11,384 research outputs found
CKM Reach at Hadronic Colliders
The analysis of the CKM parameters will take a leap forward when the hadronic
B factories receive their first data. I describe the challenges faced by
B-physics at hadronic colliders and the expected reach in specific channels for
the LHCb, BTeV, ATLAS and CMS experiments.Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP
Durham, April 2003 (eConf C0304052). 6 pages LaTeX, 6 eps file
Quantum excitation-free radiation emission including multiple scattering
In order to increase the luminosity of electron-positron colliders it is
desirable to find a means to reduce the phase-space of the beams. The
transverse cooling of positrons imposed by the quantum excitation-free
radiation emission in a single crystal is considered as a potential route to
achieving ultra-cold beams. An analysis of the problem is presented, including
an evaluation of the contribution from multiple scattering during the passage.
The analysis shows that an emittance reduction may be achieved in special
cases, but in general the emittance will increase as a result of the multiple
scattering.Comment: Presented at the 3rd Workshop on Quantum Aspects of Beam Physics,
Hiroshima 200
The real projective spaces in homotopy type theory
Homotopy type theory is a version of Martin-L\"of type theory taking
advantage of its homotopical models. In particular, we can use and construct
objects of homotopy theory and reason about them using higher inductive types.
In this article, we construct the real projective spaces, key players in
homotopy theory, as certain higher inductive types in homotopy type theory. The
classical definition of RP(n), as the quotient space identifying antipodal
points of the n-sphere, does not translate directly to homotopy type theory.
Instead, we define RP(n) by induction on n simultaneously with its tautological
bundle of 2-element sets. As the base case, we take RP(-1) to be the empty
type. In the inductive step, we take RP(n+1) to be the mapping cone of the
projection map of the tautological bundle of RP(n), and we use its universal
property and the univalence axiom to define the tautological bundle on RP(n+1).
By showing that the total space of the tautological bundle of RP(n) is the
n-sphere, we retrieve the classical description of RP(n+1) as RP(n) with an
(n+1)-cell attached to it. The infinite dimensional real projective space,
defined as the sequential colimit of the RP(n) with the canonical inclusion
maps, is equivalent to the Eilenberg-MacLane space K(Z/2Z,1), which here arises
as the subtype of the universe consisting of 2-element types. Indeed, the
infinite dimensional projective space classifies the 0-sphere bundles, which
one can think of as synthetic line bundles.
These constructions in homotopy type theory further illustrate the utility of
homotopy type theory, including the interplay of type theoretic and homotopy
theoretic ideas.Comment: 8 pages, to appear in proceedings of LICS 201
Heisenberg modules as function spaces
Let be a closed, cocompact subgroup of , where
is a second countable, locally compact abelian group. Using localization of
Hilbert -modules, we show that the Heisenberg module
over the twisted group -algebra
due to Rieffel can be continuously and densely embedded into the Hilbert space
. This allows us to characterize a finite set of generators for
as exactly the generators of multi-window
(continuous) Gabor frames over , a result which was previously known
only for a dense subspace of . We show that
as a function space satisfies two properties that
make it eligible for time-frequency analysis: Its elements satisfy the
fundamental identity of Gabor analysis if is a lattice, and their
associated frame operators corresponding to are bounded.Comment: 24 pages; several changes have been made to the presentation, while
the content remains essentially unchanged; to appear in Journal of Fourier
Analysis and Application
Coupling single emitters to quantum plasmonic circuits
In recent years the controlled coupling of single photon emitters to
propagating surface plasmons has been intensely studied, which is fueled by the
prospect of a giant photonic non-linearity on a nano-scaled platform. In this
article we will review the recent progress on coupling single emitters to
nano-wires towards the construction of a new platform for strong light-matter
interaction. The control over such a platform might open new doors for quantum
information processing and quantum sensing at the nanoscale, and for the study
of fundamental physics in the ultra-strong coupling regime
Towards Interactive, Incremental Programming of ROS Nodes
Writing software for controlling robots is a complex task, usually demanding
command of many programming languages and requiring significant
experimentation. We believe that a bottom-up development process that
complements traditional component- and MDSD-based approaches can facilitate
experimentation. We propose the use of an internal DSL providing both a tool to
interactively create ROS nodes and a behaviour-replacement mechanism to
interactively reshape existing ROS nodes by wrapping the external interfaces
(the publish/subscribe topics), dynamically controlled using the Python command
line interface.Comment: Presented at DSLRob 2014 (arXiv:cs/1411.7148
- …