1,869 research outputs found
The millimeter and submillimeter laboratory spectrum of methyl formate in its ground symmetric torsional state
Over 200 rotational lines of methyl formate in its ground (v-t = 0), symmetric (A) torsional state have been measured in the frequency range 140-550 GHz. Analysis of these and lower frequency transitions permits accurate prediction (≤0.1 MHz) of over 10,000 transitions at frequencies below 600 GHz with angular momentum J ≤ 50. The measured spectral lines have permitted identification of over 100 new methyl formate lines in Orion
Entanglement Wedge Reconstruction via Universal Recovery Channels
We apply and extend the theory of universal recovery channels from quantum
information theory to address the problem of entanglement wedge reconstruction
in AdS/CFT. It has recently been proposed that any low-energy local bulk
operators in a CFT boundary region's entanglement wedge can be reconstructed on
that boundary region itself. Existing work arguing for this proposal relies on
algebraic consequences of the exact equivalence between bulk and boundary
relative entropies, namely the theory of operator algebra quantum error
correction. However, bulk and boundary relative entropies are only
approximately equal in bulk effective field theory, and in similar situations
it is known that predictions from exact entropic equalities can be
qualitatively incorrect. The framework of universal recovery channels provides
a robust demonstration of the entanglement wedge reconstruction conjecture in
addition to new physical insights. Most notably, we find that a bulk operator
acting in a given boundary region's entanglement wedge can be expressed as the
response of the boundary region's modular Hamiltonian to a perturbation of the
bulk state in the direction of the bulk operator. This formula can be
interpreted as a noncommutative version of Bayes' rule that attempts to undo
the noise induced by restricting to only a portion of the boundary, and has an
integral representation in terms of modular flows. To reach these conclusions,
we extend the theory of universal recovery channels to finite-dimensional
operator algebras and demonstrate that recovery channels approximately preserve
the multiplicative structure of the operator algebra.Comment: 16 pages, 3 figures. v4: Generalized approximate recovery of 2-point
functions to arbitrary correlation functions. Clarified relation to previous
work. Added Geoffrey Penington as co-autho
Use of Radioactive Antibodies for Characterizing Antigens and Application to the Study of Flagella Synthesis
A simple rapid immunochemical procedure has been developed which provides information about the qualitative and quantitative nature of antigens. It involves the use of purified radioactive (^(125)I-labeled) antibodies. The amount of antibody bound to the antigen is determined by filtering the mixture through diethylaminoethyl (DEAE)-cellulose paper. All of the antigen, as well as the antibody complexed with it, is trapped on the paper, whereas free antibody is removed by repeated washing. This technique has been applied to the study of three immune systems, bovine serum albumin, Escherichia coli tryptophan synthetase B protein, and Bacillus subtilis flagella. The results obtained by the DEAE-antibody binding technique were comparable, in terms of sensitivity, specificity, and accuracy, to data obtained by microcomplement fixation and precipitin methods. The assay was used to measure the kinetics of flagella regeneration in B. subtilis
The laboratory millimeter-wave spectrum of methyl formate in its ground torsional E state
Over 250 rotational transitions of the internal rotor methyl formate (HCOOCH_3) in its ground v_t = 0 degenerate (E) torsional substate have been measured in the millimeter-wave spectral region. These data and a number of E-state lines identified by several other workers have been analyzed using an extension of the classical principal-axis method in the high barrier limit. The resulting rotational constants allow accurate prediction of the v_t = 0 E substate methyl formate spectrum below 300 GHz between states with angular momentum J ≤ 30 and rotational energy E_(rot)≤ 350cm^(-1). The calculated transition frequencies for the E state, when combined with the results of the previous analysis of the ground-symmetric, nondegenerate state, account for over 200 of the emission lines observed toward Orion in a recent survey of the 215-265 GHz band
TB or not TB? Acoustic cough analysis for tuberculosis classification
In this work, we explore recurrent neural network architectures for
tuberculosis (TB) cough classification. In contrast to previous unsuccessful
attempts to implement deep architectures in this domain, we show that a basic
bidirectional long short-term memory network (BiLSTM) can achieve improved
performance. In addition, we show that by performing greedy feature selection
in conjunction with a newly-proposed attention-based architecture that learns
patient invariant features, substantially better generalisation can be achieved
compared to a baseline and other considered architectures. Furthermore, this
attention mechanism allows an inspection of the temporal regions of the audio
signal considered to be important for classification to be performed. Finally,
we develop a neural style transfer technique to infer idealised inputs which
can subsequently be analysed. We find distinct differences between the
idealised power spectra of TB and non-TB coughs, which provide clues about the
origin of the features in the audio signal.Comment: Accepted for publication at Interspeech 202
Entanglement wedge reconstruction using the Petz map
At the heart of recent progress in AdS/CFT is the question of subregion duality, or entanglement wedge reconstruction: which part(s) of the boundary CFT are dual to a given subregion of the bulk? This question can be answered by appealing to the quantum error correcting properties of holography, and it was recently shown that robust bulk (entanglement wedge) reconstruction can be achieved using a universal recovery channel known as the twirled Petz map. In short, one can use the twirled Petz map to recover bulk data from a subset of the boundary. However, this map involves an averaging procedure over bulk and boundary modular time, and hence it can be somewhat intractable to evaluate in practice. We show that a much simpler channel, the Petz map, is sufficient for entanglement wedge reconstruction for any code space of fixed finite dimension — no twirling is required. Moreover, the error in the reconstruction will always be non-perturbatively small. From a quantum information perspective, we prove a general theorem extending the use of the Petz map as a general-purpose recovery channel to subsystem and operator algebra quantum error correction
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