PsiQuantum is a California-based company that is developing a quantum computer using photonics technology. The company's goal is to build a fault-tolerant quantum computer with millions of qubits, which would be capable of solving problems that are currently intractable with classical computers. PsiQuantum was founded in 2016 by a team of experts in photonics, quantum computing, and computer science. The company has received funding from investors such as BlackRock, Founders Fund, and Atomico.