243 research outputs found
Towards the compression of parton densities through machine learning algorithms
One of the most fascinating challenges in the context of parton density
function (PDF) is the determination of the best combined PDF uncertainty from
individual PDF sets. Since 2014 multiple methodologies have been developed to
achieve this goal. In this proceedings we first summarize the strategy adopted
by the PDF4LHC15 recommendation and then, we discuss about a new approach to
Monte Carlo PDF compression based on clustering through machine learning
algorithms.Comment: 4 pages, 4 figures, to appear in the proceedings of 50th Rencontres
de Moriond, QCD and High Energy Interactions, La Thuile, Italy, March 201
Quantum Singular Value Decomposer
We present a variational quantum circuit that produces the Singular Value
Decomposition of a bipartite pure state. The proposed circuit, that we name
Quantum Singular Value Decomposer or QSVD, is made of two unitaries
respectively acting on each part of the system. The key idea of the algorithm
is to train this circuit so that the final state displays exact output
coincidence from both subsystems for every measurement in the computational
basis. Such circuit preserves entanglement between the parties and acts as a
diagonalizer that delivers the eigenvalues of the Schmidt decomposition. Our
algorithm only requires measurements in one single setting, in striking
contrast to the settings required by state tomography. Furthermore, the
adjoints of the unitaries making the circuit are used to create the
eigenvectors of the decomposition up to a global phase. Some further
applications of QSVD are readily obtained. The proposed QSVD circuit allows to
construct a SWAP between the two parties of the system without the need of any
quantum gate communicating them. We also show that a circuit made with QSVD and
CNOTs acts as an encoder of information of the original state onto one of its
parties. This idea can be reversed and used to create random states with a
precise entanglement structure.Comment: 6 + 1 pages, 5 figure
Platonic Entanglement
We present a construction of highly entangled states defined on the topology
of a platonic solid using tensor networks based on ancillary Absolute Maximally
Entangled (AME) states. We illustrate the idea using the example of a quantum
state based on AME(5,2) over a dodecahedron. We analyze the entropy of such
states on many different partitions, and observe that they come on integer
numbers and are almost maximal. We also observe that all platonic solids accept
the construction of AME states based on Reed-Solomon codes since their number
of facets, vertices and edges are always a prime number plus one.Comment: 6 pages, 3 figure
Absolutely Maximally Entangled states, combinatorial designs and multi-unitary matrices
Absolutely Maximally Entangled (AME) states are those multipartite quantum
states that carry absolute maximum entanglement in all possible partitions. AME
states are known to play a relevant role in multipartite teleportation, in
quantum secret sharing and they provide the basis novel tensor networks related
to holography. We present alternative constructions of AME states and show
their link with combinatorial designs. We also analyze a key property of AME,
namely their relation to tensors that can be understood as unitary
transformations in every of its bi-partitions. We call this property
multi-unitarity.Comment: 18 pages, 2 figures. Comments are very welcom
Operational approach to Bell inequalities: applications to qutrits
Bell inequalities can be studied both as constraints in the space of
probability distributions and as expectation values of multipartite operators.
The latter approach is particularly useful when considering outcomes as
eigenvalues of unitary operators. This brings the possibility of exploiting the
complex structure of the coefficients in the Bell operators. We investigate
this avenue of though in the known case of two outcomes, and find new Bell
inequalities for the cases of three outcomes and and parties. We
find their corresponding classical bounds and their maximum violation in the
case of qutrits. We further propose a novel way to generate Bell inequalities
based on a mapping from maximally entangled states to Bell operators and
produce examples for different outcomes and number of parties.Comment: 10 pages, no figures. A sign error in Eq.(10), appearing in the
published version, has been correcte
Quantum simulation of non-trivial topology
We propose several designs to simulate quantum many-body systems in manifolds
with a non-trivial topology. The key idea is to create a synthetic lattice
combining real-space and internal degrees of freedom via a suitable use of
induced hoppings. The simplest example is the conversion of an open spin-ladder
into a closed spin-chain with arbitrary boundary conditions. Further
exploitation of the idea leads to the conversion of open chains with internal
degrees of freedom into artificial tori and M\"obius strips of different kinds.
We show that in synthetic lattices the Hubbard model on sharp and scalable
manifolds with non-Euclidean topologies may be realized. We provide a few
examples of the effect that a change of topology can have on quantum systems
amenable to simulation, both at the single-particle and at the many-body level.Comment: 12 pages, 15 figure
Absolute Maximal Entanglement and Quantum Secret Sharing
We study the existence of absolutely maximally entangled (AME) states in
quantum mechanics and its applications to quantum information. AME states are
characterized by being maximally entangled for all bipartitions of the system
and exhibit genuine multipartite entanglement. With such states, we present a
novel parallel teleportation protocol which teleports multiple quantum states
between groups of senders and receivers. The notable features of this protocol
are that (i) the partition into senders and receivers can be chosen after the
state has been distributed, and (ii) one group has to perform joint quantum
operations while the parties of the other group only have to act locally on
their system. We also prove the equivalence between pure state quantum secret
sharing schemes and AME states with an even number of parties. This equivalence
implies the existence of AME states for an arbitrary number of parties based on
known results about the existence of quantum secret sharing schemes.Comment: 5 pages, 2 figure
Hype in Science Communication: Exploring Scientists' Attitudes and Practices in Quantum Physics
An interpretive phenomenological approach is adopted to investigate
scientists' attitudes and practices related to hype in science communication.
Twenty-four active quantum physicists participated in 5 focus groups. Through a
semi-structured questionnaire, their use of hype, attitudes, behaviours, and
perspectives on hype in science communication were observed. The main results
show that scientists primarily attribute hype generation to themselves, major
corporations, and marketing departments. They see hype as crucial for research
funding and use it strategically, despite concerns. Scientists view hype as
coercive, compromising their work's integrity, leading to mostly negative
feelings about it, except for collaborator-generated hype. A dissonance exists
between scientists' involvement in hype, their opinions, and the negative
emotions it triggers. They manage this by attributing responsibility to the
academic system, downplaying their practices. This reveals hype in science
communication as a calculated, persuasive tactic by academic stakeholders,
aligning with a neoliberal view of science. Implications extend to science
communication, media studies, regulation, and academia.Comment: 23 page
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