S****f
发帖数: 30 | 1 That's what have been observed in the weak processes. Therefore, the
electroweak model which describes the weak interactions was built to be a
model where parity symmetry is totally broken. If you want to ask why parity
conservation is broken in nature, there may not be a consensus answer to it
. Some grand unified theories may answer this question. |
|
B*********h
发帖数: 800 | 2 ☆─────────────────────────────────────☆
majiangpai (Model的男人，消灭投机.客) 于 (Thu Mar 15 17:49:21 2007) 提到:
Ok, here comes another real put-call parity problem.
At today's market close: AGIX stock close at: 8.79
And its Apr. 7.5 Call quote (Bid: 4.40 Ask 4.70)
its Apr. 7.5 Put quote (Bid: 3.8 Ask 3.90)
The stock does not pay dividend.
According to the put-call parity:
CallPrice+Strike = PutPrice+SharePrice
Arbitrage opportunity:
Left side we have Buy action: 1 Call @ 4.70
Right side we have S |
|
p*******u
发帖数: 92 | 3 broad recovery for the dollar pushed the euro sharply below parity with the US
currency for the first time in over a week as US funds repatriated assets and
investors took profits on the single currency's sharp gains.
The euro fell to $0.9860 against the US currency, its lowest level since
Friday 12 July, before recovering to $0.9905. It closed at $1.0079 in New York
on Monday.
"US funds seem to be bringing money home and there's some talk of needing
dollars for margin calls, but the market look |
|
c********y
发帖数: 98 | 4 I was wondering if anyone here could enlighten me about the respective advanta
ges of using currency exchange rate and purchasing power parity in making inte
rnational comparisons.
China's per capita GDP is around $1000 by exchange rate, but over $4000 by PPP
. But this thing per se does not matter much. More importantly, by PPP calcula
tions it's China, rather than Japan, that is the world's second largest econom
y. Not sure if the ranking would still be the same if we use exchange rates.
Also, |
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b*****k
发帖数: 80 | 5 yes,it's a block code
the parity check matrix is very sparse,or said differently, low density.
Gallegar discovered this in 60s and people rediscover this code
in late 90s which shows performance(w/ 10^7 block length)
very close to shannan capacity.
This code and another popular codes--turbo codes use similiar
iterative decoding stragety. A new tool--factor graph
(or normal graph in Forney's vocabulary)
is also formulated to anaylize the behavior of those codes.
LDPC code has lower decoding compl |
|
g****y
发帖数: 4 | 6 有2个练习题我想不通道理：
1: Using your knowledge of Put-Call parity theorem,what would be the most
appropriate method of eliminating risk in the following position?
Short one future, long one call
(a)Buy call
(b)Sell call
(c)Sell put
(d)sell future.
答案是C,说The exsiting position is a sunthetic long put(这句话我不理解）,
therefore, sell a put to hedge the position.
2: An investor is long the underlying asset and owns a put option on the
same asset. Which of the fllowing strategies would eliminate the market risk
of t |
|
r**u
发帖数: 69 | 7 put-call parity is really basic and essential
S+P=C+K.
And you can roughly think of futures as spot in this case.
