616 research outputs found
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Memory and microhistory of an Empire: domestic contexts in Roman Amheida, Egypt
Simulating a one-dimensional plasma
We describe a dynamical model of a one-dimensional plasma and present a simple algorithm for simulating the model on a computer. We use the algorithm to perform several numerical experiments that illustrate collective effects in plasma physics such as Debye screening and plasma
oscillations
Time asymmetry in a dynamical model of the one-dimensional ideal gas
We present a simple dynamical model of the one-dimensional ideal gas and show how it can be used to introduce a number of fundamental ideas in statistical mechanics. We use the model to illustrate the role of initial conditions in explaining time asymmetry and show that although the dynamical model is time-reversal invariant, the macroscopic behavior of the gas can be time-asymmetric if the initial conditions are chosen properly
Advanced action in classical electrodynamics
The time evolution of a charged point particle is governed by a second-order
integro-differential equation that exhibits advanced effects, in which the
particle responds to an external force before the force is applied. In this
paper we give a simple physical argument that clarifies the origin and physical
meaning of these advanced effects, and we compare ordinary electrodynamics with
a toy model of electrodynamics in which advanced effects do not occur.Comment: 12 pages, 5 figure
A toy model of electrodynamics in (1 + 1) dimensions
A model is presented that describes a scalar field interacting with a point particle in (1+1) dimensions. The model exhibits many of the same phenomena that appear in classical electrodynamics, such as radiation and radiation damping, yet has a much simpler mathematical structure. By studying these phenomena in a highly simplified model, the physical concepts involved may be more easily understood
Quantum field theory in (0 + 1) dimensions
We show that many of the key ideas of quantum field theory can be illustrated simply and straightforwardly by using toy models in (0 + 1) dimensions. Because quantum field theory in (0 + 1) dimensions is equivalent to quantum mechanics, these models allow us to use techniques from quantum mechanics to gain insight into quantum field theory. In addition, working in (0 + 1) dimensions considerably simplifies the mathematics, allowing the physical concepts involved to be exhibited more clearly
Laserlike and atomlike regimes in a one-atom laser
We consider a three-level model of a one-atom laser, and show that there are two limiting regimes of parameter space, one in which the system behaves like a conventional laser and one in which the system exhibits novel quantum properties. We show that in the first limiting regime, the model can be approximated by semiclassical laser theory, and in the second limiting regime the model can be approximated as an effective two-level atom. We also perform numerical simulations that confirm the limiting behaviors predicted by these approximate descriptions
Hidden variable theories and quantum nonlocality
We clarify the meaning of Bell's theorem and its implications for the construction of hidden variable theories by considering an example system consisting of two entangled spin-1/2 particles. Using this example, we present a simplified version of Bell's theorem and describe several hidden variable theories that agree with the predictions of quantum mechanics. These example theories clarify some subtle points, which are often misunderstood, regarding what it is that Bell's theorem actually establishes
Simulating a toy model of electrodynamics in (1 + 1) dimensions
We show how to simulate a toy model of electrodynamics in (1+1) dimensions and describe several numerical experiments. The toy model is much simpler than ordinary electrodynamics, but shares many of the same physical features. For example, there are analogs to the electric and magnetic fields, and these fields generate forces between charged particles and support freely propagating radiation. Unlike electrodynamics, however, the toy model is not Lorentz invariant, gives an attractive force between charges of the same sign, and yields a radiation reaction force that depends on the particle velocity
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