Amazon Technologies, Inc.

Earl Campbell

Christopher Chamberland

Fernando Brandao

Oskar Jon Painter

Kyungjoo Noh

Amir Safavi-Naeini

Patricio Arrangoiz Arriola

Connor Hann

Joseph Kramer Iverson

Harald Esko Jakob Putterman

A technique for performing lattice surgery without using twists is disclosed. Also, an error correcting code and decoder is provided that allows for error decoding of Pauli measurements performed in association with a lattice surgery operation. This allows for overall run-times of lattice surgery to be reduced. For example, some level of errors are tolerable, because they can be corrected, thus fewer measurement rounds (d) may be performed for a given round of Pauli measurements. Additionally, a temporal encoding of lattice surgery technique is provided, which may additionally or alternatively be used to shorten run times. Also, a quantum computer layout is provided, wherein the layout includes a core computing region and a cache region. Also, protocols for swapping logical qubits between the core and cache are provided.

Quantum computer designs with core computing and cache regions that utilize lattice surgery

A Toffoli magic state to be injected in preparation of a Toffoli gate may be prepared using a bottom-up approach. In the bottom-up approach, computational basis states are prepared in a fault tolerant manner using a STOP algorithm. The computational basis states are further used to prepare the Toffoli magic state. The STOP algorithm tracks syndrome outcomes and can be used to determine when to stop repeating syndrome measurements such that faults are guaranteed to be below a threshold level. Also, the STOP algorithm may be used in growing repetition code from a first code distance to a second code distance, such as for use in the computational basis states.

Toffoli gate preparation for a quantum hardware system comprising hybrid acoustic-electrical qubits

Lattice surgery techniques without using twists

A technique for performing lattice surgery using twists is disclosed. Also, an error correcting code and decoder is provided that allows for error decoding of Pauli measurements performed in association with a lattice surgery operation. This allows for overall run-times of lattice surgery to be reduced. For example, some level of errors are tolerable, because they can be corrected, thus fewer measurement rounds (d) may be performed for a given round of Pauli measurements. Additionally, a temporal encoding of lattice surgery technique is provided, which may additionally or alternatively be used to shorten run times. Also, a quantum computer layout is provided, wherein the layout includes a core computing region and a cache region. Also, protocols for swapping logical qubits between the core and cache are provided.

Lattice surgery techniques using twists

Error correction decoding techniques for lattice surgery

A top-down distillation process for preparing low-error rate Toffoli gates utilizes Toffoli magic states as inputs to the distillation process. Multiple Toffoli magic states are used to distill a low-error rate Toffoli gate via one round of distillation. Lattice surgery operations are performed to distill the low-error rate Toffoli gate from the multiple Toffoli magic states. Each round of lattice surgery operations acts on a check qubit associated with the low error rate Toffoli gate being distilled. Errors introduced during the distillation (if non-trivial) will be manifest in the check qubit. Thus, the check qubit is measured subsequent to performing the lattice surgery operations to verify that the distilled Toffoli gate is very likely to be provide a correct result.

Toffoli gate distillation from Toffoli magic states

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.

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Cambridge, United Kingdom

Earl Campbell