1,000,016 research outputs found
Reply to “Comment on ‘Microwave vortex dissipation of superconducting Nd-Ce-Cu-O epitaxial films in high magnetic fields’”
We demonstrate with detailed analysis that the criticisms in the preceding Comment by Blackstead are largely due to insufficient understanding of the experimental issues associated with our system or the imposition of formalism that is inapplicable to our experiments. In particular, we distinguish the conventional formalism for “field-defined” surface resistance applicable to measurements on samples with filling factors i.e., the ratio of the sample volume to that of the microwave cavity approaching 1 from our “dissipation-defined” surface resistance derived from first principles for measurements on samples with very small filling factors
A microfabricated ion trap with integrated microwave circuitry
We describe the design, fabrication and testing of a surface-electrode ion
trap, which incorporates microwave waveguides, resonators and coupling elements
for the manipulation of trapped ion qubits using near-field microwaves. The
trap is optimised to give a large microwave field gradient to allow
state-dependent manipulation of the ions' motional degrees of freedom, the key
to multiqubit entanglement. The microwave field near the centre of the trap is
characterised by driving hyperfine transitions in a single laser-cooled 43Ca+
ion.Comment: 4 pages, 5 figure
Note on exponential families of distributions
We show that an arbitrary probability distribution can be represented in
exponential form. In physical contexts, this implies that the equilibrium
distribution of any classical or quantum dynamical system is expressible in
grand canonical form.Comment: 5 page
On the Tidal Dissipation of Obliquity
We investigate tidal dissipation of obliquity in hot Jupiters. Assuming an
initial random orientation of obliquity and parameters relevant to the observed
population, the obliquity of hot Jupiters does not evolve to purely aligned
systems. In fact, the obliquity evolves to either prograde, retrograde or
90^{o} orbits where the torque due to tidal perturbations vanishes. This
distribution is incompatible with observations which show that hot jupiters
around cool stars are generally aligned. This calls into question the viability
of tidal dissipation as the mechanism for obliquity alignment of hot Jupiters
around cool stars.Comment: 6 pages, 4 figures, accepted at ApJ
Hydrodynamic theory of surface excitations of three-dimensional topological insulators
Edge excitations of a fractional quantum Hall system can be derived as
surface excitations of an incompressible quantum droplet using one dimensional
chiral bosonization. Here we show that an analogous approach can be developed
to characterize surface states of three-dimensional time reversal invariant
topological insulators. The key ingredient of our theory is the Luther's
multidimensional bosonization construction.Comment: 4 pages, published versio
Comparing verbal media for alarm handling: Speech versus textual displays
The rise of computers in command and control domains has meant that control operations can be performed via desk-based visual display terminals. This trend has also produced the potential to display information to operators in a variety of formats. Of particular interest has been the use of text-based displays for alarm presentation. There are possible limitations to the use of text for alarm presentation, not least of which is the need for a dedicated alarms display screen (or, at least, a display page). Given the capability of computers to synthesize speech, it is possible that speech-based alarms could generate the same information as text-based displays without the need for dedicated screen space. In this paper an experimental comparison of speech-based and text-based displays for presentation of alarms is reported. The findings show that speech leads to longer response times than text displays, but that it has minimal effect on the efficacy of fault handling. The results are discussed within the alarm initiated activities framework and implications for alarm system design are outlined
Injection locking of two frequency-doubled lasers with 3.2 GHz offset for driving Raman transitions with low photon scattering in Ca
We describe the injection locking of two infrared (794 nm) laser diodes which
are each part of a frequency-doubled laser system. An acousto-optic modulator
(AOM) in the injection path gives an offset of 1.6 GHz between the lasers for
driving Raman transitions between states in the hyperfine split (by 3.2 GHz)
ground level of Ca. The offset can be disabled for use in
Ca. We measure the relative linewidth of the frequency-doubled beams
to be 42 mHz in an optical heterodyne measurement. The use of both injection
locking and frequency doubling combines spectral purity with high optical
power. Our scheme is applicable for providing Raman beams across other ion
species and neutral atoms where coherent optical manipulation is required.Comment: 3 pages, 3 figure
Gauge Model With Extended Field Transformations in Euclidean Space
An SO(4) gauge invariant model with extended field transformations is
examined in four dimensional Euclidean space. The gauge field is
where are the SO(4) generators in the fundamental
representation. The SO(4) gauge indices also participate in the Euclidean space
SO(4) transformations giving the extended field transformations. We provide the
decomposition of the reducible field in terms of fields
irreducible under SO(4). The SO(4) gauge transformations for the irreducible
fields mix fields of different spin. Reducible matter fields are introduced in
the form of a Dirac field in the fundamental representation of the gauge group
and its decomposition in terms of irreducible fields is also provided. The
approach is shown to be applicable also to SO(5) gauge models in five
dimensional Euclidean space.Comment: 31 pages, Plain LaTe
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