336 research outputs found
Deterministic cavity quantum electrodynamics with trapped ions
We have employed radio-frequency trapping to localize a single 40Ca+-ion in a high-finesse optical cavity. By means of laser Doppler cooling, the position spread of the ion's wavefunction along the cavity axis was reduced to 42 nm, a fraction of the resonance wavelength of ionized calcium (λ = 397 nm). By controlling the position of the ion in the optical field, continuous and completely deterministic coupling of ion and field was realized. The precise three-dimensional location of the ion in the cavity was measured by observing the fluorescent light emitted upon excitation in the cavity field. The single-ion system is ideally suited to implement cavity quantum electrodynamics under cw conditions. To this end we operate the cavity on the D3/2âP1/2 transition of 40Ca+ (λ = 866 nm). Applications include the controlled generation of single-photon pulses with high efficiency and two-ion quantum gates
First record of Bengal reticulated puffer Chelonodontops bengalensis (Tetraodontiformes: Tetraodontidae) from Odisha coast, north-western Bay of Bengal with taxonomic notes
The present study reports the first record of Bengal reticulated puffer, Chelonodontops bengalensis from Odisha coast in the north-western Bay of Bengal based on two specimens (226 â 301 mm SL), each collected from Paradeep and Bahabalpur in 2018 and 2019, respectively. The detailed morphological features of C. bengalensis are provided and compared with its previous records. The species is distinguished from its congeners by having 12 dorsal fin rays, 10 anal fin rays, 18 â 19 pectoral fin rays, 10 â 11 caudal fin rays, nasal organ cup shaped with unequal sized flaps, and dorsal profile of body covered with white spots of various shape and size and ventral side silvery white. Our study indicated the range extension of C. bengalensis from its known geographical range i.e. Bangladesh and West Bengal towards south in the northern Bay of Bengal
Magnetic and transport properties of the new antiferromagnetic Kondo-lattice CeNiBi2
We report results of the first studies on the magnetic and transport
properties of a new material CeNiBi_2. The magnetic susceptibility exhibits a
sharp peak at T_N = 6K, indicating an antiferromagnetic phase transition. This
antiferromagnetic order below T_N is confirmed by magnetization measurement,
which displays a metamagnetic-like transition at H_m = 5 T. Both
low-temperature susceptibility and high-field magnetization are suggestive of
strong crystalline-electric-field effect in CeNiBi_2. The electrical
resistivity shows the presence of Kondo and crystal-field effects with a sharp
drop below TN due to the antiferromagnetic ordering. This sharp drop below T_N
in the electrical resistivity is suppressed slightly to higher temperatures by
an applied magnetic field to 18 T. With increasing magnetic field, the slope of
magnetoresistance changes from positive to negative, being indicative of the
transition to a ferromagnetic state.Comment: 11 pages, including 4 figure
Dilatonic Black Holes in Higher Curvature String Gravity
We give analytical arguments and demonstrate numerically the existence of
black hole solutions of the Effective Superstring Action in the presence
of Gauss-Bonnet quadratic curvature terms. The solutions possess non-trivial
dilaton hair. The hair, however, is of ``secondary" type", in the sense that
the dilaton charge is expressed in terms of the black hole mass. Our solutions
are not covered by the assumptions of existing proofs of the ``no-hair"
theorem. We also find some alternative solutions with singular metric
behaviour, but finite energy. The absence of naked singularities in this system
is pointed out.Comment: 22 pages, Latex file, 7 Latex figures already include
Estimating Small Area Income Deprivation: An Iterative Proportional Fitting Approach
Small area estimation and in particular the estimation of small area income deprivation has
potential value in the development of new or alternative components of multiple deprivation
indices. These new approaches enable the development of income distribution threshold based
as opposed to benefit count based measures of income deprivation and so enable the
alignment of regional and national measures such as the Households Below Average Income
with small area measures. This paper briefly reviews a number of approaches to small area
estimation before describing in some detail an iterative proportional fitting based spatial
microsimulation approach. This approach is then applied to the estimation of small area HBAI
rates at the small area level in Wales in 2003-5. The paper discusses the results of this
approach, contrasts them with contemporary âofficialâ income deprivation measures for the
same areas and describes a range of ways to assess the robustness of the results
Density Functional Theory of Bosons in a Trap
A time-dependent Kohn-Sham (KS) like theory is presented for N bosons in thre
e and lower-dimensional traps. We derive coupled equations, which allow one to
calculate the energies of elementary excitations. A rigorous proof is given to
show that the KS like equation correctly describes properties of the
one-dimensional condensate of impenetrable bosons in a general time-dependent
harmonic trap in the larg N limit.Comment: 10 page
Vortices and domain walls in a Chern-Simons theory with magnetic moment interaction
We study the structure and properties of vortices in a recently proposed
Abelian Maxwell-Chern-Simons model in dimensions. The model which is
described by gauge field interacting with a complex scalar field, includes two
parity and time violating terms: the Chern-Simons and the anomalous magnetic
terms. Self-dual relativistic vortices are discussed in detail. We also find
one dimensional soliton solutions of the domain wall type. The vortices are
correctly described by the domain wall solutions in the large flux limit.Comment: To be published in Phys RevD 23 pages, RevTex, 5 figure
Photoionisation loading of large Sr+ ion clouds with ultrafast pulses
This paper reports on photoionisation loading based on ultrafast pulses of
singly-ionised strontium ions in a linear Paul trap. We take advantage of an
autoionising resonance of Sr neutral atoms to form Sr+ by two-photon absorption
of femtosecond pulses at a wavelength of 431nm. We compare this technique to
electron-bombardment ionisation and observe several advantages of
photoionisation. It actually allows the loading of a pure Sr+ ion cloud in a
low radio-frequency voltage amplitude regime. In these conditions up to 4x10^4
laser-cooled Sr+ ions were trapped
Spin correlated interferometry for polarized and unpolarized photons on a beam splitter
Spin interferometry of the 4th order for independent polarized as well as
unpolarized photons arriving simultaneously at a beam splitter and exhibiting
spin correlation while leaving it, is formulated and discussed in the quantum
approach. Beam splitter is recognized as a source of genuine singlet photon
states. Also, typical nonclassical beating between photons taking part in the
interference of the 4th order is given a polarization dependent explanation.Comment: RevTeX, 19 pages, 1 ps figure, author web page at
http://m3k.grad.hr/pavici
Open su(4)-invariant spin ladder with boundary defects
The integrable su(4)-invariant spin-ladder model with boundary defect is
studied using the Bethe ansatz method. The exact phase diagram for the ground
state is given and the boundary quantum critical behavior is discussed. It
consists of a gapped phase in which the rungs of the ladder form singlet states
and a gapless Luttinger liquid phase. It is found that in the gapped phase the
boundary bound state corresponds to an unscreened local moment, while in the
Luttinger liquid phase the local moment is screened at low temperatures in
analogy to the Kondo effect.Comment: Revtex 9 pages, published in PR
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