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# Licensed under the Apache License, Version 2.0 (the "License"). You
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from pydantic import BaseModel

from braket.ir.ahs.physical_field import PhysicalField


class ShiftingField(BaseModel):
    r"""Specifies the shifting field, defined by the formula

    .. math::
        H_{shift} (t) := -\Delta(t) \sum_k h_k | r_k \rangle \langle r_k |

    where

        :math:`\Delta(t)` is the magnitude of the frequency shift in rad/s,

        :math:`h_k` is the site coefficient,

        :math:`|r_k \rangle` is the Rydberg state of atom k.

    with the sum :math:`\sum_k` taken over all target atoms.

    Attributes:
        magnitude: PhysicalField

    Examples:
        >>> ShiftingField(magnitude=PhysicalField)
    """

    magnitude: PhysicalField