47 research outputs found
Mode-pairing quantum key distribution with advantage distillation
Mode-pairing quantum key distribution (MP-QKD) is an easy-to-implement scheme
that transcends the Pirandola--Laurenza--Ottaviani--Banchi bound without using
quantum repeaters. In this paper, we present an improvement of the performance
of MP-QKD using an advantage distillation method. The simulation results
demonstrate that the proposed scheme extends the transmission distance
significantly with a channel loss exceeding 7.6 dB. Moreover, the scheme
tolerates a maximum quantum bit error rate of 8.9%, which is nearly twice that
of the original MP-QKD. In particular, as the system misalignment error
increases, the expandable distance of the proposed scheme also increases. The
proposed system is expected to promote the practical implementation of MP-QKD
in a wide range of applications, particularly in scenarios involving high
channel losses and system errors
Experimental quantum key distribution with source flaws
Decoy-state quantum key distribution (QKD) is a standard technique in current
quantum cryptographic implementations. Unfortunately, existing experiments have
two important drawbacks: the state preparation is assumed to be perfect without
errors and the employed security proofs do not fully consider the finite-key
effects for general attacks. These two drawbacks mean that existing experiments
are not guaranteed to be secure in practice. Here, we perform an experiment
that for the first time shows secure QKD with imperfect state preparations over
long distances and achieves rigorous finite-key security bounds for decoy-state
QKD against coherent attacks in the universally composable framework. We
quantify the source flaws experimentally and demonstrate a QKD implementation
that is tolerant to channel loss despite the source flaws. Our implementation
considers more real-world problems than most previous experiments and our
theory can be applied to general QKD systems. These features constitute a step
towards secure QKD with imperfect devices.Comment: 12 pages, 4 figures, updated experiment and theor
Experimental Quantum Fingerprinting
Quantum communication holds the promise of creating disruptive technologies
that will play an essential role in future communication networks. For example,
the study of quantum communication complexity has shown that quantum
communication allows exponential reductions in the information that must be
transmitted to solve distributed computational tasks. Recently, protocols that
realize this advantage using optical implementations have been proposed. Here
we report a proof of concept experimental demonstration of a quantum
fingerprinting system that is capable of transmitting less information than the
best known classical protocol. Our implementation is based on a modified
version of a commercial quantum key distribution system using off-the-shelf
optical components over telecom wavelengths, and is practical for messages as
large as 100 Mbits, even in the presence of experimental imperfections. Our
results provide a first step in the development of experimental quantum
communication complexity.Comment: 11 pages, 6 Figure
Resource-efficient quantum key distribution with integrated silicon photonics
Integrated photonics provides a promising platform for quantum key
distribution (QKD) system in terms of miniaturization, robustness and
scalability. Tremendous QKD works based on integrated photonics have been
reported. Nonetheless, most current chip-based QKD implementations require
additional off-chip hardware to demodulate quantum states or perform auxiliary
tasks such as time synchronization and polarization basis tracking. Here, we
report a demonstration of resource-efficient chip-based BB84 QKD with a
silicon-based encoder and decoder. In our scheme, the time synchronization and
polarization compensation are implemented relying on the preparation and
measurement of the quantum states generated by on-chip devices, thus no need
additional hardware. The experimental tests show that our scheme is highly
stable with a low intrinsic QBER of in a 6-h continuous run.
