4,238 research outputs found
State Carving in a Chirally-Coupled Atom-Nanophotonic Cavity
Coherent quantum control of multiqubit systems represents one of the
challenging tasks in quantum science and quantum technology. Here we
theoretically investigate the reflectivity spectrum in an atom-nanophotonic
cavity with collective nonreciprocal couplings. In the strong-coupling regime
with a high cooperativity, we theoretically predict distinct on-resonance
spectral dips owing to destructive interferences of chiral couplings. Due to
the well-separated multiple dips in the spectrum, a contrasted reflectivity
suggests a new control knob over the desired entangled state preparation. We
propose to utilize such atom-nanophotonic cavity to quantum engineer the atomic
internal states via photon-mediated dipole-dipole interactions and the
chirality of decay channels, where the atomic Bell state and W states for
arbitrary number of atoms can be tailored and heralded by state carving in the
single-photon reflection spectrum. Our results pave the way toward quantum
engineering of multiqubit states and offer new opportunities for coherent and
scalable multipartite entanglement transport in atoms coupled to nanophotonic
devices.Comment: 5 figure
Generating scalable graph states in an atom-nanophotonic interface
Scalable graph states are essential for measurement-based quantum computation
and many entanglement-assisted applications in quantum technologies. Generation
of these multipartite entangled states requires a controllable and efficient
quantum device with delicate design of generation protocol. Here we propose to
prepare high-fidelity and scalable graph states in one and two dimensions,
which can be tailored in an atom-nanophotonic cavity via state carving
technique. We propose a systematic protocol to carve out unwanted state
components, which facilitates scalable graph states generations via adiabatic
transport of a definite number of atoms in optical tweezers. An analysis of
state fidelity is also presented, and the state preparation probability can be
optimized via multiqubit state carvings and sequential single-photon probes.
Our results showcase the capability of an atom-nanophotonic interface for
creating graph states and pave the way toward novel problem-specific
applications using scalable high-dimensional graph states with stationary
qubits.Comment: 5 figures with supplemental materia
Rational Approximate Symmetries of KdV Equation
We construct one-parameter deformation of the Dorfman Hamiltonian operator
for the Riemann hierarchy using the quasi-Miura transformation from topological
field theory. In this way, one can get the approximately rational symmetries of
KdV equation and then investigate its bi-Hamiltonian structure.Comment: 14 pages, no figure
Gravity Waves from Quantum Stress Tensor Fluctuations in Inflation
We consider the effects of the quantum stress tensor fluctuations of a
conformal field in generating gravity waves in inflationary models. We find a
non-scale invariant, non-Gaussian contribution which depends upon the total
expansion factor between an initial time and the end of inflation. This
spectrum of gravity wave perturbations is an illustration of a negative power
spectrum, which is possible in quantum field theory. We discuss possible
choices for the initial conditions. If the initial time is taken to be
sufficiently early, the fluctuating gravity waves are potentially observable
both in the CMB radiation and in gravity wave detectors, and could offer a
probe of transplanckian physics. The fact that they have not yet been observed
might be used to constrain the duration and energy scale of inflation.Comment: 17 -pages, no figure
PHOTOCHEMICAL RING-OPENING IN meso-CHLORINATED CHLOROPHYLLS
Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed
A BGG-type resolution for tensor modules over general linear superalgebra
We construct a Bernstein-Gelfand-Gelfand type resolution in terms of direct
sums of Kac modules for the finite-dimensional irreducible tensor
representations of the general linear superalgebra. As a consequence it follows
that the unique maximal submodule of a corresponding reducible Kac module is
generated by its proper singular vector.Comment: 11pages, LaTeX forma
Partial encapsulation of Pd particles by reduced ceria-zirconia
Direct observation of metal-oxide interfaces with atomic resolution can be achieved by cross-sectional high-resolution transmission electron microscopy (HRTEM). Using this approach to study the response of a model, single-crystal thin film automotive exhaust-gas catalyst, Pd particles supported on the (111) ceria-zirconia (CZO) surface, to a redox cycle, we have found two distinct processes for the partial encapsulation of the Pd particles by the reduced CZO surface that depend on their relative crystallographic orientations. In the case of the preferred orientation found for Pd particles on CZO, Pd(111)[110]//CZO(111)[110]Pd(111)[110]∕∕CZO(111)[110], a flat and sharp metal/oxide interface was maintained upon reduction, while ceria-zirconia from the adjacent surface tended to accumulate on and around the Pd particle. In rare cases, Pd particles with other orientations tended to sink into the oxide support upon reduction. Possible mechanisms for these encapsulation processes are proposed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87836/2/201915_1.pd
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