Quantum mechanics predicts only a certain level of nonlocality. So why is Nature not more nonlocal, i.e. superquantum? In principle, Nature could be perfectly nonlocal and still not allow faster-than-light signalling.
Analytical and numerical results are presented for models of a complex network exhibiting growth via preferential (Barabási-Albert model), random and a mixture of both preferential and random attachment.
Results of a Monte-Carlo simulation of a 10 by 10 Ising lattice are presented. The Metropolis dynamics in non-zero external field reveal metastability and hysteresis phenomena characteristic of permanent magnets.
The speed of light is one of Nature’s fundamental constants. It is pivotal to our understanding of space and time and is generally believed to restrict the speed at which information can be sent. But what exactly does it mean to have a maximum speed and why can’t it be exceeded, asks Paul Secular.
Recovery of the parameters and initial conditions of chaotic solutions to the Lorenz equations is attempted using genetic algorithms. For discrete sets of possible parameter values, a genetic algorithm is shown to converge faster on average than a brute force approach.
The probabilistic nature of radioactive decay is discussed and simulated via the “radioactive dice” experiment. The decay constant is examined and related to the probability of decay.
A satellite approaching the planet Mars is considered. Its equation of motion is derived and solved numerically in Cartesian and polar coordinates. The combined motion of planet and satellite is then considered and modelled using Jacobi coordinates.
A mass moves under gravity on a frictionless ramp, which rotates at a constant angular velocity. The object's equation of motion is derived and an expression is found for the condition under which the mass leaves the surface of the ramp.
There is still widespread confusion about what exactly the uncertainty principle is and what it describes. We shed some light on this, illustrating two distinct uncertainty relations stemming from Heisenberg's work.
A force-free mass is observed in free fall within a rotating frame of reference, leading to the appearance of “artificial gravity”. Expressions are derived for the object's equation of motion and its time of flight.
A mass moves under gravity on a curved ramp exhibiting friction. The Coulomb model of dry friction is assumed in order to derive the object's equation of motion and the work done against friction by the mass.
An introduction to chaos theory based on an undergraduate presentation given by Paul Secular at St. John's College, Oxford. The series L-R-varactor circuit is discussed as an example of a simple physical system exhibiting chaotic behaviour.