Subrahmanyan Chandrasekhar錢德拉塞卡1910~95 – 。艾薩克·牛頓。The double slit experiment was first performed by Thomas Young in 1801, as a demonstration of the wave nature of light.

雙縫實驗由 Thomas Young 於 1801 年首次進行，以證明光的波動性。他使用相干光源，例如陽光或蠟燭，並將其穿過卡片上的狹窄縫隙。然後，他將另一張帶有兩個平行狹縫的卡片靠近第一張卡片，並觀察第二張卡片後面的螢幕上的光圖案。他預計會在螢幕上看到兩個亮點，對應於兩條狹縫，但他看到的是一系列明暗條紋，稱為干 涉圖案。這意味著穿過兩個狹縫的光波會互相干擾，產生相長干涉和相消干涉區域。這證明光不是由粒子構成，正如艾薩克·牛頓所提出的那樣，而是由波構成的，正如克里斯蒂安·惠更斯所提出的那樣。 然而，隨著20世紀初量子力學的發展，人們發現光也可以表現得像粒子，稱為光子。 1905 年，阿爾伯特·愛因斯坦 (Albert Einstein) 解釋了光電效應，他假設光是由離散的能量包組成，這些能量可以將電子從金屬中擊出。 1924年，路易斯·德布羅意提出物質也可能具有波動性，並推導出任何粒子的波長和動量之間的關係。 1927 年，克林頓·戴維森(Clinton Davisson) 和萊斯特·傑默(Lester Germer) 以及喬治·湯姆森(George Thomson) 和亞歷山大·里德(Alexander Reid) 獨立證實了這一假設，證明電子在被晶體散射時可以產生干涉圖案。後來，人們發現原子和分子也可以表現出波粒二象性。 然後用單光子或電子重複雙縫實驗，一次一個。令人驚訝的是，即使一次只有一個粒子通過狹縫，經過多次重複後，螢幕上仍然出現干涉圖案。這意味著每個粒子都會以某種方式乾擾自身，就好像它同時穿過兩個狹縫一樣。然而，如果在狹縫處放置偵測器來觀察每個粒子通過哪個狹縫，干涉圖案就會消失。這表明測量行為會影響實驗的結果，而粒子的行為取決於它是否被觀察到。這種現象稱為量子疊加和坍縮，它意味著量子系統在被測量之前處於不確定狀態。 這個實驗對於我們理解現實和觀察的本質具有深遠的影響。它挑戰了我們的經典直覺，迫使我們接受現實在量子層面上不是確定性的而是機率性的。

The double slit experiment was first performed by Thomas Young in 1801, as a demonstration of the wave nature of light. He used a coherent light source, such as sunlight or a candle, and passed it through a narrow slit in a card. Then he placed another card with two parallel slits close to the first one, and observed the light pattern on a screen behind the second card. He expected to see two bright spots on the screen, corresponding to the two slits, but instead he saw a series of bright and dark fringes, called an interference pattern. This meant that the light waves passing through the two slits interfered with each other, creating regions of constructive and destructive interference. This was evidence that light was not made of particles, as Isaac Newton had proposed, but of waves, as Christiaan Huygens had suggested.

However, with the development of quantum mechanics in the early 20th century, it was discovered that light could also behave like particles, called photons. In 1905, Albert Einstein explained the photoelectric effect by assuming that light was composed of discrete packets of energy that could knock electrons out of metals. In 1924, Louis de Broglie proposed that matter could also have wave properties, and derived a relation between the wavelength and momentum of any particle. In 1927, Clinton Davisson and Lester Germer, and independently George Thomson and Alexander Reid, confirmed this hypothesis by showing that electrons could produce interference patterns when scattered by crystals. Later, it was shown that atoms and molecules could also exhibit wave-particle duality.

