quantum computer is a machine that works according to the mind-bending principles of quantum mechanics, which is the physics behind very small things like electrons and photons. Your everyday computers use a transistor that stores a single "bit” of information. So, if the transistor is “on,” it will hold “1” bit of information. And if it is “off,” it will hold “0.” It is a bit different with a quantum computer, though, because information is held in a system that can exist in two states at the same time, courtesy a system called the superposition principle of quantum mechanics.

An inside look at D-Wave's 512 quibit machine, which Google is now using. (Image credit: BBC)

An inside look at D-Wave's 512 quibit machine, which Google is now using. (Image credit: BBC)

 

 

In quantum computers, this “quibit” can store a “0″ and “1″ at the same time. Now, if developers can build two quibits, the computer can hold four values at once, with combinations like 00, 01, 10, and 11 being the possibilities. By that simple logic, as you attach more and more quibits, the computer made will be exponentially more powerful than any other computer available in the world now.

 

But there is a catch. Building a single quibit is quite a task. That is because, whenever someone tries to read information from a quantum system, the quibit breaks down. Basically, the information becomes an ordinary bit which is only able to hold a single value. Thus, the quantum computer becomes an ordinary one.

 

While D-Wave has said that it has worked around this problem, there are skeptics. Fresh evidence does seem to support what the company has to say. Researchers at the University of Southern California have published a paper today that comes that much closer to showing that the D-Wave machine is indeed a quantum computer. The paper, titled Experimental Signature of Programmable Quantum Annealing states that the machine is not using a computing model known as “simulated annealing”, which obeys the laws of classical physics i.e. the physics of everyday life. Daniel Lidar, a professor of electrical engineering, chemistry and physics,  who leads the USC researchers, said “Our research rules out one type of classical model that has been argued as a proper description of the D-Wave machine. A lot of people thought that when D-Wave came on the market their machine was just doing that (simulated annealing), but we ruled that out.”

 
The paper, which was seen in the academic journal Nature Communications, clearly says that quantum annealing is a computing model that operates in the quantum realm. And according to their research, the team shows clear links between quantum annealing and the way the D-Wave system operates. The company's solution seems elegant. The machine, which Google is using, sports 512 superconducting circuits, each of which comes with a tiny loop of flowing current. The circuits are cooled to almost absolute zero so as to enter a quantum state which sees the current flowing clockwise and counter-clockwise at the same time.

 

Thus, when a researcher gives the machine a task, it makes use of a set of algorithms which spreads this calculation across these quibits to work on it simultaneously. The company states that this involves determining the probability that a given set of circuits will join together in a particular pattern while the temperature inside the system is raised.

 

While scientists are skeptical about this machine, the USC paper helps to shine a little more light on the subject. However, the paper does not talk about the system that the machine actually uses. While researchers have proven that the machine does not use simulated annealing, which is essentially a means of searching for a mathematical solution, Lidar clearly states that his research does not prove that D-Wave uses quantum annealing, although the system appears to use it.

 

Be that as it may, with Google’s approval, the machine, which may or may not be a quantum computer, is definitely getting the work done. And semantics aside, that is what really matters, at least to the search engine.  


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