New qubit tech traps single electrons on liquid helium

In the race to develop functional quantum computers, numerous technologies have emerged as frontrunners, with several companies successfully constructing machines featuring dozens to hundreds of qubits. As they advance, the focus has shifted from fundamental scientific challenges to complex engineering hurdles. Remarkably, even at this advanced stage, new contenders are entering the arena with innovative qubit technologies, aiming to create breakthroughs that could change the industry's landscape. A recent publication from EeroQ, a pioneering company in this field, details an intriguing qubit system that utilizes single electrons suspended on a layer of liquid helium. To understand the mechanics behind this phenomenon, we spoke with Johannes Pollanen, EeroQ's chief scientific officer. He explained that this concept, while appearing novel, is based on established physics principles first demonstrated over fifty years ago. Pollanen elaborated, "When a charged particle, such as an electron, approaches the surface of the liquid helium, it induces a minor image charge beneath the surface due to the dielectric properties of the helium. This results in a weaker positive charge that interacts with the electron, effectively binding it to its own image. The electron is attracted to this positive charge but cannot reach it due to helium's chemically inert nature, which leaves no available spaces for it to occupy." Achieving the necessary conditions for this experiment requires extremely low temperatures, yet liquid helium can remain in its liquid state up to 4 Kelvin. This temperature threshold eliminates the need for the advanced refrigeration systems typically required for technologies like transmons, while also creating a near-perfect vacuum in the container, as almost all other materials will condense onto its walls. EeroQ's groundbreaking work not only sheds light on the feasibility of this qubit technology but also promises to pave the way for future advancements in the quantum computing domain.