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Current Search:
'Physics' in all fields;
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Displaying Results 1 - 25 of 1489 on page 1 of 60
Marked
Mark
A phenomenographic study of introductory physics students: approaches to problem solving and conceptualisation of knowledge.
(2009)
Walsh, Laura, (Thesis)
A phenomenographic study of introductory physics students: approaches to problem solving and conceptualisation of knowledge.
(2009)
Walsh, Laura, (Thesis)
Abstract:
<p>This phenomenographic study presents a description of the approaches to problem solving and conceptualisation of physics knowledge of introductory physics students, specifically in the context of the Irish higher education system. Much research has been carried out that has shown that physics students are not developing the conceptual knowledge necessary to become adept problem-solvers. This may be due to the traditional physics education assumption that students will develop an understanding of the conceptual nature of physics by repetitively solving quantitative problems. However, research has shown that this is not the case and that education and the curriculum needs to explicitly reflect the qualitative and quantitative nature of physics. This empirical study was conducted using phenomenographic assumptions and methodology to collect, analyse and interpret data from forty two individual semistructured interviews with introductory physics students. This study presents a ...
http://arrow.dit.ie/sciendoc/61
Marked
Mark
An investigation of Introductory Physics Students’ Approaches to Problem Solving
(2007)
Walsh, Laura; Howard, Robert; Bowe, Brian
An investigation of Introductory Physics Students’ Approaches to Problem Solving
(2007)
Walsh, Laura; Howard, Robert; Bowe, Brian
Abstract:
<p>This paper outlines ongoing research investigating students’ approaches to quantitative and qualitative problem solving in physics. This is an empirical study, which was conducted using a phenomenographic approach to analyse and interpret data from individual semi-structured interviews with students from introductory physics courses. The result of the study thus far is a preliminary set of hierarchical categories that describe the students’ problem-solving approaches when faced with various physics problems. The findings from the research presented here indicate that many introductory students in higher education do not approach problem solving in a strategic manner and many do not try to link or use their physics knowledge in order to solve problems.</p>
http://arrow.dit.ie/scschphyart/1
Marked
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A Phenomenographic Study of Introductory Physics Students: Approaches to their Learning and Perceptions of their Learning Environment in a Physics Problem-Based Learning Environment
(2010)
Irving, Paul, (Thesis)
A Phenomenographic Study of Introductory Physics Students: Approaches to their Learning and Perceptions of their Learning Environment in a Physics Problem-Based Learning Environment
(2010)
Irving, Paul, (Thesis)
Abstract:
<p>This phenomenographic study describes students’ approaches to learning and their perceptions of the learning environment in an introductory physics course which is taught using a problem-based learning approach. This research builds on previous studies which showed that these students develop a greater conceptual knowledge than their counterparts in a more traditional learning environment while others showed very little development even though they engaged fully with the pedagogy. This study aimed to examine and describe the students’ approaches to learning. The definitions of surface, strategic and deep approaches to learning are not appropriate in this context and could not be applied as all students engage fully in the collaborative problem-solving process, albeit in different ways, and hence displayed none of the characteristics of the traditional surface approach and many, if not all, of those associated with the deep approach. Many previous research studies have shown...
http://arrow.dit.ie/sciendoc/96
Marked
Mark
Magnetic moment investigations of epitaxial magnetite thin films
(2008)
ARORA, SUNIL KUMAR; SHVETS, IGOR
Magnetic moment investigations of epitaxial magnetite thin films
(2008)
ARORA, SUNIL KUMAR; SHVETS, IGOR
Abstract:
In this report, we provide an x-ray magnetic circular dichroism (XMCD) study for 100 nm thick epitaxial magnetite (Fe3O4) films on MgO (001) and Al2O3 (0001) substrates. For XMCD, we recorded the surface sensitive total electron yield and the bulk sensitive transmission spectra. From the analysis of the XMCD data, we find an increased Fe spin moment (10% larger) at the surface of the film on MgO (100) with respect to the corresponding bulk value of the film. Surface and bulk spin moments of the film on Al2O3(0001) are almost equal. For both films, the bulk orbital to spin moments ratio increases from zero at 70 K to 0.03–0.04 at 300 K. For Fe3O4/MgO (001), the surface orbital to spin moment ratio behaves similarly to the bulk value, while the orbital to spin moments ratio is increased at the Fe3O4/Al2O3 (0001) surface to 0.06. The observed differences between films grown on MgO and Al2O3 are explained within the framework of differences in mismatch strain experienced by the films.
