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主题:【原创】量子生物学 I 摘要和前言 -- witten1

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                    • 家园 没有所谓的完成的理论

                      so far, the only "complete" theorectical science we have is sr,can we say that?

                      我不相信当前有任何理论是"complete"的,我也不相信人类真能最终理解“真理”。当前的所有“正确”理论都只是在其适用范围内能非常好work的理论。就我个人的看法是量子力学能work的范围肯定比狭义相对论大,相对论怎么看都像是某种东西的coarse graining。相对论迟早有一天会被某更深层次的理解超越而只能做为某种有效近似,不然如此浩瀚宇宙,人类只能被困在一隅(即便以接近光速飞行),那这岂不是会非常无趣。而量子力学应当会在某个更深层的理论中直接留下影子而不只是做为某种有效近似。

                      • 家园 I mean qft

                        1.I was thinging about "quantum effect", "quantum communciation" as "non sr qm":

                        where there is "energy(or information) gap in terms of scales, "orders" ) between"local quantum system" and its environment, in a "low speed" micro qm model, such gap can hang on for quite a while as we know;

                        2. In a qft modeled world, a "gap" as such if any, in terms of spacetime seperation (space time separation four-vector), would exits like "casimir effect", but it is 6次方反比? you wrote about "casimir effect"once and very well.

                        3. "qft"as such a perfect information world, a realistic world or "high speed micro" sr qm model, there would be no life or bio stuff, then we have "big bang", higgs,对称稀缺, dark matter/energy/accouting error, etc?

                        4. I guess "higgs field" or adam/apple story is what 人择原理 about, we came from a information perfect world to the present information imperfect world, so we can progress or regress?

                        5. now, tg as a huge 薛定谔猫, what would be "penrose objective reduction"費曼路徑積分 model? mind boggling?

                        • 家园 QFT有一堆问题

                          只是大家都避而不谈罢了。

                          quantum field的局域性和量子理论的非定域性在本质上是互相矛盾且无法调和的。我在前面介绍Buchanan的一篇科学时评里谈到了这个----无论荷载纠缠态的两粒子距离多远,纠缠态总是关联collapse。Gisin刚刚完成的实验表明如果两粒子之间真有我们时空之中的某种隐藏的相互作用(隐参数)联系,那么这隐藏的相互作用的传播的速度必需是无穷大。这是QFT无法回答的一个问题。

                          Casimir效应的预测不需要QFT,通常的量子力学就够了。QFT所给出的预测都只是低能激发,即便像Higss粒子这样的东西也只是低能激发,谁也不知道到真正的Planck尺度的时候会发生什么。各种各样的理论都只是为我们理解这个世界提供各式角度,不要陷的太深,要跳出来的,平等对待一切“祖传秘方”,“奇丹秘丸”,充分明白它们的长处和短处,充分明白可做不可做,可理解不可理解的边界,无疑对自己会很有帮助。理论永远只是理论,而自然永远是自然。一句话勿把他乡(理论)当故乡(自然)。

                          共勉。

              • 家园 一些回答

                生命所能生活温度尺度不等于非相对论性量子力学。这里我只是说非相对论量子力学规范了我们地球上的碳基生命所能生存的温度范围。

                因为室温300K所对应的能标大约是25-26meV(It's very easy to get it, you just simply times 300K by Boltzmann constant then you get the energy scale, then simply convert it into eV = 1.6*10^(-19)J)。那么你应当知道这25-26meV对于大分子蛋白质意味着啥吧?在没有适当的保暖或抗热措施下,人类应当只能大概(裸)生活在300K plus/minus 40-50K的环境下,这对应的的能量的变化范围大概是21-30meV。我们也清楚,在超越这样的温度范围后,蛋白质会变性(不能正常工作了),而当你把它转到21-30meV,其实就是对应于蛋白质或者体内的别的大分子的在维持自身特性所必需存在的能级范围。所以说量子力学第一次真正解释了为什么我们只能生活在这样的温度范围。

                关于你的第三个问题,我没有相关资料,所以我无法回答。但是要说启发其实也是有一定道理吧。

                别把QFT放进来,生物体内的绝大部分或者说应当所有活动(这是我自己的断言)应当都不需要QFT。

                • 家园 indeterminacy plays no role

                  I believe this is still the foundation of mordern western medicine.

                  traditional chinese medicine would not agree with that?

                  and it seem that Schrdinger does not care much about "soul" etc, not as much as penrose does?

