40,130 research outputs found
A General SU(2) Formulation for Quantum Searching with Certainty
A general quantum search algorithm with arbitrary unitary transformations and
an arbitrary initial state is considered in this work. To serach a marked state
with certainty, we have derived, using an SU(2) representation: (1) the
matching condition relating the phase rotations in the algorithm, (2) a concise
formula for evaluating the required number of iterations for the search, and
(3) the final state after the search, with a phase angle in its amplitude of
unity modulus. Moreover, the optimal choices and modifications of the phase
angles in the Grover kernel is also studied.Comment: 8 pages, 2 figure
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Rapid Manufactured Textiles
Rapid Manufacturing (RM) is increasingly becoming a viable manufacturing process due
to dramatic advantages that are achievable in the area of design complexity. Through the
exploration of the design freedom, this paper introduces the concept of manufacturing textiles for
potential smart and high performance textile applications. This paper discusses the current
limitations associated with the manufacture of textiles through RM and presents a novel
methodology for the generation of 3D conformal RM textile articles. The paper concludes that
through RM it is entirely possible to manufacture a structure that incorporates drape and free
movement properties directly comparable to conventional textiles.Mechanical Engineerin
A single-photon sampling architecture for solid-state imaging
Advances in solid-state technology have enabled the development of silicon
photomultiplier sensor arrays capable of sensing individual photons. Combined
with high-frequency time-to-digital converters (TDCs), this technology opens up
the prospect of sensors capable of recording with high accuracy both the time
and location of each detected photon. Such a capability could lead to
significant improvements in imaging accuracy, especially for applications
operating with low photon fluxes such as LiDAR and positron emission
tomography.
The demands placed on on-chip readout circuitry imposes stringent trade-offs
between fill factor and spatio-temporal resolution, causing many contemporary
designs to severely underutilize the technology's full potential. Concentrating
on the low photon flux setting, this paper leverages results from group testing
and proposes an architecture for a highly efficient readout of pixels using
only a small number of TDCs, thereby also reducing both cost and power
consumption. The design relies on a multiplexing technique based on binary
interconnection matrices. We provide optimized instances of these matrices for
various sensor parameters and give explicit upper and lower bounds on the
number of TDCs required to uniquely decode a given maximum number of
simultaneous photon arrivals.
To illustrate the strength of the proposed architecture, we note a typical
digitization result of a 120x120 photodiode sensor on a 30um x 30um pitch with
a 40ps time resolution and an estimated fill factor of approximately 70%, using
only 161 TDCs. The design guarantees registration and unique recovery of up to
4 simultaneous photon arrivals using a fast decoding algorithm. In a series of
realistic simulations of scintillation events in clinical positron emission
tomography the design was able to recover the spatio-temporal location of 98.6%
of all photons that caused pixel firings.Comment: 24 pages, 3 figures, 5 table
Is U3Ni3Sn4 best described as near a quantum critical point?
Although most known non-Fermi liquid (NFL) materials are structurally or
chemically disordered, the role of this disorder remains unclear. In
particular, very few systems have been discovered that may be stoichiometric
and well ordered. To test whether U3Ni3Sn4 belongs in this latter class, we
present measurements of the x-ray absorption fine structure (XAFS) of
polycrystalline and single-crystal U3Ni3Sn4 samples that are consistent with no
measurable local structural disorder. We also present temperature-dependent
specific heat data in applied magnetic fields as high as 8 T that show features
that are inconsistent with the antiferromagnetic Griffiths' phase model, but do
support the conclusion that a Fermi liquid/NFL crossover temperature increases
with applied field. These results are inconsistent with theoretical
explanations that require strong disorder effects, but do support the view that
U3Ni3Sn4 is a stoichiometric, ordered material that exhibits NFL behavior, and
is best described as being near an antiferromagnetic quantum critical point.Comment: 9 pages, 8 figures, in press with PR
New Experimental Limit on the Electric Dipole Moment of the Electron in a Paramagnetic Insulator
We report results of an experimental search for the intrinsic Electric Dipole
Moment (EDM) of the electron using a solid-state technique. The experiment
employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a
large magnetic response at low temperatures. The presence of the eEDM would
lead to a small but non-zero magnetization as the GGG sample is subject to a
strong electric field. We search for the resulting Stark-induced magnetization
with a sensitive magnetometer. Recent progress on the suppression of several
sources of background allows the experiment to run free of spurious signals at
the level of the statistical uncertainties. We report our first limit on the
eEDM of 10ecm with 5 days of
data averaging.Comment: 9 pages, 9 figures, Revtex 4.
Self-interacting dark matter and Higgs bosons in the SU(3)_C x SU(3)_L x U(1)_N model with right-handed neutrinos
We investigate the possibility that dark matter could be made from CP-even
and CP- odd Higgs bosons in the SU(3)_C X SU(3)_L X U(1)_N (3-3-1) model with
right-handed neutrinos. This self-interacting dark matters are stable without
imposing of new symmetry and should be weak-interacting.Comment: 7 pages, Latex, To appear in Europhys. Let
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