3,937 research outputs found
Quantum walks on two kinds of two-dimensional models
In this paper, we numerically study quantum walks on two kinds of
two-dimensional graphs: cylindrical strip and Mobius strip. The two kinds of
graphs are typical two-dimensional topological graph. We study the crossing
property of quantum walks on these two models. Also, we study its dependence on
the initial state, size of the model. At the same time, we compare the quantum
walk and classical walk on these two models to discuss the difference of
quantum walk and classical walk
Dynamical generation of dark solitons in spin-orbit-coupled Bose-Einstein condensates
We numerically investigate the ground state, the Raman-driving dynamics and
the nonlinear excitations of a realized spin-orbit-coupled Bose-Einstein
condensate in a one-dimensional harmonic trap. Depending on the Raman coupling
and the interatomic interactions, three ground-state phases are identified:
stripe, plane wave and zero-momentum phases. A narrow parameter regime with
coexistence of stripe and zero-momentum or plane wave phases in real space is
found. Several sweep progresses across different phases by driving the Raman
coupling linearly in time is simulated and the non-equilibrium dynamics of the
system in these sweeps are studied. We find kinds of nonlinear excitations,
with the particular dark solitons excited in the sweep from the stripe phase to
the plane wave or zero-momentum phase within the trap. Moreover, the number and
the stability of the dark solitons can be controlled in the driving, which
provide a direct and easy way to generate dark solitons and study their
dynamics and interaction properties.Comment: 10 pages, 9 figur
Dynamic Multi-Arm Bandit Game Based Multi-Agents Spectrum Sharing Strategy Design
For a wireless avionics communication system, a Multi-arm bandit game is
mathematically formulated, which includes channel states, strategies, and
rewards. The simple case includes only two agents sharing the spectrum which is
fully studied in terms of maximizing the cumulative reward over a finite time
horizon. An Upper Confidence Bound (UCB) algorithm is used to achieve the
optimal solutions for the stochastic Multi-Arm Bandit (MAB) problem. Also, the
MAB problem can also be solved from the Markov game framework perspective.
Meanwhile, Thompson Sampling (TS) is also used as benchmark to evaluate the
proposed approach performance. Numerical results are also provided regarding
minimizing the expectation of the regret and choosing the best parameter for
the upper confidence bound
Domain and Modality Gaps for LiDAR-based Person Detection on Mobile Robots
Person detection is a crucial task for mobile robots navigating in
human-populated environments and LiDAR sensors are promising for this task,
given their accurate depth measurements and large field of view. This paper
studies existing LiDAR-based person detectors with a particular focus on mobile
robot scenarios (e.g. service robot or social robot), where persons are
observed more frequently and in much closer ranges, compared to the driving
scenarios. We conduct a series of experiments, using the recently released
JackRabbot dataset and the state-of-the-art detectors based on 3D or 2D LiDAR
sensors (CenterPoint and DR-SPAAM respectively). These experiments revolve
around the domain gap between driving and mobile robot scenarios, as well as
the modality gap between 3D and 2D LiDAR sensors. For the domain gap, we aim to
understand if detectors pretrained on driving datasets can achieve good
performance on the mobile robot scenarios, for which there are currently no
trained models readily available. For the modality gap, we compare detectors
that use 3D or 2D LiDAR, from various aspects, including performance, runtime,
localization accuracy, robustness to range and crowdedness. The results from
our experiments provide practical insights into LiDAR-based person detection
and facilitate informed decisions for relevant mobile robot designs and
applications
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