Research Articles (Physics)
Recent Submissions

Snake fangs : 3D morphological and mechanical analysis by microCT, simulation, and physical compression testing
(Oxford University Press, 2018)This Data Note provides data from an experimental campaign to analyse the detailed internal and external morphology and mechanical properties of venomous snake fangs. The aim of the experimental campaign was to investigate ...

Emerging translational variance : vacuum polarization energy of the 𝜙6 kink
(Hindawi, 20170730)We propose an efficient method to compute the vacuum polarization energy of static field configurations that do not allow decomposition into symmetric and antisymmetric channels in one space dimension. In particular, we ...

Simple models of three coupled PTsymmetric wave guides allowing for thirdorder exceptional points
(Czech Technical UniversityPrague, 201708)We study theoretical models of three coupled wave guides with a PTsymmetric distribution of gain and loss. A realistic matrix model is developed in terms of a threemode expansion. By comparing with a previously postulated ...

Proportional crosstalk for the iThemba LABS clover detector
(Jagiellonian University, 201703)Measurements of the proportional crosstalk were performed for the iThemba LABS segmented clover detector. More than 1000 crosstalk parameters were determined and a crosstalk correction algorithm was implemented successfully.

Chiral bands in 193Tl
(Jagiellonian University, 201703)Since the introduction of chirality in nuclei, the search for chiral candidates in different mass regions has been a hot topic for about two decades. At iThemba LABS, a new chiral symmetry region, the thallium isotopes with ...

Spectroscopy of low lying states in 136Cs
(IOP Publishing, 2016)The lowlying excited states in 136Cs relevant to the double beta decay of 136Xe were studied via a 138Ba(d, α)136Cs transfer reaction with a high resolution magnetic spectrometer. Preliminary results from the experiment ...

Distortedwave Born approximation study of the 11Li(p,t) 9Li reaction
(IOP Publishing, 2016)The reaction 11Li(p,t) 9Li(gs) at an incident energy of 4 MeV is treated in terms of a simplistic distortedwave Born approximation transfer. The halo neutrons involved in the reaction are treated as a dineutron cluster ...

Diffusions conditioned on occupation measures
(AIP, 201602)A Markov process fluctuating away from its typical behavior can be represented in the longtime limit by another Markov process, called the effective or driven process, having the same stationary states as the original ...

An overview of the first decade of PollyNET : an emerging network of automated Ramanpolarization lidars for continuous aerosol profiling
(Copernicus Publications on behalf of the European Geosciences Union, 2016)The paper gives an overview of the observations on four continents and two research vessels obtained with eight Polly systems. The specific aerosol types at these locations (mineral dust, smoke, dustsmoke and other dusty ...

Laboratory Xray microcomputed tomography : a user guideline for biological samples
(Oxford University Press, 2015)Laboratory Xray microcomputed tomography (microCT) is a fast growing method in scientific research applications that allows for nondestructive imaging of morphological structures. This paper provides an easily operated ...

Defectinduced supersolidity with softcore bosons
(Nature Publishing Group, 2014)More than 40 years ago, Andreev, Lifshitz and Chester suggested the possible existence of a peculiar solid phase of matter, the microscopic constituents of which can flow superfluidly without resistance due to the formation ...

Selfhealing of quantum entanglement after an obstruction
(Nature Publishing Group, 2014)Quantum entanglement between photon pairs is fragile and can easily be masked by losses in transmission path and noise in the detection system. When observing the quantum entanglement between the spatial states of photon ...

Heavy baryons with strangeness in a soliton model
(Elsevier, 201509)We present results from a chiral soliton model calculation for the spectrum of baryons with a single heavy quark (charm or bottom) and nonzero strangeness. We treat the strange components within a three flavor collective ...

Galactic production of 138La : Impact of 138,139La statistical properties
(Elsevier, 2015)The γray strength functions and nuclear level densities of 138La and 139La have been measured below the neutron separation energies. These new data were used to calculate astrophysical Maxwellianaveraged (n, γ) crosssections ...

Process tomography via sequential measurements on a single quantum system
(American Physical Society, 20150903)We utilize a discrete (sequential) measurement protocol to investigate quantum process tomography of a single twolevel quantum system, with an unknown initial state, undergoing Rabi oscillations. The ignorance of ...

