394 research outputs found
Experimental demonstration of the criterion for the prepare-and-measure nonlocality
The prepare-and-measure theory is a new type of quantum paradox that reveals
the incompatibility between classical theory and quantum mechanics in terms of
the dimensionality of physical systems.
Just as the Horodecki criterion can determine whether given quantum states
are capable of exhibiting Bell nonclassicality, a similar criterion is needed
for the prepare-and-measure theory to determine whether given quantum states
can exhibit the prepare-and-measure nonclassicality.Recently, Poderini \emph{et
al.} [Phys. Rev. Research 2, 043106 (2020)] presented such a criterion for the
prepare-and-measure nonclassicality.In this work, we experimentally validate
this criterion -- 52 different sets of quantum states are prepared and tested
one by one using this criterion to determine whether they can exhibit the
prepare-and-measure nonclassicality, and the experimental results are in good
agreement with the theoretical expectations.
The criterion experimentally verified here has the potential to be widely
used in future research on the prepare-and-measure nonclassicality
High-Dimensional Quantum Key Distribution based on Multicore Fiber using Silicon Photonic Integrated Circuits
Quantum Key Distribution (QKD) provides an efficient means to exchange
information in an unconditionally secure way. Historically, QKD protocols have
been based on binary signal formats, such as two polarisation states, and the
transmitted information efficiency of the quantum key is intrinsically limited
to 1 bit/photon. Here we propose and experimentally demonstrate, for the first
time, a high-dimensional QKD protocol based on space division multiplexing in
multicore fiber using silicon photonic integrated lightwave circuits. We
successfully realized three mutually unbiased bases in a four-dimensional
Hilbert space, and achieved low and stable quantum bit error rate well below
both coherent attack and individual attack limits. Compared to previous
demonstrations, the use of a multicore fiber in our protocol provides a much
more efficient way to create high-dimensional quantum states, and enables
breaking the information efficiency limit of traditional QKD protocols. In
addition, the silicon photonic circuits used in our work integrate variable
optical attenuators, highly efficient multicore fiber couplers, and
Mach-Zehnder interferometers, enabling manipulating high-dimensional quantum
states in a compact and stable means. Our demonstration pave the way to utilize
state-of-the-art multicore fibers for long distance high-dimensional QKD, and
boost silicon photonics for high information efficiency quantum communications.Comment: Please see the complementary work arXiv:1610.01682 (2016
Quantum state transfer between photons preloaded with quantum information
Quantum mechanics provides a ``disembodied'' way to transfer an unknown
quantum state from one quantum system to another. However, all experiments of
quantum state transfer to date are limited to cases where the target quantum
system contains no prior quantum information. Here we propose a scheme for
transferring a quantum state to a quantum system preloaded with quantum
information. By using an optical qubit-ququart entangling gate, we have
experimentally demonstrated this new protocol -- transferring a qubit to a
photon preloaded with one qubit of quantum information. After the state
transfer, the target photon contains two qubits of quantum information, one
from the qubit being transferred and the other from the pre-existing qubit.
Furthermore, we have also experimentally realized the inverse operation of the
aforementioned quantum state transfer, which is called the partial quantum
state transfer, namely transferring one qubit of quantum information from a
photon preloaded with two qubits of quantum information to another photon. The
fidelities of the quantum state transfer range from to , all
above the classical limit of . Our work sheds light on a new direction for
quantum state transfer and demonstrates our ability to implement entangling
operations beyond two-level quantum systems.Comment: 22pages, 9 figure
Modeling Human Performance on Statistical Word Segmentation Tasks
Harnessing the orbital angular momentum (OAM) of light is an appealing approach to developing photonic technologies for future applications in optical communications and high-dimensional quantum key distribution (QKD) systems. An outstanding challenge to the widespread uptake of the OAM resource is its efficient generation. In this work we design a new device that can directly emit an OAM-carrying light beam from a low-cost semiconductor laser. By fabricating micro-scale spiral phase plates within the aperture of a vertical-cavity surface-emitting laser (VCSEL), the linearly polarized Gaussian beam emitted by the VCSEL is converted into a beam carrying specific OAM modes and their superposition states, with high efficiency and high beam quality. This new approach to OAM generation may be particularly useful in the field of OAM-based optical and quantum communications, especially for short-reach data interconnects and QKD
Unlocking the Promise of Systemic Sting Agonist for Cancer Immunotherapy
Stimulator of interferon genes (STING) pathway is the key innate immune pathway involving in cancer immunity. Emerging new molecules and drug delivery systems have made systemic STING agonist immunotherapy possible and demonstrated efficient tumor eradication in preclinical studies. In this perspective, we will discuss the potential mechanisms of STING agonism as a multifaceted anti-cancer therapy and the pharmacological challenges associated with systemic delivery of STING agonists on the level of organs, tissues, cells, and intracellular compartments. We will present and discuss drug delivery strategies to address these challenges. New advances in the field can unlock the promise of systemic STING agonist as effective and safe cancer immunotherapy
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