The answers you get are just the variations of the above formula. |
|
d********t
发帖数: 9628 | 8 risk parity很nb，好像一个中国人发明的，大家都在用。但是，跟dev没啥关系好像。 |
|
|
C****o
发帖数: 1549 | 10 【 以下文字转载自 Physics 讨论区 】
发信人: DonEinstein (Albert), 信区: Physics
标 题: 杨振宁先生给吴大猷先生谈论李政道先生的信函
发信站: BBS 未名空间站 (Mon Feb 27 14:50:30 2017, 美东)
大猷師︰
謝謝您寄下的《在台工作回憶》，是吾師三十年在台工作的總結，讀後感慨甚多。
一九六七年以來吾師在台不愉快的事，自書中多處可以看到。今日公諸于世也好。大公
無私，直言不諱的精神是會受到有識者的敬仰的。
關于馬仕俊師的剪報我是第一次看到。
多年來知道吾師極關懷政道與我一九六二年決裂的事，因為我嚴格遵守「君子交惡，不
出惡聲」的原則，始終沒有向吾師與吳太太談及詳情。今日簡要地談一下︰
I． 一九六二年以前與以後我一直不同任何人談李與我的關系，除了和我父母弟妹和兩
位家庭朋友以外。這是我的原則。政道則四處亂講，說我與他在粒子方面的工作主要是
他 帶領的，等等。我雖多次听到關于他這種胡說的謠言，並沒有改變自己的原則，直
到一九七 九年。那年夏天我偶然看到李一九七0年的文章（翻印在李《Selected
Papers》中）... 阅读全帖 |
|
发帖数: 1 | 11 大猷師︰
謝謝您寄下的《在台工作回憶》，是吾師三十年在台工作的總結，讀後感慨甚多。
一九六七年以來吾師在台不愉快的事，自書中多處可以看到。今日公諸于世也好。大公
無私，直言不諱的精神是會受到有識者的敬仰的。
關于馬仕俊師的剪報我是第一次看到。
多年來知道吾師極關懷政道與我一九六二年決裂的事，因為我嚴格遵守「君子交惡，不
出惡聲」的原則，始終沒有向吾師與吳太太談及詳情。今日簡要地談一下︰
I． 一九六二年以前與以後我一直不同任何人談李與我的關系，除了和我父母弟妹和兩
位家庭朋友以外。這是我的原則。政道則四處亂講，說我與他在粒子方面的工作主要是
他 帶領的，等等。我雖多次听到關于他這種胡說的謠言，並沒有改變自己的原則，直
到一九七 九年。那年夏天我偶然看到李一九七0年的文章（翻印在李《Selected
Papers》中），才了解到謠言並非全無根據，才了解到他背後怎樣在歪曲我和 他的關
系。震驚之余我才決定寫出真象，這是一九八三年我的《Selected Papers》第30頁足
注的背景。
II． 一九八三年以後我仍然避免談李和我的關系，可是政道卻繼續亂講。近年來他發
表了幾篇文章，包括︰ ... 阅读全帖 |
|
发帖数: 1 | 12 大猷師︰
謝謝您寄下的《在台工作回憶》，是吾師三十年在台工作的總結，讀後感慨甚多。
一九六七年以來吾師在台不愉快的事，自書中多處可以看到。今日公諸于世也好。大公
無私，直言不諱的精神是會受到有識者的敬仰的。
關于馬仕俊師的剪報我是第一次看到。
多年來知道吾師極關懷政道與我一九六二年決裂的事，因為我嚴格遵守「君子交惡，不
出惡聲」的原則，始終沒有向吾師與吳太太談及詳情。今日簡要地談一下︰
I． 一九六二年以前與以後我一直不同任何人談李與我的關系，除了和我父母弟妹和兩
位家庭朋友以外。這是我的原則。政道則四處亂講，說我與他在粒子方面的工作主要是
他 帶領的，等等。我雖多次听到關于他這種胡說的謠言，並沒有改變自己的原則，直
到一九七 九年。那年夏天我偶然看到李一九七0年的文章（翻印在李《Selected
Papers》中），才了解到謠言並非全無根據，才了解到他背後怎樣在歪曲我和 他的關
系。震驚之余我才決定寫出真象，這是一九八三年我的《Selected Papers》第30頁足
注的背景。
II． 一九八三年以後我仍然避免談李和我的關系，可是政道卻繼續亂講。近年來他發
表了幾篇文章，包括︰ ... 阅读全帖 |
|
发帖数: 1 | 13 https://www.zhihu.com/question/380469661
如题哈, 还没见报, 但是已经爆了
建议修改题目为“业绩大幅回撤”，而不是爆仓。
__________________________________________________
看过经典港剧《大时代》的朋友，可能记得刘青云饰演的方展博在股市的第一次成名之
作，是“火烧连环船”，大破陈万贤。（不禁再次感慨神剧）
桥水一直使用的Risk Parity策略，看起来无懈可击，但实际上和连环船一样，整体抗
风险能力很强，但是由于反复叠加杠杆，一旦敌方火力够猛，一艘船起火，那么整个舰
队都将付之一炬。
从目前看到的信息来看，负责点火的，貌似是沙特。周瑜打黄盖，愿打愿挨；沙俄闹沙
特，重挫原油。由于原油价格下跌，沙特需要资金维持国家财政，再加上美国疫情暴发
，股市看起来没那么好，就想起来从美国赎回资金，而由于达里奥的天才销售能力，沙
特有很多资金在桥水里面，也有很多钱在类似桥水的Risk Parity里面。
但是仅有沙特这个黄盖，是不会那么夸张的，因为缺一个东西，东风。但是疫情在美国
启动的时点，几乎和沙特点火时... 阅读全帖 |
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q*d
发帖数: 22178 | 14 你这个问题提的好,那篇炸药奖的论文关于实验部分的结构是这样的:
Question of parity conservation in β decay
Possible experimental tests of parity conservation in β decays
Question of parity conservation in meson and hyperon decays
Possible experimental tests of parity conservation in meson and hyperon
decays
其中那个meson和hyperon decay的,就是你们津津乐道的和Steinberger相关
实验.
