101 research outputs found
Experimental demonstration of the DPTS QKD protocol over a 170 km fiber link
Quantum key distribution (QKD) is a promising technology aiming at solving
the security problem arising from the advent of quantum computers. While the
main theoretical aspects are well developed today, limited performances, in
terms of achievable link distance and secret key rate, are preventing the
deployment of this technology on a large scale. More recent QKD protocols,
which use multiple degrees of freedom for the encoding of the quantum states,
allow an enhancement of the system performances. Here, we present the
experimental demonstration of the differential phase-time shifting protocol
(DPTS) up to 170 km of fiber link. We compare its performance with the
well-known coherent one-way (COW) and the differential phase shifting (DPS)
protocols, demonstrating a higher secret key rate up to 100 km. Moreover, we
propagate a classical signal in the same fiber, proving the compatibility of
quantum and classical light.Comment: 5 pages, 3 figures, journal pape
Orbital angular momentum states enabling fiber-based high-dimensional quantum communication
Quantum networks are the ultimate target in quantum communication, where many
connected users can share information carried by quantum systems. The keystones
of such structures are the reliable generation, transmission and manipulation
of quantum states. Two-dimensional quantum states, qubits, are steadily adopted
as information units. However, high-dimensional quantum states, qudits,
constitute a richer resource for future quantum networks, exceeding the
limitations imposed by the ubiquitous qubits. The generation and manipulation
of such -level systems have been improved over the last ten years, but their
reliable transmission between remote locations remains the main challenge.
Here, we show how a recent air-core fiber supporting orbital angular momentum
(OAM) modes can be exploited to faithfully transmit -dimensional states.
Four OAM quantum states and their superpositions are created, propagated in a
1.2 km long fiber and detected with high fidelities. In addition, three quantum
key distribution (QKD) protocols are implemented as concrete applications to
assert the practicality of our results. This experiment enhances the
distribution of high-dimensional quantum states, attesting the orbital angular
momentum as vessel for the future quantum network
Experimental generalized quantum suppression law in Sylvester interferometers
Photonic interference is a key quantum resource for optical quantum
computation, and in particular for so-called boson sampling machines. In
interferometers with certain symmetries, genuine multiphoton quantum
interference effectively suppresses certain sets of events, as in the original
Hong-Ou-Mandel effect. Recently, it was shown that some classical and
semi-classical models could be ruled out by identifying such suppressions in
Fourier interferometers. Here we propose a suppression law suitable for
random-input experiments in multimode Sylvester interferometers, and verify it
experimentally using 4- and 8-mode integrated interferometers. The observed
suppression is stronger than what is observed in Fourier interferometers of the
same size, and could be relevant to certification of boson sampling machines
and other experiments relying on bosonic interference.Comment: 5 pages, 3 figures + 11 pages, 3 figures Supplementary Informatio
Air-core fiber distribution of hybrid vector vortex-polarization entangled states
Entanglement distribution between distant parties is one of the most
important and challenging tasks in quantum communication. Distribution of
photonic entangled states using optical fiber links is a fundamental building
block towards quantum networks. Among the different degrees of freedom, orbital
angular momentum (OAM) is one of the most promising due to its natural
capability to encode high dimensional quantum states. In this article, we
experimentally demonstrate fiber distribution of hybrid polarization-vector
vortex entangled photon pairs. To this end, we exploit a recently developed
air-core fiber which supports OAM modes. High fidelity distribution of the
entangled states is demonstrated by performing quantum state tomography in the
polarization-OAM Hilbert space after fiber propagation, and by violations of
Bell inequalities and multipartite entanglement tests. The present results open
new scenarios for quantum applications where correlated complex states can be
transmitted by exploiting the vectorial nature of light
Calcium-sensing receptor and calcium kidney stones
Calcium nephrolithiasis may be considered as a complex disease having multiple pathogenetic mechanisms and characterized by various clinical manifestations. Both genetic and environmental factors may increase susceptibility to calcium stones; therefore, it is crucial to characterize the patient phenotype to distinguish homogeneous groups of stone formers. Family and twin studies have shown that the stone transmission pattern is not mendelian, but complex and polygenic. In these studies, heritability of calcium stones was calculated around 50
Path-encoded high-dimensional quantum communication over a 2 km multicore fiber
Quantum key distribution (QKD) protocols based on high-dimensional quantum
states have shown the route to increase the key rate generation while
benefiting of enhanced error tolerance, thus overcoming the limitations of
two-dimensional QKD protocols. Nonetheless, the reliable transmission through
fiber links of high-dimensional quantum states remains an open challenge that
must be addressed to boost their application. Here, we demonstrate the reliable
transmission over a 2 km long multicore fiber of path-encoded high-dimensional
quantum states. Leveraging on a phase-locked loop system, a stable
interferometric detection is guaranteed, allowing for low error rates and the
generation of 6.3 Mbit/s of secret key rate.Comment: to appear in npj Quantum Informatio
Biliverdin Protects against Liver Ischemia Reperfusion Injury in Swine
Ischemia reperfusion injury (IRI) in organ transplantation remains a serious and unsolved problem. Organs that undergo significant damage during IRI, function less well immediately after reperfusion and tend to have more problems at later times when rejection can occur. Biliverdin has emerged as an agent that potently suppress IRI in rodent models. Since the use of biliverdin is being developed as a potential therapeutic modality for humans, we tested the efficacy for its effects on IRI of the liver in swine, an accepted and relevant pre-clinical animal model. Administration of biliverdin resulted in rapid appearance of bilirubin in the serum and significantly suppressed IRI-induced liver dysfunction as measured by multiple parameters including urea and ammonia clearance, neutrophil infiltration and tissue histopathology including hepatocyte cell death. Taken together, our findings, in a large animal model, provide strong support for the continued evaluation of biliverdin as a potential therapeutic in the clinical setting of transplantation of the liver and perhaps other organs
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