The May 2009 research newsletter
Editorial
Welcome to the May 2009 research newsletter. The academic year comes to an end with more good news: £1.8M worth of new grants, a new book out by a member of the department, a prestigious Leverhulme Fellowship awarded to one of our graduate students and more. Hope you all have a productive and happy summer!
[KW, JJ]
New biomolecule insights with ultrafast 2D-IR
Over the course of the last decade, ultrafast 2D-IR spectroscopy has emerged as a powerful new probe of the structure-function relationships of proteins and enzymes. The combination of femtosecond time resolution and atomic-level structural information mean that it is possible to observe the rapid fluctuations and interactions with water that play an important role in protein folding as well as offering the possibility to observe reactions and conformational changes in real time.
While popular in the USA and Europe, this technique is only slowly emerging in the UK with only two groups currently actively engaged in 2D-IR research. More information can be found in a recent invited Tutorial Review article in Chemical Society Reviews, which will be featured in the cover of the journal.
[NTH]
The arrow of time
Why do we remember the past and not the future? Why does cause precede effect? No law of physics has been shown to contain an intrinsic time direction, so searches for an arrow of time have concentrated on asymmetry based on boundary conditions. A simple example is the second law of thermodynamics, which in pure form treats the future and the past equally. Given only the knowledge of a system now, its entropy increases towards the future and the past. The asymmetry in this law that we observe is thought to come from the extremely smooth state of the early universe, a very low entropy state. This boundary condition provides a direction for the second law.
Quantum mechanics appears to be a fundamental theory, and so there have been attempts to link the arrow of time to it. Time evolution in quantum theory has no intrinsic direction, so if any hidden arrow exists it must lie in the other, mysterious part - measurement. A recent paper by John Jeffers (Phys. Lett. A, 373, 1911, 2009.) looks at open quantum systems - those which interact with their surroundings. Such systems are thought of as undergoing almost-continuous weak measurements by their environment.
Every time a measurement is made a boundary condition is imposed on the quantum system. This boundary condition has two properties. Firstly it stops the measurement from influencing the previously prepared state (no backwards causation), and secondly it manufactures a new state of the system, which can be measured later. The main point is that in continuously measured systems the "no backwards causation" property is continuously imposed on the system, leading to a measurement boundary condition-based arrow of time for open quantum systems.
The state prepared by the first measurement influences the second one, but the second measurement cannot influence the prepared state.
Rapid weaker measurements imposed on open systems continuously apply the measurement boundary condition, giving evolution a time direction.
[JJ]
Corresponding Fellow RSE
Prof Padma Shukla was admitted on 11 May 2009 as one of the five Corresponding Fellows of the Royal Society of Edinburgh, elected in 2009.
Professor Padma Kant SHUKLA, Professor at the Faculty of
Physics of Astronomy, Ruhr University Bochum, Germany;
Visiting Professor at SUPA, Department of Physics,
University of Strathclyde.
In the picture Professor Shukla is seen being welcomed as a Corresponding Fellow by the RSE President, Lord Wilson of Tillyorn.
Gravitational Research: LIGO Physical Review Letter
This PRL was published on 20 March, 2009, on behalf of the LSC (LIGO Scientific Collaboration). The Department of Physics, here at the University of Strathclyde, is a member of the LSC—through Dr Nicholas Lockerbie, and his co-worker Dr Kirill Tokmakov, who are both LSC co-authors of this letter: it reports the first results of the LIGO (Laser Interferometer Gravitational wave Observatory) science run S5 all-sky search, which was carried out during 2005–7.
LIGO’s two gravitational wave detector sites are based at Hanford, Washington State, in the NW, and Livingston, Louisiana, in the SE, of the USA, the two sites being separated by 3,000 km. At each site is a huge laser interferometer, measuring 4 km x 4 km, the Hanford site having an additional 2 km x 2 km interferometer, which shares the same, evacuated, beam tube. The interferometers are run in coincidence-detection mode, each monitoring changes in the ‘strain of spacetime,’ via differential movement of the test masses at the ends of its arms. LIGO is aimed primarily at the detection, via gravitational radiation, of catastrophic galactic events—such as the very brief inspiral and coalescence of binary neutron stars, black hole pairs, etc.
According to Einstein’s theory of General Relativity, all massive rotating bodies that possess, effectively, a non-zero mass-quadrupole moment, must emit gravitational waves. Indeed, the 1993 Nobel Prize for Physics was awarded to Joseph Taylor and Russell Hulse, for their discovery of the advancing periastron in the binary neutron-star system PSR B1913 +16, one of the neutron stars in this system being a radio pulsar. Here, the orbital decay of the binary system was found to follow closely Einstein’s prediction—if the system’s energy-loss were assumed to be due to gravitational radiation, alone. There were no adjustable parameters in the model used to fit the data.