Interplay of soundcone and supersonic propagation in lattice models with power law interactions
(Bristol : IOP Publishing, 20150616)Westudy the spreading of correlations and other physical quantities in quantum lattice models with interactions or hopping decaying like r−α with the distance r.Our focus is on exponents α between 0 and 6, where the ...

Entanglementenhanced spreading of correlations
(IOP Publishing, 20151217)Starting from a product initial state, equaltime correlations in nonrelativistic quantum lattice models propagate within a light conelike causal region. The presence of entanglement in the initial state can modify this ...

Duality constructions from quantum state manifolds
(Springer, 20151120)The formalism of quantum state space geometry on manifolds of generalised coherent states is proposed as a natural setting for the construction of geometric dual descriptions of nonrelativistic quantum systems. These state ...

Potential energy landscape of the twodimensional XY model: Higherindex stationary points
(AIP Publishing LLC, 20140612)The application of numerical techniques to the study of energy landscapes of large systems relies on sufficient sampling of the stationary points. Since the number of stationary points is believed to grow exponentially ...

Higherorder interference and singlesystem postulates characterizing quantum theory
(Institute of Physics, 20141210)We present a new characterization of quantum theory in terms of simple physical principles that is different from previous ones in two important respects: first, it only refers to properties of single systems without any ...

Exchangeinduced crystallization of softcore bosons
(Institute of Physics, 20140328)We study the phase diagram of a twodimensional assembly of bosons interacting via a softcore repulsive pair potential of varying strength, and compare it to that of the equivalent system in which particles are regarded ...

Ultrafast dynamics of excitons in tetracene single crystals
(AIP Publishing LLC, 20140318)Ultrafast exciton dynamics in free standing 200 nm thin tetracene single crystals were studied at room temperature by femtosecond transient absorption spectroscopy in the visible spectral range. The complex spectrally ...

White light wavefront control with a spatial light modulator
(Optical Society of America, 201405)Spatial light modulators are ubiquitous tools for wavefront control and laser beam shaping but have traditionally been used with monochromatic sources due to the inherent wavelength dependence of the calibration process ...

Relaxation timescales and decay of correlations in a longrange interacting quantum simulator
(IOP, 2013)We study the time evolution of correlation functions in longrange interacting quantum Ising models. For a large class of initial conditions, exact analytic results are obtained in arbitrary lattice dimension, both for ...

Internal cumulants for femtoscopy with fixed charged multiplicity
(Hindawi Publishing Corporation, 2013)A detailed understanding of all effects and influences on higherorder correlations is essential. At low charged multiplicity, the effect of a nonPoissonian multiplicity distribution can significantly distort correlations. ...

Spinning pipe gas lens aberrations along the axis and in the boundary layer
(Academy of Science of South Africa, 20131125)When the walls of an openended horizontal steel pipe are heated before the pipe is rotated along its axis, the exchange of the expelled heated air with the incoming cooler air, sucked in along the axis, results in a medium ...

Nonperturbative flow equations from running expectation values
(American Physical Society (APS), 200308)We show that Wegner’s flow equations, as recently discussed in the Lipkin model, can be solved selfconsistently. This leads to a nonlinear differential equation which fully determines the order parameter as a function ...

Influence of gas discharge parameters on emissions from a dielectric barrier discharge excited argon excimer lamp
(ASSAF  Academy of Science of South Africa, 201111)A dielectric barrier discharge excited neutral argon (Ar I) excimer lamp has been developed and characterised. The aim of this study was to develop an excimer lamp operating at atmospheric pressure that can replace mercury ...

Internet access constrains science development and training at South African universities
(Academy of Science of South Africa (ASSAf), 201109)As a group of young scientists whose future careers depend increasingly on access to Internet resources, we are extremely concerned by the apparent lack of understanding of the stranglehold that current approaches to ...

Femtosecond pump probe spectroscopy for the study of energy transfer of lightharvesting complexes from extractions of spinach leaves
(Academy of Science of South Africa (ASSAf), 200910)Measurements of ultrafast transient processes, of temporal durations in the picosecond and femtosecond regime, are made possible by femtosecond pump probe transient absorption spectroscopy. Such an ultrafast pump probe ...