龚鹏程对话海外学者第十二期：在后现代情境中，被技术统治的人类社会，只有强化交谈、重建沟通伦理，才能获得文化新生的力量。这不是谁的理论，而是每个人都应实践的活动。龚鹏程先生遊走世界，并曾主持过“世界汉学研究中心”。我们会陆续推出“龚鹏程对话海外学者”系列文章，请他对话一些学界有意义的灵魂。范围不局限于汉学，会涉及多种学科。以期深山长谷之水，四面而出。
尼拉德里·沙克
印度加尔各答大学理学学士(2006年)，获Serampore学院物理奖。理学硕士。2008年哈拉格布尔印度理工学院物理学硕士。2009年博士前课程（理学硕士后）印度萨哈核物理研究所。2014年加尔各答大学萨哈核物理研究所博士。
后担任该所理论部研究助理。继而在德国德累斯顿马克斯·普朗克复杂系统物理研究所、法国巴黎居里研究所、荷兰莱顿大学洛伦兹研究所，担任博士后研究员，并教授时间相关统计力学、凝聚态物理等课程。
组织或参与第12届EBSA联合会、第10届ICBP-IUPAP生物物理学大会（西班牙）、物理和生物系统（法国伊维特Gif）形态发生的物理生物学-力学、代谢和信号等会议和讲座。
龚鹏程：谢谢你参加这次对话项目。您能介绍一下您的研究领域和您的兴趣爱好吗?对您这个领域，了解的人一定不多。
尼拉德里·沙克：龚教授，您好。首先，谢谢你邀请我参加这个对话项目，非常高兴能够参与。
我研究领域涵盖的是软物质物理和生物物理的交叉领域。软物质研究，是经一些非常有名的科学家发展起来的，像皮埃尔·吉勒·德热纳(1991年诺贝尔物理学奖得主)和雅克·普罗斯特。他们十分了解物理和流变特性的材料例如胶体、凝胶、泡沫，甚至液晶(后来被广泛用于电视显示)。软物质研究不仅涉及如何在实验中量化和测量泡沫和凝胶的粘度、弹性或塑性等特性，而且还涉及详细的理论框架来理解这些属性依赖什么一般参数而存在，以及是什么使这些泡沫或凝胶不同于像水这样的正常流体。
在20世纪末，科学家们发现，软物质、统计物理学和流体力学的概念可以用来理解细胞、组织和器官等生物单位的物理学，因此生物物理学诞生了。生物物理学主要研究与这些生物材料相关的统计和力学特性，这些生物材料，构成了我们周围看到的所有生物物质。例如，基因活动和表达如何依赖于外部刺激，以及癌症或肿瘤如何形成，是当前生物物理学研究的两个热门分支。
在我的研究生涯中，我主要感兴趣的是了解物理过程如何在细胞和组织中发生。例如，细胞如何感知机械力，并将细胞外的化学信号传递到细胞核内。这是一个复杂的物理问题，一直是我的研究兴趣之一。我也对理解一组细胞的机制以及它如何最终形成像组织这样的多细胞结构很感兴趣。我经常使用来自软物质物理学和流体动力学来回答这些问题。
First of all, thanks for inviting me for this program. It's my pleasure to participate in thisprogramme.
My research area covers an interdisciplinary field of soft matter physics and biophysics. Soft matter was developed mainly by scientists like Pierre-Giles de Gennes (who is the Nobel Prize laureate in physics in 1991) and Jacques Prost, to understand the physical and rheological properties of soft squishy materials like colloids, gels, foams, and even liquid crystals (which were used extensively in television displays afterwards). Soft matter research deals not only with how these properties for e.g., viscosity, elasticity, or plasticity of foams and gels are quantified and measured in experiments, but also with elaborate theoretical frameworks to understand what generic parameters these properties depend on, and what exactly makes these foams or gels different from a normal fluid like water.
In the late 20th century scientists also figured out that concepts from soft matter, statistical physics, and fluid mechanics can be used to understand the physics of biological units like cells, tissues, and organs, and thus biophysics was born. Biophysics deals mainly with statistical and mechanical properties associated with these biological materials which make up all living matter that we see around us. For example, how gene activity and expression depend on external stimuli, and how cancers or tumours form are two popular branches of current biophysics research.
