Saturday , April 17 2021

Australian scientists to achieve a compact, sensitive qubit readout



The authors, from left to right: a doctoral candidate Mark R. Hogg; Professor Michelle Simmons; Post Doc Matthew G. House; Graduate student Prasanna Pakkiam; Post Doc Andrey Timofeev

The authors, from left to right: a doctoral candidate Mark R. Hogg; Professor Michelle Simmons; Post Doc Matthew G. House; Graduate student Prasanna Pakkiam; Post Doc Andrey Timofeev

The group led by Australian of the Year, Michelle Simmons, overcame another important technical bar & # 39; er to build silicon-based quantum computer.

Simmons' team at UNSW Sydney has demonstrated a compact sensor to access the data stored in the electrons of individual atoms – a breakthrough that brings us one step closer to scalable quantum computing in silicon.

A study conducted in the framework of the Simmons group at the Center of Excellence for quantum computing and communication technologies (CQC2T) with a graduate student Prasanna Pakkiam as lead author, was published on November 27 in the journal Physical Review X.

Quantum bits (qubits or) made of electrons on individual atoms in semiconductors with & # 39 is perspective platform for large-scale quantum computers, due to their long-term stability.

READ: International scientists discuss silicon quantum computing in Australia

Creating qubits by accurately placing and sealing individual phosphorus atoms in the silicon crystal with 39 & # is the unique approach of Australian that Simmons team was leading worldwide.

But adding in all the compounds and gates needed to scale up the phosphorus atom of architecture is not to be a problem – until now.

"In order to control even a single qubit, you have to build multiple connections and gate around individual atoms, which are not very many places," said Simmons.

"Moreover, you need high quality qubits are in close proximity, so they can talk to each other – that is only achievable if you have as little gate of the infrastructure around them as possible."

Compared with other approaches for building a quantum computer, Simmons system already had a relatively low gate density. However, conventional measurement is still required at least 4 per qubit gates 1 and 3 to control it, to read it.

On the & # 39; yadnovvayuchy sensor is considered one of the control gate at UNSW team has been able to release it only two gates: one for management and one for reading.

Pakkiam lead author says, the system not only more compact, but due to the integration of the superconducting loop attached to the gate of the team now has a sensitivity to determine the quantum state of the qubit by measuring whether the electron moves between two neighboring atoms.

"And we have shown that we can do it in real time with a single measurement – one shot – to repeat the experiment and average the results without the need to," said Pakkiam.

Simmons said that it is because & # 39 is a significant step forward in the way we read the information embedded in our qubits.

"The result confirms that the single qubit gate reading now approaching the sensitivity necessary to perform the necessary quantum error correction for a scalable quantum computer," said Simmons.


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