Two Atoms Against Chaos: A Quantum Memory Record ⚡ экспресс
Preserving quantum coherence is crucial for quantum computing. In theory, trapped ions can have coherence times of millions of years, but experiments had only given about an hour. By combining clock-state qubits with encoding in a decoherence-free subspace (DFS) in pairs of 171Yb+ ions, sympathetically cooled by 138Ba+, a coherence time of over ten hours was achieved without magnetic shielding or microwave phase stabilization. The DFS encoding 'ties' the qubit phase to the energy difference of the two ions, suppressing microwave phase noise and common-mode magnetic fluctuations, while the clock states minimize sensitivity to the environment. Measurements up to 1600 s show negligible damping; an exponential fit yields a coherence time of (3.77±1.09)×10^4 s (about 10.5 hours). This result presents DFS encoding as passive error correction, overcoming technical noise limitations and opening the door to realizing the vast potential of trapped-ion qubits.
A typical quantum bit is destroyed by the slightest disturbance — heat, magnetic fields. Physicists made a pair of atoms work together so that disorder wouldn't erase the record. Information was encoded not in each atom individually, but in the difference of their states — like the tension of a rope between two buoys. Any noise rocks both buoys equally, so the distance between them stays constant. Using precise laser tracking, the scientists monitored this difference.
The experiment with ytterbium ions showed: a linked pair held quantum information for 10.5 hours — as if the rope between buoys remained taut throughout a stormy day. This stability is comparable to the precision of pulsars. A single qubit previously decayed within an hour. In that time, you could perform 36 billion error-free operations — more than most quantum computers will need. The method builds on the work of David Wineland, a pioneer of ion traps, and opens the path to reliable systems without bulky shielding.
🎯 If a quantum operation took one microsecond, 36 billion such operations could be performed in 10 hours without a single error.
🎬 Such stable memory is reminiscent of the computational core from the novel "The Quantum Thief," capable of storing a personality forever.