All Outputs (2150)

The gravitational dynamics of warped throats (2010)
Journal Article
Butcher, N. A., & Saffin, P. M. (in press). The gravitational dynamics of warped throats. Journal of High Energy Physics, 2010(6), https://doi.org/10.1007/JHEP06%282010%29044

We investigate the time evolution due to gravitational dynamics of a particular spacetime commonly used in brane-cosmology and string compactifications, namely the Klebanov-Strassler geometry, which is achieved by adding a perturbation to the momentu... Read More about The gravitational dynamics of warped throats.

A pictorial visualization of normal mode vibrations of the fullerene C_60 molecule in terms of vibrations of a hollow sphere (2010)
Journal Article
Dunn, J. L. (2010). A pictorial visualization of normal mode vibrations of the fullerene C_60 molecule in terms of vibrations of a hollow sphere. Journal of Chemical Education, https://doi.org/10.1021/ed100263f

Understanding the normal mode vibrations of a molecule is important in the analysis of vibrational spectra. However, the complicated 3D motion of large molecules can be difficult to interpret. We show how images of normal modes of the fullerene molec... Read More about A pictorial visualization of normal mode vibrations of the fullerene C_60 molecule in terms of vibrations of a hollow sphere.

The change in cerebrovascular reactivity between 3T and 7T measured using graded hypercapnia (2010)
Journal Article
Driver, I., Blockley, N., Fisher, J., Francis, S., & Gowland, P. A. (2010). The change in cerebrovascular reactivity between 3T and 7T measured using graded hypercapnia. NeuroImage, 51(1), https://doi.org/10.1016/j.neuroimage.2009.12.113

Mapping cerebrovascular reactivity (CVR) to hypercapnia is important both clinically and for improved understanding of the haemodynamic properties of the BOLD effect. In this work BOLD/R2* CVR was investigated by using a device which provided small,... Read More about The change in cerebrovascular reactivity between 3T and 7T measured using graded hypercapnia.

The effect of cooperative Jahn–Teller interactions on C60− anions (2010)
Journal Article
Moujaes, E. A., & Dunn, J. L. (2010). The effect of cooperative Jahn–Teller interactions on C60− anions. Journal of Physics: Condensed Matter, 22(8), https://doi.org/10.1088/0953-8984/22/8/085007

Singly charged buckminsterfullerene anions, C60−, are subject to a strong intramolecular T [circle times] h Jahn–Teller (JT) effect. When such ions interact with other C60− ions in a solid through a cooperative JT effect, they will be subject to an... Read More about The effect of cooperative Jahn–Teller interactions on C60− anions.

Calculation of images of oriented C_60 molecules using molecular orbital theory (2010)
Journal Article
Hands, I. D., Dunn, J. L., & Bates, C. A. (2010). Calculation of images of oriented C_60 molecules using molecular orbital theory. Physical Review B, 81(20), https://doi.org/10.1103/PhysRevB.81.205440

Using Hückel molecular-orbital theory, images are created to represent the electron distributions expected for a C60 molecule adsorbed on a substrate. Three different orientations of the C60 molecule on the substrate are considered. The effect of t... Read More about Calculation of images of oriented C_60 molecules using molecular orbital theory.

Jahn-Teller effects in molecules on surfaces with specific application to C_60 (2010)
Book Chapter
Hands, I. D., Dunn, J. L., Rawlinson, C. S., & Bates, C. A. (2010). Jahn-Teller effects in molecules on surfaces with specific application to C_60. In H. Köppel, D. R. Yarkony, & H. Barentzen (Eds.), The Jahn-Teller effect: fundamentals and implications for physics and chemistry. Springer-Verlag

Scanning tunnelling microscopy (STM) is capable of imaging molecules adsorbed onto surfaces with su±cient resolution as to permit intramolecular features to be discerned. Therefore, imaging molecules subject to the Jahn-Teller (JT) effect could, in... Read More about Jahn-Teller effects in molecules on surfaces with specific application to C_60.

