The chip is codenamed Helium 1 and contains 16 qubits to test out Alice & Bob’s cat qubit architecture for achieving a very high fidelity logical qubit. The term “tape out” means that the company has finished the design and sent the design files to a fabrication facility for construction. After the chip has been built, it will undergo extensive testing, characterization, and calibration by the company’s engineering team to realize the optimum performance and then made available for external use by the company’s customers. Any lessons learned during this process will be utilized in the design of the next chip so that even better characteristics can be achieved.
Alice & Bob’s cat qubit approach is different from what other companies are pursuing. In a quantum computer there are two basic types of errors that can occur, bit-flips and phase-flips. So conventional quantum error codes, like the surface code, need to be design to correct both types of errors. In the Alice & Bob architecture, the bit flips are nearly eliminated by the hardware architecture that they use so that their error codes only need to correct for phase flips. A key advantage of this approach is that it could significantly reduce the number of physical qubits needed to produce a logical qubit by as much as 60 times and enable much smaller machines to achieve quantum utility on real world problems. Assuming this chip is successful in meeting its goals, it will represent just one of a series of many more steps that will be needed to achieve a truly useful fault tolerant quantum computer.
A press release announcing the tape out of the Helium 1 chip can be accessed here.
December 20, 2023