d****n
发帖数: 397 | 1 首先申明不是大牛，只是对这方面感兴趣，基本没有实战经验。如果说错，还请版上大
牛斧正。
你要展开分子轨道，这个太难了。确实按定义应该这么算，但是要自己分析结果写程序
，为什么不用现有的软件算这个呢。
如果你有Molpro,我不知到怎么用Molpro,也没有权限，不过大致是这样的：里面有个
non-adiabatic coupling element calculation,就能算你要的
psie(r,Rref)>.psi(r,Rref)是diabatic wavefunction,g和e是正交的，但是不是H(r,R
)的本征函数（因为R!=Rref),所以coupling不为0，只有R=Rref的时候,g和e才是正交的
，这个时候coupling 为0。
如果你没有Molpro,有Gaussian,一般都能用Gaussian.但是Gaussian只能算adiabatic
states, 你能用adiabatic和diabatic之间转换来算这个coupling.这个coupling在
avoided crossing的时候最大。
所以可以用av... 阅读全帖 |
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m*******s
发帖数: 3142 | 2 有个问题困扰我很久了，
就是关于有限温度情形的所谓adiabatic connection(或者叫adiabatic switch on)的
可行性。
我看到有些场论的书，把这种情况的adiabatic connection类比于零温情况，理解成散
射过程，即自由粒子从负无穷的时间伴随着无限缓慢施加相互作用Hamiltonian，演化
到处于平衡态的有真实相互作用的系综，然后再开始的各种非平衡态演化。
这些话看似很有物理图像，特别是它把无法严格处理的多体体系转化成独立粒子体系，
确实很吸引人。 可是实际上它不能通过严格数学证明。
如果使用这个任何数学证明的假设去计算实际体系中各种nonstataionary物理量，会不
会让人指责是荒谬的？
不过直接从真实的系综出发来计算，肯定也要做一大堆近似，只是这些近似都是多体理
论里面获得普遍认可的近似。
我觉得尴尬的局面就是就计算模拟nonstataionary过程的结果来说，谁也不能肯定自己
就一定对，对方就一定错。大家遇到这种情形通常怎么办？
PS:补充一点，我刚才看到一些文献上说，孤立体系的adiabatic switch on同开放体系 |
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y********l
发帖数: 794 | 3 我想审第一个稿子，已经给联系人发信了。
我的研究方向是：thermodyanmics, calorimetry, thermochemistry, low
temperature heat capacity study using adiabatic, semi-adiabatic and
relaxation calorimetry.
多谢了！ |
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d****n
发帖数: 397 | 4 我差不多明白你想要什么了。你是不是想算从高激发态到低激发态的radiationless
decay?根据Landau-Zener Formula,
这个decay的probability(应该和decay速度成正比例），是和两个激发态之间coupling
element有关。P=exp(-
2*pi*a^2/(hbar*|alpha|).其中a就是coupling element。
这个a就是在avoid crossing时候，两个adiabatic state之间能量差的1／2。
gaussian里面opt选项里面可以，优化构型到conical intersection或者到avoided
crossing point. 我个人认为
opt=conical要和casscf一起用（至少在gaussian里面）。
然后在casscf的输出里面，查看casscf的eigenvalues，如果第一个激发态，和第二个
激发态能量一样，就是conical
intersection（照你的描述，应该不一样）。如果第一个激发态，和第二个激发态能量
不一样，就是avoided
crossing，cou... 阅读全帖 |
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d****n
发帖数: 397 | 5 我同意SEM的观点。gaussian里面是不会给出diabatic pes的，扫描势能面给出的应该
是adiabatic pes。
如果系统有对称性，可能有conical intersection。就像Jahn-Teller 效应里面两个势
能面相交于一点，这点的能量高，对
称性高（两个态是在该点是简并的），然后系统倾向于能量低的构型，就会有
distortion，对称性降低。
如果系统没有对称性，可能就是avoided crossing，avoided crossing那点的coupling
element，就是两个adiabatic 能
量差的一半。
因为 Hamiltonian matrix是（0 c）
（c 0）。
c就是coupling element。
这里c是实数。
如果两个diabatic state本来就不相交，应该就没有radiationless transition吧，如
果要从高激发态到低激发态只能通过
photon emission来实现吧。 |
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s*****V
发帖数: 21731 | 6 2011
ME316 Treatment of Simulated Cancer Cells with Compton Scattering-Produced
Secondary RadiatioN
2010
Young Scientist Award of $50,000
CS043 Automatic Parallelization through Dynamic Analysis
PH018 Adiabatic Quantum Evolution for NP-Complete and Physical Problems |
|
s*x
发帖数: 8041 | 7 D-wave号称有512qubit的量子计算机，但是真正搞quantum gate计算机的都对D-wave有
怀疑，甚至不屑一顾，因为学术界现在最多20qubit。一个是D-wave不是gate，而是
adiabatic,只能解决optimization问题，另一个是现在很难说D-wave到底有没有量子效
应。 |
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w********h
发帖数: 12367 | 8 除了中文wiki上说Sauer是Merkel的博士导师，
你能提供英文来源么？
Merkel和Sauer就合作过一篇web of science能查到的文章，
你说话能有点证据么？
VIBRATIONAL PROPERTIES OF SURFACE HYDROXYLS - NONEMPIRICAL MODEL-