http://hdl.handle.net/2262/40321
Marked
Mark
Misorientations in [001] magnetite thin films studied by electron backscatter diffraction and magnetic force microscopy
(2007)
SHVETS, IGOR; MURPHY, SHANE
Misorientations in [001] magnetite thin films studied by electron backscatter diffraction and magnetic force microscopy
(2007)
SHVETS, IGOR; MURPHY, SHANE
Abstract:
Magnetite thin films grown on 001 oriented MgO substrates are analyzed by means of electron backscatter diffraction EBSD analysis and magnetic force microscopy in applied fields. The EBSD technique enables the crystallographic orientation of individual grains to be determined with a high spatial resolution up to 20 nm on such ceramic samples. A high image quality of the recorded Kikuchi patterns was achieved enabling multiphase scans and high spatial resolution measurements. Upon annealing in air, the magnetic properties of the magnetite thin films were found to change considerably. Using the EBSD analysis, we find that misoriented grains remaining after the annealing step form small islands with a size of about 100 nm. The size and distribution of these islands correspond well to the observations of antiferromagnetic pinning centers within the magnetic domain structures carried out by magnetic force microscopy on the same samples.
http://hdl.handle.net/2262/40431
Marked
Mark
The new physics of non-equilibrium condensates: insights from classical dynamics
(2007)
EASTHAM, PAUL
The new physics of non-equilibrium condensates: insights from classical dynamics
(2007)
EASTHAM, PAUL
Abstract:
We discuss the dynamics of classical Dicke-type models, aiming to clarify the mechanisms by which coherent states could develop in potentially non-equilibrium systems such as semiconductor microcavities. We present simulations of an undamped model which show spontaneous coherent states with persistent oscillations in the magnitude of the order parameter. These states are generalisations of superradiant ringing to the case of inhomogeneous broadening. They correspond to the persistent gap oscillations proposed in fermionic atomic condensates, and arise from a variety of initial conditions. We show that introducing randomness into the couplings can suppress the oscillations, leading to a limiting dynamics with a time-independent order parameter. This demonstrates that non-equilibrium generalisations of polariton condensates can be created even without dissipation. We explain the dynamical origins of the coherence in terms of instabilities of the normal state, and consider how it can a...
http://hdl.handle.net/2262/49379
Marked
Mark
Central Charge and Quasihole Scaling Dimensions From Model Wavefunctions: Towards Relating Jack Wavefunctions to W-algebras
(2009)
Bernevig, B. Andrei; Gurarie, Victor; Simon, Steven H.
Central Charge and Quasihole Scaling Dimensions From Model Wavefunctions: Towards Relating Jack Wavefunctions to W-algebras
(2009)
Bernevig, B. Andrei; Gurarie, Victor; Simon, Steven H.
Abstract:
We present a general method to obtain the central charge and quasihole scaling dimension directly from groundstate and quasihole wavefunctions. Our method applies to wavefunctions satisfying specific clustering properties. We then use our method to examine the relation between Jack symmetric functions and certain W-algebras. We add substantially to the evidence that the (k, r) admissible Jack functions correspond to correlators of the conformal field theory Wk(k+1, k+r), by calculating the central charge and scaling dimensions of some of the fields in both cases and showing that they match. For the Jacks described by unitary W-models, the central charge and quasihole exponents match the ones previously obtained from analyzing the physics of the edge excitations. For the Jacks described by non-unitary W-models the central charge and quasihole scaling dimensions obtained from the wavefunctions differ from the ones obtained from the edge physics, which instead agree with the “effective...
http://eprints.nuim.ie/2693/
Marked
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Implementing an inquiry based approach in first year undergraduate physics laboratories with emphasis on improving graphing literacy
(2010)
Wemyss, Thomas
Implementing an inquiry based approach in first year undergraduate physics laboratories with emphasis on improving graphing literacy
(2010)
Wemyss, Thomas
Abstract:
We have developed the first year undergraduate physics labs to incorporate both open and guided inquiry in a flexible approach. By doing this we have shown that there have been benefits in both the affective and the cognitive domain for our students. One of the main aims for the labs was to develop necessary transferable scientific skills. Developing graphing skills was an important part of the work that we did in the labs. Through our work we have developed assessments to test students’ general graphing literacy and developed curriculum to tackle their difficulties. The difficulties addressed are with both qualitative and quantitative graphs.
