55 results about "Superconducting loop" patented technology

A quantum computing structure comprising a superconducting phase-charge qubit, wherein the superconducting phase-charge qubit comprises a superconducting loop with at least one Josephson junction. The quantum computing structure also comprises a first mechanism for controlling a charge of the superconducting phase-charge qubit and a second mechanism for detecting a charge of the superconducting phase-charge qubit, wherein the first mechanism and the second mechanism are each capacitively connected to the superconducting phase-charge qubit.

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.

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.

A superconducting circuit includes a first transformer to produce a first alternating-current output at a secondary-side inductor, a second transformer to produce a second alternating-current output at a secondary-side inductor, a first pulse generating circuit to produce a single flux quantum pulse responsive to the first alternating-current output, a second pulse generating circuit to produce a single flux quantum pulse responsive to the second alternating-current output, and a confluence buffer circuit to merge the single flux quantum pulses from the pulse generating circuits, wherein each of the pulse generating circuits includes a superconducting loop including the secondary-side inductor, a first Josephson junction situated in the superconducting loop to generate the single flux quantum pulse, and a second Josephson junction situated in the superconducting loop, a threshold value of the second Josephson junction for an electric current flowing through the secondary-side inductor being different from that of the first Josephson junction.

A solid-state quantum computing qubit includes a multi-terminal junction coupled to a superconducting loop where the superconducting loop introduces a phase shift to the superconducting order parameter. The ground state of the supercurrent in the superconducting loop and multi-terminal junction is doubly degenerate, with two supercurrent ground states having distinct magnetic moments. These quantum states of the supercurrents in the superconducting loop create qubits for quantum computing. The quantum states can be initialized by applying transport currents to the external leads. Arbitrary single qubit operations may be performed by varying the transport current and/or an externally applied magnetic field. Read-out may be performed using direct measurement of the magnetic moment of the qubit state, or alternatively, radio-frequency single electron transistor electrometers can be used as read-out devices when determining a result of the quantum computing. Further, qubits as described above can form arrays of qubits for performing controlled quantum computing calculations. In one example, an array of qubits can be utilized as a random number generator.

New MRI coil and resonators are disclosed based solely on superconducting inductive element and built-in capacitive elements as well as hybrid superconducting-metal inductive and capacitive elements having superior SNR. Single and multiple small animal MRI imaging units are also disclosed including one or more resonators of this invention surrounding one or more small animal cavities. Methods for making and using the MRI coils and/or arrays are also disclosed.

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 Josephson-coupled resonator amplifier is provided. The Josephson-coupled resonator amplifier includes a first and a second resonator, each formed from respective lumped-element capacitance and respective lumped-element inductance. The Josephson-coupled resonator amplifier further includes one or more Josephson junctions coupling the first resonator to the second resonator, whereby a superconducting loop is formed from at least the lumped-element inductance of the resonators and the one or more Josephson junctions.

A Superconducting Quantum Interference Device (SQUID) is disclosed comprising a pair of resistively shunted Josephson junctions connected in parallel within a superconducting loop and biased by an external direct current (dc) source. The SQUID comprises a semiconductor substrate and at least one superconducting layer. The metal layer(s) are separated by or covered with a semiconductor material layer having the properties of a conductor at room temperature and the properties of an insulator at operating temperatures (generally less than 100 Kelvins). The properties of the semiconductor material layer greatly reduces the risk of electrostatic discharge that can damage the device during normal handling of the device at room temperature, while still providing the insulating properties desired to allow normal functioning of the device at its operating temperature. A method of manufacturing the SQUID device is also disclosed.

A superconducting analog-to-digital converter includes a superconducting input loop to which is applied an analog voltage to be converted to a digital format. The superconducting loop includes two Josephson junctions for converting said analog input voltage into a single flux quantum (SFQ) pulse stream having a frequency f1 which is directly proportional to the amplitude of the analog input voltage. The loop includes two outputs for distributing the pulse stream in a cyclical and staggered fashion onto the two loop outputs such that the frequency of the pulses along each one of the loop outputs is f1/2. Additional frequency divider circuits may be coupled to the loop outputs to produce pulse streams on N output lines having a frequency of f1/N.

A gradiometer integrating pickup coils comprises pickup coils 11Xp, 11Xn magnetically connected to a SQUID through associated input coils 2, and pickup coils 11Yp, 11Yn magnetically connected to a SQUID through associated input coils 2, respectively. Two superconducting loops are connected in series to each of the SQUIDs, when viewed from Josephson junctions 5. The input coils 2 form superconducting closed loops together with the pickup coils 11Xp, 11Xn, 11Yp, 11Yn associated therewith. The SQUIDs are respectively connected to form an 8-figured shape as a whole such that currents flow in two superconducting loops of each SQUID in opposite directions to each other, with respect to the application of a uniform field, in order to reduce environmental magnetic field noise.

The invention provides a superconducting quantum interference device and a preparation method. The superconducting quantum interference device comprises an under-damped SQUID and a series resistor; the under-damped SQUID and the series resistor are connected in series; and the two ends of the under-damped SQUID and the series resistor connected in series are connected with a bias voltage. A firstsuperconducting material layer, a first insulating material layer and a second superconducting material layer are sequentially deposited, and etching is performed to form a superconducting loop and abottom electrode structure; the second superconducting material layer is etched to form a Josephson junction; the second insulating material layer is deposited and etched, and an electrode opening isformed in the top of the Josephson junction; a resistance material layer is deposited and etched to form a bypass resistor and the series resistor; and a top electrode of a third superconducting material layer is deposited and etched. The under-damped SQUID and the resistor are connected in series to form a Series resistance SQUID device; the device works in a voltage bias mode and has the characteristics of being lower in noise and higher in sensitivity; and the preparation process is the same as a common SQUID preparation process, so that the preparation difficulty is not increased.

A superconducting device operable at temperatures in excess of 30° K. and a method for making the device are described. A representative device is an essentially coplanar SQUID device formed in a single layer of high T_c superconducting material, the SQUID device being operable at temperatures in excess of 60° K. High energy beams, for example ion beams, are used to convert selected portions of the high T_c superconductor to nonsuperconductive properties so that the material now has both superconductive regions and nonsuperconductive regions. In this manner a superconducting loop having superconducting weak links can be formed to comprise the SQUID device.