269 research outputs found
Qutrit state engineering with biphotons
The novel experimental realization of three-level optical quantum systems is
presented. We use the polarization state of biphotons to generate a specific
sequence of states that are used in the extended version of BB84 protocol. We
experimentally verify the orthogonality of the basis states and demonstrate the
ability to easily switch between them. The tomography procedure is employed to
reconstruct the density matrices of generated states.Comment: 5 pages, 4 figures. typos correcte
Multivariable power least squares method. Complementary tool for response surface methodology
In Response Surface Methodology (RSM), variables are correlated through polynomial functions based on Stone-Weierstrass theorem. However, such formulation inherits four weaknesses: possible misleading approximation, incapability to accurately determine the ranking of factors' dominance, failure to analyse factors in random value and proliferation of guess functions due to Pascal Triangle. Therefore, this article aims to develop an improvised method to rectify and complement the weaknesses of RSM. Multivariable Power Least Squares Method (MPLSM) has been developed to correlate various sets of independent variables with dependent variable in the form of power functions. MPLSM is built upon least squares method, and able to approximate the indices of the variables easily. Two variants of MPLSM are suggested to further ensure the numerical stability: the Normalised MPLSM and Iterative MPLSM. The proposed method is not only substantial in big data analysis and multivariable problems, but also providing an alternative approach in engineering optimisation
Statistical Reconstruction of Qutrits
We discuss a procedure of measurement followed by the reproduction of the
quantum state of a three-level optical system - a frequency- and spatially
degenerate two-photon field. The method of statistical estimation of the
quantum state based on solving the likelihood equation and analyzing the
statistical properties of the obtained estimates is developed. Using the root
approach of estimating quantum states, the initial two-photon state vector is
reproduced from the measured fourth moments in the field . The developed
approach applied to quantum states reconstruction is based on the amplitudes of
mutually complementary processes. Classical algorithm of statistical estimation
based on the Fisher information matrix is generalized to the case of quantum
systems obeying Bohr's complementarity principle. It has been experimentally
proved that biphoton-qutrit states can be reconstructed with the fidelity of
0.995-0.999 and higher.Comment: Submitted to Physical Review
Bim: the setback or solution to project cost issues in Malaysia construction industry?
Malaysia is progressing into Industry Revolution (IR) 4.0 which emphasizes more
onto digital, data and artificial intelligence where everything is expected to be automated.
However, cost tends to be a major issue at the pioneer stage of embracing technology where
Building Information Modelling (BIM) for example tends to be a cost tussle for the current
construction industry. Yet, research has shown that BIM is arguably one of the technology
platforms in combating the costing issue considering that BIM enables 3D model elements to
link to cost and auto-generate quantities which potentially achieve cost-effective project. Due
to the conflicting perspectives of how BIM affects project cost issues, it is imperative to
investigate the cost-related issues in implementing BIM in the project and to determine how
BIM in general positively influences the overall project cost. Qualitative research is adopted in
this study. A semi-structured interview was conducted among four professionals who employs
BIM in their project. They consist of the assistant manager, senior manager and chief executive
officer. The data collected is analysed by utilising Matrix Table for better organisation. The
scope of the study is in the Selangor state in which the local construction industry had applied
BIM in their construction industry up to the 3D stage. The results showed that the BIM
implementation cost is not too burdensome as it is only a one-time cost and does not vary
throughout the project period. In addition, the BIM influence on the overall cost of the project
is beneficial to the industry. It improves workflow and cost management. In conclusion, BIM is
beneficial to the construction industry in the long term. It is important to resolve the costrelated issues for implement BIM and hence, encourage the usage of BIM, especially in the IR
4.0 ecosyste
Generation of a wave packet tailored to efficient free space excitation of a single atom
We demonstrate the generation of an optical dipole wave suitable for the
process of efficiently coupling single quanta of light and matter in free
space. We employ a parabolic mirror for the conversion of a transverse beam
mode to a focused dipole wave and show the required spatial and temporal
shaping of the mode incident onto the mirror. The results include a proof of
principle correction of the parabolic mirror's aberrations. For the application
of exciting an atom with a single photon pulse we demonstrate the creation of a
suitable temporal pulse envelope. We infer coupling strengths of 89% and
success probabilities of up to 87% for the application of exciting a single
atom for the current experimental parameters.Comment: to be published in Europ. Phys. J.
