FastDataBlock

qualtran.surface_code.FastDataBlock

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The fast data block uses a fixed code distance and a square layout.

Inherits From: DataBlock

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Main aliases

`qualtran.surface_code.data_block.FastDataBlock`

qualtran.surface_code.FastDataBlock(
    data_d
)

The fast data block lays \(n\) qubit batches in a square grid of side length \(1 + \sqrt{2n}\) where the bottom row is an ancilla region and the top \(\sqrt{2n}x\sqrt{2n}\) region is divided into alternating data and ancilla columns.

The increased footprint is to be able to consume magic states in a single timestep.

References

Attributes

data_d

The code distance d for protecting the qubits in the data block.

n_steps_to_consume_a_magic_state

The number of surface code steps to consume a magic state.

We must teleport in “magic states” to do non-Clifford operations on our algorithmic data qubits. The layout of the data block can limit the number magic states consumed per unit time.

One surface code step is data_d cycles of error correction.

DataBlock imlpementation must override this method. This method is used by self.n_cycles to report the total number of cycles required.

Methods

get_n_tiles

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@staticmethod
get_n_tiles(
    n_algo_qubits: int
)

n_tiles

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n_tiles(
    n_algo_qubits: int
) -> int

The number of surface code tiles used to store a given number of algorithm qubits.

We define an “algorithm qubit” to be a qubit used in the routing of algorithm-relevant quantum data in a bloq. A physical qubit is a physical system that can encode one qubit, albeit noisily. Specific to the surface code, we define a “tile” to be the minimal area of physical qubits necessary to encode one logical qubit to a particular code distance. A tile can store an algorithm qubit, can be used for ancillary purposes like routing, or can be left idle. A tile is usually a square grid of \(2d^2\) physical qubits.

DataBlock implementations must override this method. This method is used by self.n_phys_qubits to report the total number of physical qubits.

Args

n_algo_qubits

The number of algorithm qubits to compute the number of tiles for.

Returns

from_error_budget

View source

@classmethod
from_error_budget(
    error_budget: float,
    n_algo_qubits: int,
    qec_scheme: 'QECScheme',
    phys_err_rate: float
) -> 'FastDataBlock'

__ne__

__ne__(
    other
)

Check equality and either forward a NotImplemented or return the result negated.

__eq__

__eq__(
    other
)

Method generated by attrs for class FastDataBlock.