Abstract: A computer-implemented method for use in decoding syndromes of a quantum error correction code, the syndromes comprising measurement data from a quantum computer comprising a plurality of syndrome qubits and a plurality of data qubits.

Abstract: A decoder apparatus for decoding syndromes of a quantum error correction code, the syndromes comprising measurement data from a quantum computer, the quantum computer comprising an array of qubits including syndrome qubits and data qubits. The decoder apparatus is configured to: receive syndrome index data representative of: a physical location of each of the array of qubits within the quantum computer; and lattice dimensions of the array of qubits; receive the syndromes of the quantum error correction code from the quantum computer; determine physical co-ordinate positions for each of the array of qubits based on the syndrome index data; decode the syndromes of the quantum error correction code using the determined physical co-ordinate positions.

Abstract: A computer-implemented postselection-free method of initializing qubits in a quantum computer, comprising: preparing at least one data qubit and a plurality of auxiliary qubits in respective initial states, wherein each of the at least one data qubit and the plurality of auxiliary qubits has a respective probability of being prepared with an error; and, performing a plurality of non-measurement multi-qubit quantum logic operations that propagate errors between the at least one data qubit and the plurality of auxiliary qubits so as to reduce the probability of an error affecting the at least one data qubit.

Abstract: An apparatus for a quantum computer comprising a memory device and a converter block, the memory device comprising: a local command module; and a double-buffer-memory module comprising a plurality of pairs of memory modules, each memory module: coupled to the local command module; and configured to store a respective operation for controlling a qubit of the quantum computer; wherein the local command module is configured to: receive an instruction to provide the operation for the qubit; read the operation from a respective one of the plurality of pairs of memory modules indicated by the instruction; and provide the operation to the converter block; wherein the converter block is configured to receive the operation from the memory device and provide digital output pulses, representative of the operation, to an output interface, the output interface configured to provide the digital output pulses to a digital-to-analogue converter for controlling the qubit to perform the operation.

Abstract: A computer-implemented method of selecting a power-optimal compression scheme for transmitting digital control signals from a classical interface of a quantum computer to a quantum processing unit (QPU) of the quantum computer is disclosed. The method involves receiving static and dynamic power consumption values associated with operations performable by the QPU; determining compression schemes implementable by the QPU; calculating total power consumption values associated with receiving and decompressing a representative control signal at the QPU using the compression schemes; and selecting the compression scheme having the lowest total power consumption value. A corresponding method for transmitting control signals from a classical interface of the quantum computer to the QPU is also disclosed in which a compressed control signal is transmitted from the classical interface to the QPU with one or more delays.

Abstract: A computer-implemented method for determining a measurement value for each operator of a plurality of operators. The method comprises grouping the plurality of operators into one or more sets of mutually commuting operators, each set comprising one or more of the plurality of operators. Determining, for each set of operators: a subset of transformed operators based on the set of operators, such that the set of operators are equal to products of the subset of transformed operators; a mapping circuit based on the subset of transformed operators, wherein the mapping circuit comprises an arrangement of quantum gates configured to operate on a plurality of qubits in a quantum computer.

Abstract: An apparatus can be configured to control a quantum memory of a quantum computer. The quantum memory can have a first qubit. The apparatus can comprise: a first-classical-register; a first-clock; a first-machine-language-buffer, that stores a first-machine-language-circuit; and a first-implementer. The first-machine-language-circuit includes: a first-timestamp; a first-qubit-identifier unique to the first qubit; a first-qubit-control-instruction; and a first-protected-location of the first-classical-register. The first-implementer can be configured to: read the first-machine-language-circuit from the first-machine-language-buffer; and read a first-control-value from the first-protected-location of the first-classical-register, the first-control-value can be configured to encode either a first-execute-instruction or a first-alternate-control-instruction.

Abstract: An apparatus can be configured to control a quantum memory of a quantum computer. The quantum memory can have a first qubit. The apparatus can comprise: a first-classical-register; a first-clock; a first-machine-language-buffer, that stores a first-machine-language-circuit; and a first-implementer. The first-machine-language-circuit includes: a first-timestamp; a first-qubit-identifier unique to the first qubit; a first-qubit-control-instruction; and a first-protected-location of the first-classical-register. The first-implementer can be configured to: read the first-machine-language-circuit from the first-machine-language-buffer; and read a first-control-value from the first-protected-location of the first-classical-register, the first-control-value can be configured to encode either a first-execute-instruction or a first-alternate-control-instruction.

Abstract: A computing system can be configured to execute a classical-quantum hybrid algorithm. The computing system may comprise a classical computer comprising one or more classically-executable-nodes of the classical-quantum hybrid algorithm; and a quantum computer comprising a quantum-processor-unit. The quantum computer is operatively coupled to the classical computer. The one or more classically-executable-nodes may be configured to send a first-circuit and a second-circuit to the quantum computer for evaluation. The quantum computer may be configured to: receive the first-circuit and the second-circuit; evaluate the first-circuit, using the quantum-processor-unit, to determine a first-circuit-evaluation; and send the first-circuit-evaluation to the classical computer. The one or more classically-executable-nodes may be configured to: receive the first-circuit-evaluation; and process the first-circuit-evaluation during a first-time-interval.

