Nav: Home

Faster method to read quantum memory

February 25, 2019

The potential computing revolution that quantum computers have long promised is based on their weird property called superposition. Namely, qubits can take both logical states 0 and 1 simultaneously, on top of any value in between. By mastering superpositions of the whole quantum memory, quantum computers can quickly solve problems that would require too much computing time from regular computers working with simply 0s and 1s.

However, qubits are sensitive, and currently hold quantum information for less than a millisecond at a time, even when kept frozen at temperatures colder than the dark side of the moon. To extract any useful information, the method that reads information from qubits must take the least amount of time as possible, allowing as few errors as possible.

Joni Ikonen, a PhD student at Aalto University, has developed a new method that helps do just that. Until now, the method used to read information from a qubit was to apply a short microwave pulse to the superconducting circuit containing the qubit and then measure the reflected microwave. After 300 nanoseconds, the state of the qubit can be deduced from the behavior of the reflected signal.

The new method applies an extra microwave pulse at the same time to the qubit itself, as well as to the circuit attached to the qubit. By using two pulses instead of one, the team at Aalto was able to make the reflected pulse reveal qubit states substantially faster than when they only applied a single pulse.

Caption: The two quantum states, here represented by red and blue arrows, separate faster and can be read quicker when the system is pulsed with two microwaves

'We were able to complete the readout in 300 nanoseconds in our first experiments, but we think that going below 100 nanoseconds is just around the corner,' says Joni Ikonen.

By improving the speed and accuracy of the information retrieved from qubits, scientists may be able to move closer to realising the promise of useful quantum computing.

'This is an amazing result in getting the slippery qubits in order. I hope that it will help the community in the future to reach quantum supremacy and error correction, the path to a quantum computer of practical value,' says Dr. Möttönen, who co-supervised the work with Dr. Jan Goetz.
-end-
For further information contact:

MSc Joni Ikonen
Quantum Computing and Devices Group, PhD student
Aalto University
joni.2.ikonen@aalto.fi
Mobile: +358400539317
Languages: English, Finnish

Dr Mikko Möttönen
Quantum Computing and Devices Group, Group Leader
Aalto University
Mobile: +358505940950
mikko.mottonen@aalto.fi
Languages: English, Finnish

https://www.aalto.fi/department-of-applied-physics/quantum-computing-and-devices-qcd

Dr Jan Goetz
Quantum Computing and Devices Group, Research Fellow
Aalto University
jan.goetz@aalto.fi
Mobile: +358503003445
Languages: German, English

Aalto University

Related Quantum Computers Articles:

Study takes step toward mass-producible quantum computers
Study takes step toward mass-producible quantum computers.
Testing quantum field theory in a quantum simulator
Quantum field theories are often hard to verify in experiments.
Refrigerator for quantum computers discovered
Researchers at Aalto University have invented a quantum-circuit refrigerator, which can reduce errors in quantum computing.
New quantum liquid crystals may play role in future of computers
First 3-D quantum liquid crystals may have applications in quantum computing.
'Virtual' interferometers may overcome scale issues for optical quantum computers
A team of researchers from RMIT, the University of Sydney and UTS have devised an entirely new way of implementing large-scale interferometers that will dramatically miniaturize optical processing circuitry.
Further improvement of qubit lifetime for quantum computers
An international team of scientists has succeeded in making further improvements to the lifetime of superconducting quantum circuits.
Construction of practical quantum computers radically simplified
Scientists at the University of Sussex have invented a ground-breaking new method that puts the construction of large-scale quantum computers within reach of current technology.
New quantum states for better quantum memories
How can quantum information be stored as long as possible?
A new class of materials could realize quantum computers
Scientists at EPFL and PSI have discovered a new class of materials that can prove ideal for the implementation of spintronics.
New 3-D wiring technique brings scalable quantum computers closer to reality
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

Related Quantum Computers Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".