最后证明parity violation的第一个实验是C.S.Wu的β decay,也是文中建议
第一个办法.另外两个组,Garwin和Telegdi组是第二个方案做的.
Steinberger这么重要,怎么就miss掉了parity violation这个实验的第二个方案呢?
TD同学对他还是留了一手? |
|
g****g
发帖数: 1828 | 15 What is direct CP violation?
By Davide Castelvecchi
Direct and indirect CP violation are two mechanisms that break the symmetry
between the behavior of matter and anti-matter. The BaBar experiment first
discovered indirect CP violation for B and anti-B (or B-bar) mesons in 2001.
BaBar’s new result is the first observation of direct CP violation for B/
anti-B mesons.
The BaBar Detector at SLAC. (Photo by Peter Ginter)
Historically, physicists believed that in a mirror image of the world all
laws... 阅读全帖 |
|
z********n
发帖数: 1729 | 16 Physicists said that, based on a review of new data, they are confident that
they have discovered a Higgs boson, a long-sought particle crucial to
explaining the universe.
Physicists say they are now confident they have discovered a long-sought
subatomic particle known as a Higgs boson. Gautum Naik reports.
.Earlier
Physicists Mine Cosmic Answers Deep Underground (7/29/2012)
Discovery May Help Tell Universe's Secrets (7/4/2012)
The Numbers Guy: How to Be Sure You've Found a Higgs Boson (7/6/2012... 阅读全帖 |
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f***y
发帖数: 4447 | 17 http://bbs.netbig.com/thread-2702025-1-2.html
一期9篇研究性文章，1/3是科大的，郭光灿组两篇，潘建伟组一篇
另外在news and views还有一篇点评潘建伟的工作
etters
Experimental investigation of the no-signalling principle in parity–time
symmetric theory using an open quantum system - pp642 - 646
Jian-Shun Tang, Yi-Tao Wang, Shang Yu, De-Yong He, Jin-Shi Xu, Bi-Heng Liu,
Geng Chen, Yong-Nan Sun, Kai Sun, Yong-Jian Han, Chuan-Feng Li & Guang-Can
Guo
doi:10.1038/nphoton.2016.144
The violation of the no-signalling principle — information can be
tr... 阅读全帖 |
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a*****1
发帖数: 314 | 18 请高手 解释一下。下面是什么意思啊？ 用C 写的？？？ 谢谢
3. Using a MACRO function to output the byte stream;
？？？ 什么意思啊？ 有知道的不？
9. Even parity function;
int getParity(unsigned int n)
{
int parity = 0;
while (n)
{
parity = !parity;
n = n & (n - 1);
}
return parity;
}
10. Extract the payload part from a packet;
这个也不明白？？ 有知道的吗？？
11. Rounding function; 四舍五入
int round(double number)
{
return (number >= 0) ? (int)(number + 0.5) : (int)(number - 0.5);
} |
|
a*****1
发帖数: 314 | 19 请高手 解释一下。下面是什么意思啊？ 用C 写的？？？
谢谢
3. Using a MACRO function to output the byte stream;
？？？ 什么意思啊？ 有知道的不？
9. Even parity function;
int getParity(unsigned int n)
{
int parity = 0;
while (n)
{
parity = !parity;
n = n & (n - 1);
}
return parity;
}
10. Extract the payload part from a packet;
这个也不明白？？ 有知道的吗？？
11. Rounding function; 四舍五入
int round(double number)
{
return (number >= 0) ? (int)(number + 0.5) : (int)(number - 0.5);
} |
|
b***i
发帖数: 3043 | 20 是这样，我们的串口数据是9位的，一串数据发出去，要求其中一个char的第9位置1，
其他都清零。
start, bit0, bit1, bit2, bit3, bit4, bit5, bit6, bit7, bit8, stop, start,
bit0, ....
