155 research outputs found
Self-consistent optimization of the -Expansion for meson decays
We discuss the self-consistency imposed by the analyticity of regular parts
of form factors, appearing in the -expansion for semileptonic -meson
decays, when fitted in different kinematic regions. Relying on the uniqueness
of functions defined by analytic continuation, we propose four metrics which
measure the departure from the ideal analytic self-consistency. We illustrate
the process using Belle data for . For this
specific example, the metrics provide consistent indications that some choices
(order of truncation, BGL or BCL) made in the form of the -expansion can be
optimized. However, other choices (-origin, location of isolated poles and
threshold constraints) appear to have very little effect on these metrics. We
briefly discuss the implication for optimization of the -expansion for
nucleon form factors relevant for neutrino oscillation experiments
Quantum mean estimation for lattice field theory
We demonstrate the quantum mean estimation algorithm on Euclidean lattice
field theories. This shows a quadratic advantage over Monte Carlo methods which
persists even in presence of a sign problem, and is insensitive to critical
slowing down. The algorithm is used to compute with and without a sign
problem, a toy U(1) gauge theory model, and the Ising model. The effect of
-gate synthesis errors on a future fault-tolerant quantum computer is
investigated.Comment: 14 pages, 18 figure
Automatic Evaluation of Turn-taking Cues in Conversational Speech Synthesis
Turn-taking is a fundamental aspect of human communication where speakers
convey their intention to either hold, or yield, their turn through prosodic
cues. Using the recently proposed Voice Activity Projection model, we propose
an automatic evaluation approach to measure these aspects for conversational
speech synthesis. We investigate the ability of three commercial, and two
open-source, Text-To-Speech (TTS) systems ability to generate turn-taking cues
over simulated turns. By varying the stimuli, or controlling the prosody, we
analyze the models performances. We show that while commercial TTS largely
provide appropriate cues, they often produce ambiguous signals, and that
further improvements are possible. TTS, trained on read or spontaneous speech,
produce strong turn-hold but weak turn-yield cues. We argue that this approach,
that focus on functional aspects of interaction, provides a useful addition to
other important speech metrics, such as intelligibility and naturalness.Comment: Accepted at INTERSPEECH 2023, 5 pages, 2 figures, 4 table
Applying NOX Error Mitigation Protocols to Calculate Real-time Quantum Field Theory Scattering Phase Shifts
Real-time scattering calculations on a Noisy Intermediate Scale Quantum
(NISQ) quantum computer are disrupted by errors that accumulate throughout the
circuits. To improve the accuracy of such physics simulations, one can
supplement the application circuits with a recent error mitigation strategy
known as Noisy Output eXtrapolation (NOX). We tested these error mitigation
protocols on a Transverse Field Ising model and improved upon previous
calculations of the phase shift. Our proof-of-concept 4-qubit application
circuits were run on several IBM quantum computing hardware architectures.
Metrics were introduced that show between 21\% and 74\% error reduction for
circuit depths ranging from 14 to 37 hard cycles, confirming that the NOX
technique applies to circuits with a broad range of failure rates. This
observation on different cloud-accessible devices further confirms that NOX
provides performance improvements even in the advent where circuits are
executed in substantially time-separated batches. Finally, we provide a
heuristic method to obtain systematic error bars on the mitigated results,
compare them with empirical errors and discuss their effects on phase shift
estimates.Comment: 11 pages, 7 figure
Quantum Simulation of an Open System: A Dissipative 1+1D Ising Model
The 1+1D Ising model is an ideal benchmark for quantum algorithms, as it is
very well understood theoretically. This is true even when expanding the model
to include complex coupling constants. In this work, we implement quantum
algorithms designed for the simulation of open or complex coupling quantum
field theories on IBM devices with a focus on the measurement of the Lee-Yang
edge singularity. This feature corresponds (at large volumes) to a phase
transition, and our successful reproduction of the transition represents a
non-trivial test for current hardware and its ability to distinguish features
of interest in quantum field theories.Comment: 9 pages, 9 figures, 2 table
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