533 research outputs found
Entanglement witnessing in superconducting beamsplitters
We analyse a large class of superconducting beamsplitters for which the Bell
parameter (CHSH violation) is a simple function of the spin detector
efficiency. For these superconducting beamsplitters all necessary information
to compute the Bell parameter can be obtained in Y-junction setups for the
beamsplitter. Using the Bell parameter as an entanglement witness, we propose
an experiment which allows to verify the presence of entanglement in Cooper
pair splitters.Comment: 5 pages, 2 figures, accepted for publication in EP
Grand unification and enhanced quantum gravitational effects
In grand unified theories with large numbers of fields, renormalization
effects significantly modify the scale at which quantum gravity becomes strong.
This in turn can modify the boundary conditions for coupling constant
unification, if higher dimensional operators induced by gravity are taken into
consideration. We show that the generic size of these effects from gravity can
be larger than the two-loop corrections typically considered in renormalization
group analyses of unification. In some cases, gravitational effects of modest
size can render unification impossible.Comment: 4 pages, 1 figure, revtex; minor changes in v2 (version published in
Phys. Rev. Lett.
Quantum gravity at a TeV and the renormalization of Newton's constant
We examine whether renormalization effects can cause Newton¿s constant to change dramatically with energy, perhaps even reducing the scale of quantum gravity to the TeV region without the introduction of extra dimensions. We examine a model that realizes this possibility and describe experimental signatures from the production of small black holes
Trade and Transportation Talent Pipeline Blueprints: Building UniversityIndustry Talent Pipelines in Colleges of Continuing and Professional Education
The rapid adoption of transformational technologies along with other economic and cultural shifts, have created a gap between workers and the skills and knowledge necessary for in-demand occupations. Trade and Transportation Talent Pipeline Blueprints: Building University-Industry Talent Pipelines in Colleges of Continuing and Professional Education identifies the steps required to build talent pipelines that target in-demand trade and transportation occupations requiring specific degrees, certificates, and non-credit professional development. This report provides a literature review and labor market data analysis. It also includes documentation of methodology in planning a pilot program for Colleges of Professional and Continuing Education housed within each of the 23 California State University campuses. The recommendations guide the colleges to develop talent pipelines to empower trade and transportation employers to play a more central role in addressing skills gaps and other critical workforce development needs in working partnerships with postsecondary education and training providers. The report concludes with a recommended university-industry Intelligent Transportation Systems (ITS) Talent Pipeline pilot program
Quantum Gravitational Effects and Grand Unification
In grand unified theories with large numbers of fields, renormalization
effects significantly modify the scale at which quantum gravity becomes strong.
This in turn can modify the boundary conditions for coupling constant
unification, if higher dimensional operators induced by gravity are taken into
consideration. We show that the generic size of, and the uncertainty in, these
effects from gravity can be larger than the two-loop corrections typically
considered in renormalization group analyses of unification. In some cases,
gravitational effects of modest size can render unification impossible.Comment: 3 pages, to appear in the proceedings of 16th International
Conference on Supersymmetry and Unification of Fundamental Interactions
(SUSY08), Seoul, Korea, June 16-21 200
Grand unification through gravitational effects
We systematically study the unification of gauge couplings in the presence of
(one or more) effective dimension-5 operators cHGG/4MPl, induced into the grand
unified theory by gravitational interactions at the Planck scale MPl. These
operators alter the usual condition for gauge coupling unification, which can,
depending on the Higgs content H and vacuum expectation value, result in
unification at scales MX significantly different than naively expected. We find
non-supersymmetric models of SU(5) and SO(10) unification, with natural Wilson
coefficients c, that easily satisfy the constraints from proton decay.
Furthermore, gauge coupling unification at scales as high as the Planck scale
seems feasible, possibly hinting at simultaneous unification of gauge and
gravitational interactions. In the Appendix we work out the group theoretical
aspects of this scenario for SU(5) and SO(10) unified groups in detail; this
material is also relevant in the analysis of non-universal gaugino masses
obtained from supergravity.Comment: 27 pages, 5 figures, 8 tables, 1 appendix, revtex; v2: introduction
and conclusion expanded, references added, minor changes, version published
in PR
What is the entropy of the universe?
Standard calculations suggest that the entropy of our universe is dominated
by black holes, whose entropy is of order their area in Planck units, although
they comprise only a tiny fraction of its total energy. Statistical entropy is
the logarithm of the number of microstates consistent with the observed
macroscopic properties of a system, hence a measure of uncertainty about its
precise state. Therefore, assuming unitarity in black hole evaporation, the
standard results suggest that the largest uncertainty in the future quantum
state of the universe is due to the Hawking radiation from evaporating black
holes. However, the entropy of the matter precursors to astrophysical black
holes is enormously less than that given by area entropy. If unitarity relates
the future radiation states to the black hole precursor states, then the
standard results are highly misleading, at least for an observer that can
differentiate the individual states of the Hawking radiation.Comment: 5 pages, 3 figures, 1 table, revtex; v3: revised and expanded
version, to appear in Class. Quant. Gra
Monsters, black holes and the statistical mechanics of gravity
We review the construction of monsters in classical general relativity.
Monsters have finite ADM mass and surface area, but potentially unbounded
entropy. From the curved space perspective they are objects with large proper
volume that can be glued on to an asymptotically flat space. At no point is the
curvature or energy density required to be large in Planck units, and quantum
gravitational effects are, in the conventional effective field theory
framework, small everywhere. Since they can have more entropy than a black hole
of equal mass, monsters are problematic for certain interpretations of black
hole entropy and the AdS/CFT duality.
In the second part of the paper we review recent developments in the
foundations of statistical mechanics which make use of properties of
high-dimensional (Hilbert) spaces. These results primarily depend on kinematics
-- essentially, the geometry of Hilbert space -- and are relatively insensitive
to dynamics. We discuss how this approach might be adopted as a basis for the
statistical mechanics of gravity. Interestingly, monsters and other highly
entropic configurations play an important role.Comment: 9 pages, 4 figures, revtex; invited Brief Review to be published in
Modern Physics Letters
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