IAS Distinguished Lecture Series: The Future of Physics

The speaker of the talk is Prof. David Gross, Nobel Laureate of Physics in 2004. Prof. Gross discuss about 25 questions that might guide Physics in the next 25 years. The questions range from cosmology to Biophysics.

The talk was held at LT-K, which is actually a small room for lecture. Due to presence of a distinguished speaker, LT-K was actually fully occupied and some audience needed to sit (on the ground) just in front of the screen, which of course is not a desired place to listen the talk. Later the talk was relocated to LT-D, again, fully occupied.

Well, the first question came: What is Physics? Of course, one could give the "official" answer yet it would be instructive to start the talk with something different. Physics is what physicists do. Here we have to define "physicists". They are (we are?) those people, while studying graduate school, use Jackson as EM textbook! To understand this joke, you ought to be within the Physics community. Why defining like this? Prof. Gross said that he wants to distinguish physicists from engineers. That's true. The math in Jackson's EM text is really too arduous for most of the engineers.

Below is the list of most of the questions mentioned in the talk, however, I think this list is incomplete. Anyway, for those who study Physics (including me), this list might be helpful.

• How did the universe begin?
• How far can we probe?
• Can string theory determine initial conditions?
• Was there a time before the big bang?
• Is time itself an emergent concept?
• How does time begin?
• What is the nature of dark matters (~21%)?
• How do we detect dark matter?
• Can we produce them in the laboratory?
• What is the nature of dark energy (~75%)?
• Is it constant or varying in time?
• Or is it just the Einstein's cosmological constant, Λ?
• How do stars form?
• How do we understand spectrum of masses, frequency of binaries and clusters?
• How do planets form?
• What is the frequency of habitable planets?
• Is General Relativity valid in all scales?
• Would it breakdown at small distance and/or strong field?
• Is gravitational waves detectable?
• Can we determine Kerr Metric of a blackhole experimentally?
• Is quantum mechanics the ultimate description of nature or will it fail somewhere?
• Fail at very short distances? (Resolved by string theory)
• Fail in large complex systems? (the Schrodinger's cat)
• Problems with conscious systems (problems of measurements)
• Problems with Standard Model
• Is there any pattern for the masses and interaction coefficients of the elementary particles?
• Does quantum fluctuation give rise to an energy (= cosmology constant)?
• Λ_obs ~ 10^-4eV⁴ ≠ 0
• Λ_theory ~ 10⁶⁰eV⁴
• Why is there such a large inconsistency between the observed and theoretical values?
  
• Are diamonds forever? (Is nucleus stable?) Why?
• Proton's lifetime > 10³² years. Why is it so stable?
• Can we significantly improve this measurement?
• What is the origin of the enormous hierarchy of energy scales?
• The scale (length, energy & time) of our living universe differs a lot from the natural scale (Planck scale)
• Is there low energy supersymmetry?
• Due to supersymmetry, there is a super-partner (super-particle) for each observed particle, e.g. quark → squark; electron → slectron
• These super-particles are supposed to have the same masses as the partners. But we actually can't observe them, why is there a broken symmetry?
• Can we solve quantum chromodynamics at long distance?
• Possibly by dual string theory
• What is string theory?
• Actually string theory cannot be solved in approximative way. Yet now we cannot solve it in an exact manner.
• What is space-time?
• Is space-time an emergent concept?
• Are there generic non-Fermi-liquid?
• For quantum computers, how can we deal with the background noise?
• In an quiet way - isolated from the noise
• In an deaf way - "topological" quantum bits that are delocalized and that are totally decoupled from the noise
• Can we construct an applicable quantum computer? (we need >10,000 QuBits)
• Is there room temperature (or even higher temperature) superconductor?
• Is there room temperature ferromagnet made by electronic (semiconductors) materials?
• Theoretical Biology Problem
• How to we think of analyze and exhibit dynamics over many wide-ranging time scales?
• Genomics
• Can theory of evolution be quantitative or predictive?
  For example, there may be a genomics question like this in the year of 2107:
  What is the outlook of the creature that have the DNA sequence of AAAGTCTGAC...... > Answer <
• What is consciousness and/or memory?
• Can one measure the onset of consciousness in infant? For instance, consciousness increases continuously with age? Or discontinuously?
• Computational Physics
• Will computer replace analytic techniques?
• When will we have creative theoretical physicists of computers?
• How do we train them? (With Jackson?)
• In high energy Physics, will the experimental apparatus become unaffordable or too difficult to be built?
• Can we find any alternative ways to prove/disprove the theories?
  
• Will Physics be a useful subject in the next 25 years? (Yes, for sure)
  

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Prof. Gross is specialized in high energy Physics, so inevitably the content of the talk had to have some bias towards those area, such as string theory and standard model etc.

In my view, most of the questions related to high energy Physics can't be resolved in a short time. Physicists still have to work really hard.

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逛高登

我想熟識電腦的人都應該知道黃金與高登這個地方。這座專門作為電腦電玩的商場，是很多電玩電腦發燒友其中一個必到之地（其餘的是旺角和灣仔的電腦商場）。也許很多人都知道其實黃金與高登其實是屬於不同的戶主的，而且他們並不相連。

我很久都沒有碰過電腦的相關知識，可以說是非常 Out-dated。我的電腦只有 512MB RAM, 相對現在標準的 1GB，足足差一倍。而且我也覺得現在的電腦好像「神神哋」，打算在不久的將來買台新的，所以便去高登逛逛，看看最新的 Config (Configuration)，而且買了本電腦雜誌，了解一下最新的資訊，同時也上網找找資料。

先說說黃金與高登吧。原來高登（即大廈的上層）開了新翼。新翼其實並不「新」了，但好像是最近才將新翼連到舊翼吧！我想很多人都未發現這個相連的新翼，因為實在太不顯眼了，除非人們走進那把新舊翼相連的「通道」吧。其實那是一店舖，新翼未開之前，那通道是死胡同，而胡同的兩旁是同一間電腦商店，除非人們去那裡買東西吧，不然很少會進入那死胡同的。也因為如此，到現在也很少人到新翼去吧！

逛高登當然就會看電腦零件與其價錢的啦。我發覺現在的零件的散熱器愈來愈大，有的比那零件還大，真的很誇張。現在，電腦零件發放的熱量真是驚人。這也是沒辦法的。如果可以發明到熱量發放較少的代替品，那未嘗不會是一件好事。

現在的 CPU 原來已經是四核心的了。上網查資料才知道什麼是多核心 CPU。其實並不是愈多核心愈好，如果編碼不支援多核心，再多核心也不會用到，也等於浪費。另外，CPU 也由 32-bit 增加至 64-bit，用以支援大於 4GB 的 RAM。64-bit CPU 剛出台的時候，是一定要用相應的 OS (Operation System) 的，不過現在好像是在 CPU 裡設定了什麼，32 bit 的 OS 也可以驅動 64-bit 的 CPU。

電腦的發展真是很快，幾年的光景已經有很多技術的改良或進步，使電腦的速度愈來愈快。不過現在我覺得 CPU 的速度好像到了一個樽頸位，要靠多核心的技術才能使速度有所提升。看來下一個技術的突破會是新 CPU 的發明，可能會是量子電腦。真是期待下個電腦世紀的來臨！

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