Evolution and stability of cosmic string loops with Y-junctions (2009)
Journal Article
Bevis, N., Copeland, E. J., Martin, P.-Y., Niz, G., Pourtsidou, A., Saffin, P. M., & Steer, D. (2009). Evolution and stability of cosmic string loops with Y-junctions. Physical Review D, 80(12), https://doi.org/10.1103/PhysRevD.80.125030

We study the evolution of non-periodic cosmic string loops containing Y-junctions, such as may form during the evolution of a network of (p,q) cosmic superstrings. We set up and solve the Nambu-Goto equations of motion for a loop with junctions, focu... Read More about Evolution and stability of cosmic string loops with Y-junctions.

Cosmological and astrophysical constraints from the Lyman α forest flux probability distribution function (2009)
Journal Article
Viel, M., Bolton, J. S., & Haehnelt, M. G. (2009). Cosmological and astrophysical constraints from the Lyman α forest flux probability distribution function. Monthly Notices of the Royal Astronomical Society: Letters, 399(1), L39–L43. https://doi.org/10.1111/j.1745-3933.2009.00720.x

Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations (2009)
Journal Article
S. Bolton, J., & D. Becker, G. (2009). Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations. Monthly Notices of the Royal Astronomical Society: Letters, 398(1), L26–L30. https://doi.org/10.1111/j.1745-3933.2009.00700.x

We use a large set of cosmological smoothed particle hydrodynamics (SPH) simulations to examine the effect of mass resolution and box size on synthetic Lya forest spectra at 2 \leq z \leq 5. The mass resolution requirements for the convergence of the... Read More about Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations.

Strong coupling in Hořava gravity (2009)
Journal Article
Charmousis, C., Niz, G., Padilla, A., & Saffin, P. M. (2009). Strong coupling in Hořava gravity. Journal of High Energy Physics, 2009(8), https://doi.org/10.1088/1126-6708/2009/08/070

By studying perturbations about the vacuum, we show that Horava gravity suffers from two different strong coupling problems, extending all the way into the deep infra-red. The first of these is associated with the principle of detailed balance and ex... Read More about Strong coupling in Hořava gravity.

Cosmological constraints on f(G) dark energy models (2009)
Journal Article
Zhou, S.-Y., Copeland, E. J., & Saffin, P. M. (2009). Cosmological constraints on f(G) dark energy models. Journal of Cosmology and Astroparticle Physics, 2009(7), https://doi.org/10.1088/1475-7516/2009/07/009

Modified gravity theories with the Gauss-Bonnet term G=R2−4RμνRμν+RμνρσRμνρσ have recently gained a lot of attention as a possible explanation of dark energy. We perform a thorough phase space analysis on the so-called f(G) models, where f(G) is some... Read More about Cosmological constraints on f(G) dark energy models.

The evolution of the Lyman-alpha forest effective optical depth following HeII reionisation (2009)
Journal Article
S. Bolton, J., Peng Oh, S., & R. Furlanetto, S. (2009). The evolution of the Lyman-alpha forest effective optical depth following HeII reionisation. Monthly Notices of the Royal Astronomical Society, 396(4), 2405–2418. https://doi.org/10.1111/j.1365-2966.2009.14914.x

Three independent observational studies have now detected a narrow (\Delta z ~ 0.5) dip centred at z=3.2 in the otherwise smooth redshift evolution of the Lya forest effective optical depth. This feature has previously been interpreted as an indirect... Read More about The evolution of the Lyman-alpha forest effective optical depth following HeII reionisation.

Photo-heating and the fate of hard photons during the reionisation of HeII by quasars (2009)
Journal Article
S. Bolton, J., Peng Oh, S., & R. Furlanetto, S. (2009). Photo-heating and the fate of hard photons during the reionisation of HeII by quasars. Monthly Notices of the Royal Astronomical Society, 395(2), 736–752. https://doi.org/10.1111/j.1365-2966.2009.14597.x

We use a combination of analytic and numerical arguments to consider the impact of quasar photo-heating during HeII reionisation on the thermal evolution of the intergalactic medium (IGM). We demonstrate that rapid (\Delta z< 0.1-0.2), strong (\Delta... Read More about Photo-heating and the fate of hard photons during the reionisation of HeII by quasars.

