qse.calc

qse.calc#

Interface to different QSE calculators.

Submodules#

Classes#

`Calculator`	Base-class for all QSE calculators.
`ExactSimulator`	A calculator that evoles the qubit system exactly.
`Myqlm`	QSE-Calculator for MyQLM.
`Pulser`	QSE-Calculator for pulser.

Functions#

blockade_radius(rabi_frequency[, c6])

Calculate the blockade radius based on the Rabi frequency and C6 coefficient.

Package Contents#

qse.calc.blockade_radius(rabi_frequency, c6=5420158.53)[source]#

Calculate the blockade radius based on the Rabi frequency and C6 coefficient. The blockade radius is a measure of the distance at which the Rydberg blockade effect occurs, preventing simultaneous excitation of nearby atoms.

Parameters:

rabi_frequency (float) – The Rabi frequency (in rads/μs) associated with the atomic transition.
c6 (float, optional) – The C6 coefficient (in rads/μs * μm^6) for the van der Waals interaction. Default is 5420158.53.

Returns:

float – The blockade radius (in μm).

Notes

The blockade radius is calculated as:

\[r_b = \left( \frac{C_6}{\Omega} \right)^{1/6}\]

where \(\Omega\) is the Rabi frequency and \(C_6\) is the van der Waals coefficient.

class qse.calc.Calculator(qbits, label: str, is_calculator_available: bool, installation_message: str)[source]#

Base-class for all QSE calculators.

Parameters:

label (str) – Name used for all files. Not supported by all calculators. May contain a directory, but please use the directory parameter for that instead.
qbits (Qbits object) – Optional Qbits object to which the calculator will be attached. When restarting, qbits will get its positions and unit-cell updated from file.

abstract calculate()[source]#: Do the calculation.

get_spins()[source]#

Get spin expectation values. If the hamiltonian isn’t simulated, it triggers simulation first.

Returns:: np.ndarray – Array of Nx3 containing spin expectation values.

class qse.calc.ExactSimulator(amplitude=None, detuning=None)[source]#

A calculator that evoles the qubit system exactly. Only supported for a single qubit.

Parameters:

amplitude (qse.Signal, qse.Signals) – The amplitude pulse.
detuning (qse.Signal, qse.Signals) – The detuning pulse.

Notes

For a single qubit the Hamiltonian is

\[H = \frac{\Omega}{2} e^{-i\phi}|0\rangle\langle 1| + \frac{\Omega}{2} e^{i\phi}|0\rangle\langle 1| -\delta|1\rangle\langle 1|\]

where \(\Omega\) is the amplitude, \(\phi\) the phase and \(\delta\) the detuning. Setting the phase to zero and adding a constant \(I\delta/2\) we get

\[H = \frac{\Omega X + \delta Z}{2}\]

Then the time evolution unitary is given by

\[U(t) = e^{-iH t} = \cos(\Delta t/2) I - i \sin(\Delta t/2) \frac{\Omega X + \delta Z}{\Delta}\]

Where \(\Delta=\sqrt{\delta^2+\Omega^2}\).

class qse.calc.Myqlm(qbits=None, amplitude=None, detuning=None, qpu=None, label='myqlm-run', wtimes=True)[source]#

Bases: qse.calc.calculator.Calculator

QSE-Calculator for MyQLM.

Parameters:

qbits (qse.Qbits) – The qbits object.
amplitude (qse.Signal) – The amplitude pulse.
detuning (qse.Signal) – The detuning pulse.
qpu (qat.qpus) – The Quantum Processing Unit for executing the job.
label (str) – The label. Defaults to “pulser-run”.
wtimes (bool) – Whether to print the times. Defaults to True.

calculate()[source]#: Run the calculation.

class qse.calc.Pulser(qbits=None, amplitude=None, detuning=None, channel='rydberg_global', magnetic_field=None, device=None, emulator=None, label='pulser-run', wtimes=True)[source]#

Bases: qse.calc.calculator.Calculator

QSE-Calculator for pulser.

Parameters:

qbits (qse.Qbits) – The qbits object.
amplitude (qse.Signal, qse.Signals, pulser.waveforms.Waveform) – The amplitude pulse.
detuning (qse.Signal, qse.Signals, pulser.waveforms.Waveform) – The detuning pulse.
channel (str) – Which channel to use. For example “rydberg_global” for Rydberg or “mw_global” for microwave. Defaults to “rydberg_global”.
magnetic_field (np.ndarray | list) – A magnetic field. Must be a 3-component array or list. Can only be passed when using the Microwave channel (“mw_global”).
device (pulser.devices.Device) – The device. Defaults to pulser.devices.MockDevice.
emulator – The emulator. Defaults to QutipEmulator.
label (str) – The label. Defaults to “pulser-run”.
wtimes (bool) – Whether to print the times. Defaults to True.

Examples

A simple example of using the Pulser calculator:

>>> qbits = qse.lattices.chain(4.0, 4)
>>> duration = 400
>>> pulser_calc = qse.calc.Pulser(
...     qbits=qbits,
...     amplitude=qse.Signal([1.01], duration),
...     detuning=qse.Signal([0.12], duration),
... )
>>> pulser_calc.build_sequence()
>>> pulser_calc.calculate()
>>> pulser_calc.get_spins()

Notes

Pulser will only use the x-y coordinates of the Qbits object.

Pulser is an open-source Python software package. It provides easy-to-use libraries for designing and simulating pulse sequences that act on programmable arrays of neutral qbits, a promising platform for quantum computation and simulation. Online documentation: https://pulser.readthedocs.io White paper: Quantum 6, 629 (2022) Source code: pasqal-io/Pulser License: Apache 2.0 - see [LICENSE](pasqal-io/Pulser) for details.

build_sequence()[source]#: Build the sequence of operations involving the qubit coordinates, amplitude pulse and detuning pulse.

calculate(progress=True)[source]#: Run the calculation.