Amazon Technologies, Inc.

Yale University

Connor Hann

Kyungjoo Noh

Christopher Chamberland

Fernando Brandao

Patricio Arrangoiz Arriola

Joseph Kramer Iverson

Oskar Jon Painter

Harald Esko Jakob Putterman

Robert J Schoelkopf, Iii

Steven M Girvin

Earl Campbell

Amir Safavi-Naeini

Yiwen Chu

Prasahnt Sivarajah

Andrew Joseph Keller

Yaxing Zhang

Changling Zou

Ashley James Milsted

Arne Grimsmo

Colm Andrew Ryan

Matthew Matheny

Menyoung Lee

Thomas Scaffidi

Techniques for implementing a QRAM by routing quantum information through multiple modes of a bosonic system are described. According to some aspects, a single bosonic system may be configured to maintain quantum information in a large number of independent modes at the same time. Suitable operations upon these modes may allow a quantum address value to be routed to modes associated with respective bits such that the only modes altered by the operations are those associated with the addresses being accessed. These modes may be operated upon based on the stored values then extracted to obtain the desired correlated superposition of the stored bit values in the addresses. The bits stored at the address locations may be classical bits, or may be qubits.

Techniques for quantum memory addressing and related systems and methods

Systems and methods for implementing a quantum code using cat qubits as data qubits and transmon qubits as ancilla qubits is disclosed. In some embodiments, a three-level transmon is used and Chi-matching is performed to determine dispersive coupling coefficients between the cat qubits and first and second excited states of the transmon qubits, wherein the dispersive coupling coefficients are used to perform gates between the cat data qubits and the transmon ancilla qubits. The Chi-matching determines the dispersive coupling coefficients such that the cat qubits are rotated in a same manner while performing the gates regardless as to whether a given transmon ancilla qubit remains in a second excited state or has decayed to a first excited state.

Quantum codes implemented using cat data qubits and transmon ancilla qubits

A fault tolerant quantum computer is implementing using hybrid acoustic-electric qubits. A control circuit includes an asymmetrically threaded superconducting quantum interference devices (ATS) that excites phonons in a mechanical resonator by driving a storage mode of the mechanical resonator and dissipates phonons from the mechanical resonator via an open transmission line coupled to the control circuit, wherein the open transmission line is configured to absorb photons from a dump mode of the control circuit. Filters are included in the control circuit to suppress cross-talk errors. Additionally, frequencies and pump mode detunings for respective multiplexed control circuits are strategically selected to reduce cross-talk errors.

Cross-talk reduction in fault tolerant quantum computing system

Extra edges are added to a group of edges for use in decoding syndrome measurements of a surface code implemented using hybrid acoustic-electric qubits. The extra edges include two-dimensional cross-edges and three-dimensional space-time correlated edges that identify correlated errors arising from spurious photon dissipation processes of a multiplexed control circuit that leads to cross-talk between storage modes of a set of the mechanical resonators controlled by the given multiplexed control circuit. Additionally, error probabilities used for edge weighting incorporate error probabilities due to the spurious photon dissipation processes.

Stabilizer measurement decoding using additional edges to identify errors caused by cross-talk

A method of simulating quantum gates includes shifting a Fock basis for the simulation such that the simulation can be performed in a smaller (e.g. truncated) Hilbert dimension space. To shift the Fock basis, non-orthonormalized basis states are first defined. The defined basis states are then orthonormalized to construct orthonormalized shifted Fock basis state. Matrix elements are determined for an operator in the orthonormalized shifted Fock basis and the operator is used to simulate the quantum gate in the shifted Fock basis.

Simulating large cat qubits using a shifted fock basis

A fault tolerant quantum computer is implemented using hybrid acoustic-electric qubits. A control circuit includes an asymmetrically threaded superconducting quantum interference devices (ATS) that excites excite phonons in a mechanical resonator by driving a storage mode of the mechanical resonator and dissipates phonons from the mechanical resonator via an open transmission line coupled to the control circuit, wherein the open transmission line is configured to absorb photons from a dump mode of the control circuit.

Fault-tolerant quantum hardware using hybrid acoustic-electrical qubits

Growing community of inventors

New Haven, CT, United States of America

Connor Hann