Coupling of magnetism and microwaves to reduce noise in quantum information


Researchers from Argonne have demonstrated a quantum circuit on a chip and achieved a strong coupling between a superconducting resonator and a magnetic device. This earlier research introduced a new platform to study quantum information processing. Credit: Image by Ellen Weiss / Laboratoire national d’Argonne

A Department of Energy funded project between Argonne and the University of Illinois Urbana-Champaign explores the coupling of magnetism and microwaves for quantum discoveries.

The US Department of Energy (DOE) recently funded both the DOE’s Argonne National Laboratory and the University of Illinois Champaign-Urbana (UIUC) in a new project related to quantum information science . The Argonne team will bring to the project its expertise in the coupling of superconducting and magnetic systems. The UIUC team will bring its world-class capabilities to the development of new magnetic materials for quantum systems.

“Quantum information science promises new and different ways in which scientists can process and manipulate information for detection, data transfer and computation,” said Valentine Novosad, senior scientist in the Materials Science division of ‘Argonne. “The UIUC is an ideal partner to enable us to make revolutionary discoveries in this field. “

In the emerging field of quantum information science, microwaves can play a fundamental role because their physical properties allow them to provide the desired quantum functionality at temperatures close to absolute zero (minus 460 degrees Fahrenheit) – a necessity because heat creates errors in quantum operations. However, microwaves are sensitive to noise, which is unwanted energy that disrupts signal and data transmission.

“Quantum information science promises new and different ways in which scientists can process and manipulate information for detection, data transfer and computation. “- Valentine Novosad, Materials Science Division

The research team will examine whether magnons could associate with microwave photons to ensure that microwaves can only travel in one direction, essentially eliminating noise. Magnons are the fundamental excitations of magnets. In contrast, microwave photons result from electronic excitations producing waves like those in a microwave oven.

Scientists at Argonne will build on their earlier efforts to create a superconducting circuit integrated with magnetic elements. Magnons and photons speak to each other through this superconducting device. Superconductivity – the total absence of electrical resistance – allows the coupling of magnons and microwave photons at a level close to absolute zero.

“This ability presents unique opportunities for manipulating quantum information,” explained Yi Li, a post-doctoral fellow in Argonne’s Materials Science division.

In the past, Argonne has played a major role in the development of superconducting detectors and sensors to understand how the universe works at the most fundamental level. “We will benefit from the valuable knowledge gained from these very successful projects in cosmology and particle physics,” said Novosad.

UIUC researchers will be looking for magnets that operate at ultra-cold temperatures. They will test known and new material systems to find candidates capable of handling an ultra-cold environment and operating in a true quantum device.

“Many magnets work well with room temperature microwaves,” said Axel Hoffmann, founding professor of engineering at UIUC and responsible for this project. “We need materials that also perform well at much lower temperatures, which can completely change their properties. “

“If we are successful in these three years, we will have magnetic structures directly integrated into quantum circuits,” Hoffmann said. “This work could also apply to non-quantum sensing and communication devices, such as Wi-Fi or Bluetooth technologies.”

This new project is another example of how Argonne and the UIUC are paving the way for a quantum future. Argonne not only conducts interdisciplinary research within its broad portfolio of QIS projects, but also leads Q-NEXT, one of five QIS DOE research centers established in August 2020. Likewise, UIUC supports a wide range of quantum information projects, such as Q-NEXT, through the Illinois Center for Quantum Information Science and Technology (IQUIST).

The DOE Office of Basic Energy Sciences is funding this 3-year project to the tune of $ 4.2 million. Argonne’s earlier research related to superconducting devices had been funded by the DOE’s nuclear physics and high-energy physics programs.

Besides Hoffmann, Li and Novosad, the team includes Wolfgang Pfaff, André Schleife and Jian-Min Zuo from UIUC.


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