# 'Dressed Qubits' With 10X Better Stability Bring Us Closer To Practical Quantum Computers

Australian engineers from the University of New South Wales (UNSW) were able to build a quantum bit that can remain in a stable superposition for ten times longer than was previously possible. As quantum computation largely depends on the stability of qubits, the new improved qubits should drastically improve the performance of future quantum computers. Artist’s impression of a single-atom electron spin, hosted in a silicon crystal and dressed by an oscillating electromagnetic field

The Australian university seems to be at the very forefront of quantum computing research. The UNSW was also recently responsible for proving that it could build quantum chips in silicon, just as regular chips are. The research showed that one day quantum computation might not happen just in special computers that need liquid nitrogen cooling or high-end lasers, but also in mass-market devices such as our PCs and smartphones.

### “Dressed” Qubits

The recent discovery, made by a team led by Professor Andrea Morello from the School of Electrical Engineering and Telecommunications at UNSW, brings silicon quantum computers much closer to reality. This is possible due to the invention of the new type of qubits called “dressed qubits,” which are qubits subjected to an electromagnetic shield to protect them from external interference.

“We have created a new quantum bit where the spin of a single electron is merged together with a strong electromagnetic field,” said Arne Laucht, a Research Fellow at the School of Electrical Engineering & Telecommunications at UNSW, and lead author of the paper.

“This quantum bit is more versatile and more long-lived than the electron alone, and will allow us to build more reliable quantum computers,” he explained.

Quantum computers are not going to replace conventional computers. However, they should be capable of doing highly complex calculations, such as the design of a new drug or material, that are either many orders of magnitude slower, or even impossible, to execute on regular computers.

### Electromagnetic Noise Protection

The new qubits last for 2.4 milliseconds before they are dephased, which is an order of magnitude longer than what was previously possible. The researchers achieved the goal by using an electromagnetic field that oscillates continuously and steadily at a high frequency, which cancels out any other disturbance with a different frequency.

Laucht said that the reason these “dressed” qubits are so much more resilient to external noise is because they control the quantum information by the frequency in the same way an FM radio is controlled. This is unlike the undressed qubits, which require turning the amplitude of the control fields on and off, just like with an AM radio. Because they can only be turned on and off, the undressed qubits are much more sensitive to external noise.

### Quantum Race Accelerating

The race for making the first practical universal quantum computer seems to be speeding up lately. Google also promised to announce a 50-qubit quantum computer, and IBM recently gave developers access to its 5-qubit computer, too.

The jury is also still out on the usefulness of D-Wave’s own quantum annealing computer. For now, it has only shown to be good at making quantum annealing operations orders of magnitude faster compared to a single-core PC, but so far, these operations haven’t proven to be too useful.

The University of Waterloo also intends to build a 100-qubit quantum computer over the next seven years. There also seem to be more and more universities securing increased funding to construct quantum computing research laboratories, which should only accelerate how fast quantum computing

Understatement of the year. You could have 1billion CPU cores and DWave would still be 2 orders of magnitude faster.

Searching "recommended rsa key strength" on Google:

RSA claims that 1024-bit keys are likely to become crackable some time between 2006 and 2010 and that 2048-bit keys are sufficient until 2030. An RSA key length of 3072 bits should be used if security is required beyond 2030. ... Thus, a 3072-bit Diffie-Hellman key has about the same strength as a 3072-bit RSA key.

Am I missing something?

Wouldn't only 13 qubits be needed to crack Google's beyond 2030 projection?

The general idea is that if you want to find the answer to a 4096bit question, then you need to have enough qubit to hold the answer, which may itself be 4096bits in size. 13 qubits will at most give you an answer 13bits in size.

Most practical use for quantum computing is AI.

Indeed quantum computers could be massively faster in cracking current encryption, but by that time we could also be using quantum encryption that is a whole other ballgame and cracking it (if it can be cracked) is not only a matter of compute resources.

According to whom?

D-Wave is privately held. Anyone who's not privately held is going to be big, like IBM and Google. So, not as much upside.