CALCULATIONS INCLUDING ANHARMONICITIES
By:MIX, H (MIX, H); SAUER, J (SAUER, J); SCHRODER, KP (SCHRODER, KP); MERKEL
, A (MERKEL, A)
COLLECTION OF CZECHOSLOVAK CHEMICAL COMMUNICATIONS
Volume: 53 Issue: 10 Pages: 2191-2202 Published: OCT 1988
按照Merkel A来检索，共有9篇，
即便她后来没成为一个成功的物理化学家，
但得到的博士学位，是货真价实的！
1
THE LOWEST BOUND-STATES OF TRIPLET (BH2)+
B... 阅读全帖 |
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y***k
发帖数: 9459 | 9 真空零点能好像没那么玄幻，现在已经有不少进展了。
Understanding the reaction between muonium atoms and hydrogen molecules:
zero point energy, tunnelling, and vibrational adiabaticity
DOI:10.1080/00268976.2013.815399
J. Aldegundea, P.G. Jambrinab*, E. Garcíac, V.J. Herrerod, V. Sáez-Rá
banose & F.J. Aoizb*
pages 3169-3181
Publishing models and article dates explained
Received: 18 Apr 2013
Accepted: 10 Jun 2013
Accepted author version posted online: 27 Jun 2013
Published online: 16 Aug 2013 |
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o*****p
发帖数: 2977 | 10 退火算法好像已经证明和量子算法等价。所以也能算量子计算机。
Aharonov D, Van Dam W, Kempe J, et al. Adiabatic quantum computation is
equivalent to standard quantum computation[J]. SIAM review, 2008, 50(4): 755
-787. |
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s*x
发帖数: 8041 | 11 Their claimed speedup over classical algorithms appears to be based on a
misunderstanding of a paper my colleagues van Dam, Mosca and I wrote on "The
power of adiabatic quantum computing." That speed up unfortunately does not
hold in the setting at hand, and therefore D-Wave's "quantum computer" even
if it turns out to be a true quantum computer, and even if it can be scaled
to thousands of qubits, would likely not be more powerful than a cell phone. |
|
发帖数: 1 | 12 楼主想创造adiabatic process
把你先放进去，看看活几分钟哦！
250
W |
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c*********r
发帖数: 19468 | 13 similar, in a way
essentially, you're dancing between two different adiabatic processes
the work you can get depends on their difference
to take more advantage out of it, you gotta push the starting point of the
expansion stage leftwards as much as possible, i.e. increase the compression
ratio whenever you have a chance |
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c******n
发帖数: 5697 | 14 adiabatic expansion cooling of gases |
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f**********e
发帖数: 1994 | 15 adiabatic expansion from thermodynamics |
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b*******t
发帖数: 33714 | 16 前面加一段小的，couple进去然后adiabatically taper成50um的低阶模吧。
刚才看错单位了 @__@ |
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s*****V
发帖数: 21731 | 17 【 以下文字转载自 Military 讨论区 】
发信人: saturnV (土星五号), 信区: Military
标 题: 你以为在美国高中就能毕业了？
发信站: BBS 未名空间站 (Wed May 2 03:26:35 2012, 美东)
2011
ME316 Treatment of Simulated Cancer Cells with Compton Scattering-Produced
Secondary RadiatioN
2010
Young Scientist Award of $50,000
CS043 Automatic Parallelization through Dynamic Analysis
PH018 Adiabatic Quantum Evolution for NP-Complete and Physical Problems |
|
s***e
发帖数: 911 | 18 ( sorry I have to write this part by english).
Definition 1. adiabatic wall---If a system is surrounded by the adabatic
wall, it is
said be thermoally Isolated. No energy enters a thermolly isolated system.
