Every so often, I encounter computing problems that result in what is called a “combinatorial explosion.”

This happens when there are so many states or conditions to evaluate, finding the answer to a highly complex problem using traditional computing would take so long that I must either restructure the problem mathematically and/or scientifically or find different architectures on which to run the problem. These situations crop up for SAIC's customers in various fields like aeronautics, economics, finance, and healthcare.

While these challenges are certainly frustrating to deal with, they are not impossible to overcome, thanks to the sciences of quantum computing and quantum networking. Traditional computing is constrained by binary, or strings of ones and zeroes. Quantum computing, however, uses what we call quantum bits, or qubits, to create an infinite combination of states, including zero and one simultaneously.

Quantum computing enables computation of large sets of probability data -- think clinical studies or finance data -- larger than what traditional computing can handle. Creating infinite possible outcomes in solving a complex problem sounds impossible, but this is known as “superposition” and is one of the phenomena used to perform quantum computing.

Compare superposition to the classic thought experiment of Schrodinger’s cat. Physicist Erwin Schrodinger proposed that a hypothetical cat placed inside of a box containing radioactive material and poison may be considered both alive and dead while the box is closed. While in the box, the cat is in two states, similar to how qubits under superposition can be both zero and one simultaneously.

Quantum networking relies on entanglement, which is the relationship between two physically separated quantum particles that act in perfect unison. When one quantum particle changes, the state of the other one is simultaneously altered. Albert Einstein called this “spooky action at a distance.” Entanglement is the means of transferring data in the form of qubits between physically separated quantum processors.

Through quantum computing and networking, combinatorial complexity is overcome because myriad states can be scrutinized simultaneously through superposition.

Quantum advantages and challenges

At first glance, you could say quantum computing has an obvious advantage over traditional computing because it can handle greater issues. But it’s not that easy.

A quantum computer needs about 72 qubits for it to be superior to a classical computer, and frankly, there aren’t very many quantum computers that powerful. IBM’s most powerful quantum computer has 65 qubits. Google’s most powerful quantum computer has 53 qubits. No quantum computer has claimed “quantum supremacy,” meaning it can’t do anything better than a classical computer.

So, the question arises as to whether quantum computing is practical yet. The field is definitely in its infancy and requires as much physics as it does computer science.