Abstract: Methods, systems, and apparatus for designing an artificial quantum thermal bath. In one aspect, an apparatus includes a primary quantum system; an auxiliary quantum system comprising a plurality of modes and that interacts with the primary quantum system, wherein: the auxiliary system interacts with the primary quantum system through one or more couplings, wherein the one or more couplings are controllable; a steady state of the auxiliary system, a response function of the auxiliary quantum system, an auxiliary system operator, and a spectrum of the auxiliary quantum system are determined to meet a respective condition; and the auxiliary system is controllable to relax the primary quantum system to an equilibrium state using a controllable function of the auxiliary system operator.

Abstract: A quantum computing device includes multiple co-planar waveguide flux qubits, at least one coupler element arranged such that each co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, is operatively couplable to each other co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, of the quantum computing device, and a tuning quantum device, in which the tuning quantum device is in electrical contact with a first co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits and with a second co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits.

Abstract: A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.

Abstract: A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.

Abstract: A quantum computing device includes: a first array of qubits arranged along a first axis; and a second array of qubits arranged along a second axis different from the first axis so that the qubits of the second array intersect with the qubits of the first array to form a lattice structure, in which each qubit in the first array is offset along the second axis relative to a directly adjacent qubit in the first array, each qubit in the second array is offset along the first axis relative to a directly adjacent qubit in the second array, and each intersection between a qubit from the first array and a qubit from the second array in the lattice structure comprises a coupler arranged to inductively couple the qubit from the first array to the qubit from the second array.

Abstract: A quantum computing device includes multiple co-planar waveguide flux qubits, at least one coupler element arranged such that each co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, is operatively couplable to each other co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, of the quantum computing device, and a tuning quantum device, in which the tuning quantum device is in electrical contact with a first co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits and with a second co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits.

Abstract: A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.

Abstract: A quantum computing device includes multiple co-planar waveguide flux qubits, at least one coupler element arranged such that each co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, is operatively couplable to each other co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, of the quantum computing device, and a tuning quantum device, in which the tuning quantum device is in electrical contact with a first co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits and with a second co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits.

Abstract: A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.

Abstract: A quantum computing device includes: a first array of qubits arranged along a first axis; and a second array of qubits arranged along a second axis different from the first axis so that the qubits of the second array intersect with the qubits of the first array to form a lattice structure, in which each qubit in the first array is offset along the second axis relative to a directly adjacent qubit in the first array, each qubit in the second array is offset along the first axis relative to a directly adjacent qubit in the second array, and each intersection between a qubit from the first array and a qubit from the second array in the lattice structure comprises a coupler arranged to inductively couple the qubit from the first array to the qubit from the second array.

Abstract: A quantum computing device includes multiple co-planar waveguide flux qubits, at least one coupler element arranged such that each co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, is operatively couplable to each other co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, of the quantum computing device, and a tuning quantum device, in which the tuning quantum device is in electrical contact with a first co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits and with a second co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits.

Abstract: Methods, systems, and apparatus for designing an artificial quantum thermal bath. In one aspect, an apparatus includes a primary quantum system; an auxiliary quantum system comprising a plurality of modes and that interacts with the primary quantum system, wherein: the auxiliary system interacts with the primary quantum system through one or more couplings, wherein the one or more couplings are controllable; a steady state of the auxiliary system, a response function of the auxiliary quantum system, an auxiliary system operator, and a spectrum of the auxiliary quantum system are determined to meet a respective condition; and the auxiliary system is controllable to relax the primary quantum system to an equilibrium state using a controllable function of the auxiliary system operator.

Abstract: A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.