1,271 research outputs found
Experimental Test of Quantum No-Hiding Theorem
Linearity and unitarity are two fundamental tenets of quantum theory. Any
consequence that follows from these must be respected in the quantum world. The
no-cloning theorem and the no-deleting theorem are the consequences of the
linearity and the unitarity. Together with the stronger no-cloning theorem they
provide permanence to quantum information, thus, suggesting that in the quantum
world information can neither be created nor be destroyed. In this sense
quantum information is robust, but at the same time it is also fragile because
any interaction with the environment may lead to loss of information. Recently,
another fundamental theorem was proved, namely, the no-hiding theorem that
addresses precisely the issue of information loss. It says that if any physical
process leads to bleaching of quantum information from the original system,
then it must reside in the rest of the universe with no information being
hidden in the correlation between these two subsystems. This has applications
in quantum teleportation, state randomization, private quantum channels,
thermalization and black hole evaporation. Here, we report experimental test of
the no-hiding theorem with the technique of nuclear magnetic resonance (NMR).
We use the quantum state randomization of a qubit as one example of the
bleaching process and show that the missing information can be fully recovered
up to local unitary transformations in the ancilla qubits. Since NMR offers a
way to test fundamental predictions of quantum theory using coherent control of
quantum mechanical nuclear spin states, our experiment is a step forward in
this direction.Comment: 12 pages, 6 Figs. Jharana Rani Samal, Deceased on her 27th birthday
12th Nov. 2009. The experimental work of this paper was completely carried
out by the first author. We dedicate this paper to the memory of the
brilliant soul of Ms. Jharana Rani Samal
Implementasi Pendidikan Karakter di Sekolah dan Perguruan Tinggi melalui Pembelajaran Aktif
Berbagai pendekatan dan metode digunakan dalam pembelajaran aktif sehingga melahirkan istilah-istilah seperti pembelajaran berpusat pada siswa (student-centered learning), pembelajaran yang diatur sendiri (self-regulated learning), pembelajaran kolaboratif (collaborative learning), pembelajaran untuk belajar (learning to learn), pembelajaran berbasis masalah (problem based learning), pembelajaran berbasis inkuiri (inquiry based learning) yang kesemuanya mengharapkan siswa terlibat secara aktif dalam pembelajaran mereka sendiri
Deep GeMS/GSAOI near-infrared observations of N159W in the Large Magellanic Cloud
Aims. The formation and properties of star clusters at the edge of H II
regions are poorly known, partly due to limitations in angular resolution and
sensitivity, which become particularly critical when dealing with extragalactic
clusters. In this paper we study the stellar content and star-formation
processes in the young N159W region in the Large Magellanic Cloud.
Methods. We investigate the star-forming sites in N159W at unprecedented
spatial resolution using JHKs-band images obtained with the GeMS/GSAOI
instrument on the Gemini South telescope. The typical angular resolution of the
images is of 100 mas, with a limiting magnitude in H of 22 mag (90 percent
completeness). Photometry from our images is used to identify candidate young
stellar objects (YSOs) in N159W. We also determine the H-band luminosity
function of the star cluster at the centre of the H II region and use this to
estimate its initial mass function (IMF).
Results. We estimate an age of 2 + or - 1 Myr for the central cluster, with
its IMF described by a power-law with an index of gamma = - 1.05 + or - 0.2 ,
and with a total estimated mass of 1300 solar mass. We also identify 104
candidate YSOs, which are concentrated in clumps and subclusters of stars,
principally at the edges of the H II region. These clusters display signs of
recent and active star-formation such as ultra-compact H II regions, and
molecular outflows. This suggests that the YSOs are typically younger than the
central cluster, pointing to sequential star-formation in N159W, which has
probably been influenced by interactions with the expanding H II bubble
Exploring Foundations of Time-Independent Density Functional Theory for Excited-States
Based on the work of Gorling and that of Levy and Nagy, density-functional
formalism for many Fermionic excited-states is explored through a careful and
rigorous analysis of the excited-state density to external potential mapping.
It is shown that the knowledge of the ground-state density is a must to fix the
mapping from an excited-state density to the external potential. This is the
excited-state counterpart of the Hohenberg-Kohn theorem, where instead of the
ground-state density the density of the excited-state gives the true many-body
wavefunctions of the system. Further, the excited-state Kohn-Sham system is
defined by comparing it's non-interacting kinetic energy with the true kinetic
energy. The theory is demonstrated by studying a large number of atomic
systems.Comment: submitted to J. Chem. Phy
Correction of distortion for optimal image stacking in Wide Field Adaptive Optics: Application to GeMS data
The advent of Wide Field Adaptive Optics (WFAO) systems marks the beginning
of a new era in high spatial resolution imaging. The newly commissioned Gemini
South Multi-Conjugate Adaptive Optics System (GeMS) combined with the infrared
camera Gemini South Adaptive Optics Imager (GSAOI), delivers quasi
diffraction-limited images over a field of 2 arc-minutes across. However,
despite this excellent performance, some variable residues still limit the
quality of the analyses. In particular, distortions severely affect GSAOI and
become a critical issue for high-precision astrometry and photometry. In this
paper, we investigate an optimal way to correct for the distortion following an
inverse problem approach. Formalism as well as applications on GeMS data are
presented.Comment: 10 pages, 6 figure
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