Conveners
Theoretical and Computational Physics
- Alan Cornell (University of Johannesburg)
Theoretical and Computational Physics
- Aldo Deandrea (IPNL)
Theoretical and Computational Physics
- Azwinndini Muronga (Nelson Mandela University)
Theoretical and Computational Physics
- William Horowitz (University of Cape Town)
Theoretical and Computational Physics
- Thomas Konrad (UKZN)
Theoretical and Computational Physics
- Alan Cornell (University of Johannesburg)
Theoretical and Computational Physics
- Azwinndini Muronga (Nelson Mandela University)
Theoretical and Computational Physics
- Thomas Konrad (UKZN)
Theoretical and Computational Physics
- William Horowitz (University of Cape Town)
Theoretical and Computational Physics
- There are no conveners in this block
Theoretical and Computational Physics
- There are no conveners in this block
Theoretical and Computational Physics
- There are no conveners in this block
NMU-NITheCS Internship Programme is an annual summer study program in theoretical and computational sciences.
The internship research topics are under the overarching the subject: Matter Under Extreme Conditions in Heavy Ion Collisions and Astrophysics which is an inter-/trans-disciplinary subject as it is born at the borders between particle and nuclear physics, astrophysics, gravitation,...
We investigate whether quasinormal modes can be used in the search for signatures of extra dimensions. To address a gap in the literature, we focus on negative Ricci curvature extra dimensional spacetimes. Starting with a product space comprised of a four-dimensional Schwarzschild space-time and a 3-dimensional nilmanifold, we study the scalar perturbations. The geometry can be characterised...
The Weak Gravity Conjecture (WGC) is a theoretical conjecture that relates gravity to other forces within the framework of an Effective Field Theory (EFT). One of the primary motivations behind the WGC is to provide a kinematic constraint on the decay of extremal black holes. This kinematic constraint arises from the notion that the black hole must decay to states that are incapable of forming...
Dissipative systems are among the most interesting and challenging systems to study in physics. For instance, they require non-standard (i.e. complex) Lagrangians which include velocity-dependent potentials coupling the system of interest to another system (i.e. the environment). That is, a dissipative system can be thought of as a system that is coupled to another system. As such, studying...
In the wake of a perturbation, a black hole will radiate gravitational waves (GWs). After an initial response to the external stimulus, the GW spectrum of the perturbed black hole is dominated by a discrete set of complex quasinormal frequencies (QNFs) whose values depend exclusively on the characteristic black hole properties of mass, spin, and charge. For this reason, quasinormal modes...
The literature on the computation of black hole quasinormal modes (QNMs) is replete with the adoption of various approximation methods to solve the "quasi-Sturm Liouville" type problems governing the damped oscillations that dominate the ringdown phase of the time-evolving signal produced by perturbed black holes. Among the newest techniques is the physics-informed neural network (PINN)...
It is often said that Einstein's theory of gravity (GR) and quantum field theory (QFT) are incompatible. I will present an argument for this claim based on thermodynamic properties of black holes in asymptotically flat spacetime. Applying similar reasoning in anti-de Sitter spacetime suggests that in this case the theory of gravity in D dimensions could be compatible with a quantum field...
In this work, we present cosmological implications of viscous fluids vis-a-vis background expansion history and large-scale structure formation. The constrained cosmological and fluid parameters which are consistent with available data will first be provided, followed by the study of the growth of matter density fluctuations through the covariant cosmological perturbations formalism. Our...
I review quantum state monitoring and measurement-based feedback control at the example of a particle in a harmonic potential [1]. Feedback can be employed to effectively modify the Hamiltonian, dissipate energy and transfer the system into the ground state while simultaneously compensating the noise introduced by the continuous measurement.
[1] A.Rouillard, A. Reddy, H. Bassa, S. Maharaj,...
Using a study of the connection between entanglement and quantum detailed balance as motivation, we introduce the concept of balance between two quantum dynamical systems. The definition of a quantum dynamical system used is a von Neumann algebra with a faithful normal state, and a state preserving unital completely positive map. It is showed how balance can be used to find relaxed versions of...
Quantum mechanics, like any scientific theory, has a prevailing orthodoxy for its interpretation. However, due to the abstract nature of the formalism, interpretation of quantum theories is especially contentious. In this work we attempt to quantify the quantum orthodoxy via a systematic survey of popular graduate and undergraduate textbooks on the subject. In so doing, we determine the...
Topological behaviour in optical systems and low dimensional materials has been studied widely over the last several years. In materials topological states are of special interest as they promise to exhibit protected conducting surface states in otherwise insulating systems. The protection here refers to any symmetry-preserving perturbation to the system.