Entanglement-enhanced probing of a delicate material system
Quantum metrology uses entanglement and other quantum effects to improve the
sensitivity of demanding measurements. Probing of delicate systems demands high
sensitivity from limited probe energy and has motivated the field's key
benchmark-the standard quantum limit. Here we report the first
entanglement-enhanced measurement of a delicate material system. We
non-destructively probe an atomic spin ensemble by means of near-resonant
Faraday rotation, a measurement that is limited by probe-induced scattering in
quantum-memory and spin-squeezing applications. We use narrowband,
atom-resonant NOON states to beat the standard quantum limit of sensitivity by
more than five standard deviations, both on a per-photon and per-damage basis.
This demonstrates quantum enhancement with fully realistic loss and noise,
including variable-loss effects. The experiment opens the way to ultra-gentle
probing of single atoms, single molecules, quantum gases and living cells.Comment: 7 pages, 8 figures; Nature Photonics, advance online publication, 16
December 201
An SU(N) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling
The Hubbard model, containing only the minimum ingredients of nearest
neighbor hopping and on-site interaction for correlated electrons, has
succeeded in accounting for diverse phenomena observed in solid-state
materials. One of the interesting extensions is to enlarge its spin symmetry to
SU(N>2), which is closely related to systems with orbital degeneracy. Here we
report a successful formation of the SU(6) symmetric Mott insulator state with
an atomic Fermi gas of ytterbium (173Yb) in a three-dimensional optical
lattice. Besides the suppression of compressibility and the existence of charge
excitation gap which characterize a Mott insulating phase, we reveal an
important difference between the cases of SU(6) and SU(2) in the achievable
temperature as the consequence of different entropy carried by an isolated
spin. This is analogous to Pomeranchuk cooling in solid 3He and will be helpful
for investigating exotic quantum phases of SU(N) Hubbard system at extremely
low temperatures.Comment: 20 pages, 6 figures, to appear in Nature Physic
Quantum Computing and Quantum Simulation with Group-II Atoms
Recent experimental progress in controlling neutral group-II atoms for
optical clocks, and in the production of degenerate gases with group-II atoms
has given rise to novel opportunities to address challenges in quantum
computing and quantum simulation. In these systems, it is possible to encode
qubits in nuclear spin states, which are decoupled from the electronic state in
the S ground state and the long-lived P metastable state on the
clock transition. This leads to quantum computing scenarios where qubits are
stored in long lived nuclear spin states, while electronic states can be
accessed independently, for cooling of the atoms, as well as manipulation and
readout of the qubits. The high nuclear spin in some fermionic isotopes also
offers opportunities for the encoding of multiple qubits on a single atom, as
well as providing an opportunity for studying many-body physics in systems with
a high spin symmetry. Here we review recent experimental and theoretical
progress in these areas, and summarise the advantages and challenges for
quantum computing and quantum simulation with group-II atoms.Comment: 11 pages, 7 figures, review for special issue of "Quantum Information
Processing" on "Quantum Information with Neutral Particles
Understanding the Relationship Between Perceived Quality Cues and Quality Attributes in the Purchase of Meat in Malaysia
This study utilizes the Total Food Quality Model to gain a better understanding of how Malaysian consumers make their decision to purchase fresh/chilled meat. We examine the association between quality cues and desired values (quality attributes) with regard to food that is guaranteed Halal, safe to eat, healthy and nutritious, has a good taste, represents good value for money, and is produced in a way that protects the environment and worker welfare. The findings reveal that different quality cues assume different levels of importance when pursuing different desired values
Epstein Barr Virus-positive large T-cell lymphoma presenting as acute appendicitis 17 years after cadaveric renal transplant: a case report
<p>Abstract</p> <p>Introduction</p> <p>The majority of post-transplant lymphoproliferative disorders in renal transplant patients are of the B-cell phenotype, while the T-cell phenotype is rare. We report a case of Epstein Barr Virus-positive, T-cell lymphoma in a renal transplant patient, presenting unusually as acute appendicitis.</p> <p>Case presentation</p> <p>A 45-year-old Hispanic male renal transplant patient presented with right-side abdominal pain 17 years after transplant. The laboratory studies were unremarkable. Laparoscopic exploration showed an inflamed appendix so a laparoscopic appendectomy was performed. Pathology of the appendix showed large cells positive for CD3, CD56 and Epstein Barr Virus-encoded RNA staining, and negative for CD20 and CD30. The tissue tested positive for T-cell receptor gene rearrangement by polymerase chain reaction analysis. Treatment management involved reduction of immunosuppression and initiation of chemotherapy with cisplatin, etoposide, gemcitabine, and solumedrol followed by cyclophosphamide, hydroxydaunorubicin, vincristine and prednisone). He recovered and the allo-grafted kidney is fully functional.</p> <p>Conclusion</p> <p>We report a rare case of post-renal transplant large T-cell lymphoma, with an unusual presentation of acute appendicitis and Epstein Barr Virus-positivity, which responded well to chemotherapy.</p
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