36 research outputs found
Quantum JPEG
The JPEG algorithm compresses a digital image by filtering its high
spatial-frequency components. Similarly, we introduce a quantum protocol that
uses the quantum Fourier transform to discard the high-frequency qubits of an
image, downsampling it to a lower resolution. This allows to capture, compress
and send images even with limited quantum resources for storage and
communication. We show under which conditions this protocol is advantageous
with respect to its classical counterpart.Comment: 10 pages, 7 figures; [v2] Minor corrections and improvement
Pauli transfer matrix direct reconstruction: channel characterization without full process tomography
We present a tomographic protocol for the characterization of multiqubit
quantum channels. We discuss a specific class of input states, for which the
set of Pauli measurements at the output of the channel directly relates to its
Pauli transfer matrix components. We compare our results to those of standard
quantum process tomography, showing an exponential reduction in the number of
different experimental configurations required by a single matrix element
extraction, while keeping the same number of shots. This paves the way for more
efficient experimental implementations, whenever a selective knowledge of the
Pauli transfer matrix is needed. We provide several examples and simulations.Comment: 9 pages, 5 figures; [v2] Minor improvements and correction
A clinical trial of oral hyposensitization in systemic allergy to nickel.
Nickel allergy is the most common contact allergy. Some nickel-sensitive patients present systemic (cutaneous and/or digestive) symptoms related to the ingestion of high nickel-content foods, which significantly improve after a specific low nickel-content diet. The etiopathogenetic role of nickel in the genesis of systemic disorders is, furthermore, demonstrated by the relapse of previous contact lesions, appearance of widespread eczema and generalized urticaria-like lesions after oral nickel challenge test. The aim of this study is to investigate the safety and efficacy of a specific oral hyposensitization to nickel in patients with both local contact disorders and systemic symptoms after the ingestion of nickel-containing foods. Inclusion criteria for the recruitment of these patients were (other than a positive patch test) a benefit higher than 80% from a low nickel-content diet and a positive oral challenge with nickel. Based on the previous experiences, our group adopted a therapeutic protocol by using increasing oral doses of nickel sulfate associated to an elimination diet. Results have been excellent: this treatment has been effective in inducing clinical tolerance to nickel-containing foods, with a low incidence of side effects (gastric pyrosis, itching erythema)