Archive for Physics

Quantum Technologies at Sussex

Posted in The Universe and Stuff with tags , , , , , on November 26, 2014 by telescoper

Some good news arrived today. We had been hoping to hear it since September but it finally appeared today. It involves several physicists from the Atomic, Molecular and Optical (AMO) Group of the Department of Physics & Astronomy in the School of Mathematical and Physical Sciences here at the University of Sussex who bid to participate in a major investment (of ~£270M) in quantum technology overseen by the Engineering and Physical Sciences Research Council (EPSRC). Today we learned that Sussex physicists were successful in their applications and in fact will participate in two of the four new Quantum Technology “hubs” now being set up. One of the hubs is led by the University of Oxford and the other by the University of Birmingham. We will be starting work on these projects on 1st December 2014 (i.e. next Monday) and the initial funding is for five years. Congratulations to all those involved, not just at Sussex but also in those other institutions participating in the new programme.

For a relatively small Department this is an outstanding achievement for Sussex, and the funding gained will help us enormously with our strategy of expanding laboratory-based experiment physics on the University of Sussex campus. Since I arrived here last year it has been a priority for the School to increase and diversify its research portfolio, both to enhance the range and quality of our research itself and to allow us to teach a wider range of specialist topics at both undergraduate and postgraduate level. This particular subject is also one in which we hope to work closely with local comanies, as quantum technology is likely to be a key area for growth over the next few years.

I’m very excited by all this, because it represents a successful first step towards the ambitious goals the Department has set and it opens up a pathway for further exciting developments I hope to be able to post about very soon.

To celebrate, here’s a gratuitous picture of a laser experiment:

laser

You can find more information about the Quantum Technology hubs altogether here.

The text of the official University of Sussex  press release follows:

Sussex scientists have been awarded £5.5 million to develop devices that could radically change how we measure time, navigate our world and solve seemingly impossible mathematical equations.

The grants, received by members of the University’s Atomic, Molecular and Optical Physics (AMO) research group, represent part of a £270 million UK government investment announced today (26 November) to convert quantum physics research into commercial products.

Quantum technology is the applied field of quantum theory. It includes such phenomena as “quantum entanglement”, the idea that objects are not independent if they have interacted with each other or come into being through the same process, and that changing one will also change the other, no matter how far apart they are.

Members of the AMO group have become part of two major national quantum centres: the UK Quantum Technology Hub on Networked Quantum Information Technologies and the UK Quantum Technology Hub for Sensors and Metrology. These centres bring together universities and industry to develop and construct quantum technologies.

The award from the Engineering and Physical Sciences Research Council (EPSRC) will help to fund several Sussex research projects:

  • Dr Jacob Dunningham will be developing a theory to understand how remote objects can be detected with exquisite precision by making use of a networks of sensors linked by quantum entanglement.
  • Dr Winfried Hensinger, as part of one hub, will develop the quantum processor microchip architecture and a new technique of quantum processing using microwave radiation to enable the construction of a large-scale “super-fast” quantum computer. As part of the other hub, he will develop powerful portable sensors able to detect magnetic fields with unprecedented accuracy utilizing a new generation of microchips capable of holding arrays of individual charged atoms.
  • Dr Alessia Pasquazi will develop miniature, ultra-fast, photonic sources of light that form the heart of a new generation of quantum sensors and navigation devices.
  • Dr Marco Peccianti will shrink to the size of a shoe box an “optical frequency comb”, a highly accurate clock currently found only in state-of-the-art laboratories.
  • Prof Barry Garraway will design new rotation sensors for compact navigation devices using atom-chip technology.
  • Dr Matthias Keller will develop a network connecting several quantum processors through the exchange of single photons, resulting in a new version of the internet, the so-called ‘quantum internet’.

In response to the funding news, Professor Peter Coles, Head of the School of Mathematics and Physical Sciences, said: “Quantum sensors offer amazing possibilities for smaller and lighter devices with extraordinary precision. As a consequence, quantum theory promises revolutionary technological applications in computing, measurement, navigation, and security.”

Professor Michael Davies, Pro-Vice-Chancellor for Research, said: “This new research programme will consolidate the reputation of the University of Sussex as one of the world-leading centres for the development of ground-breaking quantum technologies.”

The research will be supplemented by a significant Sussex investment and will make use of the world-leading multi-million pound quantum technology laboratories located at the University.