Definition 2. Equilibriums:
2-1: Thermal equilibrium: There is a flow of energy between systems which
eventually balances and the flow stops. This final state is call the
thermal equlibrium.
2-2: mechannical equlibrium: the volumes of each system changes until a
balance is reached and the vol |
|
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F********y
发帖数: 400 | 20 其实都是大学物理基础课的东西吧...我虽然是三年前学的不过因为物理很有爱所以记
忆还是很深刻啊,那些adiabatic和entropy什么的.
嘛,新FE土木的话我就不能靠复习这些东西刷分要硬上纯土木的东西了,虽然还是有很多
基础的比如数学力学什么的,但是热力学啊电磁学啊化学都基本被取消了. |
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l***o
发帖数: 7937 | 22 Johnson-Cook material model is often used for high-speed projectile
penetration. This model has temperature as a variable to consider material
softening (melting), assuming adiabatic conditions. |
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d*a
发帖数: 1863 | 23 中心吧 如果四周是adiabatic的
不研究固体力学 瞎说的 |
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w********i
发帖数: 1721 | 24 刚wiki 了下adiabatic process. 看来这个问题还挺复杂的。比如说绝热自由膨胀那个
例子，wiki解释自由膨胀对外做功是0,所以温度不变，没有热量传递，在等温下熵和体
积成正比，所以熵增。这种熵定义我以前工热没讲到过......
wiki一下entropy发现这玩儿定义挺复杂的。不是dq/t那么简单 |
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m**k
发帖数: 1008 | 25 2010年诺贝尔物理奖（预测）揭晓
已经到了今年的诺贝尔奖揭晓之时，每年大家都议论纷纷。这里大呆凑个热闹，大胆
地预测一下今年的诺贝尔物理奖。今年应该颁给Yakir Aharonov和Michael
Victor Berry。得奖理由：由于在Aharonov-Bohm效应和Berry相效应方面的杰
出贡献。
得奖论文：
标题: SIGNIFICANCE OF ELECTROMAGNETIC POTENTIALS IN THE QUANTUM
THEORY
作者: AHARONOV Y, BOHM D
来源出版物: PHYSICAL REVIEW 卷: 115 期: 3 页: 485-491 出版年: 1959
被引频次: 2,932
标题: QUANTAL PHASE-FACTORS ACCOMPANYING ADIABATIC CHANGES
作者: BERRY MV
来源出版物: PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-
MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 卷:... 阅读全帖 |
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l*b
发帖数: 4369 | 26 量子计算要想做到有人用，怎么也得能对抗当前的RSA编码吧，好像一般是256bit强度
？那就得几百个qubit。但是要想对抗decoherence，还得上QECC，用CSS的话就是7倍冗
余。不知道这个fault tolerant quantum computation现在搞得怎么样了。
现在好像比较热的是用adiabatic方法的量子计算，实现难度低一点吧。
00年前后是量子信息的大发展啊，现在差不多开始凉快了。 |
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w*****1
发帖数: 220 | 27 Dear Readers,
We are happy to present the first five papers that are published in our
new, open access journal, Physical Review X. These papers, together with
others that are to be published in the coming weeks into September, will
constitute the first issue of the journal. Under PRX's open access
publishing model, they are free for you to read and use.
We are very encouraged by the breadth of their topical spread. It ranges
from the well-established field of atomic, molecular and optica... 阅读全帖 |
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l*b
发帖数: 4369 | 28 it is adiabatic computation. finding (approximate) global minimum by keep
perturbing the quantum state. It can be more powerful in certain
optimization problems.
回国马上就能拉一大笔经费 in quantum information is an inspiring dream,
unless you are close with ppl like Guo/Pan/Yao |
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c****u
发帖数: 584 | 29
=sqrt(8kt/PI*m); sqrt=sqrt(3kt/Pi*m)
It depend on the process, I guess if it is adiabatic process
U can calculate the change of temperature and then useing fomula above to
get the speed. |
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c**********g
发帖数: 222 | 30
>>> it is proved that the freely expanding (adiabatic expansion)
photon field
will remain the balckbody spectrum and in thermal equilibrium as long
as it is
in equilibrium at the begining. You can try to prove it. it is fun.
>>>> yes, the photon energy is not conserved. The energy density drops
at the
rate of V^(-4/3) or (1+z)^4 or a^(-4). V is the considered volume. a
is the scale
factor. for the ideal fluid with p=w \rho. (w is a constant. \rho is
density and
p is pressure), then \rho drop |
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