                  I hope you can translate this article into chinese, thx in advance

                  "Schrdinger wrote that, contrary to the opinion held by some physicists, quantum indeterminacy plays no biologically relevant role in the space-time events in the body of a living being, except perhaps by enhancing the purely accidental nature in mutation, meiosis, and so on. The two major premises considered by Schrdinger are (a) the body functions as a pure mechanism according to the laws of nature; and (b) we also know that we are directing its motions, knowing fully the consequences of our actions and taking responsibility for them. From these premises, Schrdinger concluded that I (in the widest sense) am the person, if any, who controls the “motion of the atoms” according to the laws of nature. "

                • 家园 incomplete without qft?

                  understood.

                  but mentally, our brain model would be "incomplete" in pure bio sense, since our body is not aware of the full picture of universe, or interacting with it, due to said energy related reason, we're 温室动物 ;

                  mentally though, we have had a, ll the great interactions with universe already, up to standard model, lab and evidence based..

                  I try to say that since "begining" , human mind is somehow aware of the fact that his operating model is "math incomplete" in relation to the universe or his "macro system", therefore fear and greed, religion, family, group power come in to "compensate" the incompletemness of his mind model..

                  science and technology progress can help, but the "gap" is never going to be narrower?

                  never ending pursuit of "negative entropy" for individual or human race? born to work and work to die?

          • 家园 生命, as "non sr qm"

            "生命所能生活温度尺度已经被体内的DNA大分子或者别的蛋白质分子所能保持稳定的能级范围给固定死了"

            I mean:"I remember you wrote some where that 量子场论 would have NO impact on the life on the earth as we know"

            also, I have to say I am a "民科" here, just asking some general questions.


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        • 家园 how about penrose reduction?

          always enjoyed reading your writings, thx;

          I have read a few on "qm and brain" subject, not sure if u are interested, copied in the following:

          Orchestrated Objective Reduction of Quantum Coherence in Brain

          www.quantumconsciousness.org/penrose-hameroff/orchor.html

          by S Hameroff - Cited by 411 - Related articles

          We take the view (Penrose, 1994) that, to address this issue, a new physical ingredient (objective reduction: OR) is needed in which coherent quantum systems ...

          quantum physics in neuroscience and psychology - Physics Division ...

          www-physics.lbl.gov/~stapp/PTB6.pdfSimilar

          You +1'd this publicly. Undo

          File Format: PDF/Adobe Acrobat - Quick View

          by JM Schwartz - Cited by 148 - Related articles

          QUANTUM PHYSICS IN NEUROSCIENCE AND PSYCHOLOGY: A. NEUROPHYSICAL MODEL OF MIND/BRAIN INTERACTION. Jeffrey M.


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        • 家园 是啊,如果能在生命体中发现宏观量子效应,一定会很有趣

          我之所以分出两种量子生物学(后面狂想的量子场生物学不算),就是因为我脑中有两个非相对论量子多体问题研究的范式:化学 和 凝聚态物理(特别是那些展现宏观量子效应的东西)。 我感觉 现有生物学基本使用的是化学,所以如果有能超越化学的(比方说)宏观量子效应的东西出现 是很好的事。

          可是另一方面我感到,化学范式上的生物学我们了解得还太少,而已知的很多最重要的生物学机制应该都是需要用这个范式来阐释的。因此我也很希望第一种量子生物学的发展。

          另外 关于从量子力学基本原理薛定谔方程出发直接导出流体力学方程 现在已经可以做到了。比如Harvard的姚鸿泽教授在十来年前从薛定谔方程直接导出流体力学的Euler方程。最惊人的是, 他既不需要以分子运动论Boltzmann方程作跳板,也不需要先取半经典近似过渡到牛顿力学。 他因为这工作(和其他一些工作)获得了Poincare奖。很多物理学家可能都不知道 姚鸿泽这类数学物理学家近年来在这些方面取得的重要进展,因为这些人基本都在数学系任职 而且工作都是艰深的分析类纯数学。其实这些工作对一线物理学家可能也没有直接用处, 但对于证明现有体系的内部和谐性还是很重要的。

