Research in quantum computing and simulation

The main project within Wallenberg Centre for Quantum Technology is to build a superconducting quantum computer with at least one hundred well-functioning qubits. The quantum computer is developed in a targeted project at Chalmers.


This page describes quantum computing research performed within WACQT. For a general introduction to quantum computing, please go to page Quantum computing.

In WACQT, we have chosen to base our quantum computer on superconducting circuits, the same technology pursued by the current world leaders in quantum computing: Google, IBM, and Rigetti Computing (a venture-backed startup in California). Chalmers researchers already have extensive experience and expertise when it comes to manufacturing and working with superconducting qubits. Advantages of super conducting qubits include: 

  • In superconductors, the quantum levels representing the values 0 and 1 are separated by a large gap. This means that low-energy noise, such as thermal noise, cannot cause the qubit to change its value.
  • The superconducting circuits that constitute the qubits can be designed and manufactured on a chip, similar to an ordinary microchip. The manufacturing method allows for scaling up to a large number of qubits and provides flexibility in how to inter-connect them.
  • Superconducting qubits are controlled and manipulated using microwaves – a frequency band in which a lot of good equipment is already available.
  • Quantum-logical operations can be performed very quickly in superconducting circuits, at least a hundred times faster than in an ion trap.

In the first couple of years, we have been working, completely according to our plan, with a chip with only two qubits. Our strategy is to first get it to work really, really well on a small scale, before scaling up in fairly large steps. 

“Our two-qubit gates are now as good as those of the world-leading groups in quantum computing. As our qubits already have very good lifetimes, we have now reached good enough performance to build larger systems with more qubits”, said Philip Krantz, project coordinator in WACQT, in November 2019.

An important task for our theorists is to explore what a relatively small quantum computer could do and try to find "a killer" application – that is to find the first useful problems, that are beyond the reach of regular computers, that a relatively small quantum computer can solve. We are working hard on this in collaboration with our industrial partners.

Our quantum computing team is also part of OpenSuperQ – a large European effort to build a superconducting quantum computer and make it available in the cloud. Read more​ in Joining forces for a European quantum computer.

 

Leaders of experimental efforts in quantum computing and simulation:

Per Delsing, per.delsing@chalmers.se, +46 31 772 3317

Jonas Bylander, jonas.bylander@chalmers.se, +46 31 772 5132

 

Leader of theoretical efforts in quantum computing and simulation:

goran.l.johansson@chalmers.se, +46 31 772 3237

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Published: Wed 18 Mar 2020.