IBM has been offering quantum computing as a cloud service since last year when it came out with a 5 qubit version of the advanced computers. Today, the company announced that it’s releasing 20-qubit quantum computers, quite a leap in just 18 months. A qubit is a single unit of quantum information.

The company also announced that IBM researchers had successfully built a 50 qubit prototype, which is the next milestone for quantum computing, but it’s unclear when we will see this commercially available.

While the earliest versions of IBM’s quantum computers were offered for free to build a community of users, and help educate people on programming and using these machines, today’s announcement is the first commercial offering. It will be available by the end of the year.

Quantum computing is a difficult area of technology to understand. Instead of being built on machines interpreting zeroes and ones in on/off states, quantum computers can live in multiple states. This creates all kinds of new programming possibilities and requires new software and systems to build programs that can work with this way of computing.

Dario Gil, IBM Research VP of AI and IBM Q, says the increased number qubits is only part of the story. The more Qubits you deal with, the more complex the qubit interactions become because they interact with one another in a process called entanglement. If you have more qubits, but there is a high error rate as they interact, then they might not be any more powerful than 5 qubit machine with a lower error rate. He says that IBM researchers have managed to achieve the higher qubit number with low error rates, making them highly useful to researchers. “We have more qubits and less errors, which is combined to solve more problems,” Gil said.

The other issue that comes into play when dealing with quantum states is that they tend to exist for a short period of time in a process known as coherence. It basically means that you only have a brief window of time before the qubits revert to a classical computing state of zeroes and ones. To give you a sense of how this coherence has been progressing, it was just a few nanoseconds when researchers started looking at this in the late 90s. Even as recently as last year, they were able to achieve coherence times of 47 and 50 microseconds for the 5 qubit machines. Today’s quantum machines are in the 90 microsecond range. While that doesn’t sound like much, it’s actually a huge leap forward.

All of these variables make it difficult for a programmer to build a quantum algorithm that can achieve something useful without errors and before it reverts to a classical state, but that doesn’t take away from just how far researchers have come in recent years, and how big today’s announcement is in the quantum computing world.

The ultimate goal of quantum computing is a fault tolerant universal system that automatically fixes errors and has unlimited coherence. “The holy grail is fault-tolerant universal quantum computing. Today, we are creating approximate universal, meaning it can perform arbitrary operations and programs, but it’s approximating so that I have to live with errors and a [limited] window of time to perform the operations,” Gil explained.

He sees this is an incremental process and today’s announcement is a step along the path, but he believes that even what they can do today is quite powerful. With today’s release and the improvements that IBM made to the QISKit, a software development kit (SDK) to help companies understand how to program quantum computers, they can continue to advance the technology. It’s not going to happen overnight, but companies, governments, universities and interested parties are undertaking research to see how this can work in practical application. (And of course, IBM isn’t the only company working on this problem.)

IBM sees applications for quantum computing in areas like medicine, drug discovery and materials science as this technology advances and becomes better understood. It is also trying to anticipate possible negative consequences of an advanced technology such as the ability to eventually be able to break encryption. Gil says they are working with standards bodies to try and develop post-quantum computing encryption algorithms, and while they are a long way from achieving that, they certainly seem to understand the magnitude of the issues and are trying to mitigate them.