Throughout my research career, I had been mainly interested in understanding how physical processes take place in cells and tissues. For example, how cells can sense mechanical forces and transmit chemical signals from outside the cells to inside the nucleus is a complex physics problem and has been one of my research interests till now. I have also been interested in understanding the mechanics of a collection of cells and how it ultimately gives rise to a multicellular structure like tissue. I have often used concepts from soft matter physics and fluid dynamics to answer these questions.
龚鹏程：流体力学/物理学，在生物物理学研究中扮演什么角色?流体力学/物理学如何帮助我们理解生物物理学?你能给我们举几个例子吗?
尼拉德里·沙克：生物系统中最小的单位被认为是细胞。我们可以进一步从长度体量上来说，细胞是由蛋白质、氨基酸、原子和分子组成的。但要理解这些非常小的亚单位，比如只有几微米大小甚至更小的细胞，他们如何分裂并自我组织从而形成更大的多细胞结构（如组织或器官），是生物物理学中最重要的基础问题之一。这种自组织的核心是一种集体行为，它让我们把细胞看作可以移动、流动和显示复杂属性的场，就像复杂的流体一样。细胞流动对于理解组织形态或形状是如何随时间发展的，或者癌症转移是如何发生的很重要。
例如，当癌症形成时，原发肿瘤部位的恶性细胞通过血流进入其他器官和组织，并在那里开始分裂，最终转移它们。在物理术语中，我们倾向于说一组细胞在长时间和长尺度下具有粘性或流体性质，而在短尺度下具有更大的弹性或固体性质。
这种类似流体的行为允许我们使用流体力学及其概念，如Navier-Stokes方程，来对细胞和组织进行理论建模。人体不仅有细胞和组织，还有大量的组织液、水和血液，它们的流动和性质只能从物理角度用流体力学来理解。
The smallest units of a biological system are considered to be cells. One can go even further down the length scales and say that cells are made up of proteins, amino acids, and atoms and molecules. But to understand how these very small subunits like cells which are a size of a few micrometres or even smaller divides and self-organize themselves to form bigger multicellular structures like tissues and organs is one of the most important fundamental questions in biophysics. And at the heart of this self-organization is a collective behaviour that makes us consider cells as fields which can move around, flow, and display complex properties just like a complex fluid. And cell flows are important to understand how a tissue morphology or shape develops over time, or how cancer metastasis takes place.
When a cancer is formed for example, malignant cells from the primary tumour site flow through the bloodstream into other organs and tissues and start dividing there, ultimately metastasizing them. In physical terms we tend to say that a collection of cells has viscous or fluid like properties at long time and large length scales, and more elastic or solid like behaviour at short length scales.
This fluid-like behaviour allows us to use concepts of hydrodynamics and fluid mechanics like the Navier-Stokes equation to theoretically model cells and tissues. Not only cells and tissues, but there is an ample amount of interstitial fluid, water and blood present in the human body, whose flow and properties can only be understood from the physics perspective using fluid mechanics.
龚鹏程：中国科学院一位院士曾说，95%的医疗设备都是由物理学原理设计的。您想谈谈物理学是如何应用于医学研究和设备的吗?
尼拉德里·沙克：物理学在人类制造的所有仪器中都有着深远的影响，包括医疗仪器。不仅是仪器，我们周围看到的几乎所有东西都可以从物理学的角度来解释。
如果我们谈论医疗器械，从这些器械的校准到医疗数据的测量和量化都涉及到物理学。以x射线为例。要理解x射线，我们首先需要认识到它是电磁波辐射，其波长比可见光要小得多。这需要物理学的知识。电磁学本身是物理学的一个分支。
接下来，为了理解x射线辐射的基本概念，我们再次需要物理学知识来了解电子是如何于真空中在放置于x射线管的电极之间加速的。以及这些加速的电子如何最终产生x射线形式的辐射。
另一个例子是磁共振成像(MRI)，它广泛用于人体成像，以检测肿瘤和一些其他的生理状况，比如中风、肌肉或关节异常。这种技术使用了射频发射的概念，由一个特定的原子核，如氢原子，放置在一个外部磁场中。由于人体尤其是水和脂肪中含有大量的氢元素，所以磁共振成像仪基本上可以绘制出人体中水和脂肪的位置。
这又是一个巧妙方法的例子，该方法利用物理学原理来探测人体，并识别其他方法难以检测到的异常。有很多公司生产医疗器械，比如飞利浦，它有自己的医疗产品系列，比如CT扫描仪、磁共振成像机、x光机和断层扫描机等等。
Physics has a profound presence in all instruments built by humans including medical instruments. Not only instruments but almost everything that we see around us can be explained from a physics perspective.