而Linux是不支持9位串口的。幸好，串口有parity，我们可以在用户空间的软件发一个
char的时候，自己计算好parity，让它满足我们的要求。问题:
1. Linux串口驱动处理的时候，有没有驱动层的FIFO?因为我们需要每个char单独设
parity,如果有FIFO,这个信息就会遗漏。
2. 这个要往深层里说，我们其实有硬件的实现，是FPGA，我们可以在硬件里面建立
FIFO,包括parity，从而保证不丢失第9位。但是，这个没做过。另外，我们自己做串口
，是否需要给Linux 中断都不是很清楚。
3. 接收的时候，按照任意一种parity，那么一定会有错。能否保证所有数据都受到？
我们到不知在意接收到的第9位是什么，可以忽略第9位。
有能解答的吗？有思路也行 |
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D*a
发帖数: 6830 | 21 你自己看吧
1
00:00:01,200 --> 00:00:03,130
Hello, and welcome back to Animal
Behavior.
2
00:00:04,590 --> 00:00:06,189
When sexually reproducing animals
produce
3
00:00:06,189 --> 00:00:08,330
their offspring, they have a choice.
4
00:00:08,330 --> 00:00:13,030
They can produce either a son or a
daughter in any given reproductive event.
5
00:00:13,030 --> 00:00:15,730
In this lecture, we'll look at the
question of whether in certain
6
00:00:15,730 --> 00:00:17,330
circumstances it might pay parents t... 阅读全帖 |
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l****z
发帖数: 29846 | 22 No matter how well women are doing relative to men, it doesn’t matter. They
’re still the victims of discrimination — or so they think.
This, when women today earn more college degrees and advanced degrees than
men, and have lower rates of unemployment. How are the decks are still
stacked against them?
The new Pew Social Trends survey reports that “Millennial women . . . are
just as likely as older generations to believe that women face an uphill
climb in terms of being treated equally by societ... 阅读全帖 |
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t*****u
发帖数: 45 | 23 我曾在酒店做过收益管理系统，现在也自己创业做这一块，简单讲讲吧
业界有个术语叫做rate parity，国内叫做防止价格倒挂协议，要求就是各个OTA（例如
expedia，携程）的价格和官网价相同。任何一方不得违反，否则会有处罚。OTA违反，
酒店就不再提供房源；若酒店方违反，强势的OTA就会将酒店下架，或者将排名靠后。
这里rate parity其实是有价格垄断的背景的，对大的酒店或者OTA有利，而对小的就相
当吃亏了。OTA普遍的佣金在15%以上，有些超过20%。很多小酒店等于是被迫“卖身”
给OTA，让他们帮助销售客房。原因是他们没有有效的销售渠道。
原则上，有rate parity，应该所有的网站价格都相同。那么，为什么现实生活中有区
别呢？这个原因主要是由于不同的销售渠道造成的。
就以wholesaler（包房商）这个渠道为例吧，wholesaler量大，从酒店往往是7-9折可
以拿到客房。原则上这些房源必须按照package deal打包来卖，不能单独卖（裸卖）；
但是，很多包房商钻些空子，酒店的销售有入住率的压力，睁只眼闭只眼，也就让这部
分便宜房流通到了市面上。一般来说... 阅读全帖 |
|
t*****u
发帖数: 45 | 24 我曾在酒店做过收益管理系统，现在也自己创业做这一块，简单讲讲吧
业界有个术语叫做rate parity，国内叫做防止价格倒挂协议，要求就是各个OTA（例如
expedia，携程）的价格和官网价相同。任何一方不得违反，否则会有处罚。OTA违反，
酒店就不再提供房源；若酒店方违反，强势的OTA就会将酒店下架，或者将排名靠后。
这里rate parity其实是有价格垄断的背景的，对大的酒店或者OTA有利，而对小的就相
当吃亏了。OTA普遍的佣金在15%以上，有些超过20%。很多小酒店等于是被迫“卖身”
给OTA，让他们帮助销售客房。原因是他们没有有效的销售渠道。
原则上，有rate parity，应该所有的网站价格都相同。那么，为什么现实生活中有区
别呢？这个原因主要是由于不同的销售渠道造成的。
就以wholesaler（包房商）这个渠道为例吧，wholesaler量大，从酒店往往是7-9折可
以拿到客房。原则上这些房源必须按照package deal打包来卖，不能单独卖（裸卖）；
但是，很多包房商钻些空子，酒店的销售有入住率的压力，睁只眼闭只眼，也就让这部
分便宜房流通到了市面上。一般来说... 阅读全帖 |
|
r***i
发帖数: 913 | 25 First of all, the parity operation transforms a right-handed frame to a
left-handed frame. It is your right-hand rule that should also be modified
to left-hand rule when you talk about universe in the mirror.
