15,679 research outputs found
Demonstration of Geometric Landau-Zener Interferometry in a Superconducting Qubit
Geometric quantum manipulation and Landau-Zener interferometry have been
separately explored in many quantum systems. In this Letter, we combine these
two approaches to study the dynamics of a superconducting phase qubit. We
experimentally demonstrate Landau-Zener interferometry based on the pure
geometric phases in this solid-state qubit. We observe the interference caused
by a pure geometric phase accumulated in the evolution between two consecutive
Landau-Zener transitions, while the dynamical phase is canceled out by a
spin-echo pulse. The full controllability of the qubit state as a function of
the intrinsically robust geometric phase provides a promising approach for
quantum state manipulation.Comment: 5 pages + 3 pages supplemental Materia
A Survey of Embodied AI: From Simulators to Research Tasks
There has been an emerging paradigm shift from the era of "internet AI" to
"embodied AI", where AI algorithms and agents no longer learn from datasets of
images, videos or text curated primarily from the internet. Instead, they learn
through interactions with their environments from an egocentric perception
similar to humans. Consequently, there has been substantial growth in the
demand for embodied AI simulators to support various embodied AI research
tasks. This growing interest in embodied AI is beneficial to the greater
pursuit of Artificial General Intelligence (AGI), but there has not been a
contemporary and comprehensive survey of this field. This paper aims to provide
an encyclopedic survey for the field of embodied AI, from its simulators to its
research. By evaluating nine current embodied AI simulators with our proposed
seven features, this paper aims to understand the simulators in their provision
for use in embodied AI research and their limitations. Lastly, this paper
surveys the three main research tasks in embodied AI -- visual exploration,
visual navigation and embodied question answering (QA), covering the
state-of-the-art approaches, evaluation metrics and datasets. Finally, with the
new insights revealed through surveying the field, the paper will provide
suggestions for simulator-for-task selections and recommendations for the
future directions of the field.Comment: Under Review for IEEE TETC
Evolution of Fermion Resonance in Thick Brane
In this work, we investigate numerical evolution of massive Kaluza-Klein (KK)
modes of a Dirac field on a thick brane. We deduce the Dirac equation in
five-dimensional spacetime, and obtain the time-dependent evolution equation
and Schr\"odinger-like equation of the extra-dimensional component. We use the
Dirac KK resonances as the initial data and study the corresponding dynamics.
By monitoring the decay law of the left- and right-chiral KK resonances, we
compute the corresponding lifetimes and find that there could exist long-lived
KK modes on the brane. Especially, for the lightest KK resonance with a large
coupling parameter and a large three momentum, it will have an extremely long
lifetime.Comment: 26 pages, 12 figure
Simulating the Kibble-Zurek mechanism of the Ising model with a superconducting qubit system
The Kibble-Zurek mechanism (KZM) predicts the density of topological defects
produced in the dynamical processes of phase transitions in systems ranging
from cosmology to condensed matter and quantum materials. The similarity
between KZM and the Landau-Zener transition (LZT), which is a standard tool to
describe the dynamics of some non-equilibrium physics in contemporary physics,
is being extensively exploited. Here we demonstrate the equivalence between KZM
in the Ising model and LZT in a superconducting qubit system. We develop a
time-resolved approach to study quantum dynamics of LZT with nano-second
resolution. By using this technique, we simulate the key features of KZM in the
Ising model with LZT, e.g., the boundary between the adiabatic and impulse
regions, the freeze-out phenomenon in the impulse region, especially, the
scaling law of the excited state population as the square root of the quenching
rate. Our results supply the experimental evidence of the close connection
between KZM and LZT, two textbook paradigms to study the dynamics of the
non-equilibrium phenomena.Comment: Title changed, authors added, and some experimental data update
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