Four Spin Couplers for Quantum Information Processing
AssigneeMassachusetts Institute of Technology
InventorAndrew J. KERMAN
Life of this patent
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Abstract
Structures and techniques, using superconducting Josephson-junction based circuits, to directly engineer physical multiqubit (or “many-qubit”) interactions in a non-perturbative manner. In one embodiment, a system for multiqubit interaction includes: a multispin coupler including a plurality of loops, each loop having a pair of Josephson junctions; and a plurality of qubits each inductively coupled to the multispin coupler.
Claims20
A circuit for coupling a plurality of flux qubits, the circuit comprising:
- a spin qubit, magnetically biased at its degeneracy point;
- and
- a flux transformer, magnetically unbiased and inductively coupled to the spin qubit;
- wherein when the flux transformer is inductively coupled to the plurality of flux qubits, a measurement of the energy of the system has one of two values depending upon a total parity of the plurality of flux qubits.
A method of measuring a spin parity of flux qubits, the method comprising:
- coupling each of the flux qubits to a flux transformer, the flux transformer being inductively coupled to a spin qubit that is magnetically biased at biased at its degeneracy point;
- operating the circuit in a current mode, wherein a current circulating within the spin qubit is proportional to a quantum parity operator;
- and
- measuring the spin parity by sensing a magnetic flux, of the spin qubit, that has one of two values.
A system for multiqubit interaction between a plurality of qubits, the system comprising:
- a multispin coupler, inductively coupled to the plurality of qubits, the multispin coupler including a plurality of loops, each loop including a pair of Josephson junctions, the multispin coupler having a potential energy corresponding to a desired, non-linear function of a magnetic flux of the plurality of qubits, obtained by adjusting one or more magnetic fluxes that pass through a respective one or more of the plurality of loops.
Dependencies are inferred from the claim text.