1,552 research outputs found
Three-dimensional in vitro models of prostate cancer
Issued as final reportGeorgia Cancer Coalitio
Engineering Photon Delocalization in a Rabi Dimer with a Dissipative Bath
A Rabi dimer is used to model a recently reported circuit quantum
electrodynamics system composed of two coupled transmission-line resonators
with each coupled to one qubit. In this study, a phonon bath is adopted to
mimic the multimode micromechanical resonators and is coupled to the qubits in
the Rabi dimer. The dynamical behavior of the composite system is studied by
the Dirac-Frenkel time-dependent variational principle combined with the
multiple Davydov D ans\"{a}tze. Initially all the photons are pumped into
the left resonator, and the two qubits are in the down state coupled with the
phonon vacuum. In the strong qubit-photon coupling regime, the photon dynamics
can be engineered by tuning the qubit-bath coupling strength and
photon delocalization is achieved by increasing . In the absence of
dissipation, photons are localized in the initial resonator. Nevertheless, with
moderate qubit-bath coupling, photons are delocalized with quasiequilibration
of the photon population in two resonators at long times. In this case, high
frequency bath modes are activated by interacting with depolarized qubits. For
strong dissipation, photon delocalization is achieved via frequent
photon-hopping within two resonators and the qubits are suppressed in their
initial down state.Comment: 11 pages, 11 figure
Universal quantized spin-Hall conductance fluctuation in graphene
We report a theoretical investigation of quantized spin-Hall conductance
fluctuation of graphene devices in the diffusive regime. Two graphene models
that exhibit quantized spin-Hall effect (QSHE) are analyzed. Model-I is with
unitary symmetry under an external magnetic field but with zero
spin-orbit interaction, . Model-II is with symplectic symmetry where
B=0 but . Extensive numerical calculations indicate that the two
models have exactly the same universal QSHE conductance fluctuation value
regardless of the symmetry. Qualitatively different from the
conventional charge and spin universal conductance distributions, in the
presence of edge states the spin-Hall conductance shows an one-sided log-normal
distribution rather than a Gaussian distribution. Our results strongly suggest
that the quantized spin-Hall conductance fluctuation belongs to a new
universality class
To Enhance Light Extraction for Organic Light-Emitting Diodes by Body Modification of Substrate
A facile approach of body modification on substrate is introduced to enhance the light extraction for organic devices. The lateral metal reflective film (LMRF) was coated on side of substrate and microlens array (MLA) was fabricated on forward surface of substrate. The two methods of improving light output are simulated and optimized to form body modification. The metal thin film was evaporated on the side of reversal trapezoid shape substrate to form LMRF layer and the MLA with semicircle shape was fabricated on the substrate using normal photolithography process. The external quantum efficiency of fabricated organic device with body modification is ~1.8 times higher than the device with normal substrate
Super cavity solitons and the coexistence of multiple nonlinear states in a tristable passive Kerr resonator
Passive Kerr cavities driven by coherent laser fields display a rich
landscape of nonlinear physics, including bistability, pattern formation, and
localised dissipative structures (solitons). Their conceptual simplicity has
for several decades offered an unprecedented window into nonlinear cavity
dynamics, providing insights into numerous systems and applications ranging
from all-optical memory devices to microresonator frequency combs. Yet despite
the decades of study, a recent theoretical study has surprisingly alluded to an
entirely new and unexplored paradigm in the regime where nonlinearly tilted
cavity resonances overlap with one another [T. Hansson and S. Wabnitz, J. Opt.
Soc. Am. B 32, 1259 (2015)]. We have used synchronously driven fiber ring
resonators to experimentally access this regime, and observed the rise of new
nonlinear dissipative states. Specifically, we have observed, for the first
time to the best of our knowledge, the stable coexistence of dissipative
(cavity) solitons and extended modulation instability (Turing) patterns, and
performed real time measurements that unveil the dynamics of the ensuing
nonlinear structures. When operating in the regime of continuous wave
tristability, we have further observed the coexistence of two distinct cavity
soliton states, one of which can be identified as a "super" cavity soliton as
predicted by Hansson and Wabnitz. Our experimental findings are in excellent
agreement with theoretical analyses and numerical simulations of the
infinite-dimensional Ikeda map that governs the cavity dynamics. The results
from our work reveal that experimental systems can support complex combinations
of distinct nonlinear states, and they could have practical implications to
future microresonator-based frequency comb sources.Comment: 13 pages, 6 figure
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