Galaxy Zoo: Chiral correlation function of galaxy spins (2009)
Journal Article
Slosar, A., Land, K., Bamford, S., Lintott, C., Andreescu, D., Murray, P., …Vandenberg, J. (2009). Galaxy Zoo: Chiral correlation function of galaxy spins. Monthly Notices of the Royal Astronomical Society, 392(3), 1225–1232. https://doi.org/10.1111/j.1365-2966.2008.14127.x

Galaxy Zoo is the first study of nearby galaxies that contains reliable information about the spiral sense of rotation of galaxy arms for a sizeable number of galaxies. We measure the correlation function of spin chirality (the sense in which galaxie... Read More about Galaxy Zoo: Chiral correlation function of galaxy spins.

Interaction of MRI field gradients with the human body (2009)
Journal Article
Glover, P. (2009). Interaction of MRI field gradients with the human body. Physics in Medicine and Biology, 54(21), Article R99-R115. https://doi.org/10.1088/0031-9155/54/21/R01

In this review, the effects of low-frequency electromagnetic fields encountered specifically during magnetic resonance imaging (MRI) are examined. The primary biological effect at frequencies of between 100 and 5000 Hz (typical of MRI magnetic field... Read More about Interaction of MRI field gradients with the human body.

The evolution of conifolds (2008)
Journal Article
Butcher, N. A., & Saffin, P. M. (2008). The evolution of conifolds. Journal of High Energy Physics, 2008(12), https://doi.org/10.1088/1126-6708/2008/12/012

We simulate the gravitational dynamics of the conifold geometries (resolved and deformed) involved in the description of certain compact spacetimes. As the cycles of the conifold collapse towards a singular geometry we find that a horizon develops, s... Read More about The evolution of conifolds.

Some stationary properties of a Q-ball in arbitrary space dimensions (2008)
Journal Article
Tsumagari, M. I., Copeland, E. J., & Saffin, P. M. (2008). Some stationary properties of a Q-ball in arbitrary space dimensions. Physical Review D, 78(6), https://doi.org/10.1103/PhysRevD.78.065021

Introducing new physically motivated ansaetze, we explore both analytically and numerically the classical and absolute stabilities of a single Q-ball in an arbitrary number of spatial dimensions D, working in both the thin and thick wall limits.

Transmission of an inhomogeneous state via resonant tunnelling (2008)
Journal Article
Saffin, P. M., Padilla, A., & Copeland, E. J. (2008). Transmission of an inhomogeneous state via resonant tunnelling. Journal of High Energy Physics, 2008(9), https://doi.org/10.1088/1126-6708/2008/09/055

We recently investigated the nature of resonant tunnelling in standard scalar Quantum Field Theory, uncovering the conditions required for resonance. It was shown that whereas the homogeneous false vacuum may decay via bubble nucleation, it may not d... Read More about Transmission of an inhomogeneous state via resonant tunnelling.

Cosmic string Y-junctions: a comparison between field theoretic and Nambu-Goto dynamics (2008)
Journal Article
Bevis, N., & Saffin, P. M. (2008). Cosmic string Y-junctions: a comparison between field theoretic and Nambu-Goto dynamics. Physical Review D, 78(2), https://doi.org/10.1103/PhysRevD.78.023503

We explore the formation of cosmic string Y-junctions when strings of two different types collide, which has recently become important since string theory can yield cosmic strings of distinct types. Using a model containing two types of local U(1) st... Read More about Cosmic string Y-junctions: a comparison between field theoretic and Nambu-Goto dynamics.

Fingering Instabilities in Dewetting Nanofluids (2008)
Journal Article
Pauliac-Vaujour, E., Stannard, A., Martin, C., Blunt, M., Notingher, I., Moriarty, P., …Thiele, U. (2008). Fingering Instabilities in Dewetting Nanofluids. Physical Review Letters, 100,

The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises fro... Read More about Fingering Instabilities in Dewetting Nanofluids.