Aspects of the subject disclosure may include, for example, identifying a request to facilitate communications between first and second processing nodes, determining that the communications are to be established via quantum teleportation between, and identifying a network path comprising a first path segment to obtain a quantum channel, wherein quantum entanglement is established between the first and second processing nodes based on transportation of a first quantum entangled object via the quantum channel. A classical communication channel is facilitated between the first and second processing nodes, adapted to exchange between the nodes, quantum state information of a measurement performed upon the first quantum entangled object. Information is exchanged between the first and second processing nodes via the quantum channel according to the transported first quantum entangled object and the exchanged quantum state information. Other embodiments are disclosed.

An example operation may include one or more of setting, by a first node, a cut-off time for a resolution of an update to a service contract received from at least one node of a plurality of second nodes over a blockchain, acquiring, by the first node, resolution parameters from a blockchain ledger, and executing a smart contract to resolve the service contract based on the update to the service contract and the resolution parameters.

The invention relates to a QKD System Active combiner (200) adapted to be installed in a QKD apparatus, said QKD apparatus comprising an emitter (100), a receiver (110) and QKD systems (102/112), wherein the emitter (100) is adapted to send communication signals to the receiver (110) through the QKD System Active combiner (200), characterized in that the QKD System Active combiner (200) comprises an active attenuation system comprising a processing unit (230) adapted to automatically control at least one variable optical attenuator (150) through a control channel (290) in order to control an attenuation of a signal to be sent to the receiver, and a detector/monitor (240) adapted to monitor the intensity of the signal downstream the attenuation, and wherein the processing unit is adapted to control the variable optical attenuator (150) based on a QBER information or an intensity of a signal received by the receiver, sent by the QKD systems (112) through a classical channel (250).

Quantum network devices, systems, and methods are provided to enable long-distance transmission of quantum bits (qubits) for applications such as Quantum Key Distribution (QKD), entanglement distribution, and other quantum communication applications. Such systems and methods provide for separately storing first, second, third, and fourth photons, wherein the first and second photons and the third and fourth photons are respective first and second entangled photon pairs, triggering a synchronized retrieval of the stored first, second, third, and fourth photons such that the first photon is propagated to a first node, the second and third photons are propagated to a second node, and the fourth photon is propagated to a third node, and creating a new entangled pair comprising the first and fourth photons at the first and third nodes to transmit quantum information.

A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The receiver node may be configured to arrange a received bit stream of optical pulses from the transmitter node into time bins, convert the optical pulses in the time bins into corresponding optical pulses in frequency bins, and detect respective optical pulse values from each of the frequency bins.

Methods, systems, and devices for quantum key distribution (QKD) in passive optical networks (PONs) are described. A PON may be a point-to-multipoint system and may include a central node in communication with multiple remote nodes. In some cases, each remote node may include a QKD transmitter configured to generate a quantum pulse indicating a quantum key, a synchronization pulse generator configured to generate a timing indication of the quantum pulse, and filter configured to output the quantum pulse and the timing indication to the central node via an optical component (e.g., an optical splitter, a cyclic arrayed waveguide grating (AWG) router). The central node may receive the timing indications and quantum pulses from multiple remote nodes. Thus, the central node and remote nodes may be configured to communicate data encrypted using quantum keys.

Methods, systems, and devices for quantum key distribution (QKD) in passive optical networks (PONs) are described. A PON may be a point-to-multipoint system and may include a central node in communication with multiple remote nodes. In some cases, each remote node may include a QKD transmitter configured to generate a quantum pulse indicating a quantum key, a synchronization pulse generator configured to generate a timing indication of the quantum pulse, and filter configured to output the quantum pulse and the timing indication to the central node via an optical component (e.g., an optical splitter, a cyclic arrayed waveguide grating (AWG) router). The central node may receive the timing indications and quantum pulses from multiple remote nodes. Thus, the central node and remote nodes may be configured to communicate data encrypted using quantum keys.

A system for quantum key synchronization within a server-cluster is provided. The system may include a plurality of silicon-based servers encapsulated in quantum cases. Each quantum case may include a quantum tunneling transmitter module, a quantum random number generator and a quantum entanglement module. The quantum cases may communicate with each other via the quantum tunneling transmitter module or any other suitable manner. The quantum cases may only communicate with cases with which they are entangled. Therefore, in the event of a compromise on one of the servers, the quantum entanglement module, included in the case that encapsulates the compromised server, may become disentangled, and therefore not be able to communicate with the other servers included in the cluster using an internal communications protocol.

There is herein provided a method of determining whether one or more pairs of qubits are quantum-entangled, the method comprising: performing a Bell State measurement on a first qubit, the first qubit being from a first multi-partite quantum-entangled state and a second qubit, the second qubit being from a second multi-partite quantum-entangled state, performing a Bell Inequality test on a third qubit, the third qubit being from the first multipartite quantum-entangled state and a fourth qubit, the fourth qubit being from the second quantum-entangled state, determining, using an outcome of the Bell Inequality test, whether a fifth qubit, the fifth qubit being from the first multipartite quantum-entangled state is quantum-entangled with a sixth qubit, the sixth qubit being from the second multi-partite quantum-entangled state.

Described is a method of setting up a plurality of quantum communications links, forming a quantum network providing provably secure communications and internet services over intercontinental distances without requiring direct line of sight communication or the intermediate use of the entanglement resource of satellites. Also described is a quantum communicator device for use in this method. Two or more quantum memory units are disposed at a first location, an entangled link is set up between at least two of the quantum memory units, at least one of the quantum memory units sharing in the entangled link is physically transported to a second location. The quantum communicator device comprises communications nodes, an optical interface to set up entanglement to other devices and storage nodes, each node in the form of a quantum memory unit capable of storing quantum information for a desired length of time, i.e. weeks or longer.