673 research outputs found
The Thirring quantum cellular automaton
We analytically diagonalize a discrete-time on-site interacting fermionic
cellular automaton in the two-particle sector. Important features of the
solutions sensibly differ from those of analogous Hamiltonian models. In
particular, we found a wider variety of scattering processes, we have bound
states for every value of the total momentum, and there exist bound states also
in the free case, where the coupling constant is null.Comment: 4 pages+references, Revtex style, 2 figures, supplemental material
included as appendi
Optimal quantum tomography for states, measurements, and transformations
We present the first complete optimization of quantum tomography, for states,
POVMs, and various classes of transformations, for arbitrary prior ensemble and
arbitrary representation, giving corresponding feasible experimental schemes.Comment: 4 pages, 1 figur
Exergy Analysis of Thermal Energy Storage With Specific Remarks on the Variation of the Environmental Temperature
Causal structures and the classification of higher order quantum computations
Quantum operations are the most widely used tool in the theory of quantum
information processing, representing elementary transformations of quantum
states that are composed to form complex quantum circuits. The class of quantum
transformations can be extended by including transformations on quantum
operations, and transformations thereof, and so on up to the construction of a
potentially infinite hierarchy of transformations. In the last decade, a
sub-hierarchy, known as quantum combs, was exhaustively studied, and
characterised as the most general class of transformations that can be achieved
by quantum circuits with open slots hosting variable input elements, to form a
complete output quantum circuit. The theory of quantum combs proved to be
successful for the optimisation of information processing tasks otherwise
untreatable. In more recent years the study of maps from combs to combs has
increased, thanks to interesting examples showing how this next order of maps
requires entanglement of the causal order of operations with the state of a
control quantum system, or, even more radically, superpositions of alternate
causal orderings. Some of these non-circuital transformations are known to be
achievable and have even been achieved experimentally, and were proved to
provide some computational advantage in various information-processing tasks
with respect to quantum combs. Here we provide a formal language to form all
possible types of transformations, and use it to prove general structure
theorems for transformations in the hierarchy. We then provide a mathematical
characterisation of the set of maps from combs to combs, hinting at a route for
the complete characterisation of maps in the hierarchy. The classification is
strictly related to the way in which the maps manipulate the causal structure
of input circuits.Comment: 12 pages, revtex styl
DTPA-Functionalized silica-based monoliths for the removal of transition and lanthanide ions from aqueous phase
Transition and rare-earth metals are essential raw materials used in a wide range of technological applications; moreover, their consumption is often associated with high production of wastesÂ. Therefore, their recycling and recovery from end-of-life products or metal-contaminated aqueous environments is of considerable importance from a circular economy perspective. In our study, synthetic mesoporous silica monoliths, obtained by sol-gel synthesis[1] and functionalized with chelating groups are used for the recovery of metal ions from aqueous matrices (MONO-DTPA). The monoliths were characterized using a multi-technique approach and were tested in the recovery of paramagnetic Gd3+, Cu2+ and Co2+ ions from aqueous solutions, using 1H-NMR relaxometry to evaluate their uptake performance in real time and in simple conditions[2]. Detailed information on the kinetics of the capture process was also extrapolated. Finally, the possibility to regenerate the solid sorbents was evaluated. The modified silica monoliths were able to recover an appreciable amount of both di- and trivalent metal ions. The best results were obtained in the case of Cu2+ after 24 hours of contact, with a recovered amount of 0.29 mmol/g corresponding to 18.48 mg/g (Fig. 1, A).
The capture performance of MONO-DTPA has been shown to be superior to that of natural or synthetic materials commonly used for metal ion removal (Fig 1, B).
[1] V. Miglio, C. Zaccone, C. Vittoni, I. Braschi, E. Buscaroli, G. Golemme, L. Marchese and C. Bisio, Molecules 2021, 26, 1316
[2] S. Marchesi, S. Nascimbene, M. Guidotti, C. Bisio and F. Carniato, Dalton Trans. 2022, 51, 4502–4509
Optimal quantum learning of a unitary transformation
We address the problem of learning an unknown unitary transformation from a
finite number of examples. The problem consists in finding the learning machine
that optimally emulates the examples, thus reproducing the unknown unitary
maximum fidelity. Learning a unitary is equivalent to storing it in the state
of a quantum memory (the memory of the learning machine), and subsequently
retrieving it. We prove that, whenever the unknown unitary is drawn from a
group, the optimal strategy consists in a parallel call of the available uses
followed by a "measure-and-rotate" retrieving. Differing from the case of
quantum cloning, where the incoherent "measure-and-prepare" strategies are
typically suboptimal, in the case of learning the "measure-and-rotate" strategy
is optimal even when the learning machine is asked to reproduce a single copy
of the unknown unitary. We finally address the problem of the optimal inversion
of an unknown unitary evolution, showing also in this case the optimality of
the "measure-and-rotate" strategies and applying our result to the optimal
approximate realignment of reference frames for quantum communication.Comment: 7 pages, 1 figure, published versio
Multimedia content delivery for emerging satellite networks
Multimedia content delivery over satellite systems is considered as a promising service in the emerging networks. The aim of this work is to design a novel radio resource management (RRM) algorithm for efficiently managing multicast multimedia content transmission over satellite network. The proposed approach performs the spectrum management on a per-group basis, by splitting multicast terminals into different subgroups according to the experienced channel qualities. We demonstrate that subgrouping policy defined by the authors as multicast subgrouping-maximum satisfaction index (MS-MSI), is based on a new metric (i.e., MSI), which overcomes the weakness of the previous techniques proposed in literature and provides the best trade-off between user throughput and fairness. As a further result, we demonstrate that MS-MSI is robust to the long propagation delay of satellite links. An extensive simulation campaign has been conducted by considering several satellite environments
Impregnation of Synthetic Saponites with Aldehydes: A Green Approach in the Intercalation of Bioactive Principles
06N-P63\u3b1 and TA-P63\u3b1 exhibit intrinsic differences in transactivation specificities that depend on distinct features of DNA target sites.
TP63 is a member of the TP53 gene family that encodes for up to ten different TA
and 06N isoforms through alternative promoter usage and alternative splicing.
Besides being a master regulator of gene expression for squamous epithelial
proliferation, differentiation and maintenance, P63, through differential
expression of its isoforms, plays important roles in tumorigenesis. All P63
isoforms share an immunoglobulin-like folded DNA binding domain responsible for
binding to sequence-specific response elements (REs), whose overall consensus
sequence is similar to that of the canonical p53 RE. Using a defined assay in
yeast, where P63 isoforms and RE sequences are the only variables, and gene
expression assays in human cell lines, we demonstrated that human TA- and 06N-P63\u3b1
proteins exhibited differences in transactivation specificity not observed with
the corresponding P73 or P53 protein isoforms. These differences 1) were
dependent on specific features of the RE sequence, 2) could be related to
intrinsic differences in their oligomeric state and cooperative DNA binding, and
3) appeared to be conserved in evolution. Since genotoxic stress can change
relative ratio of TA- and 06N-P63\u3b1 protein levels, the different transactivation
specificity of each P63 isoform could potentially influence cellular responses to
specific stresses
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