# Quantum computer secrets

In May 2013, NASA and Google splashed out on a D-wave 2 (pictured below), the first commercially available quantum computer. We spoke to Dr Rupak Biswas, deputy director of the Exploration Technology Directorate at the Ames Research Center, to find out its potential.

**What kind of problems is NASA investigating with the D-wave computer?**

NASA has a bunch of difficult optimisation or search problems. Say you want to plan a certain navigation route for the Mars rover; there are many ways of charting that route, but you want to minimise the resources you use. This is a hard optimisation problem because there are many ways of doing it and many variables at play.

**How can a quantum computer solve this problem more effectively?**

On a classical computer, you make assumptions and reduce the problem’s complexity so you can get a solution in a reasonable amount of time, but there’s no guarantee it’s the optimal solution. With quantum computing you can look at all possible solutions simultaneously.

**How does the basic functioning of a quantum computer differ from a conventional one?**

In a classical computer you have millions of bits, each of which is a 0 or a 1. In a quantum computer you have qubits, which are 0, 1 and all numbers between 0 and 1 at once.

**How does the D-wave solve a problem?**

The trick to solving a problem on a quantum computer is solving the same problem many times. Each time you get a different answer with a probability, and the one with the highest probability is the best answer.

**What is next for quantum computing?**

The D-wave machine is just one way of making a quantum computer – a whole community will grow around quantum computing, which will take time. But now we’re beyond the conceptual stage, scientists can play around with quantum computers and think about how these machines could be used [most] efficiently in the future.