& 周五植樹：栽一棵“海森貝格“樹

海森貝格的“觀察者效應”論點
http://en.wikipedia.org/wiki/Observer_effect

蜂鳥注：至今，此論點的中文的百科譯本尚未出現

Observer effect
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For the Star Trek: Enterprise episode, see Observer Effect.

The observer effect, or observer bias, has any of various context-specific meanings, some of which are related.
Contents
[hide]

* 1 Use in science
* 2 Use in information technology
* 3 Use in the social sciences
* 4 Observer bias
* 5 See also
* 6 References

[edit] Use in science

In science, the term observer effect refers to changes that the act of observing will make on the phenomenon being observed. For example, for us to "see" an electron, a photon must first interact with it, and this interaction will change the path of that electron. It is also theoretically possible for other, less direct means of measurement to affect the electron; even if the electron is simply put into a position where observing it is possible, without actual observation taking place, it will still (theoretically) alter its position.

In physics, a more mundane observer effect can be the result of instruments that by necessity alter the state of what they measure in some manner. For instance, in electronics, ammeters and voltmeters need to be connected to the circuit, and so by their very presence affect the current or the voltage they are measuring. Likewise, a standard mercury-in-glass thermometer must absorb some thermal energy to record a temperature, and therefore changes the temperature of the body which it is measuring.

A common lay misuse of the term refers to quantum mechanics, where, if the outcome of an event has not been observed, it exists in a state of 'superposition', which is akin to being in all possible states at once. In the famous thought experiment known as Schrödinger's cat the cat is supposedly neither alive nor dead until observed — until that time, the cat is both alive and dead (technically half-alive and half-dead in probability terms). However, most quantum physicists, in resolving Schrödinger's seeming paradox, now understand that the acts of 'observation' and 'measurement' must also be defined in quantum terms before the question makes sense. From this point of view, there is no 'observer effect', only one vastly entangled quantum system. A significant minority still find the equations point to an observer; Wheeler, who probably worked more deeply on this subject than any physicist thus far, devised a graphic in which the universe was represented by a "U" with an eye on one end, turned around and viewing itself, to describe his understanding.

The Heisenberg uncertainty principle is also frequently confused with the "observer effect". The uncertainty principle actually describes how precisely we may measure the position and momentum of a particle at the same time — if we increase the precision in measuring one quantity, we are forced to lose precision in measuring the other. Thus, the uncertainty principle deals with measurement, and not observation. The idea that the Uncertainty Principle is caused by disturbance (and hence by observation) is not considered to be valid by some, although it was extant in the early years of quantum mechanics, and is often repeated in popular treatments.

There is a related issue in quantum mechanics relating to whether systems have pre-existing — prior to measurement, that is — properties corresponding to all measurements that could possibly be made on them. The assumption that they do is often referred to as "realism" in the literature, although it has been argued that the word "realism" is being used in a more restricted sense than philosophical realism[1]. A recent experiment in the realm of quantum physics has been quoted as meaning that we have to "say goodbye" to realism, although the author of the paper states only that "we would [..] have to give up certain intuitive features of realism" [2] [3]. These experiments demonstrate a puzzling relationship between the act of measurement and the system being measured, but it is unclear if they require a conscious observer or not.

[edit] Use in information technology

In information technology, the observer effect is the potential impact of the act of observing a process output while the process is running. For example: if a process uses a log file to record its progress, the process could slow. Furthermore, the act of viewing the file while the process is running could cause an I/O error in the process, which could, in turn, cause it to stop.

Another example would be observing the performance of a CPU by running both the observed and observing programs on the same CPU, which will lead to inaccurate results because the observer program itself affects the CPU performance (modern, heavily cached and pipelined CPUs are particularly affected by this kind of observation).

Observing (or rather, debugging) a running program by modifying its source code (such as adding extra output or generating log files) or by running it in a debugger may sometimes cause certain bugs to diminish or change their behavior, creating extra difficulty for the person trying to isolate the bug (see Heisenbug).

