Finnish startup S-Transistors has raised €2.6M to build superconducting electronics that control quantum computers from inside the cryostat, right next to the qubits.
Lifeline Ventures, a Nordic early-stage investor, led the round with an angel joining in. The startup traces its roots to VTT, Finland’s technical research center, and builds superconducting transistors meant to switch signals fast while drawing almost no power at cryogenic temperatures.
The problem it targets is scaling. Today, most control electronics sit at room temperature and connect to the quantum chip through multiple bulky cables per qubit, a setup that is power-hungry and poorly scalable as processors grow. S-Transistors argues the clearest path for superconducting quantum computers is to bring classical control and interface hardware down into the cryostat beside the chip.
Its first product will be a multiplexer built on superconducting transistors, designed to plug into existing cryogenic setups for quantum device development and prototyping.
Co-founder and CEO Dr Heorhii Bohuslavskyi said the approach could unlock larger, more energy-efficient systems. The pitch has drawn attention in a European quantum hardware scene that has seen a wave of fresh capital in 2026, with investors betting that control infrastructure, not just the qubits themselves, will decide who scales first.
