124 research outputs found
Generation Engineering of Heralded Narrowband Colour Entangled States
Efficient heralded generation of entanglement together with its manipulation
is of great importance for quantum communications. In addition, states
generated with bandwidths naturally compatible with atomic transitions allow a
more efficient mapping of light into matter which is an essential requirement
for long distance quantum communications. Here we propose a scheme where the
indistinguishability between two spontaneous four-wave mixing processes is
engineered to herald generation of single-photon frequency-bin entangled
states, i.e., single-photons shared by two distinct frequency modes. We show
that entanglement can be optimised together with the generation probability,
while maintaining absorption negligible. Besides, the scheme illustrated for
cold rubidium atoms is versatile and can be implemented in several other
physical systems
Un inedito inventario della collezione di antichità appartenuta a Cesare Nichesola a Ponton
L'inedito verbale di requisizione delle epigrafi di Cesare Nichesola stilato da Gian Giacomo Giusti nel 1612 consente di ampliare notevolmente la conoscenza dell'antica collezione di antichità in parte confluita nel museo maffeiano
Nonlinear Interferometry via Fock State Projection
We use a photon-number resolving detector to monitor the photon number
distribution of the output of an interferometer, as a function of phase delay.
As inputs we use coherent states with mean photon number up to seven. The
postselection of a specific Fock (photon-number) state effectively induces
high-order optical non-linearities. Following a scheme by Bentley and Boyd
[S.J. Bentley and R.W. Boyd, Optics Express 12, 5735 (2004)] we explore this
effect to demonstrate interference patterns a factor of five smaller than the
Rayleigh limit.Comment: 4 pages, 5 figure
Single-photon excitation of a coherent state: catching the elementary step of stimulated light emission
When a single quantum of electromagnetic field excitation is added to the
same spatio-temporal mode of a coherent state, a new field state is generated
that exhibits intermediate properties between those of the two parents. Such a
single-photon-added coherent state is obtained by the action of the photon
creation operator on a coherent state and can thus be regarded as the result of
the most elementary excitation process of a classical light field. Here we
present and describe in depth the experimental realization of such states and
their complete analysis by means of a novel ultrafast, time-domain, quantum
homodyne tomography technique clearly revealing their non-classical character.Comment: 9 pages, 9 figures. Accepted for publication in Phys. Rev.
Tomographic test of Bell's inequality for a time-delocalized single photon
Time-domain balanced homodyne detection is performed on two well-separated
temporal modes sharing a single photon. The reconstructed density matrix of the
two-mode system is used to prove and quantify its entangled nature, while the
Wigner function is employed for an innovative tomographic test of Bell's
inequality based on the theoretical proposal by Banaszek and Wodkiewicz [Phys.
Rev. Lett. 82, 2009 (1999)]. Provided some auxiliary assumptions are made, a
clear violation of Banaszek-Bell's inequality is found.Comment: 7 pages, 3 figures: revised version with additional material;
accepetd for publication in Phys. Rev.
Per Marco Marchetti pittore di pale d’altare nella Faenza della Controriforma e alcuni disegni in rapporto con il "Martirio di Santa Caterina" in Sant’Antonio
La pala con il Martirio di Santa Caterina di Marco Marchetti risulta in rapporto con alcuni disegni inediti di Marco Marchetti agli Uffizi. Vengono presentate considerazioni sull'ambiente artistico faentino dell'epoca della Controriforma
Towards higher precision and operational use of optical homodyne tomograms
We present the results of an operational use of experimentally measured
optical tomograms to determine state characteristics (purity) avoiding any
reconstruction of quasiprobabilities. We also develop a natural way how to
estimate the errors (including both statistical and systematic ones) by an
analysis of the experimental data themselves. Precision of the experiment can
be increased by postselecting the data with minimal (systematic) errors. We
demonstrate those techniques by considering coherent and photon-added coherent
states measured via the time-domain improved homodyne detection. The
operational use and precision of the data allowed us to check for the first
time purity-dependent uncertainty relations and uncertainty relations for
Shannon and R\'{e}nyi entropies.Comment: 11 pages, 6 figures, 1 table, some results are extende
PHENOTYPIC AND MOLECULAR CHARACTERIZATION OF V. VULNIFI-CUS STRAINS FROM THE ADRIATIC SEA
Vibrio vulnificus, is an ubiquitous marine bacterium responsible of human food-borne disease and wound infection. Notwithstanding the great severity of the cases of septicaemia (with up to 50% of mortality), the incidence of disease is relatively low, probably as a consequence of different virulence characteristics of the strains. At present V. vulnificus is divided into three distinct biotypes (BT): BT1 and BT3 strains cause human disease, while B2 strains infects primarily eels. The present study represent a first attempt to investigate the complete characterization of environmental strains isolated from molluscan shellfish of the North-West Adriatic Sea
Robustness of raw quantum tomography
We scrutinize the effects of non-ideal data acquisition on the homodyne
tomograms of photon quantum states. The presence of a weight function,
schematizing the effects of the finite thickness of the probing beam or
equivalently noise, only affects the state reconstruction procedure by a
normalization constant. The results are extended to a discrete mesh and show
that quantum tomography is robust under incomplete and approximate knowledge of
tomograms.Comment: 7 pages, 1 figure, published versio
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