Professor Coles added: “Our pioneering ‘MSc in Frontiers of Quantum Technology’ program along with numerous PhD positions will provide training for a new generation of researchers and developers to be employed in the emerging quantum technology sector.”

Greg Clark, Minister of State for Universities, Science and Cities, said: “This exciting new Quantum Hubs network will push the boundaries of knowledge and exploit new technologies, to the benefit of healthcare, communications and security.

“Today’s announcement is another example of the government’s recognition of the UK’s science base and its critical contribution to our sustained economic growth”.

The Physics Of Nonconformity: Why Difference Always Looks The Same

Posted in Beards, The Universe and Stuff with tags , , , , on November 17, 2014 by telescoper

I came across an interesting paper while I was in an unblogging state last week so thought I’d share it here. Have you ever wondered why non-conformists always seem to look the same? I was struck by this last year when I saw a group of self-styled “anarchists” – of which there are many in Brighton – gathering ahead of a demonstration against something or other, or possibly nothing at all. Anyway they all struck rigidly to a particular dress code, a fact which I found amusing given their professed preference for a state of disorder. The same seems to be the case in other contexts too. A striking current example is  the fad for the “hipster” beard, but wherever you look you will find a group of people who express their desire to be different by looking exactly the same as each other.  It seems people always want to conform in some way. Perhaps we should call this conformal invariance?

Anyway, the paper investigates this – in a slightly tonggue-in-cheek manner – from the point of view of statistical physics using an approach similar to that used to study the phenomenon of the spin glass. Here is the abstract:

In such different domains as statistical physics and spin glasses, neurosciences, social science, economics and finance, large ensemble of interacting individuals taking their decisions either in accordance (mainstream) or against (hipsters) the majority are ubiquitous. Yet, trying hard to be different often ends up in hipsters consistently taking the same decisions, in other words all looking alike. We resolve this apparent paradox studying a canonical model of statistical physics, enriched by incorporating the delays necessary for information to be communicated. We show a generic phase transition in the system: when hipsters are too slow in detecting the trends, they will keep making the same choices and therefore remain correlated as time goes by, while their trend evolves in time as a periodic function. This is true as long as the majority of the population is made of hipsters. Otherwise, hipsters will be, again, largely aligned, towards a constant direction which is imposed by the mainstream choices. Beyond the choice of the best suit to wear this winter, this study may have important implications in understanding dynamics of inhibitory networks of the brain or investment strategies finance, or the understanding of emergent dynamics in social science, domains in which delays of communication and the geometry of the systems are prominent.

Comments through the usual channel please!

 

 

Science, Poetry and Romanticism

Posted in Poetry, The Universe and Stuff with tags , , , , , , on November 4, 2014 by telescoper

I listened to a very interesting programme on BBC Radio 3 on Sunday evening, part of which was a documentary about science and poetry presented by Gregory Tate. Given that both these subjects feature heavily on this blog I couldn’t resist a quick post about it.

The feature explored why so many scientists have been inspired to write poetry, and the nature of the relationship between their artistic work and their science.

Among the famous scientists included in the programme was chemist and inventor Humphry Davy who, inspired by his friendship with the poets Wordsworth and Coleridge, wrote poems throughout his life. Others to do likewise were: physician Eramus Darwin; mathematician William Rowan Hamilton; astronomer William Herschel (who was also a noted musician and composer); J. Robert Oppenheimer; and Erwin Schrödinger.

Doing a quick google about after the programme I came across this example by Hamilton, which I searched for because he is the scientist from the list above with whose mathematical work I am most familiar because of its huge influence on physics, and because he seems to have been a very colourful character as well as a superb mathematician. Interestingly, he too was a very close friend of Wordsworth, to whom he often sent poems with requests for comments and feedback. In the subsequent correspondence, Wordsworth was usually not very complimentary even to the extent of telling Hamilton to stick to his day job (or words to that effect). What I didn’t know was that Hamilton regarded himself as a poet first and a mathematician second. That just goes to show you shouldn’t necessarily trust a man’s judgement when he applies it to himself.

Here’s an example of Hamilton’s verse – a poem written to honour Joseph Fourier:

Hamilton-for Fourier

If that’s one of his better poems, then I think Wordsworth may have had a point!

