時間結晶（Time Crystal）
時間の中でパターンが繰り返される物質の状態。
Proposed by Nobel laureate Frank Wilczek in 2012, time crystals were first observed in 2016. They exist in 'floquet' non-equilibrium phases where the system's internal state repeats at a period that is an integer multiple of the driving period. This perpetual motion (in the ground state, not doing work) challenges standard thermodynamics and has potential applications in stable quantum memory.
graph LR
Center["時間結晶（Time Crystal）"]:::main
Rel_iteration["iteration"]:::related -.-> Center
click Rel_iteration "/terms/iteration"
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classDef child fill:#0f172a,stroke:#10b981,color:#94a3b8,rx:5,ry:5;
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🧒 5歳でもわかるように説明
「電池がないのにずっと動き続ける時計」のようなものです。ダイヤモンドのような普通の結晶は、粒子の並び方に「場所」のパターンがありますが、時間結晶は「時間」のパターンが永遠に繰り返されます。揺らしても止まらない不思議なゼリーのようなイメージです。
🤓 Expert Deep Dive
Time-crystals are a manifestation of 'Discrete Time-Translation Symmetry Breaking' (DTTB). In a periodically driven (Floquet) many-body localized (MBL) system, the response of the system shows a sub-harmonic frequency, meaning it returns to its state after $ n imes T $ where $ T $ is the driving period. This rigidity against perturbations makes them candidates for high-coherence qubits since they are immune to thermalization.