http://doras.dcu.ie/15130/
Marked
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On the Road Again: Metal Foams Find Favor
(2002)
WEAIRE, DENIS LAWRENCE
On the Road Again: Metal Foams Find Favor
(2002)
WEAIRE, DENIS LAWRENCE
Abstract:
The three states of matter are well represented by earth, sea, and sky. God saw that it was good, and so did many generations of physics lecturers. But purity is obscurity, as Ogden Nash reminded us. The rich variety of combinations of gas, liquid, and solid that are found in nature's creations and mankind's artifacts presents us with an infinity, rather than a trinity, of possibilities.
http://hdl.handle.net/2262/41098
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Forked:A Demonstration of Physics Realism in Augmented Reality
(2009)
Beaney, David; Mac Namee, Brian
Forked:A Demonstration of Physics Realism in Augmented Reality
(2009)
Beaney, David; Mac Namee, Brian
Abstract:
In making fully immersive augmented reality (AR) applications, real and virtual objects will have to be seen to physically interact together in a realistic and believable way. This paper describes Forked! a system that has been developed to show how physical interactions between real and virtual objects can be simulated re- alistically and believably through appropriate use of a physics en- gine. The system allows users control a robotic forklift to manipu- late virtual crates in an AR environment. The paper also describes a evaluation experiment in which it is shown that the physical inter- actions between the forklift and the virtual creates are realistic and believable enough to be comparable with the physical interactions between a forklift and real crates.
http://arrow.dit.ie/scschcomcon/55
Marked
Mark
Towards a Field-Programmable Physics Processor (FP³)
(2006)
WOULFE, MUIRIS; MANZKE, MICHAEL
Towards a Field-Programmable Physics Processor (FP³)
(2006)
WOULFE, MUIRIS; MANZKE, MICHAEL
Abstract:
In this paper, we outline the design and implementation of an FPGA-based numerical integrator that will ultimately form the basis of our FPGA-based physics engine. Physics engines are considered one of the most important of a multitude of components requesting CPU time in a modern computer game, and so we propose offloading aspects of this physics computation to an FPGA-based physics engine. We aim to ameliorate the speed of the physics computation in concert with the other game components. Currently, our physics processor uses the fourth-order Runge-Kutta numerical integration algorithm to solve the ordinary differential equations used in game physics. Our analyses indicate that the performance of our physics processor should surpass that of the equivalent software executing on a CPU when several objects are simulated.
http://hdl.handle.net/2262/36008
Marked
Mark
Collisionless heating in radio-frequency discharges: a review
(2009)
Turner, Miles M.
Collisionless heating in radio-frequency discharges: a review
(2009)
Turner, Miles M.
Abstract:
Radio-frequency discharges are practically and scientifically interesting. A practical understanding of such discharges requires, among other things, a quantitative appreciation of the mechanisms involved in heating electrons, since this heating is the proximate cause of the ionization that sustains the plasma. When these discharges are operated at sufficiently low pressure, collisionless electron heating can be an important and even the dominant mechanism. Since the low pressure regime is important for many applications, understanding collisionless heating is both theoretically and practically important. This review is concerned with the state of theoretical knowledge of collisionless heating in both inductive and capacitive discharges.
http://doras.dcu.ie/14889/
Marked
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Uniaxial stress studies of the Be pair bound exciton absorption spectrum in silicon
(1984)
Mulligan, F.J.; Henry, M.O.; Moloney, K.A.; Treacy, J.; Lightowlers, E.C.
Uniaxial stress studies of the Be pair bound exciton absorption spectrum in silicon
(1984)
Mulligan, F.J.; Henry, M.O.; Moloney, K.A.; Treacy, J.; Lightowlers, E.C.
Abstract:
The authors report the results of preliminary uniaxial stress studies of the beryllium pair isoelectronic bound exciton absorption spectrum in silicon. The results confirm that the exciton behaves as an isoelectronic acceptor.
http://eprints.nuim.ie/814/
Marked
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Electron and ion stagnation at the collision front between two laser produced plasmas
(2009)
Hough, Pádraig; McLoughlin, Conor; Kelly, Thomas J.; Hayden, Patrick; Harilal, Sivanand...
Electron and ion stagnation at the collision front between two laser produced plasmas
(2009)
Hough, Pádraig; McLoughlin, Conor; Kelly, Thomas J.; Hayden, Patrick; Harilal, Sivanandan S.; Mosnier, Jean-Paul; Costello, John T.
