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sf.apps.qchem.vibronic.sample

sample(t, U1, r, U2, alpha, n_samples, loss=0.0)[source]

Generate samples for computing vibronic spectra. The following gates are applied to input vacuum states:

  1. Two-mode squeezing on all \(2N\) modes with parameters t

  2. Interferometer U1 on the first \(N\) modes

  3. Squeezing on the first \(N\) modes with parameters r

  4. Interferometer U2 on the first \(N\) modes

  5. Displacement on the first \(N\) modes with parameters alpha

A sample is generated by measuring the number of photons in each of the \(2N\) modes. In the special case that all of the two-mode squeezing parameters t are zero, only \(N\) modes are considered, which speeds up calculations.

Example usage:

>>> formic = data.Formic()
>>> w = formic.w
>>> wp = formic.wp
>>> Ud = formic.Ud
>>> delta = formic.delta
>>> T = 0
>>> t, U1, r, U2, alpha = gbs_params(w, wp, Ud, delta, T)
>>> sample(t, U1, r, U2, alpha, 2, 0.0)
[[0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
Parameters

  • t (array) – two-mode squeezing parameters

  • U1 (array) – unitary matrix for the first interferometer

  • r (array) – squeezing parameters

  • U2 (array) – unitary matrix for the second interferometer

  • alpha (array) – displacement parameters

  • n_samples (int) – number of samples to be generated

  • loss (float) – loss parameter denoting the fraction of generated photons that are lost

Returns

a list of samples from GBS

Return type

list[list[int]]

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