Christopher Smeenk

Learn More
We address the question of whether it is possible to operate a time machine by manipulating matter and energy so as to manufacture closed timelike curves. This question has received a great deal of attention in the physics literature, with attempts to prove no-go theorems based on classical general relativity and various hybrid theories serving as steps(More)
  • Christian Wüthrich, Phil Dowe, John Earman, Arthur Fine, Brian Hepburn, John Norton +2 others
  • 2003
Recently, many physicists have published on a topic that their predecessors ruminated over only on weekends: time travel and time machines. Most of these publications concern the prospect of time travel or of time machines in classical general relativity. A smaller number investigates the same issues in quantum gravity and quantum field theory. For the(More)
We apply tomography, a general method for reconstructing 3-D distributions from multiple projections, to reconstruct the momentum distribution of electrons produced via strong field photoionization. The projections are obtained by rotating the electron distribution via the polarization of the ionizing laser beam and recording a momentum spectrum at each(More)
The short-lived longitudinal plasma oscillations generated during filamentation in argon and nitrogen gas are measured with a specially designed current monitor. The magnitude and initial direction of the corresponding currents depend sensitively on laser polarization and nature of the gas. The results are interpreted as resulting from the competition(More)
Accurate imaging is a prerequisite for adaptive radiation therapy of mobile tumours. We present an evaluation of the performance of slow computed tomography (CT) for mapping and delineating the excursion boundary of a moving object using a tumour phantom scanned with the helical MVCT scanner of a tomotherapy unit. A spherical test object driven by(More)
  • 1