量子計算的歷史與前景 History and Perspective of Quantum Computation 撰文 Chinese & English│殷灝 Ian Hou 2016年8月，中國第一顆也是世界上第一顆量子衛星“墨子號”升空。2017年6月，世界上第一個地空量子信息實驗：一對 相距1,200公里的光子的量子糾纏，通過墨子號實現。2011年加拿大D-Wave公司以一千萬美元出售了世界第一套量子計算 機。2013年，谷歌成立了量子人工智能實驗室。2017年，IBM實現了50個量子比特的雲計算機。在過去的十年裡，量子信 息和量子計算這兩個名詞不斷地出現在人們的視野裡，那它們到底指的是甚麼呢？我們以後是不是就不用現在的電腦，而要 改用量子電腦了呢？ In August 2016, China’s first, and also the world’s first, quantum communication satellite ‘MoZi’ was launched. In June 2017, the world’s first experiment on quantum information across the earth and space – the separation of a pair of entangled photons over 1200km – was realised through the satellite. The first quantum computer was sold by the Canadian company D-Wave at a price tag of USD10 million in 2011. Google established its quantum AI lab in 2013. IBM made a 50 quantum-bit cloud computer in 2017. Over the past decade, the topics of quantum information and quantum computation have appeared constantly in media; but what do they really mean? Would we stop using the current computers and switch to quantum computers in the future? 概率算法和平行計算 故事要從上世紀講起。1947年晶體管和50年代集 成電路發明後，計算機的計算能力大增，科學家 開始利用新增的計算能力來處理人力基本處理不 了的問題，例如將一個大數因子化，通過特殊函 數的計算將訊息加密等。為了減低計算複雜度， 提高計算速度，將原來需要幾天計算時間的程式 壓縮到幾分鐘內完成，科學家在70年代提出了一 種“概率算法”來增加程式的平行併發度。 Probabilistic Algorithm and Parallel Computing To answer these questions, we have to begin our story in the last century. With the invention of the transistor in 1947 and the integrated circuit in the 1950s, the power of computers greatly increased. Computer scientists made use of the newly acquired power to solve problems that are beyond the calculation capacity of humans, such as factoring large integers or encrypting messages by scrambling some special functions. To reduce computation complexity and thus elevate the computing speed in these tasks, the scientists proposed what they called ‘probabilistic algorithms’ to compress the computing time from days to minutes by increasing the parallel concurrence in the algorithms. 學院專欄 FACULTY COLUMN umagazine issue 19 58
RkJQdWJsaXNoZXIy MTQ1NDU2Ng==