6,157 research outputs found
Transitionless-based shortcuts for the fast and robust generation of W states
We propose a scheme to generate W states based on transitionles-based
shortcuts technique in cavity quantum electrodynamics (QED) system. In light of
quantum Zeno dynamics, we first effectively design a system whose effective
Hamiltonian is equivalent to the counter-diabatic driving Hamiltonian
constructed by transitionless quantum driving, then, realize the W states'
generation within this framework. For the sake of clearness, we describe two
stale schemes for W states' generation via traditional methods: the adiabatic
dark-state evolution and the quantum Zeno dynamics. The comparison among these
three schemes shows the shortcut scheme is closely related to the other two but
better than them. That is, numerical investigation demonstrates that the
shortcut scheme is faster than the adiabatic one, and more robust against
operational imperfection than the Zeno one. What is more, the present scheme is
also robust against decoherence caused by spontaneous emission and photon loss.Comment: 11 pages, 9 figure
Wetting and Diffusion of Water on Pristine and Strained Phosphorene
Phosphorene, a newly fabricated two-dimensional (2D) nanomaterial, have
exhibited promising application prospect in biology. Nonetheless, the wetting
and diffusive properties of bio-fluids on phosphorene are still elusive. In
this study, using molecular dynamics (MD) simulations, we investigated the
structural and dynamic properties of water on pristine and strained
phosphorene. The MD simulations illustrated that the diffusion of water
molecules on the phosphorene surface is anisotropic, while strain-enhanced
diffusion is clearly present which arises from strain-induced smooth of the
energy landscape. The contact angle of water droplet on phosphorene exhibited a
nonmonotonic variation with the transverse strain. The structure of water on
transverse stretched phosphorene was demonstrated to be different from that on
longitudinal stretched phosphorene. Moreover, we discovered that the contact
angle of water on strained phosphorene is proportional to the quotient of
longitudinal and transverse diffusion coefficients of interfacial water. These
findings would offer helpful insights in potential ways of manipulating the
wetting and transport of water at nanoscale, and in future bio-applications of
phosphorene.Comment: 8 pages, 6 figure
Shortcuts to adiabatic passage for fast generation of three-atom singlet state by transitionless quantum driving
Motivated by transitionless quantum driving, we construct shortcuts to
adiabatic passage in a three-atom system to create a singlet state with the
help of quantum zeno dynamics and non-resonant lasers. The influence of various
decoherence processes is discussed by numerical simulation and the results
reveal that the scheme is fast and robust against decoherence and operational
imperfection. We also investigate how to select the experimental parameters to
control the cavity dissipation and atomic spontaneous emission which will have
an application value in experiment.Comment: 19 pages, 9 figures, has been accepted by Scientific Reports. arXiv
admin note: text overlap with arXiv:1411.6747. text overlap with
arXiv:1411.674
Invariant-based pulse design for three-level systems without the rotating-wave approximation
In this paper, a scheme is put forward to design pulses which drive a
three-level system based on the reverse engineering with Lewis-Riesenfeld
invariant theory. The scheme can be applied to a three-level system even when
the rotating-wave approximation (RWA) can not be used. The amplitudes of pulses
and the maximal values of detunings in the system could be easily controlled by
adjusting control parameters. We analyze the dynamics of the system by an
invariant operator, so additional couplings are unnecessary. Moreover, the
approaches to avoid singularity of pulses are studied and several useful
results are obtained. We hope the scheme could contribute to fast quantum
information processing without RWA.Comment: 9 pages 9 figures, has been accepted for publication as a Regular
Article in Annalen der Physi
Arbitrary quantum state engineering in three-state systems via Counterdiabatic driving
A scheme for arbitrary quantum state engineering (QSE) in three-state systems
is proposed. Firstly, starting from a set of complete orthogonal time-dependent
basis with undetermined coefficients, a time-dependent Hamiltonian is derived
via Counterdiabatic driving for the purpose of guiding the system to attain an
arbitrary target state at a predefined time. Then, on request of the assumed
target states, two single-mode driving protocols and a multi-mode driving
protocol are proposed as examples to discuss the validity of the QSE scheme.
