638 research outputs found
Variable search for orientation, uniformly optimal search for identity.
This work was supported by the Economic and Social Research Council (ES/S016120/1 to Amelia R. Hunt, Principal Investigator, Alasdair D. F. Clarke Co-investigator). Additional support came from the James S. McDonnell Foundation (Scholar award to Amelia R. Hunt). The authors wish to extend their gratitude for the contribution of Jessica Christie, who collected and prepared the icon stimuli and collected the data for the first experiment. They also wish to thank Jacqueline von Seth for helping with piloting the experiments and additional data collection. Open Access funding provided by University of Leicester:Peer reviewe
Monitoring Entanglement Evolution and Collective Quantum Dynamics
We generalize a recently developed scheme for monitoring coherent quantum
dynamics with good time-resolution and low backaction [Reuther et al., Phys.
Rev. Lett. 102, 033602 (2009)] to the case of more complex quantum dynamics of
one or several qubits. The underlying idea is to measure with lock-in
techniques the response of the quantum system to a high-frequency ac field. We
demonstrate that this scheme also allows one to observe quantum dynamics with
many frequency scales, such as that of a qubit undergoing Landau-Zener
transitions. Moreover, we propose how to measure the entanglement between two
qubits as well as the collective dynamics of qubit arrays.Comment: 11 pages, 5 figure
Crystallographically oriented magnetic ZnFe2O4 nanoparticles synthesized by Fe implantation into ZnO
In this paper, a correlation between structural and magnetic properties of Fe
implanted ZnO is presented. High fluence Fe^+ implantation into ZnO leads to
the formation of superparamagnetic alpha-Fe nanoparticles. High vacuum
annealing at 823 K results in the growth of alpha-Fe particles, but the
annealing at 1073 K oxidized the majority of the Fe nanoparticles. After a long
term annealing at 1073 K, crystallographically oriented ZnFe2O4 nanoparticles
were formed inside ZnO with the orientation relationship of
ZnFe2O4(111)[110]//ZnO(0001)[1120]. These ZnFe2O4 nanoparticles show a
hysteretic behavior upon magnetization reversal at 5 K.Comment: 21 pages, 7 figures, accepted by J. Phys. D: Appl. Phy
Ground-state properties of the spin-1/2 antiferromagnetic Heisenberg model on the triangular lattice: A variational study based on entangled-plaquette states
We study, on the basis of the general entangled-plaquette variational ansatz,
the ground-state properties of the spin-1/2 antiferromagnetic Heisenberg model
on the triangular lattice. Our numerical estimates are in good agreement with
available exact results and comparable, for large system sizes, to those
computed via the best alternative numerical approaches, or by means of
variational schemes based on specific (i.e., incorporating problem dependent
terms) trial wave functions. The extrapolation to the thermodynamic limit of
our results for lattices comprising up to N=324 spins yields an upper bound of
the ground-state energy per site (in units of the exchange coupling) of
[ for the XX model], while the estimated
infinite-lattice order parameter is (i.e., approximately 64% of the
classical value).Comment: 8 pages, 3 tables, 2 figure
Investigation of molecular dimers by ensemble and single molecule spectroscopy
We have investigated molecular dimers with different electronic coupling strengths by bulk and single molecule spectroscopy. In one of the dimers the two monomers (perylene-monoimide) are directly connected via a single bond while in the other one they are separated by the benzil motif. The close proximity of the monomers in the first case gives rise to excitonic band splitting which is clearly observable in the bulk absorption spectra. For the benzil structure the electronic interactions are governed by Förster-type energy hopping between the monomers. Fluorescence intensity trajectories at the single molecule level show one-step and two-step bleaching behaviour which appears to be very similar for both dimers. However, emission spectra recorded simultaneously with the trajectories indicate spectral changes which allow to distinguish between weakly and strongly coupled dimers. In the latter case the spectral shape changes significantly when excitonic coupling has been lifted because of photochemical transformation of one of the monomers
THE RESPONSE OF YOUNG VALENCIA ORANGE TREES TO DIFFERENTIAL BORON SUPPLY IN SAND CULTURE
MINERAL COMPOSITION OF CHLOROTIC ORANGE LEAVES AND SOME OBSERVATIONS ON THE RELATION OF SAMPLE PREPARATION TECHNIQUE TO THE INTERPRETATION OF RESULTS
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