Quantum Computers: A Primer (sort of)

Stephen DeAngelis

August 20, 2014

“Quantum technologies,” writes Pete Shadbolt, “exploit the paradoxical and unfamiliar behaviour of tiny lumps of light and matter, including single atoms, electrons and photons. Using these ‘quanta’ as building blocks, we can construct machines which exist in quantum ‘superposition’ states. These states are so exotic and unfamiliar that they cannot be adequately described using simple language – we must resort to a mathematical description.” [“Quantum tech disappoints, but only because we don’t get it,” Phys.org, 16 July 2014] I think Shadbolt’s headline says it all, “We don’t get it.” Quantum computing is notoriously difficult to explain and comprehend. Yet the subject holds such promise that the very fate of mankind could rest in hands of those who manage to conquer the subject. Shadbolt explains:

“Machines based on these technologies are expected to dramatically outperform their classical counterparts in a variety of important tasks, including secure communication, computer simulation of atoms and molecules, precision measurement, code-breaking and quantitative analysis of ‘big data’. … The promise of exotic and powerful new machines, coupled with the air of mystery often associated with quantum theory, has made quantum technologies a topic of constant discussion in the mainstream press. … While strong public and private investment suggest practical quantum technologies are closer to market than ever before, [a study by Sciencewise] notes a certain amount of pessimism in recent coverage. The authors identify a sense of frustration, in newspaper reports and online reader comments, over the idea that quantum computing has been ‘on the horizon’ for more than a decade – and might stay there forever.”

To read about how the promise of quantum computing has remained just beyond the grasp of science, read my article entitled “Quantum Future: Just Beyond Our Grasp.” Although there might be a sense of frustration over the slow pace of development, constant progress towards creating a functional quantum computer is being made. An article published by Phys.org is optimistic that quantum computers will be created and that they “will be much more powerful than those we have today.” [“The road to quantum computing,” 15 May 2014] “But,” the article admits, “they do not exist yet.” What do exist are scientists studying quantum computers. The article then asks a good question, “So, what do quantum computer scientists study?” The simple answer is that they study quantum theory, material science, and mathematics. You might be surprised to learn that some mathematicians are creating “algorithms to be used if and when quantum computers will be built.” One such individual is Andris Ambainis, professor of computing at the University of Latvia. He was interviewed for the article. He explained his take on what scientists are doing in the area of quantum computing.

“First, we try to answer the question: what can be computed with quantum computers, once we build them? Also, we have to foresee limitations of these new devices. For example, to identify computational problems that would be difficult to solve even for a quantum computer. Then we study applications of quantum computing in communication, to learn how to accomplish communication tasks more efficiently. Finally, we study its applications to other areas, such as non-quantum computer science or quantum physics.”

Ambainis believes that a functional quantum computer will be built within the next two decades. He went on to explain what such a computer would be able to do.

“We would be able to search through a large amount of data, regardless of their nature. Secondly, we could model physics effectively. For the time being, if we want to model quantum physical systems, conventional computers are quite poor. Quantum computers would be much better. And this, in turn, would have many applications, for example, in material science or in chemistry. Since researchers find new materials and chemicals by modelling them on computers.”

Barb Darrow (@gigabarb) exclaims, “If you’re still perplexed by what, exactly, quantum computing is, you’re not alone.” [“Still confused about quantum computing? This may help,” Gigaom, 24 July 2014] Videos can help explain quantum computing. Concerning the following video, Mike James reports, “This animation … might give you some idea as to why quantum computers are more powerful – or potentially more powerful – than a classical computer.” [“Quantum Computers Animated,” I Programmer, 25 August 2013] As terrific as the animation is, James warns that you are still likely “to be mystified. Quantum computers are difficult to understand because they rely on the mathematics of quantum mechanics and most people don’t understand the math.”

 

 

Lev Grossman, writes, “Taking advantage of bizarre effects like quantum superposition and quantum entanglement, quantum computers have the potential to unlock massive amounts of processing power, and to solve problems that would take conventional computers literally centuries.” [“Quantum Computing: A Primer,” Time, 7 February 2014] Earlier this year, he included the video shown below in his article to help explain the weird world of quantum computing.

 

 

I hope you were able to gather something new from each of those videos. Wrapping one’s mind around the subject is not easy, but, you have to admit, the videos help — sort of.