Abstract: An aerosol delivery device comprises: an aerosol generator portion configured to receive a first aerosol precursor; an air flow passage configured to direct air past the aerosol generator portion to pick up the first aerosol precursor from the aerosol generator portion to form a first aerosol; and a support for maintaining the aerosol generator portion in a substantially central position in the air flow passage.

Abstract: There is herein disclosed a method of communication between a client pair, the client pair including an upstream client and a downstream client, the method being performed over a first optical fiber in an optical fiber pair and including: transmitting a downstream DWDM signal over the first optical fiber, wherein the downstream DWDM signal has a first frequency and contains first data originating from the upstream client, transmitting an upstream DWDM signal over the first optical fiber, wherein the upstream DWDM signal has a second frequency and contains second data originating from the downstream client, wherein the first frequency is different to the second frequency, and performing Quantum Key Distribution over the second optical fiber of the optical fiber pair.

Abstract: There is disclosed an aerosol delivery device. The aerosol delivery device includes a first aerosol first aerosol sized for pulmonary penetration; and a second aerosol sized to inhibit pulmonary penetration. The second aerosol is transmissible within at least one of: a mammalian oral cavity and a mammalian nasal cavity, and the second aerosol comprising an active component for activating at least one of: one or more taste receptors in said oral cavity and one or more olfactory receptors in said nasal cavity. The second aerosol generator includes a Venturi aperture to generate the second aerosol. There is disclosed a consumable for a substitute smoking device and a substitute smoking system. The consumable includes an airflow passage between an upstream inlet of the consumable and a downstream outlet of the consumable. The consumable also includes a porous member for passive aerosol generation. The airflow passage is constricted by the porous member to form a narrowed portion of the airflow passage.

Abstract: A method of performing Quantum Key Distribution can include quantum transmission in a first basis state and in a second basis state being non-orthogonal to the first basis state, from a quantum transmission apparatus to a quantum receiving apparatus over two pairs of optical channels, wherein transmitting in the first basis state includes, at a first time slot, transmitting a photon over a first channel of the first pair and transmitting no photon over a second channel of the first pair, and, at a subsequent time slot, transmitting a photon over the first channel of the first pair, and transmitting a photon over the second channel of the first pair, wherein transmission in the second basis state includes transmitting a first portion of a probability distribution of a photon from the quantum transmission apparatus to the quantum receiving apparatus; and transmitting a second portion of a probability distribution of the photon from the quantum transmission apparatus to the quantum receiving apparatus.

Abstract: A liquid composition comprising a polymer having pendant groups of the formula I: (I) Wherein X is either a bond or is a linking group having 1 to 8 carbons and optionally 1 to 4 heteroatoms selected from O, N and S; and n is 1 to 4.

Abstract: An aerosol delivery device comprises: a storage for storing an aerosol precursor; an aerosol generator comprising an aerosol generator portion configured to receive the aerosol precursor from the storage; an air flow passage configured to direct air past the aerosol generator portion to pick up the aerosol precursor from the aerosol generator portion to form an aerosol; and a barrier arrangement for inhibiting evaporation of aerosol precursor when the barrier arrangement is closed, the barrier arrangement being openable to permit generation of aerosol.

Abstract: There is disclosed an aerosol delivery device. The aerosol delivery device includes a first aerosol first aerosol sized for pulmonary penetration; and a second aerosol sized to inhibit pulmonary penetration. The second aerosol is transmissible within at least one of: a mammalian oral cavity and a mammalian nasal cavity, and the second aerosol comprising an active component for activating at least one of: one or more taste receptors in said oral cavity and one or more olfactory receptors in said nasal cavity. The second aerosol generator includes a Venturi aperture to generate the second aerosol. There is disclosed a consumable for a substitute smoking device and a substitute smoking system. The consumable includes an airflow passage between an upstream inlet of the consumable and a downstream outlet of the consumable. The consumable also includes a porous member for passive aerosol generation. The airflow passage is constricted by the porous member to form a narrowed portion of the airflow passage.

Abstract: A method of transmitting precoded signals can include precoding an optical signal to produce a precoded optical signal, transmitting a precoded optical signal over an optical portion of a first transmission channel, converting the precoded optical signal to a first MIMO signal, transmitting the first MIMO signal over a wireless portion of the first transmission channel, transmitting the precoded optical signal over an optical portion of a second transmission channel, converting the precoded optical signal to a second MIMO signal; transmitting the second MIMO signal over a wireless portion of the second transmission channel; wherein the precoding takes account of both first channel state information associated with the first transmission channel and second channel state information associated with the second transmission channel.

Abstract: There is herein provided a method of performing Quantum Key Distribution, the method including transmitting, in a first basis state, a first photon from a quantum transmitter to a quantum receiver; transmitting, in a second basis state, a second photon from the quantum transmitter to the quantum receiver, the second basis state being non-orthogonal to the first basis state and the transmitter and receiver being optically connected by both a first optical channel and a second optical channel, wherein transmitting the first photon from the quantum transmitter to the quantum receiver in the first basis state comprises: transmitting the first photon from the quantum transmitter to the quantum receiver along either the first optical channel or the second optical channel, wherein transmitting the second photon from the quantum transmitter to the quantum receiver in the second basis state comprises: transmitting a first portion of the probability distribution of the second photon from the transmitter to the receiver

Abstract: A method of configuring an optical network comprising a switching system, a first node, a second node, and an optical link between the first node and the second node. The optical link includes a first optical connection and a second optical connection. The method includes changing a state of the switching system from a first state to a second state. In the first state, the optical network is configured to use the first and second optical connection to transmit first and second optical signals in first and second directions, respectively. In the second state the optical network is configured to use the second and first optical connections to transmit the first and second optical signals in the first and second directions, respectively.

