A gravitational radiation communication system. The system includes a gravitational radiation transmitter and a gravitational radiation receiver. Each of the transmitter and the receiver includes a first cylindrical superconducting cavity, having a first length, a first diameter, and an entrance aperture for electromagnetic radiation; a second cylindrical superconducting cavity, having a second length, a second diameter, and a first aperture for gravitational radiation, the second cavity being coaxial with and adjacent the first cavity; and a superconducting movable membrane positioned between the first cavity and the second cavity and configured to provide parametric amplification of electromagnetic fields in the second cavity. The first aperture is configured to pass gravitational radiation.

Examples described in this disclosure relate to superconducting devices, including reciprocal quantum logic (RQL) compatible devices. A superconducting device including at least one superconducting element having a first coefficient of thermal expansion is provided. The at least one superconducting element is formed on a dielectric layer having a second coefficient of thermal expansion and the first coefficient of thermal expansion is different from the second coefficient of thermal expansion causing a strain mismatch between the at least one superconducting element and the dielectric layer when the superconducting device is operating in a cryogenic environment. The superconducting device may also include at least one dummy element configured to lower stress at an interface between the at least one superconducting element and the dielectric layer when the at least one superconducting device is operating in the cryogenic environment.

An electronic device (e.g., a diode) is provided that includes a substrate and a patterned layer of superconducting material disposed over the substrate. The patterned layer forms a first electrode, a second electrode, and a loop coupling the first electrode with the second electrode by a first channel and a second channel. The first channel and the second channel have different minimum widths. The device further includes a magnet that applies a magnetic field to the loop, which produces an expulsion current in the loop that travels toward the second electrode in the first channel and toward the first electrode in the second channel. For a range of current magnitudes, when the magnetic field is applied to the patterned layer of superconducting material, the conductance from the first electrode to the second electrode is greater than the conductance from the second electrode to the first electrode.

A technique relates a superconducting microwave cavity. An array of posts has different heights in the cavity, and the array supports a localized microwave mode. The array of posts includes lower resonant frequency posts and higher resonant frequency posts. The higher resonant frequency posts are arranged around the lower resonant frequency posts. A first plate is opposite a second plate in the cavity. One end of the lower resonant frequency posts is positioned on the second plate so as to be electrically connected to the second plate. Another end of the lower resonant frequency posts in the array is open so as not to form an electrical connection to the first plate. Qubits are connected to the lower resonant frequency posts in the array of posts, such that each of the qubits is physically connected to one or two of the lower resonant frequency posts in the array of posts.

A set of superconducting devices is interconnected in a lattice that is fabricated in a single two-dimensional plane of fabrication such that a superconducting connection can only reach a first superconducting device in the set while remaining in the plane by crossing a component of a second superconducting device that is also located in the plane. A superconducting coupling device having a span and a clearance height is formed in the superconducting connection of the first superconducting device. A section of the superconducting coupling device is separated from the component of the second superconducting device by the clearance in a parallel plane. A potential of a first ground plane on a first side of the component is equalized with a second ground plane on a second side of the component using the superconducting coupling device.

The present invention provides a process and structure of microfabricated air bridges for planar microwave resonator circuits. In an embodiment, the invention includes depositing a superconducting film on a surface of a base material, where the superconducting film is formed with a compressive stress, where the compressive stress is higher than a critical buckling stress of a defined structure, etching an exposed area of the superconducting film, thereby creating the at least one bridge, etching the base material, thereby forming a gap between the at least one bridge and the base material, depositing the at least one metal line on at least part of the superconducting film and at least part of the base material, where the at least one metal line runs under the bridge.

Adaptions and improvements to coaxial metal powder filters include distributing a dissipative matrix mixture comprising superconductive material, metal powder, epoxy, and/or magnetic material within a volume defined by an outer tubular conductor and inner conductor. The frequency response of the filter may be tuned by exploiting the energy gap frequency of superconductive material in the dissipative matrix. The inner surface of the outer tubular conductor may be covered with a superconductive material. For a dissipative matrix comprising magnetic material or superconductive powder particles of a certain size, an external magnetic field can be applied to tune the frequency response of the filter.

A stacked quantum computing device including a first chip that includes a first dielectric substrate and a superconducting qubit on the first dielectric substrate, and a second chip that is bonded to the first chip and includes a second dielectric substrate, a qubit readout element on the second dielectric substrate, a control wire on the second dielectric substrate, a dielectric layer covering the control wire, and a shielding layer covering the dielectric layer.

A stacked quantum computing device including a first chip that includes a first dielectric substrate and a superconducting qubit on the first dielectric substrate, and a second chip that is bonded to the first chip and includes a second dielectric substrate, a qubit readout element on the second dielectric substrate, a control wire on the second dielectric substrate, a dielectric layer covering the control wire, and a shielding layer covering the dielectric layer.

Systems and devices for providing differential input/output communication with a superconducting device are described Each differential I/O communication is electrically filtered using a respective tubular filter structure incorporating superconducting lumped element devices and high frequency dissipation by metal powder epoxy. A plurality of such tubular filter structures is arranged in a cryogenic. multi-tiered assembly further including structural/thermalization supports and a device sample holder assembly for securing a device sample, for example a superconducting quantum processor. The ace between the cryogenic tubular assembly and room temperature electronics is achieved using hermetically sealed vacuum feed-through structures designed to receive flexible printed circuit board cable.