News

Welcome to Daniel

With some delay we welcome Daniel as new group member! Daniel has graduated from Delft University of Technology, Netherlands where he specialized in low temperature superconducting and semiconducting quantum physics. We all hope Daniel will have a smooth start at UQ.

Contextuality covered

Our newly published experiment was covered on the EQUS website

2016 UQ Foundation Research Excellence Awards (UQ FREA)

Arkady Fedorov was awarded a prestigious UQ Foundation Research Excellence Award for 2016. 

Arkady Fedorov - UQ Foundation Research Excellence Award Winner from The University of Queensland on Vimeo.

Andres wins poster award for 2016

The School of Mathematics and Physics at UQ holds annual poster competition. Andres Rosario wins the award this year! The poster was dedicated his on-going experimental project for realizing microwave diode with two superconducting qubits. An award also come swith some small funds for future conferences.

Confirmation and new start

In July-August there have been two important events in our group. Andres Rosario has easily passed his confirmation. Anatoly Kulikov who visited us previously in December 2015- February 2016 has been awarded UQ International Scholarship and started his PhD in our lab. Congratulations to Andres and welcome to Anatoly!

Qubits as an art tool

Qubits placed in a open waveguide may play a role of mirror for microwave radiation. These are not standard mirrors though as the reflectivity is frequency and power dependent. If there are more than one qubit in a waveguide these properties may give rise interesting effects (for the first experiments with two qubit in a waveguide see this paper). But else they can be good for? Following the idea of Arjan van Loo we can use qubits for drawing pictures!

How to cool a mm-size mechanical resonator to its ground state

We have uploaded a theoretical proposal proposal on cooling the large quartz reosnator by coupling it to a superconducting qubit. Unlike nanomechanical oscillators Bulk Acoustic Wave (BAW) oscillators offer exceptional mechanical properties such as extremely high quality factors. Yet them coupling to qubits it is not easy due to unavoidable large stray capacitance. Our paper investigates a possible solution to this problem which should allow to cool BAW oscillator to its ground state.

Can you have high quality factor and magnetic control for 3D microwave cavity?

Three-dimensional (3D) superconducting microwave cavities have exceptional quality factors but do not allow magnetic field to penetrate inside them. It is also hard to thermalize them to the cold stage of a dillution refrigirator. A copper cavity can be thermalized and allows for magnetic control but its quality factor is limited. In our new work we tried to reach a compomise between quality factor and magnetic tunability by creating "hybrid cavity" which consists of both superconductor and normal metal. Find out what were the outcomes in our new paper.

Superconducting circuits get contextual!

One of the biggest experimental efforts of our lab came finally to the end. We used all the advances we developed for superconducting circuits to probe quantum conetxtuality first time for superconducting circuits. Contextuality is one of the most fundamental properties of quantum mechanics, distinguishing it from classical physics without a need for nonlocality or entanglement. It is also a critical resource for exponential speedup in universal surface-code quantum computing. Our result is the first experiment violating a noncontextuality inequality with an indivisible system where entanglement cannot be defined which also addresses all known major loopholes, such as the detection, compatibility and individual-existence loopholes. Violating noncontextuality with superconducting circuits, a leading candidate for implementing surface-code quantum computing, comprises an important conceptual milestone in demonstrating their suitability for quantum technological applications.

Qutrit under control

Check out what one can do with a sperconducting qutrit: create quantum states, perform quantum tomography of these states and even quantum process tomography for the measurement. More importantly one can even probe one level of the qutrit while not disturbing two others.

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