Abstract:
We report results from a combined optical interferometric and spectrally resolved imaging study on colliding laser produced aluminium plasmas. A Nomarski interferometer was used to probe the spatio-temporal distribution of electron densities at the collision front. Analysis of the resulting interferograms reveals the formation and evolution of a localized electron density feature with a well-defined profile reminiscent of a stagnation layer. Electron stagnation begins at a time delay of 10 ns after the peak of the plasma generating laser pulse. The peak electron density was found to exceed 10^19 cm^−3 and the layer remained well defined up to a time delay of ca 100 ns. Temporally and spectrally resolved optical imaging was also undertaken, to compare the Al^+ ion distribution with that of the 2D electron density profile. This revealed nascent stagnation of singly charged ions at a delay time of 20 ns. We attribute these results to the effects of space charge separation in the seed p...
http://doras.dcu.ie/15134/
Marked
Mark
Non-locality of non-Abelian anyons
(2009)
Brennen, G.K.; Iblisdir, S.; Pachos, J.K.; Slingerland, J.K.
Non-locality of non-Abelian anyons
(2009)
Brennen, G.K.; Iblisdir, S.; Pachos, J.K.; Slingerland, J.K.
Abstract:
Entangled states of quantum systems can give rise to measurement correlations of separated observers that cannot be described by local hidden variable theories. Usually, it is assumed that entanglement between particles is generated due to some distance-dependent interaction. Yet anyonic particles in two dimensions have a nontrivial interaction that is purely topological in nature. In other words, it does not depend on the distance between two particles, but rather on their exchange history. The information encoded in anyons is inherently non-local even in the single subsystem level making the treatment of anyons nonconventional. We describe a protocol to reveal the non-locality of anyons in terms of correlations in the outcomes of measurements in two separated regions. This gives a clear operational measure of non-locality for anyonic states and it opens up the possibility to test Bell inequalities in quantum Hall liquids or spin lattices.
http://eprints.nuim.ie/1878/
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The magnetic and magnetoresistance properties of ultrathin magnetite films grown on MgO substrate
(2006)
SHVETS, IGOR; MC EVOY, CIARAN; RAMOS, RAFAEL
The magnetic and magnetoresistance properties of ultrathin magnetite films grown on MgO substrate
(2006)
SHVETS, IGOR; MC EVOY, CIARAN; RAMOS, RAFAEL
Abstract:
We report on the properties of ultrathin (2, 4, 6, and 8 nm) epitaxial films of magnetite, Fe3O4, grown on MgO (100). Atomic force microscopy image and V-I curves suggest that the films at this thickness are still continuous. The resistivity versus temperature results imply that the conductivity mechanism in all these films is similar. The resistivity of 4 nm thick film is much greater than that of 6 and 8 nm films. The films show ferrimagnetic instead of reported superparamagnetic behavior. The dead layer formed by Mg diffusion between MgO substrate and magnetite films and also the dead layer on the top uncapped film could be the possible reasons for the anomalous resistivity and magnetic properties of the ultrathin films. The effect of the “dead layer” in the thinner film is relatively greater than the one in the thicker film and should lead to a lower magnetoresistance.
http://hdl.handle.net/2262/40423
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A dipole polarizable potential for reduced and doped CeO(2) obtained from first principles.
(2011)
WATSON, GRAEME WILLIAM
A dipole polarizable potential for reduced and doped CeO(2) obtained from first principles.
(2011)
WATSON, GRAEME WILLIAM
Abstract:
In this paper we present the parameterization of a new interionic potential for stoichiometric, reduced and doped CeO2. We use a dipole polarizable potential (DIPPIM: the dipole polarizable ion model) and optimize its parameters by fitting them to a series of density functional theory calculations. The resulting potential was tested by calculating a series of fundamental properties for CeO2 and by comparing them against experimental values. The values for all the calculated properties (thermal and chemical expansion coefficients, lattice parameters, oxygen migration energies, local crystalline structure and elastic constants) are within 10–15% of the experimental ones, an accuracy comparable to that of ab initio calculations. This result suggests the use of this new potential for reliably predicting atomic scale properties of CeO2 in problems where ab initio calculations are not feasible due to their size limitations.
http://hdl.handle.net/2262/56909
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Spectral distribution of atomic fluorescence coupled into an optical nanofibre
(2009)
Russell, Laura; Gleeson, Daniel A.; Minogin, V. G. (Vladimir Georgievich), 1950-; Nic C...