The serious thing that struck me about this programme though was how many scientists of the 19th Century, Hamilton included, saw their scientific interrogation of Nature as a manifestation of the human condition just as the romantic poets saw their artistic contemplation. It is often argued that romanticism is responsible for the rise of antiscience. I’m not really qualified to comment on that but I don’t see any conflict at all between science and romanticism. I certainly don’t see Wordsworth’s poetry as antiscientific. I just find it inspirational:

I HAVE seen
A curious child, who dwelt upon a tract
Of inland ground, applying to his ear
The convolutions of a smooth-lipped shell;
To which, in silence hushed, his very soul
Listened intensely; and his countenance soon
Brightened with joy; for from within were heard
Murmurings, whereby the monitor expressed
Mysterious union with its native sea.
Even such a shell the universe itself
Is to the ear of Faith; and there are times,
I doubt not, when to you it doth impart
Authentic tidings of invisible things;
Of ebb and flow, and ever-during power;
And central peace, subsisting at the heart
Of endless agitation.

Working for Different Masters

Posted in Education with tags , , , , , , , on November 1, 2014 by telescoper

Quite a few times recently, current and prospective students (or parents thereof) have asked me what the difference is between the different forms of Masters degrees that you can get in the United Kingdom, chiefly the distinction between an MSc  and one of the variations on the MPhys or MMath we have here in the School of Mathematical and Physical Sciences here at the University of Sussex. I have to admit that it’s all very confusing so here’s my attempt to explain.

The main distinction is that the MSc “Master of Science” is a (taught) postgraduate (PG) degree, usually of one (calendar) year’s duration, whereas the MPhys etc are undergraduate (UG) degrees usually lasting 4 years. This means that students wanting to do an MSc must already have completed a degree programme (and usually have been awarded at least Second Class Honours)  before starting an MSc whereas those doing the MPhys do not.

Undergraduate students wanting to do Physics in the Department of Physics & Astronomy at the University of Sussex, for example, can opt for either the 3-year BSc or the 4-year MPhys programmes. However, choosing the 4-year option does not lead to the award of a BSc degree and then a subsequent Masters qualification;  graduating students get a single qualification usually termed an “integrated Masters”.

It is possible for a student to take a BSc and then do a taught MSc programme afterwards, perhaps at a different university, but there are relatively few MSC programmes for Physics  in the UK because the vast majority of students who are interested in postgraduate study will already have registered for 4-year undergraduate programmes. That’s not to say there are none, however. There are notable MSc programmes dotted around, but they tend to be rather specialist; examples related to my own area include Astronomy and Cosmology at Sussex and Astrophysics at Queen Mary.  To a large extent these courses survive by recruiting students from outside the UK because the market from home students is so small. No department can afford to put on an entire MSc programme for the benefit of just one or two students. Often these stand-alone courses share modules with the final year of the undergraduate Masters, which also helps keep them afloat.

So why does it matter whether one Masters is PG while the other is UG? One difference is that the MSc lasts a calendar year (rather than an academic year). In terms of material covered, this means it contains 180 credits compared to the 120 credits of an undergraduate programme. Typically the MSc will have 120 credits of courses, examined in June as with UG programmes, followed by 60 credits worth of project work over the summer, handed in in September, though at Sussex some of our programmes are split 90 credits coursework and 90 credits of project.

The reason why this question comes up so frequently nowadays is that the current generation of applicants to university (and their parents) are facing up to fees of £9K per annum. The cost of doing a 3-year BSc is then about £27K compared to £36K for an MPhys. When rushing through the legislation to allow universities to charge this amount, the Powers That Be completely forgot about PG programmes, which have accordingly maintained their fees at a similar level. For example, the MSc Astronomy at Sussex attracts a fee of about £5K for home students and about £15K for overseas students. These levels are roughly consistent with the UG fees paid by  home students on the previous fee regime (approx £3.5K per annum, bearing in mind that you get 1.5 times as much teaching on an MSc compared to a year of an MPhys).

Being intelligent people, prospective physicists look at the extra £9K they have to pay for the 4th year of an MPhys and compare it with the current rate for an entire MSc and come to the conclusion that they should just do a BSc then switch. This seems to be not an unreasonable calculation to make.

