255 research outputs found
Unitary equivalence between ordinary intelligent states and generalized intelligent states
Ordinary intelligent states (OIS) hold equality in the Heisenberg uncertainty
relation involving two noncommuting observables {A, B}, whereas generalized
intelligent states (GIS) do so in the more generalized uncertainty relation,
the Schrodinger-Robertson inequality. In general, OISs form a subset of GISs.
However, if there exists a unitary evolution U that transforms the operators
{A, B} to a new pair of operators in a rotation form, it is shown that an
arbitrary GIS can be generated by applying the rotation operator U to a certain
OIS. In this sense, the set of OISs is unitarily equivalent to the set of GISs.
It is the case, for example, with the su(2) and the su(1,1) algebra that have
been extensively studied particularly in quantum optics. When these algebras
are represented by two bosonic operators (nondegenerate case), or by a single
bosonic operator (degenerate case), the rotation, or pseudo-rotation, operator
U corresponds to phase shift, beam splitting, or parametric amplification,
depending on two observables {A, B}.Comment: published version, 4 page
Unitary equivalence between ordinary intelligent states and generalized intelligent states
Ordinary intelligent states (OIS) hold equality in the Heisenberg uncertainty
relation involving two noncommuting observables {A, B}, whereas generalized
intelligent states (GIS) do so in the more generalized uncertainty relation,
the Schrodinger-Robertson inequality. In general, OISs form a subset of GISs.
However, if there exists a unitary evolution U that transforms the operators
{A, B} to a new pair of operators in a rotation form, it is shown that an
arbitrary GIS can be generated by applying the rotation operator U to a certain
OIS. In this sense, the set of OISs is unitarily equivalent to the set of GISs.
It is the case, for example, with the su(2) and the su(1,1) algebra that have
been extensively studied particularly in quantum optics. When these algebras
are represented by two bosonic operators (nondegenerate case), or by a single
bosonic operator (degenerate case), the rotation, or pseudo-rotation, operator
U corresponds to phase shift, beam splitting, or parametric amplification,
depending on two observables {A, B}.Comment: published version, 4 page
Generating a Schr\"odinger-cat-like state via a coherent superposition of photonic operations
We propose an optical scheme to generate a superposition of coherent states
with enhanced size adopting an interferometric setting at the single-photon
level currently available in the laboratory. Our scheme employs a nondegenerate
optical parametric amplifier together with two beam splitters so that the
detection of single photons at the output conditionally implements the desired
superposition of second-order photonic operations. We analyze our proposed
scheme by considering realistic on-off photodetectors with nonideal efficiency
in heralding the success of conditional events. A high-quality performance of
our scheme is demonstrated in view of various criteria such as quantum
fidelity, mean output energy, and measure of quantum interference
Entanglement criteria via the uncertainty relations in su(2) and su(1,1) algebra: detection of non-Gaussian entangled states
We derive a class of inequalities, from the uncertainty relations of the
SU(1,1) and the SU(2) algebra in conjunction with partial transposition, that
must be satisfied by any separable two-mode states. These inequalities are
presented in terms of the su(2) operators J_x, J_y, and the total photon number
N_a+N_b. They include as special cases the inequality derived by Hillery and
Zubairy [Phys. Rev. Lett. 96, 050503 (2006)], and the one by Agarwal and Biswas
[New J. Phys. 7, 211 (2005)]. In particular, optimization over the whole
inequalities leads to the criterion obtained by Agarwal and Biswas. We show
that this optimal criterion can detect entanglement for a broad class of
non-Gaussian entangled states, i.e., the su(2) minimum-uncertainty states.
Experimental schemes to test the optimal criterion are also discussed,
especially the one using linear optical devices and photodetectors.Comment: published version, presentation polished with references added, 7
pages, 4 figure
Entanglement detection via tighter local uncertainty relations
We propose an entanglement criterion based on local uncertainty relations
(LURs) in a stronger form than the original LUR criterion introduced in [H. F.
Hofmann and S. Takeuchi, Phys. Rev. A \textbf{68}, 032103 (2003)]. Using
arbitrarily chosen operators and of
subsystems A and B, the tighter LUR criterion, which may be used not only for
discrete variables but also for continuous variables, can detect more entangled
states than the original criterion.Comment: 6 pages, 2 figure
Needle Tract Implantation after Percutaneous Interventional Procedures in Hepatocellular Carcinomas: Lessons Learned from a 10-year Experience
Percutaneous interventional procedures under image guidance, such as biopsy, ethanol injection therapy, and radiofrequency ablation play important roles in the management of hepatocellular carcinomas. Although uncommon, the procedures may result in tumor implantation along the needle tract, which is a major delayed complication. Implanted tumors usually appear as one or a few, round or oval-shaped, enhancing nodules along the needle tract on CT, from the intraperitoneum through the intercostal or abdominal muscles to the subcutaneous or cutaneous tissues. Radiologists should understand the mechanisms and risk factors of needle tract implantation, minimize this complication, and also pay attention to the presence of implanted tumors along the needle tract during follow-up
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