Under parity operation (space inversion; flip signs in all three Cartesian
coordinates) the magnetic field stays the same. (E field flips direction).
Note that the vector potential A flips direction, and B = Curl A transforms
like an axial vector;
A mirror reflection (flip sign in one of th... 阅读全帖 |
|
|
p*********3
发帖数: 8525 | 27 《2010李传》第四章多处明示或暗示李是费米的博士生，而杨不是；《2004解谜》第14
问答中也如此说。这同样是只讲部分事实，以偏概全。
我确实不是费米的博士研究生，李是。可是我是费米的得意学生，而李不是。证明一：
费米在芝加哥的九年教过不少学生，其中只有我和他联名发表过理论物理文章[Phys.
Rev.76，1739(1949)]。证明二：1948年春费米为了弄懂Schwinger对重整化的工作（这
是当时最红的研究领域），每星期两、三个上午在他的办公室中讨论此工作。（见《
1983杨》6页）参加的除费米外，有两位教授：Teller与Wentzel，与五位研究生：Chew
、Goldberger、Rosenbluth、Steinberger与我，没有李（讨论了数周，结果由
Goldberger整理成49页的文件。但Schwinger的计算很难懂，我们的讨论完全失败）。
证明三：费米出差的时候，常请我代课，从没有请李（见《2004解谜》110页）。证明
四：费米于1954年11月28日因癌症逝世，享年53岁。他最后住医院期间我专程自美国东
岸飞往芝加哥去看他（《1983杨》307页）。... 阅读全帖 |
|
g******4
发帖数: 6339 | 28
-------------------
Purchasing power parity (PPP) is a component of some economic theories and
is a technique used to determine the relative value of different currencies.
The concept of purchasing power parity allows one to estimate what the
exchange rate between two currencies would have to be in order for the
exchange to be at par with the purchasing power of the two countries'
currencies. Using that PPP rate for hypothetical currency conversions, a
given amount of one currency thus has the ... 阅读全帖 |
|
c*****t
发帖数: 69 | 29 去了IDT onsite，这里给大家分享一下自己的经历。职位是ASIC Design Engineer。这
家公司以前是做memory起家的，现在也做一些视频传输，显示方面的ip。因为公司不大
，所以面试流程相对自由。住宿安排在了公司旁边的酒店，走路就能过去，很方便。
面试早上9点开始，先是一个印度的manager带着介绍了一下公司的办公环境，然后大概
讲了一下公司的情况。然后9点半开始正式面试。面试的一共四个人，是一起面试的。
面试一共有两个部分，先是让我介绍以前在学校做过的项目。感觉他们也不是很有兴趣
，但是还是让我讲了一个半小时。期间问了些问题，都是关于项目本身的，所以还比较
好回答。
第二部分是问一些技术问题，先是问了一个关于error correction code的。但是问法
比较奇怪：说有一个经理在办公室里放了4种颜色的球，一共12个，门外有12个员工。
经理依次扔出12个球，每扔出一个，让1个员工进来猜扔出的球是什么颜色，如果猜对
了，就算成功。进来的员工可以看到剩下的球是什么颜色，他不可以把这个信息告诉后
来的员工，但是可以告诉他们他猜测的何种球。问员工们采取什么策略... 阅读全帖 |
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D***h
发帖数: 183 | 30 bless, 慢慢习惯了就好了
去了IDT onsite，这里给大家分享一下自己的经历。职位是ASIC Design Engineer。这
家公司以前是做memory起家的，现在也做一些视频传输，显示方面的ip。因为公司不大
，所以面试流程相对自由。住宿安排在了公司旁边的酒店，走路就能过去，很方便。
面试早上9点开始，先是一个印度的manager带着介绍了一下公司的办公环境，然后大概
讲了一下公司的情况。然后9点半开始正式面试。面试的一共四个人，是一起面试的。
面试一共有两个部分，先是让我介绍以前在学校做过的项目。感觉他们也不是很有兴趣
，但是还是让我讲了一个半小时。期间问了些问题，都是关于项目本身的，所以还比较
好回答。
第二部分是问一些技术问题，先是问了一个关于error correction code的。但是问法
比较奇怪：说有一个经理在办公室里放了4种颜色的球，一共12个，门外有12个员工。
经理依次扔出12个球，每扔出一个，让1个员工进来猜扔出的球是什么颜色，如果猜对
了，就算成功。进来的员工可以看到剩下的球是什么颜色，他不可以把这个信息告诉后
来的员工，但是可以告诉他们他... 阅读全帖 |
|
c*********t
发帖数: 2921 | 31 它们是两个不同的问题。
求parity,可以用 XOR,5次操作，无论这个整数里1的个数是多少。
原理， xor整数的前半部分和后半部分，不会改变整体的parity.
