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量子電腦 - 中研院物理研究所

量子電腦 - 中研院物理研究所

量子電腦 - 中研院物理研究所

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是 什 麼 使 得 量 子 電 腦 效 力 強 大<br />

(what makes quantum computer powerful)?<br />

• Exponentiality( 指 數 性 質 ): computational ti state t space is<br />

n<br />

exponential in the physical size of the system (2 ).<br />

• Quantum parallelism( 量 子 平 行 性 ): by using superposition<br />

of quantum states, the computer is executing the algorithm<br />

on all possible inputs at once.<br />

e.g., ψ = ( 00 + 01 + 10 + 11 ) / 2.<br />

• Complex amplitudes or Interference( 複 數 振 幅 或 干 涉 )<br />

• Quantum entanglement (composite systems) 量 子 糾 纏<br />

1 1<br />

Separable: 0 0 + 0 1 = 0 ⊗ 0 +<br />

2 2<br />

1<br />

Entangled : ( 0 1 − 1 0<br />

)<br />

≠<br />

ψ<br />

⊗<br />

φ<br />

A B A B A B<br />

2<br />

• More…<br />

( ) ( 1<br />

)<br />

A B A B A B B

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