11,089 research outputs found
Gravitational waves from Higgs domain walls
The effective potential for the Standard Model Higgs field allows two
quasi-degenerate vacua; one is our vacuum at the electroweak scale, while the
other is at a much higher scale. The latter minimum may be at a scale much
smaller than the Planck scale, if the potential is lifted by new physics. This
gives rise to a possibility of domain wall formation after inflation. If the
high-scale minimum is a local minimum, domain walls are unstable and disappear
through violent annihilation processes, producing a significant amount of
gravitational waves. We estimate the amount of gravitational waves produced
from unstable domain walls in the Higgs potential and discuss detectability
with future experiments.Comment: 15 pages, 3 figures; v2: title changed, comments and references
added; v3: accepted for publication in PL
Characterizing common cause closedness of quantum probability theories
We prove new results on common cause closedness of quantum probability
spaces, where by a quantum probability space is meant the projection lattice of
a non-commutative von Neumann algebra together with a countably additive
probability measure on the lattice. Common cause closedness is the feature that
for every correlation between a pair of commuting projections there exists in
the lattice a third projection commuting with both of the correlated
projections and which is a Reichenbachian common cause of the correlation. The
main result we prove is that a quantum probability space is common cause closed
if and only if it has at most one measure theoretic atom. This result improves
earlier ones published in Z. GyenisZ and M. Redei Erkenntnis 79 (2014) 435-451.
The result is discussed from the perspective of status of the Common Cause
Principle. Open problems on common cause closedness of general probability
spaces are formulated, where is an
orthomodular bounded lattice and is a probability measure on
.Comment: Submitted for publicatio
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