10,269 research outputs found
Understanding Popper's Experiment
An experiment proposed by Karl Popper is considered by many to be a crucial
test of quantum mechanics. Although many loopholes in the original proposal
have been pointed out, they are not crucial to the test. We use only the
standard interpretation of quantum mechanics to point out what is fundamentally
wrong with the proposal, and demonstrate that Popper's basic premise was
faulty.Comment: Edited version, to appear in Am. J. Phy
Mechanically reclaiming abandoned saline soils: a numerical evaluation
Water quality / Groundwater / Simulation models / Calibrations / Water table / Water balance / Hydraulics / Soil reclamation / Soil water / Flow / Soil properties / Salinity / Pakistan / Punjab / Sindh
Pechukas-Yukawa approach to the evolution of the quantum state of a parametrically perturbed system
We consider the evolution of a quantum state of a Hamiltonian which is
parametrically perturbed via a term proportional to the adiabatic parameter
\lambda (t). Starting with the Pechukas-Yukawa mapping of the energy
eigenvalues evolution on a generalised Calogero-Sutherland model of 1D
classical gas, we consider the adiabatic approximation with two different
expansions of the quantum state in powers of d\lambda/dt and compare them with
a direct numerical simulation. We show that one of these expansions (Magnus
series) is especially convenient for the description of non-adiabatic evolution
of the system. Applying the expansion to the exact cover 3-satisfability
problem, we obtain the occupation dynamics which provides insight on the
population of states.Comment: 12 pages, 6 figure
Twisted Poincar\'e Invariant Quantum Field Theories
It is by now well known that the Poincar\'e group acts on the Moyal plane
with a twisted coproduct. Poincar\'e invariant classical field theories can be
formulated for this twisted coproduct. In this paper we systematically study
such a twisted Poincar\'e action in quantum theories on the Moyal plane. We
develop quantum field theories invariant under the twisted action from the
representations of the Poincar\'e group, ensuring also the invariance of the
S-matrix under the twisted action of the group . A significant new contribution
here is the construction of the Poincar\'e generators using quantum fields.Comment: 17 pages, JHEP styl
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