However, there are some important things to bear in mind. Firstly, unlike UG programmes, the fee for PG programmes is basically unregulated. Universities can charge whatever they like and can increase them in the future if they decide to. See, for example, the list at Sussex University which shows that MSc fees already vary by more than a factor of four from one school to another. Incidentally, that in itself shows the absurdity of charging the same fee for UG degrees regardless of subject…

Now the point is that if one academic year of UG teaching is going to cost £9K for future students, there is no way any department can justify putting on an entire calendar of advanced courses (i.e. 50% more teaching at an extremely specialist level) for less than half the  income per student. The logical fee level for MSc programmes must rise to a mininum of about 1.5 times the UG fee, which is a whopping £13.5K (similar to the current whopping amount already paid by overseas students for these programmes). It’s therefore clear that you cannot take the current MSc fee levels as a guide to what they will be in three years’ time, when you will qualify to enter a taught PG programme. Prices will certainly have risen by then.

Moreover, it’s much harder to get financial support for postgraduate than undergraduate study.  MSc students do not qualify for student loans as undergraduates do, for example. Also the MSc fee usually has to be paid in full, up front, not collected later when your income exceeds some level. Some PG courses do run their own bursary schemes, such as many of those at Sussex, for example, but generally speaking students on taught PG programmes have to find their own funding. On the other hand,  undergraduate students often qualify for generous packages, including fee waivers and reduction in accommodation, especially if they qualify for support for widening participation, such as the “First Generation Scholar” scheme at Sussex.

I’d say that, contrary to what many people seem to think,  if you take into the full up-front fee and the lack of student loans etc, the cost of a BSc + MSc is  already significantly greater than doing an MPhys, and in future the cost of the former route will inevitably increase. I therefore don’t think this is a sensible path for most Physics undergraduates to take, assuming that they want their MSc to qualify them for a career in Physics research, either in a university or a commercial organization, perhaps via the PhD degree, and they’re not so immensely rich that money is no consideration.

The exception to this conclusion is for the student who wishes to switch to another field at Masters level,  to do a specialist MSc in a more applied discipline such as medical physics or engineering. Then it might make sense, as long as you can find a way to deal with the need to pay up-front for such courses.

There are indications that the government might be planning to introduce student loans for postgraduate degrees similar to those currently offered for undergraduates, but for me that would only make sense if the fees were to increase as described above, so this would not be an entirely positive move (to say the least).

In conclusion, though, I have to say that, like many other aspects of Higher Education in the Disunited Kingdom, this system is a mess. I’d prefer to see the unified system of 3 year UG Bachelor degrees, 2-year Masters, and 3-year PhD that pertains throughout most of continental Europe. To colleagues there, the system of two types of Masters degree looks like a complete mess.  Which it is. In fact some countries do not accept out integrated Masters as preparation for a PhD at all.

P.S. In the interest of full disclosure, I should point out an even worse anomaly. I did a 3-year Honours degree in Natural Science at Cambridge University for which I was awarded not a BSc but a BA (Bachelor of Arts). A year or so later this – miraculously and with no effort on my part – turned into an MA. Work that one out if you can.

Controlled Nuclear Fusion: Forget about it

Posted in The Universe and Stuff with tags , , , on October 20, 2014 by telescoper

telescoper:

You’ve probably heard that Lockheed Martin has generated a lot of excitement with a recent announcement about a “breakthrough” in nuclear fusion technology. Here’s a pessimistic post from last year. I wonder if it will be proved wrong?

Originally posted on Protons for Breakfast Blog:

Man or woman doing a technical thing with a thingy told with laser induced nuclear fusion.

Man or woman adjusting the ‘target positioner’ (I think) within the target chamber of the US Lawrence Livermore National Laboratory.

The future is very difficult to predict. But I am prepared to put on record my belief that controlled nuclear fusion as a source of power on Earth will never be achieved.

This is not something I want to believe. And the intermittent drip of news stories about ‘progress‘ and ‘breakthroughs‘ might make one think that the technique would eventually yield to humanity’s collective ingenuity.

But  in fact that just isn’t going to happen. Let me explain just some of the problems and you can judge for yourself whether you think it will ever work.

One option for controlled fusion is called Inertial Fusion Energy, and the centre of research is the US National Ignition Facility. Here the most powerful laser…

View original 601 more words

A Problem of Wires on the Rails

Posted in Cute Problems with tags , , , on October 5, 2014 by telescoper

It’s been a long time since I posted a cute physics problem so here’s one about magnetism for your edification and/or amusement.

