Arq raises $1.4M pre-seed to build quantum internet repeater hardware in Barcelona

Arq (formally Arq Quantum Technologies), a Barcelona startup founded in 2025 by quantum scientists Samuele Grandi and Emanuele Distante, has raised $1.4 million (approximately €1.3 million) in a pre-seed round led by Ground State Ventures, with participation from Big Sur Ventures. The capital will fund laboratory setup and continued development of the company's quantum repeater hardware.

Arq is building what a quantum internet needs before anything else: a reliable mechanism for sending quantum information across distances. Classical internet signals degrade in transit and can simply be amplified; quantum states cannot be amplified without destroying the information they carry. Quantum repeaters solve this problem by creating and storing quantum entanglement at intermediate nodes, then extending it across a network hop by hop. Arq's approach uses rare-earth doped crystal quantum memories — crystals that can absorb and re-emit single photons at low temperatures — combined with photon-pair sources and temporal and spectral multiplexing, a technique that allows multiple photons to be processed simultaneously, increasing the throughput of quantum communication without requiring new fibre infrastructure.

The hardware that isn't a product yet

Quantum networks are not a near-term commercial category. Grandi and Distante demonstrated a multiplexed telecom-compatible quantum repeater in academic settings before founding Arq; translating that result into a reliable, reproducible device is a fundamentally different problem. "Our technology could lay the groundwork for quantum-exclusive networks that allow the impact of quantum technology to scale exponentially," said Distante — a description that is accurate as a long-range vision and not a near-term commercial claim.

The applications the company targets — telecommunications, financial services, pharmaceuticals, healthcare — are industries that would benefit from quantum-secure communication across long distances. The commercial timeline for that demand is measured in years, not quarters. This round is not buying market penetration; it is buying the laboratory setup and device characterisation that are required before any of the later questions can even be asked.

The geography of the bet

Quantum repeater hardware development has been concentrated in American and British academic labs and in the Netherlands, where quantum networking has government-backed infrastructure status. A Barcelona-based company raising from Ground State Ventures — a fund focused specifically on quantum technology — signals that specialist quantum capital is beginning to distribute itself across European geographies rather than concentrating in the already-established quantum clusters.

The pre-seed milestone is narrow: establish a working laboratory, demonstrate consistent device performance at telecom wavelengths, and show that the rare-earth crystal memory approach can be characterised and improved iteratively. That is a purely scientific goal. The commercial one is much further out — and Arq, at $1.4 million, is not pretending otherwise.