三个月前,笔者有一篇高温超导论文[1]发表在Nature出版集团的《Scientific Reports》上,该文推导出超导临界转变温度Tc与材料(临界温度以上)强关联区霍尔电阻率p之间的标度关系。此文发表后,笔者对于在实验上证实这一标度关系非常有兴趣,所以迫切期望得到超导实验界同行的反馈。基于这个目的,笔者联系了美国布鲁克海文国家实验室和MIT相关实验室主管,并得到他们的积极回应(当然他们现在是否在做这个实验我还是不知道,美国人说话总是比较客气的)。 在此期间,笔者倒从未得到国内物理同行的回馈。由于有其它研究工作要做,精力有限,笔者对超导论文后续实验的关注也就暂时冷了一段时间。不过,让人意外的是,后来笔者居然收到一位药学“国家杰青”教授对笔者论文的“评价”。事情的起因是,笔者这篇《Scientific Reports》上的论文在学校主页上打了一个科技新闻。当时笔者内心倒是觉得该“标度定律”是首次面世,也值得打一个广告,相比于那些“不痛不痒”的广告论文,笔者对自己的成果倒是很有信心的(中国有句古话:不是猛龙不过江)。在笔者看来,它是笔者最得意的四个原创工作之一(见文《我写在祖国的四篇代表性论文》)。 但是这一新闻却引来了一位药学“国家杰青”教授的强烈批评,并最终导致笔者科研成果的新闻在公布几天之后便被下架了。笔者大感惊奇,所以甚想倾听该教授的“批评意见”。但是一听之下,却大感失望。 该药学“国家杰青”教授的批评意见是:《Scientific Reports》是交1万块人民币就可以发论文的烂期刊,所以笔者的研究成果太差。 笔者有兴趣查了一下该教授的研究领域:化学及生物医药分析。一位可能连“朗道-金兹堡方程”与“重整化群分析”都不知道的教授,居然可以评判一篇高度专业的超导场论论文。而他依赖的凭据就是“《Scientific Reports》是烂期刊”,仅此而已!笔者认为这一案例已经极大的反映出了国内科研评价的某种“偏执”(只看期刊不看文):以至于一位“生物医药”教授可以评判一篇“高温超导”专业论文的优劣。 借此博客,笔者也想回应一下那位药学“国家杰青”教授的批评:要是《Scientific Reports》真是交1万块人民币就可以发论文的期刊,那笔者最得意的工作之一“量子本性”[2]就不会发表在《ScienceOpen Research》这一非SCI期刊上了。
俗话说:东方不亮,可能西方就会亮。
1个多月前美国科学媒体《超导周刊》(Superconductor Week)的主编Klaus Neumann注意到了笔者发表在《Scientific Reports》上的“标度定律”在超导工业制备中的潜在应用价值,所以希望采访一下笔者。笔者内心当然是很希望“标度定律”可以被用于制备高温超导的,所以接受了采访,而且笔者也有一些想法希望与“微观超导领域”的学者分享。《超导周刊》(Superconductor Week)对笔者的访谈出版在2016年6月7号刊。下面贴出全文(笔者仅翻译出希望与“微观超导领域”学者一起分享的想法):
Southwest University Models Competition Between Disorder and SC Yong Tao, Researcher at Southwest University in Chongqing, China, has proposed the use of a Lagrangian function, which combines the Landau-Ginzburg and Chern-Simons term, for describing the competition between disorder and superconductivity. Tao applied Wilson’s renormalization group methods to the Lagrangian function to describe the normal-to-superconducting transition in superconducting thin films. Tao also obtained a scaling law between Tc, film thickness, sheet resistance of the film in the normal state, and number density of the electrons at the normal state. The scaling law is in agreement with recent experimental investigations [Ivry, Y. et al, Physical Review B 90, 214515 (2014)]. Tao said that the findings may help raise Tc in HTS materials. Goal to Understand Physical Laws Around SC/Disorder Transition “The main purpose of this research is not to give a response to the difficulties of describing the competition between disorder and superconductivity,” commented Tao. “ In fact, this research mainly investigates what physical laws will occur around the transition point between disorder and superconductivity. (译文:陶谈到:“这篇论文的主要研究对象并非针对‘无序与超导’之间的竞争机理。事实上,我主要想调查超导临界点会显现出怎样的物理定律”。)
“In the past, many condensed matter physicists paid more attentions to micro-mechanisms that trigger HTS. They believed that the Tc could be substantially raised if and only if the underlying micro-mechanisms could be clarified. Physicists have proposed many theories involving different sorts of micro-mechanisms for explaining HTS, but so far concrete advances that raise the Tc have only slowly been realized. (译文:“在过去,很多凝聚态物理学家都花费太多的精力去研究高温超导形成的微观机理。他们大多都相信只有高温超导的微观机理被搞清楚,才有可能极大的提升超导转变温度。遗憾的是,尽管这些凝聚态物理学家们已经建议了各种各样的高温超导微观理论,但是提升超导转变温度仍旧进展缓慢。”)
“Instead of analyzing different sorts of micro-mechanisms, my research is merely a phenomenological work. I have no interest in clarifying micro-mechanisms, but want to know what physical laws will occur around the transition point. If these physical laws exist, they must be the necessary conditions for HTS, and by utilizing them one should be able to manufacture HTS.” “This case resembles the invention of steam engine. As is well known, macroscopic thermodynamics is a phenomenological work, but it has provided all the necessary conditions for materializing a working steam engine. Because of their understanding of thermodynamics, eighteenth-century engineers didn’t have to wait until Boltzmann clarified the micro-mechanisms of macroscopic thermodynamics to manufacture a working steam engine.” (译文:“与那些试图破解出‘高温超导微观机理’的雄心相比,我的研究仅仅只是一个唯象工作。我并没有任何的兴趣去破解出‘高温超导微观机理’,而仅仅只是希望搞清楚超导临界点会发生怎样的(宏观)物理定律。如果这些定律确实存在,它们必定是形成高温超导体的必要条件。因此,依靠操控这些定律的变量就有望制备高温超导”。 “我所建议的方案非常类似于‘蒸汽机’的制备。众所周知,尽管宏观热力学仅仅只是一个唯象工作,但是它却提供了制造‘高效可兹利用的蒸汽机’的必要理论基础。正因为宏观热力学的出现,18世纪的工程师并不需要等到玻尔兹曼发明出‘宏观热力学的微观基础’(统计物理学)才去制造‘高效可兹利用的蒸汽机’”。)