The result of comparison between single-mode driving and multi-mode driving
shows that multi-mode driving seems to have a wider rang of application
prospect because it can drive the system to an arbitrary target state from an
arbitrary initial state also at a predefined time even without the use of
microwave fields for the transition between the two ground states. Moreover,
for the purpose of discussion in the scheme's feasibility in practice, a
polynomial ansatz as the simplest exampleis used to fix the pulses. The result
shows that the pulses designed to implement the protocols are not hard to be
realized in practice. At the end, QSE in higher-dimensional systems is also
discussed in brief as a generalization example of the scheme.Comment: 16 pages, 13 figures, has been accepted by Scientific Report
Method for constructing shortcuts to adiabaticity by a substitute of counterdiabatic driving terms
We propose an efficientmethod to construct shortcuts to adiabaticity through
designing a substitute Hamiltonian to try to avoid the defect in which the
speed-up protocol' Hamiltonian may involve terms which are difficult to realize
in practice. We show that as long as the counterdiabatic coupling terms-even
only some of them-have been nullified by the additional Hamiltonian, the
corresponding shortcuts to the adiabatic process could be constructed and the
adiabatic process would be sped up. As an application example, we apply this
method to the popular Landau-Zener model for the realization of fast population
inversion. The results show that in both Hermitian and non-Hermitian systems,
we can design different additional Hamiltonians to replace the traditional
counterdiabatic driving Hamiltonian to speed up the process. This method
provides many choices for designing additional terms of the Hamiltonian such
that one can choose a realizable model in practice.Comment: 11pages, 6 figures, has been accepted for publication as a Regular
Article in Physicial Review
A Multimodal Late Fusion Model for E-Commerce Product Classification
The cataloging of product listings is a fundamental problem for most
e-commerce platforms. Despite promising results obtained by unimodal-based
methods, it can be expected that their performance can be further boosted by
the consideration of multimodal product information. In this study, we
investigated a multimodal late fusion approach based on text and image
modalities to categorize e-commerce products on Rakuten. Specifically, we
developed modal specific state-of-the-art deep neural networks for each input
modal, and then fused them at the decision level. Experimental results on
Multimodal Product Classification Task of SIGIR 2020 E-Commerce Workshop Data
Challenge demonstrate the superiority and effectiveness of our proposed method
compared with unimodal and other multimodal methods. Our team named pa_curis
won the 1st place with a macro-F1 of 0.9144 on the final leaderboard.Comment: 4 pages, SIGIR 2020 E-commerce Workshop Data Challenge Technical
Repor
A Hybrid BERT and LightGBM based Model for Predicting Emotion GIF Categories on Twitter
The animated Graphical Interchange Format (GIF) images have been widely used
on social media as an intuitive way of expression emotion. Given their
expressiveness, GIFs offer a more nuanced and precise way to convey emotions.
In this paper, we present our solution for the EmotionGIF 2020 challenge, the
shared task of SocialNLP 2020. To recommend GIF categories for unlabeled
tweets, we regarded this problem as a kind of matching tasks and proposed a
learning to rank framework based on Bidirectional Encoder Representations from
Transformer (BERT) and LightGBM. Our team won the 4th place with a Mean Average
Precision @ 6 (MAP@6) score of 0.5394 on the round 1 leaderboard.Comment: 4 pages, ACL 2020 EmotionGIF Challenge Technical Repor
Improving the stimulated Raman adiabatic passage via dissipative quantum dynamics
We propose a method to improve the stimulated Raman adiabatic passage
(STIRAP) via dissipative quantum dynamics, taking into account the dephasing
effects. Fast and robust population transfer can be obtained with the scheme by
the designed pulses and detuning, even though the initial state of the system
is imperfect. With a concrete three-level system as an example, the influences
of the imperfect initial state, variations in the control parameters, and
various dissipation effects are discussed in detail. The numerical simulation
shows that the scheme is insensitive to moderate fluctuations of experimental
parameters and the relatively large dissipation effects of the excited state.
Furthermore, the dominant dissipative factors, namely, the dephasing effects of
the ground states and the imperfect initial state are no longer undesirable, in
fact, they are the important resources to the scheme. Therefore, the scheme
could provide more choices for the realization of the complete population
transfer in the strong dissipative fieldsComment: 8 pages, 10 figures, has been accepted by Optics Expres
Fast quantum state engineering via universal SU(2) transformation
We introduce a simple yet versatile protocol to inverse engineer the
time-dependent Hamiltonian in two- and three level systems. In the protocol, by
utilizing a universal SU(2) transformation, a given speedup goal can be
obtained with large freedom to select the control parameters. As an
illustration example, the protocol is applied to perform population transfer
between nitrogen-vacancy (NV) centers in diamond. Numerical simulation shows
that the speed of the present protocol is fast compared with that of the
adiabatic process. Moreover, the protocol is also tolerant to decoherence and
experimental parameter fluctuations. Therefore, the protocol may be useful for
designing an experimental feasible Hamiltonian to engineer a quantum system.Comment: 11 pages, 8 figures, has been accepted by Physical Review
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