My company is making them. You just need to have a sufficiently resilient surface code, which means a single device with millions of physical qubits (the standard brute-force approach) or use a qubit architecture that is intrinsically noise-free by comparison, and only needs 15-50 physical qubits (what my company is doing, and our competitors). The industry as a whole is probably only a few years away from achieving this, in some form.
A "perfect" or "indefinitely stable" qubit sounds impossible. But so would a DRAM cell to an electrical engineer in the 40's. A DRAM cell continuously refreshes to maintain state, and as a result a single bit in RAM can have a mean time to failure measured in geologic time. Likewise a quantum error correction algorithm with a sufficiently large factor, driven continuously, will maintain qubit state indefinitely.
Electrical engineers in the 1940s already had "infinitely stable" memory in the form of delay lines and Williams tubes. Quantum error correction is incomparably more difficult than using digital bits.
Why is it that every time I read about quantum computers, fusion, and high energy density batteries, the word "just" seems extremely load-bearing, but results are like just, nowhere to be seen
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My company is making them. You just need to have a sufficiently resilient surface code, which means a single device with millions of physical qubits (the standard brute-force approach) or use a qubit architecture that is intrinsically noise-free by comparison, and only needs 15-50 physical qubits (what my company is doing, and our competitors). The industry as a whole is probably only a few years away from achieving this, in some form.
A "perfect" or "indefinitely stable" qubit sounds impossible. But so would a DRAM cell to an electrical engineer in the 40's. A DRAM cell continuously refreshes to maintain state, and as a result a single bit in RAM can have a mean time to failure measured in geologic time. Likewise a quantum error correction algorithm with a sufficiently large factor, driven continuously, will maintain qubit state indefinitely.
Electrical engineers in the 1940s already had "infinitely stable" memory in the form of delay lines and Williams tubes. Quantum error correction is incomparably more difficult than using digital bits.
Why is it that every time I read about quantum computers, fusion, and high energy density batteries, the word "just" seems extremely load-bearing, but results are like just, nowhere to be seen
What does indefinitely stable mean?