Efforts towards realising a practical quantum computer have been given a huge boost after a team of researchers made successful advances in qubit miniaturisation.

Qubits or quantum bits are the basic building blocks behind quantum computing and hold the capacity to process enormous computational tasks in real-time. However, working out how to miniaturise the technology remains a huge obstacle to quantum computer development.

One approach to the challenge involves trapped ions, but this requires large and complicated hardware components. Now, researchers at MIT are developing a prototype chip which is able to trap ions in an electric field and control them using targeted laser technology.

‘If you look at the traditional assembly, it’s a barrel that has a vacuum inside it, and inside that is this cage that’s trapping the ions. Then there’s basically an entire laboratory of external optics that are guiding the laser beams to the assembly of ions,’ said MIT professor of electrical engineering, Rajeev Ram.

‘Our vision is to take that external laboratory and miniaturise much of it onto a chip,’ he explained.

The new chip contains embedded electrodes in its surface which can hold a large number of ions. A set of on-board optical components allow laser beams to target individual ions.

‘Trapped-ion qubits are well-known for being able to achieve record-breaking coherence times and very precise operations on small numbers of qubits. Arguably, the most important area in which progress needs to be made is technologies which will enable the systems to be scaled up to larger numbers of qubits. This is exactly the need being addressed so impressively by this research,’ said Oxford University physics professor David Lucas.

‘As far as I know, this is the first serious attempt to integrate optical waveguides in the same chip as an ion trap, which is a very significant step forward on the path to scaling up ion-trap quantum information processors (QIP) to the sort of size which will ultimately contain the number of qubits necessary for doing useful QIP,’ Lucas added.

Concerned with the advent of quantum computing, last month Google promised to safeguard its products from potential decryption attacks. ‘While they will, no doubt, be of huge benefit in some areas of study, some of the problems that they [quantum computers] are effective at solving are the ones that we use to secure digital communications,’ explained Google software engineer Matt Braithwaite.

Braithwaite suggested that if large quantum computers are built then they could be programmed to break the asymmetric cryptographic primitives, currently used in TLS, the security protocol behind HTTPS.