For rectangular lattices the 2D ...
Keywords: Advanced structural materials, First-principles calculations, Density functional theory (DFT), Phase stability and Phase transition
Abstract: The discovery of new advanced structural materials to meet the aggressive evolving engineering structural demands can be achieved through the integration of computational thermodynamics and validated experimental activities to...
Computer simulated study of the structural and electronic properties of β-MnO2 nanoclusters as cathode materials in rechargeable lithium-ion batteries
1,2 P.W. Masoga, 2P.E. Ngoepe and 2H.R. Chauke
1 University of Limpopo, Department of Mathematics, Science and Technology Education, School of Education, Private Bag x1106, Sovenga, 0727, South Africa
2 University of Limpopo, Materials...
We present a study of the equation of state in finite-temperature non-Abelian gauge theory for isotropic and anisotropic lattices, where the temperature $T$ is varied by changing the temporal lattice size $N_t$ at fixed lattice scale $a$. We compute the trace anomaly and the corresponding pressure/energy density and show the lattice spacing, as well as the volume dependence, with the...
We are interested in the effect of finite system size corrections to the QCD equation of state in heavy-ion collisions, to better understand the apparent formation of Quark Gluon Plasma in proton-nucleus and even proton-proton collisions. To do so, we need to build up the necessary understanding of Quantum Field Theories(QFTs) in finite systems.
To this end we derived for the first time the...
The standard model of particle physics has been used to successfully describe observables from particle collisions at high energies in colliders such as the LHC and RHIC. In the last twenty years evidence for the formation of a substance known as Quark Gluon Plasma (QGP), has been found in heavy-ion collisions (collisions of atoms with a large number of nucleons). This substance probes the...
Deep inelastic scattering (DIS) is a key measurement in nuclear physics. One of the massive advantages of DIS is that powerful mathematical theorems--known as factorization--have been proven. We discuss the application of these theorems and effective field theory to collisions between electrons and protons and the potential extension of these theorems to collisions between electrons and...
Open quantum Brownian motion (OQBM) represents a new type of Brownian motion with an additional quantum internal degree of freedom. This framework was introduced by Bauer, Bernard, and Tilloy [1] as a scaling limit of discrete-time open quantum walks [2,3]. Sinayskiy and Petruccione (SP) have shown that OQBM can be derived from the microscopic Hamiltonian of the system, bath, and system bath...
Topological properties of physical systems have been studied for many years for their robustness against environmental disturbances which leave these properties unchanged. In the context of magnetic systems, a topology that has been extensively investigated is that of the skyrmion where it has been shown to provide some utility for use in low-power, information storage and computing. More...
Quantum ghost imaging is a non-invasive imaging technique that involves non-local photon pairs. One photon from an entangled pair interacts with the object while the other non-integrating photon is directed to a spatially resolved imaging detector. In this context, the analysis of the spatial correlations of these two spatially separated photons enables the...
The theoretical and computational division meeting
We compute first principles calculations to characterize four types of point defects in the 2-dimensional material graphane. The point defects we consider in this contribution are nitrogen dopant-vacancy complexes and their various charge states. We compute the formation energies, binding energies, U-parameters and other electronic properties of these impurity-vacancy complexes in graphane...
Doping monometallic nanoclusters with other transition metal atoms have received significant attention since they can be rationally designed and integrated to achieve unique properties and functions. These properties are suitable for use in applications such as catalysis, microelectronics and nanotechnology. In this study, a density function theory approach was employed to investigate the...
The project explores the interlinked of biophysics, biomathematics and biostatistics; and further examine the application of deterministic models in biological systems using COVID-19 as a case study. The deterministic model, which utilizes the classical SEIR epidemic modeling framework, is used to determine the transmission dynamics of the COVID-19 epidemic. The objective of the project is to...
The impact parameter dependence (b = 0 – 19%) of different meson and baryon species at central rapidity and particle ratios in Pb+Pb was studied employing High Energy Heavy-Ion collisions at an incident kinetic beam energy (lab frame) of Eelb = 300 AGeV for a duration of t = 400 fm/c. The Pb+Pb reaction was simulated from the Ultra-relativistic Quantum Molecular Dynamics model (UrQMD). We...
The dying Schrodinger cat is modeled in this study as a simple harmonic oscillator using the usual various steps of modeling. The formulated constitutive equation of the dying cat developed is a second order differential equation with physical constant coefficients which includes three crucial components: the damping constant, b, which represents the quantity of poison the cat is exposed to,...