因为1^1 = 0, 1^0 = 1, 0^0 =0
bool parity(unsigned int v)
{
v ^= v >> 16;
v ^= v >> 8;
v ^= v >> 4;
v ^= v >> 2;
v ^= v >> 1;
return v&0x1;
} |
|
u********e
发帖数: 4950 | 32 ☆─────────────────────────────────────☆
caoy (caoy) 于 (Thu Jun 9 00:14:19 2011, 美东) 提到:
我看了下昨天spy期权的收盘情况, spy收在128.4
Jul 15到期, strike=128的call收在2.5, put收在2.9
这个call的implied volatility是14%, put的iv是20%, 明显put高估
根据put-call parity等式: call+K/(1+r)=put + stock
所以就存在无风险套利:
short 128 put @2.9
buy 128 call @ 2.5, short stock @ 128.4
总共利润是 0.8 $ , 不管到期股价是多少
$0.8 / 128*12=9.3% 年化利润率
因为是无风险利润, 加杠杆!!!!
===========
这样套利空间就压缩了, 大概只有0.2, 只适合大资金搞了
call + K/(1+r) = Put + (stock-0.55)
☆─────────────────────... 阅读全帖 |
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d**y
发帖数: 18174 | 33 olympian可能得算outliers。如果只看ncaa div1：
Results/Findings.
For NCAA Div I: 65% come from the tallest 25%. 3% come from the
shortest 25%.
For NCAA Div I: The fastest 1% come from the tallest 5%(>74.25”
men, >68.55” for women).
For NCAA Div I: Taller swimming groups are faster on average than
smaller swimming groups.
For NCAA Div I: SP parity exists across all height groups.
The average height of motivational performance groups gets taller
as the performance... 阅读全帖 |
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l*****o
发帖数: 318 | 34 First of all you need to know what is "parity". It is a coordinate transform
ation so that x -> -x, that is, the coordinate system is flipped.The right-h
anded system becomes left-handed, like you look into a mirror.If you flip th
e coordinate system in the electromagnetic theory, you'll find the formula d
on't change. We say the parity is conserved in EM interaction.
You cannot distinguish the real world from the world in a mirror by looking
at EM interaction.
The first evidence of parity non-c |
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l**********1
发帖数: 5204 | 35 木桶原理: 一个木桶可以盛的水量由那个木桶上的最矮的那块木板确定的
AP/PI 最多发CNS 也不如Chien-Shiung-Wu 的一篇 Physical Review 对理论量子物理学的正面影响大
Wu, C.S., Ambler, E., Hayward, R.W., D.D. Hoppes, and Hudson, R.P.