Abstract: A computing system can be configured to determine a compressed quantum circuit architecture, for a quantum computer, based on a point-symmetry group of a physical system. The computing system can comprise a classical computer operatively coupled to the quantum computer. The classical computer can be configured to transmit a symmetrized-unitary operator to the quantum computer to enable configuration of the compressed quantum circuit architecture and application of the compressed quantum circuit architecture to a quantum memory containing a first quantum basis state of the physical system stored in a plurality of qubits. The first quantum basis state transforms according to a first irreducible representation of the point-symmetry group.

Abstract: A modular barrier system enables demountable outdoor rinks—typically for ice hockey, or ice skating, or street hockey. A rink includes multiple panels, each having a factory-attached link. These panels are linearly disposed, adjacent to one another, to form a piecewise continuous boundary wall enclosing a desired area. Attaching one link to the next, typically via insertion of a thumbscrew, connects the panels into a robust assembly. Both straight and curved panels are provided, thereby enabling a rink with round corners. Each panel includes a shell molded from plastic resin, and has a hollow interior which can be filled with water (or other ballast).

Abstract: A high performance, yet low cost, modular barrier system enables demountable outdoor rinks—typically for ice hockey, or ice skating, or street hockey—that are robust and convenient to install. A rink includes multiple panels, each having a factory-attached link. These panels are linearly disposed, adjacent to one another, to form a piecewise continuous boundary wall enclosing a desired area. Attaching one link to the next, typically via insertion of a thumbscrew, connects the panels into a robust assembly. Both straight and curved panels are provided, thereby enabling a rink with round corners. Each panel includes a shell molded from plastic resin, and has a hollow interior which can be filled with water (or other ballast).

Abstract: A portable ice rink includes a wall formed of multiple wall members linearly disposed adjacent to one another to form a piecewise continuous wall that encloses a desired area, and also includes a chain of links disposed on the outside of the wall members for reinforcement. The rink may further include a waterproof tarp extending underneath the wall members and folded upwards along the outer side of the wall, with its edge tied to the change of links. The tarp can contain water which then freezes to form a skating surface. Curved wall members are provided to form a rink with round corners. Each wall member is a discrete unit, made of molded plastic, and having a hollow interior which can be filled with water (or other ballast). Each wall member is designed with stiffening features to maintain the flatness of its inner surface after filling.

Abstract: A portable ice rink includes a wall formed of multiple wall members linearly disposed adjacent to one another to form a piecewise continuous wall that encloses a desired area, and also includes a chain of links disposed on the outside of the wall members for reinforcement. The rink may further include a waterproof tarp extending underneath the wall members and folded upwards along the outer side of the wall, with its edge tied to the change of links. The tarp can contain water which then freezes to form a skating surface. Curved wall members are provided to form a rink with round corners. Each wall member is a discrete unit, made of molded plastic, and having a hollow interior which can be filled with water (or other ballast). Each wall member is designed with stiffening features to maintain the flatness of its inner surface after filling.

Abstract: A detachable lens for variable focus spectacles, the lens including a plurality of magnets in a groove on its rear surface for holding the lens to the spectacles. An interlocking boss keeps the lens from sliding off the spectacles, and a locating tab provides a means for assuring that the lens is installed on the correct side of the spectacles and with the proper orientation.

Abstract: Variable focus spectacles which comprise i) a focus module that includes two variable focus lens sections, said sections each including a first fixed plastic lens and an adjustable focus liquid lens, and ii) a second fixed plastic lens that preferably includes most or all of the optical power needed by the intended wearer to correct his/her distance vision. The second fixed plastic lens is preferably attached to the focus module by magnetic attraction.

Abstract: An actuating mechanism for spectacles which include two variable focus lens units. The mechanism mounts on the spectacle bridge; and includes two elongated drive levers mounted near opposite ends of the bridge, each extending toward the other end of the bridge. The free end of each driving lever is connected to its corresponding lens unit through a linkage. The driving levers are caused to rotate simultaneously, but in opposite directions, by a cam that is driven by a sliding member that slides along the bridge. By positioning the sliding member as desired, the spectacles wearer causes the cam to rotate, thereby causing the driving levers to rotate, and both lens units to change focal length.

Abstract: An actuating mechanism for spectacles which include two variable focal length lens units. Each lens unit is fitted with a coupling member which extends from the lens unit into the bridge of the spectacles. A linearly-movable finger-operated slider, having a finger pad extending above the bridge, causes a cam within the bridge to rotate as it is moved, the cam being coupled to the coupling members causing them to move and the focal length of the lens units thereby to change.

Abstract: A liquid-filled variable focal length lens of the type which has a distensible membrane as one of the lens surfaces, and a membrane support member to support the perimeter of the free area of the membrane. By using a membrane support member having a toroidally shaped portion, the membrane is supported such that it has a circular free area irrespective of the shape of the perimeter of the lens. The cross sectional shape of the toroidal portion of the support member is preferably approximately an arc of a circle, and the perimeter of the free area of the membrane is maintained tangent thereto.

Abstract: A sliderless shuttle and wire guide assembly for toroidal coil winding machines provides unusually compact storage for winding wire or tape carried by the shuttle. The novel cross-sectional configuration of the shuttle permits winding of extremely small toroidal cores. An adjustable and retractable wire guide assembly permits the use of different size shuttles for wire or insulating tape having a wide range of sizes, while also providing valuable protection against escaping coils of broken wire or the release of a "flying" empty shuttle from the coil winding machine.