loom_rotated_surface_code.applicator.transversalhadamard

Copyright 2024 Entropica Labs Pte Ltd

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

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loom_rotated_surface_code.applicator.transversalhadamard.transversal_hadamard_syndrome_circuits(block, interpretation_step, new_stabs, new_stabilizer_to_circuit, new_synd_circs=())

For a given Block, InterpretationStep and list of new Stabilizers that result from a Transversal Hadamard operation, this generates the new SyndromeCircuit objects that are associated with the new Stabilizers. Along with the new SyndromeCircuit objects, it also generates a mapping of the new Stabilizers to the UUIDs of the new SyndromeCircuits. An initial collection of new SyndromeCircuits and a partially populated mapping of the new Stabilizers to the UUIDs of the new SyndromeCircuits can be provided as optional arguments.

Parameters:

• block (RotatedSurfaceCode) – The block of the surface code.

• interpretation_step (InterpretationStep) – The interpretation step that contains the evolution of the new Stabilizers.

• new_stabs (list[Stabilizer]) – The new stabilizers that result from the Transversal Hadamard operation.

• new_stabilizer_to_circuit (dict[str, str]) – The partially populated mapping of the new Stabilizers to the UUIDs of the new SyndromeCircuits.

• new_synd_circs (tuple[SyndromeCircuit], optional) – The new SyndromeCircuit objects that are ALREADY associated with the new Stabilizers.

Returns:

A tuple containing the new SyndromeCircuit objects and a dictionary mapping the new Stabilizers to the UUIDs of the new SyndromeCircuits.

Return type:

tuple[tuple[SyndromeCircuit], dict[str,str]]

loom_rotated_surface_code.applicator.transversalhadamard.transversalhadamard(interpretation_step, operation, same_timeslice, debug_mode)

Apply a Transversal Hadamard gate to a Block.

The algorithm is as follows:

1. CIRCUIT

   • A.1) Apply Hadamard gates over all data qubits of the block.

   • A.2) Append Hadamard gates to the circuit within the InterpretationStep.

2. STABILIZERS

   • B.1) Update Stabilizers (XX -> ZZ, ZZ -> XX, for 2-body stabilizers) with new UUIDs.

   • B.2) Record the old UUIDs and the new UUIDs of the Stabilizers. (stabilizer_evolution)

3. PAULIOPERATORS

   • C.1) Update PauliOperators (X to Z Operators) with new UUIDs

     and logical updates.

   • C.2) Update PauliOperators (Z to X Operators) with new UUIDs

     and logical updates.

4. SYNDROMECIRCUITS

   • D.1) Update Syndrome Circuits with new UUIDs.

   • D.2) Determine the Syndrome Circuit(s) associated with the old Stabilizer(s).

   • D.3) Update the Syndrome Circuit(s) for the new Stabilizer(s).

   • D.4) Update Collection of New Syndrome Circuits and New Stabilizer to Circuit Mapping

5. NEW BLOCK

   • E.1) Create new Block (Same unique_label as Input Block)

7. BLOCK HISTORY

   • G.1) Update the latest Block Configuration in InterpretationStep.

Parameters:

• interpretation_step (InterpretationStep) – Interpretation step containing the block to apply the transversal hadamard to.

• operation (TransversalHadamard) – Transversal hadamard operation description.

• same_timeslice (bool) – Flag indicating whether the operation is part of the same timestep as the previous operation.

• debug_mode (bool) – Flag indicating whether the interpretation should be done in debug mode. Activating debug mode will enable commutation validation for Block.

Returns:

Interpretation step after the transversal hadamard operation.

Return type:

InterpretationStep

loom_rotated_surface_code.applicator.transversalhadamard.update_synd_circ(input_synd_circ, new_pauli)

Updates the input Measurement SyndromeCircuit to measure a new pauli. The input SyndromeCircuit requires a specific design where the ancilla qubits are initialized and measured in the X basis with a CX, CY or CZ gate to the data qubit. The function replaces the two-qubit gate with a new gate that measures the new_pauli. If the new pauli is a Z, the function replaces the two-qubit gate with a CZ gate. If the new pauli is an X, the function replaces the two-qubit gate with a CX gate. If the new pauli is a Y, the function replaces the two-qubit gate with a CY gate.

Parameters:

• input_synd_circ (SyndromeCircuit) – The input syndrome circuit.

• new_pauli (str) – The new pauli the circuit will be measuring now.

Return type:

SyndromeCircuit

Returns:

SyndromeCircuit: The updated syndrome circuit.