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我们最近在写一个可能很重要的文章！！！
根据现在黑洞微扰的理论发现，黑洞不吸收spin1/2，和spin1的粒子。但是，吸收spin0和spin2的粒子。我们因此猜想，量子黑洞的角动量只能取整数。这个就解释了为什么黑洞不吸收spin1/2，因为角动量要守恒。我们假设黑洞的内禀宇称是正的，这样就解释了为什么spin1的粒子不被吸收，当然这里假设了引力相互作用的宇称守恒。
大家有什么comment呀。
我无知到了只懂相对论了。
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i will love you till the null infinity.
| 发表时间：2005-07-10, 08:36:28 |
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sage
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Re: 我们最近在写一个可能很重要的文章！！！
not clear to me.
why blackhole cannot absorb spin 1/2 particle?
QCD conserve parity. however, it has spin-1 particle, the gluon.
| 发表时间：2005-07-10, 08:49:45 |
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卢昌海
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Re: 我们最近在写一个可能很重要的文章！！！
:: 黑洞不吸收spin1/2，和spin1的粒子
这话太笼统，给个文献吧。黑洞（假定不是 extremal blackhole）难道不会吸收单个电子吗？
宠辱不惊，看庭前花开花落
去留无意，望天空云卷云舒
| 发表时间：2005-07-10, 09:01:22 |
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轩轩
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Re: 我们最近在写一个可能很重要的文章！！！
这是来自最近黑洞的准正则震荡（quasi normal mode ）所得到的结果，现在这里类似与研究氢原子光谱的阶段。说的详细一点，黑洞实质不吸收单光子，这反过来说就是黑洞不辐射单光子，这有点类似与\pi介子的衰变，所以我们猜测黑洞的 Parity为正。
Sage兄可以把量子黑洞当作一个基本粒子。
我无知到了只懂相对论了。
http://zhangxuanzhong.blog.edu.cn/
《相对论通俗演义》
i will love you till the null infinity.
| 发表时间：2005-07-10, 09:05:42 |
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轩轩
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Re: 我们最近在写一个可能很重要的文章！！！
hep-th/0506214 [abs, ps, pdf, other] :
Title: Selection Rules for Black-Hole Quantum Transitions
Authors: Shahar Hod, Uri Keshet
Comments: 4 pages, 2 figures
文章很物理的感觉，可能昌海兄，Sage兄等看完对我们的想法和文章会有建设性的批评。：）这类似于量子力学诞生的时候………………我们要做量子黑洞，然后达到量子引力的目的。呵呵
我无知到了只懂相对论了。
http://zhangxuanzhong.blog.edu.cn/
《相对论通俗演义》
i will love you till the null infinity.
| 发表时间：2005-07-10, 09:11:09 |
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sage
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Re: 我们最近在写一个可能很重要的文章！！！
coupe of questions
1) in hep-ph/0506214, Eq. 3. this is apparent a sick solution for large n as the imaginary part blows up. what is the interpretation of this fact?
2) what do we know about the small n, non-asymptotic region? this is more interesting quantum mechanically.
3) it does not seem to me such a big deal that perturbative analysis in the large n regime produce a result which is more or less agree with thermal dynamics argument. you are equivalently doing perturbations in a semiclassical regime anyway by taking large n.
4) the equation one uses to solve for the quasi-normal modes, equationn 5 in gr-qc/9812002. I think it only applies for the asyptotic regions since it seems to treat the balckhole background as a classical potential. if so, the modes will carry very little information of the small n, small r* cases.
5) I think it seems that a huge leap of faith is necessary to consider something we obtain in the asymptotic regime to apply to all eigenstates and draw conclusions from it, such as selection rules. Using hydrogen atom as an example, looking at the asyptotic regime, we will conclude energy levels are evenly spaced. however, it is completely different for the small n levels, which are more close to 'true' quantum mechanical limit.
| 发表时间：2005-07-10, 19:04:12 |
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卢昌海
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Re: 我们最近在写一个可能很重要的文章！！！
我也提供几点看法供参考：
1. 黑洞发射与吸收粒子是两类非常不同的过程。发射过程主要由量子效应主宰，而吸收过程基本上是经典过程。hep-th/0506214 很小心地把结论限制在发射过程中，也就是说它的结论是球对称黑洞不能发射费米子，而没有宣称不能吸收费米子。事实上，我看不出有任何理由认为球对称黑洞不能吸收费米子（Schwarzchild 黑洞显然应该可以吸收单个电子 - 这是经典广义相对论可以适用的过程）。
2. “量子黑洞的角动量只能取整数”是比“量子黑洞不能发射费米子”更强的结果，因为它不仅禁止黑洞发射费米子，也禁止其吸收费米子，而后者 - 如上所述 - 我认为是不成立的。
3. hep-th/0506214 把计算限制在球对称黑洞中，似乎有先天的局限性，因为一个球对称黑洞发射费米子（如果可以发射的话）后应当变成非球对称，而把整个计算限制在球对称条件下本身就已经排除了发射费米子的可能性。
宠辱不惊，看庭前花开花落
去留无意，望天空云卷云舒
| 发表时间：2005-07-10, 20:38:55 |
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HPC
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Re: 我们最近在写一个可能很重要的文章！！！
Thanks Sage for criticisms. Here are some responses:
For large imaginary part, we think the quasinormal modes will be absorbed by black holes with a small interval of time, which corresponds to quantum transition of quantum black holes, since it is generally believed that quantum transition almost takes no time.
For small n, there is much work. In a sence, it is easier to treat from the viewpoint of technique.
For black hole, we perhaps need open mind. I do not think that black hole has the same picture as atom. Here we need some new idea and insight. I think Hod's correspondence principle is a good idea, which may shed light on our attempts to any kind of quantum black hole, even quantum gravity.
