Radiation Suppression of Superconducting Quantum Bits Using a Conductive Plane
AssigneeThe United States of America as represented by the Secretary of Commerce
InventorsMartin Sandberg, Jiansong Gao, Michael Vissers, David Pappas
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Abstract
This invention relates to a quantum computing device and the means for fabrication thereof. One side of the device includes a circuit containing at least one qubit patterned in a film of superconducting material. The other side of the device includes a conductive plane, also formed from a film of superconducting material. The proximity of the conductive plane suppresses radiative decay of the qubit, while readout is achieved by coupling the qubit to a resonator.
Claims20
A device for use in a quantum computing system, comprising:
- a substrate having a first substrate surface and a second substrate surface;
- a two-dimensional circuit having at least one qubit and at least one resonator to which said at least one qubit is operatively coupled, wherein said two-dimensional circuit is formed from a superconducting material on said first substrate surface;
- and
- a continuous superconducting ground plane located on said second substrate surface opposite from said two-dimensional circuit,
- wherein said continuous superconducting ground plane is formed from a superconducting material,
- wherein said continuous superconducting ground plane is positioned a distance h from said at least one qubit, wherein h<λ0/4√{square root over (∈r)} where ∈r is relative permittivity of said substrate and λ0 is a qubit wavelength in vacuum equal to f/c, where f is a frequency of said at least one qubit and c is the speed of light.
A method of making a device for use in a quantum computing system, comprising the steps of:
- depositing a first titanium nitride (TiN) film on a first substrate surface of a silicon (Si) substrate and depositing a second TiN film on a second substrate surface of said Si substrate, wherein said first substrate surface and said second substrate surface are opposing surfaces a distance h from each other, wherein h<λ0/4√{square root over (∈r)} where ∈r is relative permittivity of said Si substrate and λ0 is a qubit wavelength in vacuum equal to f/c, where f is a frequency of at least one qubit and c is the speed of light;
- patterning said first TiN film to create patterns for at least one pair of capacitor pads and at least one microstrip resonator;
- and
- forming at least one Josephson junction interconnect between said at least one pair of capacitor pads to form said at least one qubit.
Dependencies are inferred from the claim text.