Experimental test of parity conservation in beta decay (1957)
Physical Review, 105(4)
//ccreweb.org/documents/parity/parity.html
more try go to:
//acelebrationofwomen.org/?p=24738
//www.tumblr.com/tagged/chien-shiung-wu
//c250.columbia.edu/c250_celebrates/remarkable_columbians/chien-shiung_wu.html
//www.schrodingerskitten.co.uk/a... 阅读全帖 |
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w*******x
发帖数: 489 | 36 啊你是谁？ 怎么知道我是做lattice的？？
G parity我也不知道怎么解释有什么意义，还没仔细想过， 看看 wiki
http://en.wikipedia.org/wiki/G-parity
就是那样吧。
话说回来老板催我几次要我好好研究研究G parity in Lattice 了，因为这样做之后可
以使pi^0 的最低态带上动量pi/L, 就像
pi^+ （pi^- ）用antiperiodic boundary condition 一样。
你做TechniColor的？ |
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l******o
发帖数: 298 | 37 宇称： parity
对称： symmetry
吴健雄用 对称(symmetry)被破坏 去断定 宇称(parity) 也被破坏。
宇称(parity)不是说什么 (-1)的几次方吗？
对称(symmetry)就是说如果一个试验发生了，那么这个试验关于某个平面的对称的试验
也一定会发生，两次试验结果应该一样。
宇称 和 对称 是不是一回事？ |
|
m*********i
发帖数: 38 | 38 太误导大众了
乍一看
李政道可显得牛多了
李政道（1926年11月24日－），华人物理学家，主要的物理学贡献有李模型、高能重离
子物理、量子场论的非拓扑性孤立子和孤立子星以及破解粒子物理中的θ-τ之谜。
1957年，31岁时与杨振宁一起因弱作用下宇称不守恒的发现获得诺贝尔物理学奖，理论
由吴健雄的实验证实。李政道和杨振宁是首两位中华民国国籍[1]的华人诺贝尔奖得主。
杨振宁（英文名：Chen-Ning Franklin Yang，1922年10月1日－[1]）是一位華裔物理
学家。他與李政道提出了宇稱不守恆理論，并与他共同獲得了1957年諾貝爾物理學獎，
他們是最早的华人诺贝尔奖得主。
英文版：
Tsung-Dao Lee (T.D. Lee, Chinese: 李政道; pinyin: Lǐ Zhèngdào) (born Nove
mber 24, 1926) is a Chinese-born American physicist, well known for his work
on parity violation, the Lee Model, particle physi... 阅读全帖 |
|
l**********n
发帖数: 72 | 39 Contrary to what you said, I believed Yang contributed more in the parity
violation in weak interactions. And I also trusted Yang more than Lee. Here
are my reasons:
1) You can find their own description of the cooperation in parity violation
from Lee's book "30 years after Parity violation in weak interactions", which
is a collection of many papers to celebrate Lee's 60 year birthday. And you
can also find the corresponding articles in Yang's selection of papers. In
Lee's description, he stress |
|
c**i
发帖数: 6973 | 40 Martin Wolf, How China Could Yet Fail Like Japan. Financial Times, June 15,
2011
http://www.ft.com/cms/s/0/6247d8e2
-96b8-11e0-baca-00144feab49a.html
("If this pattern of growth [transferring household income to business,
especially state-owned, thereby from consumption to investment] is to
reverse, as the government wishes, the growth of investment must fall well
below that of GDP. This is what happened in Japan in the 1990s, with dire
results. * * * Much of the investment now undertaken would ... 阅读全帖 |
|
y**********7
发帖数: 769 | 41 的确票价不能只是通过'名义'(nominal)货币兑换率(exchange rate)来计算. 应该根据
PPP理论来确立. PPP ( purchasing power parity) 考虑了不同国家的相对生活费用和
实际购买力,反映了'真'(real)货币兑换率.
There can be marked differences between PPP and market exchange rates. For
example, the World Bank's World Development Indicators 2005 estimated that
in 2003, one United States dollar was equivalent to about 1.8 Chinese yuan
by purchasing power parity — considerably different from the nominal
exchange rate that put one dollar equal to 7.6 yuan.
因此,中国高铁的价格是大大超过了德国 |
|
s*******u
发帖数: 1855 | 42 I read some articles also. Below are my conclusions:
1) Yang is definitely a much better physicist than Lee. The violation of
parity law in weak interaction is Lee's topmost contribution, while it is at
most the 2nd greatest contribution from Yang. The gauge field theory
contribution from Yang is way more important than the parity violation work.
Many physics major believe Yang is among top 15 or top 20, if not top 10,
among all physicists in 20th century. Lee? Top 100?
2) Yang also should take ... 阅读全帖 |
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s*******w
发帖数: 2257 | 43 华夏文摘】林木：方励之学长点滴及其他
发表于 2015 年 06 月 09 日 由 baichuan
方励之学长（1936–2012）过世将及贰载，作文以纪念之。方励之是“北大物理百年”
的杰出代表，生前担任了ICRA（国际相对论天体物理中心）指导委员会主席，北大物理
百年来有几人担当过物理学国际学术机构的领头人？1956年从北大毕业的方励之夫妇是
“院系调整”后第一代青年学子，作为学生干部更是处处带头响应党的号召听党的话，
又红又专。方励之猝死前的办公桌上还摆放着下半年要来随他作研究的中国学生的资料
，至死不忘服务中国。方励之那一代人是最虔诚最热烈的爱国者！但是，国爱他们吗？
作为“六四”精神领袖，方励之夫妇在1990年6月25日无奈去国后，可怜再也没有踏上
故土，有国难投，他们被剥夺了回来的权利，故国不堪回首月明中。方励之已仙去，让
他魂兮归来吧！
方励之学长高我二个年级
方励之长我半岁（6个月零3天）却高我二个年级，16岁时他已读大学。“解放”前方励
之参加了共产党的外围组织“民主青年同盟”，后来，参加该组织者都享受到了“离休
”待遇。1954年我入学北京大学物理系时，方励之和李... 阅读全帖 |
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c***l
发帖数: 2395 | 44 这段也好玩
admiralsonasongbird 08:05 AM on 10/27/2010
219 Fans
The chinese are building their country while we are building Afghanistan and
Iraq.