Furthermore, over a commercial fiber channel up to 150 km, the system enables
realizing secure key distribution at a rate of 866 bps. Our demonstration paves
the way for low-cost, wafer-scale manufactured QKD system.Comment: comments are welcome
Experimental quantum key distribution secure against malicious devices
The fabrication of quantum key distribution (QKD) systems typically involves
several parties, thus providing Eve with multiple opportunities to meddle with
the devices. As a consequence, conventional hardware and/or software hacking
attacks pose natural threats to the security of practical QKD. Fortunately, if
the number of corrupted devices is limited, the security can be restored by
using redundant apparatuses. Here, we report on the demonstration of a secure
QKD setup with optical devices and classical post-processing units possibly
controlled by an eavesdropper. We implement a 1.25 GHz chip-based
measurement-device-independent QKD system secure against malicious devices on
\emph{both} the measurement and the users' sides. The secret key rate reaches
137 bps over a 24 dB channel loss. Our setup, benefiting from high clock rate,
miniaturized transmitters and a cost-effective structure, provides a promising
solution for widespread applications requiring uncompromising communication
security.Comment: 28 pages, 5 figures, 4 table
High-speed measurement-device-independent quantum key distribution with integrated silicon photonics
Measurement-device-independent quantum key distribution (MDI-QKD) removes all
detector side channels and enables secure QKD with an untrusted relay. It is
suitable for building a star-type quantum access network, where the complicated
and expensive measurement devices are placed in the central untrusted relay and
each user requires only a low-cost transmitter, such as an integrated photonic
chip. Here, we experimentally demonstrate a 1.25 GHz silicon photonic
chip-based MDI-QKD system using polarization encoding. The photonic chip
transmitters integrate the necessary encoding components for a standard QKD
source. We implement random modulations of polarization states and decoy
intensities, and demonstrate a finite-key secret rate of 31 bps over 36 dB
channel loss (or 180 km standard fiber). This key rate is higher than
state-of-the-art MDI-QKD experiments. The results show that silicon photonic
chip-based MDI-QKD, benefiting from miniaturization, low-cost manufacture and
compatibility with CMOS microelectronics, is a promising solution for future
quantum secure networks.Comment: 30 pages, 12 figure
Th-MYCN Mice with Caspase-8 Deficiency Develop Advanced Neuroblastoma with Bone Marrow Metastasis
Neuroblastoma, the most common extracranial pediatric solid tumor, is responsible for 15% of all childhood cancer deaths. Patients frequently present at diagnosis with metastatic disease, particularly to the bone marrow (BM). Advances in therapy and understanding of the metastatic process have been limited due in part, to the lack of animal models harboring BM disease. The widely employed transgenic model, the Th-MYCN mouse, exhibits limited metastasis to this site. Here we establish the first genetic immunocompetent mouse model for metastatic neuroblastoma with enhanced secondary tumors in the BM. This model recapitulates two frequent alterations in metastatic neuroblasoma, over-expression of MYCN and loss of caspase-8 expression. Mouse caspase-8 gene was deleted in neural crest lineage cells by crossing a Th-Cre transgenic mouse with a caspase-8 conditional knockout mouse. This mouse was then crossed with the neuroblastoma prone Th-MYCN mouse. While over-expression of MYCN by itself rarely caused bone marrow metastasis, combining MYCN overexpression and caspase-8 deletion significantly enhanced BM metastasis (37% incidence). Microarray expression studies of the primary tumors mRNAs and microRNAs revealed extracellular matrix (ECM) structural changes, increased expression of genes involved in epithelial to mesenchymal transition, inflammation and down-regulation of miR-7a and miR-29b. These molecular changes have been shown to be associated with tumor progression and activation of the cytokine transforming growth factor beta (TGF-β) pathway in various tumor models. Cytokine TGF-β can preferentially promote single cell motility and blood borne metastasis and therefore activation of this pathway may explain the enhanced BM metastasis observed in this animal model.Fil: Teitz, Tal. St. Jude Children’s Research Hospital. Department of Tumor Cell Biology; Estados UnidosFil: Inoue, Madoka. St. Jude Children’s Research Hospital. Department of Tumor Cell Biology; Estados UnidosFil: Valentine, Marcus B.. St. Jude Children’s Research Hospital. Department of Tumor Cell Biology; Estados UnidosFil: Zhu, Kejin. St. Jude Children’s Research Hospital. Department of Tumor Cell Biology; Estados UnidosFil: Rehg, Jerold E.. St. Jude Children’s Research Hospital. Department of Pathology; Estados UnidosFil: Zhao, Wei. St. Jude Children’s Research Hospital. Department of Biostatistics; Estados UnidosFil: Finkelstein, David. St. Jude Children’s Research Hospital. Department of Computational Biology; Estados UnidosFil: Wang, Yong-Dong. St. Jude Children’s Research Hospital. Hartwell Center for Bioinformatics and Biotechnology; Estados UnidosFil: Johnson, Melissa D.. St. Jude Children’s Research Hospital. Animal Imaging Center; Estados UnidosFil: Calabrese, Christopher. St. Jude Children’s Research Hospital. Animal Imaging Center; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Investigaciones en IngenierĂa GenĂ©tica y BiologĂa Molecular; ArgentinaFil: Hakem, Razqallah. University of Toronto. Ontario Cancer Institute. Department of Medical Biophysics; CanadáFil: Weiss, William A.. University of California. Departments of Neurology, Pediatrics and Neurological Surgery; Estados UnidosFil: Lahti, Jill M.. St. Jude Children’s Research Hospital. Department of Tumor Cell Biology; Estados Unido