Research Gives New Insights for Improvement on Quantum Transport from the Singapore University of Technology and Design
Quantum transport is a well-studied but complicated concept. It’s had around 100 years of past studies and research focused on its dynamics, yet there is still plenty to look into. The data for quantum transport systems as well as the systems themselves are incredibly complex, creating challenges for scientists. To try to understand these systems better, and suggest improvements, researchers from the Singapore University of Technology and Design (SUTD) collaborated with Instituto de Física da Universidade de São Paulo and Helmholtz-Zentrum Dresden-Rossendorf to review previous literature, understanding the evolution of quantum transport. Their findings, published in the Reviews of Modern Physics, suggest that there are many more improvements that can be discovered and developed in this field.
Studying Nanoscopic Systems
To fully understand the quantum transport systems, the SUTD researchers focused on only a few models. “We focused on systems that are predominantly one-dimensional, and at their edges, they are coupled to macroscopic baths, such as thermal baths with a well-defined temperature,” explained principal investigator Associate Professor Dario Poletti of SUTD. “The beauty of one-dimensional systems is that they can have properties which are very different from bulk materials, and thus exploring them one could find a way to design novel systems and devices.” Other models were studied as well, specifically for their interactions with new phases of matter (such as the Bose-Einstein Condensate), which can be utilized in quantum technology. As Poletti added: “In a good portion of the review, we also dedicated particular attention to strongly correlated systems, e.g. systems in which the electrons strongly feel the presence of other near-by electrons. In such systems, there can be an emergence of new phases of matter and new physical properties which also can give new opportunities for future technologies for the control of quantum transport.” With these two models, Poletti and his team were able to compare and contrast the dynamics and interactions happening within the systems.
To measure these different dynamics, they used a range of metrics. “We presented results on transport as a function of the length of the system, their coupling to the baths, the properties of the baths (e.g. their magnetization), the type and magnitude of interactions in the system, the type of excitations present (e.g. magnetization), the presence of disorder and the presence of other dissipative effects (e.g. the system is also coupled to other types of baths),” Poletti stated.
The Bigger Implications of Quantum Transport
Because quantum transport can play a key role in both classical and quantum computing, understanding quantum transport systems is crucial for implementing improvements to this next-generation technology. This study revealed many different avenues that other researchers and developers can take to try to improve these systems even further. As Poletti explained, “Some of these directions include the need for even better models and methods to theoretically study these systems, and also ways to explore them experimentally. The emergence of non-equilibrium phase transitions also deserves further attention, and systems with dimensionality larger than one, e.g., strongly correlated two-dimensional materials.” Poletti and his team believe that by improving these quantum transporters, many other devices and materials may be improved as well. “Quantum transport is already part of our daily life,” Poletti stated. “The question is how well we can control it. One way to significantly increases the control of transport is by using strongly correlated materials, where the strong interactions between its constituents allow the emergence of different phases of matter or phenomenology. For example, these interactions can turn a system from being ballistic to diffusive, or even an insulator. And interactions, as my team and I have shown in other works, can lead to great control in the directionality of the current, thus leading to diodes for magnetization and heat currents.” With further research needing to be done, Poletti and his team are hopeful that their work offers a path for other researchers to take to further advance this field of quantum transport.
Kenna Hughes-Castleberry is a staff writer at Inside Quantum Technology and the Science Communicator at JILA (a partnership between the University of Colorado Boulder and NIST). Her writing beats include deep tech, the metaverse, and quantum technology.