# US 11,907,808 B2 · Apparatus and method for quantum error correction without measurement or active feedback > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,907,808 B2 - Document ID: US11907808B2 - Status: Granted - Kind: B2 - Application number: 17/464,583 - Filed: 2021-09-01 - Published: 2023-04-27 - Granted: 2024-02-20 - Earliest claimed: 2021-09-01 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Albert Schmitz; Anne Matsuura; Ravi Pillarisetty; Shavindra Premaratne; Justin Hogaboam; Lester Lampert - Web page: https://patentgrep.com/patent/US11907808B2 ## CPC - G06N 10/70: Quantum error correction, detection or prevention, e.g. surface codes or magic state distillation - G06N 10/20: Models of quantum computing, e.g. quantum circuits or universal quantum computers - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control - G06N 10/80: Quantum programming, e.g. interfaces, languages or software-development kits for creating or handling programs capable of running on quantum computers; Platforms for simulating or accessing quantum computers, e.g. cloud-based quantum computing - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract Apparatus and method for measurement-free (MF) quantum error correction (QEC). For example, one embodiment of a method comprises: determining an error syndrome on a first subset of ancilla qubits of a quantum processor; decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor; applying the decoded results to one or more system qubits; and unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system, wherein the operations of determining the error syndrome, decoding the error syndrome, applying the error syndrome, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device. ## Claims ### Claim 1 A method comprising: determining an error syndrome on a first subset of ancilla qubits of a quantum processor; decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor; applying the decoded results to one or more system qubits; and unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system, wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device. ### Claim 2 (depends on 1) The method of claim 1 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions. ### Claim 3 (depends on 2) The method of claim 2 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller, responsive to at least one of the quantum control instructions. ### Claim 4 (depends on 3) The method of claim 3 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of the quantum control instructions. ### Claim 5 (depends on 4) The method of claim 4 wherein, responsive to the quantum control instructions, the qubit controller is to generate a first set of one or more pulses to perform the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results. ### Claim 6 (depends on 5) The method of claim 5 wherein, responsive to the at least one quantum control instruction, the qubit controller is to generate a second set of one or more pulses to perform the operation of unconditionally resetting the first and/or second subset of ancilla qubits. ### Claim 7 (depends on 1) The method of claim 1 wherein determining the error syndrome comprises either: extracting the Z-stabilizer syndrome, wherein decoding the error syndrome comprises decoding the Z-stabilizer syndrome into an X-type unitary correction, or extracting the X-stabilizer syndrome, wherein decoding the error syndrome comprises decoding the X-stabilizer syndrome into a Z-type unitary correction. ### Claim 8 (depends on 7) The method of claim 7 wherein extracting the Z-stabilizer syndrome or X-stabilizer syndrome comprises applying a sequence of unitary Clifford gates between the one or more system qubits and one or more of the ancilla qubits. ### Claim 9 (depends on 7) The method of claim 7 wherein applying the decoded results comprises applying the X-type unitary or Z-type unitary to the one or more system qubits and the first and second subsets of ancilla qubits. ### Claim 10 An apparatus comprising: a quantum processor comprising a plurality of qubits; a quantum controller to autonomously execute a quantum error correction script to perform the operations of: determining an error syndrome on a first subset of ancilla qubits of a quantum processor; decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor; applying the decoded results to one or more system qubits; and unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system, wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device. ### Claim 11 (depends on 10) The apparatus of claim 10 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions. ### Claim 12 (depends on 11) The apparatus of claim 11 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller. ### Claim 13 (depends on 12) The apparatus of claim 12 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of the quantum control instructions. ### Claim 14 (depends on 13) The apparatus of claim 13 wherein, responsive to the quantum control instructions, the qubit controller is to generate a first set of one or more pulses to perform the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results. ### Claim 15 (depends on 14) The apparatus of claim 14 wherein, responsive to the at least one instruction, the qubit controller is to generate a second set of one or more pulses to perform the operation of unconditionally resetting the first and/or second subset of ancilla qubits. ### Claim 16 (depends on 10) The apparatus of claim 10 wherein determining the error syndrome comprises either: extracting the Z-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the Z-stabilizer syndrome into an X-type unitary correction, or extracting the X-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the X-stabilizer syndrome into a Z-type unitary correction. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein extracting the Z-stabilizer syndrome or X-stabilizer syndrome comprises applying a sequence of unitary Clifford gates between the one or more system qubits and one or more of the ancilla qubits. ### Claim 18 (depends on 16) The apparatus of claim 16 wherein applying the decoded results comprises applying the X-type unitary or Z-type unitary to the one or more system qubits and the first and second subsets of ancilla qubits. ### Claim 19 A machine-readable medium having program code stored thereon which, when executed by a qubit controller, causes the operations of: determining an error syndrome on a first subset of ancilla qubits of a quantum processor; decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor; applying the decoded results to one or more system qubits; and unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system, wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device. ### Claim 20 (depends on 19) The machine-readable medium of claim 19 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions. ### Claim 21 (depends on 20) The machine-readable medium of claim 20 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller. ### Claim 22 (depends on 21) The machine-readable medium of claim 21 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of the quantum control instructions. ### Claim 23 (depends on 22) The machine-readable medium of claim 22 wherein, responsive to the quantum control instructions, the qubit controller is to generate a first set of one or more pulses to perform the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results. ### Claim 24 (depends on 23) The machine-readable medium of claim 23 wherein, responsive to the at least one instruction, the qubit controller is to generate a second set of one or more pulses to perform the operation of unconditionally resetting the first and/or second subset of ancilla qubits. ### Claim 25 (depends on 19) The machine-readable medium of claim 19 wherein determining the error syndrome comprises either: extracting the Z-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the Z-stabilizer syndrome into an X-type unitary correction, or extracting the X-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the X-stabilizer syndrome into a Z-type unitary correction. ### Claim 26 (depends on 25) The machine-readable medium of claim 25 wherein extracting the Z-stabilizer syndrome or X-stabilizer syndrome comprises applying a sequence of unitary Clifford gates between the one or more system qubits and one or more of the ancilla qubits. ### Claim 27 (depends on 25) The machine-readable medium of claim 25 wherein applying the decoded results comprises applying the X-type unitary or Z-type unitary to the one or more system qubits and the first and second subsets of ancilla qubits.