18,721 research outputs found
Single-shot fault-tolerant quantum error correction
Conventional quantum error correcting codes require multiple rounds of
measurements to detect errors with enough confidence in fault-tolerant
scenarios. Here I show that for suitable topological codes a single round of
local measurements is enough. This feature is generic and is related to
self-correction and confinement phenomena in the corresponding quantum
Hamiltonian model. 3D gauge color codes exhibit this single-shot feature, which
applies also to initialization and gauge-fixing. Assuming the time for
efficient classical computations negligible, this yields a topological
fault-tolerant quantum computing scheme where all elementary logical operations
can be performed in constant time.Comment: Typos corrected after publication in journal, 26 pages, 4 figure
EEG-Based Emotion Recognition Using Regularized Graph Neural Networks
Electroencephalography (EEG) measures the neuronal activities in different
brain regions via electrodes. Many existing studies on EEG-based emotion
recognition do not fully exploit the topology of EEG channels. In this paper,
we propose a regularized graph neural network (RGNN) for EEG-based emotion
recognition. RGNN considers the biological topology among different brain
regions to capture both local and global relations among different EEG
channels. Specifically, we model the inter-channel relations in EEG signals via
an adjacency matrix in a graph neural network where the connection and
sparseness of the adjacency matrix are inspired by neuroscience theories of
human brain organization. In addition, we propose two regularizers, namely
node-wise domain adversarial training (NodeDAT) and emotion-aware distribution
learning (EmotionDL), to better handle cross-subject EEG variations and noisy
labels, respectively. Extensive experiments on two public datasets, SEED and
SEED-IV, demonstrate the superior performance of our model than
state-of-the-art models in most experimental settings. Moreover, ablation
studies show that the proposed adjacency matrix and two regularizers contribute
consistent and significant gain to the performance of our RGNN model. Finally,
investigations on the neuronal activities reveal important brain regions and
inter-channel relations for EEG-based emotion recognition
Topological Quantum Computing
This set of lecture notes forms the basis of a series of lectures delivered
at the 48th IFF Spring School 2017 on Topological Matter: Topological
Insulators, Skyrmions and Majoranas at Forschungszentrum Juelich, Germany. The
first part of the lecture notes covers the basics of abelian and non-abelian
anyons and their realization in the Kitaev's honeycomb model. The second part
discusses how to perform universal quantum computation using Majorana fermions.Comment: In Topological Matter: Topological Insulators, Skyrmions and
Majoranas, Lecture notes of the 48th IFF Spring School 2017, eds. S. Bluegel,
Y. Mokrusov, T. Schaepers, and Y. Ando (Forschungszentrum Juelich, Key
Technologies, Vol. 139, 2017), Sec. D
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