The world of quantum computing is making significant strides, but there are still major obstacles to overcome in order to fully harness its potential impact on society.
One of the biggest challenges faced by quantum researchers is the issue of errors and noise disrupting sensitive qubits, causing them to lose their quantum state and rendering them unable to continue computing. This has limited the effectiveness of quantum computers up until now.
In addition, controlling quantum states is essential for quantum computers to tackle complex problems. Without a proper control system, quantum states are like a car without a steering wheel – they lack the ability to be efficiently manipulated.
Researchers at Chalmers University of Technology have recently developed a groundbreaking system that addresses this dilemma, paving the way for longer computation times and more robust quantum computers.
“We have created a system that enables extremely complex operations on a multi-state quantum system at an unprecedented speed,” explains Simone Gasparinetti, senior author of the study.
Unlike traditional computers that use “bits” with values of 1 or 0, quantum computers utilize “qubits” that can exist in states of 1 and 0 simultaneously, thanks to a phenomenon called superposition. This ability allows quantum computers to perform calculations simultaneously, granting them immense processing power.
However, qubits encoded in physical systems are highly susceptible to errors, prompting researchers to seek solutions. The system developed at Chalmers University of Technology leverages resonators and microscopic components to linearly encode information within a quantum computing continuum.
This innovative approach, based on quantum principles, enhances error correction and computation times while maintaining control over quantum states. The use of a microwave resonator made of superconducting materials aligns with cutting-edge superconducting quantum computer technology.
“Think of a qubit as a blue lamp that can be switched on and off simultaneously, while a continuous variable quantum system is like an infinite rainbow, providing a vast array of states for richer possibilities,” says Axel Eriksson, the lead author of the study.
Although oscillator-based continuously variable quantum computing may increase error rates, it enables complex operations. Previous attempts to combine resonators with control systems were hindered by the Kerr effect, which interfered with the quantum states provided by the oscillator.
By embedding control devices within the oscillator, researchers at Chalmers University of Technology overcame the Kerr effect, allowing for precise control of quantum states at high speeds. This breakthrough, detailed in a paper published in Nature Communications, opens up new possibilities for quantum computing.
“Our work challenges the conventional wisdom of keeping superconducting elements away from quantum oscillators to preserve quantum states. By incorporating a control device within the oscillator, we can manipulate quantum states without compromising their integrity, leading to high-speed gate operations,” says Simone Gasparinetti.
