961 research outputs found
Demonstration of Adiabatic Variational Quantum Computing with a Superconducting Quantum Coprocessor
Adiabatic quantum computing enables the preparation of many-body ground
states. This is key for applications in chemistry, materials science, and
beyond. Realisation poses major experimental challenges: Direct analog
implementation requires complex Hamiltonian engineering, while the digitised
version needs deep quantum gate circuits. To bypass these obstacles, we suggest
an adiabatic variational hybrid algorithm, which employs short quantum circuits
and provides a systematic quantum adiabatic optimisation of the circuit
parameters. The quantum adiabatic theorem promises not only the ground state
but also that the excited eigenstates can be found. We report the first
experimental demonstration that many-body eigenstates can be efficiently
prepared by an adiabatic variational algorithm assisted with a multi-qubit
superconducting coprocessor. We track the real-time evolution of the ground and
exited states of transverse-field Ising spins with a fidelity up that can reach
about 99%.Comment: 12 pages, 4 figure
The Impact of Social Movement on Racial Diversification Initiatives: Evidence From the Movie Industry
The movie industry is facing rising advocacy for racially inclusive casting. However, it remains an open question whether the promised benefits of racial diversification will materialize. Using data from 540 movies nested in 258 sequels released from 2008 to 2021, we find that, on average, increasing the number of racial minority actors in the main cast depresses movie evaluations. More importantly, the negative effect of racial diversification attenuates after Black Lives Matter (#BLM), a new media enabled social movement. Further, incorporating insights from tokenism and discrimination theories, we probe the heterogeneity in the bias mitigation effects of #BLM and find movie type and the core production team’s credentials as important boundary conditions. The present research shows that a social movement that seeks to address racial inequality can, indeed, lead to meaningful changes in public opinions toward racial inclusive initiatives. It also provides perspectives for thinking about the mechanisms underlying such changes
The Impact of Social Movement on Racial Diversification Initiatives: Evidence From the Movie Industry
The movie industry is facing rising advocacy for racially inclusive casting. However, it remains an open question whether the promised benefits of racial diversification will materialize. Using data from 540 movies nested in 258 sequels released from 2008 to 2021, we find that, on average, increasing the number of racial minority actors in the main cast depresses movie evaluations. More importantly, the negative effect of racial diversification attenuates after Black Lives Matter (#BLM), a new media enabled social movement. Further, incorporating insights from tokenism and discrimination theories, we probe the heterogeneity in the bias mitigation effects of #BLM and find movie type and the core production team’s credentials as important boundary conditions. The present research shows that a social movement that seeks to address racial inequality can, indeed, lead to meaningful changes in public opinions toward racial inclusive initiatives. It also provides perspectives for thinking about the mechanisms underlying such changes
Fast multi-channel inverse design through augmented partial factorization
Computer-automated design and discovery have led to high-performance
nanophotonic devices with diverse functionalities. However, massively
multi-channel systems such as metasurfaces controlling many incident angles and
photonic-circuit components coupling many waveguide modes still present a
challenge. Conventional methods require forward simulations and
adjoint simulations -- simulations in total -- to
compute the objective function and its gradient for a design involving the
response to input channels. By generalizing the adjoint method and
the recently proposed augmented partial factorization method, here we show how
to obtain both the objective function and its gradient for a massively
multi-channel system in a single simulation, achieving
over-two-orders-of-magnitude speedup and reduced memory usage. We use this
method to inverse design a metasurface beam splitter that separates the
incident light to the target diffraction orders for all incident angles of
interest, a key component of the dot projector for 3D sensing. This formalism
enables efficient inverse design for a wide range of multi-channel optical
systems
High-efficiency high-NA metalens designed by maximizing the efficiency limit
Theoretical bounds are commonly used to assess the limitations of photonic
design. Here we introduce a more active way to use theoretical bounds,
integrating them into part of the design process and identifying optimal system
parameters that maximize the efficiency limit itself. As an example, we
consider wide-field-of-view high-numerical-aperture metalenses, which can be
used for high-resolution imaging in microscopy and endoscopy, but no existing
design has achieved a high efficiency. By choosing aperture sizes to maximize
an efficiency bound, setting the thickness according to a thickness bound, and
then performing inverse design, we come up with high-numerical-aperture (NA =
0.9) metalens designs with record-high 98% transmission efficiency and 92%
Strehl ratio across all incident angles within a 60-deg field of view, reaching
the maximized bound. This maximizing-efficiency-limit approach applies to any
multi-channel system and can help a wide range of optical devices reach their
highest possible performance
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