In physics we do things and afterwards worry about whether they worked
October 2, 2010Posted by on
As I am being educated in the UK and intend to attend university here, I am becoming increasingly appalled by the treatment of science we are seeing. Science funding has been under severe pressure for the last several years, first under the previous Labour government, and now, along with so much else, under the Coalition which is planning excruciatingly severe cuts .
Science is crucial to the economic and social future of the UK. It would be devastating for the UK to give up its position as almost certainly the second most powerful country in the world, after only the USA, in higher education and scientific research. Even today (again, after several years of cuts to grants in the physical sciences), the vast majority (over 90%) of research funding goes to world-class scientists, as judged by the latest Research Assessment Exercise. It is impossible to cut this without reducing the amount of excellent research produced in the UK. Moreover, threats of such cuts are already making scientists consider their options — most other countries are increasing, rather than decreasing, their science budgets not despite but because of the economic downturn and growing deficits.
The evidence is clear that investing in research brings a range of economic and social benefits, and that severe cuts at the very moment that our competitor nations are investing more could jeopardize the future of UK science.
For the few reader of this blog, I would like to point out the concerted effort to push back against the planned short-sighted cuts, under the banner of the Science is Vital campaign.
From their website, Science is Vital is
… a group of concerned scientists, engineers and supporters of science who are campaigning to prevent destructive levels of cuts to science funding in the UK.
and the concrete steps that one can take to help the cause (mostly useful if you live in Britain) are
1. Sign the Campaign for Science & Engineering petition.
2. Join the Science is Vital demo in central London, Saturday 9th October at 2 PM.
3. Write to your MP about the importance of science, technology, engineering and maths.
4. Come to the Houses of Parliament for the Science is Vital lobby of MPs on 12th October, 3.30 to 4.30 PM.
5. Spread the word using the posters.
I would urge you to sign the ScienceIsVital petition. It is the least we can do to help maintain Britain’s historic strength in the area. For reasons that are both personal (I will be attending a university affected by these cuts) and intellectual, I am hoping that the scale of these cuts will be less than is currently planned. because . With scientists being very much “footloose” and other countries increasing their science funding this will inevitably mean that the UK will lose much of its research excellence is the legacy of many generations.
September 13, 2010Posted by on
In 1900, David Hilbert published his list of 24 problems that he believed would be part of the development of mathematics in 20th century – and so they were! The closest we come to a 21st century analogue of these are the Clay Institute Millenium Prizes, and Steve Smale’s problems (though these have not, sadly, become as widely known as the others). Certainly anyone involved in mathematics research is aware of most, if not all of these problems.
Until today, the only physics counterpart to these that I was aware of was Wikipedia’s List of unsolved problems in physics – which is reasonably comprehensive and has drawn my attention to some interesting unexplained phenomena in CMP (ever heard of sonoluminescence?). However, just now I’ve come across a list by a Russian physicist Vitaly L. Ginzburg. It’s a list of thirty problems that Ginzburg thinks every physicist should know about.
As far as I know, the list first appeared in his 2003 Nobel Lecture. The paper may be found here, but I’ll reproduce the list below anyway:
- Controlled nuclear fusion
- High-temperature and room temperature superconductivity.
- Metallic hydroge. Other exotic substances.
- Two-dimensional electron liquid (the anomalous Hall effect and other effects).
- Some questions of solid-state physics (heterostructures in semiconductors, quantum wells and dots, metal-dielectric transitions, charge- and spind-density waves, mesoscopics).
- Second-order and related phase transitions. Some examples of such transtitions. Cooling, in particular laser cooling, to superlow temperatures. Bose-Einstein condensation in gases.
- Surface physics. Clusters.
- Liquid crystals. Ferroelectrics. Ferrotorics.
- Fullerenes. Nanotubes.
- The bahaviour of matter in superstrong magnetic fields.
- Nonlinear physics. Turbulence. Solitons. Chaos. Strange attractors.
- X-ray lasers, gamma-ray lasers, superhigh-power lasers.
- Superheavy elements. Exotic nuclei.
- Mass specturm. Quars and gluons. Quantum chromodynamics. Quark-gluon plasma.
- Unified theory of weak and electromagnetic interactions. and bosons. Leptons.
- Standard model. Grand unification. Superunification. Proton decay. Neutrino mass. Magnetic monopoles.
- Fundamental length. Particle interaction at high and superhigh energies. Colliders.
- Non-conservation of CP invariance.
- Nonliear phenomena in vacuum and in superstrong magnetic fields. Phase transitions in a vacuum.
- Strings. M-theory.
- Experimental verification of the general theory of relativity. [You might like to take a look at this.]
- Gravitational wanes and their detection.
- The cosmological problem. Inflation. The term and quintessence. Relationship between cosmologyand high-energy physics.