[edit] Use in the social sciences

In the social sciences and general usage, the effect refers to how people change their behavior when aware of being watched (see Hawthorne effect). For instance, in the armed forces, an announced inspection is used to see how well soldiers can do when they put their minds to it, while a surprise inspection is used to see how well prepared they generally are.

In parapsychology, the observer effect refers to the situation of an experiment subject's expectations creating the experiment's results. The phrase was coined by two friends performing an experiment wherein they set up a number of volunteers who had to press the button when they felt they were being watched by the experimenters.[citation needed]

[edit] Observer bias

The related social-science term observer bias is error introduced into measurement when observers overemphasize behavior they expect to find and fail to notice behavior they do not expect. This is why medical trials are normally double-blind rather than single-blind. Observer bias can also be introduced because researchers see a behavior and interpret it according to what it means to them, whereas it may mean something else to the person showing the behavior. See subject-expectancy effect and observer-expectancy effect.

[edit] See also

* Anthropic bias
* Double-slit experiment
* Uncertainty principle

[edit] References

1. ^ Norsen, T. Against "Realism"
2. ^ Quantum physics says goodbye to reality
3. ^ An experimental test of non-local realism

* Observer Effect in the social sciences (Association for Qualitative Research)
* The observer effect (usage of the term in the computer industry)

Retrieved from "http://en.wikipedia.org/wiki/Observer_effect"

Categories: All articles with unsourced statements | Articles with unsourced statements since February 2007 | Philosophy of science | Types of scientific fallacy | Cognitive biases

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http://zh.wikipedia.org/wiki/%E7%BB%B4%E5%B0%94%E7%BA%B3%C2%B7%E6%B5%B7%E6%A3%AE%E8%B4%9D%E6%A0%BC
維爾納·海森貝格
維基百科，自由的百科全書

維爾納·海森貝格

出生
1901年12月5日
德國維爾茨堡
逝世 1976年2月1日
德國慕尼黑
研究領域 物理
著名事務 測不準原理、量子力學
國籍 德國
居住地 德國
研究機構 格丁根大學
哥本哈根大學
萊比錫大學
柏林大學
聖安德魯斯大學
慕尼黑大學
母校 慕尼黑大學
導師 阿諾爾德·佐默費爾德
學生 費利克斯·布洛赫
愛德華·特勒
獲獎 諾貝爾物理學獎（1932年）

維爾納·海森貝格（Werner Heisenberg，1901年12月5日－1976年2月1日），德國著名物理學家，雅利安人，量子力學的奠基人之一，“哥本哈根學派”代表性人物，因創立量子力學而獲1932年諾貝爾物理學獎。

他對物理學的主要貢獻是給出了量子力學的矩陣形式（矩陣力學），提出了“測不準原理”（又稱“不確定性原理”）和S矩陣理論等。他的《量子論的物理學基礎》是量子力學領域的一部經典著作。
目錄
[隱藏]

* 1 生平
* 2 研究
* 3 榮譽
* 4 參考資料

[編輯] 生平

維爾納·海森貝格1901年12月5日出生於德國維爾茨堡，1920年從慕尼黑的一所中學畢業後，在慕尼黑大學學習物理學，師從阿諾爾德·佐默費爾德（Arnold Sommerfeld）等，1922年冬天轉去格丁根大學，師從馬克斯·玻恩（1954年諾貝爾物理學獎）、詹姆斯·夫蘭克（1925年諾貝爾物理學獎）和大衛·希爾伯特。1923年他在慕尼黑大學獲得博士學位，並去格丁根大學擔任玻恩的助手，1924年獲得大學任教資格。

1924年至1925年，他在哥本哈根大學工作，與尼爾斯·玻爾（1922年諾貝爾物理學獎）共事，1925年夏天回到格丁根。1926年又前往哥本哈根大學教授理論物理學，1927年，年僅26歲的海森貝格被任命為萊比錫大學的教授。1929年，他又前往美國、日本和印度巡回講學。1941年成為柏林大學的物理學教授和物理研究所主任。

