Researchers at the University of Chicago have extended the lifetime of a quantum bit, or qubit, by using a novel technique to stabilize its fragile quantum state. The new technique, which is described in a paper published in the journal Nature, could lead to more robust quantum computers and better sensors.
The qubit is a fundamental building block of quantum computing, and its stability is essential for any practical quantum system. However, qubits are notoriously difficult to control and are prone to errors. The new technique, known as stabilized asymmetric readout (StAR), uses a small amount of electrical power to correct for these errors.
“Our technique can be thought of as a way to add a ‘quantum error-correction code’ to a qubit, without increasing its size or complexity,” said David I. Schuster, the Frank L. Sulovitch Distinguished Service Professor in Physics at the University of Chicago and a senior scientist at Argonne National Laboratory.
The StAR technique could be used to improve the performance of existing quantum devices, or to enable new types of quantum devices. For example, the technique could be used to develop more sensitive sensors that can detect very weak signals.
“This is an exciting new direction for quantum sensing,” said Irfan Siddiqi, the Pritzker Director of the Institute for Molecular Engineering at the University of Chicago and a senior scientist at Argonne. “Our technique could lead to sensors with vastly improved sensitivity and accuracy.”
The StAR technique could also be used to improve the performance of quantum computers. Quantum computers are hypothetical devices that could solve certain problems, such as factoring large numbers, much faster than classical computers.
“Our technique could be used to help build a practical quantum computer,” Schuster said. “It is a small step, but an important one.”
The StAR technique is based on a property of superconducting circuits known as flux Pioneering work on flux qubits by John Martinis and his group at Google established that these devices can be used to build scalable quantum computers.
The key to the StAR technique is that it can be applied to any type of qubit, not just flux qubits. This makes it a very versatile tool for correcting errors in quantum devices.
“One of the great advantages of our technique is that it is compatible with a wide variety of qubit technologies,” said Siddiqi. “This will give us a lot of flexibility as we continue to explore the quantum frontier.”
July 21, 2020 – Quantum computers are notoriously difficult to control and operate due to their fragility. In new research, scientists have found a way to stabilize qubits, the fundamental building blocks of quantum information processing.
In a paper published in the journal Nature, an international team of researchers describe how they used a novel technique called dynamical decoupling to extend the lifetime of a qubit by a factor of 10,000. This is a breakthrough in quantum computing research, as it enables the development of larger and more complex quantum computers.
Dynamical decoupling is a way of protecting qubits from errors by constantly resetting them. The team used a similar technique to stabilize the qubits in a previous study, but this time they were able to extend the lifetime of the qubits by 10,000 times.
The research was conducted by scientists at the University of Innsbruck in Austria, the University of Illinois at Urbana-Champaign in the United States, and the Technical University of Munich in Germany.
This is a significant breakthrough in quantum computing research, as it paves the way for the development of larger and more complex quantum computers. The next step is to scale up the size of the quantum computer and to show that the technique can be applied to multiple qubits.
