593 results about "Qubit" patented technology

An analog processor, for example a quantum processor may include a plurality of elongated qubits that are disposed with respect to one another such that each qubit may selectively be directly coupled to each of the other qubits via a single coupling device. Such may provide a fully interconnected topology.

A method for computing using a quantum system comprising a plurality of superconducting qubits is provided. Quantum system can be in any one of at least two configurations including (i) an initialization Hamiltonian H₀ and (ii) a problem Hamiltonian H_P. The plurality of superconducting qubits are arranged with respect to one another, with a predetermined number of couplings between respective pairs of superconducting qubits in the plurality of qubits, such that the plurality of superconducting qubits, coupled by the predetermined number of couplings, collectively define a computational problem to be solved. In the method, quantum system is initialized to the initialization Hamiltonian H_O. Quantum system is then adiabatically changed until it is described by the ground state of the problem Hamiltonian H_P. The quantum state of quantum system is then readout thereby solving the computational problem to be solved.

A method for quantum computing using a quantum system comprising a plurality of qubits is provided. The system can be in any one of at least two configurations at any given time including one characterized by an initialization Hamiltonian H₀ and one characterized by a problem Hamiltonian H_P. The problem Hamiltonian H_P has a final state. Each respective first qubit in the qubits is arranged with respect to a respective second qubit in the qubits such that they define a predetermined coupling strength. The predetermined coupling strengths between the qubits in the plurality of qubits collectively define a computational problem to be solved. In the method, the system is initialized to H₀ and is then adiabatically changed until the system is described by the final state of the problem Hamiltonian H_P. Then the state of the system is read out by probing an observable of the σ_X Pauli matrix operator.

A coupling system may include an rf-SQUID having a loop of superconducting material interrupted by a compound Josephson junction; and a first magnetic flux inductor configured to selectively provide a mutual inductance coupling the first magnetic flux inductor to the compound Josephson junction, wherein the loop of superconducting material positioned with respect to a first and second qubits to provide respective mutual inductance coupling therebetween. The coupling system may further include a second magnetic flux inductor configured to selectively provide a second magnetic flux inductor mutual inductance coupling the second magnetic flux inductor to the compound Josephson junction. A superconducting processor may include the coupling system and two or more qubits. A method may include providing the first, the second and the third mutual inductances.

An electro-optical system for exchanging quantum information between optical qubits and including a superconductive microwave cavity; an electro-optical material: a superconductive qubit circuit formed on the electro-optical material including a superconductive qubit; a dipole antenna, formed on the electro-optical material for directly coupling the superconductive qubit to the superconductive microwave cavity; an optical input for receiving input optical photons; a microwave input for receiving input microwave photons; and an optical output for outputting modulated optical photons, wherein a frequency and a phase of the optical photon is modulated with a state of the superconducting qubit by the dipole antenna.

A superconducting readout system includes a computation qubit; a measurement device to measure a state of the computation qubit; and a latch qubit that mediates communicative coupling between the computation qubit and the measurement device. The latch qubit includes a qubit loop that includes at least two superconducting inductors coupled in series with each other; a compound Josephson junction that interrupts the qubit loop that includes at least two Josephson junctions coupled in series with each other in the compound Josephson junction and coupled in parallel with each other with respect to the qubit loop; and a first clock signal input structure to couple clock signals to the compound Josephson junction.

A method and system to support secure booting and configuration. The mechanism employs an optical link comprising a quantum channel that is used to send data encoded as quantum bits (qubits) via respective photons. Qubits encoded using a first random basis at the client and are sent to the boot server, which processes the qubits using a second random basis to extract the encoded data. A public channel is used to send data indicative of the second random basis to the client. A symmetric quantum key is then derived a both the client and the boot server using a comparison of the random basis' and the original and extracted data. The scheme enables the presence of an eavesdropper to be detected on the quantum channel. A DHCP message exchange is employed to obtain a network address, and, optionally, be provided with a network address for one or more boot servers. A boot image request is made to the boot server by the client, and a subsequent boot image is downloaded via a secure channel facilitated by the symmetric quantum key.

A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

A first qubit having a superconducting loop interrupted by a plurality of Josephson junctions is provided. Each junction interrupts a different portion of the superconducting loop and each different adjacent pair of junctions in the plurality of Josephson junctions defines a different island. An ancillary device is coupled to the first qubit. In a first example, the ancillary device is a readout mechanism respectively capacitively coupled to a first and second island in the plurality of islands of the first qubit by a first and second capacitance. Quantum nondemolition measurement of the first qubit's state may be performed. In a second example, the ancillary device is a second qubit. The second qubit's first and second islands are respectively capacitively coupled to the first and second islands of the first qubit by a capacitance. In this second example, the coupling is diagonal in the physical basis of the qubits.

