[Problem] To provide a phononic material that exhibits a voltage-current characteristic to make current flow even when there is no potential gradient, and a method for producing the same. [Solution] A phononic material 1 has a periodic structure body 2′ in which structures 3 are periodically and regularly disposed in a constituent 2, and the periodic structure body 2′ exhibits a voltage-current characteristic to make current flow even when a potential gradient is 0 V. A method for producing the phononic material 1 has such an outline as to carry out a heat treatment to cool and warm the periodic structure body after applying a current with a magnitude to make an electrical resistance characteristic disappear to the periodic structure body 2′ having the electrical resistance characteristic that exhibits an electrical resistance value of 0Ω or less.

A technique for treating the surface of one or more accelerator cavities of an accelerator module. This technique relies on the use of a particle beam to at least partially scan the inner surface of the one or more accelerator cavities. Such a technique offers a treatment solution that is more suitable for accelerator cavities, with better control of the implantation parameters.

[Problem] To provide a phononic material that exhibits an electrical resistance characteristic less than or equal to 0Ω, a precursor of the same, and a method for producing these. [Solution] A phononic material 1 has a periodic structure body 2′ in which structures 3 are periodically and regularly disposed in a constituent 2. The periodic structure body 2′ exhibits an electrical resistance characteristic less than or equal to 0Ω, and has a temperature region that exhibits the electrical resistance characteristic in a temperature range exceeding a superconducting transition temperature when the constituent 2 has the superconducting transition temperature. A method for producing a precursor of the phononic material 1 includes a pretreatment process to obtain the precursor by carrying out a heat treatment to warm the periodic structure body after cooling the periodic structure body in a state of applying a unidirectional current to the periodic structure body 2′.

A quantum computing device includes a first chip having a first substrate and one or more qubits disposed on the first substrate. Each of the one or more qubits has an associated resonance frequency. The quantum computing device further includes a second chip having a second substrate and at least one conductive surface disposed on the second substrate opposite the one or more qubits. The at least one conductive surface has at least one dimension configured to adjust the resonance frequency associated with at least one of the one or more qubits to a determined frequency adjustment value.

Materials and methods are disclosed for fabricating superconducting integrated circuits for quantum computing at millikelvin temperatures, comprising both quantum circuits and classical control circuits, which may be located on the same integrated circuit or on different chips of a multi-chip module. The materials may include components that reduce defect densities and increase quantum coherence times. Multilayer fabrication techniques provide low-power and a path to large scale computing systems. An integrated circuit system for quantum computing is provided, comprising: a substrate; a kinetic inductance layer having a kinetic inductance of at least 5 pH/square; a plurality of stacked planarized superconducting layers and intervening insulating layers, formed into a plurality of Josephson junctions having a critical current of less than 100 μA/μm.sup.2; and a resistive layer that remains non-superconducting at a temperature below 1 K, configured to damp the plurality of Josephson junctions.

A method comprising cleaning the top surface of a silicon substrate and forming a diffusion barrier by depositing a metal on top the top surface of the silicon substrate. The diffusion barrier is formed one monolayer at a time and wherein the diffusion barrier will have a height of about 1 to 3 nm. Forming a layer of crystalline Niobium on top of the diffusion barrier.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Nb alloys or Nb—Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

A method for fabricating a bridge structure in a quantum mechanical device includes providing a substructure including a substrate having deposited thereon a layer of a first superconducting material divided into a first portion, a second portion and a third portion that are electrically insulated from each other; depositing a sacrificial layer on the substructure; electrically connecting the first portion and the second portion with a strip of a second superconducting material, the second superconducting material being different from the first superconducting material; and removing a portion of the sacrificial layer so as to form a bridge structure over the third portion between the first portion and the second portion, the bridge structure electrically connecting the first portion to the second portion while not electrically connecting the third portion to the first portion and not electrically connecting the third portion to the second portion.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

A system and method for treating a cavity comprises preparing a superconducting radio frequency (SRF) cavity for removal of a dielectric layer from on an inner surface of the SRF cavity, subjecting the SRF cavity to a heat treatment in order to remove the dielectric layer from the inner surface of the SRF cavity, and preventing the development of a new dielectric layer on the inner surface of the SRF cavity by preventing an interaction between the inner surface of the SRF cavity and atmospheric gasses.