Drag¶

class Drag(duration, amp, sigma, beta, name=None, limit_amplitude=None)[ソース]¶

ベースクラス: qiskit.pulse.library.parametric_pulses.ParametricPulse

The Derivative Removal by Adiabatic Gate (DRAG) pulse is a standard Gaussian pulse with an additional Gaussian derivative component and lifting applied.

It is designed to reduce the frequency spectrum of a standard Gaussian pulse near the \(|1\rangle\leftrightarrow|2\rangle\) transition, reducing the chance of leakage to the \(|2\rangle\) state.

\[\begin{split}g(x) &= \exp\Bigl(-\frac12 \frac{(x - \text{duration}/2)^2}{\text{sigma}^2}\Bigr)\\ g'(x) &= \text{amp}\times\frac{g(x)-g(-1)}{1-g(-1)}\\ f(x) &= g'(x) \times \Bigl(1 + 1j \times \text{beta} \times \Bigl(-\frac{x - \text{duration}/2}{\text{sigma}^2}\Bigr) \Bigr), \quad 0 \le x < \text{duration}\end{split}\]

where \(g(x)\) is a standard unlifted Gaussian waveform and \(g'(x)\) is the lifted Gaussian waveform.

This pulse, defined by \(f(x)\), would be more accurately named as LiftedDrag, however, for historical and practical DSP reasons it has the name Drag.

参照

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).

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

Initialize the drag pulse.

パラメータ

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.
limit_amplitude (Optional[bool]) – If True, then limit the amplitude of the waveform to 1. The default is True and the amplitude is constrained to 1.

Methods

`draw`	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.

戻り値の型: Union[complex, ParameterExpression]

beta¶

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

戻り値の型: Union[float, ParameterExpression]

id¶

Unique identifier for this pulse.

戻り値の型: int

limit_amplitude = True¶

parameters¶

戻り値の型: Dict[str, Any]

sigma¶

The Gaussian standard deviation of the pulse width.

戻り値の型: Union[float, ParameterExpression]