qiskit.pulse.library.Drag

class Drag(duration, amp, sigma, beta, name=None)

The Derivative Removal by Adiabatic Gate (DRAG) pulse is a standard Gaussian pulse with an additional Gaussian derivative component. It is designed to reduce the frequency spectrum of a normal gaussian pulse near the \(|1\rangle\) - \(|2\rangle\) transition, reducing the chance of leakage to the \(|2\rangle\) state.

\[f(x) = Gaussian + 1j * beta * d/dx [Gaussian] = Gaussian + 1j * beta * (-(x - duration/2) / sigma^2) [Gaussian]\]

where ‘Gaussian’ is:

\[Gaussian(x, amp, sigma) = amp * exp( -(1/2) * (x - duration/2)^2 / sigma^2) )\]

References

1. Gambetta, J. M., Motzoi, F., Merkel, S. T. & Wilhelm, F. K. Analytic control methods for high-fidelity unitary operations in a weakly nonlinear oscillator. Phys. Rev. A 83, 012308 (2011).

2. F. Motzoi, J. M. Gambetta, P. Rebentrost, and F. K. Wilhelm Phys. Rev. Lett. 103, 110501 – Published 8 September 2009.

Initialize the drag pulse.

Parameters

• duration (Union[int, ParameterExpression]) – Pulse length in terms of the the sampling period dt.

• amp (Union[complex, ParameterExpression]) – The amplitude of the Drag envelope.

• sigma (Union[float, ParameterExpression]) – A measure of how wide or narrow the Gaussian peak is; described mathematically in the class docstring.

• beta (Union[float, ParameterExpression]) – The correction amplitude.

• name (Optional[str]) – Display name for this pulse envelope.

__init__(duration, amp, sigma, beta, name=None)

Initialize the drag pulse.

Parameters

• duration (Union[int, ParameterExpression]) – Pulse length in terms of the the sampling period dt.

• amp (Union[complex, ParameterExpression]) – The amplitude of the Drag envelope.

• sigma (Union[float, ParameterExpression]) – A measure of how wide or narrow the Gaussian peak is; described mathematically in the class docstring.

• beta (Union[float, ParameterExpression]) – The correction amplitude.

• name (Optional[str]) – Display name for this pulse envelope.

Methods

__init__(duration, amp, sigma, beta[, name])	Initialize the drag pulse.
assign(parameter, value)	Assign one parameter to a value, which can either be numeric or another parameter expression.
assign_parameters(value_dict)	Return a new ParametricPulse with parameters assigned.
draw([dt, style, filename, interp_method, …])	Plot the interpolated envelope of pulse.
get_waveform()	Return a Waveform with samples filled according to the formula that the pulse represents and the parameter values it contains.
is_parameterized()	Return True iff the instruction is parameterized.
validate_parameters()	Validate parameters.

Attributes

amp	The Gaussian amplitude.
beta	The weighing factor for the Gaussian derivative component of the waveform.
id	Unique identifier for this pulse.
parameters	Return a dictionary containing the pulse’s parameters.
sigma	The Gaussian standard deviation of the pulse width.

property amp

The Gaussian amplitude.

Return type

Union[complex, ParameterExpression]

assign(parameter, value)

Assign one parameter to a value, which can either be numeric or another parameter expression.

Return type

ParametricPulse

assign_parameters(value_dict)

Return a new ParametricPulse with parameters assigned.

Parameters

value_dict (Dict[ParameterExpression, Union[ParameterExpression, float, int]]) – A mapping from Parameters to either numeric values or another Parameter expression.

Return type

ParametricPulse

Returns

New pulse with updated parameters.

property beta

The weighing factor for the Gaussian derivative component of the waveform.

Return type

Union[float, ParameterExpression]

draw(dt=None, style=None, filename=None, interp_method=None, scale=None, interactive=None, draw_title=None, backend=None, time_range=None, time_unit='dt', show_waveform_info=True, plotter='mpl2d', axis=None)

Plot the interpolated envelope of pulse.

Parameters

• style (Optional[Dict[str, Any]]) – Stylesheet options. This can be dictionary or preset stylesheet classes. See :py:class:~`qiskit.visualization.pulse_v2.stylesheets.IQXStandard`, :py:class:~`qiskit.visualization.pulse_v2.stylesheets.IQXSimple`, and :py:class:~`qiskit.visualization.pulse_v2.stylesheets.IQXDebugging` for details of preset stylesheets.

• backend (Optional[BaseBackend]) – Backend object to play the input pulse program. If provided, the plotter may use to make the visualization hardware aware.

• time_range (Optional[Tuple[int, int]]) – Set horizontal axis limit. Tuple (tmin, tmax).

• time_unit (str) – The unit of specified time range either dt or ns. The unit of ns is available only when backend object is provided.

• show_waveform_info (bool) – Show waveform annotations, i.e. name, of waveforms. Set True to show additional information about waveforms.

• plotter (str) –

  Name of plotter API to generate an output image. One of following APIs should be specified:

  mpl2d: Matplotlib API for 2D image generation.
      Matplotlib API to generate 2D image. Charts are placed along y axis with
      vertical offset. This API takes matplotlib.axes.Axes as `axis` input.
  

  axis and style kwargs may depend on the plotter.

• axis (Optional[Any]) – Arbitrary object passed to the plotter. If this object is provided, the plotters use a given axis instead of internally initializing a figure object. This object format depends on the plotter. See plotter argument for details.

• dt (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer.

• filename (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer. To save output image, you can call .savefig method with returned Matplotlib Figure object.

• interp_method (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer.

• scale (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer.

• interactive (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer.

• draw_title (Optional[Any]) – Deprecated. This argument is used by the legacy pulse drawer.

Returns

Visualization output data. The returned data type depends on the plotter. If matplotlib family is specified, this will be a matplotlib.pyplot.Figure data.

get_waveform()

Return a Waveform with samples filled according to the formula that the pulse represents and the parameter values it contains.

Return type

Waveform

property id

Unique identifier for this pulse.

Return type

int

is_parameterized()

Return True iff the instruction is parameterized.

Return type

bool

property parameters

Return a dictionary containing the pulse’s parameters.

Return type

Dict[str, Any]

property sigma

The Gaussian standard deviation of the pulse width.

Return type

Union[float, ParameterExpression]

validate_parameters()

Validate parameters.

Raises

PulseError – If the parameters passed are not valid.

Return type

None