Remote Entanglement Between a Superconducting and a Spin Qubit

We are in the midst of a second quantum revolution based on controlling and manipulating of individual quantum states of atoms, ions, quantum dots or photons in microscopic systems. Quantum computers can solve complex problems exponentially faster than classical counterparts which is necessary to advance medicine, engineering, logistics, chemistry and other fields. Extremely secure communications and faster code breaking based on quantum innovations are essential for European technological sovereignty. Europe’s leading scientific position will rely on quantum computers, simulators and sensors, interconnected via quantum networks distributing information and quantum resources. However, the current state of quantum technology necessitates that many separate systems work independently of one another. The Superspin project's end goal is to establish the technology needed to optically link a superconducting quantum computer and a spin-based quantum memory, both of which function at very different frequencies. We need to convert signals from the microwave to the optics and the visible wavelength to the telecom regimes, and to do so we will be developing novel components operating at the single photon level. We will also create an optical quantum memory and a qubit chip based on superconducting technology that can communicate with such convertors. In Superspin, we will show that a quantum state from a superconducting qubit can be stored in a spin qubit, marking the first demonstration of this concept. With Superspin, we facilitate the scaling of quantum technology by allowing individual systems to interact with one another remotely, rather than relying solely on the construction of ever-larger isolated systems. By providing a primary building block for the interconnection of quantum processors, quantum memories, quantum sensors, and quantum repeaters over an optical network, our technological breakthrough creates new opportunities for European quantum technology platforms.