Ultra-Cold Quantum Cooling Breakthrough

Quantum computers rely on quantum bits, or qubits, which must be kept at extremely low temperatures – near absolute zero – to function properly. However, the electronic components that control these qubits generate heat, which is difficult to remove at such frigid temperatures. Current solutions involve separating the quantum circuits from their controls, leading to noise and inefficiencies that limit the potential of quantum systems.

The team at EPFL’s Laboratory of Nanoscale Electronics and Structures LANES has created a device that operates efficiently at ultra-low temperatures, matching the performance of room-temperature technologies.

This innovative device combines graphene’s excellent electrical conductivity with indium selenide’s semiconductor properties. Only a few atoms thick, it functions as a two-dimensional object, and this unique combination of materials and structure enables its unprecedented performance. The research has been published in Nature Nanotechnology.

Harnessing the Nernst Effect in Extreme Cold

The device works by exploiting the Nernst effect, a complex thermoelectric phenomenon that generates electrical voltage when a magnetic field is applied perpendicular to an object with a varying temperature. The two-dimensional nature of the device allows for electrical control of this mechanism’s efficiency.

The team fabricated the 2D structure at EPFL’s Center for MicroNanoTechnology and the LANES lab. They used a laser as a heat source and a specialized dilution refrigerator to reach temperatures of 100 millikelvin – even colder than outer space. Converting heat to voltage at such low temperatures is typically extremely challenging, but the novel device makes this possible, filling a critical gap in quantum technology.

“If you think of a laptop in a cold office, the laptop will still heat up as it operates, causing the temperature of the room to increase as well. In quantum computing systems, there is currently no mechanism to prevent this heat from disturbing the qubits. Our device could provide this necessary cooling,” Pasquale explains.

Pasquale emphasizes that this research is significant because it sheds light on thermopower conversion at low temperatures – an underexplored phenomenon until now. Given the high conversion efficiency and the use of potentially manufacturable electronic components, the LANES team believes their device could be integrated into existing low-temperature quantum circuits.

“These findings represent a major advancement in nanotechnology and hold promise for developing advanced cooling technologies essential for quantum computing at millikelvin temperatures,” Pasquale says. “We believe this achievement could revolutionize cooling systems for future technologies.”

This breakthrough could be a game-changer for quantum computing, potentially enabling the development of larger and more powerful quantum systems that can operate outside of specialized laboratory environments.