Comments on: 人择原理（5） http://limiao.net/33 惯性参照系 Wed, 17 Mar 2010 03:18:24 +0000 http://wordpress.org/?v=Weierstrass by: 博客李淼 » 存在 http://limiao.net/33#comment-12004 Fri, 31 Aug 2007 14:45:26 +0000 http://limiao.net/33#comment-12004 [...] 人择原理（1） 人择原理（2） 人择原理（3） 人择原理（4） 人择原理（5） [...] […] 人择原理（1） 人择原理（2） 人择原理（3） 人择原理（4） 人择原理（5） […]

]]> by: xiGang Blog » Blog Archive » 谷歌多重（转自桑林志） http://limiao.net/33#comment-1301 Thu, 20 Apr 2006 06:52:47 +0000 http://limiao.net/33#comment-1301 [...] 所以如果有 1 googol 颗谷子的话，我们所处的宇宙远远容不下它们。需要多个宇宙，不过超弦的 landscape 理论给了足够多的宇宙，我们可以从中选择个来存放丰收的谷子。这被称为谷择原理。 [...] […] 所以如果有 1 googol 颗谷子的话，我们所处的宇宙远远容不下它们。需要多个宇宙，不过超弦的 landscape 理论给了足够多的宇宙，我们可以从中选择个来存放丰收的谷子。这被称为谷择原理。 […]

]]> by: 桑林志 » 谷歌多重 http://limiao.net/33#comment-1282 Tue, 18 Apr 2006 21:29:57 +0000 http://limiao.net/33#comment-1282 [...] 所以如果有 1 googol 颗谷子的话，我们所处的宇宙远远容不下它们啊。需要多宇宙，不过超弦的landscape概念给了足够多的宇宙，可以从中选择个来存放丰收的谷子。这被称为谷择原理。 [...] […] 所以如果有 1 googol 颗谷子的话，我们所处的宇宙远远容不下它们啊。需要多宇宙，不过超弦的landscape概念给了足够多的宇宙，可以从中选择个来存放丰收的谷子。这被称为谷择原理。 […]

]]> by: sage http://limiao.net/33#comment-115 Sat, 31 Dec 2005 16:27:43 +0000 http://limiao.net/33#comment-115 I am not so sure that there is no way to prove the existence of many vacua. I think this is something one should work on in order to prove or disprove such a scenario. It is not a faith, rather a statement about nature. I am not so sure that there is no way to prove the existence of many vacua. I think this is something one should work on in order to prove or disprove such a scenario. It is not a faith, rather a statement about nature.

]]> by: 李淼 http://limiao.net/33#comment-113 Sat, 31 Dec 2005 09:40:36 +0000 http://limiao.net/33#comment-113 Sage: 1) There is certainly no proof that there are not many vacua in string theory. For the moment, I think the both sides of the debate lack strong evidence for their cases. 2) Simplicity and beauty is the best guidance when we don't have any experimental clues. again it is just soemthing like faith. 3) You are right, the anthropic idea and the cosmic landscape are not religious, but are just as meta-physical as any religion. I don't see any chance to prove the idea experimentally. This is a quite different situation than what Copernicus and Bruno presumed. Many anti-string people argue that string theory is not science and we can fight back with the argument that it can be falsified and we had a case. Now with the landscape even a string theorist will have to give in. Sage:

1) There is certainly no proof that there are not many vacua in string theory. For the moment, I think the both sides of the debate lack strong
evidence for their cases.

2) Simplicity and beauty is the best guidance when we don’t have any experimental clues. again it is just soemthing like faith.

3) You are right, the anthropic idea and the cosmic landscape are not religious, but are just as meta-physical as any religion. I don’t see any chance to prove the idea experimentally. This is a quite different situation than what Copernicus and Bruno presumed. Many anti-string people argue that string theory is not science and we can fight back with the argument that it can be falsified and we had a case. Now with the landscape even a string theorist will have to give in.

]]> by: sage http://limiao.net/33#comment-112 Sat, 31 Dec 2005 07:31:39 +0000 http://limiao.net/33#comment-112 I am not a big fan of landscape either. On the other hand, I have a few comments about your statement about the landscape. 1) I don't think the idea of landscape in general relies on the validity of a KKLT like construction. The real question is whether there are a large number of vacuum in nature. To me, it does not seem to be such a outrageous idea. Afterall, string theory (not only KKLT type of construction), does seem to have a lot of possible vacua. Of course, I undersatnd all the reservations people have, such as the ones you have against KKLT. On the other hand, I think the claim that string theory has an unique vacuum is at least as impossible. 2) I am not sure about the meaning of 'too complex to be true'. as you said, it is not scientific. 3) actually, multi-universe is the most anti-religious approach to the why we are here problem. we are here with absolutely no purpose, nothing is beautiful about our existence. We are here because of a freaking accident. There is no accident that the Church burnt Bruno, because he believe in multi-verse. I am not a big fan of landscape either. On the other hand, I have a few comments about your statement about the landscape.