The double slit experiment was then repeated with single photons or electrons, one at a time. Surprisingly, even when only one particle was sent through the slits at a time, an interference pattern still emerged on the screen after many repetitions. This meant that each particle somehow interfered with itself, as if it went through both slits at once. However, if detectors were placed at the slits to observe which slit each particle passed through, the interference pattern disappeared. This showed that the act of measurement affected the outcome of the experiment, and that the particle's behavior depended on whether it was observed or not. This phenomenon is known as quantum superposition and collapse, and it implies that quantum systems exist in a state of uncertainty until they are measured.

The experiment has profound implications for our understanding of reality and the nature of observation. It challenges our classical intuition and forces us to accept that reality is not deterministic but probabilistic at the quantum level.

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382 年前的這一天，艾薩克·牛頓爵士於 1642 年出生（按照儒略曆）。 英國數學家、物理學家、天文學家、神學家和作家，他解開了運動定律和萬有引力定律，被公認為有史以來最有影響力的科學家之一。 艾薩克·牛頓爵士每週工作 7 天，每天 18 小時。他已經放棄了自己的個人生活，他可能從來沒有任何結婚或建立家庭的意圖。他想將一生奉獻給科學工作和對數學的追求，他也做到了。 艾薩克·牛頓因童年創傷而患有嚴重的精神問題，並透過自我隔離來應對，從而導致了他顯著的科學突破。 歷史學家和傳記作家確實注意到牛頓表現出各種心理疾病的跡象，包括可能的雙相情感障礙、憂鬱症以及與我們今天診斷為自閉症甚至精神分裂症一致的特徵。 牛頓的童年經歷了嚴重的創傷。他的父親在他出生前就去世了，他的母親在他很小的時候就改嫁了，留下他由祖母撫養長大。早期與母親的分離以及隨後與繼父的關係被認為是導致他後來的性格特徵和心理健康問題的因素。他的孤立傾向、對工作的高度關注以及可能被描述為瘋狂生產力的情況都有據可查。 牛頓在劍橋和後來在倫敦的工作環境給了他很大的自主權，這可能會被解釋為孤立。 他的同事和同時代人確實認識到他的天才，並經常給他工作空間，也許是出於對他獨特習慣和氣質的尊重或理解。

On this day , 382 years ago Sir Isaac Newton, was born (as per Julian calendar) in 1642.

An English mathematician, physicist, astronomer, theologian, and author whose mind unlocked the laws of motion and universal gravitation, and is recognised as one of the most influential scientists of all time.

Sir Isaac Newton worked 7 days a week, 18 hours a day. He had given up his personal life, he probably never had any intention of getting married or raising a family. He wanted to devote all his life to the works of science and the pursuit of mathematics and so he did.

Isaac Newton had severe mental problems due to childhood trauma and coped by isolating himself, leading to his notable scientific breakthroughs.

Historians and biographers have indeed noted that Newton exhibited signs of various psychological conditions, including possible bipolar disorder, depression, and traits consistent with what we might today diagnose as autism or even schizophrenia.

Newton's childhood was marked by significant trauma; his father died before he was born, and his mother remarried when he was very young, leaving him to be raised by his grandmother. This early separation from his mother and the subsequent relationship with his stepfather have been suggested as contributing factors to his later personality traits and mental health issues. His tendency towards isolation, intense focus on his work, and episodes of what might be described as manic productivity are well-documented.

Newton's work environment at Cambridge and later in London allowed him significant autonomy, which might be interpreted as isolation.

His colleagues and contemporaries did recognize his genius and often gave him space to work, perhaps out of respect or understanding of his peculiar habits and temperament.

《莎士比亞、牛頓和貝多芬──不同的創造模式》（ Truth and Beauty－ Aesthetics and Motivations in Science by S. Chandrasekhar）楊建鄴和王曉民譯，長沙：湖南科技出版社， 1996

　　日子飛逝，距作者（中譯名錢德拉塞卡）仙逝（ 1995年 8月21 日）已三年多了。猶記得三年多前在The Economist 看到作者訃聞，心中哀嘆一位偉大而獨特的科學家去世。特為此文致敬。

