進度
第一週
內容
Welcome
Module 1. Introducing the building blocks of a quantum computer
Lecture 1 + Quiz 1: Introduction of the building blocks of a quantum computer
Lecture 2 + Quiz 2: Quantum materials
時間
2018/9/5 (三) - 2018/9/16 (日) 23:59
備註
本周為第一週課程，讓大家多幾天的時間摸索 edX 這個網站以及課程行進方式。我的目標是帶領各位成員完成課程，在規劃的時程內可以取得結業證書。為了瞭解各位的學習狀況，請大家紀錄每週的測驗 (quiz) 分數還有簡單的心得 (本週感想、疑問等形式不拘)。此外，我會整理 line 群組裡的討論重點貼在下方的課程討論內，若大家有任何想法也請在課程討論裡發表，與其他人一起集思廣益，最後請在9/4課程開始之後至
註冊並進入課程，謝謝。
課程討論
問題與看法:
藍暄 2018/8/12
課程討論
- Introducing the building blocks of a quantum computer:
- Current efforts are put into building a quantum accelerator, a computational add-on to the classical computers to exceed current performance.
- Heterogeneous multicore architecture entails a Field Programmable Gate Array, a Graphics Programming Unit and a quantum co-processor.
- The building blocks for a quantum computer are a quantum algorithm, a quantum language, a compiler, arithmetic, an instruction set, a micro-architecture, a quantum to classical conversion and a quantum chip.
- The "Quantum Algorithm" layer:
- The "Programming and Language" layer:
- The "Compiler" layer:
- The "Quantum Instruction Set" layer:
- The "Micro-architecture" layer:
- The "Quantum to Classic" layer:
- The "Quantum Chip" layer:
- 俗稱硬體 (Hardware)，含有量子位元及量子邏輯閘，是本門課探討的重點。
- 進行 non-deterministic computing，亦即每次運算結果可能都不一樣 (量子態因觀測而塌縮成某一投影態)
- 故量子電腦計算上異於傳統電腦，同樣的計算可能需要算 10-100 次以上，再從次數分布圖中重構原本之量子態。
- Quantum Materials
- Quantum materials provide the environment where qubits, the elemental unit of quantum information processing, are defined and live.
- Precision in material uniformity, chemical composition and electrical properties are crucial for the requirements of having both many qubits and long decoherence times.
- Chemical Vapour Deposition is an industrial process that uses high purity gases to make high quality materials, with desired physical and electronic properties.
- Transmission electron microscopy is a process to inspect the fabricated heterostructures with high resolution.
- Temperature, electric fields and magnetic fields are useful parameters to determine properties of quantum materials such as mobility and electron density.
問題與看法:
- 既然從Algorithm, Language, Instruction Set, 和Chip layer, 都已經是Quantum, 為什麼還需要"Quantum to Classic" layer: 將量子資訊與數位資訊做轉換這一層介於中間?
- A: 雖然前幾項會針對 quantum 進行設計，但本質上還是仰賴數位訊號的方式去進行溝通、編譯。看完影片後我的理解是除了運算本身是量子現象之外，從量測、量子態重建一直到轉譯成人類可讀的資訊都是靠傳統電腦的原理來完成。
- 先不管「進行 non-deterministic computing，亦即每次運算結果可能都不一樣 (量子態因觀測而塌縮成某一投影態)」這種量子電腦的本性, 若是「量子電腦計算上，同樣的計算可能需要算 10-100 次以上，再從次數分布圖中重構原本之量子態。」那麼他的計算效益就減低了10-100倍, 不是嗎?
- A: 是，因此也不少人在研究相關的議題，希望能盡可能減少取樣並提升重建的可靠度，symmetric informationally complete positive operator valued measure (SIC-POVM) 和 mutual unbiased (MU) 應該都是相關的方法。雖然重建會需要額外的資源，但是另一方面它預期可以解決指數型成長的計算難題，權衡之下應該還是有很大的優勢的。下表是一個每秒處理100萬次的傳統電腦解決不同形式的問題所需要的時間，可發現n^3 與 2^n 有非常顯著的差異，而後者應該是只能仰賴量子電腦才能解決了。
補充資料：
- Cooper pair: Electron-phonon interaction, creating electron pair behaves like bosons (integral spin), in the energy range of e-3 eV order, easily being destroyed by thermal vibration.
- The DiVincenzo criteria describes the essential properties that a quantum computer system should have:
- The system must be scalable with well defined qubits.
- The computer must have the ability to initialize the state of qubits.
- Qubits must have long decoherence times.
- The computer must be able to perform a universal set of quantum gates on the qubits.
- It should be possible to measure the qubits.
- The Majorana qubit: completely protected from the environment but hard to build.
- The NV center qubit: long coherence time, sensitive to magnetic field, slow in gate operation.
- The quantum dot qubit: short coherence and operation time, not easy to connected to others
沒有留言:
張貼留言