Spectral distribution of atomic fluorescence coupled into an optical nanofibre
(2009)
Russell, Laura; Gleeson, Daniel A.; Minogin, V. G. (Vladimir Georgievich), 1950-; Nic Chormaic, Síle
Abstract:
Science Foundation Ireland (06/W.1/I866); Science Foundation Ireland (07/RFP/PHYF518; Irish Research Council for Science Engineering and Technology (Embark Initiative); Russian Foundation for Basic Research (07-02-00748)
Accepted Version
We analyse the lineshape of the fluorescence emitted by a cloud of optically excited cold atoms and coupled into an optical nanofibre. We examine the efficiency of the fluorescence coupling and describe the asymmetry of the lineshape caused by the redshifts arising from both the van der Waals and Casimir-Polder interaction of the atoms with the surface of the optical nanofibre. We compare the contributions of the van der Waals and Casimir-Polder redshifts and show that the lineshape of the fluorescence coupled into an optical nanofibre is, basically, influenced by the van der Waals redshift and is characterized by a long tail on the red side of the spectrum. We conclude that a measurement of the lineshape of the coupled fluorescence could be...
http://hdl.handle.net/10468/361
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Effects of excitonic diffusion on stimulated emission in nanocrystalline ZnO
(2006)
Tobin, Ger; McGlynn, Enda; Henry, Martin O.; Mosnier, Jean-Paul; de Posada, Eduardo; Lu...
Effects of excitonic diffusion on stimulated emission in nanocrystalline ZnO
(2006)
Tobin, Ger; McGlynn, Enda; Henry, Martin O.; Mosnier, Jean-Paul; de Posada, Eduardo; Lunney, James G.
Abstract:
We present optically-pumped emission data for ZnO, showing that high excitation effects and stimulated emission / lasing are observed in nanocrystalline ZnO thin films at room temperature, although such effects are not seen in bulk material of better optical quality. A simple model of exciton density profiles is developed which explains our results and those of other authors. Inhibition of exciton diffusion in nanocrystalline samples compared to bulk significantly increases exciton densities in the former, leading, via the nonlinear dependence of emission in the exciton bands on the pump intensity, to large increases in emission and to stimulated emission.
http://doras.dcu.ie/2/
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Single-shot characterization of independent femtosecond extreme ultraviolet free electron and infrared laser pulses
(2007)
Dardis, John; Kavanagh, Kevin D.; Pedregosa-Gutierrez, Jofre; Yeates, Pat; Kennedy, Eug...
Single-shot characterization of independent femtosecond extreme ultraviolet free electron and infrared laser pulses
(2007)
Dardis, John; Kavanagh, Kevin D.; Pedregosa-Gutierrez, Jofre; Yeates, Pat; Kennedy, Eugene T.; Costello, John T.
Abstract:
Two-color above threshold ionization of helium and xenon has been used to analyze the synchronization between individual pulses of the femtosecond extreme ultraviolet (XUV) Free electron LASer in Hamburg and an independent intense 120 fs mode-locked Ti:Sa laser. Characteristic sidebands appear in the photoelectron spectra when the two pulses overlap spatially and temporally. The cross-correlation curve points to a 250 fs r.m.s. jitter between the two sources at the experiment. A more precise determination of the temporal fluctuation between the XUV and infrared pulses is obtained through the analysis of the single-shot sideband intensities.
http://doras.dcu.ie/74/
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Photoionization experiments with the ultrafast EUV laser 'FLASH' - free electron laser in Hamburg
(2007)
Costello, John T.
Photoionization experiments with the ultrafast EUV laser 'FLASH' - free electron laser in Hamburg
(2007)
Costello, John T.
Abstract:
The advent of mirror-less Free Electron Lasers emitting polarised and coherent 'laser-like' beams of high peak (> 1GW) and average (up to 100mW) powers in the extreme-UV (EUV) and X-ray bands of the electromagnetic spectrum heralds a new era in the study of the photoelectric effect. The unprecedented photon flux (~1013 photons per pulse) opens up to scrutiny processes with cross sections considered hitherto unfeasibly small to probe with conventional EUV sources such as synchrotrons and laser plasmas. The peak intensity of the focussed pulse train (<1013 W/cm2), combined with the high photon energy, ports non-linear optics and spectroscopy into a regime where inner shell electrons can become the predominant mediator of the photon matter interaction. Few photon, few electron photoionization processes are made amenable to study for the first time and the wavelength tunability of the FEL permits resonances to come into play. In combination with ultrafast optical lasers,...
http://doras.dcu.ie/111/
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Growth of CuCl thin films by magnetron sputtering for ultraviolet optoelectronic applications
(2006)
Natarajan, Gomathi; Daniels, Stephen; Cameron, D.C.; O'Reilly, Lisa; Mitra, Anirba...