ArtsyJane 08:10 AM on 10/27/2010
163 Fans
I don't think we're building anything in Afghanistan and Iraq.
HUFFPOST SUPER USER
Red Herring 10:12 AM on 10/27/2010
85 Fans
No I think he was confused I think he meant the government is trying to make
the USA INTO Afganistan and Iraq. Thats why the USA is letting everything
fall down around your ears. As soo... 阅读全帖 |
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w*******r
发帖数: 7276 | 45 World maps of GDP (PPP), 2010 International Monetary Fund
There are three lists of countries of the world sorted by their gross
domestic product (GDP) (the value of all final goods and services produced
within a nation in a given year). The GDP dollar estimates given on this
page are derived from purchasing power parity (PPP) calculations.
Using a PPP basis is arguably more useful when comparing generalized
differences in living standards on the whole between nations because PPP
takes into accou... 阅读全帖 |
|
l****u
发帖数: 3130 | 46 昨天，印度远程导弹"烈火-5"试射成功，印度藉此跻身洲际导弹俱乐部；然而印度媒体
的另一则报道同样让印度人感到兴奋。印度媒体昨天报道称，按照购买力平价法计算，
印度2011年的国内生产总值已经超越日本，成为继美国和中国之后的全球第三大经济体。
India overtakes Japan to become third-largest economy in purchasing power parity
DEVIKA BANERJI & RISHI SHAH, ET Bureau Apr 19, 2012, 07.11AM IST
Tags:World Bank|policy measures|Japan|INTERNATIONAL MONETARY FUND|Indian rupee|Gross Domestic Product|economic growth rate|Big Mac index
NEW DELHI: Its economy may be in the grips of a slowdown, its polity paralysed and markets moro... 阅读全帖 |
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N*****m
发帖数: 42603 | 47 PPP加PPT
a3统计局无敌
体。
parity
rupee|Gross Domestic Product|economic growth rate|Big Mac index
paralysed and markets morose, but all this hasn't prevented India from
overtaking Japan to become the world's third-largest economy in purchasing
power terms.
India's gross domestic product in purchasing power parity (PPP) terms stood
at $4.46 trillion in 2011, marginally higher than Japan's $4.44 trillion,
making it the third-biggest e |
|
k*********t
发帖数: 2999 | 48 太好了，三哥世界第一就更好了。呵呵
体。
parity
rupee|Gross Domestic Product|economic growth rate|Big Mac index
paralysed and markets morose, but all this hasn't prevented India from
overtaking Japan to become the world's third-largest economy in purchasing
power terms.
India's gross domestic product in purchasing power parity (PPP) terms stood
at $4.46 trillion in 2011, marginally higher than Japan's $4.44 trillion,
making it the third-biggest economy after the United States and China. |
|
c*****i
发帖数: 11737 | 49 阿三太需要一场败仗来清醒一下了
体。
parity
rupee|Gross Domestic Product|economic growth rate|Big Mac index
paralysed and markets morose, but all this hasn't prevented India from
overtaking Japan to become the world's third-largest economy in purchasing
power terms.
India's gross domestic product in purchasing power parity (PPP) terms stood
at $4.46 trillion in 2011, marginally higher than Japan's $4.44 trillion,
making it the third-biggest economy after the United States and China. |
|
l******r
发帖数: 18699 | 50 为什么印度这样agressive的国家没有选出一个类似希特勒的元首？
体。
parity
rupee|Gross Domestic Product|economic growth rate|Big Mac index
paralysed and markets morose, but all this hasn't prevented India from
overtaking Japan to become the world's third-largest economy in purchasing
power terms.
India's gross domestic product in purchasing power parity (PPP) terms stood
at $4.46 trillion in 2011, marginally higher than Japan's $4.44 trillion,
making it the third-biggest economy after the United States and China. |
|