If we talk about medical instruments, starting from calibration of these instruments to measurement and quantification of medical data involves physics in it.For example, consider X-rays. To understand X-rays, we need to first realize that it is electromagnetic radiation whose wavelength is much smaller than visible light. This requires the knowledge of physics. Electromagnetism itself forms one of the branches of physics.
Then to understand the basic concept of X-ray radiation, we again require the knowledge of physics to know how electrons are accelerated between electrodes which are placed in a vacuum in an X-ray tube. And how these accelerated electrons finally produce radiation in the form of X-rays.
Another example is Magnetic Resonance Imaging or MRI which is used extensively for imaging the human body to detect tumours and physiological conditions like strokes and muscle or joint abnormalities. This technique uses the concept of radio frequency emission by a certain nucleus of atoms like hydrogen when placed in an external magnetic field. As hydrogen is abundant in the human body particularly in water and fat, the MRI machine basically maps out the location of water and fat in our body.
This is again an example of an ingenious method designed using principles of physics to probe into the human body and identify abnormalities which are otherwise hard to detect. There are various companies which make medical instruments like Philips which has its own line of healthcare products like CT scanners, MRI machines, X-Ray machines, and tomography machines to name a few.
龚鹏程:您愿意谈谈您在印度的早期生活和在欧洲非常活跃的学术生活吗?您的文化背景(包括积极的和消极的)如何帮助您取得目前的成就?印度和西方的主要文化差异是什么?
尼拉德里·沙克：我在印度一个叫Serampore的历史小镇长大。在学校，我是一个成绩一般的学生，但喜欢科学，尤其是物理。像大多数印度孩子一样，我面对很多父母的压力，他们要求我在学校考试中要表现良好，高中毕业后得去学工程或医学。
在印度，中产阶级家庭总是希望他们的孩子在接受高等教育时做更稳妥的选择，比如选工程或医学领域。像绘画或文学这样的创造性艺术领域通常是不受鼓励和被看不起的，因为它们不太能提供稳定的收入。所以，高中毕业后我准备成为一名工程师，但当时的一些身体状况让我无法参加入学考试，于是我决定攻读物理学学士学位。
我当时并不知道，这个攻读物理学学士的决定有一天会改变我的人生轨迹，点燃我对这门学科更多的热情。在那之后，我又继续攻读了硕士和博士学位，并对在印度以外的地方做博士后研究非常感兴趣。后来，我在欧洲做博士后主要研究软物质和生物物理学。
我发现这里的工作文化和环境与印度学术界截然不同，这里的工作文化和环境主要建立在学生和科学家的热情、诚实和信任之上。在印度，为了接受高等教育而学习科学，与其说是基于学生的真正兴趣，不如说是基于手头能有的选择。在许多情况下，未能通过工程或医学入学考试的学生最终才会在印度学习基础科学。而在欧洲，接受科学高等教育的学生对这门学科有着高度的积极性和热情。
很明显，与我在印度的经历相比，欧洲学生有更严格的职业道德，更有条理。积极地看的话，我想这也影响到了我吧。
I grew up in India in one of the historical towns called Serampore. At school I was a mediocre student but had a liking for science, especially physics. Like most Indian kids, I faced a lot of parental pressure to perform well in the school exams and then go for studying engineering or medicine after my high school.
In India, middle class families always want their kids to go for safe options like engineering or medical fields when it comes to higher studies. Creative art fields like painting or literature are usually discouraged and looked down upon, as they don't always end up providing a steady income job. So, after school I was preparing to become an engineer, but some medical conditions at that time prevented me from appearing for the entrance exams, and that is when I decided to pursue a bachelor’s degree in physics. Little did I know that this decision of going for a Physics BSc would one day change the course of my life and ignite more passion for the subject. I did my master’s and PhD after that and got extremely interested in going for postdoctoral studies outside India. So, I ended up in Europe doing my postdocs in primarily soft matter and biological physics.