Growth of CuCl thin films by magnetron sputtering for ultraviolet optoelectronic applications
(2006)
Natarajan, Gomathi; Daniels, Stephen; Cameron, D.C.; O'Reilly, Lisa; Mitra, Anirban; McNally, Patrick J.; Lucas, Francis Olabanji; Rajendra Kumar, R.T.; Reid, Ian; Bradley, Ann Louise
Abstract:
Copper (I) chloride (CuCl) is a potential candidate for ultraviolet (UV) optoelectronics due to its close lattice match with Si (mismatch less than 0.4%) and a high UV excitonic emission at room temperature. CuCl thin films were deposited using radio frequency magnetron sputtering technique. The influence of target to substrate distance (dts) and sputtering pressure on the composition, microstructure, and UV emission properties of the films were analyzed. The films deposited with shorter target to substrate spacing (dts=3 cm) were found to be nonstoichiometric, and the film stoichiometry improves when the substrate is moved away from the target (dts=4.5 and 6 cm). A further increase in the spacing results in poor crystalline quality. The grain interface area increases when the sputtering pressure is increased from 1.1×10–³ to 1×10–² mbar at dts=6 cm. Room temperature cathodoluminescence spectrum shows an intense and sharp UV exciton (Z₃) emission at ~385 nm with a full width at...
http://doras.dcu.ie/196/
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Electron heating mode transitions in dual frequency capacitive discharges
(2006)
Turner, Miles M.; Chabert, P.
Electron heating mode transitions in dual frequency capacitive discharges
(2006)
Turner, Miles M.; Chabert, P.
Abstract:
The authors consider electron heating in the sheath regions of capacitive discharges excited by a combination of two frequencies, one much higher than the other. There is a common supposition that in such discharges the higher frequency is the dominant source of electron heating. In this letter, the authors discuss closed analytic expressions quantifying the Ohmic and collisionless electron heating in a dual frequency discharge. In both cases, the authors show that the lower frequency parameters strongly influence the heating effect. Moreover, this influence is parametrically different, so that the dominant heating mechanism may be changed by varying the low frequency current density.
http://doras.dcu.ie/213/
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Kinetic properties of particle-in-cell simulations compromised by Monte Carlo collisions
(2006)
Turner, Miles M.
Kinetic properties of particle-in-cell simulations compromised by Monte Carlo collisions
(2006)
Turner, Miles M.
Abstract:
he particle-in-cell method with Monte Carlo collisions is frequently used when a detailed kinetic simulation of a weakly collisional plasma is required. In such cases, one usually desires, inter alia, an accurate calculation of the particle distribution functions in velocity space. However, velocity space diffusion affects most, perhaps all, kinetic simulations to some degree, leading to numerical thermalization (i.e., relaxation of the velocity distribution toward a Maxwellian), and consequently distortion of the true velocity distribution functions, among other undesirable effects. The rate of such thermalization can be considered a figure of merit for kinetic simulations. This article shows that, contrary to previous assumption, the addition of Monte Carlo collisions to a one-dimensional particle-in-cell simulation seriously degrades certain properties of the simulation. In particular, the thermalization time can be reduced by as much as three orders of magnitude. This effect mak...
http://doras.dcu.ie/214/
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Topological Phase Transitions and Holonomies in the Dimer Model
(2009)
Nash, Charles; O'Connor, Denjoe
Topological Phase Transitions and Holonomies in the Dimer Model
(2009)
Nash, Charles; O'Connor, Denjoe
Abstract:
We demonstrate that the classical dimer model defined on a toroidal hexagonal lattice acquires holonomy phases in the thermodynamic limit. When all activities are equal the lattice sizes must be considered mod 6 in which case the finite size corrections to the bulk partition function correspond to a massless Dirac Fermion in the presence of a flat connection with nontrivial holonomy. For general bond activities we find that the phase transition in this model is a topological one, where the torus degenerates and its modular parameter becomes real at the critical temperature. We argue that these features are generic to bipartite dimer models and we present a more general lattice whose continuum partition function is that of a massive Dirac Fermion.
http://eprints.nuim.ie/1567/
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