如何看待Google宣布「our quantum computer really works」？

01-02

Google: We have proof that our quantum computer really works （Dec 9th, 2015）
參考：http://googleresearch.blogspot.co.nz/2015/12/when-can-quantum-annealing-win.html
Google announced a breakthrough in the field of quantum computing Wednesday. The company thinks it"s found a quantum algorithm that solves problems 100 million times faster than conventional processes. If confirmed, this discovery could not only lead to iRobot-style artificial intelligence but also advance the US space program by light years.

Back in 2013, Google and NASA went halvsies on a D-Wave X2 computing system. The D-Wave is supposedly the world"s first functional quantum computer, though experts both within and without the company have never been able to conclusively prove that the machine actually taps into the quantum realm to produce its calculations. That is, until now.
Google"s announcement Wednesday centers on "quantum annealing", a technique that determines the global minimum for a given function when presented with a set of potential solutions. In English, it figures out the best (ie most efficient) overall course of action to complete a task when given a set number of options. Scientists have been working on quantum annealers for a while now, though the two primary techniques, "simulated annealing" and "quantum monte carlo" are both just simulated systems running on conventional hardware. The D-Wave system, on the other hand, is hard-coded to run the quantum annealing algorithm on its quantum array.
The company recently tested the new QA algorithm in a proof-of-concept trial against conventional systems running the simulated annealing and monte carlo methods. The results are more than impressive. As you can see from the graph above, Google"s method beat out the other two quite handily, solving a function with 1000 binary variables up to 100 million times faster.
Google qualified these results as "intriguing and very encouraging" in its announcement, though the company has a long way to go before this research is ready for the consumer market. But once it is, hoo boy, get ready for a technological revolution. With it, AI researchers may be able to develop smarter, more responsive computer learning systems, NASA could use it to simulate rocket launches (or entire space missions) -- heck even the mundane material sciences could get a boost from this technology.

讀谷歌的論文，雖然他們證明了量子退火演算法比模擬退火演算法快一億倍，可是他們的所解決的問題，目前最優的經典演算法還是比量子演算法快。他們認為需要設計新的硬體設備，提升性能才能讓這個設備真的有用。所以，我覺得這篇論文就是向谷歌申請後繼經費用的。

他們後來找了一個NP-hard問題，Number Partitioning Problem (NPP），理論分析認為用量子退火演算法比現有的所有經典演算法快。問題是，這個問題不能用D-WAVE公司的設備來算。最後還是歸結為一句話，需要設計下一代的量子退火計算器，要更大量的投入。反正谷歌不缺錢，趕緊投下去吧！

我覺得對於我等凡夫俗子來說，看看圖更便於了解。。。

Google這個量子計算機叫D-Wave。

感受一下。

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媒體使用的「it actually works」，「it"s 100 million times faster than today"s PCs」等說法，確實是過度簡化和包裝了這個話題。

就像其他樓主說的，它只能在實驗條件下，在一些極少量的、非常具體的、被精心設計的計算任務中，超越傳統晶元。D-Wave的工程總監Neven說，量子計算想要有實際意義還非常困難。當然他也說量子計算將會特別適合解決深度學習的問題，讓Machine Learning變成Quantum Learning，AI將會通過量子計算實現。

現實科技的演進是一個漫長的過程，大家還是不要過度期望一個黑科技突然降臨。你以前要是曾經感受過黑科技突然降臨的感覺，只能說明你之前沒關注過那個領域而已。。。

對了，這一套系統成本超過1000萬美元。

給一句老美慣用的超官方回答：

「We』re not quite there yet, but we』re on the way.」

題主沒把圖貼出來，這裡轉個圖。

就從效果來看，降低了好幾個數量級，似乎挺牛b。不過……重點自己看吧

Hartmut Neven, the head of Google"s Quantum Artificial Intelligence lab, said these results are "intriguing and very encouraging" but that there"s still "more work ahead to turn quantum enhanced optimization into a practical technology."

As always, it"s important to note that D-Wave"s computers are not capable of universal computing: they are only useful for a small number of very specific tasks—and Google, NASA, and others are currently trying to work out what those tasks might be. D-Wave』s claim of "over 1,000 qubits" is also unclear. In the past, several physical qubits were clustered to create a single computational qubit, and D-Wave doesn』t make that distinction clear.

Google, NASA: Our quantum computer is 100 million times faster than normal PC

更新

汗……因為沒翻譯出來所以被反對了么？

not capable of universal computing 不適合通用計算

簡單解釋一下通用計算，免的又被反對了。通用計算對比非通用計算，就像是智能手機對比功能手機。功能手機能實現的功能，在出廠的時候就已經預設好了。但智能手機可以用軟體的形式實現功能手機的所有功能。如果還無法理解，那就想想計算器（非通用機）和個人電腦（同用機）吧。

用圖靈的原話說，通用機就是不僅能編程（非通用機的功能），而且能夠再編程。

有關這部量子計算機，知乎上已經有不少相關討論，可參考見：

https://www.zhihu.com/question/38345705 https://www.zhihu.com/question/34265075

https://daily.zhihu.com/story/4515604

https://www.zhihu.com/question/22506483/answer/38892366

然後，這新聞的意思是說用某個演算法在D-Wave上運算出來的確比一般計算機快上億倍。(看第二個連結的第一個答案[https://www.zhihu.com/question/34265075/answer/59375116]，之前有人測試說速度差不多)，現在算是回應了質疑了並顯示這東西的確有用吧。

,and just works.

手動點個贊

就是覺得未來就在眼前了~