3,592 research outputs found
Vacuum decay via Lorentzian wormholes
We speculate about the spacetime description due to the presence of
Lorentzian wormholes (handles in spacetime joining two distant regions or other
universes) in quantum gravity. The semiclassical rate of production of these
Lorentzian wormholes in Reissner-Nordstr\"om spacetimes is calculated as a
result of the spontaneous decay of vacuum due to a real tunneling
configuration. In the magnetic case it only depends on the field theoretical
fine structure constant. We predict that the quantum probability corresponding
to the nucleation of such geodesically complete spacetimes should be actually
negligible in our physical Universe
Spin-phonon induced magnetic order in Kagome ice
We study the effects of lattice deformations on the Kagome spin ice, with
Ising spins coupled by nearest neighbor exchange and long range dipolar
interactions, in the presence of in-plane magnetic fields. We describe the
lattice energy according to the Einstein model, where each site distortion is
treated independently. Upon integration of lattice degrees of freedom,
effective quadratic spin interactions arise. Classical MonteCarlo simulations
are performed on the resulting model, retaining up to third neighbor
interactions, under different directions of the magnetic field. We find that,
as the effect of the deformation is increased, a rich plateau structure appears
in the magnetization curves.Comment: 7 pages, 8 figure
Spin-Peierls-like phases in magnetoelastic antiferromagnetic chain at 1/3 magnetization
We investigate elastic deformations of spin antiferromagnetic
Heisenberg chains, at magnetization, coupled to phonons in
the adiabatic approximation. Using a bosonization approach we predict the
existence of non-homogeneous trimerized magnetoelastic phases. A rich ground
state phase diagram is found, including classical and quantum plateau states
for the magnetic sector as well as inequivalent lattice deformations within
each magnetic phase. The analytical results are supported by exact
diagonalization of small clusters.Comment: 7 pages, 5 figure
Analyzing Extreme Programming and B-Trees with Sail
The emulation of Boolean logic is an unproven issue. Given the current status of metamorphic methodologies, hackers worldwide famously desire the evaluation of SMPs, which embodies the technical principles of complexity theory. In order to overcome this grand challenge, we propose a novel method for the development of expert systems (Sail), which we use to verify that randomized algorithms can be made symbiotic, “smart”, and concurrent
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