Quantum computing startup QuEra has secured $230 million in funding from investors including Google and SoftBank, in a convertible note that will be converted into equity in the company's next funding round. The Boston-based company plans to use the funds to develop a "useful" fully-quantum computer within the next three to five years.

The financing is a significant boost for QuEra, which has previously raised just under $50 million. The company's COO, Yuval Boger, described the valuation as "a very substantial increase" compared to QuEra's previous round, although no specific valuation was provided. Industry observers estimate the valuation to be around $400 million.

QuEra's funding is part of a growing trend in the quantum computing space, with several startups securing significant investments in recent months. Alice&Bob, a Paris-based quantum computing startup, raised $104 million just two weeks ago, while Riverlane, a Cambridge-based company developing technology to correct quantum errors, raised $75 million. SEEQC, a quantum chip maker, raised $30 million in January, and Quantum Machines in Israel is reportedly raising $100 million.

QuEra's approach to quantum computing focuses on building a neutral atom quantum supercomputer, which uses lasers to cool atoms in the computing process to reduce errors. The company's interim CEO, Andy Ory, believes that QuEra's architectural approach will enable it to achieve "discontinuous quantum advantage" and deliver the first scalable, useful quantum computer.

The company has already made significant progress, with revenues generated from the sale of a QuEra quantum computer to Japan, which will be used in a new supercomputer project alongside Nvidia technology. QuEra has also been offering quantum compute services over AWS, with its 256-qubit computer being used for pilots and proof-of-concept experiments.

The funding from Google, which is supported by Google's Quantum AI business unit, does not include any tie-ins with the Google Cloud Platform. QuEra is exploring expanding its cloud services to other platforms, but has not announced any specific plans.

The long-term promise of quantum computing is a tantalizing one, with the potential to leapfrog traditional computing workloads and offer significant advantages in areas such as material science, life science, simulation, and optimization problems. QuEra's Ory believes that if the company can achieve 100 logical error-corrected qubits with the ability to run a million instructions without an error, there will be useful applications for quantum computing that offer advantages over regular computers.

While QuEra's funding is a significant milestone, the development of a fully-quantum computer remains a complex and challenging task. The company's flexible deadlines and focus on technical implementations will be crucial in achieving its ambitious goals. As the quantum computing space continues to evolve, QuEra's progress will be closely watched by industry observers and investors alike.