12,803 research outputs found
Symmetries and Lie algebra of the differential-difference Kadomstev-Petviashvili hierarchy
By introducing suitable non-isospectral flows we construct two sets of
symmetries for the isospectral differential-difference Kadomstev-Petviashvili
hierarchy. The symmetries form an infinite dimensional Lie algebra.Comment: 9 page
New symmetries for the Ablowitz-Ladik hierarchies
In the letter we give new symmetries for the isospectral and non-isospectral
Ablowitz-Ladik hierarchies by means of the zero curvature representations of
evolution equations related to the Ablowitz-Ladik spectral problem. Lie
algebras constructed by symmetries are further obtained. We also discuss the
relations between the recursion operator and isospectral and non-isospectral
flows. Our method can be generalized to other systems to construct symmetries
for non-isospectral equations.Comment: 11 page
Low-dose chemotherapy of hepatocellular carcinoma through triggered-release from bilayer-decorated magnetoliposomes
Low-dose (LD) chemotherapy is a promising treatment strategy that may be improved by controlled delivery. Polyethylene glycol-stabilized bilayer-decorated magnetoliposomes (dMLs) have been designed as a stimuli-responsive LD chemotherapy drug delivery system and tested in vitro using Huh-7 hepatocellular carcinoma cell line. The dMLs contained hydrophobic superparamagnetic iron oxide nanoparticles within the lipid bilayer and doxorubicin hydrochloride (DOX, 2 μM) within the aqueous core. Structural analysis by cryogenic transmission electron microscopy and dynamic light scattering showed that the assemblies were approximately 120 nm in diameter. Furthermore, the samples consisted of a mixture of dMLs and bare liposomes (no nanoparticles), which provided dual burst and spontaneous DOX release profiles, respectively. Cell viability results show that the cytotoxicity of DOX-loaded dMLs was similar to that of bare dMLs (∼10%), which indicates that spontaneous DOX leakage had little cytotoxic effect. However, when subjected to a physiologically acceptable radiofrequency (RF) electromagnetic field, cell viability was reduced up to 40% after 8 h and significant cell death (\u3e90%) was observed after 24 h. The therapeutic mechanism was intracellular RF-triggered DOX release from the dMLs and not intracellular hyperthermia due to nanoparticle heating via magnetic losses.
[Refer to PDF for graphical abstract
Extreme subradiance from two-band Bloch oscillations in atomic arrays
Atomic arrays provide an important quantum optical platform with
photon-mediated dipoledipole interactions, which can be engineered to realize
key applications in quantum information processing. A major obstacle for such
application is the fast decay of the excited states. By controlling two-band
Bloch oscillations in an atomic array under external magnetic field, here we
show that exotic subradiance can be realized and maintained at a time scale
upto 12 orders of magnitude larger than the spontaneous decay time in atomic
arrays with the finite size. The key finding is to show a way for preventing
the wavepacket of excited states scattering into the dissipative zone inside
the free space light cone, which therefore leads to the excitation staying at a
subradiant state for extremely long decay time. We show that such operation can
be achieved by introducing a spatially linear potential from external magnetic
field in atomic arrays and then manipulating interconnected two-band Bloch
oscillations along opposite directions. Our results also point out the
possibility of controllable switching between superradiant and subradiant
states, which leads to potential applications in quantum storage.Comment: 6 pages, 3 figure
Entanglement Structure: Entanglement Partitioning in Multipartite Systems and Its Experimental Detection Using Optimizable Witnesses
Creating large-scale entanglement lies at the heart of many quantum
information processing protocols and the investigation of fundamental physics.
For multipartite quantum systems, it is crucial to identify not only the
presence of entanglement but also its detailed structure. This is because in a
generic experimental situation with sufficiently many subsystems involved, the
production of so-called genuine multipartite entanglement remains a formidable
challenge. Consequently, focusing exclusively on the identification of this
strongest type of entanglement may result in an all or nothing situation where
some inherently quantum aspects of the resource are overlooked. On the
contrary, even if the system is not genuinely multipartite entangled, there may
still be many-body entanglement present in the system. An identification of the
entanglement structure may thus provide us with a hint about where
imperfections in the setup may occur, as well as where we can identify groups
of subsystems that can still exhibit strong quantum-information-processing
capabilities. However, there is no known efficient methods to identify the
underlying entanglement structure. Here, we propose two complementary families
of witnesses for the identification of such structures. They are based on the
detection of entanglement intactness and entanglement depth, each requires only
the implementation of solely two local measurements. Our method is also robust
against noises and other imperfections, as reflected by our experimental
implementation of these tools to verify the entanglement structure of five
different eight-photon entangled states. We demonstrate how their entanglement
structure can be precisely and systematically inferred from the experimental
data. In achieving this goal, we also illustrate how the same set of data can
be classically postprocessed to learn the most about the measured system.Comment: 21 pages, 13 figure
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