I prefer Hod's correspondence principle to Borh's.
I do not think I can give some replies to your other questions, which are beyond me.:)
Faith, Fashion and Fancy.
Welcome to 我的域名：http://hongbaozhang.blog.edu.cn
| 发表时间：2005-07-10, 20:52:15 |
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sage
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Re: 我们最近在写一个可能很重要的文章！！！
>For large imaginary part, we think the quasinormal modes will be absorbed by black holes with a >small interval of time, which corresponds to quantum transition of quantum black holes, since it is >generally believed that quantum transition almost takes no time.
============================================================================
the imaginary part of the \omega is not related to the time for quantum transition, it relates to life-time of a mode, i.e., how long one has to wait before it decays. if it is related to time for quantum transition , every particle in the world will have a inifinitely large imaginary part in their energy.
Now, the question is, how do I understand the width of quasi-normal mode n is proportional to n, or why its lifetime is proportional to 1/n.
>For small n, there is much work. In a sence, it is easier to treat from the viewpoint of technique.
it will be more important to study small n before conjecturing some selection principle. However, I suspect the method that paper use breaks down for small n. it is basically a semiclassical approximation and therefore should not be applicable for when the quantum effect is large.
>Here we need some new idea and insight. I think Hod's correspondence principle is a good idea, >which may shed light on our attempts to any kind of quantum black hole, even quantum gravity.
>I prefer Hod's correspondence principle to Borh's.
well, it is Bohr's principle.
I think the semiclassical result here is more or less on the same footing with the result from quantum field theory in a classical blackhole background. it should not carry too much information about the quantum gravity.
| 发表时间：2005-07-10, 21:08:28 |
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Re: 我们最近在写一个可能很重要的文章！！！
回昌海兄
谢谢昌海兄的有意思的评论，以下是我的一些看法，供讨论。：）
计算限制在球对称黑洞中，的确有先天的局限性。但是做黑洞物理的人一到转动黑洞头就疼。不过现在在这方面已经有明显的进展了。可是球对称不足以枪毙掉不发射Fermion.原因是我们发现球对称发射角动量不为零引力子，标量粒子。
经典黑洞的确什么东西都吃，却不会向外发射什么玩意儿。但是现在我们在量子的层次上谈黑洞，而如果我们相信Borh's correspondence principle, 那么highly-damped Quasinormal Modes本身就已经走到了量子区域。他不是什么东西都吃就似乎可以理解了吧。特别的，我觉得根据highly-damped Quasinormal Modes，直接得到的结果应该是吸收而不是辐射。原因是边界条件是进入黑洞。
从某种意义上来说，再量子的层次上来说，吸收和发射我认为是可逆的。但这并不能说明整数角动量的结果不比选择定则强，因为也许有一种动力学的机制导致了选择定则，而不是我们猜测的运动学的解释。
Faith, Fashion and Fancy.
Welcome to 我的域名：http://hongbaozhang.blog.edu.cn
| 发表时间：2005-07-10, 21:11:23 |
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Re: 我们最近在写一个可能很重要的文章！！！
to Sage:
I must admit that it is related to the life time of a mode. Highly damped mode corresponds to small life time. But for QNM of black hole, we want to where the mode decays. I think the answer is that it decays into black hole or go into the infinity due to the physical boundary condition.
for small imaginary part, the method by Hod may break down, but there are many other papers on this issue.
imaginary part may have some thermal meaning, which may be right, but beyond me.:)
Quantum mechanics or QFT in curved spacetime has show S=A/4.
Do you think it is related to some effects on quantum gravity?
Faith, Fashion and Fancy.
Welcome to 我的域名：http://hongbaozhang.blog.edu.cn
| 发表时间：2005-07-10, 21:26:35 |
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卢昌海
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Re: 我们最近在写一个可能很重要的文章！！！
I will be really surprised if a Schwarzchild black hole can NOT absorb an electron. Especially when the black hole is a large one for which quantum effects are extremely small. There is no reason classical general relativity should fail in this case (of course, electron is a quantum object, but that's not the condition for quantum gravity to take effect. And in the sense of being a quantum object, so is photo. I don't see why electron should deviate from geodesics in a way to prevent it from being absorbed). I strongly recommend you investigate this carefully and contact the authors of the previous works directly if convenient. I don't think their using of the word "emit" as oppose to "absorb" is due to a mistake or omission.
As for the possible restrictions coming from spherically symmetric solutions. I agree it doesn't falsify hep-th/0506214, I provided that point only as a random comment.
宠辱不惊，看庭前花开花落
去留无意，望天空云卷云舒
| 发表时间：2005-07-10, 21:54:45 |
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轩轩
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Re: 我们最近在写一个可能很重要的文章！！！
我的一点杂乱的想法
1。黑洞不吸收电子？？这是不是因为电子存在，严格意义上时空流形的协变导数算子不再是无扰的。这样的话，对测地线方程有变化？？
2。文章的第一个式子贝肯司坦猜想的黑洞熵谱与loop中的好象不一样，loop中是带根号j（j+1）的。哪一个是正确的？
3。要谈黑洞的宇称，先要把黑洞写成一个波函数，才能谈。如何写？
4。单说空间反演，在弯曲空间是什么样子的？？？
5。这些算子，全作用在哪一个hilbert空间之上？
6。经典黑洞应该没有宇称？？但可以用电荷，它的ADM4质量是类空无限远那一点的矢量，那么带上电荷以后，电荷可以看成类空无限远那一点的什么？？？？如果有宇称……
我无知到了只懂相对论了。
http://zhangxuanzhong.blog.edu.cn/
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i will love you till the null infinity.
| 发表时间：2005-07-10, 22:27:21 |
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THANXmm
