9,059 research outputs found
Open-Retrieval Conversational Question Answering
Conversational search is one of the ultimate goals of information retrieval.
Recent research approaches conversational search by simplified settings of
response ranking and conversational question answering, where an answer is
either selected from a given candidate set or extracted from a given passage.
These simplifications neglect the fundamental role of retrieval in
conversational search. To address this limitation, we introduce an
open-retrieval conversational question answering (ORConvQA) setting, where we
learn to retrieve evidence from a large collection before extracting answers,
as a further step towards building functional conversational search systems. We
create a dataset, OR-QuAC, to facilitate research on ORConvQA. We build an
end-to-end system for ORConvQA, featuring a retriever, a reranker, and a reader
that are all based on Transformers. Our extensive experiments on OR-QuAC
demonstrate that a learnable retriever is crucial for ORConvQA. We further show
that our system can make a substantial improvement when we enable history
modeling in all system components. Moreover, we show that the reranker
component contributes to the model performance by providing a regularization
effect. Finally, further in-depth analyses are performed to provide new
insights into ORConvQA.Comment: Accepted to SIGIR'2
Reversible Quantum Interface for Tunable Single-sideband Modulation
Using Electromagnetically Induced Transparency (EIT) in a Cesium vapor, we
demonstrate experimentally that the quantum state of a light beam can be mapped
into the long lived Zeeman coherences of an atomic ground state. Two
non-commuting variables carried by light are simultaneously stored and
subsequentely read-out, with no noise added. We compare the case where a
tunable single sideband is stored independently of the other one to the case
where the two symmetrical sidebands are stored using the same EIT transparency
window.Comment: 4 pages, 6 figure
Scalable quantum memory in the ultrastrong coupling regime
Circuit quantum electrodynamics, consisting of superconducting artificial
atoms coupled to on-chip resonators, represents a prime candidate to implement
the scalable quantum computing architecture because of the presence of good
tunability and controllability. Furthermore, recent advances have pushed the
technology towards the ultrastrong coupling regime of light-matter interaction,
where the qubit-resonator coupling strength reaches a considerable fraction of
the resonator frequency. Here, we propose a qubit-resonator system operating in
that regime, as a quantum memory device and study the storage and retrieval of
quantum information in and from the Z2 parity-protected quantum memory, within
experimentally feasible schemes. We are also convinced that our proposal might
pave a way to realize a scalable quantum random-access memory due to its fast
storage and readout performances.Comment: We have updated the title, abstract and included a new section on the
open-system dynamic
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