第二次世界大戰結束後，他和其他德國物理學家作為囚犯，被美國軍隊送往英國。1946年重返德國後，他和他的同事們重建了格丁根物理研究所，該研究所在1948年改名為馬克斯-普朗克物理學研究所。1948年他在英國劍橋講學數月，1950年和1954年又應邀前往美國講學，1955年冬天他在蘇格蘭的聖安德魯斯大學教書，這些課程後來出版成書。1955年作為馬克斯-普朗克物理學研究所的主任，與研究所一起遷往慕尼黑，1958年成為慕尼黑大學的物理學教授，他的研究所被改名為“馬克斯-普朗克物理學和天體物理學研究所”（現為馬克斯-普朗克天體物理學研究所）。

海森貝格愛好古典音樂，是個出色的鋼琴手，1937年與伊麗莎白·舒馬赫（Elisabeth Schumacher）結婚，生有7個孩子，居住在慕尼黑。海森貝格逝世於1976年2月1日。

[編輯] 研究

海森貝格的名字一直都和他的量子力學理論聯係在一起，這一理論發表時他年僅23歲，他也因為提出這一理論及其應用（尤其是氫同位素的發現），獲得了1932年的諾貝爾物理學獎。

海森貝格提出的新理論，是完全基於對原子輻射的觀察，他認為，在某一個給定的時間點，一個電子所處的位置是無法確定的，也無法跟蹤它的軌跡，所以玻爾假定的電子軌道並不存在；諸如位置、速度等力學量，無法用通常的數字來描述，但可以用抽象的數學結構即矩陣來表達，海森貝格用矩陣形式給出了他的新理論（矩陣力學）。

＊＊＊　此後，海森貝格又提出了著名的“不確定性原理”（又稱“海森貝格測不準原理”），在一個量子力學係統中，一個運動粒子的位置和它的動量不可被同時確定，位置的不確定性Δx和動量的不確定性Δp是不可避免的，它們的乘積不小於h / 4π（h為普朗克常數），這些誤差對於人類來說雖然是微小的，但是在原子研究中並不能被忽略。＊＊＊

在萊比錫期間，海森貝格為原子核物理學做出了重要貢獻，為基本粒子理論引入了內部對稱量子數（1932年，1933年），發展了一種鐵磁性理論（1928年），和沃爾夫岡·泡利對量子場論進行了開創性研究工作。海森貝格和John Archibald Wheeler同為S矩陣（1942年，1944年）之父，他很早就研究了量子場論的基本長度模型（1938年）。1940年代，他還研究了宇宙射線及其產生的離子碎片，導致不久後在英國發現了第一個介子。

1957年起，海森貝格的研究興趣轉向了等離子體物理和高熱原子核反應問題，並與日內瓦國際原子物理研究所緊密合作，他擔任該研究所的科學政策委員會主席，並一直是該委員會的成員。在他於1953年成為洪堡基金會主席後，為基金會做了很多促進工作，他邀請各國科學家來德國，並協助他們在德國開展研究工作。

1953年起，他的理論工作偏向基本粒子的統一場理論，這對於他來說，是理解基本粒子物理學的關鍵。

[編輯] 榮譽

除了獲得馬克斯·普朗克獎章、德國聯邦十字勳章等獎章，諾貝爾物理學獎等獎項外，海森貝格還被布魯塞爾大學、卡爾斯魯厄大學和布達佩斯大學授予榮譽博士頭銜。他是倫敦皇家學會的會員，英國功績勳章騎士勳章，他還是格丁根、巴伐利亞、薩克森、普魯士、瑞典、羅馬尼亞、挪威、西班牙、荷蘭、羅馬、美國等眾多科學學會的成員，德國科學院和意大利科學院的院士。1953年成為洪堡基金會的主席。

[編輯] 參考資料

* Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965.
* Werner Heisenberg - Biography. The Nobel Foundation. （諾貝爾官方網站關於維爾納·海森貝格簡介）
* Ivan Todorov: Werner Heisenberg. Institut für Theoretische Physik, Universität Göttingen. Göttingen, Germany.