Amazon Technologies, Inc.

Joseph Kramer Iverson

Kyungjoo Noh

Oskar Jon Painter

Fernando Brandao

Connor Hann

Harald Esko Jakob Putterman

Christopher Chamberland

Patricio Arrangoiz Arriola

Earl Campbell

Amir Safavi-Naeini

Liang Jiang

Prasahnt Sivarajah

Andrew Joseph Keller

Colm Andrew Ryan

Matthew Matheny

Menyoung Lee

Thomas Scaffidi

Qian Xu

Ashley James Milsted

Arne Grimsmo

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

Selective frequency dissipation is implemented that enables cooling of energy gap protected qubits such that excited energy states resulting from heating or other undesired processes are returned to a lower excited energy state or a ground state manifold, thus reducing the probability of errors. Also, the selective frequency dissipation inhibits leakage from the energy gap protected qubits when in the ground state.

Frequency selective photon dissipation for an energy gap protected qubit

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

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Pasadena, CA, United States of America

Joseph Kramer Iverson