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qiskit.pulse.library.Sech

qiskit.pulse.library.Sech(duration, amp, sigma, angle=0.0, name=None, zero_ends=True, limit_amplitude=None)

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An unnormalized sech pulse.

The sech function is centered around the halfway point of the pulse, and the envelope of the pulse is given by:

f(x)=Asech(xμsigma),0<=x<durationf(x) = \text{A}\text{sech}\left( \frac{x-\mu}{\text{sigma}}\right) , 0 <= x < duration

where A=amp×exp(i×angle)\text{A} = \text{amp} \times\exp\left(i\times\text{angle}\right), and μ=duration/2\mu=\text{duration}/2.

If zero_ends is set to True, the output y is modified: .. math:

y\left(x\right) \mapsto \text{A}\frac{y-y^{*}}{\text{A}-y^{*}},

where yy^{*} is the value of yy at the endpoints (at x=1and:math:x=duration+1x=-1 and :math:`x=\text{duration}+1). This shifts the endpoints value to zero, while also rescaling to preserve the amplitude at :math:text{duration}/2``.

Parameters

  • duration (int | ParameterValueType) – Pulse length in terms of the sampling period dt.
  • amp (float |ParameterExpression) – The magnitude of the amplitude of the pulse (the value at the midpoint duration/2).
  • sigma (float |ParameterExpression) – A measure of how wide or narrow the sech peak is in terms of dt; described mathematically in the class docstring.
  • angle (float |ParameterExpression | None) – The angle in radians of the complex phase factor uniformly scaling the pulse. Default value 0.
  • name (str | None) – Display name for this pulse envelope.
  • zero_ends (bool | None) – If True, zeros the ends at x = -1, x = duration + 1, but rescales to preserve amp. Default value True.
  • limit_amplitude (bool | None) – If True, then limit the amplitude of the waveform to 1. The default is True and the amplitude is constrained to 1.

Returns

ScalableSymbolicPulse instance.

Return type

ScalableSymbolicPulse

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