First Study to use Lagrangian Function to Describe HTS Tao added that he believed he was the first to suggest the use of a Lagrangian function to describe HTS: “Chern-Simons theory has been used to describe the Fractional Quantum Hall Effect (FQHE) when considering a 2+1 dimensional space-time. Different from FQHE, my model is established in a 3D space, and the Chern-Simons gauge field is considered as the electromagnetic field. Nevertheless, in FQHE the Chern-Simons gauge field is considered an imaginary field. “The Lagrangian function in my model can only describe a superconductor which is a strongly correlated electron system. HTS is such a system. Unlike LTS, HTS has a characteristic temperatureT* which is larger than the Tc: when the temperature lies in between Tc and T*, electron pairing has materialized. “In my opinion, such a temperature interval implies a strongly correlated electron system, which will induce the emergence of the Chern-Simons gauge field. My model thus mainly describes the temperature interval [Tc, T*], where T*>Tc. However, if T*=Tc, then my model is unnecessary.” Scaling Law to Help in Search for HTS Tao also touched on the importance of his proposed scaling law: “To the best of my knowledge, the scaling law in this study is the first such scaling law proposed for HTS. It emphasizes that the Tc will be inversely proportional to Hall resistivity in a temperature interval [Tc, T*]. By contrast, the existing experimental investigations only confirm a similar scaling law wherein Tc is inversely proportional to the resistivity at the normal state. “The scaling law in this research indicates that the Tc will be inversely proportional to Hall resistivity in a temperature interval [Tc, T*]. This means that the search for HTS should be concentrated on materials whose Hall resistivity in the temperature interval [Tc, T*] is sufficiently small. Unlike the theories of micro-mechanisms, my scaling law describes macroscopic physical variables and will therefore be easier to test or use in industrial production. “In my opinion, the next step in this line of research is to test if the Chern-Simons gauge field emerges in the temperature interval [Tc, T*]. If the Chern-Simons gauge field indeed exists at such a temperature interval, my model has the potential to become a basic theory for describing HTS.”
尽管笔者的超导工作被学校的新闻网下架,但是它最终还是出现在了美国科学媒体《超导周刊》上,这不能不说是一件有意思的事情。任何的科研成果最终都是服务于社会的,我想在这一点上美国《超导周刊》做的非常好:Superconductor Week is the newsletter of record for the superconductor industry, covering technical advances, commercialization, and business in every sector and every country developing superconductor technologies. Superconductor Week is delivered to the desks of leading executives, investors, researchers, and policy-makers around the world, 24 times a year. 笔者的高温超导标度定律最终总会被实验所证伪。目前的实验已经证实了超导转变温度与电阻率间的标度关系。笔者的工作是得到超导转变温度与霍尔电阻率间的标度关系。笔者之所以将其列为自己的四个原创工作之一,是因为看到了这个工作的深度:任何的超导微观理论都可以(按格林函数方法)退化为“宏观朗道-金兹堡方程”(只是系数不同而已),而描述“强关联系统”的天然场论似乎最完美的就是“陈-西蒙斯规范场”。笔者的理论结合“朗道-金兹堡方程”与“陈-西蒙斯规范场”,按照“重整化群分析”确定了各个系数间的“临界宏观定律”,这是具有相当普适性的。假如有一天,“寻找各种宏观高温超导定律”这一领域可以兴起,那么笔者的工作必定是一道迈不过去的坎。 最后,至少笔者是不敢对“化学及生物医药分析”领域内的论文做评价的,因为笔者确实不懂。 好吧,慢慢等实验结果。
我的超导论文见链接:http://www.nature.com/articles/srep23863
正文所列论文: [1] Yong Tao, Scaling Laws for Thin Films near the Superconducting-to-Insulating Transition, Scientific Reports 6 (2016) 23863 [2] Yong Tao, Testing for Wilson's quantum field theory in less than 4 dimensions, ScienceOpen Research (2015) 本文作者:陶勇
从药学“杰青”教授评判“高温超导”论文谈起 |