A superconducting flux digital-to-analog converter includes a superconducting inductor ladder circuit. The ladder circuit includes a plurality of closed superconducting current paths that each includes at least two superconducting inductors coupled in series to form a respective superconducting loop, successively adjacent or neighboring superconducting loops are connected in parallel with each other and share at least one of the superconducting inductors to form a flux divider network. A data signal input structure provides a respective bit of a multiple bit signal to each of the superconducting loops. The data signal input structure may include a set of superconducting quantum interference devices (SQUIDs). The data signal input structure may include a superconducting shift register, for example a single-flux quantum (SFQ) shift register or a flux-based superconducting shift register comprising a number of latching qubits.

Various embodiments provide a coupling mechanism, method of activation and a square lattice. The coupling mechanism comprises two qubits and a tunable coupling qubit that activates an interaction between the two qubits by modulation of a frequency of the tunable coupling qubit. The tunable coupling qubit capacitively couples the two qubits. The tunable coupling qubit is modulated at a difference frequency of the two qubits. The difference frequency may be significantly larger than an anharmonicity of the two qubits. The tunable coupling qubit may be coupled to the two qubits by two electrodes separated by a superconducting quantum interference device (SQUID) loop having two Josephson junctions or by a single electrode with a SQUID loop coupling to ground. The SQUID loop is controlled by an inductively-coupled flux bias line positioned at the center of the tunable coupling qubit.

A superconducting structure that can operate, for example, as a qubit or a superconducting switch is presented. The structure includes a loop formed from two parts. A first part includes two superconducting materials separated by a junction. The junction can, for example, be a 45° grain boundary junction. The second part can couple the two superconducting materials across the junction. The second part includes a superconducting material coupled to each of the two superconducting materials of the first part through c-axis junctions. Further embodiments of the invention can be as a coherent unconventional superconducting switch, or a variable phase shift unconventional superconductor junction device.

A coupling system to couple a first and a second qubit in response to a state of the coupling system that may be set by two input signals.

Quantum information processing apparatus and methods are described. The apparatus comprises a device for defining a qubit and a reflectometry circuit for reading out a state of the qubit. The device comprises a semiconductor nanowire extending along a first direction having first and second obtuse or acute edges running along the first direction, gate dielectric overlying the first and second edges of the nanowire and a split gate running across a section of the nanowire in a second, transverse direction, the split gate comprising first and second gates overlying the first and second edges respectively. The reflectometry circuit comprises a resonator coupled to the first or second gate.

A superconducting quantum-bit device based on Josephson junction has a charge as a first principal degree of freedom assigned to writing and a phase as a second principal degree of freedom assigned to reading. The device comprises a Cooper-pair box comprising first and second Josephson junctions defining a charge island of the Cooper-pair box closing up onto a superconducting loop. A read circuit comprises a read Josephson junction JL inserted into the superconducting loop and having a Josephson energy Ej at least 50 times greater than the Josephson energy of each of the first and second Josephson junctions.

The present disclosure provides a quantum processor realised in a semiconductor material and method to operate the quantum processor to implement error corrected quantum computation. The quantum processor comprises a plurality of qubit elements disposed in a two-dimensional matrix arrangement. The qubits are implemented using the nuclear or electron spin of phosphorus donor atoms. Further, the processor comprises a control structure with a plurality of control members, each arranged to control a plurality of qubits disposed along a line or a column of the matrix. The control structure is controllable to perform topological quantum error corrected computation.

A qubit generating unit 40 generates a qubit having a predetermined quantum state. A qubit encoding unit 70 performs quantum encoding of the generated qubit. A first pseudo-random number generating unit 60 generates a first pseudo-random number from secretly shared information 3 which has been secretly shared with the quantum receiving device 200 in advance. A quantum modulator 80 performs quantum modulation of the qubit on which quantum encoding has been performed based on the first pseudo-random number and sends the modulated qubit to the quantum receiving device 200. A second pseudo-random number generating unit 220 generates a second pseudo-random number from secretly shared information 21 which has been secretly shared with the above quantum sending device 100 in advance synchronously with generation of the above first pseudo-random number. A qubit demodulator 230 performs quantum demodulation of the qubit which has been received from the quantum demodulator 80 based on the second pseudo-random number.