Unfortunately, the very low frequencies of gravitational waves emitted by this, and by other known, binary neutron star systems (7.2 x 10-5 Hz, in the case of PSR B1913 +16), make them undetectable by LIGO, or by other ground-based gravitational-wave detectors, except during the last few seconds of their lives. A space-based detector called LISA (Laser Interferometer Space Antenna) is planned to enable the detection of such low frequency sources.
However, the study of pulsars, which may have relatively high rates of rotation—tens of Hz, or more—shows them to be potential gravity targets, provided they possess also a slightly eccentric shape. ‘Star quakes’ and subsequent small glitches in pulsar rotation rate have provided indirect evidence of such eccentricity, although the bulk of known pulsars lies in the 1–10 kpc, or greater, range of distance.
Within the (then) sensitivity of LIGO, and in the 50–1100 Hz range for detected gravity signals, no coherent (lightly-damped sinewave) gravitational wave sources were detected during the S5 run. This means that no pulsar sources with an equatorial ellipticity of 10-6 (considered to be the upper limit) was detected, out to a range of 500 pc. It is worth noting, however, that over a 200 Hz bandwidth the strain sensitivity of the LIGO detectors during this science run was nevertheless 10-24, this being equivalent to an interferometric displacement sensitivity of 2 x 10-21 m (!!)
LIGO is currently undergoing an upgrade in sensitivity (called ‘Advanced LIGO’), in which Strathclyde is actively involved. The upgrade should increase LIGO’s sensitivity by a factor of 10, and its detection rate of potential sources by factor of 1,000.
[NL]
Moving lasers from one lab to another without taking them apart? Yes we can...
Small stuff
New Grants
Dr Gordon Robb - Starter Grant - 14/04/09 - 13/04/10 - £10k
Professor Alan Phelps - "High power mm and sub-mm wave amplifiers for high frequency ESR/DNP, high resolution radar and remote sensing" - 01/04/09 - 30/09/12 - EPSRC - FEC: £946k, RC: £786k
Professor Alan Phelps - "Instabilities in non-thermal plasmas" - 01/04/09 - 31/03/13 - EPSRC - FEC: £1,280k, RC: £1,054k
Complex Networks
The Institute for Advanced Studies is holding a workshop on Applications of Complex Networks from 25 to 29 May. A description and programme can be found here (pdf, 138kB).
REF
An interesting brochure on the REF published by HEFCE can be found here. Another interesting story "Structural adjustments" was published in the Times Higher. The REF is coming and will be largely based on metrics so it it important to get ready. [KW, RM]
ResearcherID
Speaking of the REF: one way to get more exposure is by using ResearcherId. You can get to it via WOS (once you are logged in, menu, bottom right hand side) and create a list of all your papers. It will generate a web page for you with your papers, citations, WOS links, h-index, keywords, etc. A button is available to be put on your website. If you want such a button placed on your staff page, pass the code snippet on to Ricky or myself. As an example, look at the page for Miles Padgett. [KW]
DOIs
If you use FireFox, a handle extension enables the browser to access handle URIs such as DOIs. It works well for when the SFX linking from WOS doesn't link properly (which seems to happen more and more frequenctly). In fact, it's much faster than using SFX linking. Just double click the DOI in a WOS record, remove the space, and off you go to the paper. [KW]
Special collection: the NJP Best of 2008
Ken Ledingham's paper "Study of photo-proton reactions driven by bremsstrahlung radiation of high intensity laser generated electrons" in the New Journal of Physics was chosen NJP Best of 2008. The entire NJP Best of 2008 collection is accessible free of charge. [KW]
Blogs
Do you blog? More and more scientists have blogs. Science blogs collects a number of blogs together. The website Ars Technica has a science section that is for all intends and purposes a blog. One of my recent favoureds is Female Science professor. Not a blog but still interesting (or beautiful anyway) is SEED magazine. I wrote a few things for the Survival blog for scientists. Let me know of you blog too. [KW]
Quantum information published
After more years than he would care to count, Steve Barnett's new book Quantum Information is about to appear. It is a textbook aimed at final year undergraduate students and beginning postgraduate students, which has evolved from the SUPA postgraduate course. It provides an introduction to all the key elements of the subject, including such hot topics as quantum cryptograpy and quantum computers. Published by Oxford University Press, the first copies will appear in May. Order your copy now to avoid disappointment!
