qcheff.utils.pulses

Module Contents

Classes

ControlPulse	Defines a control pulse.
FourierPulse	Pulse in the modulated Fourier basis. This creates a Pulse with the basis functions given in the Fourier basis.

Functions

cos_ramp

Compute a cosine ramp function.

API

cos_ramp(t, a=0.2)

Compute a cosine ramp function.

Parameters

t : array_like Time array. a : float, optional Ramp ratio. Default is 0.2.

Returns

array_like Cosine ramp function values.

class ControlPulse

Defines a control pulse.

Contains an envelope in the form of PulseEnvelope or a derived class, carrier frequency and phase. The amplitude is assumed to be 1 if unspecified.

The carrier is assumed to be a cosine wave.

basis_funcs and ramp_func are defined so that the gate is active between t=0 and t=1. It is also assumed that they are all vectorized functions.

Parameters

coeffs : list of float Coefficients for the basis functions. basis_funcs : list of Callable[[float], float] Basis functions. frequency : float, optional Carrier frequency. Default is 1. phase : float, optional Phase of the pulse. Default is 0. amplitude : float, optional Amplitude of the pulse. Default is 1. name : str or None, optional Name of the pulse. Default is None.

Raises

ValueError If the lengths of coeffs and basis_funcs are not the same.

coeffs: list[float]

None

basis_funcs: list[collections.abc.Callable[[float], float]]

None

frequency: float

1.0

phase: float

0.0

amplitude: float

1.0

name: dataclasses.InitVar[str | None]

None

envelope(tlist)

Generates a pulse array given a timelist.

Parameters

tlist : array_like List of time points.

Returns

array_like Pulse array.

class FourierPulse(coeffs, gate_time, ramp_ratio=0.2, backend='cpu', **kwargs)

Bases: qcheff.utils.pulses.ControlPulse

Pulse in the modulated Fourier basis. This creates a Pulse with the basis functions given in the Fourier basis.

The basis functions are:

s(t/T) * cos(pi * n* t / gate_time) for even n s(t/T) * sin(pi * n* t / gate_time) for odd n

and s(t/T) is the ramp function.

where n is the index of the basis function. n starts from 1.

Parameters

coeffs : list of float List of coefficients. gate_time : float Total time of Pulse. Used to scale the basis functions. ramp_ratio : float, optional Ratio of the ramp time to the total time. Default is 0.2. backend : str, optional “cpu” or “gpu”. Default is “cpu”. **kwargs : dict Additional keyword arguments to pass to ControlPulse.

Initialization

Initializes a FourierPulse object.

Parameters

coeffs : list of float List of coefficients. gate_time : float Total time of Pulse. Used to scale the basis functions. ramp_ratio : float, optional Ratio of the ramp time to the total time. Default is 0.2. backend : str, optional “cpu” or “gpu”. Default is “cpu”. **kwargs : dict Additional keyword arguments to pass to ControlPulse.

envelope(tlist)

Generates a pulse array given a timelist.

Parameters

tlist : array_like List of time points.

Returns

array_like Pulse array.