1) I don’t think the idea of landscape in general relies on the validity of a KKLT like construction. The real question is whether there are a large number of vacuum in nature. To me, it does not seem to be such a outrageous idea. Afterall, string theory (not only KKLT type of construction), does seem to have a lot of possible vacua. Of course, I undersatnd all the reservations people have, such as the ones you have against KKLT. On the other hand, I think the claim that string theory has an unique vacuum is at least as impossible.

2) I am not sure about the meaning of ‘too complex to be true’. as you said, it is not scientific.

3) actually, multi-universe is the most anti-religious approach to the why we are here problem. we are here with absolutely no purpose, nothing is beautiful about our existence. We are here because of a freaking accident. There is no accident that the Church burnt Bruno, because he believe in multi-verse.

]]> by: 李淼 http://limiao.net/33#comment-49 Sat, 17 Dec 2005 04:39:35 +0000 http://limiao.net/33#comment-49 I suspect that the number will become infinite along the line of current strategy of kklt construction. I have no idea how to constrain the construction, I feel we need to develop tools. As the selection principle is concerned, it appears that the only availabe one is due to Banks and Johnson. I suspect that the number will become infinite along the line of current strategy of kklt construction.

I have no idea how to constrain the construction, I feel we need to develop tools.

As the selection principle is concerned, it appears that the only availabe one is due to Banks and Johnson.

]]> by: dan xie http://limiao.net/33#comment-48 Sat, 17 Dec 2005 04:19:45 +0000 http://limiao.net/33#comment-48 Do you mean that the number of vacua is infinite? There are a large number of vacuas in some string models, such as flux compactification. But in the present low energy effective theory frame, the number is very huge, and I donot know whether the number is finite, the counting is rather complicated. Although we have some constraints like supersymmetry, tadpole cancellation, etc, it doesnot reduces the number greatlty, I am wondering is there any other constaints ariseing from the string theory that will reduce the number of vacua, like the finitness of moduli volume, the rank of gauge group as Vafa states in his recent paper on swampland. Personally, I donot think there will be any selection principle to select the unique vacua if the present vacuas we consider are consistent. Do you have any opinion on the classical or quantum consistency of the flux vacua? Do you mean that the number of vacua is infinite? There are a large number of vacuas in some string models, such as flux compactification. But in the present low energy effective theory frame, the number is very huge, and I donot know whether the number is finite, the counting is rather complicated. Although we have some constraints like supersymmetry, tadpole cancellation, etc, it doesnot reduces the number greatlty, I am wondering is there any other constaints ariseing from the string theory that will reduce the number of vacua, like the finitness of moduli volume, the rank of gauge group as Vafa states in his recent paper on swampland.
Personally, I donot think there will be any selection principle to select the unique vacua if the present vacuas we consider are consistent. Do you have any opinion on the classical or quantum consistency of the flux vacua?

]]> by: 李淼 http://limiao.net/33#comment-47 Thu, 15 Dec 2005 05:32:43 +0000 http://limiao.net/33#comment-47 In quantum field theory, there is almost unique way to do renormalization, while in the case of landscape, we can hardly come up with a method using first principle-there is no first principle available so far. Thus people will resort to their imagination to invent a variety of regularizations. I imagine that figuring out a first principle to fix the problem of an infinite landscape is like working out some selection principle, which is great of course, but this is far beyond the scope of the current anthropic landscape philosophy. By the way, people already encountered a problem of infinity in the eternal inflation scenario. In quantum field theory, there is almost unique way to do renormalization, while in the case of landscape, we can hardly come up with a method using first principle-there is no first principle available so far. Thus people will resort to their imagination to invent a variety of regularizations.

I imagine that figuring out a first principle to fix the problem of an infinite landscape is like working out some selection principle, which is great of course, but this is far beyond the scope of the current anthropic landscape philosophy.

By the way, people already encountered a problem of infinity in the eternal inflation scenario.

]]> by: dan xie http://limiao.net/33#comment-46 Wed, 14 Dec 2005 19:19:00 +0000 http://limiao.net/33#comment-46 why you say that we can do whatever we want, if we invent certain regulization technic to overcome the infinity? we always do this in quantum field theory. why you say that we can do whatever we want, if we invent certain regulization technic to overcome the infinity? we always do this in quantum field theory.

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