We all have a basic understanding of how our regular computers work. From the smallest chip in a fitness wearable up to the fastest supercomputer, our computers are Turing machines that convert data into bits represented by either a 1 or a 0 and then process data linearly through algorithms. An algorithm can be something simple like adding a column of numbers on a spreadsheet or something complex like building a model to predict tomorrow’s weather.
Quantum computing takes advantage of a property found in subatomic particles. Physicists have found that some particles have a property called superposition, meaning that they operate simultaneously in more than one state, such as an electron that is at two different levels. Quantum computing mimics this subatomic world by creating what are called qubits which can exist as both a 1 and a 0 at the same time. This is significant because a single qubit can perform two calculations at once. More importantly, though, qubits working together act exponentially. Two qubits can perform four calculations at once, three can perform eight calculations and a thousand qubits can perform . . . a lot of calculations at the same time.
This is intriguing to computer scientists because there are a number of challenges that need more computing power than can be supplied by even the fastest Turing computers. This would include such things as building a model that will more accurately predict the weather and long-term climate change. Or it might involve building a model that accurately mimics the actions of the human brain in real time.
Quantum computers should also be useful when looking at natural processes that have some quantum mechanical characteristics. This would involve trying to predict complex chemical reactions when designing and testing new drugs, or designing nanoparticle processes that operate at an atomic level.
Quantum computers also should be good at processes that require trying huge numbers of guesses to find a solution when each guess has an equal chance of being correct. An example is cracking a password. A quantum computer can try all of the possible combinations quickly while a normal computer would toil away for hours plugging in one choice after another in a linear fashion.
Quantum computing is in its infancy with major breakthroughs coming only a few years ago. Scientists at Yale created the first qubit-based quantum computing processor in 2009. Since then there have been a few very basic quantum computers built that demonstrate the potential of the technology. For instance, in 2013 Google launched the Quantum Artificial Intelligence Lab, hosted by NASA’s Ames Research Center, using a 512 qubit computer built by D-Wave.
For the most part, the field is still exploring the basic building blocks needed to build larger quantum computers. There is a lot of research looking at the best materials to use to produce reliable quantum chips and the best techniques for both programming and deciphering the results of quantum computing.
There are numerous universities and companies around the world engaged in this basic research. Recently, Google hired John Martinis and his team from the University of California at Santa Barbara. He is considered one of the foremost experts in the field of quantum computing. Martinis is still associated with the UCSB but decided that joining Google gave him the best resources for his research.
The NSA is also working on quantum computers that will be able to crack any codes or encryption. Edward Snowden released documents that show that the agency has two different initiatives going to produce the ultimate code-breaking machine.
And there are others in the field. IBM, Microsoft, and Facebook all are doing computer research that includes quantum computing techniques. It’s possible that quantum computing is a dead end that won’t produce results that can’t be obtained by very fast Turing computers. But the theory and early prototypes show that there is a huge amount of potential for the new technology.
Quantum computers are unlikely to ever make it into common use and will probably be limited to industry, universities or the government. A quantum computer must be isolated from external influences and will have to operate in a shielded environment. This is due to what is called quantum decoherence, which means that that just ‘looking’ at a quantum component by some external influence can change its state, in the same manner of opening the box determines the state of Schrodinger’s cat. Quantum computing brings quantum physics into the macro world, which is both mystifying and wonderful.