What I found quite different here is the work culture and environment which in stark contrast to Indian academia is based largely on the passion, honesty, and trust of students and scientists. In India studying science for higher education is not so much based on the real interest of the students as much as it is based on the options available at hand. In many cases students who fail to clear engineering or medical entrance exams end up studying basic science in India. Whereas in Europe students going for higher education in science are highly motivated and passionate about the subject.
And it has become very evident that European students have a much more disciplined work ethic and are better organized compared to what I experienced in India.On a positive note, I would like to think that has rubbed onto me as well!
龚鹏程：人们想知道物理和文学之间是否现在已有或将来会有重叠？它们之间有一种浪漫的羁绊？您怎么看?
尼拉德里·沙克：在我看来，物理学和文学是非常不同的实体，涉及截然不同的事物。物理学主要是关于了解事物如何工作及其机械特性的事实，而文学主要是虚构和想象。虽然可以根据事实写故事，但这些故事大多被归入自传或历史小说。我认为我们应该庆祝他们的差异，而不是为他们之间缺乏浪漫羁绊而担心。
然而，尽管如此，物理学和文学无法统一也并非完全正确。例如，科幻小说是科学为故事提供素材的文学类型之一。艾萨克·阿西莫夫(Issac Asimov)是使科幻小说流行起来的最多产的科幻作家之一，在全球拥有无数粉丝。
后来也有科幻小说改编成电影的例子，比如《银河系漫游指南》(The Hitchhiker's Guide to The Galaxy)和《火星救援》(The Martian)。更不用说无数的科幻电影，如《星际穿越》或《地心引力》，它们将电影的视觉效果提升到了一个完全不同的水平，并推动了技术的进步。
事实上，著名的天体物理学家基普·索恩(Kip Thorne)曾合作拍摄电影《星际穿越》(Interstellar)，这也为一些科学论文的发表铺平了道路。这是电影和科学携手并进的罕见案例之一。
现在也有基于科幻小说的电视节目。《太空无垠》便是一个很好的例子，在这款游戏中，制作人一直在尝试着从物理角度去完善游戏。
我相信，如果科学和艺术之间的互动能够使双方都受益——无论是相互给予还是互相接受，无论是科学为书籍提供原材料，还是电视节目和电影将科学引向更广泛的受众，那么这都已足够好了。
In my view physics and literature are very different entities and deal with very different things. Physics is mostly about knowing facts about how things work, and their mechanical properties, whereas literature is mostly fiction and imagination. Although one can write stories based on real facts, those are mostly relegated to autobiographies or historical novels. I think we should celebrate their differences and not worry too much about their romance!
However, having said that, it is not entirely true that physics and literature cannot unite. For example, science fiction is one of the genres where science has provided the fodder for the story. Issac Asimov has been one of the most prolific science fiction writers who popularized the genre, and has countless fans spread across the globe.
There had also been instances of science fiction books getting adapted for movies later, like The Hitchhiker's Guide to the Galaxy, and The Martian. And not to mention countless science fiction movies like Interstellar or Gravity which just took visual effects in films to a whole different level and actually played a role in advancing technology.
In fact, one of the famous astrophysicists Kip Thorne collaborated in making the film "Interstellar", which also paved the way for some scientific papers. This was one of the rare instances where film and science actually went hand in hand.
Nowadays there are TV shows also which are based on science fiction. One of the very good examples is The Expanse, where actually the producers have tried to get things right from a physics perspective as much as possible!
I believe that if the interaction between science and art can benefit both sides - either in giving or receiving, either science providing the raw material for books, or tv shows and films bringing science to a wider audience, then that is already good enough.
龚鹏程，1956年生于台北，台湾师范大学博士，当代著名学者和思想家。著作已出版一百五十多本。
办有大学、出版社、杂志社、书院等，并规划城市建设、主题园区等多处。讲学于世界各地。并在北京、上海、杭州、台北、巴黎、日本、澳门等地举办过书法展。现为美国龚鹏程基金会主席。