[SB]
Prize student causes stir
Jennifer Noble, a 2nd year SUPA Prize PhD Student and University Scholar, who is currently studying for her PhD with Dr Helen Fraser in the Department of Physics, spent the last four months of 2008 in Japan, at the University of Kobe, where she held a JSPS Fellowship. Whilst there, she worked extensively with Prof Y Aikawa and Dr I Sakon to develop techniques to extract spectra from observations made with the Japanese satellite AKARI towards a number of star-forming regions. Such regions are very cold and dark, yet produce a plethora of molecules, most of which are frozen out as 'ices' in star-forming regions. Her work, focusing on one core in particular, called B35a, near to the 'top' of Orion, was featured in the AKARI scientific conference in Tokyo in February, and is now causing quite a stir - Jenny will present her work at two international meetings this summer - the IAU in Brazil (an Astronomy meeting) - for which she has been awarded an IAU Travel award, and the 42nd IUPAC (a Chemistry meeting) in Glasgow.
Jenny's initial AKARI results hint that CO2 ices can form where no other ices (like H2O or CO) seem to be present - a completely unexpected result from our current understanding of star-formation chemistry. So, not content with these awards behind her, Jenny has recently been awarded a Leverhulme Fellowship and SIET Travel Award to fund 12 months research on secondment in Universite de Cergy-Pontoise / l'Observatoire de Paris, where she will be working in the laboratory to study the chemical pathways to CO2 ice formation under pseudo-interstellar conditions. She will spend the 2009/10 academic session in France, returning to complete her PhD in Strathclyde afterwards.
[HF]
SUPA Research Highlighted in Physical Review Letters
Research by Dr Daniel Oi (SUPA Advanced Research Fellow), in conjunction with experimentalists at the Cavendish Laboratory (University of Cambridge), was recently highlighted as an Editors' Suggestion in Physical Review Letters [Phys. Rev. Lett. 102, 156801 (2009)]. To promote reading across fields, the editors of Physical Review Letters offer "Suggestions" each week of papers that they hope will lead readers to explore other areas of physics.
The research examined the picosecond dynamics of a single electron trapped in a moving quantum dot generated by a surface acoustic wave (SAW). A static electrode array creates an effective time-dependent potential for the moving quantum dot; due to the velocity of the SAW (~2800m/s) and the dimensions of the electrodes (~nm) the variation can be much faster than can be generated using electrical signals applied to a stationary dot.
Past gate-pulse experiments have successfully measured the charge states of double quantum dots containing many electrons, but never in the single electron regime where the faster dynamics have exceeded experimental bandwidth. In this experiment, coherent oscillations of the electron wavefunction was observed as it traversed a tunnelling barrier, the sudden change in the electrostatic potential seen by the moving quantum dot creates a superposition of energy eigenstates whose beat frequencies (~200GHz) lead to variations in the tunnelling current.
The successful demonstration of this technique opens up new possibilities to investigate ultra-fast electron dynamics in the solid-state without the need for ultra-fast pulses and detectors. This may lead to quantum devices based on single-electron SAW quantum dots.
[DO]
Emergency repair
John Broadfoot, and Gerard (Ged) Drinkwater, who are technical staff from the Department’s Electronics Workshop, travelled out to Pasadena, USA, recently (18–25 April), and spent a week working out in CalTech. Their task there was to repair a piece of research equipment which had been designed, built, and tested, at Strathclyde, and which subsequently had been air-freighted out to CalTech, for use potentially in the Advanced LIGO upgrade to the USA’s LIGO Gravitational Wave detectors. Unfortunately, on first switch-on the equipment was found to have been damaged, and its repair required specialised knowledge. The equipment is in fact a water-cooled ultra-low-noise 6-channel ‘Electrostatic Driver’, each channel of which is capable of producing outputs of up to 800 volts peak-peak, from DC up to 20 kHz—with an input-referred noise level of below 25 nV rms, per ÖHz (!). Its intended application is the cold-damping of seismically-induced vibrations in LIGO’s silica suspension fibres, which support the interferometers’ mirrors. The repair was entirely successful, and the instrument is now working at its design specification. The repair is being funded under an STFC grant (UK involvement in the Advanced LIGO Gravitational Wave Project) held by the University of Birmingham, Dr N.A. Lockerbie of this department being a Co-I under this £1.4M grant.
[NL]
In May 2009, the BCP group was allowed to move into a new lab on the 3rd floor of JA, funded by an S&I grant in nanometrology, the University, and the faculty of Science. It contains three laser labs (shown above), a prep area, a chemistry lab, a physics & life-sciences lab, and an entertainment / conference area.
[KW]
