Amazon Uses Quantum 'Cat States' With Error Correction

An anonymous reader quotes a report from Ars Technica: Following up on Microsoft's announcement of a qubit based on completely new physics, Amazon is publishing a paper describing a very different take on quantum computing hardware. The system mixes two different types of qubit hardware to improve the stability of the quantum information they hold. The idea is that one type of qubit is resistant to errors, while the second can be used for implementing an error-correction code that catches the problems that do happen. While there have been more effective demonstrations of error correction in the past, a number of companies are betting that Amazon's general approach is the best route to getting logical qubits that are capable of complex algorithms. So, in that sense, it's an important proof of principle. Amazon's quantum computing approach combines cat qubits for data storage and transmons for error correction.

Cat qubits are quantum bits that distribute their superposition state across multiple photons in a resonator, making them highly resistant to bit flip errors. Transmons are superconducting qubits that help detect and correct phase flip errors by enabling weak measurements without destroying the quantum state. Meanwhile, a phase flip is a quantum error that alters the relative phase of a qubit's superposition state without changing its probability distribution. Unlike a bit flip, which swaps a qubit's state probabilities, a phase flip changes how the quantum states interfere, potentially disrupting quantum computations.

By alternating cat qubits with transmons, Amazon reduces the number of hardware qubits needed for error correction. Their tests show that increasing qubits lowers the error rate, proving the system's effectiveness. However, rare bit flips still cause entire logical qubits to fail, and transmons remain prone to both bit and phase flips. If you're still entangled in this story without decohering into pure quantum chaos, kudos to you!

Read more of this story at Slashdot.