First Cat-Qubit Chip Available to the Public on Google
With a bit-flip lifetime exceeding seven minutes, the Boson 4 cat-qubit quantum chip bests other superconducting qubits.
Alice & Bob, a leader in fault-tolerant quantum computing, has launched the first publicly available cat-qubit quantum chip, Boson 4, on Google Cloud Marketplace.
Alice & Bob’s Boson cat qubit joins other investments the company is making in quantum computing, including its multi-qubit chips Hydrogen, which detects quantum errors, and Helium, which exponentially removes phase flips through error correction.
Boson alongside Alice & Bob's other line-up of multi-qubit chips, Hydrogen and Helium.
What Is a Cat Qubit?
A cat qubit is a supercomputing qubit that leverages two states at once—nodding to Schrodinger’s cat being both alive and dead at the same time.
For a typical superconducting qubit, only one phase and one amplitude are encoded. If the amplitude for a superconducting qubit is α, the quantum state is either +α or -α, but not both. A cat qubit exists in the states +α and -α at the same time and always includes one amplitude encoded twice.
Improvements in bit-flip time from Alice & Bob’s Boson 1 to Boson 4 highlight the trade-off of exponentially decreasing bit-flip errors while linearly increasing phase-flip errors.
Cat qubits present an interesting trade-off in quantum computing that is not observed in superconducting bits. Cat qubits can exponentially decrease in bit-flip error rates and linearly increase in phase-flip error rates, while superconducting bits experience both bit-flip and phase-flip errors at higher rates.
The Boson 4 Tackles Bit-Flip Errors
Two general errors affect qubits in quantum computers: bit-flip errors and phase-flip errors. Alice & Bob aim to improve bit-flip errors with Boson 4 and plan to address phase-flip errors in the future. A bit-flip error changes the state of a qubit from |0⟩ to |1⟩ or vice versa, similar to classic computing when a bit flips from 0 to 1 or 1 to 0.
Dozens of bit-flip and phase-flip errors occur per second in quantum computing. Boson 4 extends the bit-flip time to well over seven minutes. This is a 4x improvement from state-of-the-art superconducting qubits, setting a new world record for bit-flip lifetime.
What Boson 4 Means for Quantum Research
Because Boson 4 affords bit-flips a longer lifetime, bit-flip errors rarely occur and don't require correction. Paired with a low-density parity check (LDPC), Boson 4 increases the number of qubits required to build a fault-tolerant quantum computer by up to 200 times.
By making Boson 4 available to the public via Google Marketplaces, Alice & Bob hopes to help democratize quantum research. A broader range of researchers and institutions can experiment without making substantial hardware investments, which may, in turn, accelerate achievements in fault-tolerant quantum computing.
Because fault tolerance is seen as a mandatory achievement in quantum computing, Boson 4 and similar quantum computing hardware can potentially change industries with life-altering discoveries in chemistry, biotechnology, cryptography, and artificial intelligence.
All images used courtesy of Alice & Bob.