　　這本包含七篇擲地有聲的演講──「他們反應我對於科學研究的動機和科學創造模式的一般觀點。」「每篇都作過精心準備，在內容及細節上也做過認真的考慮。」這本書遠比一般的「科普」更深入、更博通。可稱為作者瀝血「明志」的作品，筆鋒中充滿智慧及情感。

　　作者指導了近半打的諾貝爾學生後，自己才在 1982年獲得該獎。作者畢生學問最特別的是，研究主題好幾次變換過。不過，每次都能「善入善出」，必有一番建樹。

作者不求驚天動地的突破，但求知識，不計名利。（在量子力學草創的黃金時代，即使第二流的人，也可以做出第一流的成果，而能在物理學上終身有成的人則甚少。）讀者可從本書附錄＜尋求秩序──錢德拉塞卡對黑洞、藍天和科學創造的思考＞中，大體了解斯人斯事。

　　作者有心逐字精讀莎士比亞全集，因為他以為唯有如此，才可以從全系統、全人生之歷練，來了解莎士比亞的成長、成熟、精進、造化。貝多芬在四十七歲時對一位朋友說：「現在我知道怎麼作曲了。」作者堅信，絕不會有位年滿四十七歲的科學家會如此說。因為科學家或因早慧（了了）而產生傲慢心，或如達爾文般，因長期習慣思考數據、推論後，反而對於詩歌等覺得索然無味。注意，作者只是從「抽象的意義」來討論這個問題。作者心儀十九世紀物理學家瑞利（ Reileigh）的長達五十年的研究生涯，只研究自己了解的，而又不與年輕人過意不去，就不會變成科學老怪人。

　　作者以為雪萊的《為詩辯護》，乃是英國文學史中最動人的文獻之一：

　「科學已經擴大了人們統轄外在世界王國的範圍，但是，由於缺少詩的才能，這些科學的研究，反而按比例地限制內在世界的領域；而且人既然已經馴服自然力，但是人自身卻依然只是一奴隸。

　　 ……

　　詩是最幸福最善良的心靈中最善良的瞬間的紀錄。

　　詩，可以使世間至善至美的一切永垂不朽； …

　　真的，詩是神聖的東西。它自己就是知識的圓心，又是它的週邊；它包含一切科學，一切科學也必須溯源到它。它同時是一切其它思想體系的根和花朵。

　　 …詩人，是未被世界公認的立法者。」

很有點新資料。由於只看過中文本Chandrasekhar, S. (1975). Shakespeare, Newton, and Beethoven: Or, Patterns of Creativity. University of Chicago. 然而知道他晚年立志讀完莎士比亞全集，沒達心願。他可能是典型的印度菁英。學生們都得諾貝爾，才輪到他，而且有點挖努似的：Chandrasekhar was awarded the Nobel Prize in Physics in 1983 for his studies on the physical processes important to the structure and evolution of stars. Chandrasekhar accepted this honor, but was upset the citation mentioned only his earliest work, seeing it as a denigration of a lifetime's achievement.


Subrahmanyan Chandrasekhar FRS (pronunciation) (19 October 1910 – 21 August 1995)^[3] was an Indian-American astrophysicist who spent his professional life in the United States.^[4] He was awarded the 1983 Nobel Prize for Physics with William A. Fowler for "...theoretical studies of the physical processes of importance to the structure and evolution of the stars". His mathematical treatment of stellar evolution yielded many of the current theoretical models of the later evolutionary stages of massive stars and black holes.^[5][6] The Chandrasekhar limit is named after him.

Ben Chen

Chandra小傳，只有薄薄的12頁，美金$1.05

左圖為是一張他別有感悟的攝影作品，特別找原作者要來放在辦公室內。

二十世紀最傑出的物理學家之一

一般對一個偉大的學者有很多稱讚的方式譬如說：桃李滿天下，開拓了一個全新的學術領域，這些Chandra 都當之無愧。

但我覺得最特別的是：Hans Bethe的說法：

Chandra was also the greatest master of the English language that I know”. — Hans Bethe, a Nobel Laureate and a Professor of Physics Emeritus at Cornell.