          通宝推:晴空一鹤,
          • 家园 几乎肯定,在生物脑活动中可以观察得到宏观量子效应

            别的我不知道,但是,我相当肯定地相信(不是认为,是相信)在脑活动中,量子效应会起作用,说不定还是相当重要的作用。

            我们另有一帖讨论这个话题:围绕脑科学而发生的若干玄想链接出处

            可以通过那里的链接看到蒲慕明的演讲。从那里看,任何一个脑活动,将牵涉许多物理化学活动。如果追深一些,当然就是若干量子活动。由于尺度的关系,非常可能在某个环节,量子效应就体现为宏观的。而且,更由于这个情况,虽然人脑远比电脑具备处理信息的强壮性(鲁棒性,如果愿意用这个词的话),但是,既然是处理信息,必然在某地某时某刻,出现0或者1的效应,那就是说,这边是白天,那边是黑夜的这种效应,而0-1的取决,就是某种量子的起伏和波动。这样,量子效应就放大转化为宏观的。

            再讲一次,人脑比现有的电脑要具备高明很多的鲁棒性,那就是说,扰动很难产生实质性的信息处理上的区别。这是现在的电脑做不到的。但是,不管怎么鲁棒,还是存在一个小扰动就产生天上地下的差别的时刻和地方。

            你讲的这个从量子力学基本原理薛定谔方程出发直接导出流体力学方程,很有趣。是否你能够做一些更科普一些的说明,而不是仅给一个文献链接。比如说,不用统计近似,他是怎么从微观到宏观的?为什么仅能做到欧拉方程,不能做到纳斯方程?


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            • 家园 yes, I'm 4 脑活动中宏观量子效应,but

              1.

              Quantum computer

              basically=費曼路径积分 on a Bloch球面, with "qubit" all over 整个Bloch球面..etc

              Quantum computer - Wikipedia, the free encyclopedia

              en.wikipedia.org/wiki/Quantum_computer

              The Bloch sphere is a representation of a qubit, the fundamental building block of ... A quantum computer is a computation device that makes direct use of ... spins as quantum bits was also formulated for use as a quantum space-time in 1969.

              2.

              The weakness of Quantum computer' SE model: non sr, non qft, non gauge theory(規範場), particularly in the case of human brain as a Quantum computer

              Galilean invariance and the Schrdinger equation

              www.sciencedirect.com/science/article/pii/0003491660901068

              by M Hamermesh - 1960 - Cited by 34 - Related articles

              The Schrdinger equation is derived from the assumptions of Galilean invariance and the existence of a momentum operator acting within an irreducible ...

              3.

              The weakness of human brain (assuming its 宏观量子效应), in particular:

              Our human sense, logic, brain vision and computing is Galilean invariance-based, in general, and therefore we are trapped and boxed up

              @local gauge/fiber/位形空间 of a 时空流形...etc

              4. Now, "腦控"科幻

              assuming a 腦控 has some kind of 規範場 based model, can it "supervises" and "manages" those 腦

              trapped and boxed up

              @local gauge/fiber/位形空间 of 时空流形?

              kind of like we human being can manage a bird with a "super" quantum vision system, just because only we human being have science?

            • 家园 far from "几乎肯定":脑活动宏观量子效应

              -------------

              http://en.wikipedia.org/wiki/Orchestrated_objective_reduction

              "The main objection to the Hameroff side of the theory is that any quantum feature in the environment of the brain would undergo wave function collapse (reduction), as a result of interaction with the environment, far too quickly for it to have any influence on neural processes. The wave or superposition form of the quanta is referred to as being quantum coherent. Interaction with the environment results in decoherence otherwise known as wave function collapse. It has been questioned as to how such quantum coherence could avoid rapid decoherence in the conditions of the brain. "

              "Recently the debate has focused round papers by Reimers et al. [45] and McKemmish et al. [46] and Hameroff's replies to these,[26] which is not regarded as being independently reviewed. The Reimers paper claimed that microtubules could only support 'weak' 8 MHz coherence, but that the Orch-OR proposals required a higher rate of coherence. Hameroff, however, claims that 8 MHz coherence is sufficient to support the Orch-OR proposal. McKemmish et al. makes two claims; firstly that aromatic molecules cannot switch states because they are delocalised. Hameroff, however, claims that he is referring to the behaviour of two or more electron clouds; secondly McKemmish shows that changes in tubulin conformation driven by GTP conversion would result in a prohibitive energy requirement. Against this, Hameroff claims that all that is required is switching in electron cloud dipole states produced by London forces."

              • 家园 "小姑娘害羞":时间可达到1/1000纳秒

                1.

                from witten1

                http://www.ccthere.com/article/3830541

                "室温之下,在生物体内这样的一个复杂环境里,量子相干的维持的时间可达到1/1000纳秒,量子相干可比害羞的小姑娘还要害羞"

                2.

