586 research outputs found
The reactor antineutrino anomaly and low energy threshold neutrino experiments
Short distance reactor antineutrino experiments measure an antineutrino
spectrum a few percent lower than expected from theoretical predictions. In
this work we study the potential of low energy threshold reactor experiments in
the context of a light sterile neutrino signal. We discuss the perspectives of
the recently detected coherent elastic neutrino-nucleus scattering in future
reactor antineutrino experiments. We find that the expectations to improve the
current constraints on the mixing with sterile neutrinos are promising. We also
analyse the measurements of antineutrino scattering off electrons from short
distance reactor experiments. In this case, the statistics is not competitive
with inverse beta decay experiments, although future experiments might play a
role when compare it with the Gallium anomaly.Comment: 9 pages, 6 figures, 1 table, matches published versio
Quantum key distribution session with 16-dimensional photonic states
The secure transfer of information is an important problem in modern
telecommunications. Quantum key distribution (QKD) provides a solution to this
problem by using individual quantum systems to generate correlated bits between
remote parties, that can be used to extract a secret key. QKD with
D-dimensional quantum channels provides security advantages that grow with
increasing D. However, the vast majority of QKD implementations has been
restricted to two dimensions. Here we demonstrate the feasibility of using
higher dimensions for real-world quantum cryptography by performing, for the
first time, a fully automated QKD session based on the BB84 protocol with
16-dimensional quantum states. Information is encoded in the single-photon
transverse momentum and the required states are dynamically generated with
programmable spatial light modulators. Our setup paves the way for future
developments in the field of experimental high-dimensional QKD.Comment: 8 pages, 3 figure
Playing dice with the universe: Bayesian statistical analyses of cosmological models and new observables
The ultimate goal of cosmologists is to find a cosmological model able to explain the current observational data. In this sense, the Standard Cosmological model establishes that our universe is mainly composed of two unknown components: a type of matter that is known to only interact through gravitation, Cold Dark Matter, and a substance responsible for the current accelerated expansion of the universe that can be modelled by a cosmological constant. Still, this model, though successful, fails to answer hot-burning questions in the field. For this reason, theoretical cosmologists focus on developing further modifications of the model to test them against astrophysical data and check whether alternative scenarios can provide a better explanation of the observations.This thesis is dedicated to the Bayesian statistical analyses of extensions of the Standard Cosmological model using several astronomical data sets, and to the forecast of new observables and experiments. The first part focuses on data science and inflation, and it aims to constrain inflationary models using advanced inference techniques. The second part of the thesis is dedicated to the novel concept of cross-correlations of gravitational-wave physics and large scale structure observables. The third part of this thesis is dedicated to the incoming ESA Euclid satellite, and in particular, it focuses on a crucial data science analysis software for the mission: the code “Cosmological Likelihood for Observables in Euclid”, also known as CLOE.Theoretical Physic
High-dimensional decoy-state quantum key distribution over 0.3 km of multicore telecommunication optical fibers
Multiplexing is a strategy to augment the transmission capacity of a
communication system. It consists of combining multiple signals over the same
data channel and it has been very successful in classical communications.
However, the use of enhanced channels has only reached limited practicality in
quantum communications (QC) as it requires the complex manipulation of quantum
systems of higher dimensions. Considerable effort is being made towards QC
using high-dimensional quantum systems encoded into the transverse momentum of
single photons but, so far, no approach has been proven to be fully compatible
with the existing telecommunication infrastructure. Here, we overcome such a
technological challenge and demonstrate a stable and secure high-dimensional
decoy-state quantum key distribution session over a 0.3 km long multicore
optical fiber. The high-dimensional quantum states are defined in terms of the
multiple core modes available for the photon transmission over the fiber, and
the decoy-state analysis demonstrates that our technique enables a positive
secret key generation rate up to 25 km of fiber propagation. Finally, we show
how our results build up towards a high-dimensional quantum network composed of
free-space and fiber based linksComment: Please see the complementary work arXiv:1610.01812 (2016
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