Abstract: There is herein disclosed a computer-implemented method of optimizing optimising a QKD system, the QKD system being adapted to perform a QKD session that involves the propagation of a plurality of photons from a first device to a second device, one of the first and second devices being located aboard a satellite in orbit, the method including running a machine learning algorithm, inputs of the machine learning algorithm comprising one or more values of one or more of the following factors: atmospheric conditions in the vicinity of a path from the first device to the second device; a spatial separation of the first device and the second device; and a measure of the performance of the first and/or the second device, wherein the output of the algorithm is an estimate of the rate at which the first device and the second device generate bits of a quantum key.

Abstract: There is herein provided a method of performing Quantum Key Distribution, the method comprising, transmitting, in a first basis state, a first photon from a quantum transmitter to a quantum receiver; transmitting, in a second basis state, a second photon from the quantum transmitter to the quantum receiver, the second basis state being non-orthogonal to the first basis state and the transmitter and receiver being optically connected by both a first optical channel and a second optical channel, wherein the step of transmitting the first photon from the quantum transmitter to the quantum receiver in the first basis state comprises: transmitting the first photon from the quantum transmitter to the quantum receiver along either the first optical channel or the second optical channel, wherein the step of transmitting the second photon from the quantum transmitter to the quantum receiver in the second basis state comprises: transmitting a first portion of the probability distribution of the second photon from the t

Abstract: There is herein disclosed a method of communication between a client pair, the client pair including an upstream client and a downstream client, the method being performed over a first optical fiber in an optical fiber pair and including: transmitting a downstream DWDM signal over the first optical fiber, wherein the downstream DWDM signal has a first frequency and contains first data originating from the upstream client, transmitting an upstream DWDM signal over the first optical fiber, wherein the upstream DWDM signal has a second frequency and contains second data originating from the downstream client, wherein the first frequency is different to the second frequency, and performing Quantum Key Distribution over the second optical fiber of the optical fiber pair.

Abstract: There is herein disclosed a method of performing Quantum Key Distribution for generating a shared secret key, the method including, at a first node, preparing or measuring a plurality of non-orthogonal quantum states, each of the plurality of non-orthogonal quantum states being prepared or measured using a respective one of a first set of basis states, and, at a second node, preparing or measuring the plurality of non-orthogonal quantum states each, of the plurality of non-orthogonal quantum states being prepared or measured using a respective one of a second set of basis states, and, at a third node, obtaining an indication of the first set of basis states from the first node and performing a key agreement stage with a fourth node to agree the shared secret key, the key agreement stage involving the first and second sets of basis states.

Abstract: There is herein disclosed a system for performing Quantum Key Distribution, the system including a transmitter adapted to transmit a plurality of optical pulses, a first receiver, a second receiver, an optical switch with an input which is in optical communication with the transmitter, the switch being switchable between a first switching position in which the input is optically connected to the first receiver, and a second switching position in which the input is optically connected to the second receiver, the system further including a guide for guiding a portion of the plurality of optical pulses to the first receiver via an optical path that bypasses the optical switch.

Abstract: A system of transmitting optical pulses from a transmitter to first and second receivers for the purposes of quantum key distribution is disclosed. The system can include a transmitter configured to transmit a plurality of optical pulses; first and second receivers configured to receive some or all of the plurality of optical pulses; a guide for guiding the plurality of optical pulses, the guide having first and second output ports, the first output port being in optical communication with the first receiver and the second output port being in optical communication with the second receiver, the guide being configured to output a proportion of the optical pulses at the first output port and a proportion of the optical pulses at the second output port, modification means for modifying the guide so as to change the proportion of the optical pulses output at the first output port.

Abstract: An optical data transmission system and method for, at an optical transmitter, converting to a second wavelength, an optical data signal at a first wavelength; transmitting at the second wavelength, the optical data signal to an optical receiver over an optical path; and transmitting at the first wavelength, to the receiver over the path a single-photon signal comprising a stream of single photons. The optical path is configured to carry optical signals at different wavelengths and the optical path attenuates signals at the first wavelength less than the optical path attenuates signals at the second wavelength. The optical data transmission system and method for, at the receiver, receiving the single-photon signal at the first wavelength and receiving the optical data signal at the second wavelength; and converting the optical data signal to the first wavelength for detection.

Abstract: A method for operating a communications network node, the node including a first amplified optical section, a second non-optical section, and an optical bypass section the method including receiving at the node, a first optical channel at a first wavelength and a second optical channel at a second wavelength; directing the first optical channel to the first amplified optical section; directing the second optical channel to the second non-optical section during a first time period; and directing the second optical channel to the optical bypass section during a second time period.

Abstract: A method for operating a communications network node, the node including a first amplified optical section, a second non-optical section, and an optical bypass section the method including receiving at the node, a first optical channel at a first wavelength and a second optical channel at a second wavelength; directing the first optical channel to the first amplified optical section; directing the second optical channel to the second non-optical section during a first time period; and directing the second optical channel to the optical bypass section during a second time period.

Abstract: An optical data transmission system and method for, at an optical transmitter, converting to a second wavelength, an optical data signal at a first wavelength; transmitting at the second wavelength, the optical data signal to an optical receiver over an optical path; and transmitting at the first wavelength, to the receiver over the path a single-photon signal comprising a stream of single photons. The optical path is configured to carry optical signals at different wavelengths and the optical path attenuates signals at the first wavelength less than the optical path attenuates signals at the second wavelength. The optical data transmission system and method for, at the receiver, receiving the single-photon signal at the first wavelength and receiving the optical data signal at the second wavelength; and converting the optical data signal to the first wavelength for detection.