                有物理学家认为。欧亚鸲(European robins)的眼睛可能能够维持的量子纠缠,时间比先进的实验室设备还要长整整20微秒,这使得鸟们能够利用量子效应来“看清”地球磁场。

                所谓量子纠缠是指电子既在空间上分离但又能够相互影响的一种状态。有人提出欧洲鸲的眼睛里包含有一个基于纠缠态的“罗盘”,尽管还没有决定性的证据,但有一些侧证。

                为何在一个生命系统里能够进化出一个人类要在实验室里摆弄各种粒子才能搞出来的量子态?“这简直太令人惊奇了,”牛津大学的量子物理学家Simon Benjamin说道。

                很多鸟类、鱼类、爬行类、哺乳类,甚至甲壳类动物和昆虫都是靠地球磁场来寻找方向的。近年的研究发现了一种特殊光感细胞,这种细胞里含有一种称为隐花色素(cryptochrome)的蛋白质。当光子进入到眼睛时,会击中隐花色素,使处于量子纠缠态中的电子得到能量,移动数纳米,令其比它同处于纠缠态的同伴感受到略微不同的磁场;依磁场使得这个电子的旋转产生何种变化,会导致不同的化学反应。理论上,很多这类反应加在一起会使鸟类眼中以明暗不同的图像形成地球磁场的模样。

                不过,这类量子态是非常脆弱的。实验室中,原子被冷却到接近绝对零度的环境下时,也只能维持千分之几秒,生物系统明显温度和湿度太高,但量子态竟然仍旧能够存在——加州大学2004年的一篇论文显示,一个强度低于地磁场1/300、微弱到只能影响量子级系统的磁场仍然会导致欧亚鸲的方向感出现错误,最近Benjamin发表在《物理评论快报》上的论文则为这个实验建立了一个数学模型,指出要感受到如此微弱的磁场,鸟类眼睛里的纠缠态时间至少要达到100微秒(0.0001秒)。

                有一种被称作做N@C60的分子,结构是一个氮原子被碳笼所包裹,这是实验室里能维持纠缠态的分子,但在室温下也只能维持80微秒。只能说鸟类眼中的分子结构超过了我们精心打造的分子。

                3. aapl

                七彩虹的Colorfly Pocket HIFI C4作为第一款做到24 bit/192KHz的便携式HIFI播放器,同时集成了Jitter kill专利技术,在Jitter Kill的模块中,晶振上采用了昂贵的温补晶振以从源头消除Jitter。同时再配合上C4时钟发生器等,将Jitter降到极限的5皮秒以内。远远低于人类的听觉低限――50皮秒,而当前,主流的播放器(比如苹果)都在纳秒级别。(1皮秒=1/1000纳秒=1/1000,000,000,000秒)

                HIFI就要超越极限 C4抖动突破5皮秒

                作者: icE  来源: 本站原创  发布时间: 2011-4-21 18:16   

                HIFI的本意是“高保真”,即最高限度的还原录音时的现场,在如今的数码电声科技时代,抛弃了传统的机械装置的干扰后,仍然有很多因素阻挡HIFI的前行,但其中一种重要的因素便是Jitter,又叫抖动,是音乐和时间不同步的原因导致的一种失真,而且这种失真从机械时代一直持续到如今的数码时代。

                数字音频的基本原理就是把连续的模拟信号在离散的时间点上进行采样(Sampling),进而形成数字化的信息。时间是信号数字化的最重要的因素之一,采样和重放的时间准确度在很大程度上决定了模拟-数字转换(ADC)以及数字-模拟转换(DAC)的质量,但是现实中是不可避免的存在时间准确度出现偏差的问题,这便是抖动(Jitter)。


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          • 家园 兄弟如果直接知道是哪篇文章的话

            能否直接把那文章的链接发我?就是你所说的姚老师的在十来年前从薛定谔方程直接导出流体力学的Euler方程。

            因为我去年还在学校听了一个专门做这问题的一个家伙给的报告,他的结论是迄为止没有人从量子力学的基本原理能导出流体力学的基本方程,他最后甚至悲观的认为永不可能。考虑到他是专门做这个的,所以我采信了他的结论,他的悲观的看法我就置之不理了。

            PS:量子场论不会对地球上的生命有啥直接的影响。

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