Two long wires are laid flat on a pair of parallel rails perpendicular to the wires. The spacing d between the rails is large compared with x, the distance between the wires. Both wires and rails are made of material which has a resistance ρ per unit length. A magnetic flux density B is applied perpendicular to the rectangle formed by the rails and the wires. One wire is moved along the rails with uniform speed v while the other is held stationary. Derive a formula to show how the force on the stationary wire varies with x and use it to show that the force vanishes for a value of x approximately equal to μ0v/4πρ.

Give a physical interpretation of this result.

HINT: Think about the current induced in the wires…

 

Newcastle Joins the Resurgence of UK Physics

Posted in Education, Science Politics, The Universe and Stuff with tags , , , on August 17, 2014 by telescoper

I’ve posted a couple of times about how Physics seems to undergoing a considerable resurgence in popularity at undergraduate level across the United Kingdom, with e.g. Lincoln University setting up a new programme. Now there’s further evidence in that Newcastle University has now decided to re-open its Physics course for 2015 entry.

The University of Newcastle had an undergraduate course in Physics until 2004 when it decided to close it down, apparently owing to lack of demand. They did carry on doing some physics research (in nanoscience, biophysics, optics and astronomy) but not within a standalone physics department. The mid-2000s were tough for UK physics,  and many departments were on the brink at that time. Reading, for example, closed its Physics department in 2006; there is talk that they might be starting again too.

The background to the Newcastle decision is that admissions to physics departments across the country are growing at a healthy rate, a fact that could not have been imagined just ten years ago. Times were tough here at Sussex until relatively recently, but now we’re expanding on the back of increased student numbers and research successes. Indeed having just been through a very busy clearing and confirmation period at Sussex University, it is notable that its the science Schools that have generally done best.  Sussex has traditionally been viewed as basically a Liberal Arts College with some science departments; over 70% of the students here at present are not studying science subjects. With Mathematics this year overtaking English as the most popular A-level choice, this may well change the complexion of Sussex University relatively rapidly.

I’ve always felt that it’s a scandal that there are only around 40 UK “universities” with physics departments Call me old-fashioned, but I think a university without a physics department is not a university at all; it’s particularly strange that a Russell Group university such as Newcastle should not offer a physics degree. I believe in the value of physics for its own sake as well as for the numerous wider benefits it offers society in terms of new technologies and skills. Although the opening of a new physics department will create more competition for the rest of us, I think it’s a very good thing for the subject and for the Higher Education sector general.

That said, it won’t be an easy task to restart an undergraduate physics programme in Newcastle, especially if it is intended to have as large an intake as most successful existing departments (i.e. well over 100 each year). Students will be applying in late 2014 or early 2015 for entry in September 2015. The problem is that the new course won’t figure in any of the league tables on which most potential students based their choice of university. They won’t have an NSS score either. Also their courses  will probably need some time before it can be accredited by the Institute of Physics (as most UK physics courses are).

There’s a lot of ground to make up, and my guess is that it will take some years to built up a significant intake.The University bosses will therefore have to be patient and be prepared to invest heavily in this initiative until it can break even. The decision a decade ago to cut physics doesn’t exactly inspire confidence that they will be prepared to do this, but times have changed and so have the people at the helm so maybe that’s an unfair comment.

There are also difficulties on the research side (which is also vital for a proper undergraduate teaching programme), there are also difficulties. Grant funding is already spread very thin, and there is little sign of any improvement for the foreseeable future  in the “flat cash” situation we’re currently in. There’s also the stifling effect of theResearch Excellence Framework I’ve blogged about before. I don’t know whether Newcastle University intends to expand its staff numbers in Physics or just to rearrange existing staff into a new department, but if they do the former they will have to succeed against well-established competitors in an increasingly tight funding regime. A great deal of thought will have to go into deciding which areas of research to develop, especially as their main regional competitor, Durham University, is very strong in physics.

On the other hand, there are some positives, not least of which is that Newcastle is and has always been a very popular city for students (being of course the finest city in the whole world). These days funding follows students, so that could be a very powerful card if played wisely.

Anyway, these are all problems for other people to deal with. What I really wanted to do was to wish this new venture well and to congratulate Newcastle on rejoining the ranks of proper universities (i.e. ones with physics departments). Any others thinking of joining the club?

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