Researchers take a step towards turning interactions that normally ruin quantum information into a way of protecting it

A new method for predicting the behavior of quantum devices provides a crucial tool for real-world applications of quantum technology
Illustration of research
Illustration of non-Hermitian topology and open quantum systems. Image: Jose Lado/Aalto University.

Researchers have found a way to predict the behavior of many-body quantum systems coupled to their environment. The work represents a way to protect quantum information in quantum devices, which is crucial for real-world applications of quantum technology.

In a study published in Physical Review Letters, researchers at Aalto University in Finland and IAS Tsinghua University in China report a new way to predict how quantum systems, such as groups of particles, behave when they are connected to the external environment. Usually, connecting a system such as a quantum computer to its environment creates decoherence and leaks, which ruin any information about what’s happening inside the system. Now, the researchers developed a technique which turns that problem into its a solution.

The research was carried out by Aalto doctoral researcher Guangze Chen under the supervision of Professor Jose Lado and in collaboration with Fei Song from IAS Tsinghua. Their approach combines techniques from two domains, quantum many-body physics and non-Hermitian quantum physics.

Protection from decoherence and leaks

One of the most intriguing and powerful phenomena in quantum systems is many-body quantum correlations. Understanding these and predicting their behaviour is vital because they underpin the exotic properties of key components of quantum computers and quantum sensors. While a lot of progress has been made in predicting quantum correlations when matter is isolated from its environment, doing so when matter is coupled to its environment has so far eluded scientists.

In the new study, the team showed that connecting a quantum device to an external system can be a strength in the right circumstances. When a quantum device is host to so-called non-Hermitian topology, it leads to robustly protected quantum excitations whose resilience stems from the very fact that they are open to the environment. These kinds of open quantum systems can potentially lead to disruptive new strategies for quantum technologies that harness external coupling to protect information from decoherence and leaks.

From idealised conditions to the real world

The study establishes a new theoretical method to calculate the correlations between quantum particles when they are coupled to their environment. ‘The method we developed allows us to solve correlated quantum problems that present dissipation and quantum many-body interactions simultaneously. As a proof of concept, we demonstrated the methodology for systems with 24 interacting qubits featuring topological excitations,’ says Chen.

Professor Lado explains that their approach will help move quantum research from idealised conditions to real-world applications. ‘Predicting the behavior of correlated quantum matter is one of the critical problems for the theoretical design of quantum materials and devices. However, the difficulty of this problem becomes much greater when considering realistic situations in which quantum systems are coupled to an external environment. Our results represent a step forward in solving this problem, providing a methodology for understanding and predicting both quantum materials and devices in realistic conditions in quantum technologies,’ he says.

More information:

Jose Lado

Jose Lado

Assistant Professor
T304 Dept. Applied Physics
  • Published:
  • Updated:
URL copied!

Read more news

Aalto EIT Services - Javor
Press releases Published:

EIT Start-up stories: The expansion of Finnish start-up to France

A Finnish start-up specialising in nautical mobility, Bout settles in Paris to take in the French market
Aalto EIT Services - Javor
Research & Art Published:

EIT Jumpstarter 2023 (register before 16 April 2023)

Do you have an innovative idea and want to jumpstart your business?
Illustration: Juuli Miettilä.
Research & Art Published:

Avatars and genuine interaction

Aalto University’s researchers are contributing to the creation of redesigned maternity and child health clinics and positive childbirth experiences in their research projects. The visions seize the potential of technology, such as childbirth simulation in a 3D-video conference using an avatar, a virtual character. On the other hand, the researchers would also like to hold on to the best practices from the past, such as the traditional child health clinic card, genuine human interaction and the rotina tradition, visits by family and close-ones to meet the newborn and bring foods as a gift.
Research & Art Published:

Sahar Babaeipour dreams of entrepreneurship – but before that, she wants to graduate as a doctor

The doctoral research conducted by Sahar Babaeipour, a doctoral researcher at Aalto University’s Bioinnovation Center, aims at a more sustainable packaging industry.