- Neutron starts and pulsars. Supernova stars.
- Black holes. Cosmic strings (?).
- Quasars and galactic nuclei. Formation of galaxies.
- The problem of dark matter (hidden mass) and its detection.
- The origin of superhigh-energy cosmic rays.
- Gamma-ray bursts. Hypernovae.
- Neutrino physics and astronomy. Neutrino oscillations.
Ginzburg also says that:
It should be added that three “great problems” of modern physics are also to be included in the “physics minimum,” included in the sense that they should be singled out in some way and specially discussed, and their development should be reviewed. This is discussed at some length in the book About Science, Myself, and Others (Ginzburg, 2003). The “great problems” are, ﬁrst, the increase in entropy, time irreversibility, and the “time arrow.” Second is the problem of interpretation of nonrelativistic quantum mechanics and the possibility of learning something new even in the ﬁeld of its applicability. I personally doubt this possibility but believe that one’s eyes should remain open. And third is the question of the emergence of life, i.e., the feasibility of explaining the origin of life and thought on the basis of physics alone. On the face of it, how could it be otherwise? But until the questions are elucidated, one cannot be quite sure of anything. I think that the problem of the origin of life will unreservedly be solved only after “life in a test-tube” is created. Until then, this will be an open question.
Ginzburg sadly passed away on November 8th, 2009. Among his achievements are a partially phenomenological theory of superconductivity, the Ginzburg-Landau theory, developed with Landau in 1950; the theory of electromagnetic wave propagation in plasmas (for example, in the ionosphere); and a theory of the origin of cosmic radiation. He was beyond a doubt a great physicst, and maybe one day his list will be counted among his greatest achievements. It might steer the progress of physics in the coming years -we’ll see.
Finally this last quote from Ginzburg’s paper:
One more concluding remark. In the past century, and even nowadays, one could encounter the opinion that in physics nearly everything had been done. There allegedly are only dim “cloudlets” in the sky or theory, which will soon be eliminated to give rise to the “theory of everything.” I consider these views as some kind of blindness. The entire history of physics, as well as the state of present-day physics and, in particular, astrophysics, testiﬁes to the opposite. In my view we are facing a boundless sea of unresolved problems.
It only remains for me to envy the younger members of the audience, who will witness a great many new, important, and interesting things.
September 7, 2010Posted by on
I’ve just spent quite a bit of time digging around to find a way to type up some chemistry in LaTeX. For those of you in the same situation, I would suggest following a series of three posts over at Toeholds:
The chemistry side of this blog will kick off soon – I’m interested in certain parts of chemistry, as you will see. First up: combinatorial chemistry.
August 28, 2010Posted by on
According to Wikipedia, quantum metrology is the study of making high-resolution and highly sensitive measurements of physical parameters using quantum theory to describe the physical systems, in particular exploiting quantum entanglement.
If you are interested, you might want to take a look at this. It is a paper entitled Ensemble based quantum metrology. Quoting the abstract:
We consider measurement of magnetic field strength using an ensemble of spins, and we identify a third essential resource: the initial system polarisation, i.e. the low entropy of the original state. We find that performance depends crucially on the form of decoherence present; for a plausible dephasing model, we describe a quantum strategy which can indeed beat the standard quantum limit.
August 19, 2010Posted by on
Feynman’s path integral formulation is important in quantum physics. Some people learn it when they come to do Quantum field theory where it plays a central role. However, there is a book that introduces a sophisticated physics student with reasonable background to path integral in non-relativistic quantum mechanics, “Quantum mechanics and path integrals”, by Feynman and Hibbs.
It is highly recommended. It is a book full of deep and extraordinary insights, as one expects from Feynman. It is not a standalone textbook in QM – it should be used in conjunction with a conventional text.
What I love the most about this book is how quickly the laws of physics are laid out – by the end of chapter 2 they are in place, and the rest of the book is applications. It is an approach similar to the one he adopts in Vol. 2 of Feynman Lectures on Physics where Maxwell’s equations are laid before you in their finished form in the first chapter and the rest of the book is devoted to understanding those equations.
The original edition, 1967, was riddled with errors. The new one is amended and available on Amazon at the end of September this year, and being a Dover costs an agreeable £15. Should you happen to come across the first edition, Daniel Styer’s errata is an absolute must. It is available here.
August 19, 2010Posted by on
I would like to pay tribute to the great physicist, Nicola Cabibbo who died on Monday at the age of 75.
He was mainly known for his work on weak interactions. He explained why the transitions between up and down quarks, electrons and electron neutrinos, muons and muon neutrinos had similar quantum amplitudes by postulating weak universality. He also explained why transitions with a change in strangeness had about a quarter the amplitude of those with no change in strangeness through the mixing angle (also called Cabibbo angle).